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Sutka MR, Manzur ME, Vitali VA, Micheletto S, Amodeo G. Evidence for the involvement of hydraulic root or shoot adjustments as mechanisms underlying water deficit tolerance in two Sorghum bicolor genotypes. JOURNAL OF PLANT PHYSIOLOGY 2016; 192:13-20. [PMID: 26803215 DOI: 10.1016/j.jplph.2016.01.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 01/06/2016] [Accepted: 01/06/2016] [Indexed: 05/26/2023]
Abstract
Sorghum bicolor (L.) Moench is an ancient drought-tolerant crop with potential to sustain high yields even in those environments where water is limiting. Understanding the performance of this species in early phenological stages could be a useful tool for future yield improvement programs. The aim of this work was to study the response of Sorghum seedlings under water deficit conditions in two genotypes (RedLandB2 and IS9530) that are currently employed in Argentina. Morphological and physiological traits were studied to present an integrated analysis of the shoot and root responses. Although both genotypes initially developed a conserved and indistinguishable response in terms of drought tolerance parameters (growth rate, biomass reallocation, etc.), water regulation displayed different underlying strategies. To avoid water loss, both genotypes adjusted their plant hydraulic resistance at different levels: RedLandB2 regulated shoot resistance through stomata (isohydric strategy), while IS9530 controlled root resistance (anisohydric strategy). Moreover, only in IS9530 was root hydraulic conductance restricted in the presence of HgCl2, in agreement with water movement through cell-to-cell pathways and aquaporins activity. The different responses between genotypes suggest a distinct strategy at the seedling stage and add new information that should be considered when evaluating Sorghum phenotypic plasticity in changing environments.
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Affiliation(s)
- Moira R Sutka
- Departamento de Biodiversidad y Biología Experimental e Instituto de Biodiversidad y Biología Experimental y Aplicada (IBBEA, CONICET-UBA), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Pabellón II, (C1428EGA) Buenos Aires, Argentina
| | - Milena E Manzur
- Departamento de Biodiversidad y Biología Experimental e Instituto de Biodiversidad y Biología Experimental y Aplicada (IBBEA, CONICET-UBA), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Pabellón II, (C1428EGA) Buenos Aires, Argentina
| | - Victoria A Vitali
- Departamento de Biodiversidad y Biología Experimental e Instituto de Biodiversidad y Biología Experimental y Aplicada (IBBEA, CONICET-UBA), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Pabellón II, (C1428EGA) Buenos Aires, Argentina
| | - Sandra Micheletto
- CERZOS-CONICET, Camino La Carrindanga Km 7, (8000) Bahía Blanca, Argentina
| | - Gabriela Amodeo
- Departamento de Biodiversidad y Biología Experimental e Instituto de Biodiversidad y Biología Experimental y Aplicada (IBBEA, CONICET-UBA), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Pabellón II, (C1428EGA) Buenos Aires, Argentina.
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202
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Novick KA, Miniat CF, Vose JM. Drought limitations to leaf-level gas exchange: results from a model linking stomatal optimization and cohesion-tension theory. PLANT, CELL & ENVIRONMENT 2016; 39:583-96. [PMID: 26466749 DOI: 10.1111/pce.12657] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2014] [Accepted: 09/14/2015] [Indexed: 05/23/2023]
Abstract
We merge concepts from stomatal optimization theory and cohesion-tension theory to examine the dynamics of three mechanisms that are potentially limiting to leaf-level gas exchange in trees during drought: (1) a 'demand limitation' driven by an assumption of optimal stomatal functioning; (2) 'hydraulic limitation' of water movement from the roots to the leaves; and (3) 'non-stomatal' limitations imposed by declining leaf water status within the leaf. Model results suggest that species-specific 'economics' of stomatal behaviour may play an important role in differentiating species along the continuum of isohydric to anisohydric behaviour; specifically, we show that non-stomatal and demand limitations may reduce stomatal conductance and increase leaf water potential, promoting wide safety margins characteristic of isohydric species. We used model results to develop a diagnostic framework to identify the most likely limiting mechanism to stomatal functioning during drought and showed that many of those features were commonly observed in field observations of tree water use dynamics. Direct comparisons of modelled and measured stomatal conductance further indicated that non-stomatal and demand limitations reproduced observed patterns of tree water use well for an isohydric species but that a hydraulic limitation likely applies in the case of an anisohydric species.
