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Griffani DS, Rognon P, Farquhar GD. The role of thermodiffusion in transpiration. THE NEW PHYTOLOGIST 2024; 243:1301-1311. [PMID: 38453691 DOI: 10.1111/nph.19642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 01/28/2024] [Indexed: 03/09/2024]
Abstract
Plant leaf temperatures can differ from ambient air temperatures. A temperature gradient in a gas mixture gives rise to a phenomenon known as thermodiffusion, which operates in addition to ordinary diffusion. Whilst transpiration is generally understood to be driven solely by the ordinary diffusion of water vapour along a concentration gradient, we consider the implications of thermodiffusion for transpiration. We develop a new modelling framework that introduces the effects of thermodiffusion on the transpiration rate, E. By applying this framework, we quantify the proportion of E attributable to thermodiffusion for a set of physiological and environmental conditions, varied over a wide range. Thermodiffusion is found to be most significant (in some cases > 30% of E) when a leaf-to-air temperature difference coincides with a relatively small water vapour concentration difference across the boundary layer; a boundary layer conductance that is large as compared to the stomatal conductance; or a relatively low transpiration rate. Thermodiffusion also alters the conditions required for the onset of reverse transpiration, and the rate at which this water vapour uptake occurs.
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Affiliation(s)
- Danielle S Griffani
- Faculty of Science and Engineering, Southern Cross University, East Lismore, NSW, 2480, Australia
| | - Pierre Rognon
- School of Civil Engineering, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Graham D Farquhar
- Research School of Biology, Australian National University, Acton, ACT, 2601, Australia
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2
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Heredia A, Benítez JJ, González Moreno A, Domínguez E. Revisiting plant cuticle biophysics. THE NEW PHYTOLOGIST 2024. [PMID: 39061101 DOI: 10.1111/nph.20009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2024] [Accepted: 07/08/2024] [Indexed: 07/28/2024]
Abstract
The plant cuticle is located at the interface of the plant with the environment, thus acting as a protective barrier against biotic and abiotic external stress factors, and regulating water loss. Additionally, it modulates mechanical stresses derived from internal tissues and also from the environment. Recent advances in the understanding of the hydric, mechanical, thermal, and, to a lower extent, optical and electric properties of the cuticle, as well as their phenomenological connections and relationships are reviewed. An equilibrium based on the interaction among the different biophysical properties is essential to ensure plant growth and development. The notable variability reported in cuticle geometry, surface topography, and microchemistry affects the analysis of some biophysical properties of the cuticle. This review aimed to provide an updated view of the plant cuticle, understood as a modification of the cell wall, in order to establish the state-of-the-art biophysics of the plant cuticle, and to serve as an inspiration for future research in the field.
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Affiliation(s)
- Antonio Heredia
- Departamento de Biología Molecular y Bioquímica, Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora", Universidad de Málaga-Consejo Superior de Investigaciones Científicas, Universidad de Málaga, E-29010, Málaga, Spain
| | - José J Benítez
- Instituto de Ciencia de Materiales de Sevilla, Centro Mixto Consejo Superior de Investigaciones Científicas-Universidad de Sevilla, E-41092, Seville, Spain
| | - Ana González Moreno
- Departamento de Biología Molecular y Bioquímica, Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora", Universidad de Málaga-Consejo Superior de Investigaciones Científicas, Universidad de Málaga, E-29010, Málaga, Spain
| | - Eva Domínguez
- Departamento de Mejora Genética y Biotecnología, Estación Experimental La Mayora, Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora", Universidad de Málaga-Consejo Superior de Investigaciones Científicas, E-29750, Málaga, Spain
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3
