Effects of drought on photosynthesis in grapevines under field conditions: an evaluation of stomatal and mesophyll limitations

2002 ◽  
Vol 29 (4) ◽  
pp. 461 ◽  
Author(s):  
Jaume Flexas ◽  
Josefina Bota ◽  
José M. Escalona ◽  
Bartolomé Sampol ◽  
Hipólito Medrano

The effect of diffusional and photochemical limitations to photosynthesis was assessed in field-grown water-stressed grapevines (Vitis vinifera L.) by combined measurements of gas exchange and chlorophyll fluorescence. Drought was slowly induced, and the progressive decline of photosynthesis was examined in different grapevine cultivars along a continuous gradient of maximum mid-morning values of stomatal conductance (g), which were used as an integrative indicator of the water-stress conditions endured by the leaves. Initial decreases of g were accompanied by decreases of substomatal CO2 concentration (Ci), the estimated chloroplastic CO2 concentration (Cc) and net photosynthesis (AN), while electron transport rate (ETR) remained unaffected. With increasing drought, g, AN, Ci and Cc further decreased, accompanied by slight decreases of ETR and of the estimated mesophyll conductance (gmes). Severe drought led to strong reductions of both g and gmes, as well as of ETR. The apparent carboxylation efficiency and the compensation point for CO2 remained unchanged under severe drought when analysed on a Cc, rather than a Ci, basis, suggesting that previously reported metabolic impairment was probably due to decreased gmes.

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 793
Author(s):  
Juanli Chen ◽  
Xueyong Zhao ◽  
Yaqiu Zhang ◽  
Yuqiang Li ◽  
Yongqing Luo ◽  
...  

Artemisia halodendron is a widely distributed native plant in China’s Horqin sandy land, but few studies have examined its physiological responses to drought and rehydration. To provide more information, we investigated the effects of drought and rehydration on the chlorophyll fluorescence parameters and physiological responses of A. halodendron to reveal the mechanisms responsible for A. halodendron’s tolerance of drought stress and the resulting ability to tolerate drought. We found that A. halodendron had strong drought resistance. Its chlorophyll content first increased and then decreased with prolonged drought. Variable chlorophyll fluorescence (Fv) and quantum efficiency of photosystem II (Fv/Fm) decreased, and the membrane permeability and malondialdehyde increased. When plants were subjected to drought stress, superoxide dismutase (SOD) activity degraded under severe drought, but the activities of peroxidase (POD) and catalase (CAT) and the contents of soluble proteins, soluble sugars, and free proline increased. Severe drought caused wilting of A. halodendron leaves and the leaves failed to recover even after rehydration. After rehydration, the chlorophyll content, membrane permeability, SOD and CAT activities, and the contents of the three osmoregulatory substances under moderate drought began to recover. However, Fv, Fv/Fm, malondialdehyde, and POD activity did not recover under severe drought. These results illustrated that drought tolerance of A. halodendron resulted from increased enzyme (POD and CAT) activities and accumulation of osmoregulatory substances.


2021 ◽  
Author(s):  
Xinjun Zhang ◽  
Wenting Liu ◽  
Yaci Lv ◽  
Tianliang Li ◽  
Jianzhao Tang ◽  
...  

Abstract Revealing the effects of drought stress during the critical period on the photosynthetic characteristics and production performance of naked oats could provide theoretical basis for optimizing the water managements and selecting the drought resistance cultivars. In this study, a potted experiment consisting of four water levels was conducted, to investigate the response of photosynthesis, chlorophyll fluorescence, biomass, yield and yield components of to drought stress during 12-15 days before heading at a typical site in Zhangjiakou. Results showed that the initial chlorophyll fluorescence rate (Fo) increased by 9.03-50.92% under drought stress, while the maximum fluorescence rate (Fm) and photochemical efficiency (Fv/Fm) decreased by 8.49-19.73% and 10.37-24.12%. Moreover drought stress decreased the photosynthetic rate (Pn), transpiration rate (Tr), stomatal conductance (Gs). The CO2 concentration (Ci) decreased under light drought stress, while increased under moderate and severe drought stress. Drought stress during critical periods also had significant impacts on oat yield and yield components. Oat yields decreased by 9.5-12.7%, 16.8-27.0% and 44.1-47.7% under light, moderate and sever drought stress, respectively. The yield components such as grains per spike, 1000-grain weight were decreased by 1.7-12.5%, 8.3-24.3%, 32.7-34.2% and 5.7-8.6%, 12.7-14.5%, 16.8-19.1% under light, moderate and severe drought stress, respectively. But the Spike numbers were not signifigantly different between different treatments. Our study explored the impacts of drought stress on the photosynthetic characteristics and production performance of naked oats, which had significance for enhancing the production efficiency for oat under drought stress.


2021 ◽  
Vol 12 ◽  
Author(s):  
Shuang Li ◽  
Junming Liu ◽  
Hao Liu ◽  
Rangjian Qiu ◽  
Yang Gao ◽  
...  

