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Gauthey A, Kahmen A, Limousin JM, Vilagrosa A, Didion-Gency M, Mas E, Milano A, Tunas A, Grossiord C. High heat tolerance, evaporative cooling, and stomatal decoupling regulate canopy temperature and their safety margins in three European oak species. GLOBAL CHANGE BIOLOGY 2024; 30:e17439. [PMID: 39092538 DOI: 10.1111/gcb.17439] [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: 02/15/2024] [Revised: 06/03/2024] [Accepted: 07/08/2024] [Indexed: 08/04/2024]
Abstract
Heatwaves and soil droughts are increasing in frequency and intensity, leading many tree species to exceed their thermal thresholds, and driving wide-scale forest mortality. Therefore, investigating heat tolerance and canopy temperature regulation mechanisms is essential to understanding and predicting tree vulnerability to hot droughts. We measured the diurnal and seasonal variation in leaf water potential (Ψ), gas exchange (photosynthesis Anet and stomatal conductance gs), canopy temperature (Tcan), and heat tolerance (leaf critical temperature Tcrit and thermal safety margins TSM, i.e., the difference between maximum Tcan and Tcrit) in three oak species in forests along a latitudinal gradient (Quercus petraea in Switzerland, Quercus ilex in France, and Quercus coccifera in Spain) throughout the growing season. Gas exchange and Ψ of all species were strongly reduced by increased air temperature (Tair) and soil drying, resulting in stomatal closure and inhibition of photosynthesis in Q. ilex and Q. coccifera when Tair surpassed 30°C and soil moisture dropped below 14%. Across all seasons, Tcan was mainly above Tair but increased strongly (up to 10°C > Tair) when Anet was null or negative. Although trees endured extreme Tair (up to 42°C), positive TSM were maintained during the growing season due to high Tcrit in all species (average Tcrit of 54.7°C) and possibly stomatal decoupling (i.e., Anet ≤0 while gs >0). Indeed, Q. ilex and Q. coccifera trees maintained low but positive gs (despite null Anet), decreasing Ψ passed embolism thresholds. This may have prevented Tcan from rising above Tcrit during extreme heat. Overall, our work highlighted that the mechanisms behind heat tolerance and leaf temperature regulation in oak trees include a combination of high evaporative cooling, large heat tolerance limits, and stomatal decoupling. These processes must be considered to accurately predict plant damages, survival, and mortality during extreme heatwaves.
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Affiliation(s)
- Alice Gauthey
- Plant Ecology Research Laboratory PERL, School of Architecture, Civil and Environmental Engineering, EPFL, Lausanne, Switzerland
- Community Ecology Unit, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
- Birmingham Institute of Forest Research, University of Birmingham, Birmingham, UK
| | - Ansgar Kahmen
- Physiological Plant Ecology, Department of Environmental Sciences, University of Basel, Basel, Switzerland
| | - Jean-Marc Limousin
- Centre d'Ecologie Fonctionnelle et Evolutive, CNRS, EPHE, IRD, Université de Montpellier, Montpellier, France
| | - Alberto Vilagrosa
- CEAM Foundation, Joint Research Unit University of Alicante-CEAM, Department Ecology, University of Alicante, Alicante, Spain
| | - Margaux Didion-Gency
- Forest Dynamics Unit, Swiss Federal Institute for Forest, Snow and Landscape WSL, Birmensdorf, Switzerland
| | - Eugénie Mas
- Plant Ecology Research Laboratory PERL, School of Architecture, Civil and Environmental Engineering, EPFL, Lausanne, Switzerland
- Community Ecology Unit, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
- Forest Global Earth Observatory, Smithsonian Tropical Research Institute, Washington, District of Columbia, USA
| | - Arianna Milano
- Plant Ecology Research Laboratory PERL, School of Architecture, Civil and Environmental Engineering, EPFL, Lausanne, Switzerland
- Community Ecology Unit, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
| | - Alex Tunas
- Plant Ecology Research Laboratory PERL, School of Architecture, Civil and Environmental Engineering, EPFL, Lausanne, Switzerland
- Community Ecology Unit, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
- Department of Ecology, University of Innsbruck, Innsbruck, Austria
| | - Charlotte Grossiord
- Plant Ecology Research Laboratory PERL, School of Architecture, Civil and Environmental Engineering, EPFL, Lausanne, Switzerland
- Community Ecology Unit, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
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2