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Fradera-Soler M, Mravec J, Schulz A, Taboryski R, Jørgensen B, Grace OM. Revisiting an ecophysiological oddity: Hydathode-mediated foliar water uptake in Crassula species from southern Africa. PLANT, CELL & ENVIRONMENT 2024; 47:460-481. [PMID: 37876364 DOI: 10.1111/pce.14743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 10/10/2023] [Accepted: 10/16/2023] [Indexed: 10/26/2023]
Abstract
Hydathodes are usually associated with water exudation in plants. However, foliar water uptake (FWU) through the hydathodes has long been suspected in the leaf-succulent genus Crassula (Crassulaceae), a highly diverse group in southern Africa, and, to our knowledge, no empirical observations exist in the literature that unequivocally link FWU to hydathodes in this genus. FWU is expected to be particularly beneficial on the arid western side of southern Africa, where up to 50% of Crassula species occur and where periodically high air humidity leads to fog and/or dew formation. To investigate if hydathode-mediated FWU is operational in different Crassula species, we used the apoplastic fluorescent tracer Lucifer Yellow in combination with different imaging techniques. Our images of dye-treated leaves confirm that hydathode-mediated FWU does indeed occur in Crassula and that it might be widespread across the genus. Hydathodes in Crassula serve as moisture-harvesting structures, besides their more common purpose of guttation, an adaptation that has likely played an important role in the evolutionary history of the genus. Our observations suggest that ability for FWU is independent of geographical distribution and not restricted to arid environments under fog influence, as FWU is also operational in Crassula species from the rather humid eastern side of southern Africa. Our observations point towards no apparent link between FWU ability and overall leaf surface wettability in Crassula. Instead, the hierarchically sculptured leaf surfaces of several Crassula species may facilitate FWU due to hydrophilic leaf surface microdomains, even in seemingly hydrophobic species. Overall, these results confirm the ecophysiological relevance of hydathode-mediated FWU in Crassula and reassert the importance of atmospheric humidity for some arid-adapted plant groups.
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Affiliation(s)
- Marc Fradera-Soler
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
- Royal Botanic Gardens, Kew, Richmond, Surrey, UK
| | - Jozef Mravec
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
- Institute of Plant Genetics and Biotechnology, Slovak Academy of Sciences, Plant Science and Biodiversity Center, Nitra, Slovakia
| | - Alexander Schulz
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Rafael Taboryski
- National Centre for Nano Fabrication and Characterization (DTU Nanolab), Technical University of Denmark, Lyngby, Denmark
| | - Bodil Jørgensen
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Olwen M Grace
- Royal Botanic Gardens, Kew, Richmond, Surrey, UK
- Royal Botanic Garden Edinburgh, Edinburgh, UK
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4
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Beckett HAA, Webb D, Turner M, Sheppard A, Ball MC. Bark water uptake through lenticels increases stem hydration and contributes to stem swelling. PLANT, CELL & ENVIRONMENT 2024; 47:72-90. [PMID: 37811590 DOI: 10.1111/pce.14733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 09/26/2023] [Indexed: 10/10/2023]
Abstract
Foliar water uptake can recharge water storage tissue and enable greater hydration than through access to soil water alone; however, few studies have explored the role of the bark in facilitating water uptake. We investigated pathways and dynamics of bark water uptake (BWU) in stems of the mangrove Avicennia marina. We provide novel evidence that specific entry points control dynamics of water uptake through the outer bark surface. Furthermore, using a fluorescent symplastic tracer dye we provide the first evidence that lenticels on the outer bark surface facilitate BWU, thus increasing stem water content by up to 3.7%. X-ray micro-computed tomography showed that BWU was sufficient to cause measurable swelling of stem tissue layers increasing whole stem cross-sectional area by 0.83 mm2 or 2.8%, implicating it as a contributor to the diel patterns of water storage recharge that buffer xylem water potential and maintain hydration of living tissue.
