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Xiao Y, Yang D, Zhang SB, Mo YX, Dong YY, Wang KF, He LY, Dong B, Dossa GGO, Zhang JL. Nitrogen-fixing and non-nitrogen-fixing legume plants differ in leaf nutrient concentrations and relationships between photosynthetic and hydraulic traits. Tree Physiol 2024:tpae048. [PMID: 38691446 DOI: 10.1093/treephys/tpae048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 03/12/2024] [Accepted: 04/30/2024] [Indexed: 05/03/2024]
Abstract
Legumes account for a significant proportion of plants in the terrestrial ecosystems. Nitrogen-fixing capability of certain legumes is a pivotal trait that contributes to their ecological dominance. Yet, the functional traits and trait relationships between N-fixer and non-N-fixer legumes are poorly understood. Here, we investigated 27 functional traits associated with morphology, nutrients, hydraulic conductance, and photosynthesis in 42 woody legumes (19 N-fixers and 23 non-N-fixers) in a common garden. Our results showed that N-fixers had higher specific leaf area, photosynthetic phosphorus (P) use efficiency, leaf nitrogen (N) and iron concentrations on both area and mass basis, N/P ratio, and carbon (C) to P ratio, but lower wood density, area-based maximum photosynthetic rate (Aa), photosynthetic N use efficiency, leaf mass- and area-based P and molybdenum and area-based boron concentrations, and C/N ratio, compared to non-N-fixers. The mass-based maximum photosynthetic rate (Am), stomatal conductance (gs), intrinsic water use efficiency (WUEi), mass- and area-based leaf potassium and mass-based boron concentrations, leaf hydraulic conductance (Kleaf), and whole-shoot hydraulic conductance (Kshoot) showed no difference between N-fixers and non-N-fixers. Significant positive associations between all hydraulic and photosynthetic trait pairs were found in N-fixers, but only one pair (Kshoot-Aa) in non-N-fixers, suggesting that hydraulic conductance plays a more important role in mediating photosynthetic capacity in N-fixers compared to non-N-fixers. Higher mass-based leaf N was linked to lower time-integrated gs and higher WUEi among non-N-fixer legumes or all legumes pooled after phylogeny was considered. Moreover, mass-based P concentration was positively related to Am and gs in N-fixers, but not in non-N-fixers, indicating that the photosynthetic capacity and stomatal conductance in N-fixers were more dependent on leaf P status than in non-N-fixers. These findings expand our understanding of the trait-based ecology within and across N-fixer and non-N-fixer legumes in tropics.
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Affiliation(s)
- Yan Xiao
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
- Millennium Seed Bank, Royal Botanic Gardens Kew, Wakehurst, West Sussex, RH17 6TN, UK
| | - Da Yang
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China
| | - Shu-Bin Zhang
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China
| | - Yu-Xuan Mo
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China
| | - Yi-Yi Dong
- School of Forest Resources and Conservation, University of Florida, Gainesville, FL 32603, USA
| | - Ke-Fei Wang
- School of Biological and Chemical Sciences, Puer University, Puer, Yunnan 665000, China
| | - Ling-Yun He
- College of Forestry, Jiangxi Agricultural University, Nanchang 330045, China
| | - Bing Dong
- School of Biology, University of St Andrews, Dyers Brae, St Andrews KY16 9TH, UK
| | - Gbadamassi G O Dossa
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China
| | - Jiao-Lin Zhang
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China
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West AG, Bloy ST, Skelton RP, Midgley JJ. Hydraulic segmentation explains differences in loss of branch conductance caused by fire. Tree Physiol 2023; 43:2121-2130. [PMID: 37672220 PMCID: PMC10714316 DOI: 10.1093/treephys/tpad108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 08/28/2023] [Accepted: 09/03/2023] [Indexed: 09/07/2023]
Abstract
The hydraulic death hypothesis suggests that fires kill trees by damaging the plant's hydraulic continuum in addition to stem cambium. A corollary to this hypothesis is that plants that survive fires possess 'pyrohydraulic' traits that prevent heat-induced embolism formation in the xylem and aid post-fire survival. We examine whether hydraulic segmentation within stem xylem may act as such a trait. To do so, we measured the percentage loss of conductance (PLC) and vulnerability to embolism axially along segments of branches exposed to heat plumes in two differing species, fire-tolerant Eucalyptus cladocalyx F. Muell and fire-sensitive Kiggelaria africana L., testing model predictions that fire-tolerant species would exhibit higher degrees of hydraulic segmentation (greater PLC in the distal parts of the branch than the basal) than fire-intolerant species (similar PLC between segments). Following exposure to a heat plume, K. africana suffered between 73 and 84% loss of conductance in all branch segments, whereas E. cladocalyx had 73% loss of conductance in whole branches, including the distal tips, falling to 29% in the most basal part of the branch. There was no evidence for differences in resistance segmentation between the species, and there was limited evidence for differences in distal vulnerability to embolism across the branches. Hydraulic segmentation in E. cladocalyx may enable it to resprout effectively post-fire with a functional hydraulic system. The lack of hydraulic segmentation in K. africana reveals the need to understand possible trade-offs associated with hydraulic segmentation in long-lived woody species with respect to drought and fire.
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Affiliation(s)
- Adam G West
- Department of Biological Sciences, University Avenue, University of Cape Town, 7701, Cape Town, South Africa
| | - Shonese T Bloy
- Department of Biological Sciences, University Avenue, University of Cape Town, 7701, Cape Town, South Africa
| | - Robert P Skelton
- SAEON Fynbos Node, Centre for Biodiversity Conservation, Kirstenbosch Gardens, 7708, Cape Town, South Africa
- Animal, Plant and Environmental Sciences, University of the Witwatersrand, 1 Jan Smuts Ave, Braamfontein, 2001, Johannesburg, South Africa
| | - Jeremy J Midgley
- Department of Biological Sciences, University Avenue, University of Cape Town, 7701, Cape Town, South Africa
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Chomthong M, Griffiths H. Prospects and perspectives: inferring physiological and regulatory targets for CAM from molecular and modelling approaches. Ann Bot 2023; 132:583-596. [PMID: 37742290 PMCID: PMC10799989 DOI: 10.1093/aob/mcad142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Revised: 08/26/2023] [Accepted: 09/21/2023] [Indexed: 09/26/2023]
Abstract
BACKGROUND AND SCOPE This review summarizes recent advances in our understanding of Crassulacean Acid Metabolism (CAM) by integrating evolutionary, ecological, physiological, metabolic and molecular perspectives. A number of key control loops which moderate the expression of CAM phases, and their metabolic and molecular control, are explored. These include nocturnal stomatal opening, activation of phosphoenolpyruvate carboxylase by a specific protein kinase, interactions with circadian clock control, as well as daytime decarboxylation and activation of Rubisco. The vacuolar storage and release of malic acid and the interplay between the supply and demand for carbohydrate reserves are also key metabolic control points. FUTURE OPPORTUNITIES We identify open questions and opportunities, with experimentation informed by top-down molecular modelling approaches allied with bottom-up mechanistic modelling systems. For example, mining transcriptomic datasets using high-speed systems approaches will help to identify targets for future genetic manipulation experiments to define the regulation of CAM (whether circadian or metabolic control). We emphasize that inferences arising from computational approaches or advanced nuclear sequencing techniques can identify potential genes and transcription factors as regulatory targets. However, these outputs then require systematic evaluation, using genetic manipulation in key model organisms over a developmental progression, combining gene silencing and metabolic flux analysis and modelling to define functionality across the CAM day-night cycle. From an evolutionary perspective, the origins and function of CAM succulents and responses to water deficits are set against the mesophyll and hydraulic limitations imposed by cell and tissue succulence in contrasting morphological lineages. We highlight the interplay between traits across shoots (3D vein density, mesophyll conductance and cell shrinkage) and roots (xylem embolism and segmentation). Thus, molecular, biophysical and biochemical processes help to curtail water losses and exploit rapid rehydration during restorative rain events. In the face of a changing climate, we hope such approaches will stimulate opportunities for future research.
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Affiliation(s)
- Methawi Chomthong
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, UK
| | - Howard Griffiths
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, UK
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Petit G, Mencuccini M, Carrer M, Prendin AL, Hölttä T. Axial conduit widening, tree height, and height growth rate set the hydraulic transition of sapwood into heartwood. J Exp Bot 2023; 74:5072-5087. [PMID: 37352139 DOI: 10.1093/jxb/erad227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 06/12/2023] [Indexed: 06/25/2023]
Abstract
The size-related xylem adjustments required to maintain a constant leaf-specific sapwood conductance (KLEAF) with increasing height (H) are still under discussion. Alternative hypotheses are that: (i) the conduit hydraulic diameter (Dh) at any position in the stem and/or (ii) the number of sapwood rings at stem base (NSWr) increase with H. In addition, (iii) reduced stem elongation (ΔH) increases the tip-to-base conductance through inner xylem rings, thus possibly the NSWr contributing to KLEAF. A detailed stem analysis showed that Dh increased with the distance from the ring apex (DCA) in all rings of a Picea abies and a Fagus sylvatica tree. Net of DCA effect, Dh did not increase with H. Using sapwood traits from a global dataset, NSWr increased with H, decreased with ΔH, and the mean sapwood ring width (SWrw) increased with ΔH. A numerical model based on anatomical patterns predicted the effects of H and ΔH on the conductance of inner xylem rings. Our results suggest that the sapwood/heartwood transition depends on both H and ΔH, and is set when the carbon allocation to maintenance respiration of living cells in inner sapwood rings produces a lower gain in total conductance than investing the same carbon in new vascular conduits.
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Affiliation(s)
- Giai Petit
- Università degli Studi di Padova, Dept. TeSAF, Viale dell'Università 16, 35020 Legnaro (PD), Italy
| | - Maurizio Mencuccini
- CREAF, Bellaterra (Cerdanyola del Vallès), E08193, Spain
- ICREA, Pg. Lluís Companys 23, Barcelona, 08010, Spain
| | - Marco Carrer
- Università degli Studi di Padova, Dept. TeSAF, Viale dell'Università 16, 35020 Legnaro (PD), Italy
| | - Angela Luisa Prendin
- Università degli Studi di Padova, Dept. TeSAF, Viale dell'Università 16, 35020 Legnaro (PD), Italy
- Department of Biology, Ecoinformatics and Biodiversity, Aarhus University, Ny Munkegade 114-116, building 1540, 8000 Aarhus C, Denmark University of Aarhus, Denmark
| | - Teemu Hölttä
- Institute for Atmospheric and Earth System Research/ Forest Sciences, Faculty of Agriculture and Forestry, University of Helsinki, Latokartanonkaari 7, FI 00014 Helsinki, Finland
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Ortega JKE. Theoretical Analyses of Turgor Pressure during Stress Relaxation and Water Uptake, and after Changes in Expansive Growth Rate When Water Uptake Is Normal and Reduced. Plants (Basel) 2023; 12:plants12091891. [PMID: 37176947 PMCID: PMC10181280 DOI: 10.3390/plants12091891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 04/28/2023] [Accepted: 05/03/2023] [Indexed: 05/15/2023]
Abstract
Turgor pressure provides the force needed to stress and deform the cell walls of plants, algae, and fungi during expansive growth. However, turgor pressure plays another subtle but equally important role in expansive growth of walled cells: it connects the two biophysical processes of water uptake and wall deformation to ensure that the volumetric rates of water uptake and enlargement of the cell wall chamber are equal. In this study, the role of turgor pressure as a 'connector' is investigated analytically by employing validated and established biophysical equations. The objective is to determine the effect of 'wall loosening' on the magnitude of turgor pressure. It is known that an increase or decrease in turgor pressure and/or wall loosening rate increases or decreases the expansive growth rate, respectively. Interestingly, it is shown that an increase in the wall loosening rate decreases the turgor pressure slightly, thus reducing the effect of wall loosening on increasing the expansive growth rate. Other analyses reveal that reducing the rate of water uptake results in a larger decrease in turgor pressure with the same increase in wall loosening rate, which further reduces the effect of wall loosening on increasing the expansive growth rate.
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Affiliation(s)
- Joseph K E Ortega
- Department of Mechanical Engineering, University of Colorado Denver, Denver, CO 80217-3364, USA
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Mandour H, Khazaei H, Stoddard FL, Dodd IC. Identifying physiological and genetic determinants of faba bean transpiration response to evaporative demand. Ann Bot 2023; 131:533-544. [PMID: 36655613 PMCID: PMC10072112 DOI: 10.1093/aob/mcad006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Accepted: 01/09/2023] [Indexed: 06/17/2023]
Abstract
BACKGROUND AND AIMS Limiting maximum transpiration rate (TR) under high vapour pressure deficit (VPD) works as a water conservation strategy. While some breeding programmes have incorporated this trait into some crops to boost yields in water-limited environments, its underlying physiological mechanisms and genetic regulation remain unknown for faba bean (Vicia faba). Thus, we aimed to identify genetic variation in the TR response to VPD in a population of faba bean recombinant inbred lines (RILs) derived from two parental lines with contrasting water use (Mélodie/2 and ILB 938/2). METHODS Plants were grown in well-watered soil in a climate-controlled glasshouse with diurnally fluctuating VPD and light conditions. Whole plant transpiration was measured in a gas exchange chamber that tightly regulated VPD around the shoot under constant light, while whole-plant hydraulic conductance and its components (root and stem hydraulic conductance) were calculated from dividing TR by water potential gradients measured with a pressure chamber. KEY RESULTS Although TR of Mélodie/2 increased linearly with VPD, ILB 938/2 limited its TR above 2.0 kPa. Nevertheless, Mélodie/2 had a higher leaf water potential than ILB 938/2 at both low (1.0 kPa) and high (3.2 kPa) VPD. Almost 90 % of the RILs limited their TR at high VPD with a break-point (BP) range of 1.5-3.0 kPa and about 10 % had a linear TR response to VPD. Thirteen genomic regions contributing to minimum and maximum transpiration, and whole-plant and root hydraulic conductance, were identified on chromosomes 1 and 3, while one locus associated with BP transpiration was identified on chromosome 5. CONCLUSIONS This study provides insight into the physiological and genetic control of transpiration in faba bean and opportunities for marker-assisted selection to improve its performance in water-limited environments.
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Affiliation(s)
- Hend Mandour
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK
- Genetic Engineering and Biotechnology Research Institute, National Research Centre, Giza, Egypt
| | - Hamid Khazaei
- Natural Resources Institute Finland (LUKE), Latokartanonkaari 9, 00790 Helsinki, Finland
| | - Frederick L Stoddard
- Department of Agricultural Sciences, Viikki Plant Science Centre and Helsinki Institute of Sustainability Science, PO Box 27 (Latokartanonkaari 5-7), FI-00014 University of Helsinki, Helsinki, Finland
| | - Ian C Dodd
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK
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Zhang Q, Tang W, Xiong Z, Peng S, Li Y. Stomatal conductance in rice leaves and panicles responds differently to abscisic acid and soil drought. J Exp Bot 2023; 74:1551-1563. [PMID: 36516416 DOI: 10.1093/jxb/erac496] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Accepted: 12/12/2022] [Indexed: 06/17/2023]
Abstract
Improvement of photosynthesis in non-foliar green tissues is beneficial for enhancing crop yield. Recently, we have demonstrated that panicle stomatal conductance is a major limiting factor for photosynthesis. However, mechanisms underlying the responses of panicle stomatal conductance (gs,panicle) and photosynthesis (Apanicle) to environmental stimuli remain unknown. In the present study, the responses of gs,panicle and leaf stomatal conductance (gs,leaf) to exogenous application of abscisic acid and step-changes in vapor pressure deficit were investigated at the anthesis stage in pot-grown rice plants. Furthermore, the effects of drought on Apanicle and leaf photosynthesis (Aleaf) were examined. Smearing and xylem feeding of abscisic acid significantly decreased gs,leaf. In contrast, while smearing of abscisic acid substantially increased gs,panicle, its xylem feeding dramatically decreased gs,panicle. In addition, both gs,leaf and gs,panicle effectively responded to step changes in vapor pressure deficit. Furthermore, both Aleaf and Apanicle were sensitive to plant dehydration; however, given the lower sensitivity of panicle water potential than leaf water potential to drought, Apanicle was less sensitive to soil drought than Aleaf. These findings indicate that gs,panicle is hydropassively regulated, while panicle photosynthesis is less sensitive to drought.
