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Due to anthropogenic as well as by natural factors the climate of earth is predicted to be warm by an average of 2-4 °C, at the end of the 21st Century. Emission of green house gases (GHG) from agricultural system is one of the major contributing factor in global warming. Heat stress is one of the major abiotic stresses threatening plant growth worldwide. Agricultural crops suffer in presenting their optimum yield potential due to heat stress. Heat stress causes enormous alterations in various processes within the plant system; most of them are well understood from various physiological, biochemical and molecular studies. Heat stress not only affects the morphological and phenological parameters but also the physiological and biochemical parameters like plant water relationship, photosynthesis, assimilate partitioning, hormonal changes, cell membrane stability, production of secondary plant metabolites, antioxidative metabolism, synthesis of heat shock proteins, cell signalling etc. In the advent of climate change and subsequent global warming there is an urgent need for understanding the physiological and biochemical basis of heat stress tolerance in crop plants. There has been a lot of effort worldwide in this regard to develop high temperature tolerant genotypes through transgenic intervention and genetic engineering. This paper reviews the literature supporting evidence for the morphological, phenological, physiological and biochemical effects of heat stress on several plants and different molecular approaches to develop transgenics tolerant to high temperature stress. A plethora of these kinds of plant responses are finally regulated by the genes. Hence, more biotechnological and molecular studies including genomics, proteomics, metaboliomics and the cryptomics are necessary to elucidate the processes further. [ABSTRACT FROM AUTHOR]

Sulfur is a growth-limiting and secondary macronutrient as well as an indispensable component for several cellular components of crop plants. Over the years various scientists have conducted several experiments on sulfur metabolism based on different aspects of plants. Sulfur metabolism in seeds has immense importance in terms of the different sulfur-containing seed storage proteins, the significance of transporters in seeds, the role of sulfur during the time of seed germination, etc. The present review article is based on an overview of sulfur metabolism in seeds, in respect to source to sink relationships, S transporters present in the seeds, S-regulated seed storage proteins and the importance of sulfur at the time of seed germination. Sulfur is an essential component and a decidable factor for seed yield and the quality of seeds in terms of oil content in oilseeds, storage of qualitative proteins in legumes and has a significant role in carbohydrate metabolism in cereals. In conclusion, a few future perspectives towards a more comprehensive knowledge on S metabolism/mechanism during seed development, storage and germination have also been stated. [ABSTRACT FROM AUTHOR]

• Heat stress in plants causes several morphological, physiological and molecular changes affecting growth and yield attributes. • Seed priming is an eco-friendly technology to induce uniform and rapid emergence of seed that leads to better stand establishment and improvement in yield, under both optimal and adverse environments. • Nitrate priming of seeds improves seed germination, crop growth, nitrogen metabolism and increases nitrate reductase activity, enabling reversal of heat stress induced responses in plants, maintaining the yield potential of the plants. Exhaustion of natural sources due to expanding usage leads to an increase in global temperature. Heat stress and rising CO 2 severely impact crop growth and catastrophic loss of agriculture ecosystem, productivity and quality. The physiological and metabolic processes of plants are affected by heat stress due to denatured proteins, lipid structure, alteration in membrane integrity and inactivation of enzymes incurred at various growth stages. To diminish heat stress losses in plants, many techniques such as conventional breeding, genetic engineering, molecular breeding were used by the agriculturists, which helped develop tolerant varieties of crops with increased quality and production. Recent advancement in seed priming has many fold impacts such as mitigation of stress via improving tolerance mechanisms in plants, reduction in soil and water pollution, improved production and food quality of important agriculture crops. It is one of the low-cost, reliable and profitable crop improvement techniques. Nitrates have several roles in modulating the plant processes. Priming with nitrate salts improves nitrate reductase and amylase activity, nitrogen, amino acid and chlorophyll content in leaves, causes increase in proline, sugar content, antioxidant metabolism, grain yield, protein and nutrient content in various crops. Despite positive responses of nitrate seed priming, this technology has been less applied in the area of crop production in the field condition. Considering these facts, this review depicts responses of the plants under heat stress and their management through nitrate seed priming. [ABSTRACT FROM AUTHOR]