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Affiliation(s)
- Holly A A Beckett
- Plant Science Division, Research School of Biology, Australian National University, Canberra, Australia
| | - Daryl Webb
- Centre for Advanced Microscopy, Australian National University, Canberra, Australia
| | - Michael Turner
- Department of Applied Mathematics, Research School of Physics, Australian National University, Canberra, Australia
| | - Adrian Sheppard
- Department of Applied Mathematics, Research School of Physics, Australian National University, Canberra, Australia
| | - Marilyn C Ball
- Plant Science Division, Research School of Biology, Australian National University, Canberra, Australia
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5
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Fonollá A, Hormaza JI, Losada JM. Foliar Pectins and Physiology of Diploid and Autotetraploid Mango Genotypes under Water Stress. PLANTS (BASEL, SWITZERLAND) 2023; 12:3738. [PMID: 37960094 PMCID: PMC10650725 DOI: 10.3390/plants12213738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2023] [Revised: 10/24/2023] [Accepted: 10/24/2023] [Indexed: 11/15/2023]
Abstract
The cultivation of mango in Mediterranean-type climates is challenged by the depletion of freshwater. Polyploids are alternative genotypes with potential greater water use efficiency, but field evaluations of the anatomy and physiology of conspecific adult polyploid trees under water stress remain poorly explored. We combined field anatomical evaluations with measurements of leaf water potential (Ψl) and stomatal conductance (Gs) comparing one diploid and one autotetraploid tree per treatment with and without irrigation during dry summers (when fruits develop). Autotetraploid leaves displayed lower Ψl and Gs in both treatments, but the lack of irrigation only affected Gs. Foliar cells of the adaxial epidermis and the spongy mesophyll contained linear pectin epitopes, whereas branched pectins were localized in the abaxial epidermis, the chloroplast membrane, and the sieve tube elements of the phloem. Cell and fruit organ size was larger in autotetraploid than in diploid mango trees, but the sugar content in the fruits was similar between both cytotypes. Specific cell wall hygroscopic pectins correlate with more stable Ψl of autotetraploid leaves under soil water shortage, keeping lower Gs compared with diploids. These preliminary results point to diploids as more susceptible to water deficits than tetraploids.
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Affiliation(s)
| | | | - Juan M. Losada
- Institute for Mediterranean and Subtropical Horticulture ‘La Mayora’ (IHSM La Mayora—CSIC—UMA), Avda. Dr. Wienberg s/n, 29750 Malaga, Spain; (A.F.); (J.I.H.)
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Chin ARO, Guzmán-Delgado P, Görlich A, HilleRisLambers J. Towards multivariate functional trait syndromes: Predicting foliar water uptake in trees. Ecology 2023; 104:e4112. [PMID: 37252804 DOI: 10.1002/ecy.4112] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 05/10/2023] [Accepted: 05/18/2023] [Indexed: 06/01/2023]
Abstract
Analysis of functional traits is a cornerstone of ecology, yet individual traits seldom explain useful amounts of variation in species distribution or climatic tolerance, and their functional significance is rarely validated experimentally. Multivariate suites of interacting traits could build an understanding of ecological processes and improve our ability to make sound predictions of species success in our rapidly changing world. We use foliar water uptake capacity as a case study because it is increasingly considered to be a key functional trait in plant ecology due to its importance for stress-tolerance physiology. However, the traits behind the trait, that is, the features of leaves that determine variation in foliar water uptake rates, have not been assembled into a widely applicable framework for uptake prediction. Focusing on trees, we investigated relationships among 25 structural traits, leaf osmotic potential (a source of free energy to draw water into leaves), and foliar water uptake in 10 diverse angiosperm and conifer species. We identified consistent, multitrait "uptake syndromes" for both angiosperm and conifer trees, with differences in key traits revealing suspected differences in the water entry route between these two clades and an evolutionarily significant divergence in the function of homologous structures. A literature review of uptake-associated functional traits, which largely documents similar univariate relationships, provides additional support for our proposed "uptake syndrome." Importantly, more than half of shared traits had opposite-direction influences on the capacity of leaves to absorb water in angiosperms and conifers. Taxonomically targeted multivariate trait syndromes provide a useful tool for trait selection in ecological research, while highlighting the importance of micro-traits and the physiological verification of their function for advancing trait-based ecology.
