1
|
Gibson VL, Richards Donà A, Smith CM. Measuring tissue water potential in marine macroalgae via an updated Chardakov method. AOB PLANTS 2023; 15:plad055. [PMID: 37899983 PMCID: PMC10601392 DOI: 10.1093/aobpla/plad055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Accepted: 08/10/2023] [Indexed: 10/31/2023]
Abstract
Regulation of tissue water potential is a key mechanism in macroalgal osmotic responses to changing external osmotic conditions, which are common in tidally influenced estuarine and intertidal systems. Nevertheless, significant knowledge gaps exist in our understanding of osmotic responses in macroalgae because few methods measure osmotic potential within macroalgal tissues. Leaf psychrometers have furthered understanding of osmotic potentials in terrestrial plant water relations, yet these have not been developed to measure the range of highly negative potential values found in marine macroalgae. To address these gaps, we present an effective, updated version of the Chardakov method to measure tissue water potential in macroalgae. Here, we present a case study examining macroalgal response in tissue water potential by two morphologically and evolutionarily distinct species, Ulva lactuca (Chlorophyta) and Hypnea musciformis (Rhodophyta) to four paired salinity and nutrient treatments at two temperatures. These treatments simulate a gradient from full coastal ocean conditions to brackish submarine groundwater discharge, an ecosystem type found on basaltic shorelines. Both algae demonstrated plasticity in osmotic response to submarine groundwater discharge with significant positive correlations between tissue water potential and proportion of submarine groundwater discharge in the treatment. These results are the first to describe macroalgal response in tissue water potential, a first step to understanding algal physiological ecology in such complex coastal environments. This revised Chardakov method is a valuable tool to better understand species-specific osmotic responses to ecologically relevant conditions, and can augment the study of other tidal systems and ontogenetic stages.
Collapse
Affiliation(s)
- V L Gibson
- School of Life Sciences, University of Hawai‘i at Mānoa, 310 Maile Way, St John 101, Honolulu, HI 96822, USA
- Water Resources Research Center, University of Hawai‘i at Mānoa, 2540 Dole Street, Holmes Hall 293, Honolulu, HI 96822, USA
- Hawaiʻi Institute of Marine Biology, University of Hawaiʻi at Mānoa, 46-007 Lilipuna Road, Kāneʻohe, HI 96744, USA
| | - A Richards Donà
- School of Life Sciences, University of Hawai‘i at Mānoa, 310 Maile Way, St John 101, Honolulu, HI 96822, USA
- Water Resources Research Center, University of Hawai‘i at Mānoa, 2540 Dole Street, Holmes Hall 293, Honolulu, HI 96822, USA
| | - C M Smith
- School of Life Sciences, University of Hawai‘i at Mānoa, 310 Maile Way, St John 101, Honolulu, HI 96822, USA
| |
Collapse
|
2
|
Jiang P, Yan J, Liu R, Zhang X, Fan S. Patterns of deep fine root and water utilization amongst trees, shrubs and herbs in subtropical pine plantations with seasonal droughts. FRONTIERS IN PLANT SCIENCE 2023; 14:1275464. [PMID: 37799557 PMCID: PMC10548128 DOI: 10.3389/fpls.2023.1275464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 09/05/2023] [Indexed: 10/07/2023]
Abstract
Introduction Seasonal droughts will become more severe and frequent under the context of global climate change, this would result in significant variations in the root distribution and water utilization patterns of plants. However, research on the determining factors of deep fine root and water utilization is limited. Methods We measured the fine root biomass and water utilization of trees, shrubs and herbs, and soil properties, light transmission, and community structure parameters in subtropical pine plantations with seasonal droughts. Results and Discussion We found that the proportion of deep fine roots (below 1 m depth) is only 0.2-5.1%, but that of deep soil water utilization can reach 20.9-38.6% during the dry season. Trees improve deep soil water capture capacity by enhancing their dominance in occupying deep soil volume, and enhance their deep resource foraging by increasing their branching capacity of absorptive roots. Shrubs and herbs showed different strategies for deep water competition: shrubs tend to exhibit a "conservative" strategy and tend to increase individual competitiveness, while herbs exhibited an "opportunistic" strategy and tend to increase variety and quantity to adapt to competitions. Conclusion Our results improve our understanding of different deep fine root distribution and water use strategies between overstory trees and understory vegetations, and emphasize the importance of deep fine root in drought resistance as well as the roles of deep soil water utilization in shaping community assembly.
Collapse
Affiliation(s)
- Peipei Jiang
- Key Lab of Plant Stress Research, College of Life Sciences, Shandong Normal University, Ji’nan, Shandong, China
| | - Jinliang Yan
- Yangji Forest Farm (Yangtianshan Provincial Nature Reserve Protection Center) of Qingzhou, Weifang, Shandong, China
| | - Rongxin Liu
- Key Lab of Plant Stress Research, College of Life Sciences, Shandong Normal University, Ji’nan, Shandong, China
| | - Xuejie Zhang
- Key Lab of Plant Stress Research, College of Life Sciences, Shandong Normal University, Ji’nan, Shandong, China
| | - Shoujin Fan
- Key Lab of Plant Stress Research, College of Life Sciences, Shandong Normal University, Ji’nan, Shandong, China
| |
Collapse
|
3
|
Aritsara ANA, Ni MY, Wang YQ, Yan CL, Zeng WH, Song HQ, Cao KF, Zhu SD. Tree growth is correlated with hydraulic efficiency and safety across 22 tree species in a subtropical karst forest. TREE PHYSIOLOGY 2023; 43:1307-1318. [PMID: 37067918 DOI: 10.1093/treephys/tpad050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 03/16/2023] [Accepted: 04/12/2023] [Indexed: 06/19/2023]
Abstract
Karst forests are habitats in which access to soil water can be challenging for plants. Therefore, safe and efficient xylem water transport and large internal water storage may benefit tree growth. In this study, we selected 22 tree species from a primary subtropical karst forest in southern China and measured their xylem anatomical traits, saturated water content (SWC), hydraulic conductivity (Ks) and embolism resistance (P50). Additionally, we monitored growth of diameter at breast height (DBH) in 440 individual trees of various sizes over three consecutive years. Our objective was to analyze the relationships between xylem structure, hydraulic efficiency, safety, water storage and growth of karst tree species. The results showed significant differences in structure but not in hydraulic traits between deciduous and evergreen species. Larger vessel diameter, paratracheal parenchyma and higher SWC were correlated with higher Ks. Embolism resistance was not correlated with the studied anatomical traits, and no tradeoff with Ks was observed. In small trees (5-15 cm DBH), diameter growth rate (DGR) was independent of hydraulic traits. In large trees (>15 cm DBH), higher Ks and more negative P50 accounted for higher DGR. From lower to greater embolism resistance, the size-growth relationship shifted from growth deceleration to acceleration with increasing tree size in eight of the 22 species. Our study highlights the vital contributions of xylem hydraulic efficiency and safety to growth rate and dynamics in karst tree species; therefore, we strongly recommend their integration into trait-based forest dynamic models.