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Affiliation(s)
- Kimberly A Novick
- School of Public and Environmental Affairs, Indiana University, Bloomington, IN, 47405, USA
| | - Chelcy F Miniat
- USDA Forest Service, Coweeta Hydrologic Laboratory, Otto, NC, 28734, USA
| | - James M Vose
- USDA Forest Service - Southern Research Station - Center for Integrated Forest Science. North Carolina State University, Department of Forestry and Environmental Resources, Raleigh, NC, 27695-8008, USA
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203
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Atkin O. New Phytologist: bridging the 'plant function - climate modelling divide'. THE NEW PHYTOLOGIST 2016; 209:1329-1332. [PMID: 26840246 DOI: 10.1111/nph.13876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
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204
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Plichta R, Urban J, Gebauer R, Dvořák M, Ďurkovič J. Long-term impact of Ophiostoma novo-ulmi on leaf traits and transpiration of branches in the Dutch elm hybrid 'Dodoens'. TREE PHYSIOLOGY 2016; 36:335-44. [PMID: 26843210 PMCID: PMC4885949 DOI: 10.1093/treephys/tpv144] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 12/21/2015] [Indexed: 05/07/2023]
Abstract
To better understand the long-term impact of Ophiostoma novo-ulmi Brasier on leaf physiology in 'Dodoens', a Dutch elm disease-tolerant hybrid, measurements of leaf area, leaf dry mass, petiole anatomy, petiole hydraulic conductivity, leaf and branch water potential, and branch sap flow were performed 3 years following an initial artificial inoculation. Although fungal hyphae were detected in fully expanded leaves, neither anatomical nor morphological traits were affected, indicating that there was no impact from the fungal hyphae on the leaves during leaf expansion. In contrast, however, infected trees showed both a lower transpiration rate of branches and a lower sap flow density. The long-term persistence of fungal hyphae inside vessels decreased the xylem hydraulic conductivity, but stomatal regulation of transpiration appeared to be unaffected as the leaf water potential in both infected and non-infected trees was similarly driven by the transpirational demands. Regardless of the fungal infection, leaves with a higher leaf mass per area ratio tended to have a higher leaf area-specific conductivity. Smaller leaves had an increased number of conduits with smaller diameters and thicker cell walls. Such a pattern could increase tolerance towards hydraulic dysfunction. Measurements of water potential and theoretical xylem conductivity revealed that petiole anatomy could predict the maximal transpiration rate. Three years following fungal inoculation, phenotypic expressions for the majority of the examined traits revealed a constitutive nature for their possible role in Dutch elm disease tolerance of 'Dodoens' trees.
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Affiliation(s)
- Roman Plichta
- Department of Forest Botany, Dendrology and Geobiocoenology, Mendel University in Brno, Zemědělská 3, 61300 Brno, Czech Republic
| | - Josef Urban
- Department of Forest Botany, Dendrology and Geobiocoenology, Mendel University in Brno, Zemědělská 3, 61300 Brno, Czech Republic
| | - Roman Gebauer
- Department of Forest Botany, Dendrology and Geobiocoenology, Mendel University in Brno, Zemědělská 3, 61300 Brno, Czech Republic
| | - Miloň Dvořák
- Department of Forest Protection and Wildlife Management, Mendel University in Brno, Zemědělská 3, 61300 Brno, Czech Republic
| | - Jaroslav Ďurkovič
- Department of Phytology, Technical University in Zvolen, T. G. Masaryka 24, 960 53 Zvolen, Slovak Republic
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205
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Rosner S, Světlík J, Andreassen K, Børja I, Dalsgaard L, Evans R, Luss S, Tveito OE, Solberg S. Novel Hydraulic Vulnerability Proxies for a Boreal Conifer Species Reveal That Opportunists May Have Lower Survival Prospects under Extreme Climatic Events. FRONTIERS IN PLANT SCIENCE 2016; 7:831. [PMID: 27375672 PMCID: PMC4899478 DOI: 10.3389/fpls.2016.00831] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 05/26/2016] [Indexed: 05/07/2023]
Abstract
Top dieback in 40-60 years old forest stands of Norway spruce [Picea abies (L.) Karst.] in southern Norway is supposed to be associated with climatic extremes. Our intention was to learn more about the processes related to top dieback and in particular about the plasticity of possible predisposing factors. We aimed at (i) developing proxies for P 50 based on anatomical data assessed by SilviScan technology and (ii) testing these proxies for their plasticity regarding climate, in order to (iii) analyze annual variations of hydraulic proxies of healthy looking trees and trees with top dieback upon their impact on tree survival. At two sites we selected 10 tree pairs, i.e., one healthy looking tree and one tree with visual signs of dieback such as dry tops, needle shortening and needle yellowing (n = 40 trees). Vulnerability to cavitation (P 50) of the main trunk was assessed in a selected sample set (n = 19) and we thereafter applied SilviScan technology to measure cell dimensions (lumen (b) and cell wall thickness (t)) in these specimen and in all 40 trees in tree rings formed between 1990 and 2010. In a first analysis step, we searched for anatomical proxies for P 50. The set of potential proxies included hydraulic lumen diameters and wall reinforcement parameters based on mean, radial, and tangential tracheid diameters. The conduit wall reinforcement based on tangential hydraulic lumen diameters ((t/b ht)(2)) was the best estimate for P 50. It was thus possible to relate climatic extremes to the potential vulnerability of single annual rings. Trees with top dieback had significantly lower (t/b ht)(2) and wider tangential (hydraulic) lumen diameters some years before a period of water deficit (2005-2006). Radial (hydraulic) lumen diameters showed however no significant differences between both tree groups. (t/b ht)(2) was influenced by annual climate variability; strongest correlations were found with precipitation in September of the previous growing season: high precipitation in previous September resulted in more vulnerable annual rings in the next season. The results are discussed with respect to an "opportunistic behavior" and genetic predisposition to drought sensitivity.