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Affiliation(s)
- Alana R O Chin
- Plant Ecology Group, Institute of Integrative Biology, ETH-Zürich, Zürich, Switzerland
| | - Paula Guzmán-Delgado
- Department of Plant Sciences, University of California, Davis, Davis, California, USA
| | - Anna Görlich
- Plant Ecology Group, Institute of Integrative Biology, ETH-Zürich, Zürich, Switzerland
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7
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Bei Z, Zhang X, Tian X. The Mechanism by Which Umbrella-Shaped Ratchet Trichomes on the Elaeagnus angustifolia Leaf Surface Collect Water and Reflect Light. BIOLOGY 2023; 12:1024. [PMID: 37508453 PMCID: PMC10376016 DOI: 10.3390/biology12071024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 07/18/2023] [Accepted: 07/18/2023] [Indexed: 07/30/2023]
Abstract
Leaves are essential for plants, enabling photosynthesis and transpiration. In arid regions, water availability limits plant growth. Some plants, like Elaeagnus angustifolia, a sandy sub-tree species widely distributed in arid and semi-arid regions, have unique leaf structures to reduce water loss and solar radiation. Here, we describe the leaves of Elaeagnus angustifolia L., with special functioning trichomes. Through leaf submicroscopic structure observation, in situ water collection experiments, photosynthesis measurements, and reflection spectrum analysis, we investigated E. angustifolia leaves, focusing on their functioning trichomes. These trichomes capture water vapor, reflect UV and NIR light, and possess a 3D interface structure composed of 1D and 2D structures. The 1D conical structure captures water droplets, which are then gathered by the radial conical structure and guided towards the stomata through wedge-shaped grooves on the 2D umbrella structure. The trichomes also reflect sunlight, with micropapillae reflecting UV light and the umbrella structure reflecting NIR light. These mechanisms reduce leaf temperature, respiration, and water transpiration, protecting against solar radiation damage. This study provides insights into water collection and light-reflection mechanisms, revealing adaptive strategies of plants with large leaves in arid regions.
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Affiliation(s)
- Zhanlin Bei
- School of Life Sciences, Nanjing University, Nanjing 210023, China
- School of Biological Science and Engineering, North Minzu University, Yinchuan 750021, China
| | - Xin Zhang
- School of Biological Science and Engineering, North Minzu University, Yinchuan 750021, China
| | - Xingjun Tian
- School of Life Sciences, Nanjing University, Nanjing 210023, China
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8
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Losso A, Dämon B, Hacke U, Mayr S. High potential for foliar water uptake in early stages of leaf development of three woody angiosperms. PHYSIOLOGIA PLANTARUM 2023; 175:e13961. [PMID: 37341178 PMCID: PMC10953411 DOI: 10.1111/ppl.13961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 06/06/2023] [Accepted: 06/16/2023] [Indexed: 06/22/2023]
Abstract
Foliar water uptake (FWU) is a widespread mechanism that may help plants cope with drought stress in a wide range of ecosystems. FWU can be affected by various leaf traits, which change during leaf development. We exposed cut and dehydrated leaves to rainwater and measured FWU, changes in leaf water potential after 19 h of FWU (ΔΨ), minimum leaf conductance (gmin ), and leaf wettability (abaxial and adaxial) of leaves of Acer platanoides, Fagus sylvatica, and Sambucus nigra at three developmental stages: unfolding (2-5-day-old), young (1.5-week-old) and mature leaves (8-week-old). FWU and gmin were higher in younger leaves. ΔΨ corresponded to FWU and gmin in all cases but mature leaves of F. sylvatica, where ΔΨ was highest. Most leaves were highly wettable, and at least one leaf surface (adaxial or abaxial) showed a decrease in wettability from unfolding to mature leaves. Young leaves of all studied species showed FWU (unfolding leaves: 14.8 ± 1.1 μmol m-2 s-1 ), which may improve plant water status and thus counterbalance spring transpirational losses due to high gmin . The high wettability of young leaves probably supported FWU. We observed particularly high FWU and respective high ΔΨ in older leaves of F. sylvatica, possibly aided by trichomes.
