Heat Stress Responses and Thermotolerance

Abstract

climate change is that most agricultural regions will experience additional extreme environmental fluctuations [2]. Direct injuries due to high temperatures include protein denaturation and aggregation and increased fluidity of membrane lipids. Indirect or slower heat injuries include inactivation of enzymes in chloroplast and mitochondria, inhibition of protein synthesis, protein degradation and loss of membrane integrity [3]. Heat stress also affects the organization of microtubules by splitting and/or elongation of spindles, formation of microtubule asters in mitotic cells and elongation of phragmoplast microtubules [4].The unfavourable effects of heat stress can be mitigated by developing crop plants with improved thermotolerance using an assortment of genetic approaches. For this reason, a thorough understanding of physiological responses of plants to high temperature, mechanisms of heat tolerance and possible strategies for improving crop thermotolerance is crucial. Acquiring thermotolerance is a lively progression by which considerable amounts of plant resources are diverted to structural and functional maintenance to escape damages caused by heat stress. Although biochemical and molecular aspects of thermotolerance in plants are relatively well understood, additional studies focused on phenotypic flexibility and assimilate partitioning under heat stress and factors modulating crop heat tolerance are imperative. High temperature during seed germination may slow down or totally inhibit germination, depending on plant species and the intensity of the stress [5]. At later stages, high IntroductionFuture global climate change, with predicted 1.5-5.8 °C increases in temperatures by 2100 has to cause heat stress to create threats to agricultural production [1]. An increase in global temperature ranging from 1.1 to 6.4 °C depending on global emissions scenarios, will accompany the rises in atmospheric CO 2 . Though high temperature and other abiotic stresses are clearly limiting factors for crops cultivated on marginal lands, crop productivity far and wide is often at the mercy of random environmental fluctuations. Existing assumption about global Heat Stress Responses and Thermotolerance AbstractThe rising ambient temperature by plant cells is crucial for the timely activation of various molecular defences before the appearance of heat damage. The heat-threshold level varies considerably at different developmental stages. With a view to survive under heat stress, mechanisms of regulation at the molecular level enable plants to prosper. Traditional breeding contributed for improving heat tolerance meagrely. The genetic transformation approach needs to be accelerated that can mitigate harmful effects by developing improved thermotolerance of crop plants. In this background, a thorough understanding of physiological responses of plants to high temperature, mechanisms of heat tolerance and possible strategies is vital. Temperature changes are sensed through cellular responses due to signal transduction into the c...

Performance and Stability of Commercial Wheat Cultivars under Terminal Heat Stress

“…Heat stress (late sown condition) increased average canopy temperature across all cultivars. The correlation between canopy temperature and grain yield was negative and significant which agrees with previously reported results [49][50][51]. The prevalence and severity of stem and leaf rust were increased due to the late sown condition.…”

Biochemical and molecular responses of herbaceous peony to high temperature stress

“…As one of the most important environmental factors affecting plant growth and development, the subtle changes in temperatures might have some adverse impacts on plants, including morphological, physiological, biochemical and molecular changes, especially at high temperatures that occur in the summer (Bita and Gerats 2013). For example, high temperatures can cause the growth inhibition of shoot and root, scorching of leaves and stems, leaf senescence and abscission, as well as a decrease in crop yields (Teixeira et al 2013;Hemantaranjan et al 2014). Therefore, studying plant tolerance to high temperatures has attracted the attention of many researchers.…”

Influence of High Temperature on Photosynthesis, Antioxidative Capacity of Chloroplast, and Carbon Assimilation among Heat-tolerant and Heat-susceptible Genotypes of Nonheading Chinese Cabbage

“…The photosynthesis in C 3 plant is more sensitive to HT, especially the photo-synthetic apparatus (Wahid and Rasul, 2005). HT differently affects the stability of many proteins and membrane system and alters the efficiency of enzymatic reactions in the cell (Hemantaranjan et al, 2014). Diminished photosynthetic capacity is a primary damage effect by HT.…”