scholarly journals Drought stress imposes reversible photosynthetic damage under fluctuating light conditions in crops

Author(s):  
Kazuma Sakoda ◽  
Kazuki Taniyoshi ◽  
Wataru Yamori ◽  
Yu Tanaka

Drought stress is a major limiting factor for crop growth and yield. Water availability in the field can cyclically change between drought and rewatering conditions, depending on precipitation patterns. Concurrently, light intensity under field conditions can fluctuate, inducing dynamic photosynthesis and transpiration during crop growth period. The present study aimed to characterize carbon gain and water use in fluctuating light under drought and rewatering conditions by conducting gas exchange measurements in two major crops, namely rice and soybean. In both crops, drought stress reduced steady-state photosynthesis and/or photosynthetic capacity, and delayed photosynthetic induction even when it had relatively small impact on photosynthetic capacity, suggesting that the drought effects on photosynthesis should be evaluated based on induction, maximum, and steady states. This delayed photosynthetic induction resulted in a substantial loss of carbon gain under fluctuating light conditions, which can be a limiting factor for crop growth and yield in the field. Meanwhile, rewatering after drought conditions completely recovered photosynthetic capacity and induction in both crops, whereas drought experience would be memorized to slow down the stomatal opening. Therefore, the stability of photosynthetic induction can be a promising target to improve drought tolerance during crop breeding in the future.

Author(s):  
Hu Sun ◽  
Qi Shi ◽  
Ning-Yu Liu ◽  
Shi-Bao Zhang ◽  
Wei Huang

Fluctuating light (FL) and drought stress usually occur concomitantly. However, whether drought stress affects photosynthetic performance under FL remains unknown. Here, we measured gas exchange, chlorophyll fluorescence, and P700 redox state under FL in drought-stressed tomato (Solanum lycopersicum) seedlings. Drought stress significantly affected stomatal opening and mesophyll conductance after transition from low to high light and thus delayed photosynthetic induction under FL. Therefore, drought stress exacerbated the loss of carbon gain under FL. Furthermore, restriction of CO2 fixation under drought stress aggravated the over-reduction of photosystem I (PSI) upon transition from low to high light. The resulting stronger FL-induced PSI photoinhibition significantly supressed linear electron flow and PSI photoprotection. These results indicated that drought stress not only affected gas exchange under FL but also accelerated FL-induced photoinhibition of PSI. Furthermore, drought stress enhanced relative cyclic electron flow in FL, which partially compensated for restricted CO2 fixation and thus favored PSI photoprotection under FL. Therefore, drought stress has large effects on photosynthetic dark and light reactions under FL.


2021 ◽  
Author(s):  
Hu Sun ◽  
Qi Shi ◽  
Ning-Yu Liu ◽  
Shi-Bao Zhang ◽  
Wei Huang

Fluctuating light (FL) and drought stress usually occur concomitantly. However, whether drought stress affects photosynthetic performance under FL remains unknown. Here, we measured gas exchange, chlorophyll fluorescence, and P700 redox state under FL in drought-stressed tomato (Solanum lycopersicum) seedlings. Drought stress significantly affected stomatal opening and mesophyll conductance after transition from low to high light and thus delayed photosynthetic induction under FL. Therefore, drought stress exacerbated the loss of carbon gain under FL. Furthermore, restriction of CO2 fixation under drought stress aggravated the over-reduction of photosystem I (PSI) upon transition from low to high light. The resulting stronger FL-induced PSI photoinhibition significantly supressed linear electron flow and PSI photoprotection. These results indicated that drought stress not only affected gas exchange under FL but also accelerated FL-induced photoinhibition of PSI. Furthermore, drought stress enhanced relative cyclic electron flow in FL, which partially compensated for restricted CO2 fixation and thus favored PSI photoprotection under FL. Therefore, drought stress has large effects on photosynthetic dark and light reactions under FL.


2007 ◽  
Vol 37 (9) ◽  
pp. 1714-1722 ◽  
Author(s):  
Heather M. Joesting ◽  
Brian C. McCarthy ◽  
Kim J. Brown

Restoration attempts to reintroduce American chestnut trees to the eastern deciduous forest by means of a disease-resistant Chinese–American hybrid seed are in progress. Knowing the light conditions required for optimum seedling performance is necessary to maximize the success of reintroduction. American chestnut ( Castanea dentata (Marsh.) Borkh.) seedlings were planted in two replicate forests in Vinton County, Ohio, in areas that had been thinned (more available light) and in control areas (intact canopy, less available light). The photosynthetic capacity of 12 seedlings per treatment was assessed using an infrared gas-exchange analyzer. Seedlings in the thinned treatment reached light-saturating rates of photosynthesis at an irradiance level approximately 33% higher than did the seedlings in the control treatment. Seedlings grown in the thinned treatment had a significantly greater maximum rate of photosynthesis (Amax), dark respiration rate (Rd), and daily carbon gain per seedling than seedlings grown in the control treatment. The light compensation point (LCP), quantum efficiency (ϕ), leaf mass per area (LMA), and leaf nitrogen concentration per unit leaf area (Narea) were not significantly different between treatments. American chestnut seedlings in the thinned treatment clearly maximize leaf-level photosynthetic capacity. These results will aid land managers in planning reintroduction trials by providing information on the light conditions required for maximum seedling success.