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Affiliation(s)
- Adriano Losso
- Department of BotanyUniversity of InnsbruckInnsbruckAustria
| | - Birgit Dämon
- Department of BotanyUniversity of InnsbruckInnsbruckAustria
| | - Uwe Hacke
- Department of Renewable ResourcesUniversity of AlbertaEdmontonAlbertaCanada
| | - Stefan Mayr
- Department of BotanyUniversity of InnsbruckInnsbruckAustria
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9
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Roth-Nebelsick A, Hacke UG, Voigt D, Schreiber SG, Krause M. Foliar water uptake in Pinus species depends on needle age and stomatal wax structures. ANNALS OF BOTANY 2023; 131:287-300. [PMID: 36420705 PMCID: PMC9992939 DOI: 10.1093/aob/mcac141] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2022] [Accepted: 11/22/2022] [Indexed: 06/16/2023]
Abstract
BACKGROUND AND AIMS Foliar water uptake (FWU) has been documented in many species and is increasingly recognized as a non-trivial factor in plant-water relationships. However, it remains unknown whether FWU is a widespread phenomenon in Pinus species, and how it may relate to needle traits such as the form and structure of stomatal wax plugs. In this contribution, these questions were addressed by studying FWU in current-year and 1-year-old needles of seven Pinus species. METHODS We monitored FWU gravimetrically and analysed the needle surface via cryo-scanning electron microscopy. Additionally, we considered the effect of artificial wax erosion by application of the surfactant Triton X-100, which is able to alter wax crystals. KEY RESULTS The results show for all species that (1) FWU occurred, (2) FWU is higher in old needles compared to young needles and (3) there is substantial erosion of stomatal wax plugs in old needles. FWU was highest in Pinus canariensis, which has a thin stomatal wax plug. Surfactant treatment enhanced FWU. CONCLUSIONS The results of this study provide evidence for (1) widespread FWU in Pinus, (2) the influence of stomatal wax plugs on FWU and (3) age-related needle surface erosion.
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Affiliation(s)
| | - Uwe G Hacke
- Department of Renewable Resources, University of Alberta, 442 Earth Sciences Building, Edmonton, Alberta, T6G 2E3, Canada
| | - Dagmar Voigt
- Technische Universität Dresden, Faculty of Biology, Institute of Botany, 01062 Dresden, Germany
| | - Stefan G Schreiber
- EnviroStats Solutions Inc., 4715 117A ST NW, Edmonton, Alberta, T6H 3R9, Canada
| | - Matthias Krause
- State Museum of Natural History, Rosenstein 1, 70191 Stuttgart, Germany
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Li C, Mo Y, Wang N, Xing L, Qu Y, Chen Y, Yuan Z, Ali A, Qi J, Fernández V, Wang Y, Kopittke PM. The overlooked functions of trichomes: Water absorption and metal detoxication. PLANT, CELL & ENVIRONMENT 2023; 46:669-687. [PMID: 36581782 DOI: 10.1111/pce.14530] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 12/20/2022] [Accepted: 12/28/2022] [Indexed: 06/17/2023]
Abstract
Trichomes are epidermal outgrowths on plant shoots. Their roles in protecting plants against herbivores and in the biosynthesis of specialized metabolites have long been recognized. Recently, studies are increasingly showing that trichomes also play important roles in water absorption and metal detoxication, with these roles having important implications for ecology, the environment, and agriculture. However, these two functions of trichomes have been largely overlooked and much remains unknown. In this review, we show that the trichomes of 37 plant species belonging to 14 plant families are involved in water absorption, while the trichomes of 33 species from 13 families are capable of sequestering metals within their trichomes. The ability of trichomes to absorb water results from their decreased hydrophobicity compared to the remainder of the leaf surface as well as the presence of special structures for collecting and absorbing water. In contrast, the metal detoxication function of trichomes results not only from the good connection of their basal cells to the underlying vascular tissues, but also from the presence of metal-chelating ligands and transporters within the trichomes themselves. Knowledge gaps and critical future research questions regarding these two trichome functions are highlighted. This review improves our understanding on trichomes.