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Affiliation(s)
- Sabine Rosner
- Institute of Botany, BOKU ViennaVienna, Austria
- *Correspondence: Sabine Rosner
| | - Jan Světlík
- Centre MendelGlobe – Global Climate Change and Managed Ecosystems, Mendel UniversityBrno, Czech Republic
| | | | | | | | - Robert Evans
- CSIRO Materials Science and EngineeringClayton, VIC, Australia
| | - Saskia Luss
- Institute of Botany, BOKU ViennaVienna, Austria
| | | | - Svein Solberg
- Norwegian Institute of Bioeconomy ResearchÅs, Norway
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206
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Garcia-Forner N, Adams HD, Sevanto S, Collins AD, Dickman LT, Hudson PJ, Zeppel MJB, Jenkins MW, Powers H, Martínez-Vilalta J, Mcdowell NG. Responses of two semiarid conifer tree species to reduced precipitation and warming reveal new perspectives for stomatal regulation. PLANT, CELL & ENVIRONMENT 2016; 39:38-49. [PMID: 26081870 DOI: 10.1111/pce.12588] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Revised: 05/29/2015] [Accepted: 06/01/2015] [Indexed: 05/13/2023]
Abstract
Relatively anisohydric species are predicted to be more predisposed to hydraulic failure than relatively isohydric species, as they operate with narrower hydraulic safety margins. We subjected co-occurring anisohydric Juniperus monosperma and isohydric Pinus edulis trees to warming, reduced precipitation, or both, and measured their gas exchange and hydraulic responses. We found that reductions in stomatal conductance and assimilation by heat and drought were more frequent during relatively moist periods, but these effects were not exacerbated in the combined heat and drought treatment. Counter to expectations, both species exhibited similar gs temporal dynamics in response to drought. Further, whereas P. edulis exhibited chronic embolism, J. monosperma showed very little embolism due to its conservative stomatal regulation and maintenance of xylem water potential above the embolism entry point. This tight stomatal control and low levels of embolism experienced by juniper refuted the notion that very low water potentials during drought are associated with loose stomatal control and with the hypothesis that anisohydric species are more prone to hydraulic failure than isohydric species. Because direct association of stomatal behaviour with embolism resistance can be misleading, we advocate consideration of stomatal behaviour relative to embolism resistance for classifying species drought response strategies.
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Affiliation(s)
- Núria Garcia-Forner
- CREAF, Cerdanyola del Vallès, 08193, Spain
- Universitat Autònoma Barcelona, Cerdanyola del Vallès, 08193, Spain
| | - Henry D Adams
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Sanna Sevanto
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Adam D Collins
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Lee T Dickman
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Patrick J Hudson
- Department of Biology, University of New Mexico, Albuquerque, NM, 87131, USA
| | - Melanie J B Zeppel
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales, 2109, Australia
| | - Michael W Jenkins
- Department of Environmental Studies, University of California, Santa Cruz, California, 95064, USA
| | - Heath Powers
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Jordi Martínez-Vilalta
- CREAF, Cerdanyola del Vallès, 08193, Spain
- Universitat Autònoma Barcelona, Cerdanyola del Vallès, 08193, Spain
| | - Nate G Mcdowell
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
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207
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Mencuccini M, Minunno F, Salmon Y, Martínez-Vilalta J, Hölttä T. Coordination of physiological traits involved in drought-induced mortality of woody plants. THE NEW PHYTOLOGIST 2015; 208:396-409. [PMID: 25988920 DOI: 10.1111/nph.13461] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Accepted: 04/11/2015] [Indexed: 06/04/2023]
Abstract
Accurate modelling of drought-induced mortality is challenging. A steady-state model is presented integrating xylem and phloem transport, leaf-level gas exchange and plant carbohydrate consumption during drought development. A Bayesian analysis of parameter uncertainty based on expert knowledge and a literature review is carried out. The model is tested by combining six data compilations covering 170 species using information on sensitivities of xylem conductivity, stomatal conductance and leaf turgor to water potential. The possible modes of plant failure at steady state are identified (i.e. carbon (C) starvation, hydraulic failure and phloem transport failure). Carbon starvation occurs primarily in the parameter space of isohydric stomatal control, whereas hydraulic failure is prevalent in the space of xylem susceptibility to embolism. Relative to C starvation, phloem transport failure occurs under conditions of low sensitivity of photosynthesis and high sensitivity of growth to plant water status. These three failure modes are possible extremes along two axes of physiological vulnerabilities, one characterized by the balance of water supply and demand and the other by the balance between carbohydrate sources and sinks. Because the expression of physiological vulnerabilities is coordinated, we argue that different failure modes should occur with roughly equal likelihood, consistent with predictions using optimality theory.