Collapse
Affiliation(s)
- Amy N A Aritsara
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, No. 100 Daxuedonglu Road, Nanning 530004, Guangxi, China
- College of Life Sciences and Technology, Guangxi University, No. 100 Daxuedonglu Road, Nanning 530004, Guangxi, China
| | - Ming-Yuan Ni
- School of Basic Medical Sciences, Youjiang Medical University for Nationalities, No. 98 Chengxiang Road, Baise 533000, Guangxi, China
| | - Yong-Qiang Wang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, No. 100 Daxuedonglu Road, Nanning 530004, Guangxi, China
| | - Chao-Long Yan
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, No. 100 Daxuedonglu Road, Nanning 530004, Guangxi, China
| | - Wen-Hao Zeng
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, No. 100 Daxuedonglu Road, Nanning 530004, Guangxi, China
| | - Hui-Qing Song
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, No. 100 Daxuedonglu Road, Nanning 530004, Guangxi, China
| | - Kun-Fang Cao
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, No. 100 Daxuedonglu Road, Nanning 530004, Guangxi, China
| | - Shi-Dan Zhu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, No. 100 Daxuedonglu Road, Nanning 530004, Guangxi, China
| |
Collapse
|
4
|
Reyes-García C, Orellana R, Dzib Ek S, Peniche Aké S, Tamayo-Chim M, Echevarría-Machado I, Carrillo L, Espadas-Manrique C. Weak crassulacean acid metabolism and other xerophytic adaptive traits in the genus Beaucarnea Lem. (Asparagaceae). PHYSIOLOGIA PLANTARUM 2022; 174:e13816. [PMID: 36321977 DOI: 10.1111/ppl.13816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 10/05/2022] [Accepted: 10/28/2022] [Indexed: 06/16/2023]
Abstract
The genus Beaucarnea (Asparagaceae) has economic value as an ornamental plant but also has ecological importance. Nonetheless, habitat, physiological traits and growth parameters of this genus remain largely unknown. We characterized the environmental ranges of Beaucarnea inermis, B. gracilis and B. pliabilis; and screened for the presence of physiological adaptations to drought (biomass allocation, presence of crassulacean acid metabolism [CAM] and its effect on plant water use). We performed experiments in 3- and 5-year-old nursery-grown plants of the three species, measured dry mass accumulation in leaves/stems/roots and screened for CAM using gas exchange, titratable acidity and δ13 C. We performed a second experiment on the water and light use responses of B. pliabilis under drought treatment. We found that B. gracilis was limited to xerophytic scrubs (precipitation >400 mm yr-1 ), while B. pliabilis and B. inermis (precipitation >500 and 700 mm year-1 , respectively) inhabited dry forests. Beaucarnea gracilis had the lowest dry mass and allocation to leaves, while B. inermis showed the opposite pattern. Only B. pliabilis exhibited small but significant acid fluctuations, characterized as weak CAM, along with high proline content. Acid concentration contributed in 2.7% of the daily carbon during the wet season but represented most of the carbon in the dry season, under closed stomata and had an important contribution to osmolality. Thus, CAM is described for the first time in the genus Beaucarnea, but was only present in one of three species, warranting exploration of this metabolism in the remaining species of this genus.
Collapse
Affiliation(s)
- Casandra Reyes-García
- Unidad de Recursos Naturales, Centro de Investigación Científica de Yucatán, Mérida, Mexico
| | - Roger Orellana
- Unidad de Recursos Naturales, Centro de Investigación Científica de Yucatán, Mérida, Mexico
| | - Susana Dzib Ek
- Unidad de Recursos Naturales, Centro de Investigación Científica de Yucatán, Mérida, Mexico
| | - Stephany Peniche Aké
- Unidad de Recursos Naturales, Centro de Investigación Científica de Yucatán, Mérida, Mexico
| | - Manuela Tamayo-Chim
- Unidad de Recursos Naturales, Centro de Investigación Científica de Yucatán, Mérida, Mexico
| | | | - Lilia Carrillo
- Unidad de Recursos Naturales, Centro de Investigación Científica de Yucatán, Mérida, Mexico
| | | |
Collapse
|
5
|
Gauthey A, Backes D, Balland J, Alam I, Maher DT, Cernusak LA, Duke NC, Medlyn BE, Tissue DT, Choat B. The Role of Hydraulic Failure in a Massive Mangrove Die-Off Event. FRONTIERS IN PLANT SCIENCE 2022; 13:822136. [PMID: 35574083 PMCID: PMC9094047 DOI: 10.3389/fpls.2022.822136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 03/25/2022] [Indexed: 06/15/2023]
Abstract
Between late 2015 and early 2016, more than 7,000 ha of mangrove forest died along the coastline of the Gulf of Carpentaria, in northern Australia. This massive die-off was preceded by a strong 2015/2016 El Niño event, resulting in lower precipitation, a drop in sea level and higher than average temperatures in northern Australia. In this study, we investigated the role of hydraulic failure in the mortality and recovery of the dominant species, Avicennia marina, 2 years after the mortality event. We measured predawn water potential (Ψpd) and percent loss of stem hydraulic conductivity (PLC) in surviving individuals across a gradient of impact. We also assessed the vulnerability to drought-induced embolism (Ψ50) for the species. Areas with severe canopy dieback had higher native PLC (39%) than minimally impacted areas (6%), suggesting that hydraulic recovery was ongoing. The high resistance of A. marina to water-stress-induced embolism (Ψ50 = -9.6 MPa), indicates that severe water stress (Ψpd < -10 MPa) would have been required to cause mortality in this species. Our data indicate that the natural gradient of water-stress enhanced the impact of El Niño, leading to hydraulic failure and mortality in A. marina growing on severely impacted (SI) zones. It is likely that lowered sea levels and less frequent inundation by seawater, combined with lower inputs of fresh water, high evaporative demand and high temperatures, led to the development of hyper-salinity and extreme water stress during the 2015/16 summer.
Collapse
Affiliation(s)
- Alice Gauthey
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
- Plant Ecology Research Laboratory PERL, Ecole Polytechnique Fédérale de Lausanne EPFL, Lausanne, Switzerland
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
| | - Diana Backes
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
| | - Jeff Balland
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
| | - Iftakharul Alam
- College of Science and Engineering, James Cook University, Cairns, QLD, Australia
| | - Damien T. Maher
- Faculty of Science and Engineering, Southern Cross University, Lismore, NSW, Australia
| | - Lucas A. Cernusak
- College of Science and Engineering, James Cook University, Cairns, QLD, Australia
| | - Norman C. Duke
- TropWATER Centre, James Cook University, Townsville, QLD, Australia
| | - Belinda E. Medlyn
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
| | - David T. Tissue
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
| | - Brendan Choat
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
| |
Collapse
|
6
|
Luna‐Nieves AL, González EJ, Cortés‐Flores J, Ibarra‐Manríquez G, Maldonado‐Romo A, Meave JA. Interplay of environmental cues and wood density in the vegetative and reproductive phenology of seasonally dry tropical forest trees. Biotropica 2022. [DOI: 10.1111/btp.13072] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Adriana L. Luna‐Nieves
- Departamento de Ecología y Recursos Naturales Facultad de Ciencias Universidad Nacional Autónoma de México Ciudad de México Mexico
| | - Edgar J. González
- Departamento de Ecología y Recursos Naturales Facultad de Ciencias Universidad Nacional Autónoma de México Ciudad de México Mexico
| | - Jorge Cortés‐Flores
- Jardín Botánico Instituto de Biología Universidad Nacional Autónoma de México Ciudad de México Mexico
| | - Guillermo Ibarra‐Manríquez
- Instituto de Investigaciones en Ecosistemas y Sustentabilidad Universidad Nacional Autónoma de México Morelia Mich. Mexico
| | - Axel Maldonado‐Romo
- Departamento de Ecología y Recursos Naturales Facultad de Ciencias Universidad Nacional Autónoma de México Ciudad de México Mexico
| | - Jorge A. Meave
- Departamento de Ecología y Recursos Naturales Facultad de Ciencias Universidad Nacional Autónoma de México Ciudad de México Mexico
| |
Collapse
|
7
|
Baer AB, Fickle JC, Medina J, Robles C, Pratt RB, Jacobsen AL. Xylem biomechanics, water storage, and density within roots and shoots of an angiosperm tree species. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:7984-7997. [PMID: 34410349 DOI: 10.1093/jxb/erab384] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 08/17/2021] [Indexed: 06/13/2023]
Abstract
Xylem is a complex tissue that forms the bulk of tree bodies and has several functions, including to conduct water, store water and nutrients, and biomechanically support the plant body. We examined how xylem functional traits varied at different positions within 9-year-old Populus balsamifera subsp. trichocarpa. Whole trees were excavated, and xylem samples were collected at 1-m increments along the main root-to-shoot axis of six trees, from root tip to shoot tip. We examined biomechanical and water-storage traits of the xylem, including using a non-invasive imaging technique to examine water content within long, intact branches (high-resolution computed tomography; microCT). Xylem density, strength, and stiffness were greater in shoots than roots. Along the main root-to-shoot axis, xylem strength and stiffness were greatest at shoot tips, and the tissue became linearly weaker and less stiff down the plant and through the root. Roots had greater water storage with lower biomechanical support, and shoots had biomechanically stronger and stiffer xylem with lower water storage. These findings support trade-offs among xylem functions between roots and shoots. Understanding how xylem functions differ throughout tree bodies is important in understanding whole-tree functioning and how terrestrial plants endure numerous environmental challenges over decades of growth.