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Affiliation(s)
- Cui Li
- School of Ecology and Environment, Northwestern Polytechnical University, Xi'an, China
| | - Yingying Mo
- School of Ecology and Environment, Northwestern Polytechnical University, Xi'an, China
| | - Nina Wang
- School of Ecology and Environment, Northwestern Polytechnical University, Xi'an, China
| | - Longyi Xing
- School of Ecology and Environment, Northwestern Polytechnical University, Xi'an, China
| | - Yang Qu
- Baoji Academy of Agriculture Sciences, Baoji, China
| | - Yanlong Chen
- School of Ecology and Environment, Northwestern Polytechnical University, Xi'an, China
| | - Zuoqiang Yuan
- School of Ecology and Environment, Northwestern Polytechnical University, Xi'an, China
| | - Arshad Ali
- College of Life Sciences, Hebei University, Hebei, China
| | - Jiyan Qi
- School of Ecology and Environment, Northwestern Polytechnical University, Xi'an, China
| | - Victoria Fernández
- School of Forest Engineering, Technical University of Madrid, Madrid, Spain
| | - Yuheng Wang
- School of Ecology and Environment, Northwestern Polytechnical University, Xi'an, China
| | - Peter M Kopittke
- School of Agriculture and Food Sciences, The University of Queensland, St Lucia, Queensland, Australia
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Abstract
Foliar water uptake (FWU) is a mechanism that enables plants to acquire water from the atmosphere through their leaves. As mangroves live in a saline sediment water environment, the mechanism of FWU might be of vital importance to acquire freshwater and grow. The goal of this study was to assess the FWU capacity of six different mangrove species belonging to four genera using a series of submersion experiments in which the leaf mass increase was measured and expressed per unit leaf area. The foliar water uptake capacity differed between species with the highest and lowest average water uptake in Avicennia marina (Forssk.) Vierh. (1.52 ± 0.48 mg H2O cm−2) and Bruguiera gymnorhiza (L.) Lam. (0.13 ± 0.06 mg H2O cm−2), respectively. Salt-excreting species showed a higher FWU capacity than non-excreting species. Moreover, A. marina, a salt-excreting species, showed a distinct leaf anatomical trait, i.e., trichomes, which were not observed in the other species and might be involved in the water absorption process. The storage of leaves in moist Ziplock bags prior to measurement caused leaf water uptake to already occur during transport to the field station, which proportionately increased the leaf water potential (A. marina: −0.31 ± 0.13 MPa and B. gymnorhiza: −2.70 ± 0.27 MPa). This increase should be considered when performing best practice leaf water potential measurements but did not affect the quantification of FWU capacity because of the water potential gradient between a leaf and the surrounding water during submersion. Our results highlight the differences that exist in FWU capacity between species residing in the same area and growing under the same environmental conditions. This comparative study therefore enhances our understanding of mangrove species’ functioning.
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RNAi as a Foliar Spray: Efficiency and Challenges to Field Applications. Int J Mol Sci 2022; 23:ijms23126639. [PMID: 35743077 PMCID: PMC9224206 DOI: 10.3390/ijms23126639] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 06/10/2022] [Accepted: 06/13/2022] [Indexed: 02/04/2023] Open
Abstract
RNA interference (RNAi) is a powerful tool that is being increasingly utilized for crop protection against viruses, fungal pathogens, and insect pests. The non-transgenic approach of spray-induced gene silencing (SIGS), which relies on spray application of double-stranded RNA (dsRNA) to induce RNAi, has come to prominence due to its safety and environmental benefits in addition to its wide host range and high target specificity. However, along with promising results in recent studies, several factors limiting SIGS RNAi efficiency have been recognized in insects and plants. While sprayed dsRNA on the plant surface can produce a robust RNAi response in some chewing insects, plant uptake and systemic movement of dsRNA is required for delivery to many other target organisms. For example, pests such as sucking insects require the presence of dsRNA in vascular tissues, while many fungal pathogens are predominately located in internal plant tissues. Investigating the mechanisms by which sprayed dsRNA enters and moves through plant tissues and understanding the barriers that may hinder this process are essential for developing efficient ways to deliver dsRNA into plant systems. In this review, we assess current knowledge of the plant foliar and cellular uptake of dsRNA molecules. We will also identify major barriers to uptake, including leaf morphological features as well as environmental factors, and address methods to overcome these barriers.