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Affiliation(s)
- Maurizio Mencuccini
- School of GeoSciences, University of Edinburgh, Edinburgh, EH9 3FF, UK
- ICREA at CREAF, Cerdanyola del Vallès, Barcelona, 08193, Spain
| | - Francesco Minunno
- Department of Forest Science, University of Helsinki, PO Box 27, Helsinki, FI-00014, Finland
| | - Yann Salmon
- School of GeoSciences, University of Edinburgh, Edinburgh, EH9 3FF, UK
| | - Jordi Martínez-Vilalta
- CREAF, Cerdanyola del Vallès, Barcelona, 08193, Spain
- University of Autònoma Barcelona, Cerdanyola del Vallès, Barcelona, 08193, Spain
| | - Teemu Hölttä
- Department of Forest Science, University of Helsinki, PO Box 27, Helsinki, FI-00014, Finland
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208
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Cardoso JA, Pineda M, Jiménez JDLC, Vergara MF, Rao IM. Contrasting strategies to cope with drought conditions by two tropical forage C4 grasses. AOB PLANTS 2015; 7:plv107. [PMID: 26333827 PMCID: PMC4595746 DOI: 10.1093/aobpla/plv107] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 08/26/2015] [Indexed: 05/16/2023]
Abstract
Drought severely limits forage productivity of C4 grasses across the tropics. The avoidance of water deficit by increasing the capacity for water uptake or by controlling water loss are common responses in forage C4 grasses. Napier grass (Pennisetum purpureum) and Brachiaria hybrid cv. Mulato II are tropical C4 grasses used for livestock production due to their reputed resistance to drought conditions. However, there is scant information on the mechanisms used by these grasses to overcome water-limited conditions. Therefore, assessments of cumulative transpired water, shoot growth, leaf rolling, leaf gas exchange, dry mass production and a number of morpho-physiological traits were recorded over a period of 21 days under well-watered or drought conditions. Drought reduced shoot dry mass of both grasses by 35 %, yet each grass exhibited contrasting strategies to cope with water shortage. Napier grass transpired most available water by the end of the drought treatment, whereas a significant amount of water was still available for Mulato II. Napier grass maintained carbon assimilation until the soil was fairly dry, whereas Mulato II restricted water loss by early stomatal closure at relatively wet soil conditions. Our results suggest that Napier grass exhibits a 'water-spending' behaviour that might be targeted to areas with intermittent drought stress, whereas Mulato II displays a 'water-saving' nature that could be directed to areas with longer dry periods.