Collapse
Affiliation(s)
- Alex B Baer
- Department of Biology, California State University, Bakersfield, CA, 93311, USA
| | - Jaycie C Fickle
- Department of Biology, California State University, Bakersfield, CA, 93311, USA
| | - Jackeline Medina
- Department of Biology, California State University, Bakersfield, CA, 93311, USA
| | - Catherine Robles
- Department of Biology, California State University, Bakersfield, CA, 93311, USA
| | - R Brandon Pratt
- Department of Biology, California State University, Bakersfield, CA, 93311, USA
| | - Anna L Jacobsen
- Department of Biology, California State University, Bakersfield, CA, 93311, USA
| |
Collapse
|
8
|
Słupianek A, Dolzblasz A, Sokołowska K. Xylem Parenchyma-Role and Relevance in Wood Functioning in Trees. PLANTS (BASEL, SWITZERLAND) 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] [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.
Collapse
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.)
| | | | | |
Collapse
|
9
|
Rodríguez-Calcerrada J, Rodrigues AM, António C, Perdiguero P, Pita P, Collada C, Li M, Gil L. Stem metabolism under drought stress - a paradox of increasing respiratory substrates and decreasing respiratory rates. PHYSIOLOGIA PLANTARUM 2021; 172:391-404. [PMID: 32671841 DOI: 10.1111/ppl.13145] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 05/25/2020] [Accepted: 05/28/2020] [Indexed: 06/11/2023]
Abstract
Metabolic changes underpinning drought-induced variations in stem respiration (Rs ) are unknown. We measured Rs rates and metabolite and gene expression profiles in Ulmus minor Mill. and Quercus ilex L. seedlings subjected to increasing levels of drought stress to better understand how carbon, nitrogen and energy metabolism interact during drought. In both species, only plants showing extreme stress symptoms - i.e. negligible rates of leaf stomatal conductance and photosynthesis, and high stem dehydration (30-50% of maximum water storage) and contraction (50-150 μm week-1 ) - exhibited lower Rs rates than well-watered plants. Abundance of low-molecular weight sugars (e.g. glucose and fructose) and sugar alcohols (e.g. mannitol) increased with drought, at more moderate stress and to a higher extent in Q. ilex than U. minor. Abundance of amino acids increased at more severe stress, more abruptly, and to a higher extent in U. minor, coinciding with leaf senescence, which did not occur in Q. ilex. Organic acids changed less in response to drought: threonate and glycerate increased, and citrate decreased although slightly in both species. Transcripts of genes coding for enzymes of the Krebs cycle decreased in Q. ilex and increased in U. minor in conditions of extreme drought stress. The maintenance of Rs under severe growth and photosynthetic restrictions reveals the importance of stem mitochondrial activity in drought acclimation. The eventual decline in Rs diverts carbon substrates from entering the Krebs cycle that may help to cope with osmotic and oxidative stress during severe drought and to recover hydraulic functionality afterwards.
Collapse
Affiliation(s)
- Jesús Rodríguez-Calcerrada
- Grupo de Investigación Sistemas Naturales e Historia Forestal, Universidad Politécnica de Madrid, Madrid, 28040, Spain
| | - Ana M Rodrigues
- Plant Metabolomics Laboratory, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), Oeiras, 2780-157, Portugal
| | - Carla António
- Plant Metabolomics Laboratory, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), Oeiras, 2780-157, Portugal
| | - Pedro Perdiguero
- Animal Health Research Center, National Institute for Agriculture and Food Research and Technology (CISA-INIA), Valdeolmos, Madrid, 28130, Spain
| | - Pilar Pita
- Grupo de Investigación Sistemas Naturales e Historia Forestal, Universidad Politécnica de Madrid, Madrid, 28040, Spain
| | - Carmen Collada
- Grupo de Investigación Sistemas Naturales e Historia Forestal, Universidad Politécnica de Madrid, Madrid, 28040, Spain
| | - Meng Li
- Grupo de Investigación Sistemas Naturales e Historia Forestal, Universidad Politécnica de Madrid, Madrid, 28040, Spain
| | - Luis Gil
- Grupo de Investigación Sistemas Naturales e Historia Forestal, Universidad Politécnica de Madrid, Madrid, 28040, Spain
| |
Collapse
|
10
|
Ziemińska K, Rosa E, Gleason SM, Holbrook NM. Wood day capacitance is related to water content, wood density, and anatomy across 30 temperate tree species. PLANT, CELL & ENVIRONMENT 2020; 43:3048-3067. [PMID: 32935340 DOI: 10.1111/pce.13891] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 09/05/2020] [Accepted: 09/07/2020] [Indexed: 06/11/2023]
Abstract
Water released from wood during transpiration (capacitance) can meaningfully affect daily water use and drought response. To provide context for better understanding of capacitance mechanisms, we investigated links between capacitance and wood anatomy. On twigs of 30 temperate angiosperm tree species, we measured day capacitance (between predawn and midday), water content, wood density, and anatomical traits, that is, vessel dimensions, tissue fractions, and vessel-tissue contact fractions (fraction of vessel circumference in contact with other tissues). Across all species, wood density (WD) and predawn lumen volumetric water content (VWCL-pd ) together were the strongest predictors of day capacitance (r2adj = .44). Vessel-tissue contact fractions explained an additional ~10% of the variation in day capacitance. Regression models were not improved by including tissue lumen fractions. Among diffuse-porous species, VWCL-pd and vessel-ray contact fraction together were the best predictors of day capacitance, whereas among semi/ring-porous species, VWCL-pd , WD and vessel-fibre contact fraction were the best predictors. At predawn, wood was less than fully saturated for all species (lumen relative water content = 0.52 ± 0.17). Our findings imply that day capacitance depends on the amount of stored water, tissue connectivity and the bulk wood properties arising from WD (e.g., elasticity), rather than the fraction of any particular tissue.
Collapse
Affiliation(s)
- Kasia Ziemińska
- Arnold Arboretum of Harvard University, Boston, Massachusetts, USA
- Department of Plant Ecology and Evolution, Uppsala University, Uppsala, Sweden
| | - Emily Rosa
- Department of Biology, Sonoma State University, Rohnert Park, California, USA
| | - Sean M Gleason
- United States Department of Agriculture - Agricultural Research Service, Water Management and Systems Research Unit, Fort Collins, Colorado, USA
| | - N Michele Holbrook
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA
| |
Collapse
|
11
|
Di Lucchio LM, Fensholt R, Markussen B, Ræbild A. Leaf phenology of thirteen African origins of baobab ( Adansonia digitata (L.)) as influenced by daylength and water availability. Ecol Evol 2018; 8:11261-11272. [PMID: 30519442 PMCID: PMC6262930 DOI: 10.1002/ece3.4600] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 09/04/2018] [Accepted: 09/14/2018] [Indexed: 11/08/2022] Open
Abstract
Water availability is often described as one of the main drivers of phenology of tropical dry forests but experimental studies to identify the cues triggering phenological changes are few. In a greenhouse trial, we exposed seedlings of thirteen origins, seven from West and six from East Africa, respectively, of Adansonia digitata L.(baobab) to a well-watered control treatment and a water withholding treatment in combination with exposure to three different daylengths (11.5, 12.0, and 12.5 hr). Responses were measured in terms of meristematic activity, number of leaves, and height growth followed over 6.5 months. Multi-level mixed-effects statistical models were used to analyze how environmental and inter-population variables affected phenological behavior. Flushing was influenced by the daylength with the lowest degree of meristematic activity observed in the short daylength treatment. Daylength also influenced the number of leaves through an interaction with the water regime. The water regime influenced all variables through interactions with the origins. Seedlings subjected to water stress had higher meristematic activity, but initially lower numbers of leaves than continuously watered plants. Height growth in continuously watered plants was fastest or at par with water-stressed plants, depending on the origin. Origins from West Africa tended to have higher meristematic activity and their phenology was found to be less influenced by water withholding than East African origins. There were no signs of significant differences between origins in their response to photoperiod. In conclusion, baobab seedlings show opportunistic behavior, setting leaves when water is available, but larger activity is found when days are long. We discuss the results in terms of triggering factors for baobab phenology and adaptation to specific environmental conditions at the site of origins.