2019 ◽  
Vol 70 (19) ◽  
pp. 5287-5297 ◽  
Author(s):  
Shunsuke Adachi ◽  
Yu Tanaka ◽  
Atsuko Miyagi ◽  
Makoto Kashima ◽  
Ayumi Tezuka ◽  
...  

The high-yielding rice cultivar Takanari has fast photosynthetic induction owing to a high electron transport rate, stomatal conductance, and metabolic flux, leading to high daily carbon gain under fluctuating light.


2021 ◽  
Vol 12 ◽  
Author(s):  
Huixing Kang ◽  
Ting Zhu ◽  
Yan Zhang ◽  
Xinran Ke ◽  
Wenjuan Sun ◽  
...  

Crops developed under elevated carbon dioxide (eCO2) exhibit enhanced leaf photosynthesis under steady states. However, little is known about the effect of eCO2 on dynamic photosynthesis and the relative contribution of the short-term (substrate) and long-term (acclimation) effects of eCO2. We grew an Oryza sativa japonica cultivar and a Triticum aestivum cultivar under 400 μmol CO2 mol−1 air (ambient, A) and 600 μmol CO2 mol−1 air (elevated, E). Regardless of growth [CO2], the photosynthetic responses to the sudden increase and decrease in light intensity were characterized under 400 (a) or 600 μmol CO2 mol−1 air (e). The Aa1, Ae2, Ea3, and Ee4 treatments were employed to quantify the acclimation effect (Ae vs. Ee and Aa vs. Ea) and substrate effect (Aa vs. Ae and Ea vs. Ee). In comparison with the Aa treatment, both the steady-state photosynthetic rate (PN) and induction state (IS) were higher under the Ae and Ee treatments but lower under the Ea treatment in both species. However, IS reached at the 60 sec after the increase in light intensity, the time required for photosynthetic induction, and induction efficiency under Ae and Ee treatment did not differ significantly from those under Aa treatment. The substrate effect increased the accumulative carbon gain (ACG) during photosynthetic induction by 45.5% in rice and by 39.3% in wheat, whereas the acclimation effect decreased the ACG by 18.3% in rice but increased it by 7.5% in wheat. Thus, eCO2, either during growth or at measurement, enhances the dynamic photosynthetic carbon gain in both crop species. This indicates that photosynthetic carbon loss due to an induction limitation may be reduced in the future, under a high-CO2 world.


Agronomy ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 712 ◽  
Author(s):  
Omena Ojuederie ◽  
Oluwaseyi Olanrewaju ◽  
Olubukola Babalola

Abiotic stresses arising from climate change negates crop growth and yield, leading to food insecurity. Drought causes oxidative stress on plants, arising from excessive production of reactive oxygen species (ROS) due to inadequate CO2, which disrupts the photosynthetic machinery of plants. The use of conventional methods for the development of drought-tolerant crops is time-consuming, and the full adoption of modern biotechnology for crop enhancement is still regarded with prudence. Plant growth-promoting rhizobacteria (PGPR) could be used as an inexpensive and environmentally friendly approach for enhancing crop growth under environmental stress. The various direct and indirect mechanisms used for plant growth enhancement by PGPR were discussed. Synthesis of 1-aminocyclopropane−1-carboxylate (ACC) deaminase enhances plant nutrient uptake by breaking down plant ACC, thereby preventing ethylene accumulation, and enable plants to tolerate water stress. The exopolysaccharides produced also improves the ability of the soil to withhold water. PGPR enhances osmolyte production, which is effective in reducing the detrimental effects of ROS. Multifaceted PGPRs are potential candidates for biofertilizer production to lessen the detrimental effects of drought stress on crops cultivated in arid regions. This review proffered ways of augmenting their efficacy as bio-inoculants under field conditions and highlighted future prospects for sustainable agricultural productivity.


