Biochemical and Physiological Responses of Thermostable Wheat Genotypes for Agronomic Yield under Heat Stress during Reproductive Stages

Abstract

Wheat is a globally important crop used as a main staple food in various countries of the world. The current study was conducted with the objective to evaluate the effect of a high temperature (HT) on osmolytes (starch, sucrose, total soluble sugars, total soluble proteins and proline), physiological parameters (Chl-a, Chl-b, photosynthesis rate, transpiration rate and stomatal conductance), antioxidant enzymes (superoxide dismutase, catalase and peroxidase) and agronomic traits (flag leaf area, spike length, and thousand grain weight) during the grain filling and anthesis stages of wheat cultivars (Fakhr-e-Bhakar, Raj-3765, Jimai-22 and Bayraktar-2000) collected from different regions of the world. Separate experiments for both stages were conducted in a glasshouse and treated with two different temperature regimes, i.e., optimum (OT) (24 °C day; 14 °C night) and high temperature (HT) (32 °C day; 22 °C night) in RCBD for two weeks. The data for osmolytes, antioxidant enzymes and physiological contents were collected at days 3, 5, 7, 9 and 13 after the start of plant stress, while the agronomic traits were collected at maturity. The data obtained were subjected to a statistical analysis using the statistix8.1 and R-program. HT stress significantly reduced all the traits except for the membrane damage, transpiration rate, proline and total soluble sugars, whose values increased considerably in the genotype Bayraktar-2000. However, under both regimes of temperature Fakhr-e-Bhakkar showed a high tolerance against HT stress, as revealed by physiological, biochemical and agronomic evaluations. Moreover, correlation, PCA and heat map analyses indicated that all types of traits are significantly interconnected in determining the crop potential to sustain its growth under HT stress.

Physiomorphic and molecular-based evaluation of wheat germplasm under drought and heat stress

“…In addition, both drought and heat stress imbalance osmolyte concentration, disturb physiological processes, and affect morphological and yield parameters such as flag leaf area (FLA), spike length, and grain weight ( Chaudhary et al., 2020 ; Pandey et al., 2022 ). Moreover, drought and heat stress decrease chlorophyll content and overall photosynthetic productivity, increase leaf senescence, promote carbohydrate mobilization to the stem, and reduce the grain-filling duration, resulting in stem weight loss in addition to a decline in grain number per spike, grain weight, straw yield, and harvest index ( Sarto et al., 2017 ; Alghabari et al., 2021 ).…”

Simultaneously evaluation of physiological and biochemical responses in the leaves and roots of Iranian common bermudagrass [Cynodon dactylon L. (Pers.)] accessions under a wide range of temperature fluctuations

“…This may be due to either decreased biosynthesis of chlorophyll, or enhanced degradation, or a combined effect of both. In addition, damage of the thylakoid membranes due to heat stress can cause more chlorophyll reduction 40 . Heat-induced reduction of chlorophyll and deactivation of rubisco and rubisco binding proteins reduce photosynthesis and consequently reduce plant growth 41 .…”

Physiological, biochemical and molecular evaluation of mungbean genotypes for agronomical yield under drought and salinity stresses in the presence of humic acid

“…Humic acid significantly countered the deleterious effects of drought and salinity and improved mungbean agronomic production by optimizing various physiological and genetic responses. Abiotic stresses impair crop productivity by hampering the physiological processes including Pn and Gs due to damage of cell membrane and photosystems ( Alghabari et al, 2021 ). Likewise, drought negatively affects Pn due to reduction in leaf area and damage of photosynthetic machinery including total chlorophyll content ( Bangar et al, 2019 ).…”

“…Furthermore total chlorophyll (total chl) was recorded following the method opted by Mahmood et al (2016) . Cell membrane damage (MD) percentage was calculated following the methodology used by Alghabari et al (2021) . In this perspective 100 mg leaf pieces were taken in two different tubes each with 20 mL deionized water.…”