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Middleby KB, Cheesman AW, Cernusak LA. Impacts of elevated temperature and vapour pressure deficit on leaf gas exchange and plant growth across six tropical rainforest tree species. THE NEW PHYTOLOGIST 2024; 243:648-661. [PMID: 38757766 DOI: 10.1111/nph.19822] [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: 12/16/2023] [Accepted: 04/30/2024] [Indexed: 05/18/2024]
Abstract
Elevated air temperature (Tair) and vapour pressure deficit (VPDair) significantly influence plant functioning, yet their relative impacts are difficult to disentangle. We examined the effects of elevated Tair (+6°C) and VPDair (+0.7 kPa) on the growth and physiology of six tropical tree species. Saplings were grown under well-watered conditions in climate-controlled glasshouses for 6 months under three treatments: (1) low Tair and low VPDair, (2) high Tair and low VPDair, and (3) high Tair and high VPDair. To assess acclimation, physiological parameters were measured at a set temperature. Warm-grown plants grown under elevated VPDair had significantly reduced stomatal conductance and increased instantaneous water use efficiency compared to plants grown under low VPDair. Photosynthetic biochemistry and thermal tolerance (Tcrit) were unaffected by VPDair, but elevated Tair caused Jmax25 to decrease and Tcrit to increase. Sapling biomass accumulation for all species responded positively to an increase in Tair, but elevated VPDair limited growth. This study shows that stomatal limitation caused by even moderate increases in VPDair can decrease productivity and growth rates in tropical species independently from Tair and has important implications for modelling the impacts of climate change on tropical forests.
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Affiliation(s)
- Kali B Middleby
- College of Science and Engineering, James Cook University, Cairns, QLD, 4878, Australia
| | - Alexander W Cheesman
- College of Science and Engineering, James Cook University, Cairns, QLD, 4878, Australia
| | - Lucas A Cernusak
- College of Science and Engineering, James Cook University, Cairns, QLD, 4878, Australia
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3
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Teng Z, Chen C, He Y, Pan S, Liu D, Zhu L, Liang K, Li Y, Huang L. Melatonin confers thermotolerance and antioxidant capacity in Chinese cabbage. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2024; 212:108736. [PMID: 38797006 DOI: 10.1016/j.plaphy.2024.108736] [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: 09/26/2023] [Revised: 05/15/2024] [Accepted: 05/15/2024] [Indexed: 05/29/2024]
Abstract
Due to the damaging effect of high temperatures on plant development, global warming is predicted to increase agricultural risks. Chinese cabbage holds considerable importance as a leafy vegetable that is extensively consumed and cultivated worldwide. Its year-round production also encounters severe challenges in the face of high temperatures. In this study, melatonin (MT), a pivotal multifunctional signaling molecule that coordinates responses to diverse environmental stressors was used to mitigate the harmful effects of high temperatures on Chinese cabbage. Through the utilization of growth indices, cytological morphology, physiological and biochemical responses, and RNA-Seq analysis, alongside an examination of the influence of crucial enzymes in the endogenous MT synthesis pathway on the thermotolerance of Chinese cabbage, we revealed that MT pretreatment enhanced photosynthetic activity, maintained signaling pathways associated with endoplasmic reticulum protein processing, and preserved circadian rhythm in Chinese cabbage under high temperatures. Furthermore, pretreatment with MT resulted in increased levels of soluble sugar, vitamin C, proteins, and antioxidant enzyme activity, along with decreased levels of malondialdehyde, nitrate, flavonoids, and bitter glucosinolates, ultimately enhancing the capacity of the organism to mitigate oxidative stress. The knockdown of the tryptophan decarboxylase gene, which encodes a key enzyme responsible for MT biosynthesis, resulted in a significant decline in the ability of transgenic Chinese cabbage to alleviate oxidative damage under high temperatures, further indicating an important role of MT in establishing the thermotolerance. Taken together, these results provide a mechanism for MT to improve the antioxidant capacity of Chinese cabbage under high temperatures and suggest beneficial implications for the management of other plants subjected to global warming.
