Effect of Soil Water Deficit on Growth and Development of Plants: A Review

Plants in nature are continuously exposed to several biotic and environmental limitations. Among these limitations, soil water deficit is one of the most adverse factors of plant growth and productivity and is considered a severe threat for sustainable crop production in the conditions of changing climate. Scarcity of water is a severe environmental constraint to plant productivity. Soil water deficit-induced loss in crop yield probably exceeds losses from all other causes, since both the severity and duration of the limitations are critical. Various management strategies have been proposed to cope with soil water deficit. Soil water deficit reduces leaf size, stem extension, and root proliferation, disturbs plant–water relations, and reduces water use efficiency. Plants display a variety of physiological and biochemical responses at cellular and whole-organism levels towards prevailing soil water deficit, thus making it a complex phenomenon. CO2 assimilation by leaves is reduced mainly by stomatal closure, membrane damage, and disturbed activity of various enzymes, especially those of CO2 fixation and adenosine triphosphate synthesis. Low molecular weight osmolytes, including glycine betaine, proline, and other amino acids, organic acids, and polyols are crucial to sustain cellular functions under soil water deficit. Plant growth substances such as salicylic acid, auxins, gibberellins, cytokinins, and abscisic acid modulate the plant responses towards soil water deficit. Polyamines, citrulline, and several enzymes act as antioxidants and reduce the adverse effects of water deficit. Soil water deficit is a multidimensional phenomenon affecting plants at various levels of their organization. The effect of and plant response to soil water deficit at the whole plant and crop level is most complex because it reflects the integration of these environmental limitation effects and responses at all underlying levels of organization over space and time.