Abstract

Environmental stresses cause a wide range of reactions such as changes in gene expression, changes in cell metabolism, changes in function and growth rate. Among environmental stresses, drought stress is the most critical ecological constraint that affects productivity and product quality and limits plant growth at different stages such as germination, seedling establishment, etc. Wheat is the third-largest producer in the world after corn and rice. In nature, after cellulose, starch is the most important known organic compound. The functional behavior of starch is complexly related to its structure and morphology. Various experiments have shown that starch biosynthesis and accumulation are affected by external environmental factors such as drought. Due to the interference of physiological and biochemical processes of starch producing and storing cells, drought stress accelerates the onset and filling time of the grain and reduces the accumulation of starch, which changes the productivity of wheat production. Soil dryness affects starch synthesis by regulating starch biosynthesis enzymes. Drought also reduces the content of amylose, fat, grain size and increases the peak viscosity and final viscosity of the starch. Investigation of morphological and physicochemical properties of starch granules in wheat varieties under drought stress, can provide insight into the mechanisms and regulation of wheat starch biosynthesis and provide potentially helpful information for growing drought-resistant wheat varieties with good starch properties and high yield potential.