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Affiliation(s)
- Zhiyan Teng
- Laboratory of Cell & Molecular Biology, Institute of Vegetable Science, Zhejiang University, Hangzhou, 310058, China; Key Laboratory of Horticultural Plant Growth, Development and Quality Improvement, Ministry of Agriculture, Hangzhou, 310058, China
| | - Caizhi Chen
- Laboratory of Cell & Molecular Biology, Institute of Vegetable Science, Zhejiang University, Hangzhou, 310058, China; Key Laboratory of Horticultural Plant Growth, Development and Quality Improvement, Ministry of Agriculture, Hangzhou, 310058, China; Hainan Institute of Zhejiang University, Sanya, 572024, China
| | - Yuanrong He
- Laboratory of Cell & Molecular Biology, Institute of Vegetable Science, Zhejiang University, Hangzhou, 310058, China; Key Laboratory of Horticultural Plant Growth, Development and Quality Improvement, Ministry of Agriculture, Hangzhou, 310058, China; Hainan Institute of Zhejiang University, Sanya, 572024, China
| | - Shihui Pan
- Laboratory of Cell & Molecular Biology, Institute of Vegetable Science, Zhejiang University, Hangzhou, 310058, China; Key Laboratory of Horticultural Plant Growth, Development and Quality Improvement, Ministry of Agriculture, Hangzhou, 310058, China
| | - Dandan Liu
- Laboratory of Cell & Molecular Biology, Institute of Vegetable Science, Zhejiang University, Hangzhou, 310058, China; Key Laboratory of Horticultural Plant Growth, Development and Quality Improvement, Ministry of Agriculture, Hangzhou, 310058, China; Hainan Institute of Zhejiang University, Sanya, 572024, China
| | - Luyu Zhu
- Laboratory of Cell & Molecular Biology, Institute of Vegetable Science, Zhejiang University, Hangzhou, 310058, China; Key Laboratory of Horticultural Plant Growth, Development and Quality Improvement, Ministry of Agriculture, Hangzhou, 310058, China
| | - Kexin Liang
- Laboratory of Cell & Molecular Biology, Institute of Vegetable Science, Zhejiang University, Hangzhou, 310058, China; Key Laboratory of Horticultural Plant Growth, Development and Quality Improvement, Ministry of Agriculture, Hangzhou, 310058, China
| | - Yufei Li
- Laboratory of Cell & Molecular Biology, Institute of Vegetable Science, Zhejiang University, Hangzhou, 310058, China; Key Laboratory of Horticultural Plant Growth, Development and Quality Improvement, Ministry of Agriculture, Hangzhou, 310058, China
| | - Li Huang
- Laboratory of Cell & Molecular Biology, Institute of Vegetable Science, Zhejiang University, Hangzhou, 310058, China; Key Laboratory of Horticultural Plant Growth, Development and Quality Improvement, Ministry of Agriculture, Hangzhou, 310058, China; Hainan Institute of Zhejiang University, Sanya, 572024, China.
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4
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Wang B, Wang Z, Wang C, Wang X, Jia Z, Liu L. Elevated aerosol enhances plant water-use efficiency by increasing carbon uptake while reducing water loss. THE NEW PHYTOLOGIST 2024; 243:567-579. [PMID: 38812270 DOI: 10.1111/nph.19877] [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: 01/21/2024] [Accepted: 05/12/2024] [Indexed: 05/31/2024]
Abstract
Aerosols could significantly influence ecosystem carbon and water fluxes, potentially altering their interconnected dynamics, typically characterized by water-use efficiency (WUE). However, our understanding of the underlying ecophysiological mechanisms remains limited due to insufficient field observations. We conducted 4-yr measurements of leaf photosynthesis and transpiration, as well as 3-yr measurements of stem growth (SG) and sap flow of poplar trees exposed to natural aerosol fluctuation, to elucidate aerosol's impact on plant WUE. We found that aerosol improved sun leaf WUE mainly because a sharp decline in photosynthetically active radiation (PAR) inhibited its transpiration, while photosynthesis was less affected, as the negative effect induced by declined PAR was offset by the positive effect induced by low leaf vapor pressure deficit (VPDleaf). Conversely, diffuse radiation fertilization (DRF) effect stimulated shade leaf photosynthesis with minimal impact on transpiration, leading to an improved WUE. The responses were further verified by a strong DRF on SG and a decrease in sap flow due to the suppresses in total radiation and VPD. Our field observations indicate that, contrary to the commonly assumed coupling response, carbon uptake and water use exhibited dissimilar reactions to aerosol pollution, ultimately enhancing WUE at the leaf and canopy level.