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Affiliation(s)
- Juan Andrés Cardoso
- Tropical Forages Program, International Center for Tropical Agriculture (CIAT), Apartado Aéreo 6713, Cali, Colombia
| | - Marcela Pineda
- Tropical Forages Program, International Center for Tropical Agriculture (CIAT), Apartado Aéreo 6713, Cali, Colombia Facultad de Ciencias Agrarias, Universidad Nacional de Colombia, Carrera 30 No. 45-03, Bogotá, Colombia
| | - Juan de la Cruz Jiménez
- Tropical Forages Program, International Center for Tropical Agriculture (CIAT), Apartado Aéreo 6713, Cali, Colombia
| | - Manuel Fernando Vergara
- Facultad de Ciencias Agrarias, Universidad Nacional de Colombia, Carrera 30 No. 45-03, Bogotá, Colombia
| | - Idupulapati M Rao
- Tropical Forages Program, International Center for Tropical Agriculture (CIAT), Apartado Aéreo 6713, Cali, Colombia
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209
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Comparative Drought Responses of Quercus ilex L. and Pinus sylvestris L. in a Montane Forest Undergoing a Vegetation Shift. FORESTS 2015. [DOI: 10.3390/f6082505] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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210
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Sperry JS, Love DM. What plant hydraulics can tell us about responses to climate-change droughts. THE NEW PHYTOLOGIST 2015; 207:14-27. [PMID: 25773898 DOI: 10.1111/nph.13354] [Citation(s) in RCA: 175] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 01/30/2015] [Indexed: 05/02/2023]
Abstract
Climate change exposes vegetation to unusual drought, causing declines in productivity and increased mortality. Drought responses are hard to anticipate because canopy transpiration and diffusive conductance (G) respond to drying soil and vapor pressure deficit (D) in complex ways. A growing database of hydraulic traits, combined with a parsimonious theory of tree water transport and its regulation, may improve predictions of at-risk vegetation. The theory uses the physics of flow through soil and xylem to quantify how canopy water supply declines with drought and ceases by hydraulic failure. This transpiration 'supply function' is used to predict a water 'loss function' by assuming that stomatal regulation exploits transport capacity while avoiding failure. Supply-loss theory incorporates root distribution, hydraulic redistribution, cavitation vulnerability, and cavitation reversal. The theory efficiently defines stomatal responses to D, drying soil, and hydraulic vulnerability. Driving the theory with climate predicts drought-induced loss of plant hydraulic conductance (k), canopy G, carbon assimilation, and productivity. Data lead to the 'chronic stress hypothesis' wherein > 60% loss of k increases mortality by multiple mechanisms. Supply-loss theory predicts the climatic conditions that push vegetation over this risk threshold. The theory's simplicity and predictive power encourage testing and application in large-scale modeling.
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Affiliation(s)
- John S Sperry
- Department of Biology, University of Utah, Salt Lake City, UT, 84112, USA
| | - David M Love
- Department of Biology, University of Utah, Salt Lake City, UT, 84112, USA
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211
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Attia Z, Domec JC, Oren R, Way DA, Moshelion M. Growth and physiological responses of isohydric and anisohydric poplars to drought. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:4373-81. [PMID: 25954045 PMCID: PMC4493787 DOI: 10.1093/jxb/erv195] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Understanding how different plants prioritize carbon gain and drought vulnerability under a variable water supply is important for predicting which trees will maximize woody biomass production under different environmental conditions. Here, Populus balsamifera (BS, isohydric genotype), P. simonii (SI, previously uncharacterized stomatal behaviour), and their cross, P. balsamifera x simonii (BSxSI, anisohydric genotype) were studied to assess the physiological basis for biomass accumulation and water-use efficiency across a range of water availabilities. Under ample water, whole plant stomatal conductance (gs), transpiration (E), and growth rates were higher in anisohydric genotypes (SI and BSxSI) than in isohydric poplars (BS). Under drought, all genotypes regulated the leaf to stem water potential gradient via changes in gs, synchronizing leaf hydraulic conductance (Kleaf) and E: isohydric plants reduced Kleaf, gs, and E, whereas anisohydric genotypes maintained high Kleaf and E, which reduced both leaf and stem water potentials. Nevertheless, SI poplars reduced their plant hydraulic conductance (Kplant) during water stress and, unlike, BSxSI plants, recovered rapidly from drought. Low gs of the isohydric BS under drought reduced CO2 assimilation rates and biomass potential under moderate water stress. While anisohydric genotypes had the fastest growth under ample water and higher photosynthetic rates under increasing water stress, isohydric poplars had higher water-use efficiency. Overall, the results indicate three strategies for how closely related biomass species deal with water stress: survival-isohydric (BS), sensitive-anisohydric (BSxSI), and resilience-anisohydric (SI). Implications for woody biomass growth, water-use efficiency, and survival under variable environmental conditions are discussed.