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Affiliation(s)
- Qiangqiang Zhang
- National Key Laboratory of Crop Genetic Improvement, Ministry of Agriculture Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Wei Tang
- National Key Laboratory of Crop Genetic Improvement, Ministry of Agriculture Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Zhuang Xiong
- National Key Laboratory of Crop Genetic Improvement, Ministry of Agriculture Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Shaobing Peng
- National Key Laboratory of Crop Genetic Improvement, Ministry of Agriculture Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Yong Li
- National Key Laboratory of Crop Genetic Improvement, Ministry of Agriculture Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
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Jerbi A, Laur J, Lajoie K, Gallant PP, Barnabé S, Pitre FE, Labrecque M. Irrigation with primary wastewater alters wood anatomy and composition in willow Salix miyabeana SX67. Front Plant Sci 2023; 14:1087035. [PMID: 36938004 PMCID: PMC10018808 DOI: 10.3389/fpls.2023.1087035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 02/14/2023] [Indexed: 06/18/2023]
Abstract
Traditional treatment of wastewaters is a burden for local governments. Using short rotation coppice willow (SRCW) as vegetal filter has several environmental and economic benefits. Here, we investigated the effect of primary wastewater irrigation on wood structure and composition of the willow cultivar Salix miyabeana 'SX67' following two years of growth. Compared to unirrigated plants (UI), stem sections of plants irrigated with primary wastewater (WWD) showed an unexpected decrease of hydraulic conductance (KS) associated with a decrease in vessel density but not vessel diameter. The majority (86%) of vessels had diameters range groups [20-30[, [30-40[and [40-50[µm and contributed to > 75% of theoretical KS, while the group class [50-60[µm (less than 10% of vessels) still accounted for > 20% of total KS regardless irrigation treatments. WWD significantly alters the chemical composition of wood with an increase of glucan content by 9 to 16.4% and a decrease of extractives by 35.3 to 36.4% when compared to UI or to plants irrigated with potable water (PW). The fertigation did also increase the proportion of the tension wood which highly correlated with glucan content. In the context of energetic transition and mitigation of climate change, such results are of high interest since WWD effectively permit the phytofiltration of large amounts of organic contaminated effluents without impairing SRCW physiology.
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Affiliation(s)
- Ahmed Jerbi
- Institut de recherche en biologie végétale, Université de Montréal, Montréal, QC, Canada
| | - Joan Laur
- Institut de recherche en biologie végétale, Université de Montréal, Montréal, QC, Canada
- Montreal Botanical Garden, Research and Development Division, Montréal, QC, Canada
| | - Kevin Lajoie
- Institut d’Innovations sur les Écomatériaux, Écoproduits et Écoénergies à base de biomasse (I2E3), Université du Québec à Trois-Rivières, Trois-Rivières, Canada
| | | | - Simon Barnabé
- Institut d’Innovations sur les Écomatériaux, Écoproduits et Écoénergies à base de biomasse (I2E3), Université du Québec à Trois-Rivières, Trois-Rivières, Canada
| | - Frederic E. Pitre
- Institut de recherche en biologie végétale, Université de Montréal, Montréal, QC, Canada
- Montreal Botanical Garden, Research and Development Division, Montréal, QC, Canada
| | - Michel Labrecque
- Institut de recherche en biologie végétale, Université de Montréal, Montréal, QC, Canada
- Montreal Botanical Garden, Research and Development Division, Montréal, QC, Canada
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Pittermann J, Baer A, Campany C, Jansen S, Holmlund H, Schuettpelz E, Mehltreter K, Watkins JE. A reduced role for water transport during the Cenozoic evolution of epiphytic Eupolypod ferns. New Phytol 2023; 237:1745-1758. [PMID: 36484140 DOI: 10.1111/nph.18667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 11/15/2022] [Indexed: 06/17/2023]
Abstract
The Cretaceous-Cenozoic expansion of tropical forests created canopy space that was subsequently occupied by diverse epiphytic communities including Eupolypod ferns. Eupolypods proliferated in this more stressful niche, where lower competition enabled the adaptive radiation of thousands of species. Here, we examine whether xylem traits helped shape the Cenozoic radiation of Eupolypod ferns. We characterized the petiole xylem anatomy of 39 species belonging to the Eupolypod I and Eupolypod II clades occupying the epiphytic, hemiepiphytic, and terrestrial niche, and we assessed vulnerability to embolism in a subset of species. The transition to the canopy was associated with reduced xylem content and smaller tracheid diameters, but no differences were found in species vulnerability to embolism and pit membrane thickness. Phylogenetic analyses support selection for traits associated with reduced water transport in Eupolypod 1 species. We posit that in Eupolypod epiphytes, selection favored water retention via thicker leaves and lower stomatal density over higher rates of water transport. Consequently, lower leaf water loss was coupled with smaller quantities of xylem and narrower tracheid diameters. Traits associated with water conservation were evident in terrestrial Eupolypod 1 ferns and may have predisposed this clade toward radiation in the canopy.
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Affiliation(s)
- Jarmila Pittermann
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, 95060, USA
| | - Alex Baer
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, 95060, USA
| | - Courtney Campany
- Department of Biology, Shepherd University, Shepherdstown, WV, 25443, USA
| | - Steven Jansen
- Institute for Systematic Botany and Ecology, University of Ulm, Ulm, 89081, Germany
| | - Helen Holmlund
- Natural Science Division, Pepperdine University, Malibu, CA, 90263, USA
| | - Eric Schuettpelz
- Department of Botany, National Museum of Natural History, Smithsonian Institution, Washington, DC, 20560, USA
| | - Klaus Mehltreter
- Red de Ecologia Funcíonal, Instituto de Ecología A.C, Xalapa, Veracruz, 91073, Mexico
| | - James E Watkins
- Department of Biology, Colgate University, Hamilton, NY, 13346, USA
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Martynenko E, Arkhipova T, Akhiyarova G, Sharipova G, Galin I, Seldimirova O, Ivanov R, Nuzhnaya T, Finkina E, Ovchinnikova T, Kudoyarova G. Effects of a Pseudomonas Strain on the Lipid Transfer Proteins, Appoplast Barriers and Activity of Aquaporins Associated with Hydraulic Conductance of Pea Plants. Membranes (Basel) 2023; 13:208. [PMID: 36837711 PMCID: PMC9959925 DOI: 10.3390/membranes13020208] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 01/23/2023] [Accepted: 02/02/2023] [Indexed: 06/16/2023]
Abstract
Lipid transfer proteins (LTPs) are known to be involved in suberin deposition in the Casparian bands of pea roots, thereby reinforcing apoplast barriers. Moreover, the Pseudomonas mandelii IB-Ki14 strain accelerated formation of the Casparian bands in wheat plants, although involvement of LTPs in the process was not studied. Here, we investigated the effects of P. mandelii IB-Ki14 on LTPs, formation of the Casparian bands, hydraulic conductance and activity of aquaporins (AQPs) in pea plants. RT PCR showed a 1.6-1.9-fold up-regulation of the PsLTP-coding genes and an increase in the abundance of LTP proteins in the phloem of pea roots induced by the treatment with P. mandelii IB-Ki14. The treatment was accompanied with increased deposition of suberin in the Casparian bands. Hydraulic conductance did not decrease in association with the bacterial treatment despite strengthening of the apoplast barriers. At the same time, the Fenton reagent, serving as an AQPs inhibitor, decreased hydraulic conductance to a greater extent in treated plants relative to the control group, indicating an increase in the AQP activity by the bacteria. We hypothesize that P. mandelii IB-Ki14 stimulates deposition of suberin, in the biosynthesis of which LTPs are involved, and increases aquaporin activity, which in turn prevents a decrease in hydraulic conductance due to formation of the apoplast barriers in pea roots.
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Affiliation(s)
- Elena Martynenko
- Ufa Institute of Biology, Ufa Federal Research Centre, RAS, Prospekt Oktyabrya, 69, 450054 Ufa, Russia
| | - Tatiana Arkhipova
- Ufa Institute of Biology, Ufa Federal Research Centre, RAS, Prospekt Oktyabrya, 69, 450054 Ufa, Russia
| | - Guzel Akhiyarova
- Ufa Institute of Biology, Ufa Federal Research Centre, RAS, Prospekt Oktyabrya, 69, 450054 Ufa, Russia
| | - Guzel Sharipova
- Ufa Institute of Biology, Ufa Federal Research Centre, RAS, Prospekt Oktyabrya, 69, 450054 Ufa, Russia
| | - Ilshat Galin
- Ufa Institute of Biology, Ufa Federal Research Centre, RAS, Prospekt Oktyabrya, 69, 450054 Ufa, Russia
| | - Oksana Seldimirova
- Ufa Institute of Biology, Ufa Federal Research Centre, RAS, Prospekt Oktyabrya, 69, 450054 Ufa, Russia
| | - Ruslan Ivanov
- Ufa Institute of Biology, Ufa Federal Research Centre, RAS, Prospekt Oktyabrya, 69, 450054 Ufa, Russia
| | - Tatiana Nuzhnaya
- Ufa Institute of Biology, Ufa Federal Research Centre, RAS, Prospekt Oktyabrya, 69, 450054 Ufa, Russia
| | - Ekaterina Finkina
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya Str., 16/10, 117997 Moscow, Russia
| | - Tatiana Ovchinnikova
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya Str., 16/10, 117997 Moscow, Russia
| | - Guzel Kudoyarova
- Ufa Institute of Biology, Ufa Federal Research Centre, RAS, Prospekt Oktyabrya, 69, 450054 Ufa, Russia
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11
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Sharipova G, Ivanov R, Veselov D, Akhiyarova G, Seldimirova O, Galin I, Fricke W, Vysotskaya L, Kudoyarova G. Effect of Salinity on Stomatal Conductance, Leaf Hydraulic Conductance, HvPIP2 Aquaporin, and Abscisic Acid Abundance in Barley Leaf Cells. Int J Mol Sci 2022; 23:ijms232214282. [PMID: 36430758 PMCID: PMC9694007 DOI: 10.3390/ijms232214282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 11/14/2022] [Accepted: 11/15/2022] [Indexed: 11/19/2022] Open
Abstract
The stomatal closure of salt-stressed plants reduces transpiration bringing about the maintenance of plant tissue hydration. The aim of this work was to test for any involvement of aquaporins (AQPs) in stomatal closure under salinity. The changes in the level of aquaporins in the cells were detected with the help of an immunohistochemical technique using antibodies against HvPIP2;2. In parallel, leaf sections were stained for abscisic acid (ABA). The effects of salinity were compared to those of exogenously applied ABA on leaf HvPIP2;2 levels and the stomatal and leaf hydraulic conductance of barley plants. Salinity reduced the abundance of HvPIP2;2 in the cells of the mestome sheath due to it being the more likely hydraulic barrier due to the deposition of lignin, accompanied by a decline in the hydraulic conductivity, transpiration, and ABA accumulation. The effects of exogenous ABA differed from those of salinity. This hormone decreased transpiration but increased the shoot hydraulic conductivity and PIP2;2 abundance. The difference in the action of the exogenous hormone and salinity may be related to the difference in the ABA distribution between leaf cells, with the hormone accumulating mainly in the mesophyll of salt-stressed plants and in the cells of the bundle sheaths of ABA-treated plants. The obtained results suggest the following succession of events: salinity decreases water flow into the shoots due to the decreased abundance of PIP2;2 and hydraulic conductance, while the decline in leaf hydration leads to the production of ABA in the leaves and stomatal closure.
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Affiliation(s)
- Guzel Sharipova
- Ufa Institute of Biology of Ufa Federal Research Centre of the Russian Academy of Sciences, pr. Octyabrya 69, 450054 Ufa, Russia
| | - Ruslan Ivanov
- Ufa Institute of Biology of Ufa Federal Research Centre of the Russian Academy of Sciences, pr. Octyabrya 69, 450054 Ufa, Russia
| | - Dmitriy Veselov
- Ufa Institute of Biology of Ufa Federal Research Centre of the Russian Academy of Sciences, pr. Octyabrya 69, 450054 Ufa, Russia
| | - Guzel Akhiyarova
- Ufa Institute of Biology of Ufa Federal Research Centre of the Russian Academy of Sciences, pr. Octyabrya 69, 450054 Ufa, Russia
| | - Oksana Seldimirova
- Ufa Institute of Biology of Ufa Federal Research Centre of the Russian Academy of Sciences, pr. Octyabrya 69, 450054 Ufa, Russia
| | - Ilshat Galin
- Ufa Institute of Biology of Ufa Federal Research Centre of the Russian Academy of Sciences, pr. Octyabrya 69, 450054 Ufa, Russia
| | - Wieland Fricke
- School of Biology and Environmental Science, University College Dublin, Belfield, D04 V1W8 Dublin, Ireland
| | - Lidiya Vysotskaya
- Ufa Institute of Biology of Ufa Federal Research Centre of the Russian Academy of Sciences, pr. Octyabrya 69, 450054 Ufa, Russia
| | - Guzel Kudoyarova
- Ufa Institute of Biology of Ufa Federal Research Centre of the Russian Academy of Sciences, pr. Octyabrya 69, 450054 Ufa, Russia
- Correspondence: ; Tel.: +7-347-235-53-62
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12
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Clément C, Schneider HM, Dresbøll DB, Lynch JP, Thorup-Kristensen K. Root and xylem anatomy varies with root length, root order, soil depth and environment in intermediate wheatgrass (Kernza®) and alfalfa. Ann Bot 2022; 130:367-382. [PMID: 35468194 PMCID: PMC9486898 DOI: 10.1093/aob/mcac058] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 04/25/2022] [Indexed: 06/08/2023]
Abstract
BACKGROUND AND AIMS Deep roots (i.e. >1 m depth) are important for crops to access water when the topsoil is dry. Root anatomy and hydraulic conductance play important roles in the uptake of soil water, particularly water located deep in the soil. We investigated whether root and xylem anatomy vary as a function of root type, order and length, or with soil depth in roots of two deep-rooted perennial crops: intermediate wheatgrass [Thinopyrum intermedium (Kernza®)] and alfalfa (Medicago sativa). We linked the expression of these anatomical traits to the plants' capacity to take up water from deep soil layers. METHODS Using laser ablation tomography, we compared the roots of the two crops for cortical area, number and size of metaxylem vessels, and their estimated root axial hydraulic conductance (ERAHCe). The deepest roots investigated were located at soil depths of 2.25 and at 3.5 m in the field and in rhizoboxes, respectively. Anatomical differences were characterized along 1-m-long individual roots, among root types and orders, as well as between environmental conditions. KEY RESULTS For both crops, a decrease in the number and diameter, or both, of metaxylem vessels along individual root segments and with soil depth in the field resulted in a decrease in ERAHCe. Alfalfa, with a greater number of metaxylem vessels per root throughout the soil profile and, on average, a 4-fold greater ERAHCe, took up more water from the deep soil layers than intermediate wheatgrass. Root anatomical traits were significantly different across root types, classes and growth conditions. CONCLUSIONS Root anatomical traits are important tools for the selection of crops with enhanced exploitation of deep soil water. The development and breeding of perennial crops for improved subsoil exploitation will be aided by greater understanding of root phenotypes linked to deep root growth and activity.