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Affiliation(s)
- Bin Wang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- College of Life Sciences, Zhejiang University, Hangzhou, 310058, China
- University of Chinese Academy of Sciences, Yuquan Road, Beijing, 100049, China
| | - Zhenhua Wang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Yuquan Road, Beijing, 100049, China
- The Engineering Technology Research Center of Characteristic Medicinal Plants of Fujian, School of Life Sciences, Ningde Normal University, Ningde, 352101, China
| | - Chengzhang Wang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Yuquan Road, Beijing, 100049, China
| | - Xin Wang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- China National Botanical Garden, Beijing, 100093, China
| | - Zhou Jia
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Yuquan Road, Beijing, 100049, China
| | - Lingli Liu
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Yuquan Road, Beijing, 100049, China
- China National Botanical Garden, Beijing, 100093, China
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5
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Joshi RK, Gupta R, Mishra A, Garkoti SC. Seasonal variations of leaf ecophysiological traits and strategies of co-occurring evergreen and deciduous trees in white oak forest in the central Himalaya. ENVIRONMENTAL MONITORING AND ASSESSMENT 2024; 196:634. [PMID: 38900402 DOI: 10.1007/s10661-024-12771-3] [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: 10/08/2023] [Accepted: 05/25/2024] [Indexed: 06/21/2024]
Abstract
The present study investigates the seasonal variations in leaf ecophysiological traits and strategies employed by co-occurring evergreen and deciduous tree species within a white oak forest (Quercus leucotrichophora A. Camus) ecosystem in the central Himalaya. Seasonal variations in physiological, morphological, and chemical traits were observed from leaf initiation until senescence in co-occurring deciduous and evergreen tree species. We compared various parameters, including net photosynthetic capacity (Aarea and Amass), leaf stomatal conductance (gswarea and gswmass), transpiration rate (Earea and Emass), specific leaf area (SLA), mid-day water potential (Ψmd), leaf nitrogen (N) and phosphorus (P) concentration, leaf total chlorophyll concentration, photosynthetic nitrogen- and phosphorus-use efficiency (PNUE and PPUE), and water use efficiency (WUE) across four evergreen and four deciduous tree species. Our findings reveal that evergreen and deciduous trees exhibit divergent strategies in coping with seasonal changes, which are crucial for their survival and growth. Deciduous trees consistently exhibited significantly higher photosynthetic rates, transpiration rates, mass-based N and P concentrations (Nmass and Pmass), mass-based chlorophyll concentration (Chlmass), SLA, and leaf Ψmd, while maintaining lower leaf structural investments throughout the year compared to evergreen trees. These findings indicate that deciduous trees achieve greater assimilation rates per unit mass and higher nutrient-use efficiency. Physiological, morphological, and leaf N and P concentrations were higher in the summer (fully expanded leaf) than in the fall (senesced leaf). These insights provide valuable contributions to our understanding of tree species coexistence and their ecological roles in temperate forest ecosystems, with implications for forest management and conservation in the Himalayan region.
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Affiliation(s)
- Rajendra Kr Joshi
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
- Department of Environmental Sciences, Daulat Ram College, University of Delhi, New Delhi, 110007, India
| | - Rajman Gupta
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Ambuj Mishra
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Satish Chandra Garkoti
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.