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Affiliation(s)
- Ziv Attia
- Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel
| | - Jean-Christophe Domec
- Bordeaux Sciences Agro UMR INRA-ISPA 1391, 33195, Gradignan, France Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, NC 27695, USA Nicholas School of the Environment and Earth Sciences, Duke University, Durham, North Carolina 27708, USA
| | - Ram Oren
- Nicholas School of the Environment and Earth Sciences, Duke University, Durham, North Carolina 27708, USA Department of Forest Ecology & Management, Swedish University of Agricultural Sciences (SLU), SE-901 83, Umeå, Sweden
| | - Danielle A Way
- Nicholas School of the Environment and Earth Sciences, Duke University, Durham, North Carolina 27708, USA Department of Biology, University of Western Ontario, London, ON, N6A 5B7, Canada
| | - Menachem Moshelion
- Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel
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212
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Roman DT, Novick KA, Brzostek ER, Dragoni D, Rahman F, Phillips RP. The role of isohydric and anisohydric species in determining ecosystem-scale response to severe drought. Oecologia 2015; 179:641-54. [PMID: 26130023 DOI: 10.1007/s00442-015-3380-9] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 06/16/2015] [Indexed: 11/25/2022]
Abstract
Ongoing shifts in the species composition of Eastern US forests necessitate the development of frameworks to explore how species-specific water-use strategies influence ecosystem-scale carbon (C) cycling during drought. Here, we develop a diagnostic framework to classify plant drought-response strategies along a continuum of isohydric to anisohydric regulation of leaf water potential (Ψ(L)). The framework is applied to a 3-year record of weekly leaf-level gas exchange and Ψ measurements collected in the Morgan-Monroe State Forest (Indiana, USA), where continuous observations of the net ecosystem exchange of CO2 (NEE) have been ongoing since 1999. A severe drought that occurred in the middle of the study period reduced the absolute magnitude of NEE by 55%, though species-specific responses to drought conditions varied. Oak species were characterized by anisohydric regulation of Ψ(L) that promoted static gas exchange throughout the study period. In contrast, Ψ(L) of the other canopy dominant species was more isohydric, which limited gas exchange during the drought. Ecosystem-scale estimates of NEE and gross ecosystem productivity derived by upscaling the leaf-level data agreed well with tower-based observations, and highlight how the fraction of isohydric and anisohydric species in forests can mediate net ecosystem C balance.
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Affiliation(s)
- D T Roman
- School of Public and Environmental Affairs, Indiana University-Bloomington, 702 North Walnut Grove Avenue, Bloomington, IN, 47405, USA
| | - K A Novick
- School of Public and Environmental Affairs, Indiana University-Bloomington, 702 North Walnut Grove Avenue, Bloomington, IN, 47405, USA.
| | - E R Brzostek
- Department of Biology, West Virginia University, 53 Campus Drive, Morgantown, WV, 26505, USA
| | - D Dragoni
- Department of Geography, Indiana University-Bloomington, 702 North Walnut Grove Avenue, Bloomington, IN, 47405, USA
| | - F Rahman
- Department of Biology, The University of Texas Rio Grande Valley, 1201 West University Drive, Edinburg, TX, 78539, USA
| | - R P Phillips
- Department of Biology, Indiana University-Bloomington, 1001 East Third Street, Bloomington, IN, 47405, USA
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213
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McCulloh KA, Meinzer FC. Further evidence that some plants can lose and regain hydraulic function daily. TREE PHYSIOLOGY 2015; 35:691-3. [PMID: 26163489 DOI: 10.1093/treephys/tpv066] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 06/18/2015] [Indexed: 05/02/2023]
Affiliation(s)
| | - Frederick C Meinzer
- USDA Forest Service, Pacific Northwest Research Station, Corvallis, OR 97331, USA
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214
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Renninger HJ, Carlo NJ, Clark KL, Schäfer KVR. Resource use and efficiency, and stomatal responses to environmental drivers of oak and pine species in an Atlantic Coastal Plain forest. FRONTIERS IN PLANT SCIENCE 2015; 6:297. [PMID: 25999966 PMCID: PMC4423344 DOI: 10.3389/fpls.2015.00297] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 04/13/2015] [Indexed: 05/30/2023]
Abstract
Pine-oak ecosystems are globally distributed even though differences in anatomy and leaf habit between many co-occurring oaks and pines suggest different strategies for resource use, efficiency and stomatal behavior. The New Jersey Pinelands contain sandy soils with low water- and nutrient-holding capacity providing an opportunity to examine trade-offs in resource uptake and efficiency. Therefore, we compared resource use in terms of transpiration rates and leaf nitrogen content and resource-use efficiency including water-use efficiency (WUE) via gas exchange and leaf carbon isotopes and photosynthetic nitrogen-use efficiency (PNUE) between oaks (Quercus alba, Q. prinus, Q. velutina) and pines (Pinus rigida, P. echinata). We also determined environmental drivers [vapor pressure deficit (VPD), soil moisture, solar radiation] of canopy stomatal conductance (GS) estimated via sap flow and stomatal sensitivity to light and soil moisture. Net assimilation rates were similar between genera, but oak leaves used about 10% more water and pine foliage contained about 20% more N per unit leaf area. Therefore, oaks exhibited greater PNUE while pines had higher WUE based on gas exchange, although WUE from carbon isotopes was not significantly different. For the environmental drivers of GS, oaks had about 10% lower stomatal sensitivity to VPD normalized by reference stomatal conductance compared with pines. Pines exhibited a significant positive relationship between shallow soil moisture and GS, but only GS in Q. velutina was positively related to soil moisture. In contrast, stomatal sensitivity to VPD was significantly related to solar radiation in all oak species but only pines at one site. Therefore, oaks rely more heavily on groundwater resources but have lower WUE, while pines have larger leaf areas and nitrogen acquisition but lower PNUE demonstrating a trade-off between using water and nitrogen efficiently in a resource-limited ecosystem.
