Climatic changes and global warming are the major issues of 21 st century. Plants are consistently

exposed to biotic and abiotic stresses. Harmful effects resultant from global climate changes

possibly impart losses in crop productivity. Among abiotic stresses, drought is pondered as the

single most caustic environmental stress, which not only affects the plant growth and

development but also decreases the crop productivity.

A continuous deficit in rainfall combined with higher evapotranspiration demand points towards the agricultural drought.

Agricultural drought is the shortage of sufficient moisture necessary for the normal development

and growth of plants to complete its life cycle. It mainly focuses on precipitation shortages, soil

water deficits and reduced ground water, these all factors mutually results in water stress to

plant. Water is the most important aspect for the proper plant growth because under drought

condition plants fail to perform their normal growth activities which causes major threat to plant

cultivation. About 40 to 60 percent worlds agriculture land has been effected by drought.

Drought stress is affected by climatic, edaphic and agronomic factors. The susceptibility of

plants to drought stress varies independence of stress degree, different accompanying stress

factors, plant species, and their developmental stages. Acclimation of plants to water deficit is

the result of different events, which lead to adaptive changes in plant growth and physio-

biochemical processes, such as changes in plant structure, growth rate, tissues osmotic potential

and antioxidant defenses.

Drought badly affects the plant growth and development with considerable reductions in biomass

accumulation and growth rate in crops. The main concomitants of drought in crop plants are

reduced rate of stem elongation and root proliferation, cell division and enlargement, leaf size

and disturbed plant water and nutrient relations and stomatal fluctuations with reduced crop

productivity and water use efficiency (WUE).

Water deficit accelerates the biosynthesis of abscisic acid (ABA) which decreases the stomatal

conductance to lessen the transpirational losses. To cope with such challenges, it is essential to

comprehend the effects of drought on plants and morphological and physiological adaptations.

Several climate models have anticipated the increased severity and regularity of drought under

the continuing universal climate change circumstances. Therefore, it has become imperative to

explain the responses and adaptation of crops to water deficit, and take actions to improve the

drought resistance ability of crop plants and to ensure higher crop yields against unfavorable

environmental stresses. The drought resistant varieties and newly planned irrigation programs are

also required to compete with increasing water shortage conditions worldwide.

By Web Team

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