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Affiliation(s)
| | - Hannah M Schneider
- Department of Plant Science, Pennsylvania State University, University Park, PA 16802, USA
| | - Dorte Bodin Dresbøll
- Department of Plant and Environmental Science, University of Copenhagen, 1871 Frederiksberg, Denmark
| | - Jonathan P Lynch
- Department of Plant Science, Pennsylvania State University, University Park, PA 16802, USA
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13
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Liu C, Wang Q, Mäkelä A, Hökkä H, Peltoniemi M, Hölttä T. A model bridging waterlogging, stomatal behavior and water use in trees in drained peatland. Tree Physiol 2022; 42:1736-1749. [PMID: 35383852 PMCID: PMC9460983 DOI: 10.1093/treephys/tpac037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 04/04/2022] [Indexed: 06/14/2023]
Abstract
Waterlogging causes hypoxic or anoxic conditions in soils, which lead to decreases in root and stomatal hydraulic conductance. Although these effects have been observed in a variety of plant species, they have not been quantified continuously over a range of water table depths (WTD) or soil water contents (SWC). To provide a quantitative theoretical framework for tackling this issue, we hypothesized similar mathematical descriptions of waterlogging and drought effects on whole-tree hydraulics and constructed a hierarchical model by connecting optimal stomata and soil-to-leaf hydraulic conductance models. In the model, the soil-to-root conductance is non-monotonic with WTD to reflect both the limitations by water under low SWC and by hypoxic effects associated with inhibited oxygen diffusion under high SWC. The model was parameterized using priors from literature and data collected over four growing seasons from Scots pine (Pinus sylvestris L.) trees grown in a drained peatland in Finland. Two reference models (RMs) were compared with the new model, RM1 with no belowground hydraulics and RM2 with no waterlogging effects. The new model was more accurate than the RMs in predicting transpiration rate (fitted slope of measured against modeled transpiration rate = 0.991 vs 0.979 (RM1) and 0.984 (RM2), R2 = 0.801 vs 0.665 (RM1) and 0.776 (RM2)). Particularly, RM2's overestimation of transpiration rate under shallow water table conditions (fitted slope = 0.908, R2 = 0.697) was considerably reduced by the new model (fitted slope = 0.956, R2 = 0.711). The limits and potential improvements of the model are discussed.
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Affiliation(s)
- Che Liu
- Department of Forest Sciences, Faculty of Agriculture and Forestry, University of Helsinki, Latokartanonkaari 7, P.O. Box 27, Helsinki 00014, Finland
- Institute for Atmospheric and Earth System Research (INAR), University of Helsinki, Latokartanonkaari 7, P.O. Box 27, Helsinki 00014, Finland
| | | | - Annikki Mäkelä
- Department of Forest Sciences, Faculty of Agriculture and Forestry, University of Helsinki, Latokartanonkaari 7, P.O. Box 27, Helsinki 00014, Finland
- Institute for Atmospheric and Earth System Research (INAR), University of Helsinki, Latokartanonkaari 7, P.O. Box 27, Helsinki 00014, Finland
| | - Hannu Hökkä
- Natural Resources Institute Finland (Luke), Chi-Ling Street 45, 410076 Changsha, Hunan, Finland
| | - Mikko Peltoniemi
- Natural Resources Institute Finland (Luke), Chi-Ling Street 45, 410076 Changsha, Hunan, Finland
| | - Teemu Hölttä
- Department of Forest Sciences, Faculty of Agriculture and Forestry, University of Helsinki, Latokartanonkaari 7, P.O. Box 27, Helsinki 00014, Finland
- Institute for Atmospheric and Earth System Research (INAR), University of Helsinki, Latokartanonkaari 7, P.O. Box 27, Helsinki 00014, Finland
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14
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Salvi AM, Gosetti SG, Smith DD, Adams MA, Givnish TJ, McCulloh KA. Hydroscapes, hydroscape plasticity and relationships to functional traits and mesophyll photosynthetic sensitivity to leaf water potential in Eucalyptus species. Plant Cell Environ 2022; 45:2573-2588. [PMID: 35706133 DOI: 10.1111/pce.14380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 06/06/2022] [Accepted: 06/13/2022] [Indexed: 06/15/2023]
Abstract
The isohydric-anisohydric continuum describes the relative stringency of stomatal control of leaf water potential (ψleaf ) during drought. Hydroscape area (HA)-the water potential landscape over which stomata regulate ψleaf -has emerged as a useful metric of the iso/anisohydric continuum because it is strongly linked to several hydraulic, photosynthetic and structural traits. Previous research on HA focused on broad ecological patterns involving several plant clades. Here we investigate the relationships between HA and climatic conditions and functional traits across ecologically diverse but closely related species while accounting for phylogeny. Across a macroclimatic moisture gradient, defined by the ratio of mean annual precipitation to mean annual pan evaporation (P/Ep ), HA decreased with increased P/Ep across 10 Eucalyptus species. Greater anisohydry reflects lower turgor loss points and greater hydraulic safety, mirroring global patterns. Larger HA coincides with mesophyll photosynthetic capacity that is more sensitive to ψleaf . Hydroscapes exhibit little plasticity in response to variation in water supply, and the extent of plasticity does not vary with P/Ep of native habitats. These findings strengthen the case that HA is a useful metric for characterizing drought tolerance and water-status regulation.
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Affiliation(s)
- Amanda M Salvi
- Department of Botany, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Sophia G Gosetti
- Department of Botany, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Duncan D Smith
- Department of Botany, University of Wisconsin-Madison, Madison, Wisconsin, USA
- School of Ecosystem and Forest Sciences, University of Melbourne, Creswick, Victoria, Australia
- Swinburne University of Technology, Hawthorn, Victoria, Australia
| | - Mark A Adams
- Swinburne University of Technology, Hawthorn, Victoria, Australia
| | - Thomas J Givnish
- Department of Botany, University of Wisconsin-Madison, Madison, Wisconsin, USA
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15
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Cory ST, Smith WK, Anderson TM. First-year Acacia seedlings are anisohydric "water-spenders" but differ in their rates of water use. Am J Bot 2022; 109:1251-1261. [PMID: 35791878 PMCID: PMC9544296 DOI: 10.1002/ajb2.16032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 06/06/2022] [Accepted: 06/08/2022] [Indexed: 06/15/2023]
Abstract
PREMISE First-year seedlings (FYS) of tree species may be a critical demographic bottleneck in semi-arid, seasonally dry ecosystems such as savannas. Given the highly variable water availability and potentially strong FYS-grass competition for water, FYS water-use strategies may play a crucial role in FYS establishment in savannas and, ultimately, in tree-grass competition and coexistence. METHODS We examined drought responses in FYS of two tree species that are dominant on opposite ends of an aridity gradient in Serengeti, Acacia (=Vachellia) tortilis and A. robusta. In a glasshouse experiment, gas exchange and whole-plant hydraulic conductance (Kplant ) were measured as soil water potential (Ψsoil ) declined. Trajectory of the Ψleaf /Ψsoil relationship during drought elucidated the degree of iso/anisohydry. RESULTS Both species were strongly anisohydric "water-spenders," allowing rapid wet-season C gain after pulses of moisture availability. Despite being equally vulnerable to declines in Kplant under severe drought, they differed in their rates of water use. Acacia tortilis, which occurs in the more arid regions, initially had greater Kmax , transpiration (E), and photosynthesis (Anet ) than A. robusta. CONCLUSIONS This work demonstrates an important mechanism of FYS establishment in savannas: Rather than investing in drought tolerance, savanna FYS maximize gas exchange during wet periods at the expense of desiccation during dry seasons. FYS establishment appears dependent on high C uptake during the pulses of water availability that characterize habitats dominated by these species. This study increases our understanding of species-scale plant ecophysiology and ecosystem-scale patterns of tree-grass coexistence.
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Affiliation(s)
- Scott T. Cory
- Department of BiologyWake Forest University1834 Wake Forest RoadWinston‐SalemNC27106USA
| | - William K. Smith
- Department of BiologyWake Forest University1834 Wake Forest RoadWinston‐SalemNC27106USA
| | - T. Michael Anderson
- Department of BiologyWake Forest University1834 Wake Forest RoadWinston‐SalemNC27106USA
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16
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Jacob V, Choat B, Churchill AC, Zhang H, Barton CVM, Krishnananthaselvan A, Post AK, Power SA, Medlyn BE, Tissue DT. High safety margins to drought-induced hydraulic failure found in five pasture grasses. Plant Cell Environ 2022; 45:1631-1646. [PMID: 35319101 DOI: 10.1111/pce.14318] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 02/13/2022] [Accepted: 03/16/2022] [Indexed: 06/14/2023]
Abstract
Determining the relationship between reductions in stomatal conductance (gs ) and leaf water transport during dehydration is key to understanding plant drought responses. While numerous studies have analysed the hydraulic function of woody species, minimal research has been conducted on grasses. Here, we sought to characterize hydraulic vulnerability in five widely-occurring pasture grasses (including both C3 and C4 grasses) and determine whether reductions in gs and leaf hydraulic conductance (Kleaf ) during dehydration could be attributed to xylem embolism. Using the optical vulnerability (OV) technique, we found that all species were highly resistant to xylem embolism when compared to other herbaceous angiosperms, with 50% xylem embolism (PX50 ) occurring at xylem pressures ranging from -4.4 to -6.1 MPa. We observed similar reductions in gs and Kleaf under mild water stress for all species, occurring well before PX50 . The onset of xylem embolism (PX12 ) occurred consistently after stomatal closure and 90% reduction of Kleaf . Our results suggest that factors other than xylem embolism are responsible for the majority of reductions in gs and Kleaf during drought and reductions in the productivity of pasture species under moderate drought may not be driven by embolism.
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Affiliation(s)
- Vinod Jacob
- Western Sydney University, Penrith, New South Wales, Australia
| | - Brendan Choat
- Western Sydney University, Penrith, New South Wales, Australia
| | | | - Haiyang Zhang
- Western Sydney University, Penrith, New South Wales, Australia
| | | | | | - Alison K Post
- Department of Biology, Colorado State University, Fort Collins, Colorado, USA
| | - Sally A Power
- Western Sydney University, Penrith, New South Wales, Australia
| | | | - David T Tissue
- Western Sydney University, Penrith, New South Wales, Australia
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17
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Zhang Q, Tang W, Peng S, Li Y. Limiting factors for panicle photosynthesis at the anthesis and grain filling stages in rice (Oryza sativa L.). Plant J 2022; 109:77-91. [PMID: 34704647 DOI: 10.1111/tpj.15554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 10/20/2021] [Accepted: 10/22/2021] [Indexed: 06/13/2023]
Abstract
Panicle photosynthesis is crucial for grain yield in cereal crops; however, the limiting factors for panicle photosynthesis are poorly understood, greatly impeding improvement in this trait. In the present study, pot experiments were conducted to investigate the limiting factors for panicle photosynthesis at the anthesis stage in seven rice genotypes and to examine the temporal variations in photosynthesis during the grain filling stage in the Liangyou 287 genotype. At the anthesis stage, leaf and panicle photosynthesis was positively correlated with stomatal conductance and maximum carboxylation rate, which were in turn associated with hydraulic conductance and nitrogen content, respectively. Panicle hydraulic conductance was positively correlated with the area of bundle sheaths in the panicle neck. During grain filling, leaf and panicle photosynthesis remained constant at the early stage but dramatically decreased from 8 to 9 days after anthesis. The trends of variations in panicle photosynthesis were consistent with those in stomatal conductance but not with those in maximum carboxylation rate. At first, the maximum carboxylation rate and respiration rate in the panicle increased, through elevated panicle nitrogen content, but then drastically decreased, as a result of dehydration. The present study systematically investigated the limiting factors for panicle photosynthesis, which are vital for improving photosynthesis and crop yield.
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Affiliation(s)
- Qiangqiang Zhang
- National Key Laboratory of Crop Genetic Improvement, College of Plant Science and Technology, Ministry of Agriculture Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Wei Tang
- National Key Laboratory of Crop Genetic Improvement, College of Plant Science and Technology, Ministry of Agriculture Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Shaobing Peng
- National Key Laboratory of Crop Genetic Improvement, College of Plant Science and Technology, Ministry of Agriculture Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Yong Li
- National Key Laboratory of Crop Genetic Improvement, College of Plant Science and Technology, Ministry of Agriculture Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
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18
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Beikircher B, Sack L, Ganthaler A, Losso A, Mayr S. Hydraulic-stomatal coordination in tree seedlings: tight correlation across environments and ontogeny in Acer pseudoplatanus. New Phytol 2021; 232:1297-1310. [PMID: 34176137 DOI: 10.1111/nph.17585] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 06/20/2021] [Indexed: 06/13/2023]
Abstract
Hydraulic conductance is recognized as a major determinant of gas exchange and productivity. However, whether this also applies to seedlings, a critically important stage for vegetation regeneration, has been largely unknown. We analyzed the hydraulic and stomatal conductance of leaves and shoots for 6-wk-old Acer pseudoplatanus seedlings emerging in different lowland and treeline habitats and under glasshouse conditions, respectively, as well as on 9-, 15- and 18-wk-old plants, and related findings to leaf and xylem anatomical traits. Treeline seedlings had higher leaf area-specific shoot hydraulic conductance (Kshoot-L ), and stomatal conductance (gs ), associated with wider xylem conduits, lower leaf area and higher stomatal density than lowland and glasshouse-grown plants. Across the first 18 wk of development, seedlings increased four-fold in absolute shoot hydraulic conductance (Kshoot ) and declined by half in Kshoot-L , with correlated shifts in xylem and leaf anatomy. Distal leaves had higher leaf hydraulic conductance (Kleaf ) and gs compared to basal leaves. Seedlings show strong variation across growth environments and ontogenetic shifts in hydraulic and anatomical parameters. Across growth sites, ontogenetic stages and leaf orders, gs was tightly correlated with Kshoot-L and Kleaf , balancing hydraulic supply with demand for the earliest stages of seedling establishment.