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Affiliation(s)
- Heidi J. Renninger
- Department of Biological Sciences, Rutgers, The State University of New JerseyNewark, NJ, USA
| | - Nicholas J. Carlo
- Department of Earth and Environmental Sciences, Rutgers, The State University of New JerseyNewark, NJ, USA
| | - Kenneth L. Clark
- Silas Little Experimental Forest, Northern Research Station, United States Department of Agriculture Forest ServiceNew Lisbon, NJ, USA
| | - Karina V. R. Schäfer
- Department of Biological Sciences, Rutgers, The State University of New JerseyNewark, NJ, USA
- Department of Earth and Environmental Sciences, Rutgers, The State University of New JerseyNewark, NJ, USA
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215
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Xiong W, Oren R, Wang Y, Yu P, Liu H, Cao G, Xu L, Wang Y, Zuo H. Heterogeneity of competition at decameter scale: patches of high canopy leaf area in a shade-intolerant larch stand transpire less yet are more sensitive to drought. TREE PHYSIOLOGY 2015; 35:470-484. [PMID: 25836360 DOI: 10.1093/treephys/tpv022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 02/19/2015] [Indexed: 06/04/2023]
Abstract
Small differences in the sensitivity of stomatal conductance to light intensity on leaf surfaces may lead to large differences in total canopy transpiration (EC) with increasing canopy leaf area (L). Typically, the increase of L would more than compensate for the decrease of transpiration per unit of leaf area (EL), resulting in concurrent increase of EC. However, highly shade-intolerant species, such as Larix principis-rupprechtii Mayr., may be so sensitive to increased shading that such compensation is not complete. We hypothesized that in such a stand, windfall-induced spatial variation at a decameter scale would result in greatly reduced EL in patches of high L leading to lower EC than low competition patches of sparse canopy. We further hypothesized that quicker extraction of soil moisture in patches of lower competition will result in earlier onset of drought symptoms in these patches. Thus, patches of low L will transition from light to soil moisture as the factor dominating EL. This process should progressively homogenize EC in the stand even as the variation of soil moisture is increasing. We tested the hypotheses utilizing sap flux of nine trees, and associated environmental and stand variables. The results were consistent with only some of the expectations. Under non-limiting soil moisture, EL was very sensitive to the spatial variation of L, decreasing sharply with increasing L and associated decrease of mean light intensity on leaf surfaces. Thus, under the conditions of ample soil moisture maximum EC decreased with increasing patch-scale L. Annual EC and biomass production also decreased with L, albeit more weakly. Furthermore, variation of EC among patches decreased as average stand soil moisture declined between rain events. However, contrary to expectation, high L plots which transpired less showed a greater EL sensitivity to decreasing stand-scale soil moisture, suggesting a different mechanism than simple control by decreasing soil moisture. We offer potential explanations to the observed phenomenon. Our results demonstrate that spatial variation of L at decameter scale, even within relatively homogeneous, single-species, even-aged stands, can produce large variation of transpiration, soil moisture and biomass production and should be considered in 1-D soil-plant-atmosphere models.