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13
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Chin ARO, Guzmán‐Delgado P, Sillett SC, Orozco J, Kramer RD, Kerhoulas LP, Moore ZJ, Reed M, Zwieniecki MA. Shoot dimorphism enables Sequoia sempervirens to separate requirements for foliar water uptake and photosynthesis. AMERICAN JOURNAL OF BOTANY 2022; 109:564-579. [PMID: 35274309 PMCID: PMC9322557 DOI: 10.1002/ajb2.1841] [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: 01/05/2022] [Revised: 03/04/2022] [Accepted: 03/04/2022] [Indexed: 05/11/2023]
Abstract
PREMISE Trees in wet forests often have features that prevent water films from covering stomata and inhibiting gas exchange, while many trees in drier environments use foliar water uptake to reduce water stress. In forests with both wet and dry seasons, evergreen trees would benefit from producing leaves capable of balancing rainy-season photosynthesis with summertime water absorption. METHODS Using samples collected from across the vertical gradient in tall redwood (Sequoia sempervirens) crowns, we estimated tree-level foliar water uptake and employed physics-based causative modeling to identify key functional traits that determine uptake potential by setting hydraulic resistance. RESULTS We showed that Sequoia has two functionally distinct shoot morphotypes. While most shoots specialize in photosynthesis, the axial shoot type is capable of much greater foliar water uptake, and its within-crown distribution varies with latitude. A suite of leaf surface traits cause hydraulic resistance, leading to variation in uptake capacity among samples. CONCLUSIONS Shoot dimorphism gives tall Sequoia trees the capacity to absorb up to 48 kg H2 O h-1 during the first hour of leaf wetting, ameliorating water stress while presumably maintaining high photosynthetic capacity year round. Geographic variation in shoot dimorphism suggests that plasticity in shoot-type distribution and leaf surface traits helps Sequoia maintain a dominate presence in both wet and dry forests.
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Affiliation(s)
- Alana R. O. Chin
- Plant Sciences DepartmentUniversity of California DavisDavisCA95616USA
- Present address:
Alana R. O. Chin, D‐USYS, ETHZürich8092Switzerland
| | | | - Stephen C. Sillett
- Department of Forestry and Wildland ResourcesHumboldt State UniversityArcataCA95521USA
| | - Jessica Orozco
- Plant Sciences DepartmentUniversity of California DavisDavisCA95616USA
| | | | - Lucy P. Kerhoulas
- Department of Forestry and Wildland ResourcesHumboldt State UniversityArcataCA95521USA
| | - Zane J. Moore
- Plant Sciences DepartmentUniversity of California DavisDavisCA95616USA
| | - Marty Reed
- Department of Biological SciencesHumboldt State UniversityArcataCA95521USA
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Tomasella M, Natale S, Petruzzellis F, Di Bert S, D’Amico L, Tromba G, Nardini A. No Evidence for Light-Induced Embolism Repair in Cut Stems of Drought-Resistant Mediterranean Species under Soaking. PLANTS 2022; 11:plants11030307. [PMID: 35161287 PMCID: PMC8840644 DOI: 10.3390/plants11030307] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 01/17/2022] [Accepted: 01/21/2022] [Indexed: 11/16/2022]
Abstract
(1) Recent studies suggested that stem photosynthesis could favor bark water uptake and embolism recovery when stem segments are soaked in water under light conditions, but evidence for this phenomenon in drought-resistant Mediterranean species with photosynthetic stems is missing. (2) Embolism recovery upon immersion in water for 2 h–4 h under light was assessed (i) via a classical hydraulic method in leafless Fraxinus ornus and Olea europaea branch segments stressed to xylem water potentials (Yxyl) inducing ca. 50% loss of hydraulic conductivity (PLC) and (ii) via X-ray micro-CT imaging of the stem segments of drought-stressed potted F. ornus saplings. Hydraulic recovery was also assessed in vivo in intact drought-stressed F. ornus saplings upon soil re-irrigation. (3) Intact F. ornus plants recovered hydraulic function through root water uptake. Conversely, the soaked stem segments of both species did not refill embolized conduits, although Yxyl recovered to pre-stress levels (between −0.5 MPa and −0.2 MPa). (4) We hypothesize that xylem embolism recovery through bark water uptake, even in light conditions, may not be a common phenomenon in woody plants and/or that wounds caused by cutting short stem segments might inhibit the refilling process upon soaking.