Collapse
Affiliation(s)
| | - Rasmus Fensholt
- Department of Geosciences and Natural Resource ManagementUniversity of CopenhagenCopenhagenDenmark
| | - Bo Markussen
- Laboratory for Applied Statistics, Department of Mathematical SciencesUniversity of CopenhagenCopenhagenDenmark
| | - Anders Ræbild
- Department of Geosciences and Natural Resource ManagementUniversity of CopenhagenCopenhagenDenmark
| |
Collapse
|
12
|
Kaplick J, Clearwater M, Macinnis-Ng C. Stem water storage of New Zealand kauri (Agathis australis). ACTA ACUST UNITED AC 2018. [DOI: 10.17660/actahortic.2018.1222.9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
13
|
Butz P, Hölscher D, Cueva E, Graefe S. Tree Water Use Patterns as Influenced by Phenology in a Dry Forest of Southern Ecuador. FRONTIERS IN PLANT SCIENCE 2018; 9:945. [PMID: 30034407 PMCID: PMC6043675 DOI: 10.3389/fpls.2018.00945] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 06/12/2018] [Indexed: 06/08/2023]
Abstract
Tropical dry forests are composed of tree species with different drought coping strategies and encompass heterogeneous site conditions. Actual water use will be controlled by soil moisture availability. In a premontane dry forest of southern Ecuador, tree water use patterns of four tree species of different phenologies were studied along an elevational gradient, in which soil moisture availability increases with altitude. Main interest was the influence of variation in soil moisture, vapor pressure deficit, species (representing phenology), elevation, and tree diameter on water use. Special emphasis was put on the stem succulent, deciduous Ceiba trichistandra, as high water use rates and drought coping involving stem succulence was to be expected. Tree water use rates increased linearly with diameter across species at high soil water content. However, when soil moisture declined, sap flux densities of the species responded differently. The stem succulent, deciduous Ceiba and other deciduous tree species reduced sap flux sensitively, whereas sap flux densities of the evergreen (broad leaved) Capparis scabrida were increasing. This was also reflected in diurnal hysteresis loops of sap flux vs. vapor pressure deficit (VPD) of the air. Under dry soil conditions, Ceiba and other deciduous tree species had much smaller areas in the hysteresis loop, whereas the area of Capparis was largely enhanced compared to wet conditions. The evergreen Capparis potentially had access to deeper soil water resources as water use patterns suggest that top soil drought was tolerated. The deciduous species followed a drought avoidance strategy by being leafless in the dry season. The stem succulent deciduous Ceiba flushed leaves at the end of the dry season before the rainy season began and also re-flushed early in the dry season after a rain event; however, water use rates at this occasion remained low. Ceiba was also ready for fast and strong response in water use when conditions were most favorable during the wet season. The study thus indicates a strong influence of species' drought coping strategy on water use patterns in tropical dry forests.
Collapse
Affiliation(s)
- Philipp Butz
- Tropical Silviculture and Forest Ecology, University of Göttingen, Göttingen, Germany
| | - Dirk Hölscher
- Tropical Silviculture and Forest Ecology, University of Göttingen, Göttingen, Germany
| | | | - Sophie Graefe
- Tropical Silviculture and Forest Ecology, University of Göttingen, Göttingen, Germany
| |
Collapse
|
14
|
Hearn DJ, O’Brien P, Poulsen SM. Comparative transcriptomics reveals shared gene expression changes during independent evolutionary origins of stem and hypocotyl/root tubers in Brassica (Brassicaceae). PLoS One 2018; 13:e0197166. [PMID: 29856865 PMCID: PMC5983522 DOI: 10.1371/journal.pone.0197166] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 04/27/2018] [Indexed: 11/18/2022] Open
Abstract
Plant succulence provides a classic example of evolutionary convergence in over 40 plant families. If evolutionary parallelism is in fact responsible for separate evolutionary origins of expanded storage tissues in stems, hypocotyls, and roots, we expect similar gene expression profiles in stem and hypocotyl / root tubers. We analyzed RNA-Seq transcript abundance patterns in stem and hypocotyl / root tubers of the Brassica crops kohlrabi (B. oleracea) and turnip (B. rapa) and compared their transcript expression profiles to those in the conspecific thin-stemmed and thin-rooted crops flowering kale and pak choi, respectively. Across these four cultivars, 38,192 expressed gene loci were identified. Of the 3,709 differentially-expressed genes (DEGs) in the turnip: pak choi comparison and the 6,521 DEGs in the kohlrabi: kale comparison, turnips and kohlrabies share a statistically disproportionate overlap of 841 DEG homologs in their tubers (p value < 1e-10). This overlapping set is statistically enriched in biochemical functions that are also associated with tuber induction in potatoes and sweet potatoes: sucrose metabolism, lipoxygenases, auxin metabolism, and meristem development. These shared expression profiles in tuberous stems and root / hypocotyls in Brassica suggest parallel employment of shared molecular genetic pathways during the evolution of tubers in stems, hypocotyls and roots of Brassica crops and more widely in other tuberous plants as well.
Collapse
Affiliation(s)
- David J. Hearn
- Department of Biological Sciences, Towson University, Towson, Maryland, United States of America
| | - Patrick O’Brien
- Department of Biological Sciences, Towson University, Towson, Maryland, United States of America
| | - Sylvie M. Poulsen
- Department of Biological Sciences, Towson University, Towson, Maryland, United States of America
| |
Collapse
|
15
|
Matheny AM, Garrity SR, Bohrer G. The Calibration and Use of Capacitance Sensors to Monitor Stem Water Content in Trees. J Vis Exp 2017:57062. [PMID: 29364228 PMCID: PMC5908399 DOI: 10.3791/57062] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Water transport and storage through the soil-plant-atmosphere continuum is critical to the terrestrial water cycle, and has become a major research focus area. Biomass capacitance plays an integral role in the avoidance of hydraulic impairment to transpiration. However, high temporal resolution measurements of dynamic changes in the hydraulic capacitance of large trees are rare. Here, we present procedures for the calibration and use of capacitance sensors, typically used to monitor soil water content, to measure the volumetric water content in trees in the field. Frequency domain reflectometry-style observations are sensitive to the density of the media being studied. Therefore, it is necessary to perform species-specific calibrations to convert from the sensor-reported values of dielectric permittivity to volumetric water content. Calibration is performed on a harvested branch or stem cut into segments that are dried or re-hydrated to produce a full range of water contents used to generate a best-fit regression with sensor observations. Sensors are inserted into calibration segments or installed in trees after pre-drilling holes to a tolerance fit using a fabricated template to ensure proper drill alignment. Special care is taken to ensure that sensor tines make good contact with the surrounding media, while allowing them to be inserted without excessive force. Volumetric water content dynamics observed via the presented methodology align with sap flow measurements recorded using thermal dissipation techniques and environmental forcing data. Biomass water content data can be used to observe the onset of water stress, drought response and recovery, and has the potential to be applied to the calibration and evaluation of new plant-level hydrodynamics models, as well as to the partitioning of remotely sensed moisture products into above- and belowground components.