2021 ◽  
Author(s):  
Hu Sun ◽  
Yu-Qi Zhang ◽  
Shi-Bao Zhang ◽  
Wei Huang

The response of photosynthetic CO2 assimilation to changes of illumination affects plant growth and crop productivity under natural fluctuating light conditions. However, the effects of nitrogen (N) supply on photosynthetic physiology after transition from low to high light are seldom studied. To elucidate this, we measured gas exchange and chlorophyll fluorescence under fluctuating light in tomato (Solanum lycopersicum) seedlings grown with different N conditions. After transition from low to high light, the induction speeds of net CO2 assimilation (AN), stomatal conductance (gs) and mesophyll conductance (gm) delayed with the decline in leaf N content. The times to reach 90% of maximum AN, gs and gm were negatively correlated to leaf N content. This delayed photosynthetic induction in plants grown under low N concentration was mainly caused by the slow induction response of gm rather than that of gs. Furthermore, the photosynthetic induction upon transfer from low to high light was hardly limited by photosynthetic electron flow. These results indicate that decreased leaf N content declines carbon gain under fluctuating light in tomato. Increasing the induction kinetics of gm has the potential to enhance the carbon gain of field crops grown in infertile soil.


Author(s):  
Nicole Salvatori ◽  
Fabrizio Carteni ◽  
Francesco Giannino ◽  
Giorgio Alberti ◽  
Stefano Mazzoleni ◽  
...  

It has been recognized the need to consider some photosynthetic processes in their transient states since those are more representative of the natural environment. The combination of mathematical models with the available data provides a tool to understand the dynamic responses of plants to fluctuating environments and can be used to make predictions on how photosynthesis would respond to unsteady state conditions. Here we present a leaf level system dynamic photosynthetic model based and validated on an experiment performed on two soybean varieties, the wildtype Eiko and the chlorophyll deficient mutant Minngold, grown in constant and fluctuating light conditions. This mutant is known to have similar steady-state photosynthesis compared to the green wildtype, but it is found to have less biomass at harvest. It has been hypothesized that this might be due to an unoptimized response to non-steady state conditions, therefore this mutant seems relevant to investigate dynamic photosynthesis. The model explained well the photosynthetic responses of these two varieties to fluctuating and constant light conditions and allowed to make relevant conclusions on the different dynamic responses of the two varieties. Furthermore, due to its simplicity, the model could provide the basis of an upscaled dynamic model at plant level.


2018 ◽  
Vol 14 (3) ◽  
pp. 211
Author(s):  
Maimunah Maimunah ◽  
Gusti Rusmayadi ◽  
Bambang F. Langai

Soybean is categorized as a plant which sensitive to water deficit or surplus in its life cycle. If water requirement is not sufficient for the growth and development, the soybean will be subjected to stress. Water stress, such deficiency or excess of water in the plant environment is a condition that disrupts the balance of plant growth. Therefore, it is necessary to observe the interaction between drought stress at various growth stages and soybean varieties, and observe which growth stages that would provide the highest yield of soybean know the differences in drought stress in various stadia of plant growth on the growth and yield of two varieties of soybean crops and which currently can give the highest yield in various stadia grow. This research was carried out by using polybag in the greenhouse of Faculty of Agriculture Universitas Lambung Mangkurat Banjarbaru for 4 months from March to June 2017. The experimental design was Randomized Completely Design with Split Plot Design Factorial. The first factor is soybean varieties (V) as main plot, i.e. Grobogan (v1) and Anjasmoro (v2), and the second factor is the growth stages those subjected to drought stress (C) as subplot, i.e. c1 : vegetative stage 3 (29 DAS and 36 DAS), c2 : flowering stage (35 DAS and 46 DAS), c3 pods appearance/emergence (42 DAS and 53 DAS), and c4 : pods filling stage (68 DAS and 76 DAS). The treatment was repeated 3 times and each experiment unit consists of 5 polybags, thus there were 120 plants in total. The crop growth rate, number of main branch nodes, number of effective root nodules, shoot root ratio, the first flowering time, the harvest time, number of pods per plant, number of seed per plant, 100 seed dry weight, and the number of dry seed per plant. The result showed there was no interaction effect between drought stress in various stages and soybean varieties on all variables. Drought stress at vegetative stage 3 (c1) caused the number of main branch nodes, the number of pods per plant, the number of seed per plant, the 100 seed dry weight and the number of dry seed per plant are lower if they are compared to the plants those subjected to drought stress at pod filling stage (c4). Nevertheless, those variables were not different at drought stress at flowering stage (c2), pods appearance (c3) and pod filling stage  (4). Soybean varieties observation showed that the Grobogan were faster in flowering time and higher in crop growth (26.49 DAS and 3.08 g d-1 respectively) compared to the Anjasmoro (34.08 DAS and 2.73 g d-1 respectively).


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