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Affiliation(s)
- Martina Tomasella
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127 Trieste, Italy; (M.T.); (S.N.); (F.P.); (S.D.B.)
| | - Sara Natale
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127 Trieste, Italy; (M.T.); (S.N.); (F.P.); (S.D.B.)
| | - Francesco Petruzzellis
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127 Trieste, Italy; (M.T.); (S.N.); (F.P.); (S.D.B.)
- Dipartimento di Scienze Agroalimentari, Ambientali e Animali, Università di Udine, Via delle Scienze 91, 33100 Udine, Italy
| | - Sara Di Bert
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127 Trieste, Italy; (M.T.); (S.N.); (F.P.); (S.D.B.)
| | - Lorenzo D’Amico
- Elettra-Sincrotrone Trieste, Area Science Park, 34149 Basovizza, Italy (G.T.)
- Dipartimento di Fisica, Università di Trieste, Via A. Valerio 2, 34127 Trieste, Italy
| | - Giuliana Tromba
- Elettra-Sincrotrone Trieste, Area Science Park, 34149 Basovizza, Italy (G.T.)
| | - Andrea Nardini
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127 Trieste, Italy; (M.T.); (S.N.); (F.P.); (S.D.B.)
- Correspondence:
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15
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Bryant C, Fuenzalida TI, Zavafer A, Nguyen HT, Brothers N, Harris RJ, Beckett HAA, Holmlund HI, Binks O, Ball MC. Foliar water uptake via cork warts in mangroves of the Sonneratia genus. PLANT, CELL & ENVIRONMENT 2021; 44:2925-2937. [PMID: 34118083 DOI: 10.1111/pce.14129] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Revised: 06/07/2021] [Accepted: 06/09/2021] [Indexed: 06/12/2023]
Abstract
Foliar water uptake (FWU) occurs in plants of diverse ecosystems; however, the diversity of pathways and their associated FWU kinetics remain poorly resolved. We characterized a novel FWU pathway in two mangrove species of the Sonneratia genus, S. alba and S. caseolaris. Further, we assessed the influence of leaf wetting duration, wet-dry seasonality and leaf dehydration on leaf conductance to surface water (Ksurf ). The symplastic tracer dye, disodium fluorescein, revealed living cells subtending and encircling leaf epidermal structures known as cork warts as a pathway of FWU entry into the leaf. Rehydration kinetics experiments revealed a novel mode of FWU, with slow and steady rates of water uptake persistent over a duration of 12 hr. Ksurf increased with longer durations of leaf wetting and was greater in leaves with more negative water potentials at the initiation of leaf wetting. Ksurf declined by 68% between wet and dry seasons. Our results suggest that FWU via cork warts in Sonneratia sp. may be rate limited and under active regulation. We conclude that FWU pathways in halophytes may require ion exclusion to avoid uptake of salt when inundated, paralleling the capacity of halophyte roots for ion selectivity during water acquisition.
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Affiliation(s)
- Callum Bryant
- Plant Science Division, Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - Tomas I Fuenzalida
- Plant Science Division, Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - Alonso Zavafer
- Plant Science Division, Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - Hoa T Nguyen
- Plant Science Division, Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
- Vietnam National University of Agriculture, Trau Quy, Gia Lam, Ha Noi, Vietnam
| | - Nigel Brothers
- Plant Science Division, Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - Rosalie J Harris
- Plant Science Division, Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - Holly A A Beckett
- Plant Science Division, Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - Helen I Holmlund
- Plant Science Division, Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
- Pepperdine University, Natural Science Division, Malibu, CA, 90263, USA
| | - Oliver Binks
- Plant Science Division, Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - Marilyn C Ball
- Plant Science Division, Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
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