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6
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Laoué J, Gea-Izquierdo G, Dupouyet S, Conde M, Fernandez C, Ormeño E. Leaf morpho-anatomical adjustments in a Quercus pubescens forest after 10 years of partial rain exclusion in the field. TREE PHYSIOLOGY 2024; 44:tpae047. [PMID: 38676920 DOI: 10.1093/treephys/tpae047] [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: 10/23/2023] [Revised: 04/11/2024] [Accepted: 04/23/2024] [Indexed: 04/29/2024]
Abstract
In the Mediterranean region, a reduction of annual precipitation and a longer and drier summer season are expected with climate change by the end of the century, eventually endangering forest survival. To cope with such rapid changes, trees may modulate their morpho-anatomical and physiological traits. In the present study, we focused on the variation in leaf gas exchange and different leaf morpho-anatomical functional traits of Quercus pubescens Willd. in summer using a long-term drought experiment in natura consisting of a dynamic rainfall exclusion system where trees have been submitted to amplified drought (AD) (~-30% of annual precipitation) since April 2012 and compared them with trees under natural drought (ND) in a Mediterranean forest. During the study, we analyzed net CO2 assimilation (An), stomatal conductance (gs), transpiration (E), water-use efficiency (WUE), stomatal size and density, density of glandular trichomes and non-glandular trichomes, thickness of the different leaf tissues, specific leaf area and leaf surface. Under AD, tree functioning was slightly impacted, since only An exhibited a 49% drop, while gs, E and WUE remained stable. The decrease in An under AD was regulated by concomitant lower stomatal density and reduced leaf thickness. Trees under AD also featured leaves with a higher non-glandular trichome density and a lower glandular trichome density compared with ND, which simultaneously limits transpiration and production costs. This study points out that Q. pubescens exhibits adjustments of leaf morpho-anatomical traits which can help trees to acclimate to AD scenarios as those expected in the future in the Mediterranean region.
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Affiliation(s)
- Justine Laoué
- CNRS, Aix Marseille Univ, Univ Avignon, IRD, IMBE, University Campus Saint-Jérôme 13013 Marseille, France
| | | | - Sylvie Dupouyet
- CNRS, Aix Marseille Univ, Univ Avignon, IRD, IMBE, University Campus Saint-Jérôme 13013 Marseille, France
| | - María Conde
- CIFOR-INIA, CSIC, Centro de Investigación Forestal Moncloa - Aravaca 28040 Madrid, Spain
| | - Catherine Fernandez
- CNRS, Aix Marseille Univ, Univ Avignon, IRD, IMBE, University Campus Saint-Jérôme 13013 Marseille, France
| | - Elena Ormeño
- CNRS, Aix Marseille Univ, Univ Avignon, IRD, IMBE, University Campus Saint-Jérôme 13013 Marseille, France
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7
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Ač A, Jansen MAK, Grace J, Urban O. Unravelling the neglected role of ultraviolet radiation on stomata: A meta-analysis with implications for modelling ecosystem-climate interactions. PLANT, CELL & ENVIRONMENT 2024; 47:1769-1781. [PMID: 38314642 DOI: 10.1111/pce.14841] [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: 11/03/2023] [Revised: 01/17/2024] [Accepted: 01/23/2024] [Indexed: 02/06/2024]
Abstract
Stomata play a pivotal role in regulating gas exchange between plants and the atmosphere controlling water and carbon cycles. Accordingly, we investigated the impact of ultraviolet-B radiation, a neglected environmental factor varying with ongoing global change, on stomatal morphology and function by a Comprehensive Meta-Analysis. The overall UV effect at the leaf level is to decrease stomatal conductance, stomatal aperture and stomatal size, although stomatal density was increased. The significant decline in stomatal conductance is marked (6% in trees and >10% in grasses and herbs) in short-term experiments, with more modest decreases noted in long-term UV studies. Short-term experiments in growth chambers are not representative of long-term field UV effects on stomatal conductance. Important consequences of altered stomatal function are hypothesized. In the short term, UV-mediated stomatal closure may reduce carbon uptake but also water loss through transpiration, thereby alleviating deleterious effects of drought. However, in the long term, complex changes in stomatal aperture, size, and density may reduce the carbon sequestration capacity of plants and increase vegetation and land surface temperatures, potentially exacerbating negative effects of drought and/or heatwaves. Therefore, the expected future strength of carbon sink capacity in high-UV regions is likely overestimated.