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Affiliation(s)
- Wei Xiong
- Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing 100091, P.R. China
| | - Ram Oren
- Nicholas School of the Environment and Earth Sciences, Duke University, Durham, NC 27708, USA Department of Forest Ecology and Management, Swedish University of Agricultural Sciences (SLU), SE-901 83 Umeå, Sweden
| | - Yanhui Wang
- Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing 100091, P.R. China
| | - Pengtao Yu
- Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing 100091, P.R. China
| | - Hailong Liu
- Monitoring Station of Environmental Protection Center in Erdos, Bureau of Environmental Protection of Erdos in Inner Mongolia of China, Erdos 017000, P.R. China
| | - Gongxiang Cao
- Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing 100091, P.R. China
| | - Lihong Xu
- Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing 100091, P.R. China
| | - Yunni Wang
- Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing 100091, P.R. China
| | - Haijun Zuo
- Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing 100091, P.R. China
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216
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Tardieu F, Simonneau T, Parent B. Modelling the coordination of the controls of stomatal aperture, transpiration, leaf growth, and abscisic acid: update and extension of the Tardieu-Davies model. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:2227-37. [PMID: 25770586 PMCID: PMC4986722 DOI: 10.1093/jxb/erv039] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Revised: 01/09/2015] [Accepted: 01/14/2015] [Indexed: 05/19/2023]
Abstract
Stomatal aperture, transpiration, leaf growth, hydraulic conductance, and concentration of abscisic acid in the xylem sap ([ABA]xyl) vary rapidly with time of day. They follow deterministic relations with environmental conditions and interact in such a way that a change in any one of them affects all the others. Hence, approaches based on measurements of one variable at a given time or on paired correlations are prone to a confusion of effects, in particular for studying their genetic variability. A dynamic model allows the simulation of environmental effects on the variables, and of multiple feedbacks between them at varying time resolutions. This paper reviews the control of water movement through the plant, stomatal aperture and growth, and translates them into equations in a model. It includes recent progress in understanding the intrinsic and environmental controls of tissue hydraulic conductance as a function of transpiration rate, circadian rhythms, and [ABA]xyl. Measured leaf water potential is considered as the water potential of a capacitance representing mature tissues, which reacts more slowly to environmental cues than xylem water potential and expansive growth. Combined with equations for water and ABA fluxes, it results in a dynamic model able to simulate variables with genotype-specific parameters. It allows adaptive roles for hydraulic processes to be proposed, in particular the circadian oscillation of root hydraulic conductance. The script of the model, in the R language, is included together with appropriate documentation and examples.
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Affiliation(s)
- François Tardieu
- INRA, UMR759 Laboratoire d'Ecophysiologie des Plantes sous Stress Environnementaux, Place Viala, F-34060 Montpellier, France
| | - Thierry Simonneau
- INRA, UMR759 Laboratoire d'Ecophysiologie des Plantes sous Stress Environnementaux, Place Viala, F-34060 Montpellier, France
| | - Boris Parent
- INRA, UMR759 Laboratoire d'Ecophysiologie des Plantes sous Stress Environnementaux, Place Viala, F-34060 Montpellier, France
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217
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Franklin O, Palmroth S, Näsholm T. How eco-evolutionary principles can guide tree breeding and tree biotechnology for enhanced productivity. TREE PHYSIOLOGY 2014; 34:1149-1166. [PMID: 25542897 DOI: 10.1093/treephys/tpu111] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Tree breeding and biotechnology can enhance forest productivity and help alleviate the rising pressure on forests from climate change and human exploitation. While many physiological processes and genes are targeted in search of genetically improved tree productivity, an overarching principle to guide this search is missing. Here, we propose a method to identify the traits that can be modified to enhance productivity, based on the differences between trees shaped by natural selection and 'improved' trees with traits optimized for productivity. We developed a tractable model of plant growth and survival to explore such potential modifications under a range of environmental conditions, from non-water limited to severely drought-limited sites. We show how key traits are controlled by a trade-off between productivity and survival, and that productivity can be increased at the expense of long-term survival by reducing isohydric behavior (stomatal regulation of leaf water potential) and allocation to defense against pests compared with native trees. In contrast, at dry sites occupied by naturally drought-resistant trees, the model suggests a better strategy may be to select trees with slightly lower wood density than the native trees and to augment isohydric behavior and allocation to defense. Thus, which traits to modify, and in which direction, depend on the original tree species or genotype, the growth environment and wood-quality versus volume production preferences. In contrast to this need for customization of drought and pest resistances, consistent large gains in productivity for all genotypes can be obtained if root traits can be altered to reduce competition for water and nutrients. Our approach illustrates the potential of using eco-evolutionary theory and modeling to guide plant breeding and genetic technology in selecting target traits in the quest for higher forest productivity.
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Affiliation(s)
- Oskar Franklin
- Ecosystems Services and Management Program , International Institute for Applied Systems Analysis, A-2361 Laxenburg , Austria;
| | - Sari Palmroth
- Nicholas School of the Environment and Earth Sciences, Duke University, Durham, NC 27708 , USA
| | - Torgny Näsholm
- Department of Forest Ecology and Management , Swedish University of Agricultural Sciences, SE-901 83 Umeå , Sweden; Department of Forest Genetics and Plant Physiology , Umeå Plant Science Centre, Swedish University of Agricultural Sciences, SE-901 85 Umeå , Sweden
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218
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Manzoni S. Integrating plant hydraulics and gas exchange along the drought-response trait spectrum. TREE PHYSIOLOGY 2014; 34:1031-4. [PMID: 25378559 DOI: 10.1093/treephys/tpu088] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Affiliation(s)
- Stefano Manzoni
- Department of Physical Geography and Quaternary Geology, Stockholm University, Svante Arrhenius väg 8C, Frescati, SE-106 91 Stockholm, Sweden
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