Collapse
Affiliation(s)
- Ashley M Matheny
- Department of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin;
| | | | - Gil Bohrer
- Department of Civil, Environmental and Geodetic Engineering, Ohio State University
| |
Collapse
|
16
|
Zlinszky A, Molnár B, Barfod AS. Not All Trees Sleep the Same-High Temporal Resolution Terrestrial Laser Scanning Shows Differences in Nocturnal Plant Movement. FRONTIERS IN PLANT SCIENCE 2017; 8:1814. [PMID: 29104583 PMCID: PMC5654925 DOI: 10.3389/fpls.2017.01814] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 10/05/2017] [Indexed: 06/01/2023]
Abstract
Circadian leaf movements are widely known in plants, but nocturnal movement of tree branches were only recently discovered by using terrestrial laser scanning (TLS), a high resolution three-dimensional surveying technique. TLS uses a pulsed laser emitted in a regular scan pattern for rapid measurement of distances to the targets, thus producing three dimensional point cloud models of sub-centimeter resolution and accuracy in a few minutes. Here, we aim to gain an overview of the variability of circadian movement of small trees across different taxonomic groups, growth forms and leaf anatomies. We surveyed a series of 18 full scans over a 12-h night period to measure nocturnal changes in shape simultaneously for an experimental setup of 22 plants representing different species. Resulting point clouds were evaluated by comparing changes in height percentiles of laser scanning points belonging to the canopy. Changes in crown shape were observed for all studied trees, but clearly distinguishable sleep movements are apparently rare. Ambient light conditions were continuously dark between sunset (7:30 p.m.) and sunrise (6:00 a.m.), but most changes in movement direction occurred during this period, thus most of the recorded changes in crown shape were probably not controlled by ambient light. The highest movement amplitudes, for periodic circadian movement around 2 cm were observed for Aesculus and Acer, compared to non-periodic continuous change in shape of 5 cm for Gleditschia and 2 cm for Fargesia. In several species we detected 2-4 h cycles of minor crown movement of 0.5-1 cm, which is close to the limit of our measurement accuracy. We present a conceptual framework for interpreting observed changes as a combination of circadian rhythm with a period close to 12 h, short-term oscillation repeated every 2-4 h, aperiodic continuous movement in one direction and measurement noise which we assume to be random. Observed movement patterns are interpreted within this framework, and connections with morphology and taxonomy are proposed. We confirm the existence of overnight "sleep" movement for some trees, but conclude that circadian movement is a variable phenomenon in plants, probably controlled by a complex combination of anatomical, physiological, and morphological factors.
Collapse
Affiliation(s)
- András Zlinszky
- Balaton Limnological Institute, Centre for Ecological Research, Hungarian Academy of Sciences, Tihany, Hungary
- Ecoinformatics and Biodiversity Section, Department of Bioscience, Aarhus University, Aarhus, Denmark
| | - Bence Molnár
- Department of Photogrammetry and Geoinformatics, Budapest University of Technology and Economics, Budapest, Hungary
| | - Anders S. Barfod
- Ecoinformatics and Biodiversity Section, Department of Bioscience, Aarhus University, Aarhus, Denmark
| |
Collapse
|
17
|
Chen Y, Schnitzer SA, Zhang Y, Fan Z, Goldstein G, Tomlinson KW, Lin H, Zhang J, Cao K. Physiological regulation and efficient xylem water transport regulate diurnal water and carbon balances of tropical lianas. Funct Ecol 2016. [DOI: 10.1111/1365-2435.12724] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ya‐Jun Chen
- Key Laboratory of Tropical Forest Ecology Xishuangbanna Tropical Botanical Garden Chinese Academy of Sciences Mengla Yunnan666303 China
- University of Chinese Academy of Sciences Beijing100049 China
| | - Stefan A. Schnitzer
- Department of Biological Sciences Marquette University PO Box 1881 Milwaukee WI53201 USA
| | - Yong‐Jiang Zhang
- Key Laboratory of Tropical Forest Ecology Xishuangbanna Tropical Botanical Garden Chinese Academy of Sciences Mengla Yunnan666303 China
| | - Ze‐Xin Fan
- Key Laboratory of Tropical Forest Ecology Xishuangbanna Tropical Botanical Garden Chinese Academy of Sciences Mengla Yunnan666303 China
| | - Guillermo Goldstein
- Department of Biology University of Miami PO Box 249118 Coral Gables FL33124 USA
| | - Kyle W. Tomlinson
- Center for Integrative Conservation Xishuangbanna Tropical Botanical Garden Chinese Academy of Sciences Mengla Yunnan666303 China
| | - Hua Lin
- Key Laboratory of Tropical Forest Ecology Xishuangbanna Tropical Botanical Garden Chinese Academy of Sciences Mengla Yunnan666303 China
| | - Jiao‐Lin Zhang
- Key Laboratory of Tropical Forest Ecology Xishuangbanna Tropical Botanical Garden Chinese Academy of Sciences Mengla Yunnan666303 China
| | - Kun‐Fang Cao
- Key Laboratory of Tropical Forest Ecology Xishuangbanna Tropical Botanical Garden Chinese Academy of Sciences Mengla Yunnan666303 China
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐bioresources Guangxi University Nanning Guangxi530004 China
| |
Collapse
|
18
|
A Regional Stable Carbon Isotope Dendro-Climatology from the South African Summer Rainfall Area. PLoS One 2016. [PMID: 27427912 DOI: 10.1371/journal.pone.0159361.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Carbon isotope analysis of four baobab (Adansonia digitata L.) trees from the Pafuri region of South Africa yielded a 1000-year proxy rainfall record. The Pafuri record age model was based on 17 radiocarbon dates, cross correlation of the climate record, and ring structures that were presumed to be annual for two of the trees. Here we present the analysis of five additional baobabs from the Mapungubwe region, approximately 200km west of Pafuri. The Mapungubwe chronology demonstrates that ring structures are not necessarily annually formed, and accordingly the Pafuri chronology is revised. Changes in intrinsic water-use efficiency indicate an active response by the trees to elevated atmospheric CO2, but this has little effect on the environmental signal. The revised Pafuri record, and the new Mapungubwe record correlate significantly with local rainfall. Both records confirm that the Medieval Warm Period was substantially wetter than present, and the Little Ice Age was the driest period in the last 1000 years. Although Mapungubwe is generally drier than Pafuri, both regions experience elevated rainfall peaking between AD 1570 and AD 1620 after which dry conditions persist in the Mapungubwe area until about AD 1840. Differences between the two records correlate with Agulhas Current sea-surface temperature variations suggesting east/west displacement of the temperate tropical trough system as an underlying mechanism. The Pafuri and Mapungubwe records are combined to provide a regional climate proxy record for the northern summer rainfall area of southern Africa.
Collapse
|
19
|
Woodborne S, Gandiwa P, Hall G, Patrut A, Finch J. A Regional Stable Carbon Isotope Dendro-Climatology from the South African Summer Rainfall Area. PLoS One 2016; 11:e0159361. [PMID: 27427912 PMCID: PMC4948844 DOI: 10.1371/journal.pone.0159361] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2015] [Accepted: 07/03/2016] [Indexed: 12/02/2022] Open
Abstract
Carbon isotope analysis of four baobab (Adansonia digitata L.) trees from the Pafuri region of South Africa yielded a 1000-year proxy rainfall record. The Pafuri record age model was based on 17 radiocarbon dates, cross correlation of the climate record, and ring structures that were presumed to be annual for two of the trees. Here we present the analysis of five additional baobabs from the Mapungubwe region, approximately 200km west of Pafuri. The Mapungubwe chronology demonstrates that ring structures are not necessarily annually formed, and accordingly the Pafuri chronology is revised. Changes in intrinsic water-use efficiency indicate an active response by the trees to elevated atmospheric CO2, but this has little effect on the environmental signal. The revised Pafuri record, and the new Mapungubwe record correlate significantly with local rainfall. Both records confirm that the Medieval Warm Period was substantially wetter than present, and the Little Ice Age was the driest period in the last 1000 years. Although Mapungubwe is generally drier than Pafuri, both regions experience elevated rainfall peaking between AD 1570 and AD 1620 after which dry conditions persist in the Mapungubwe area until about AD 1840. Differences between the two records correlate with Agulhas Current sea-surface temperature variations suggesting east/west displacement of the temperate tropical trough system as an underlying mechanism. The Pafuri and Mapungubwe records are combined to provide a regional climate proxy record for the northern summer rainfall area of southern Africa.