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Affiliation(s)
- Alexander Ač
- Global Change Research of the Czech Academy of Sciences, Brno, Czech Republic
| | - Marcel A K Jansen
- Global Change Research of the Czech Academy of Sciences, Brno, Czech Republic
- School of Biological, Earth and Environmental Sciences, Environmental Research Institute, UCC, Cork, Ireland
| | - John Grace
- Global Change Research of the Czech Academy of Sciences, Brno, Czech Republic
- School of GeoSciences, University of Edinburgh, Edinburgh, UK
| | - Otmar Urban
- Global Change Research of the Czech Academy of Sciences, Brno, Czech Republic
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8
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Patel J, Khatri K, Khandwal D, Gupta NK, Choudhary B, Hapani D, Koshiya J, Syed SN, Phillips DW, Jones HD, Mishra A. Modulation of physio-biochemical and photosynthesis parameters by overexpressing SbPIP2 gene improved abiotic stress tolerance of transgenic tobacco. PHYSIOLOGIA PLANTARUM 2024; 176:e14384. [PMID: 38859697 DOI: 10.1111/ppl.14384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 05/13/2024] [Accepted: 05/21/2024] [Indexed: 06/12/2024]
Abstract
The present study aims to explore the potential of a plasma-membrane localized PIP2-type aquaporin protein sourced from the halophyte Salicornia brachiata to alleviate salinity and water deficit stress tolerance in a model plant through transgenic intervention. Transgenic plants overexpressing SbPIP2 gene showed improved physio-biochemical parameters like increased osmolytes (proline, total sugar, and amino acids), antioxidants (polyphenols), pigments and membrane stability under salinity and drought stresses compared to control plants [wild type (WT) and vector control (VC) plants]. Multivariate statistical analysis showed that, under water and salinity stresses, osmolytes, antioxidants and pigments were correlated with SbPIP2-overexpressing (SbPIP2-OE) plants treated with salinity and water deficit stress, suggesting their involvement in stress tolerance. As aquaporins are also involved in CO2 transport, SbPIP2-OE plants showed enhanced photosynthesis performance than wild type upon salinity and drought stresses. Photosynthetic gas exchange (net CO2 assimilation rate, PSII efficiency, ETR, and non-photochemical quenching) were significantly higher in SbPIP2-OE plants compared to control plants (wild type and vector control plants) under both unstressed and stressed conditions. The higher quantum yield for reduction of end electron acceptors at the PSI acceptor side [Φ( R0 )] in SbPIP2-OE plants compared to control plants under abiotic stresses indicates a continued PSI functioning, leading to retained electron transport rate, higher carbon assimilation, and less ROS-mediated injuries. In conclusion, the SbPIP2 gene functionally validated in the present study could be a potential candidate for engineering abiotic stress resilience in important crops.
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Affiliation(s)
- Jaykumar Patel
- CSIR-Central Salt and Marine Chemicals Research Institute, Bhavnagar, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Kusum Khatri
- CSIR-Central Salt and Marine Chemicals Research Institute, Bhavnagar, India
| | - Deepesh Khandwal
- CSIR-Central Salt and Marine Chemicals Research Institute, Bhavnagar, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Nirmala Kumari Gupta
- CSIR-Central Salt and Marine Chemicals Research Institute, Bhavnagar, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Babita Choudhary
- CSIR-Central Salt and Marine Chemicals Research Institute, Bhavnagar, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Divya Hapani
- CSIR-Central Salt and Marine Chemicals Research Institute, Bhavnagar, India
| | - Jignasha Koshiya
- CSIR-Central Salt and Marine Chemicals Research Institute, Bhavnagar, India
| | - Saif Najam Syed
- CSIR-Central Salt and Marine Chemicals Research Institute, Bhavnagar, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Dylan Wyn Phillips
- Department of Life Sciences, Aberystwyth University, Aberystwyth, Ceredigion, United Kingdom
| | - Huw Dylan Jones
- Department of Life Sciences, Aberystwyth University, Aberystwyth, Ceredigion, United Kingdom
| | - Avinash Mishra
- CSIR-Central Salt and Marine Chemicals Research Institute, Bhavnagar, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
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9
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Kim GJ, Jo H, Cho MS, Noh NJ, Han SH, Khamzina A, Kim HS, Son Y. Photosynthetic responses of Larix kaempferi and Pinus densiflora seedlings are affected by summer extreme heat rather than by extreme precipitation. Sci Rep 2024; 14:5250. [PMID: 38438488 PMCID: PMC10912299 DOI: 10.1038/s41598-024-56120-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Accepted: 02/29/2024] [Indexed: 03/06/2024] Open
Abstract
The frequency and intensity of summer extreme climate events are increasing over time, and have a substantial negative effect on plants, which may be evident in their impact on photosynthesis. Here, we examined the photosynthetic responses of Larix kaempferi and Pinus densiflora seedlings to extreme heat (+ 3 °C and + 6 °C), drought, and heavy rainfall by conducting an open-field multifactor experiment. Leaf gas exchange in L. kaempferi showed a decreasing trend under increasing temperature, showing a reduction in the stomatal conductance, transpiration rate, and net photosynthetic rate by 135.2%, 102.3%, and 24.8%, respectively, in the + 6 °C treatment compared to those in the control. In contrast, P. densiflora exhibited a peak function in the stomatal conductance and transpiration rate under + 3 °C treatment. Furthermore, both species exhibited increased total chlorophyll contents under extreme heat conditions. However, extreme precipitation had no marked effect on photosynthetic activities, given the overall favorable water availability for plants. These results indicate that while extreme heat generally reduces photosynthesis by triggering stomatal closure under high vapor pressure deficit, plants employ diverse stomatal strategies in response to increasing temperature, which vary among species. Our findings contribute to the understanding of mechanisms underlying the photosynthetic responses of conifer seedlings to summer extreme climate events.