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Affiliation(s)
- Barbara Beikircher
- Department of Botany, University of Innsbruck, Sternwartestr. 15, Innsbruck, 6020, Austria
| | - Lawren Sack
- Department of Ecology and Evolutionary Biology, University of California (UCLA), 621 Charles E. Young Drive South, Los Angeles, CA, 90095, USA
| | - Andrea Ganthaler
- Department of Botany, University of Innsbruck, Sternwartestr. 15, Innsbruck, 6020, Austria
| | - Adriano Losso
- Department of Botany, University of Innsbruck, Sternwartestr. 15, Innsbruck, 6020, Austria
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, 2753, Australia
| | - Stefan Mayr
- Department of Botany, University of Innsbruck, Sternwartestr. 15, Innsbruck, 6020, Austria
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Guillemot J, Asensio V, Bordron B, Nouvellon Y, le Maire G, Bouillet JP, Domec JC, Delgado Rojas JS, Abreu-Junior CH, Battie-Laclau P, Cornut I, Germon A, De Moraes Gonçalves JL, Robin A, Laclau JP. Increased hydraulic constraints in Eucalyptus plantations fertilized with potassium. Plant Cell Environ 2021; 44:2938-2950. [PMID: 34033133 DOI: 10.1111/pce.14102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 05/20/2021] [Indexed: 06/12/2023]
Abstract
Fertilization is commonly used to increase growth in forest plantations, but it may also affect tree water relations and responses to drought. Here, we measured changes in biomass, transpiration, sapwood-to-leaf area ratio (As :Al ) and sap flow driving force (ΔΨ) during the 6-year rotation of tropical plantations of Eucalyptus grandis under controlled conditions for throughfall and potassium (K) fertilization. K fertilization increased final tree height by 8 m. Throughfall exclusion scarcely affected tree functioning because of deep soil water uptake. Tree growth increased in K-supplied plots and remained stable in K-depleted plots as tree height increased, while growth per unit leaf area increased in all plots. Stand transpiration and hydraulic conductance standardized per leaf area increased with height in K-depleted plots, but remained stable or decreased in K-supplied plots. Greater Al in K-supplied plots increased the hydraulic constraints on water use. This involved a direct mechanism through halved As :Al in K-supplied plots relative to K-depleted plots, and an indirect mechanism through deteriorated water status in K-supplied plots, which prevented the increase in ΔΨ with tree height. K fertilization in tropical plantations reduces the hydraulic compensation to growth, which could increase the risk of drought-induced dieback under climate change.
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Affiliation(s)
- Joannès Guillemot
- CIRAD, UMR Eco&Sols, Montpellier, France
- Eco&Sols, Univ Montpellier, CIRAD, INRAe, IRD, Montpellier SupAgro, Montpellier, France
- Department of Forest Sciences, Universidade de São Paulo, "Luiz de Queiroz" College of Agriculture (USP-ESALQ), Piracicaba, Brazil
| | - Verónica Asensio
- Department of Forest Sciences, Universidade de São Paulo, "Luiz de Queiroz" College of Agriculture (USP-ESALQ), Piracicaba, Brazil
- Center of Nuclear Energy in Agriculture, Universidade de São Paulo (USP-CENA), Piracicaba, Brazil
- Edafotec SL, Vigo, Spain
| | - Bruno Bordron
- CIRAD, UMR Eco&Sols, Montpellier, France
- Eco&Sols, Univ Montpellier, CIRAD, INRAe, IRD, Montpellier SupAgro, Montpellier, France
- Department of Forest Sciences, Universidade de São Paulo, "Luiz de Queiroz" College of Agriculture (USP-ESALQ), Piracicaba, Brazil
| | - Yann Nouvellon
- CIRAD, UMR Eco&Sols, Montpellier, France
- Eco&Sols, Univ Montpellier, CIRAD, INRAe, IRD, Montpellier SupAgro, Montpellier, France
- Department of Forest Sciences, Universidade de São Paulo, "Luiz de Queiroz" College of Agriculture (USP-ESALQ), Piracicaba, Brazil
| | - Guerric le Maire
- CIRAD, UMR Eco&Sols, Montpellier, France
- Eco&Sols, Univ Montpellier, CIRAD, INRAe, IRD, Montpellier SupAgro, Montpellier, France
- NIPE, UNICAMP, Campinas, Brazil
| | - Jean-Pierre Bouillet
- CIRAD, UMR Eco&Sols, Montpellier, France
- Eco&Sols, Univ Montpellier, CIRAD, INRAe, IRD, Montpellier SupAgro, Montpellier, France
- Department of Forest Sciences, Universidade de São Paulo, "Luiz de Queiroz" College of Agriculture (USP-ESALQ), Piracicaba, Brazil
| | - Jean-Christophe Domec
- Bordeaux Sciences Agro, UMR INRAe-ISPA 1391, Gradignan, France
- Nicholas School of the Environment, Duke University, Durham, North Carolina, USA
| | - Juan Sinforiano Delgado Rojas
- Department of Forest Sciences, Universidade de São Paulo, "Luiz de Queiroz" College of Agriculture (USP-ESALQ), Piracicaba, Brazil
| | | | - Patricia Battie-Laclau
- Department of Forest Sciences, Universidade de São Paulo, "Luiz de Queiroz" College of Agriculture (USP-ESALQ), Piracicaba, Brazil
- Center of Nuclear Energy in Agriculture, Universidade de São Paulo (USP-CENA), Piracicaba, Brazil
| | - Ivan Cornut
- CIRAD, UMR Eco&Sols, Montpellier, France
- Eco&Sols, Univ Montpellier, CIRAD, INRAe, IRD, Montpellier SupAgro, Montpellier, France
- Ecologie Systématique Evolution, Univ. Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, Orsay, France
| | - Amandine Germon
- CIRAD, UMR Eco&Sols, Montpellier, France
- Eco&Sols, Univ Montpellier, CIRAD, INRAe, IRD, Montpellier SupAgro, Montpellier, France
- School of Agricultural Sciences, UNESP-São Paulo State University, Botucatu, Brazil
| | | | - Agnès Robin
- CIRAD, UMR Eco&Sols, Montpellier, France
- Eco&Sols, Univ Montpellier, CIRAD, INRAe, IRD, Montpellier SupAgro, Montpellier, France
- Department of Forest Sciences, Universidade de São Paulo, "Luiz de Queiroz" College of Agriculture (USP-ESALQ), Piracicaba, Brazil
- School of Agricultural Sciences, UNESP-São Paulo State University, Botucatu, Brazil
| | - Jean-Paul Laclau
- CIRAD, UMR Eco&Sols, Montpellier, France
- Eco&Sols, Univ Montpellier, CIRAD, INRAe, IRD, Montpellier SupAgro, Montpellier, France
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20
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Mrad A, Johnson DM, Love DM, Domec JC. The roles of conduit redundancy and connectivity in xylem hydraulic functions. New Phytol 2021; 231:996-1007. [PMID: 33908055 DOI: 10.1111/nph.17429] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 04/20/2021] [Indexed: 06/12/2023]
Abstract
Wood anatomical traits shape a xylem segment's hydraulic efficiency and resistance to embolism spread due to declining water potential. It has been known for decades that variations in conduit connectivity play a role in altering xylem hydraulics. However, evaluating the precise effect of conduit connectivity has been elusive. The objective here is to establish an analytical linkage between conduit connectivity and grouping and tissue-scale hydraulics. It is hypothesized that an increase in conduit connectivity brings improved resistance to embolism spread due to increased hydraulic pathway redundancy. However, an increase in conduit connectivity could also reduce resistance due to increased speed of embolism spread with respect to pressure. We elaborate on this trade-off using graph theory, percolation theory and computational modeling of xylem. The results are validated using anatomical measurements of Acer branch xylem. Considering only species with vessels, increases in connectivity improve resistance to embolism spread without negatively affecting hydraulic conductivity. The often measured grouping index fails to capture the totality of the effect of conduit connectivity on xylem hydraulics. Variations in xylem network characteristics, such as conduit connectivity, might explain why hypothesized trends among woody species, such as the 'safety-efficiency' trade-off hypothesis, are weaker than expected.
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Affiliation(s)
- Assaad Mrad
- Nicholas School of the Environment, Duke University, Durham, NC, 27708, USA
- Department of Civil and Environmental Engineering, University of California, Irvine, CA, 92697, USA
- Department of Engineering, Wake Forest University, Winston-Salem, NC, 27101, USA
| | - Daniel M Johnson
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, 30602, USA
| | - David M Love
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, 30602, USA
| | - Jean-Christophe Domec
- Nicholas School of the Environment, Duke University, Durham, NC, 27708, USA
- Bordeaux Sciences Agro, UMR 1391 INRA-ISPA, Gradignan Cedex, 33175, France
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21
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Nadal M, Brodribb TJ, Fernández-Marín B, García-Plazaola JI, Arzac MI, López-Pozo M, Perera-Castro AV, Gulías J, Flexas J, Farrant JM. Differences in biochemical, gas exchange and hydraulic response to water stress in desiccation tolerant and sensitive fronds of the fern Anemia caffrorum. New Phytol 2021; 231:1415-1430. [PMID: 33959976 DOI: 10.1111/nph.17445] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Accepted: 04/23/2021] [Indexed: 06/12/2023]
Abstract
Desiccation tolerant plants can survive extreme water loss in their vegetative tissues. The fern Anemia caffrorum produces desiccation tolerant (DT) fronds in the dry season and desiccation sensitive (DS) fronds in the wet season, providing a unique opportunity to explore the physiological mechanisms associated with desiccation tolerance. Anemia caffrorum plants with either DT or DS fronds were acclimated in growth chambers. Photosynthesis, frond structure and anatomy, water relations and minimum conductance to water vapour were measured under well-watered conditions. Photosynthesis, hydraulics, frond pigments, antioxidants and abscisic acid contents were monitored under water deficit. A comparison between DT and DS fronds under well-watered conditions showed that the former presented higher leaf mass per area, minimum conductance, tissue elasticity and lower CO2 assimilation. Water deficit resulted in a similar induction of abscisic acid in both frond types, but DT fronds maintained higher stomatal conductance and upregulated more prominently lipophilic antioxidants. The seasonal alternation in production of DT and DS fronds in A. caffrorum represents a mechanism by which carbon gain can be maximized during the rainy season, and a greater investment in protective mechanisms occurs during the hot dry season, enabling the exploitation of episodic water availability.
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Affiliation(s)
- Miquel Nadal
- Research Group on Plant Biology under Mediterranean Conditions, Departament de Biologia, Universitat de les Illes Balears (UIB), INAGEA, Carretera de Valldemossa Km 7.5, Palma de Mallorca, Illes Balears, 07122, Spain
| | - Tim J Brodribb
- School of Natural Sciences, University of Tasmania, Hobart, Tas., 7001, Australia
| | - Beatriz Fernández-Marín
- Department of Botany, Ecology and Plant Physiology, University of La Laguna (ULL), Tenerife, 38200, Spain
- Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, Leioa, 48940, Spain
| | - José I García-Plazaola
- Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, Leioa, 48940, Spain
| | - Miren I Arzac
- Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, Leioa, 48940, Spain
| | - Marina López-Pozo
- Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, Leioa, 48940, Spain
| | - Alicia V Perera-Castro
- Research Group on Plant Biology under Mediterranean Conditions, Departament de Biologia, Universitat de les Illes Balears (UIB), INAGEA, Carretera de Valldemossa Km 7.5, Palma de Mallorca, Illes Balears, 07122, Spain
| | - Javier Gulías
- Research Group on Plant Biology under Mediterranean Conditions, Departament de Biologia, Universitat de les Illes Balears (UIB), INAGEA, Carretera de Valldemossa Km 7.5, Palma de Mallorca, Illes Balears, 07122, Spain
| | - Jaume Flexas
- Research Group on Plant Biology under Mediterranean Conditions, Departament de Biologia, Universitat de les Illes Balears (UIB), INAGEA, Carretera de Valldemossa Km 7.5, Palma de Mallorca, Illes Balears, 07122, Spain
- King Abdulaziz University, Jeddah, 80200, Saudi Arabia
| | - Jill M Farrant
- Department of Molecular and Cell Biology, University of Cape Town, Private Bag X3, Rondebosch, 7701, South Africa
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22
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Gleason SM, Nalezny L, Hunter C, Bensen R, Chintamanani S, Comas LH. Growth and grain yield of eight maize hybrids are aligned with water transport, stomatal conductance, and photosynthesis in a semi-arid irrigated system. Physiol Plant 2021; 172:1941-1949. [PMID: 33749003 DOI: 10.1111/ppl.13400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 03/04/2021] [Accepted: 03/19/2021] [Indexed: 06/12/2023]
Abstract
There is increasing interest in understanding how trait networks can be manipulated to improve the performance of crop species. Working towards this goal, we have identified key traits linking the acquisition of water, the transport of water to the sites of evaporation and photosynthesis, stomatal conductance, and growth across eight maize hybrid lines grown under well-watered and water-limiting conditions in Northern Colorado. Under well-watered conditions, hybrids with higher end-of-season growth and grain yield exhibited higher leaf-specific conductance, lower operating water potentials, higher rates of midday stomatal conductance, higher rates of net CO2 assimilation, and greater leaf osmotic adjustment. This trait network was similar under water-limited conditions with the notable exception that linkages between water transport, midday stomatal conductance, and growth were even stronger than under fully watered conditions. The maintenance of high leaf-specific conductance throughout the day was achieved via higher maximal conductance rates rather than lower susceptibility to conductance loss. Our results suggest that efforts to improve maize performance in well-watered and water-limiting conditions would benefit from considering the physiological trait networks governing water and carbon flux rather than focusing on single traits independently of one another.
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Affiliation(s)
- Sean M Gleason
- Water Management and Systems Research Unit, United States Department of Agriculture, Agricultural Research Service, Fort Collins, Colorado, USA
- Department of Biology, Colorado State University, Fort Collins, Colorado, USA
| | - Lauren Nalezny
- Water Management and Systems Research Unit, United States Department of Agriculture, Agricultural Research Service, Fort Collins, Colorado, USA
| | - Cameron Hunter
- Water Management and Systems Research Unit, United States Department of Agriculture, Agricultural Research Service, Fort Collins, Colorado, USA
- Department of Biology, Colorado State University, Fort Collins, Colorado, USA
| | - Robert Bensen
- Syngenta Biotechnology Inc., Stanton, Minnesota, USA
| | | | - Louise H Comas
- Water Management and Systems Research Unit, United States Department of Agriculture, Agricultural Research Service, Fort Collins, Colorado, USA
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23
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Wang YQ, Ni MY, Zeng WH, Huang DL, Xiang W, He PC, Ye Q, Cao KF, Zhu SD. Co-ordination between leaf biomechanical resistance and hydraulic safety across 30 sub-tropical woody species. Ann Bot 2021; 128:183-191. [PMID: 33930116 PMCID: PMC8324032 DOI: 10.1093/aob/mcab055] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 04/24/2021] [Indexed: 05/28/2023]
Abstract
BACKGROUND AND AIMS Leaf biomechanical resistance protects leaves from biotic and abiotic damage. Previous studies have revealed that enhancing leaf biomechanical resistance is costly for plant species and leads to an increase in leaf drought tolerance. We thus predicted that there is a functional correlation between leaf hydraulic safety and biomechanical characteristics. METHODS We measured leaf morphological and anatomical traits, pressure-volume parameters, maximum leaf hydraulic conductance (Kleaf-max), leaf water potential at 50 % loss of hydraulic conductance (P50leaf), leaf hydraulic safety margin (SMleaf), and leaf force to tear (Ft) and punch (Fp) of 30 co-occurring woody species in a sub-tropical evergreen broadleaved forest. Linear regression analysis was performed to examine the relationships between biomechanical resistance and other leaf hydraulic traits. KEY RESULTS We found that higher Ft and Fp values were significantly associated with a lower (more negative) P50leaf and a larger SMleaf, thereby confirming the correlation between leaf biomechanical resistance and hydraulic safety. However, leaf biomechanical resistance showed no correlation with Kleaf-max, although it was significantly and negatively correlated with leaf outside-xylem hydraulic conductance. In addition, we also found that there was a significant correlation between biomechanical resistance and the modulus of elasticity by excluding an outlier. CONCLUSIONS The findings of this study reveal leaf biomechanical-hydraulic safety correlation in sub-tropical woody species.