Collapse
Affiliation(s)
- Stephan Woodborne
- iThemba LABS, Private Bag 11, WITS, 2050, South Africa
- Mammal Research Institute, University of Pretoria, Private Bag X20, Hatfield, 0028, South Africa
- * E-mail:
| | - Patience Gandiwa
- Discipline of Geography, School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, Private Bag X01, Scottsville, 3209, Pietermaritzburg, South Africa
| | - Grant Hall
- Mammal Research Institute, University of Pretoria, Private Bag X20, Hatfield, 0028, South Africa
| | - Adrian Patrut
- Faculty of Chemistry, Babes-Bolyai University, Arany Janos 11, 400028, Cluj-Napoca, Romania
| | - Jemma Finch
- Discipline of Geography, School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, Private Bag X01, Scottsville, 3209, Pietermaritzburg, South Africa
| |
Collapse
|
20
|
Rosell JA. Bark thickness across the angiosperms: more than just fire. THE NEW PHYTOLOGIST 2016; 211:90-102. [PMID: 26890029 DOI: 10.1111/nph.13889] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 01/06/2016] [Indexed: 05/09/2023]
Abstract
Global variation in total bark thickness (TBT) is traditionally attributed to fire. However, bark is multifunctional, as reflected by its inner living and outer dead regions, meaning that, in addition to fire protection, other factors probably contribute to TBT variation. To address how fire, climate, and plant size contribute to variation in TBT, inner bark thickness (IBT) and outer bark thickness (OBT), I sampled 640 species spanning all major angiosperm clades and 18 sites with contrasting precipitation, temperature, and fire regime. Stem size was by far the main driver of variation in thickness, with environment being less important. IBT was closely correlated with stem diameter, probably for metabolic reasons, and, controlling for size, was thicker in drier and hotter environments, even fire-free ones, probably reflecting its water and photosynthate storage role. OBT was less closely correlated with size, and was thicker in drier, seasonal sites experiencing frequent fires. IBT and OBT covaried loosely and both contributed to overall TBT variation. Thickness variation was higher within than across sites and was evolutionarily labile. Given high within-site diversity and the multiple selective factors acting on TBT, continued study of the different drivers of variation in bark thickness is crucial to understand bark ecology.
Collapse
Affiliation(s)
- Julieta A Rosell
- Departamento de Ecología de la Biodiversidad, Instituto de Ecología, Universidad Nacional Autónoma de México, CP 04510, México, DF, Mexico
| |
Collapse
|
21
|
Lechthaler S, Robert EMR, Tonné N, Prusova A, Gerkema E, Van As H, Koedam N, Windt CW. Rhizophoraceae Mangrove Saplings Use Hypocotyl and Leaf Water Storage Capacity to Cope with Soil Water Salinity Changes. FRONTIERS IN PLANT SCIENCE 2016; 7:895. [PMID: 27446125 PMCID: PMC4921503 DOI: 10.3389/fpls.2016.00895] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 06/07/2016] [Indexed: 05/08/2023]
Abstract
Some of the most striking features of Rhizophoraceae mangrove saplings are their voluminous cylinder-shaped hypocotyls and thickened leaves. The hypocotyls are known to serve as floats during seed dispersal (hydrochory) and store nutrients that allow the seedling to root and settle. In this study we investigate to what degree the hypocotyls and leaves can serve as water reservoirs once seedlings have settled, helping the plant to buffer the rapid water potential changes that are typical for the mangrove environment. We exposed saplings of two Rhizophoraceae species to three levels of salinity (15, 30, and 0-5‰, in that sequence) while non-invasively monitoring changes in hypocotyl and leaf water content by means of mobile NMR sensors. As a proxy for water content, changes in hypocotyl diameter and leaf thickness were monitored by means of dendrometers. Hypocotyl diameter variations were also monitored in the field on a Rhizophora species. The saplings were able to buffer rapid rhizosphere salinity changes using water stored in hypocotyls and leaves, but the largest water storage capacity was found in the leaves. We conclude that in Rhizophora and Bruguiera the hypocotyl offers the bulk of water buffering capacity during the dispersal phase and directly after settlement when only few leaves are present. As saplings develop more leaves, the significance of the leaves as a water storage organ becomes larger than that of the hypocotyl.
Collapse
Affiliation(s)
- Silvia Lechthaler
- Department of Territorio e Sistemi Agro-Forestali, University of Padova, PadovaItaly
- Laboratory of Plant Biology and Nature Management, Department of Biology, Vrije Universiteit Brussel, BrusselsBelgium
| | - Elisabeth M. R. Robert
- Laboratory of Plant Biology and Nature Management, Department of Biology, Vrije Universiteit Brussel, BrusselsBelgium
- Laboratory of Wood Biology and Xylarium, Department of Wood Biology, Royal Museum for Central AfricaTervuren, Belgium
| | - Nathalie Tonné
- Laboratory of Plant Biology and Nature Management, Department of Biology, Vrije Universiteit Brussel, BrusselsBelgium
- Laboratory of Wood Biology and Xylarium, Department of Wood Biology, Royal Museum for Central AfricaTervuren, Belgium
| | - Alena Prusova
- Laboratory of Biophysics and Wageningen NMR Centre, Department of Agrotechnology & Food Sciences, Wageningen University, WageningenNetherlands
| | - Edo Gerkema
- Laboratory of Biophysics and Wageningen NMR Centre, Department of Agrotechnology & Food Sciences, Wageningen University, WageningenNetherlands
| | - Henk Van As
- Laboratory of Biophysics and Wageningen NMR Centre, Department of Agrotechnology & Food Sciences, Wageningen University, WageningenNetherlands
| | - Nico Koedam
- Laboratory of Plant Biology and Nature Management, Department of Biology, Vrije Universiteit Brussel, BrusselsBelgium
| | - Carel W. Windt
- IBG-2: Plant Sciences, Institute for Bio- and Geosciences, Forschungszentrum Jülich, JülichGermany
| |
Collapse
|
22
|
Chen YJ, Bongers F, Tomlinson K, Fan ZX, Lin H, Zhang SB, Zheng YL, Li YP, Cao KF, Zhang JL. Time lags between crown and basal sap flows in tropical lianas and co-occurring trees. TREE PHYSIOLOGY 2016; 36:736-747. [PMID: 26446267 DOI: 10.1093/treephys/tpv103] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 08/31/2015] [Indexed: 06/05/2023]
Abstract
Water storage in the stems of woody plants contributes to their responses to short-term water shortages. To estimate the contribution of water storage to the daily water budget of trees, time lags of sap flow between different positions of trunk are used as a proxy of stem water storage. In lianas, another large group of woody species, it has rarely been studied whether stored water functions in their daily water use, despite their increasing roles in the carbon and water dynamics of tropical forests caused by their increasing abundance. We hypothesized that lianas would exhibit large time lags due to their extremely long stems, wide vessels and large volume of parenchyma in the stem. We examined time lags in sap flow, diel changes of stem volumetric water content (VWC) and biophysical properties of sapwood of 19 lianas and 26 co-occurring trees from 27 species in 4 forests (karst, tropical seasonal, flood plain and savanna) during a wet season. The plants varied in height/length from <5 to >60 m. The results showed that lianas had significantly higher saturated water content (SWC) and much lower wood density than trees. Seven of 19 liana individuals had no time lags; in contrast, only 3 of 26 tree individuals had no time lags. In general, lianas had shorter time lags than trees in our data set, but this difference was not significant for our most conservative analyses. Across trees and lianas, time lag duration increased with diurnal maximum changeable VWC but was independent of the body size, path length, wood density and SWC. The results suggest that in most lianas, internal stem water storage contributes little to daily water budget, while trees may rely more on stored water in the stem.