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Affiliation(s)
- Gwang-Jung Kim
- Division of Environmental Science and Ecological Engineering, Korea University, 145, Anam-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea
| | - Heejae Jo
- Division of Environmental Science and Ecological Engineering, Korea University, 145, Anam-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea
| | - Min Seok Cho
- Forest Technology and Management Research Center, National Institute of Forest Science, Pocheon, 11186, Republic of Korea
- Research Planning and Coordination Division, National Institute of Forest Science, Seoul, 02455, Republic of Korea
| | - Nam Jin Noh
- Department of Forest Resources, Kangwon National University, Chuncheon, 24341, Republic of Korea
| | - Seung Hyun Han
- Forest Technology and Management Research Center, National Institute of Forest Science, Pocheon, 11186, Republic of Korea
| | - Asia Khamzina
- Division of Environmental Science and Ecological Engineering, Korea University, 145, Anam-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea
| | - Hyung-Sub Kim
- Division of Environmental Science and Ecological Engineering, Korea University, 145, Anam-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea
- Institute of Life Science and Natural Resources Research, Korea University, Seoul, 02841, Republic of Korea
| | - Yowhan Son
- Division of Environmental Science and Ecological Engineering, Korea University, 145, Anam-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea.
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Diao H, Cernusak LA, Saurer M, Gessler A, Siegwolf RTW, Lehmann MM. Uncoupling of stomatal conductance and photosynthesis at high temperatures: mechanistic insights from online stable isotope techniques. THE NEW PHYTOLOGIST 2024; 241:2366-2378. [PMID: 38303410 DOI: 10.1111/nph.19558] [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: 11/20/2023] [Accepted: 01/12/2024] [Indexed: 02/03/2024]
Abstract
The strong covariation of temperature and vapour pressure deficit (VPD) in nature limits our understanding of the direct effects of temperature on leaf gas exchange. Stable isotopes in CO2 and H2 O vapour provide mechanistic insight into physiological and biochemical processes during leaf gas exchange. We conducted combined leaf gas exchange and online isotope discrimination measurements on four common European tree species across a leaf temperature range of 5-40°C, while maintaining a constant leaf-to-air VPD (0.8 kPa) without soil water limitation. Above the optimum temperature for photosynthesis (30°C) under the controlled environmental conditions, stomatal conductance (gs ) and net photosynthesis rate (An ) decoupled across all tested species, with gs increasing but An decreasing. During this decoupling, mesophyll conductance (cell wall, plasma membrane and chloroplast membrane conductance) consistently and significantly decreased among species; however, this reduction did not lead to reductions in CO2 concentration at the chloroplast surface and stroma. We question the conventional understanding that diffusional limitations of CO2 contribute to the reduction in photosynthesis at high temperatures. We suggest that stomata and mesophyll membranes could work strategically to facilitate transpiration cooling and CO2 supply, thus alleviating heat stress on leaf photosynthetic function, albeit at the cost of reduced water-use efficiency.