Drought reduces leaf stomatal conductance (gs) and mesophyll conductance (gm). Both hydraulic signals and chemical signals (mainly abscisic acid, ABA) are involved in regulating gs. However, it remains unclear what role the endogenous ABA plays in gm under decreasing soil moisture. In this study, the responses of gs and gm to ABA were investigated under progressive soil drying conditions and their impacts on net photosynthesis (An) and intrinsic water use efficiency (WUEi) were also analyzed. Experimental tomato plants were cultivated in pots in an environment-controlled greenhouse. Reductions of gs and gm induced a 68–78% decline of An under drought conditions. While soil water potential (Ψsoil) was over −1.01 MPa, gs reduced as leaf water potential (Ψleaf) decreased, but ABA and gm kept unchanged, which indicating gs was more sensitive to drought than gm. During Ψsoil reduction from −1.01 to −1.44 MPa, Ψleaf still kept decreasing, and both gs and gm decreased concurrently following to the sustained increases of ABA content in shoot sap. The gm was positively correlated to gs during a drying process. Compared to gs or gm, WUEi was strongly correlated with gm/gs. WUEi improved within Ψsoil range between −0.83 and −1.15 MPa. In summary, gs showed a higher sensitivity to drought than gm. Under moderate and severe drought at Ψsoil ≤ −1.01 MPa, furthermore from hydraulic signals, ABA was also involved in this co-ordination reductions of gs and gm and thereby regulated An and WUEi.


2020 ◽  
Vol 40 (4) ◽  
pp. 484-497 ◽  
Author(s):  
Yansen Xu ◽  
Bo Shang ◽  
Zhaozhong Feng ◽  
Lasse Tarvainen

Abstract Although ozone (O3) concentration and nitrogen (N) availability are well known to affect plant physiology, their impacts on the photosynthetic temperature response are poorly understood. We addressed this knowledge gap by exposing seedlings of hybrid poplar clone ‘107’ (Populous euramericana cv. ‘74/76’) to elevated O3 (E-O3) and N availability variation in a factorial experiment. E-O3 decreased light-saturated net photosynthesis (Asat), mesophyll conductance (gm) and apparent maximum rate of carboxylation (Vcmax, based on intercellular CO2 concentration) but not actual Vcmax (based on chloroplast CO2 concentration) and increased respiration in light (Rd) at 25 °C. Nitrogen fertilization increased Asat, gm, Vcmax and the maximum rate of electron transport (Jmax) and reduced Rd at 25 °C and the activation energy of actual Vcmax. No E-O3 or E-O3 x N interaction effects on the temperature response parameters were detected, simplifying the inclusion of O3 impacts on photosynthesis in vegetation models. gm peaked at 30 °C, apparent Vcmax and Jmax at 32–33 °C, while the optimum temperatures of actual Vcmax and Jmax exceeded the measured temperature range (15–35 °C). Ignoring gm would, thus, have resulted in mistakenly attributing the decrease in Asat at high temperatures to reduced biochemical capacity rather than to greater diffusion limitation.


Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 354
Author(s):  
El-Sayed M. Desoky ◽  
Elsayed Mansour ◽  
Mohamed M. A. Ali ◽  
Mohamed A. T. Yasin ◽  
Mohamed I. E. Abdul-Hamid ◽  
...  

The influence of 24-epibrassinolide (EBR24), applied to leaves at a concentration of 5 μM, on plant physio-biochemistry and its reflection on crop water productivity (CWP) and other agronomic traits of six maize hybrids was field-evaluated under semi-arid conditions. Two levels of irrigation water deficiency (IWD) (moderate and severe droughts; 6000 and 3000 m3 water ha−1, respectively) were applied versus a control (well-watering; 9000 m3 water ha−1). IWD reduced the relative water content, membrane stability index, photosynthetic efficiency, stomatal conductance, and rates of transpiration and net photosynthesis. Conversely, antioxidant enzyme activities and osmolyte contents were significantly increased as a result of the increased malondialdehyde content and electrolyte leakage compared to the control. These negative influences of IWD led to a reduction in CWP and grain yield-related traits. However, EBR24 detoxified the IWD stress effects and enhanced all the above-mentioned parameters. The evaluated hybrids varied in drought tolerance; Giza-168 was the best under moderate drought, while Fine-276 was the best under severe drought. Under IWD, certain physiological traits exhibited a highly positive association with yield and yield-contributing traits or CWP. Thus, exogenously using EBR24 for these hybrids could be an effective approach to improve plant and water productivity under reduced available water in semi-arid environments.