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Affiliation(s)
- Yong-Qiang Wang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Key Laboratory of Forest Ecology and Conservation, Guangxi University, Nanning, Guangxi, China
| | - Ming-Yuan Ni
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Key Laboratory of Forest Ecology and Conservation, Guangxi University, Nanning, Guangxi, China
| | - Wen-Hao Zeng
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Key Laboratory of Forest Ecology and Conservation, Guangxi University, Nanning, Guangxi, China
| | - Dong-Liu Huang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Key Laboratory of Forest Ecology and Conservation, Guangxi University, Nanning, Guangxi, China
| | - Wei Xiang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Key Laboratory of Forest Ecology and Conservation, Guangxi University, Nanning, Guangxi, China
| | - Peng-Cheng He
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, Guangdong, China
| | - Qing Ye
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, Guangdong, China
| | - Kun-Fang Cao
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Key Laboratory of Forest Ecology and Conservation, Guangxi University, Nanning, Guangxi, China
| | - Shi-Dan Zhu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Key Laboratory of Forest Ecology and Conservation, Guangxi University, Nanning, Guangxi, China
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Słupianek A, Dolzblasz A, Sokołowska K. Xylem Parenchyma-Role and Relevance in Wood Functioning in Trees. Plants (Basel) 2021; 10:1247. [PMID: 34205276 PMCID: PMC8235782 DOI: 10.3390/plants10061247] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 06/11/2021] [Accepted: 06/16/2021] [Indexed: 12/11/2022]
Abstract
Woody plants are characterised by a highly complex vascular system, wherein the secondary xylem (wood) is responsible for the axial transport of water and various substances. Previous studies have focused on the dead conductive elements in this heterogeneous tissue. However, the living xylem parenchyma cells, which constitute a significant functional fraction of the wood tissue, have been strongly neglected in studies on tree biology. Although there has recently been increased research interest in xylem parenchyma cells, the mechanisms that operate in these cells are poorly understood. Therefore, the present review focuses on selected roles of xylem parenchyma and its relevance in wood functioning. In addition, to elucidate the importance of xylem parenchyma, we have compiled evidence supporting the hypothesis on the significance of parenchyma cells in tree functioning and identified the key unaddressed questions in the field.
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Affiliation(s)
- Aleksandra Słupianek
- Department of Plant Developmental Biology, Faculty of Biological Sciences, University of Wrocław, Kanonia 6/8, 50-328 Wrocław, Poland; (A.D.); (K.S.)
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25
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Castillo-Argaez R, Vazquez A, Konkol JL, Vargas AI, Ploetz RC, Etxeberria E, Schaffer B. Sap flow, xylem anatomy and photosynthetic variables of three Persea species in response to laurel wilt. Tree Physiol 2021; 41:1004-1018. [PMID: 33079164 DOI: 10.1093/treephys/tpaa137] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 08/31/2020] [Accepted: 10/08/2020] [Indexed: 06/11/2023]
Abstract
Laurel wilt, a lethal vascular wilt disease caused by the fungus Raffaelea lauricola, affects several tree species in the Lauraceae, including three Persea species. The susceptibility to laurel wilt of two forest tree species native to the southern USA, Persea borbonia and Persea palustris, [(Raf.) Sarg.] and avocado, Persea americana (Mill.) cv Waldin, was examined and related to tree physiology and xylem anatomy. Net CO2 assimilation (A), stomatal conductance (gs), leaf chlorophyll index (LCI), leaf chlorophyll fluorescence (Fv/Fm), xylem sap flow, theoretical stem hydraulic conductivity (Kh) and xylem vessel anatomy were assessed in trees of each species that were inoculated with R. lauricola and in control trees. Laurel wilt caused a reduction in A, gs, LCI, Fv/Fm and blockage of xylem vessels by tyloses formation that negatively impacted Kh and sap flow in all Persea species. However, disease susceptibility as indicated by canopy wilting and sapwood discoloration was less pronounced in P. americana cv Waldin than in the two forest species. Xylem vessel diameter was significantly smaller in P. borbonia and P. palustris than in P. americana cv Waldin. Differences in laurel wilt susceptibility among species appear to be influenced by physiological and anatomical tree responses.
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Affiliation(s)
- Raiza Castillo-Argaez
- Tropical Research and Education Center, University of Florida, 18905 S.W. 280th Street, Homestead, FL 33031, USA
| | - Aime Vazquez
- USDA, ARS, Subtropical Horticulture Research Station, 13601 Old Cutler Road, Miami, FL 33158, USA
| | - Joshua L Konkol
- Department of Plant Pathology, University of Florida, 2550 Hull Road, PO Box 110680, Gainesville, FL 32611, USA
| | - Ana I Vargas
- Tropical Research and Education Center, University of Florida, 18905 S.W. 280th Street, Homestead, FL 33031, USA
| | - Randy C Ploetz
- Tropical Research and Education Center, University of Florida, 18905 S.W. 280th Street, Homestead, FL 33031, USA
| | - Edgardo Etxeberria
- Citrus Research and Education Center, University of Florida, 700 Experiment Station Road, Lake Alfred, FL 33850, USA
| | - Bruce Schaffer
- Tropical Research and Education Center, University of Florida, 18905 S.W. 280th Street, Homestead, FL 33031, USA
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26
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Guzmán-Delgado P, Laca E, Zwieniecki MA. Unravelling foliar water uptake pathways: The contribution of stomata and the cuticle. Plant Cell Environ 2021; 44:1728-1740. [PMID: 33665817 DOI: 10.1111/pce.14041] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Revised: 02/26/2021] [Accepted: 03/01/2021] [Indexed: 06/12/2023]
Abstract
Plants can absorb water through their leaf surfaces, a phenomenon commonly referred to as foliar water uptake (FWU). Despite the physiological importance of FWU, the pathways and mechanisms underlying the process are not well known. Using a novel experimental approach, we parsed out the contribution of the stomata and the cuticle to FWU in two species with Mediterranean (Prunus dulcis) and temperate (Pyrus communis) origin. The hydraulic parameters of FWU were derived by analysing mass and water potential changes of leaves placed in a fog chamber. Leaves were previously treated with abscisic acid to force stomata to remain closed, with fusicoccin to remain open, and with water (control). Leaves with open stomata rehydrated two times faster than leaves with closed stomata and attained approximately three times higher maximum fluxes and hydraulic conductance. Based on FWU rates, we propose that rehydration through stomata occurs primarily via diffusion of water vapour rather than in liquid form even when leaf surfaces are covered with a water film. We discuss the potential mechanisms of FWU and the significance of both stomatal and cuticular pathways for plant productivity and survival.
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Affiliation(s)
- Paula Guzmán-Delgado
- Department of Plant Sciences, University of California Davis, Davis, California, USA
| | - Emilio Laca
- Department of Plant Sciences, University of California Davis, Davis, California, USA
| | - Maciej A Zwieniecki
- Department of Plant Sciences, University of California Davis, Davis, California, USA
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27
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Tan X, Liu M, Du N, Zwiazek JJ. Ethylene enhances root water transport and aquaporin expression in trembling aspen (Populus tremuloides) exposed to root hypoxia. BMC Plant Biol 2021; 21:227. [PMID: 34020594 PMCID: PMC8140438 DOI: 10.1186/s12870-021-02995-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 04/26/2021] [Indexed: 05/31/2023]
Abstract
BACKGROUND Root hypoxia has detrimental effects on physiological processes and growth in most plants. The effects of hypoxia can be partly alleviated by ethylene. However, the tolerance mechanisms contributing to the ethylene-mediated hypoxia tolerance in plants remain poorly understood. RESULTS In this study, we examined the effects of root hypoxia and exogenous ethylene treatments on leaf gas exchange, root hydraulic conductance, and the expression levels of several aquaporins of the plasma membrane intrinsic protein group (PIP) in trembling aspen (Populus tremuloides) seedlings. Ethylene enhanced net photosynthetic rates, transpiration rates, and root hydraulic conductance in hypoxic plants. Of the two subgroups of PIPs (PIP1 and PIP2), the protein abundance of PIP2s and the transcript abundance of PIP2;4 and PIP2;5 were higher in ethylene-treated trembling aspen roots compared with non-treated roots under hypoxia. The increases in the expression levels of these aquaporins could potentially facilitate root water transport. The enhanced root water transport by ethylene was likely responsible for the increase in leaf gas exchange of the hypoxic plants. CONCLUSIONS Exogenous ethylene enhanced root water transport and the expression levels of PIP2;4 and PIP2;5 in hypoxic roots of trembling aspen. The results suggest that ethylene facilitates the aquaporin-mediated water transport in plants exposed to root hypoxia.
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Affiliation(s)
- Xiangfeng Tan
- Department of Renewable Resources, University of Alberta, AB, T6G 2E3, Edmonton, Canada
- Institute of Soil and Water Resources and Environmental Science, Zhejiang University, 310058, Hangzhou, China
| | - Mengmeng Liu
- Department of Renewable Resources, University of Alberta, AB, T6G 2E3, Edmonton, Canada
| | - Ning Du
- Institute of Ecology and Biodiversity, School of Life Science, Shandong University, 266237, Qingdao, China
| | - Janusz J Zwiazek
- Department of Renewable Resources, University of Alberta, AB, T6G 2E3, Edmonton, Canada.
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28
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Long RW, Medeiros JS. Water in, water out: root form influences leaf function. New Phytol 2021; 229:1186-1188. [PMID: 33085085 DOI: 10.1111/nph.16962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Affiliation(s)
- Randall W Long
- Holden Arboretum, 9550 Sperry Rd, Kirtland, OH, 44094, USA
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29
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Cardoso AA, Visel D, Kane CN, Batz TA, García Sánchez C, Kaack L, Lamarque LJ, Wagner Y, King A, Torres-Ruiz JM, Corso D, Burlett R, Badel E, Cochard H, Delzon S, Jansen S, McAdam SAM. Drought-induced lacuna formation in the stem causes hydraulic conductance to decline before xylem embolism in Selaginella. New Phytol 2020; 227:1804-1817. [PMID: 32386326 DOI: 10.1111/nph.16649] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 04/22/2020] [Indexed: 05/25/2023]
Abstract
Lycophytes are the earliest diverging extant lineage of vascular plants, sister to all other vascular plants. Given that most species are adapted to ever-wet environments, it has been hypothesized that lycophytes, and by extension the common ancestor of all vascular plants, have few adaptations to drought. We investigated the responses to drought of key fitness-related traits such as stomatal regulation, shoot hydraulic conductance (Kshoot ) and stem xylem embolism resistance in Selaginella haematodes and S. pulcherrima, both native to tropical understory. During drought stomata in both species were found to close before declines in Kshoot , with a 50% loss of Kshoot occurring at -1.7 and -2.5 MPa in S. haematodes and S. pulcherrima, respectively. Direct observational methods revealed that the xylem of both species was resistant to embolism formation, with 50% of embolized xylem area occurring at -3.0 and -4.6 MPa in S. haematodes and S. pulcherrima, respectively. X-ray microcomputed tomography images of stems revealed that the decline in Kshoot occurred with the formation of an air-filled lacuna, disconnecting the central vascular cylinder from the cortex. We propose that embolism-resistant xylem and large capacitance, provided by collapsing inner cortical cells, is essential for Selaginella survival during water deficit.
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Affiliation(s)
- Amanda A Cardoso
- Purdue Center for Plant Biology, Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA
| | - Dominik Visel
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, Ulm, 89081, Germany
| | - Cade N Kane
- Purdue Center for Plant Biology, Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA
| | - Timothy A Batz
- Purdue Center for Plant Biology, Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA
| | - Clara García Sánchez
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, Ulm, 89081, Germany
| | - Lucian Kaack
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, Ulm, 89081, Germany
| | | | - Yael Wagner
- Department of Plant & Environmental Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Andrew King
- Synchrotron Source Optimisée de Lumière d'Energie Intermédiaire du LURE, L'Orme de Merisiers, Saint Aubin-BP48, Gif-sur-Yvette Cedex, France
| | - José M Torres-Ruiz
- INRAE, PIAF, Université Clermont-Auvergne, Clermont-Ferrand, 63000, France
| | - Déborah Corso
- INRAE, BIOGECO, University of Bordeaux, Pessac, 33615, France
| | - Régis Burlett
- INRAE, BIOGECO, University of Bordeaux, Pessac, 33615, France
| | - Eric Badel
- INRAE, PIAF, Université Clermont-Auvergne, Clermont-Ferrand, 63000, France
| | - Hervé Cochard
- INRAE, PIAF, Université Clermont-Auvergne, Clermont-Ferrand, 63000, France
| | - Sylvain Delzon
- INRAE, BIOGECO, University of Bordeaux, Pessac, 33615, France
| | - Steven Jansen
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, Ulm, 89081, Germany
| | - Scott A M McAdam
- Purdue Center for Plant Biology, Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA
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30
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Oliveira TA, Anágua-Bravo E, Aoki IV, Scaramucci T, Sobral MAP. Chemical and mechanical resistance of novel experimental hybrid coatings on dentin permeability. Microsc Res Tech 2020; 84:163-170. [PMID: 32869428 DOI: 10.1002/jemt.23574] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 07/22/2020] [Accepted: 07/31/2020] [Indexed: 11/06/2022]
Abstract
This study aimed to evaluate the capacity of novel experimental hybrid coatings (HC) to reduce dentin permeability and to verify their resistance to erosive and abrasive challenges. Dentin disc specimens (1 mm thick) were treated with 0.5 M EDTA solution and randomly allocated into three experimental groups (n = 10): Control (Saliva); Concentrated Hybrid Coating (TEOS/GPTMS/Y-APS); and Diluted Hybrid Coating (1:3 ratio with distilled water). Dentin permeability was assessed by hydraulic conductance in the following experimental time periods: post-EDTA, post treatment, post erosion (5 min in 0.05 M citric acid solution, pH = 3.8), and post abrasion (toothbrushing for 3,900 cycles). Dentin permeability percent was calculated with respect the values of post-EDTA for each experimental time. The morphology of the surface of extra dentin specimens was examined by scanning electron microscopy (SEM) in the same time periods (n = 3). Permeability data were analyzed by two-way repeated measures ANOVA and Tukey tests (p < .05). Both HC presented significantly lower dentin permeability than control post treatment and post erosion (p < .05), without difference between them (p > .05). Post abrasion, there were no significant difference among groups (p > .05). Post treatment and post erosion, the HC seemed to flow into the tubules, occluding them, while the tubules in control remained opened. Post abrasion, the tubules appear to be occluded in all groups. In conclusion, the experimental hybrid coatings were capable of reducing dentin permeability after treatment. They were also able to resist to erosive and abrasive challenges, with the advantage of forming thinner and colorless films that can be potentially used to treat dentin hypersensitivity.
