Changes in the photosynthetic efficiency of winter wheat in response to abiotic stress

Abstract

Changes in the photosynthetic efficiency of winter wheat in response to abiotic stress Abbreviations:Ci -intercellular CO 2 concentration; D -drought stress; D+H -drought + heat stress; E -transpiration; Fat -Fatima 2; g s -stomatal conductance; H -heat stress; Mag -Mv Magma; PAM -pulse amplitude modulated fluorometer; Pla -Plainsman V.; P N -net assimilation rate; Φ PSII -effective quantum yield of PSII IntroductionTemperature and drought have an extremely complex effect on the intensity of photosynthesis, as they influence numerous physiological processes, which in turn exert an effect on photosynthetic activity [1]. The optimum functioning of photosynthetic processes may depend on a number of other factors, including light intensity, CO 2 concentration, the plant's water balance, and whether the plants investigated are of the C3 or C4 type. Many factors may lead to a deterioration in photosynthetic intensity if they are not satisfactory for the plant.Various studies show that photosynthesis in wheat leaves starts to decline at temperatures between 28 and 35°C [2,3]. Heat stress during the reproductive phase may cause pollen sterility, tissue dehydration and lower CO 2 assimilation [1]. High temperatures injure the processes responsible for light gathering and light energy conversion, while increasing the level of photorespiration. The light-harvesting chlorophyllprotein complex may be irreversibly severed from the reaction centre nucleus, and the water-splitting system responsible for oxygen generation may also be Keywords: Heat stress • Drought • Photosynthesis • Grain yield • Grain filling • Winter wheatAbstract: The assessment of heat and drought tolerance is of primary importance in breeding programmes designed to improve heat and drought tolerance in cereals. Three winter wheat varieties grown in controlled growth chambers were exposed to heat (H) and drought (D) stress singly and in combination (H+D). The combined effects of H and D stress were much more severe than those of individual treatments for both physiological and yield parameters during grain filling. The chlorophyll content, effective quantum yield of PSII, net assimilation rate, transpiration, stomatal conductance and intercellular CO 2 concentration were greatly reduced by H, D and their interaction. Grain yield decreased to a greater extent (48.3%) in Plainsman V, averaged over the stress treatments, than in Mv Magma (67.8%) and Fatima 2 (53.7%). The least decline was found in grain number, except in Plainsman V. Mv Magma tolerated heat stress better than Fatima 2. In terms of photosynthetic activity, Plainsman V showed better drought tolerance than Mv Magma. The results showed that changes in physiological properties during stress treatment are not always associated with changes in yield parameters, so a combination of methods may be needed to give a more precise picture of the stress tolerance of wheat varieties.

Wheat Line “RYNO3936” Is Associated With Delayed Water Stress-Induced Leaf Senescence and Rapid Water-Deficit Stress Recovery

“…Photosynthetic activity in plants has been shown to be a trait that is highly responsive to water deficit stress (Singh et al, 2014;Serba and Yadav, 2016;Perdomo et al, 2017). In wheat, a direct correlation exists between imposed water-deficit stress and decreases in photosynthetic rate, leading to changes in intercellular CO 2 concentration, stomatal conductance, and transpiration rate (Subrahmanyam et al, 2006;Balla et al, 2014;Sharifi and Mohammadkhani, 2016;Perdomo et al, 2017;Senapati et al, 2018). Water deficit stress negatively affects maximal quantum yield of PSII photochemistry (F v /F m ) (Tian et al, 2017), and damages the oxygen-evolving complex of PSII and its reaction centers (Aro, 2004;Murata et al, 2007;Tian et al, 2017).…”

Water stress altered photosynthesis‐vegetation index relationships for winter wheat

“…Furthermore, the values of g s under W3, W4, and W5 in the morning were all lower than that at 1300 h. Li, Li, Li, and Zhang (2017) argued that the P n of drought‐tolerant wheat was restricted by the stomatal characteristics. Balla, Bencze, Bόnis, Árendás, and Veisc (2014) found that stomatal conductance was also limited by high temperature, drought, and their interaction that all affected photosynthetic efficiency of winter wheat.…”

Selection and Breeding of Suitable Crop Genotypes for Drought and Heat Periods in a Changing Climate: Which Morphological and Physiological Properties Should Be Considered?

“…The maturation of fruits and seeds under abiotic stresses is highly relevant for a series of the world most important crops including rice, wheat, maize and soybean [145][146][147][148]. The translocation of nutrients and assimilates via xylem and phloem to the reproductive structures ( Figure 2H), the remobilization of leaf constituents ( Figure 2K) and processes in the maturing fruits including the deposition of storage compounds in the seeds ( Figure 2N) are relevant in this context and depend on water availability [146][147][148] and ambient temperature [145,147,148].…”

“…The translocation of nutrients and assimilates via xylem and phloem to the reproductive structures ( Figure 2H), the remobilization of leaf constituents ( Figure 2K) and processes in the maturing fruits including the deposition of storage compounds in the seeds ( Figure 2N) are relevant in this context and depend on water availability [146][147][148] and ambient temperature [145,147,148]. Landraces with a high genetic diversity may serve as a helpful basis for breeding crop genotypes with suitable properties in the course of climate change (e.g., stable yields, high quality of harvested products) [148].…”

“…Landraces with a high genetic diversity may serve as a helpful basis for breeding crop genotypes with suitable properties in the course of climate change (e.g., stable yields, high quality of harvested products) [148]. Genetic variability in the response to abiotic stresses such as heat and drought were reported for several crop plants indicating that there might still be a potential for further breeding [146][147][148]. Since drought and heat occur often simultaneously, the combined effects of these abiotic stresses are of special relevance [147,148].…”