Collapse
Affiliation(s)
- Ya-Jun Chen
- 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
| | - Frans Bongers
- Forest Ecology and Forest Management Group, Wageningen University, PO Box 47, 6700 AA Wageningen, The Netherlands
| | - Kyle Tomlinson
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China
| | - Ze-Xin Fan
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China
| | - Hua Lin
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China
| | - Shu-Bin Zhang
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China
| | - Yu-Long Zheng
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China
| | - Yang-Ping Li
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China
| | - Kun-Fang Cao
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, and College of Forestry, Guangxi University, Nanning, Guangxi 530004, China
| | - Jiao-Lin Zhang
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China
| |
Collapse
|
23
|
Puttonen E, Briese C, Mandlburger G, Wieser M, Pfennigbauer M, Zlinszky A, Pfeifer N. Quantification of Overnight Movement of Birch (Betula pendula) Branches and Foliage with Short Interval Terrestrial Laser Scanning. FRONTIERS IN PLANT SCIENCE 2016; 7:222. [PMID: 26973668 PMCID: PMC4770040 DOI: 10.3389/fpls.2016.00222] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2015] [Accepted: 02/09/2016] [Indexed: 05/25/2023]
Abstract
The goal of the study was to determine circadian movements of silver birch (Petula Bendula) branches and foliage detected with terrestrial laser scanning (TLS). The study consisted of two geographically separate experiments conducted in Finland and in Austria. Both experiments were carried out at the same time of the year and under similar outdoor conditions. Experiments consisted of 14 (Finland) and 77 (Austria) individual laser scans taken between sunset and sunrise. The resulting point clouds were used in creating a time series of branch movements. In the Finnish data, the vertical movement of the whole tree crown was monitored due to low volumetric point density. In the Austrian data, movements of manually selected representative points on branches were monitored. The movements were monitored from dusk until morning hours in order to avoid daytime wind effects. The results indicated that height deciles of the Finnish birch crown had vertical movements between -10.0 and 5.0 cm compared to the situation at sunset. In the Austrian data, the maximum detected representative point movement was 10.0 cm. The temporal development of the movements followed a highly similar pattern in both experiments, with the maximum movements occurring about an hour and a half before (Austria) or around (Finland) sunrise. The results demonstrate the potential of terrestrial laser scanning measurements in support of chronobiology.
Collapse
Affiliation(s)
- Eetu Puttonen
- Department of Remote Sensing and Photogrammetry, Finnish Geospatial Research Institute, National Land Survey of FinlandMasala, Finland
- Department of Remote Sensing and Photogrammetry, Centre of Excellence in Laser Scanning Research, National Land Survey of FinlandMasala, Finland
| | - Christian Briese
- Department of Geodesy and Geoinformation, Technische Universität WienVienna, Austria
- EODC Earth Observation Data Centre for Water Resources MonitoringVienna, Austria
| | - Gottfried Mandlburger
- Department of Geodesy and Geoinformation, Technische Universität WienVienna, Austria
| | - Martin Wieser
- Department of Geodesy and Geoinformation, Technische Universität WienVienna, Austria
| | | | - András Zlinszky
- Balaton Limnological Institute, Centre for Ecological Research, Hungarian Academy of SciencesTihany, Hungary
| | - Norbert Pfeifer
- Department of Geodesy and Geoinformation, Technische Universität WienVienna, Austria
| |
Collapse
|
24
|
Experimental climate warming enforces seed dormancy in South African Proteaceae but seedling drought resilience exceeds summer drought periods. Oecologia 2014; 177:1103-16. [PMID: 25502439 DOI: 10.1007/s00442-014-3173-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Accepted: 11/25/2014] [Indexed: 10/24/2022]
Abstract
Two hypotheses-that elevated night-time temperatures due to climate warming would enforce post-fire dormancy of Proteaceae seed due to low moisture, and that periods without rain during summer would exceed desiccation periods tolerated by Proteaceae seedlings-were tested empirically. Enforced dormancy, i.e., the inability to germinate due to an environmental restraint, was tested by measuring seed germination in 11 Proteaceae species in experimental mesocosms whose soils were artificially elevated by 1.4 and 3.5 °C above ambient by far-red wavelength filtered infrared lamps. Diminished totality of germination and velocities were observed in 91 and 64%, respectively, of the Proteaceae species tested. Drought resilience was tested in one-year-old seedlings of 16 Proteaceae species by withholding water from potted plants during summer in a greenhouse. The most drought-resilient Proteaceae species displayed the lowest initial transpiration rates at field capacity, the smallest declines in transpiration rate with decreasing soil water content, and the lowest water losses by transpiration. Projected drought periods leading to the complete cessation of transpiration in all Proteaceae species greatly exceeded the number of days without rain per month during summer in the current distribution ranges of those species. It was therefore concluded that enforced seed dormancy induced by elevated night-time temperatures is the post-fire recruitment stage of Proteaceae that is most sensitive to climate warming.
Collapse
|
25
|
Evans M, Aubriot X, Hearn D, Lanciaux M, Lavergne S, Cruaud C, Lowry PP, Haevermans T. Insights on the Evolution of Plant Succulence from a Remarkable Radiation in Madagascar (Euphorbia). Syst Biol 2014; 63:697-711. [DOI: 10.1093/sysbio/syu035] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
26
|
Spicer R. Symplasmic networks in secondary vascular tissues: parenchyma distribution and activity supporting long-distance transport. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:1829-48. [PMID: 24453225 DOI: 10.1093/jxb/ert459] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Stems that develop secondary vascular tissue (i.e. xylem and phloem derived from the vascular cambium) have unique demands on transport owing to their mass and longevity. Transport of water and assimilates must occur over long distances, while the increasing physical separation of xylem and phloem requires radial transport. Developing secondary tissue is itself a strong sink positioned between xylem and phloem along the entire length of the stem, and the integrity of these transport tissues must be maintained and protected for years if not decades. Parenchyma cells form an interconnected three-dimensional lattice throughout secondary xylem and phloem and perform critical roles in all of these tasks, yet our understanding of their physiology, the nature of their symplasmic connections, and their activity at the symplast-apoplast interface is very limited. This review highlights key historical work as well as current research on the structure and function of parenchyma in secondary vascular tissue in the hopes of spurring renewed interest in this area, which has important implications for whole-plant transport processes and resource partitioning.
Collapse
Affiliation(s)
- Rachel Spicer
- Department of Botany, Connecticut College, New London, CT 06320, USA
| |
Collapse
|
27
|
Ward EJ, Bell DM, Clark JS, Oren R. Hydraulic time constants for transpiration of loblolly pine at a free-air carbon dioxide enrichment site. TREE PHYSIOLOGY 2013; 33:123-134. [PMID: 23192973 DOI: 10.1093/treephys/tps114] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The impact of stored water on estimates of transpiration from scaled sap flux measurements was assessed in mature Pinus taeda (L.) at the Duke Free-Air CO(2) Enrichment (FACE) site. We used a simple hydraulic model with measurements of sap flux (J) at breast height and the base of the live crown for 26 trees over 6 months to examine the effects of elevated CO(2) (eCO(2)) and fertilization (N(F)) treatments, as well as temporal variation in soil moisture (M(()(t)())), on estimates of the hydraulic time constant (κ). At low M(()(t)()), there was little (<12%) difference in κ of different treatments. At high M(()(t)()), differences were much greater, with κ reductions of 27, 52 and 34% in eCO(2), N(F) and eCO(2) × N(F) respective to the control. Incorporating κ with these effects into the analysis of a larger data set of previous J measurements at this site (1998-2008) improved agreement between modeled and measured values in 92% of cases. However, a simplified calibration of κ that neglected treatment and soil moisture effects performed more dependably, improving agreement in 98% of cases. Incorporating κ had the effect of increasing estimates of reference stomatal conductance at 1 kPa vapor pressure deficit (VPD) and saturating photosynthetic active radiation (PAR) an average of 12-14%, while increasing estimated sensitivities to VPD and PAR. A computationally efficient hydraulic model, such as the one presented here, incorporated into a hierarchical model of stomatal conductance presents a novel approach to including hydraulic time constants in estimates of stomatal responses from long-term sap flux data sets.