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Affiliation(s)
- Tatiane Alexandre Oliveira
- Department of Restorative Dentistry, School of Dentistry, University of São Paulo, São Paulo, SP, Brazil
| | - Ernesto Anágua-Bravo
- Department of Chemical Engineering, Polytechnic School, University of São Paulo, São Paulo, SP, Brazil
| | - Idalina Vieira Aoki
- Department of Chemical Engineering, Polytechnic School, University of São Paulo, São Paulo, SP, Brazil
| | - Taís Scaramucci
- Department of Restorative Dentistry, School of Dentistry, University of São Paulo, São Paulo, SP, Brazil
| | - Maria Angela Pita Sobral
- Department of Restorative Dentistry, School of Dentistry, University of São Paulo, São Paulo, SP, Brazil
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Cardoso AA, Billon LM, Fanton Borges A, Fernández-de-Uña L, Gersony JT, Güney A, Johnson KM, Lemaire C, Mrad A, Wagner Y, Petit G. New developments in understanding plant water transport under drought stress. New Phytol 2020; 227:1025-1027. [PMID: 32662102 DOI: 10.1111/nph.16663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Affiliation(s)
- Amanda A Cardoso
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA
| | - Lise-Marie Billon
- Université Clermont Auvergne, INRAE, PIAF, 63000, Clermont-Ferrand, France
| | - Ana Fanton Borges
- Yale School of Forestry and Environmental Studies, Yale University, 195 Prospect Street, New Haven, CT, 06511, USA
| | | | - Jess T Gersony
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Aylin Güney
- Institute of Botany, University of Hohenheim, Garbenstr 30, D-70599, Stuttgart, Germany
- Department of Biology, Faculty of Science, Akdeniz University, 07058, Antalya, Turkey
| | - Kate M Johnson
- Biological Sciences, School of Natural Sciences, University of Tasmania, Hobart, TAS, Australia
| | - Cédric Lemaire
- Université Clermont Auvergne, INRAE, PIAF, 63000, Clermont-Ferrand, France
| | - Assaad Mrad
- Nicholas School of the Environment, Duke University, Durham, NC, 27708, USA
| | - Yael Wagner
- Department of Plant & Environmental Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Giai Petit
- Department TeSAF, Università degli Studi di Padova, Viale dell'Università 16, 35020, Legnaro, Italy
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32
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Bourbia I, Carins-Murphy MR, Gracie A, Brodribb TJ. Xylem cavitation isolates leaky flowers during water stress in pyrethrum. New Phytol 2020; 227:146-155. [PMID: 32130731 DOI: 10.1111/nph.16516] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 02/20/2020] [Indexed: 06/10/2023]
Abstract
Flowers underpin plant evolution, genetic legacy and global food supply. They are exposed to similar evaporative conditions as leaves, yet floral physiology is a product of different selective forces. We used Tanacetum cinerariifolium, a perennial daisy, to examine the response of flowers to whole-plant water stress, determining if flowers constitute a liability during drought, and how this species has adapted to minimize risk associated with reproduction. We determined the relative transpiration cost of flowers and leaves and confirmed that flowers in this species are xylem-hydrated. The relative water stress tolerance of leaves and flowers then was compared using xylem vulnerability measurements linked with observed tissue damage during an acute drought treatment. Flowers were a major source of water loss during drought but the xylem supplying them was much more vulnerable to cavitation than leaves. This xylem vulnerability segmentation was confirmed by observations that most flowers died whereas leaves were minimally affected during drought. Early cavitation and hydraulic isolation of flowers during drought benefits the plant by slowing the dehydration of perennial vegetative organs and delaying systemic xylem damage. Our results highlight the need to understand flower xylem vulnerability as a means of predicting plant reproductive failure under future drought.
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Affiliation(s)
- Ibrahim Bourbia
- School of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, Tas., 7001, Australia
| | - Madeline R Carins-Murphy
- School of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, Tas., 7001, Australia
| | - Alistair Gracie
- Tasmania Institute of Agriculture, University of Tasmania, Private Bag 54, Hobart, Tas., 7001, Australia
| | - Timothy J Brodribb
- School of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, Tas., 7001, Australia
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33
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Jiang P, Meinzer FC, Wang H, Kou L, Dai X, Fu X. Below-ground determinants and ecological implications of shrub species' degree of isohydry in subtropical pine plantations. New Phytol 2020; 226:1656-1666. [PMID: 32096212 DOI: 10.1111/nph.16502] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 02/16/2020] [Indexed: 06/10/2023]
Abstract
The degree of plant iso/anisohydry is a popular framework for characterising species-specific drought responses. However, we know little about associations between below-ground and above-ground hydraulic traits as well as the broader ecological implications of this framework. For 24 understory shrub species in seasonally dry subtropical coniferous plantations, we investigated contributions of the degree of isohydry to species' resource economy strategies, abundance, and importance value, and quantified the hydraulic conductance (Kh ) of above-ground and below-ground organs, magnitude of deep water acquisition (WAdeep ), shallow absorptive root traits (diameter, specific root length, tissue density), and resource-use efficiencies (Amax , maximum photosynthesis rate; PNUE, photosynthetic nitrogen-use efficiency). The extreme isohydric understory species had lower wood density (a proxy for higher growth rates) because their higher WAdeep and whole-plant Kh allowed higher Amax and PNUE, and thus did not necessarily show lower abundance and importance values. Although species' Kh was coordinated with their water foraging capacity in shallow soil, the more acquisitive deep roots were more crucial than shallow roots in shaping species' extreme isohydric behaviour. Our results provide new insights into the mechanisms through which below-ground hydraulic traits, especially those of deep roots, determine species' degree of isohydry and economic strategies.
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Affiliation(s)
- Peipei Jiang
- Qianyanzhou Ecological Research Station, Key Laboratory of Ecosystem Network Observation and Modelling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Frederick C Meinzer
- USDA Forest Service, Pacific Northwest Research Station, 3200 SW Jefferson Way, Corvallis, OR, 97331, USA
| | - Huimin Wang
- Qianyanzhou Ecological Research Station, Key Laboratory of Ecosystem Network Observation and Modelling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Liang Kou
- Qianyanzhou Ecological Research Station, Key Laboratory of Ecosystem Network Observation and Modelling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Xiaoqin Dai
- Qianyanzhou Ecological Research Station, Key Laboratory of Ecosystem Network Observation and Modelling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Xiaoli Fu
- Qianyanzhou Ecological Research Station, Key Laboratory of Ecosystem Network Observation and Modelling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100190, China
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Puértolas J, Pardos M, de Ollas C, Albacete A, Dodd IC. Soil moisture heterogeneity regulates water use in Populus nigra L. by altering root and xylem sap phytohormone concentrations. Tree Physiol 2020; 40:762-773. [PMID: 32193548 DOI: 10.1093/treephys/tpaa037] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 03/09/2020] [Accepted: 03/18/2020] [Indexed: 06/10/2023]
Abstract
Soil moisture heterogeneity in the root zone is common both during the establishment of tree seedlings and in experiments aiming to impose semi-constant soil moisture deficits, but its effects on regulating plant water use compared with homogenous soil drying are not well known in trees. Pronounced vertical soil moisture heterogeneity was imposed on black poplar (Populus nigra L.) grown in soil columns by altering irrigation frequency, to test whether plant water use, hydraulic responses, root phytohormone concentrations and root xylem sap chemical composition differed between wet (well-watered, WW), and homogeneously (infrequent deficit irrigation, IDI) and heterogeneously dry soil (frequent deficit irrigation, FDI). At the same bulk soil water content, FDI plants had greater water use than IDI plants, probably because root abscisic acid (ABA) concentration was low in the upper wetter layer of FDI plants, which maintained root xylem sap ABA concentration at basal levels in contrast with IDI. Soil drying did not increase root xylem concentration of any other hormone. Nevertheless, plant-to-plant variation in xylem jasmonic acid (JA) concentration was negatively related to leaf stomatal conductance within WW and FDI plants. However, feeding detached leaves with high (1200 nM) JA concentrations via the transpiration stream decreased transpiration only marginally. Xylem pH and sulphate concentration decreased in FDI plants compared with well-watered plants. Frequent deficit irrigation increased root accumulation of the cytokinin trans-zeatin (tZ), especially in the dry lower layer, and of the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC), in the wet upper soil layer. Root hormone accumulation might explain the maintenance of high root hydraulic conductance and water use in FDI plants (similar to well-watered plants) compared with IDI plants. In irrigated tree crops, growers could vary irrigation scheduling to control water use by altering the hormone balance.
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Affiliation(s)
- Jaime Puértolas
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK
| | - Marta Pardos
- Centro de Investigación Forestal (CIFOR), Instituto Nacional de Investigación Agraria y Alimentaria (INIA), Crta A Coruña s/n, Madrid E-28040, Spain
| | - Carlos de Ollas
- Departamento de Ciencias Agrarias y del Medio Natural, Universitat Jaume I, Campus Riu Sec, Castelló de la Plana E-12071, Spain
| | - Alfonso Albacete
- Departamento de Nutrición Vegetal, Centro de Edafología y Biología Aplicada del Segura (CEBAS), Consejo Nacional de Investigaciones Científicas (CSIC), Campus Universitario de Espinardo, Espinardo, Murcia E-30100, Spain
- Departamento de Producción Vegetal y Agrotecnologýa, Instituto Murciano de Investigación y Desarrollo Agrario y Alimentario (IMIDA), C/Mayor s/n, La Alberca, Murcia E-30150, Spain
| | - Ian C Dodd
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK
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35
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Richardson F, Jordan GJ, Brodribb TJ. Leaf hydraulic conductance is linked to leaf symmetry in bifacial, amphistomatic leaves of sunflower. J Exp Bot 2020; 71:2808-2816. [PMID: 31970417 PMCID: PMC7210757 DOI: 10.1093/jxb/eraa035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 01/21/2020] [Indexed: 05/14/2023]
Abstract
The hydraulic implications of stomatal positioning across leaf surfaces and the impact on internal water flow through amphistomatic leaves are not currently well understood. Amphistomaty potentially provides hydraulic efficiencies if the majority of hydraulic resistance in the leaf exists outside the xylem in the mesophyll. Such a scenario would mean that the same xylem network could equally supply a hypostomatic or amphistomatic leaf. Here we examine leaves of Helianthus annuus to determine whether amphistomaty in this species is associated with higher hydraulic efficiency compared with hypostomatic leaves. We identified asymmetry in the positioning of minor veins which were significantly closer to the abaxial than the adaxial leaf surface, combined with lower Kleaf when transpiration was driven through the adaxial rather than the abaxial surface. We also identified a degree of coordination in stomatal behaviour driven by leaf hydraulics, where the hydraulic conditions experienced by an individual leaf surface affected the stomatal behaviour on the opposite surface. We found no advantage to amphistomaty based on efficiencies in construction costs of the venous system, represented by vein density:stomatal density, only limited hydraulic independence between leaf surfaces. These results suggest that amphistomaty does not substantially increase whole-leaf hydraulic efficiency.
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Affiliation(s)
- Freya Richardson
- School of Natural Sciences, University of Tasmania, Hobart, Tasmania, Australia
| | - Gregory J Jordan
- School of Natural Sciences, University of Tasmania, Hobart, Tasmania, Australia
| | - Timothy J Brodribb
- School of Natural Sciences, University of Tasmania, Hobart, Tasmania, Australia
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36
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Corso D, Delzon S, Lamarque LJ, Cochard H, Torres-Ruiz JM, King A, Brodribb T. Neither xylem collapse, cavitation, or changing leaf conductance drive stomatal closure in wheat. Plant Cell Environ 2020; 43:854-865. [PMID: 31953855 DOI: 10.1111/pce.13722] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 01/06/2020] [Accepted: 01/09/2020] [Indexed: 05/24/2023]
Abstract
Identifying the drivers of stomatal closure and leaf damage during stress in grasses is a critical prerequisite for understanding crop resilience. Here, we investigated whether changes in stomatal conductance (gs ) during dehydration were associated with changes in leaf hydraulic conductance (Kleaf ), xylem cavitation, xylem collapse, and leaf cell turgor in wheat (Triticum aestivum). During soil dehydration, the decline of gs was concomitant with declining Kleaf under mild water stress. This early decline of leaf hydraulic conductance was not driven by cavitation, as the first cavitation events in leaf and stem were detected well after Kleaf had declined. Xylem vessel deformation could only account for <5% of the observed decline in leaf hydraulic conductance during dehydration. Thus, we concluded that changes in the hydraulic conductance of tissues outside the xylem were responsible for the majority of Kleaf decline during leaf dehydration in wheat. However, the contribution of leaf resistance to whole plant resistance was less than other tissues (<35% of whole plant resistance), and this proportion remained constant as plants dehydrated, indicating that Kleaf decline during water stress was not a major driver of stomatal closure.
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Affiliation(s)
- Déborah Corso
- School of Natural Sciences, University of Tasmania, Hobart, Tasmania, Australia
| | | | - Laurent J Lamarque
- BIOGECO, INRA, Univ. Bordeaux, Pessac, France
- EGFV, INRA, Univ. Bordeaux, Villenave d'Ornon, France
| | - Hervé Cochard
- INRA, PIAF, Université Clermont-Auvergne, Clermont-Ferrand, France
| | | | - Andrew King
- Synchrotron SOLEIL, L'Orme des Merisiers, Gif-sur-Yvette cedex, France
| | - Timothy Brodribb
- School of Natural Sciences, University of Tasmania, Hobart, Tasmania, Australia
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37
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Zhang H, McDowell NG, Adams HD, Wang A, Wu J, Jin C, Tian J, Zhu K, Li W, Zhang Y, Yuan F, Guan D. Divergences in hydraulic conductance and anatomical traits of stems and leaves in three temperate tree species coping with drought, N addition and their interactions. Tree Physiol 2020; 40:230-244. [PMID: 31860728 DOI: 10.1093/treephys/tpz135] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 11/18/2019] [Accepted: 12/10/2019] [Indexed: 06/10/2023]
Abstract
Drought and nitrogen (N) addition have been shown to affect tree hydraulic traits, but few studies have been made on their interactions across species with different wood types or leaf forms. We examined the responses of hydraulic conductance and xylem anatomical traits of Quercus mongolica (ring porous with simple leaves), Fraxinus mandshurica (ring porous with compound leaves) and Tilia amurensis (diffuse porous with simple leaves) to drought, N addition and their interactions. Drought stress decreased current-year xylem-specific conductivity in stems (Ksx) and leaf hydraulic conductance (Kleaf ), but N addition affected Ksx and Kleaf differently among species and watering regimes. These divergent effects were associated with different responses of anatomical traits and leaf forms. Higher mean vessel diameter in stems and lower vessel density in leaves were observed with N addition. The three-way interactive effects of drought, N addition and tree species were significant for most values of anatomical traits. These results were also reflected in large differences in vessel diameter and density among species with different wood types or leaf forms. The two-way interactive effects of drought and N addition were significant on Kleaf and predawn water potential, but not Ksx, indicating that leaves were more sensitive than stems to a combination of drought stress and N addition. Our results provide mechanistic insight into the variable responses of xylem water transport to the interactions of drought and N availability.