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Affiliation(s)
- Haoyu Diao
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, 8903, Switzerland
| | - Lucas A Cernusak
- College of Science and Engineering, James Cook University, Cairns, Qld, 4879, Australia
| | - Matthias Saurer
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, 8903, Switzerland
| | - Arthur Gessler
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, 8903, Switzerland
- Institute of Terrestrial Ecosystems, ETH Zurich, Zurich, 8092, Switzerland
| | - Rolf T W Siegwolf
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, 8903, Switzerland
| | - Marco M Lehmann
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, 8903, Switzerland
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Pernicová N, Hlaváčová M, Findurová H, Čáslavský J, Urban O, Klem K, Trnka M. Grain carbon isotopes indicate the ability of wheat plants to maintain enhanced intrinsic water-use efficiency even after short-term exposure to high temperatures and drought. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2023; 205:108155. [PMID: 37952365 DOI: 10.1016/j.plaphy.2023.108155] [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: 03/15/2023] [Revised: 09/29/2023] [Accepted: 10/31/2023] [Indexed: 11/14/2023]
Abstract
Minimizing the impact of heat and drought on crop yields requires varieties with effective protective mechanisms. We tested the hypothesis that even a short-term high temperature amplifies the negative effects of reduced water availability on leaf gas-exchange, but can induce long-lasting improvement in plant water-use efficiency after the stress period. Accordingly, three common varieties of winter wheat (Triticum aestivum) were grown under field conditions. During the stem extension, the plants were exposed to distinct temperatures (daily maximum 26 vs. 38 °C), water availabilities (75% of field water capacity vs. permanent wilting point), and their combination for 14 days. All treatments reduced light-saturated rates of CO2 assimilation and transpiration, particularly when heat and drought were combined. Drought enhanced water-use efficiency (WUE) in all varieties (31.4-36.4%), but not at high temperatures (decrease by 17-52%). Intrinsic WUE (iWUE), determined from the stable carbon isotope composition of grains, was enhanced by 7.9-37% in all treatments and varieties; however, not all changes were significant. The combination of heat and drought tended to increase total protein content in grains but reduced spike productivity. Noticeably, the strongest decline in spike productivity was observed in Elan - the variety displaying the smallest enhancement of iWUE, while it was negligible in Pannonia which shows the most pronounced improvement of iWUE. We conclude that even several hot and dry days can improve iWUE for the rest of the vegetation season. This improvement, however, does not necessarily lead to increased crop productivity possibly due to physiological trade-offs.
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Affiliation(s)
- Natálie Pernicová
- Mendel University in Brno, Department of Agrosystems and Bioclimatology, Zemědělská 1, CZ-613 00, Brno, Czech Republic; Global Change Research Institute, Czech Academy of Sciences, Bělidla 986/4a, CZ-603 00, Brno, Czech Republic
| | - Marcela Hlaváčová
- Mendel University in Brno, Department of Agrosystems and Bioclimatology, Zemědělská 1, CZ-613 00, Brno, Czech Republic; Global Change Research Institute, Czech Academy of Sciences, Bělidla 986/4a, CZ-603 00, Brno, Czech Republic
| | - Hana Findurová
- Mendel University in Brno, Department of Agrosystems and Bioclimatology, Zemědělská 1, CZ-613 00, Brno, Czech Republic; Global Change Research Institute, Czech Academy of Sciences, Bělidla 986/4a, CZ-603 00, Brno, Czech Republic
| | - Josef Čáslavský
- Global Change Research Institute, Czech Academy of Sciences, Bělidla 986/4a, CZ-603 00, Brno, Czech Republic
| | - Otmar Urban
- Global Change Research Institute, Czech Academy of Sciences, Bělidla 986/4a, CZ-603 00, Brno, Czech Republic.
| | - Karel Klem
- Mendel University in Brno, Department of Agrosystems and Bioclimatology, Zemědělská 1, CZ-613 00, Brno, Czech Republic; Global Change Research Institute, Czech Academy of Sciences, Bělidla 986/4a, CZ-603 00, Brno, Czech Republic
| | - Miroslav Trnka
- Mendel University in Brno, Department of Agrosystems and Bioclimatology, Zemědělská 1, CZ-613 00, Brno, Czech Republic; Global Change Research Institute, Czech Academy of Sciences, Bělidla 986/4a, CZ-603 00, Brno, Czech Republic
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