Plants ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 71
Author(s):  
María Carmen Antolín ◽  
María Toledo ◽  
Inmaculada Pascual ◽  
Juan José Irigoyen ◽  
Nieves Goicoechea

(1) Background: The associated increase in global mean surface temperature together with raised atmospheric carbon dioxide (CO2) concentration is exerting a profound influence on grapevine development (phenology) and grape quality. The exploitation of the local genetic diversity based on the recovery of ancient varieties has been proposed as an interesting option to cope with climate change and maintaining grape quality. Therefore, this research aimed to characterize the potential fruit quality of genotypes from seven local old grapevine varieties grown under climate change conditions. (2) Methods: The study was carried out on fruit-bearing cuttings (one cluster per plant) that were grown in pots in temperature gradient greenhouses (TGG). Two treatments were applied from fruit set to maturity: (1) ambient CO2 (400 ppm) and temperature (T) (ACAT) and (2) elevated CO2 (700 ppm) and temperature (T + 4 °C) (ECET). (3) Results: Results showed that some of the old genotypes tested remained quite stable during the climate change conditions in terms of fruit quality (mainly, total soluble solids and phenolic content) and of must antioxidant properties. (4) Conclusion: This research underlines the usefulness of exploiting local grapevine diversity to cope with climate change successfully, although further studies under field conditions and with whole plants are needed before extrapolating the results to the vineyard.


Atmosphere ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 845
Author(s):  
Qingtao Zhang ◽  
Yixuan Chen ◽  
Yujiu Xiong ◽  
Shigeoki Moritani ◽  
Xinyu Wu ◽  
...  

To better understand the sensitivity of berry size and grapevine photosynthesis to water stress, and determine the soil water potential (ψ) threshold for scheduling irrigation during the maturation stage, we simultaneously measured berry size with photographs, leaf net photosynthesis with a portable meter, and ψ with tensiometers during the drying cycles for grapevines (Vitis vinifera L.). Our results showed that in berry development stage III (maturation), photosynthesis was more sensitive to water stress than berry size. When ψ decreased beyond −13.2 ± 0.82 kPa, photosynthesis, stomatal conductance, transpiration, and extrinsic (AN/E) and intrinsic (AN/gs) water use efficiency (WUE) decreased rapidly and did not recover thereafter. In contrast, the berry size remained close to unaffected by the decreasing ψ until it reached a value of −16.2 ± 0.77 kPa and, thereafter, the berry shrank significantly. In conclusion, we suggest that during the maturation stage of grapevines, for the potted mixture used in our experiments, irrigation should be triggered when the ψ reaches a value of −13.2 ± 0.82 kPa. Further, ψ should be kept lower than −6.9 ± 0.15 kPa after irrigation, because the highest values of intrinsic WUE (AN/gs) occurred when ψ decreased from −6.9 ± 0.15 to −14.6 ± 0.7 kPa. In arid areas, the threshold ψ should be considered as −16.2 ± 0.77 kPa during maturation to achieve high-efficiency use of water resources and sustainable production of grapevines.


Cells ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 261
Author(s):  
Md. Mahadi Hasan ◽  
Milan Skalicky ◽  
Mohammad Shah Jahan ◽  
Md. Nazmul Hossain ◽  
Zunaira Anwar ◽  
...  

In recent years, research on spermine (Spm) has turned up a lot of new information about this essential polyamine, especially as it is able to counteract damage from abiotic stresses. Spm has been shown to protect plants from a variety of environmental insults, but whether it can prevent the adverse effects of drought has not yet been reported. Drought stress increases endogenous Spm in plants and exogenous application of Spm improves the plants’ ability to tolerate drought stress. Spm’s role in enhancing antioxidant defense mechanisms, glyoxalase systems, methylglyoxal (MG) detoxification, and creating tolerance for drought-induced oxidative stress is well documented in plants. However, the influences of enzyme activity and osmoregulation on Spm biosynthesis and metabolism are variable. Spm interacts with other molecules like nitric oxide (NO) and phytohormones such as abscisic acid, salicylic acid, brassinosteroids, and ethylene, to coordinate the reactions necessary for developing drought tolerance. This review focuses on the role of Spm in plants under severe drought stress. We have proposed models to explain how Spm interacts with existing defense mechanisms in plants to improve drought tolerance.


2009 ◽  
Vol 36 (7) ◽  
pp. 645 ◽  
Author(s):  
Dennis H. Greer ◽  
Sylvie M. Sicard

Assessing the impacts of environmental stresses on plant growth and productivity requires an understanding of the growth processes and the carbon economy that underpins this growth. Potted grapevines of the Vitis vinifera L. cv. Semillon were grown in a controlled environment and canopy growth; leaf, bunch and stem extension and net photosynthesis were routinely measured from budbreak to harvest. Allometric relationships enabled dry matter to be determined and, with net photosynthesis, used to determine the shoot carbon economy. Stems, leaves and bunches all followed a sigmoid growth pattern with leaves and stems allocated similar amounts of biomass and carbon while bunches had twice as much. Rates of carbon sequestered as biomass exceeded rates of carbon acquisition through net photosynthesis for over 25 days after budbreak. Despite the high demand for biomass in bunch growth, rates of carbon sequestration actually declined and overall, the vines maintained a positive carbon balance throughout the period of bunch growth. The Semillon shoots relied on carbon reserves to commence growth then produced a 53% carbon surplus after leaf (9%), stem (10%) and bunch (28%) growth demands were satisfied. This suggests these vines also allocated carbon to reserves to sustain the next season’s growth.


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