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Affiliation(s)
- Hongxia Zhang
- Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Nate G McDowell
- Atmospheric Sciences & Global Change, Pacific Northwest National Laboratory, Richland, WA, 99354, USA
| | - Henry D Adams
- Department of Plant Biology, Ecology and Evolution, Oklahoma State University, Stillwater, OK 74078-3013, USA
| | - Anzhi Wang
- Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China
| | - Jiabing Wu
- Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China
| | - Changjie Jin
- Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China
| | - Jinyuan Tian
- Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Kai Zhu
- Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Weibin Li
- State Key Laboratory of Grassland and Agro-ecosystems, Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730020, China
| | - Yushu Zhang
- Institute of Atmospheric Environment, China Meteorological Administration, Shenyang 110166, China
| | - Fenghui Yuan
- Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China
| | - Dexin Guan
- Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China
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38
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Chomthong M, Griffiths H. Model approaches to advance crassulacean acid metabolism system integration. Plant J 2020; 101:951-963. [PMID: 31943394 DOI: 10.1111/tpj.14691] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 01/02/2020] [Indexed: 06/10/2023]
Abstract
This review summarises recent progress in understanding crassulacean acid metabolism (CAM) systems and the integration of internal and external stimuli to maximise water-use efficiency. Complex CAM traits have been reduced to their minimum and captured as computational models, which can now be refined using recently available data from transgenic manipulations and large-scale omics studies. We identify three key areas in which an appropriate choice of modelling tool could help capture relevant comparative molecular data to address the evolutionary drivers and plasticity of CAM. One focus is to identify the environmental and internal signals that drive inverse stomatal opening at night. Secondly, it is important to identify the regulatory processes required to orchestrate the diel pattern of carbon fluxes within mesophyll layers. Finally, the limitations imposed by contrasting succulent systems and associated hydraulic conductance components should be compared in the context of water-use and evolutionary strategies. While network analysis of transcriptomic data can provide insights via co-expression modules and hubs, alternative forms of computational modelling should be used iteratively to define the physiological significance of key components and informing targeted functional gene manipulation studies. We conclude that the resultant improvements of bottom-up, mechanistic modelling systems can enhance progress towards capturing the physiological controls for phylogenetically diverse CAM systems in the face of the recent surge of information in this omics era.
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Affiliation(s)
- Methawi Chomthong
- Department of Plant Sciences, University of Cambridge, Downing street, Cambridge, CB2 3EA, UK
| | - Howard Griffiths
- Department of Plant Sciences, University of Cambridge, Downing street, Cambridge, CB2 3EA, UK
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39
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Hoppe J, Zhang X, Thomas FM. Belowground inter-ramet water transport capacity in Populus euphratica, a Central Asian desert phreatophyte. Plant Biol (Stuttg) 2020; 22:38-46. [PMID: 31507060 DOI: 10.1111/plb.13042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 09/01/2019] [Indexed: 06/10/2023]
Abstract
Populus euphratica Oliv. is a widespread phreatophytic tree species that forms riparian forests in (hyper-)arid regions of Central Asia. Its recruitment strongly relies on vegetative propagation from 'root suckers' that emerge from underground root spacers. The water transport through the spacers, although decisive for emerging ramets, has only rarely been quantified, but is crucial for the vegetative regeneration of the forests. In root spacers with different diameters collected from a mature poplar forest in northwest China, we calculated the hydraulic conductivity (kc ) from anatomical investigations on the basis of a modified Hagen-Poiseuille equation and measured it (km ) with a perfusion solution in the laboratory. The km values were compared with the water use by young and mature P. euphratica trees determined in previous studies. We obtained a significant correlation between km and kc (which, however, was higher by at least one order of magnitude). Due to the extensive occurrence of tyloses, particularly in older conduits and thicker spacers, and because the conduit area did not increase with spacer diameter, neither kc nor km increased with an increase in spacer diameter. The water supply through the spacers would be sufficient to meet the water demand even of mature trees. Our results provide a mechanistic explanation for the observed occurrence of P. euphratica clones across large areas and, provided that they are also valid for stands with larger distances to the water table, for the sustained growth and vegetative reproduction of P. euphratica stands growing at larger distances from the groundwater.
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Affiliation(s)
- J Hoppe
- Geobotany, Faculty of Regional and Environmental Sciences, University of Trier, Trier, Germany
| | - X Zhang
- Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, China
| | - F M Thomas
- Geobotany, Faculty of Regional and Environmental Sciences, University of Trier, Trier, Germany
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40
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Ruehr NK, Grote R, Mayr S, Arneth A. Beyond the extreme: recovery of carbon and water relations in woody plants following heat and drought stress. Tree Physiol 2019; 39:1285-1299. [PMID: 30924906 PMCID: PMC6703153 DOI: 10.1093/treephys/tpz032] [Citation(s) in RCA: 80] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 01/08/2019] [Accepted: 03/13/2019] [Indexed: 05/19/2023]
Abstract
Plant responses to drought and heat stress have been extensively studied, whereas post-stress recovery, which is fundamental to understanding stress resilience, has received much less attention. Here, we present a conceptual stress-recovery framework with respect to hydraulic and metabolic functioning in woody plants. We further synthesize results from controlled experimental studies following heat or drought events and highlight underlying mechanisms that drive post-stress recovery. We find that the pace of recovery differs among physiological processes. Leaf water potential and abscisic acid concentration typically recover within few days upon rewetting, while leaf gas exchange-related variables lag behind. Under increased drought severity as indicated by a loss in xylem hydraulic conductance, the time for stomatal conductance recovery increases markedly. Following heat stress release, a similar delay in leaf gas exchange recovery has been observed, but the reasons are most likely a slow reversal of photosynthetic impairment and other temperature-related leaf damages, which typically manifest at temperatures above 40 °C. Based thereon, we suggest that recovery of gas exchange is fast following mild stress, while recovery is slow and reliant on the efficiency of repair and regrowth when stress results in functional impairment and damage to critical plant processes. We further propose that increasing stress severity, particular after critical stress levels have been reached, increases the carbon cost involved in reestablishing functionality. This concept can guide future experimental research and provides a base for modeling post-stress recovery of carbon and water relations in trees.
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Affiliation(s)
- Nadine K Ruehr
- Karlsruhe Institute of Technology, Institute of Meteorology and Climate Research—Atmospheric Environmental Research (KIT/IMK-IFU), Garmisch-Partenkirchen, Germany
| | - Rüdiger Grote
- Karlsruhe Institute of Technology, Institute of Meteorology and Climate Research—Atmospheric Environmental Research (KIT/IMK-IFU), Garmisch-Partenkirchen, Germany
| | - Stefan Mayr
- Department of Botany, University of Innsbruck, Innsbruck, Austria
| | - Almut Arneth
- Karlsruhe Institute of Technology, Institute of Meteorology and Climate Research—Atmospheric Environmental Research (KIT/IMK-IFU), Garmisch-Partenkirchen, Germany
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41
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Drake PL, de Boer HJ, Schymanski SJ, Veneklaas EJ. Two sides to every leaf: water and CO 2 transport in hypostomatous and amphistomatous leaves. New Phytol 2019; 222:1179-1187. [PMID: 30570766 DOI: 10.1111/nph.15652] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 12/11/2018] [Indexed: 06/09/2023]
Abstract
Leaves with stomata on both upper and lower surfaces, termed amphistomatous, are relatively rare compared with hypostomatous leaves with stomata only on the lower surface. Amphistomaty occurs predominantly in fast-growing herbaceous annuals and in slow-growing perennial shrubs and trees. In this paper, we present the current understanding and hypotheses on the costs and benefits of amphistomaty related to water and CO2 transport in contrasting leaf morphologies. First, there is no evidence that amphistomatous species achieve higher stomatal densities on a projected leaf area basis than hypostomatous species, but two-sided gas exchange is less limited by boundary layer effects. Second, amphistomaty may provide a specific advantage in thick leaves by shortening the pathway for CO2 transport between the atmosphere and the chloroplasts. In thin leaves of fast-growing herbaceous annuals, in which both the adaxial and abaxial pathways are already short, amphistomaty enhances leaf-atmosphere gas-exchange capacity. Third, amphistomaty may help to optimise the leaf-interior water status for CO2 transport by reducing temperature gradients and so preventing the condensation of water that could limit CO2 diffusion. Fourth, a potential cost of amphistomaty is the need for additional investments in leaf water transport tissue to balance the water loss through the adaxial surface.
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Affiliation(s)
- Paul L Drake
- School of Biological Sciences, The University of Western Australia, 6009, Crawley, WA, Australia
| | - Hugo J de Boer
- Department of Environmental Sciences, Utrecht University, 3584 CS, Utrecht, the Netherlands
| | - Stanislaus J Schymanski
- Department of Environmental Systems Sciences, ETH Zurich, 8092, Zurich, Switzerland
- Department of Environmental Research and Innovation, Luxembourg Institute of Science and Technology, 4362, Esch-sur-Alzette, Luxembourg
| | - Erik J Veneklaas
- School of Biological Sciences, The University of Western Australia, 6009, Crawley, WA, Australia
- School of Agriculture and Environment, The University of Western Australia, 6009, Crawley, WA, Australia
- Institute of Agriculture, The University of Western Australia, 6009, Crawley, WA, Australia
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Korhonen A, Lehto T, Heinonen J, Repo T. Whole-plant frost hardiness of mycorrhizal (Hebeloma sp. or Suillus luteus) and non-mycorrhizal Scots pine seedlings. Tree Physiol 2019; 39:526-535. [PMID: 30371901 DOI: 10.1093/treephys/tpy105] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2017] [Revised: 07/10/2018] [Accepted: 09/02/2018] [Indexed: 05/27/2023]
Abstract
Ectomycorrhizal trees are common in the cold regions of the world, yet the role of the mycorrhizal symbiosis in plant cold tolerance is poorly known. Moreover, the standard methods for testing plant frost hardiness may not be adequate for roots and mycorrhizas. The aims of this study were to compare the frost hardiness of mycorrhizal and non-mycorrhizal Scots pine (Pinus sylvestris L.) seedlings and to test the use of reverse-flow root hydraulic conductance (Kr) measurement for root frost hardiness determination. Mycorrhizal (Hebeloma sp. or Suillus luteus) and non-mycorrhizal seedlings were grown in controlled-environment chambers for 13 weeks. After this, half of the plants were allotted to a non-hardening treatment (long day and high temperature, same as during the preceding growing season) and the other half to a hardening (short day and low temperature) 'autumn' treatment for 4 weeks. The intact seedlings were exposed to whole-plant freezing tests and the needle frost hardiness was measured by relative electrolyte leakage (REL) method. The seedlings were grown for three more weeks for visual damage assessment and Kr measurements using a high-pressure flow meter (HPFM). Mycorrhizas did not affect the frost hardiness of seedlings in either hardening treatment. The effect of the hardening treatment on frost hardiness was shown by REL and visual assessment of the aboveground parts as well as Kr of roots. Non-mycorrhizal plants were larger than mycorrhizal ones while nitrogen and phosphorus contents (per unit dry mass) were similar in all mycorrhiza treatments. In plants with no frost exposure, the non-mycorrhizal treatment had higher Kr. There was no mycorrhizal effect on plant frost hardiness when nutritional effects were excluded. Further studies are needed on the role of mycorrhizas especially in the recovery of growth and nutrient uptake in cold soils in the spring. The HPFM is useful novel method for assessment of root damage.
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Affiliation(s)
- Anna Korhonen
- Natural Resources Institute Finland (Luke), Natural Resources, PO Box 68, Joensuu, Finland
- School of Forest Sciences, University of Eastern Finland, PO Box 111, Joensuu, Finland
| | - Tarja Lehto
- School of Forest Sciences, University of Eastern Finland, PO Box 111, Joensuu, Finland
| | - Jaakko Heinonen
- Natural Resources Institute Finland (Luke), Natural Resources, PO Box 68, Joensuu, Finland
| | - Tapani Repo
- Natural Resources Institute Finland (Luke), Natural Resources, PO Box 68, Joensuu, Finland
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Liu H, Taylor SH, Xu Q, Lin Y, Hou H, Wu G, Ye Q. Life history is a key factor explaining functional trait diversity among subtropical grasses, and its influence differs between C3 and C4 species. J Exp Bot 2019; 70:1567-1580. [PMID: 30753647 PMCID: PMC6411383 DOI: 10.1093/jxb/ery462] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 01/08/2019] [Indexed: 05/04/2023]
Abstract
Life history and photosynthetic type both affect the economics of leaf physiological function. Annual plants have lower tissue densities and resource-use efficiencies than perennials, while C4 photosynthesis, facilitated in grasses by specific changes in leaf anatomy, improves photosynthetic efficiency and water-use efficiency, especially in hot climates. This study aimed to determine whether C4 photosynthesis affects differences in functional traits between annual and perennial species. We measured 26 traits and characterised niche descriptors for 42 grasses from subtropical China. Differences in the majority of traits were explained by life history. The ranges of annual species (particularly C4 annuals) extended to regions with greater temperature seasonality and lower precipitation, and annuals had less-negative turgor-loss points, higher specific leaf areas, and lower water-use efficiencies, stomatal conductances, and leaf areas per stem area than perennials. Photosynthetic type largely affected leaf physiology as expected, but interacted with life history in determining specific traits. Leaf hydraulic conductance was intermediate in perennials, highest in C4-annuals, and lowest in C3-annuals. Densities of stomata and stem vessels were similar across C3-perennials and C4 species, but stomatal densities were lower and stem vessel densities higher in C3-annuals. Phylogenetic principal component analysis confirmed that in this subtropical environment life history is the predominant axis separating species, and annuals and perennials were more different within C3 than C4 grasses. The interplay between life history and photosynthetic type may be an overlooked factor in shaping the physiological ecology of grasses.
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Affiliation(s)
- Hui Liu
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
| | - Samuel H Taylor
- Lancaster Environment Centre, Lancaster University, Lancaster, UK
| | - Qiuyuan Xu
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- College of Life Science, University of Chinese Academy of Sciences, Beijing, China
| | - Yixue Lin
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
| | - Hao Hou
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- College of Life Science, University of Chinese Academy of Sciences, Beijing, China
| | - Guilin Wu
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- College of Life Science, University of Chinese Academy of Sciences, Beijing, China
| | - Qing Ye
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
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Roddy AB, Simonin KA, McCulloh KA, Brodersen CR, Dawson TE. Water relations of Calycanthus flowers: Hydraulic conductance, capacitance, and embolism resistance. Plant Cell Environ 2018; 41:2250-2262. [PMID: 29603273 DOI: 10.1111/pce.13205] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 01/15/2018] [Accepted: 01/18/2018] [Indexed: 06/08/2023]
Abstract
For most angiosperms, producing and maintaining flowers is critical to sexual reproduction, yet little is known about the physiological processes involved in maintaining flowers throughout anthesis. Among extant species, flowers of the genus Calycanthus have the highest hydraulic conductance and vein densities of species measured to date, yet they can wilt by late morning under hot conditions. Here, we combine diurnal measurements of gas exchange and water potential, pressure-volume relations, functional responses of gas exchange, and characterization of embolism formation using high resolution X-ray computed microtomography to determine drought responses of Calycanthus flowers. Transpiration from flowers frequently exceeded transpiration from leaves, and flowers were unable to limit transpiration under conditions of high vapour pressure deficit. As a result, they rely heavily on hydraulic capacitance to prevent water potential declines. Despite having high water potentials at turgor loss, flowers were very resistant to embolism formation, with no embolism apparent until tepal water potentials had declined to -2 MPa. Although Calycanthus flowers remain connected to the stem xylem and have high hydraulic capacitance, their inability to curtail transpiration leads to turgor loss. These results suggest that extreme climate events may cause flower failure, potentially preventing successful reproduction.