Collapse
Affiliation(s)
- Eric J Ward
- Nicholas School of the Environment, Duke University, Durham, NC 27708, USA.
| | | | | | | |
Collapse
|
28
|
Zhang JL, Poorter L, Hao GY, Cao KF. Photosynthetic thermotolerance of woody savanna species in China is correlated with leaf life span. ANNALS OF BOTANY 2012; 110:1027-33. [PMID: 22875810 PMCID: PMC3448426 DOI: 10.1093/aob/mcs172] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Accepted: 06/11/2012] [Indexed: 05/04/2023]
Abstract
BACKGROUND AND AIMS Photosynthetic thermotolerance (PT) is important for plant survival in tropical and sub-tropical savannas. However, little is known about thermotolerance of tropical and sub-tropical wild plants and its association with leaf phenology and persistence. Longer-lived leaves of savanna plants may experience a higher risk of heat stress. Foliar Ca is related to cell integrity of leaves under stresses. In this study it is hypothesized that (1) species with leaf flushing in the hot-dry season have greater PT than those with leaf flushing in the rainy season; and (2) PT correlates positively with leaf life span, leaf mass per unit area (LMA) and foliar Ca concentration ([Ca]) across woody savanna species. METHODS The temperature-dependent increase in minimum fluorescence was measured to assess PT, together with leaf dynamics, LMA and [Ca] for a total of 24 woody species differing in leaf flushing time in a valley-type savanna in south-west China. KEY RESULTS The PT of the woody savanna species with leaf flushing in the hot-dry season was greater than that of those with leaf flushing in the rainy season. Thermotolerance was positively associated with leaf life span and [Ca] for all species irrespective of the time of flushing. The associations of PT with leaf life span and [Ca] were evolutionarily correlated. Thermotolerance was, however, independent of LMA. CONCLUSIONS Chinese savanna woody species are adapted to hot-dry habitats. However, the current maximum leaf temperature during extreme heat stress (44·3 °C) is close to the critical temperature of photosystem II (45·2 °C); future global warming may increase the risk of heat damage to the photosynthetic apparatus of Chinese savanna species.
Collapse
Affiliation(s)
- Jiao-Lin Zhang
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China
| | - L. Poorter
- Forest Ecology and Forest Management Group, Wageningen University, PO Box 47, 6700 AA Wageningen, The Netherlands
| | - Guang-You Hao
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China
| | - Kun-Fang Cao
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China
- Yuanjiang Dry-Hot-Valley Ecological Station, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Yuanjiang, Yunnan 653300, China
| |
Collapse
|
29
|
Do FC, Isarangkool Na Ayutthaya S, Rocheteau A. Transient thermal dissipation method for xylem sap flow measurement: implementation with a single probe. TREE PHYSIOLOGY 2011; 31:369-380. [PMID: 21498407 DOI: 10.1093/treephys/tpr020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Comparisons of tree water relations between treatments, species and sites are facilitated by the use of simple and low-cost measurements of xylem sap flow rates. The transient thermal dissipation (TTD) method is a variant of the constant thermal dissipation (CTD) method of Granier. It has the advantages of limiting thermal interference and of saving electrical energy. Here, our concern was to test a new step towards simplicity and low cost: the applicability of the TTD method with a single probe, i.e., without a reference sensor, following a cycle of 10 min heating and 10 min cooling, and using the same thermal index and multi-species calibration previously assessed with a dual probe. First, the responses of the dual and single probes were compared in an artificial hydraulic column of sawdust in the laboratory over a complete range of flux densities, from 0.3 to 4.0 l dm⁻² h⁻¹. Second, diurnal kinetics were compared in a young tree with rapid changes in the sapwood reference temperature of up to 5 °C h⁻¹ for 5 consecutive days. With a relatively stable reference temperature, laboratory results showed that a single probe yielded the same temperature signal and thermal index as a dual probe for the full range of sap flux densities. Within the tree, the cooled temperature of the heated probe, linearly interpolated, proved to be an accurate indicator of the change in the reference temperature over time. Logically, the temperature signals and estimates of sap flux density with the single probe did not differ from the dual-sensor measurements when the cooled temperature was interpolated. Additionally, the responses of the thermal index, yielded in the hydraulic experiment with the sawdust column, fell within the variability of the multi-species calibration. This result supports the previous assessment of a non-species-specific calibration for the TTD method with diffuse porous media. In conclusion, our results showed that the TTD method can be directly applied with a single probe. Limitations and possible future progress are pointed out. This measurement system is probably the simplest technique currently available to measure xylem sap flow.
Collapse
Affiliation(s)
- F C Do
- IRD, UMR Eco&Sols, Campus SupAgro-INRA, F-34060 Montpellier, France.
| | | | | |
Collapse
|
30
|
Isarangkool Na Ayutthaya S, Do FC, Pannengpetch K, Junjittakarn J, Maeght JL, Rocheteau A, Cochard H. Transient thermal dissipation method of xylem sap flow measurement: multi-species calibration and field evaluation. TREE PHYSIOLOGY 2010; 30:139-48. [PMID: 19864260 DOI: 10.1093/treephys/tpp092] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The transient thermal dissipation (TTD) method developed by Do and Rocheteau (2002b) is a close evolution of the original constant thermal dissipation (CTD) method of Granier (1985). The TTD method has the advantage of limiting the influence of passive natural temperature gradients and of yielding more stable zero-flux references at night. By analogy with the CTD method, the transient method was first calibrated on synthetic porous material (sawdust) on the assumption that the relationship was independent of the woody species. Here, our concern was to test the latter hypothesis with a 10-min heating time in three tropical species: Hevea brasiliensis Müll. Arg., Mangifera indica L. and Citrus maxima Merr. A complementary objective was to compare the field estimates of daily transpiration for mature rubber trees with estimates based on a simplified soil water balance in the dry season. The calibration experiments were carried out in the laboratory on cut stems using an HPFM device and gravimetric control of water flow up to 5 L dm(-2) h(-1). Nineteen response curves were assessed on fully conductive xylem, combining 11 cut stems and two probes. The field evaluation comprised five periods from November 2007 to February 2008. Estimates of daily transpiration from the measurement of sap flow were based on the 41 sensors set up on 11 trees. Soil water depletion was monitored by neutron probe and 12 access tubes to a depth of 1.8 m. The calibrations confirmed that the response of the transient thermal index to flow density was independent of the woody species that were tested. The best fit was a simple linear response (R(2) = 0.88, n = 276 and P < 0.0001). The previous calibration performed by Do and Rocheteau (2002b) on sawdust fell within the variability of the multi-species calibration; however, there were substantial differences with the average curve at extreme flow rates. Field comparison with soil water depletion in the dry season validated to a reasonable extent the absolute estimates of transpiration acquired with the 10-min TTD method. In conclusion, evidence for the independence of calibration from woody species and the simple linear response of the thermal index strengthen the interest of the TTD method with 10-min heating.
Collapse
|
31
|
Sperry JS, Meinzer FC, McCulloh KA. Safety and efficiency conflicts in hydraulic architecture: scaling from tissues to trees. PLANT, CELL & ENVIRONMENT 2008; 31:632-45. [PMID: 18088335 DOI: 10.1111/j.1365-3040.2007.01765.x] [Citation(s) in RCA: 207] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Tree hydraulic architecture exhibits patterns that propagate from tissue to tree scales. A challenge is to make sense of these patterns in terms of trade-offs and adaptations. The universal trend for conduits per area to decrease with increasing conduit diameter below the theoretical packing limit may reflect the compromise between maximizing the area for conduction versus mechanical support and storage. Variation in conduit diameter may have two complementary influences: one being compromises between efficiency and safety and the other being that conduit tapering within a tree maximizes conductance per growth investment. Area-preserving branching may be a mechanical constraint, preventing otherwise more efficient top-heavy trees. In combination, these trends beget another: trees have more, narrower conduits moving from trunks to terminal branches. This pattern: (1) increases the efficiency of tree water conduction; (2) minimizes (but does not eliminate) any hydraulic limitation on the productivity or tissue growth with tree height; and (3) is consistent with the scaling of tree conductance and sap flow with size. We find no hydraulic reason why tree height should scale with a basal diameter to the two-thirds power as recently claimed; it is probably another mechanical constraint as originally proposed. The buffering effect of capacitance on the magnitude of transpiration-induced xylem tension appears to be coupled to cavitation resistance, possibly alleviating safety versus efficiency trade-offs.
Collapse
Affiliation(s)
- John S Sperry
- Department of Biology, University of Utah, 257 South 1400 East, Salt Lake City, UT 84112, USA.
| | | | | |
Collapse
|