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Affiliation(s)
- Adam B Roddy
- Department of Integrative Biology, University of California-Berkeley, Berkeley, CA, 94720, USA
- School of Forestry and Environmental Studies, Yale University, New Haven, CT, 06511, USA
| | - Kevin A Simonin
- Department of Biology, San Francisco State University, San Francisco, CA, 94132, USA
| | | | - Craig R Brodersen
- School of Forestry and Environmental Studies, Yale University, New Haven, CT, 06511, USA
| | - Todd E Dawson
- Department of Integrative Biology, University of California-Berkeley, Berkeley, CA, 94720, USA
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Abstract
OBJECTIVE The in vitro permeability characteristics of dentin have been studied extensively and used to evaluate the efficacy of various preventative and restorative procedures. The aim of this in vitro study was to precisely determine the dentin permeability of fluorotic premolar teeth using an electronic hydraulic conductance measurement system with photosensors and to compare the data with healthy premolars. METHODS In total, 40 fluorotic and healthy premolar teeth with complete root formation that were extracted for orthodontic purposes and had no caries, restoration, fractures, or cracks were selected for this study. Teeth were classified according to a modified form of the dental fluorosis index of Thylstrup and Fejerskov. The dentin discs were placed in an electronic hydraulic conductance measurement system equipped with photosensors, which was designed for measurements of dentin permeability. The amount of distilled water passed through each dentin disc (μL/min) under a constant pressure was determined. Dentin permeability data of the fluorotic and healthy teeth were recorded and analyzed statistically. RESULTS The present study showed that fluorosis influenced the volume of fluid that passed through the dentin and the dentin permeability was decreased, whereas dental fluorosis severity was increased in permanent teeth. CONCLUSION The number of teeth with fluorosis is increasing, depending on fluorine sources, so more appropriate treatments will need to be evaluated by standardizing the methods employed in related studies.
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Affiliation(s)
- K. Görkem Ulu Güzel
- Department of Pediatric Dentistry, Faculty of Dentistry, Adnan Menderes University, Aydın, Turkey
| | | | - Zuhal Kırzıoğlu
- Department of Pediatric Dentistry, Faculty of Dentistry, Süleyman Demirel University, Isparta, Turkey
| | - Suat Özkorucuklu
- Department of Physics, Faculty of Art Science, İstanbul University, İstanbul, Turkey
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Zadworny M, Comas LH, Eissenstat DM. Linking fine root morphology, hydraulic functioning and shade tolerance of trees. Ann Bot 2018; 122:239-250. [PMID: 29897405 PMCID: PMC6070046 DOI: 10.1093/aob/mcy054] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 03/28/2018] [Indexed: 05/17/2023]
Abstract
Background and Aims Understanding root traits and their trade-off with other plant processes is important for understanding plant functioning in natural ecosystems as well as agricultural systems. The aim of the present study was to determine the relationship between root morphology and the hydraulic characteristics of several orders of fine roots (<2 mm) for species differing in shade tolerance (low, moderate and high). Methods The morphological, anatomical and hydraulic traits across five distal root orders were measured in species with different levels of shade tolerance and life history strategies. The species studied were Acer negundo, Acer rubrum, Acer saccharum, Betula alleghaniensis, Betula lenta, Quercus alba, Quercus rubra, Pinus strobus and Pinus virginiana. Key Results Compared with shade-tolerant species, shade-intolerant species produced thinner absorptive roots with smaller xylem lumen diameters and underwent secondary development less frequently, suggesting that they had shorter life spans. Shade-tolerant species had greater root specific hydraulic conductance among these roots due to having larger diameter xylems, although these roots had a lower calculated critical tension for conduit collapse. In addition, shade-intolerant species exhibited greater variation in hydraulic conductance across different root growth rings in woody transport roots of the same root order as compared with shade-tolerant species. Conclusions Plant growth strategies were extended to include root hydraulic properties. It was found that shade intolerance in trees was associated with conservative root hydraulics but greater plasticity in number of xylem conduits and hydraulic conductance. Root traits of shade-intolerant species were consistent with the ability to proliferate roots quickly for rapid water uptake needed to support rapid shoot growth, while minimizing risk in uncertain environments.
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Affiliation(s)
- Marcin Zadworny
- Institute of Dendrology, Polish Academy of Sciences, Parkowa, Kórnik, Poland
| | - Louise H Comas
- USDA-ARS Water Management Research Unit, Fort Collins, CO, USA
| | - David M Eissenstat
- Intercollege Graduate Degree Program in Plant Biology, Penn State University, University Park, PA, USA
- Department of Ecosystem Science and Management, Penn State University, University Park, PA, USA
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Zhang H, Li W, Adams HD, Wang A, Wu J, Jin C, Guan D, Yuan F. Responses of Woody Plant Functional Traits to Nitrogen Addition: A Meta-Analysis of Leaf Economics, Gas Exchange, and Hydraulic Traits. Front Plant Sci 2018; 9:683. [PMID: 29875787 PMCID: PMC5974508 DOI: 10.3389/fpls.2018.00683] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 05/04/2018] [Indexed: 05/26/2023]
Abstract
Atmospheric nitrogen (N) deposition has been found to significantly affect plant growth and physiological performance in terrestrial ecosystems. Many individual studies have investigated how N addition influences plant functional traits, however these investigations have usually been limited to a single species, and thereby do not allow derivation of general patterns or underlying mechanisms. We synthesized data from 56 papers and conducted a meta-analysis to assess the general responses of 15 variables related to leaf economics, gas exchange, and hydraulic traits to N addition among 61 woody plant species, primarily from temperate and subtropical regions. Results showed that under N addition, leaf area index (+10.3%), foliar N content (+7.3%), intrinsic water-use efficiency (+3.1%) and net photosynthetic rate (+16.1%) significantly increased, while specific leaf area, stomatal conductance, and transpiration rate did not change. For plant hydraulics, N addition significantly increased vessel diameter (+7.0%), hydraulic conductance in stems/shoots (+6.7%), and water potential corresponding to 50% loss of hydraulic conductivity (P50, +21.5%; i.e., P50 became less negative), while water potential in leaves (-6.7%) decreased (became more negative). N addition had little effect on vessel density, hydraulic conductance in leaves and roots, or water potential in stems/shoots. N addition had greater effects on gymnosperms than angiosperms and ammonium nitrate fertilization had larger effects than fertilization with urea, and high levels of N addition affected more traits than low levels. Our results demonstrate that N addition has coupled effects on both carbon and water dynamics of woody plants. Increased leaf N, likely fixed in photosynthetic enzymes and pigments leads to higher photosynthesis and water use efficiency, which may increase leaf growth, as reflected in LAI results. These changes appear to have downstream effects on hydraulic function through increases in vessel diameter, which leads to higher hydraulic conductance, but lower water potential and increased vulnerability to embolism. Overall, our results suggest that N addition will shift plant function along a tradeoff between C and hydraulic economies by enhancing C uptake while simultaneously increasing the risk of hydraulic dysfunction.
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Affiliation(s)
- Hongxia Zhang
- Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Weibin Li
- State Key Laboratory of Grassland and Agro-Ecosystems, Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, China
| | - Henry D. Adams
- Department of Plant Biology, Ecology and Evolution, Oklahoma State University, Stillwater, OK, United States
| | - Anzhi Wang
- Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China
| | - Jiabing Wu
- Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China
| | - Changjie Jin
- Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China
| | - Dexin Guan
- Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China
| | - Fenghui Yuan
- Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China
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Zhu J, Dai Z, Vivin P, Gambetta GA, Henke M, Peccoux A, Ollat N, Delrot S. A 3-D functional-structural grapevine model that couples the dynamics of water transport with leaf gas exchange. Ann Bot 2018; 121:833-848. [PMID: 29293870 PMCID: PMC5906973 DOI: 10.1093/aob/mcx141] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 11/01/2017] [Indexed: 05/03/2023]
Abstract
Background and Aims Predicting both plant water status and leaf gas exchange under various environmental conditions is essential for anticipating the effects of climate change on plant growth and productivity. This study developed a functional-structural grapevine model which combines a mechanistic understanding of stomatal function and photosynthesis at the leaf level (i.e. extended Farqhuhar-von Caemmerer-Berry model) and the dynamics of water transport from soil to individual leaves (i.e. Tardieu-Davies model). Methods The model included novel features that account for the effects of xylem embolism (fPLC) on leaf hydraulic conductance and residual stomatal conductance (g0), variable root and leaf hydraulic conductance, and the microclimate of individual organs. The model was calibrated with detailed datasets of leaf photosynthesis, leaf water potential, xylem sap abscisic acid (ABA) concentration and hourly whole-plant transpiration observed within a soil drying period, and validated with independent datasets of whole-plant transpiration under both well-watered and water-stressed conditions. Key Results The model well captured the effects of radiation, temperature, CO2 and vapour pressure deficit on leaf photosynthesis, transpiration, stomatal conductance and leaf water potential, and correctly reproduced the diurnal pattern and decline of water flux within the soil drying period. In silico analyses revealed that decreases in g0 with increasing fPLC were essential to avoid unrealistic drops in leaf water potential under severe water stress. Additionally, by varying the hydraulic conductance along the pathway (e.g. root and leaves) and changing the sensitivity of stomatal conductance to ABA and leaf water potential, the model can produce different water use behaviours (i.e. iso- and anisohydric). Conclusions The robust performance of this model allows for modelling climate effects from individual plants to fields, and for modelling plants with complex, non-homogenous canopies. In addition, the model provides a basis for future modelling efforts aimed at describing the physiology and growth of individual organs in relation to water status.
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Affiliation(s)
- Junqi Zhu
- EGFV, Bordeaux Sciences Agro, INRA, Université de Bordeaux, Villenave d’Ornon, France
| | - Zhanwu Dai
- EGFV, Bordeaux Sciences Agro, INRA, Université de Bordeaux, Villenave d’Ornon, France
| | - Philippe Vivin
- EGFV, Bordeaux Sciences Agro, INRA, Université de Bordeaux, Villenave d’Ornon, France
| | - Gregory A Gambetta
- EGFV, Bordeaux Sciences Agro, INRA, Université de Bordeaux, Villenave d’Ornon, France
| | - Michael Henke
- Department of Ecoinformatics, Biometrics and Forest Growth, University of Göttingen, Göttingen, Germany
| | - Anthony Peccoux
- EGFV, Bordeaux Sciences Agro, INRA, Université de Bordeaux, Villenave d’Ornon, France
| | - Nathalie Ollat
- EGFV, Bordeaux Sciences Agro, INRA, Université de Bordeaux, Villenave d’Ornon, France
| | - Serge Delrot
- EGFV, Bordeaux Sciences Agro, INRA, Université de Bordeaux, Villenave d’Ornon, France
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Yin XH, Hao GY. [Divergence between ring- and diffuse-porous wood types in broadleaf trees of Changbai Mountains results in substantial differences in hydraulic traits.]. Ying Yong Sheng Tai Xue Bao 2018; 29:352-360. [PMID: 29692047 DOI: 10.13287/j.1001-9332.201802.035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Hydraulic characteristics of trees are strongly influenced by their xylem structures. The divergence in wood type between ring-porous and diffuse-porous species is expected to lead to significantly different hydraulic architecture between these two functional groups. However, there is a lack of comprehensive comparative studies in hydraulic traits between the two groups, in that no study has compared the whole-shoot level hydraulic conductance and detailed pit-level xylem anatomy has not been reported yet. In the present study, detailed hydraulic related traits were stu-died in three ring-porous and four diffuse-porous tree species commonly found in the broadleaf tree species of the Changbai Mountains, including whole-shoot hydraulic conductance (Kshoot), resis-tance to drought-induced embolism (P50), and detailed tissue- and pit-level anatomical characteristics. Our results showed that: 1) consistent with the differences in stem hydraulic conductivity, ring-porous species showed significantly higher Kshoot but significantly lower resistance to drought-induced embolism, i.e., higher P50, indicating a trade-off between hydraulic efficiency and safety in those two functional groups; 2) consistent with their significant divergence in hydraulic functions, the two functional groups showed significant differences in a suite of xylem anatomical characteristics at both the tissue and pit levels, such as maximum vessel length, vessel diameter, pit aperture area and aperture fraction; 3) significant correlations were identified between xylem structural characteristics and between structure and functions across both functional groups, indicating that differences in hydraulic functions were underlain by divergences in a suite structural traits. The competing structural requirements between different hydraulic traits, such as between shoot hydraulic conductance and resistance to drought-induced embolism, reflected the biophysical constraints of xylem design that could not fulfill multiple requirements of xylem functioning at the same time.
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Affiliation(s)
- Xiao Han Yin
- Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Science, Shenyang 110016, Liaoning, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Guang You Hao
- Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Science, Shenyang 110016, Liaoning, China
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Dewar R, Mauranen A, Mäkelä A, Hölttä T, Medlyn B, Vesala T. New insights into the covariation of stomatal, mesophyll and hydraulic conductances from optimization models incorporating nonstomatal limitations to photosynthesis. New Phytol 2018; 217:571-585. [PMID: 29086921 DOI: 10.1111/nph.14848] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 09/10/2017] [Indexed: 05/08/2023]
Abstract
Optimization models of stomatal conductance (gs ) attempt to explain observed stomatal behaviour in terms of cost--benefit tradeoffs. While the benefit of stomatal opening through increased CO2 uptake is clear, currently the nature of the associated cost(s) remains unclear. We explored the hypothesis that gs maximizes leaf photosynthesis, where the cost of stomatal opening arises from nonstomatal reductions in photosynthesis induced by leaf water stress. We analytically solved two cases, CAP and MES, in which reduced leaf water potential leads to reductions in carboxylation capacity (CAP) and mesophyll conductance (gm ) (MES). Both CAP and MES predict the same one-parameter relationship between the intercellular : atmospheric CO2 concentration ratio (ci /ca ) and vapour pressure deficit (VPD, D), viz. ci /ca ≈ ξ/(ξ + √D), as that obtained from previous optimization models, with the novel feature that the parameter ξ is determined unambiguously as a function of a small number of photosynthetic and hydraulic variables. These include soil-to-leaf hydraulic conductance, implying a stomatal closure response to drought. MES also predicts that gs /gm is closely related to ci /ca and is similarly conservative. These results are consistent with observations, give rise to new testable predictions, and offer new insights into the covariation of stomatal, mesophyll and hydraulic conductances.
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Affiliation(s)
- Roderick Dewar
- Plant Sciences Division, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Aleksanteri Mauranen
- Department of Physics, University of Helsinki, PO Box 68, Helsinki, FI-00014, Finland
| | - Annikki Mäkelä
- Department of Forest Sciences, University of Helsinki, PO Box 27, Helsinki, FI-00014, Finland
| | - Teemu Hölttä
- Department of Forest Sciences, University of Helsinki, PO Box 27, Helsinki, FI-00014, Finland
| | - Belinda Medlyn
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
| | - Timo Vesala
- Department of Physics, University of Helsinki, PO Box 68, Helsinki, FI-00014, Finland
- Department of Forest Sciences, University of Helsinki, PO Box 27, Helsinki, FI-00014, Finland
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