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Byline: Syeda Anum Masood Bokhari, Ayesha Sameen, Muhammad Awais Rana and Syed Haroon Masood Bokhari

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 world's 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, tissue's 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.

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Author:Anum, Syeda; Bokhari, Masood; Sameen, Ayesha; Rana, Muhammad Awais; Haroon, Syed; Bokhari, Haroon Ma
Publication:Technology Times
Geographic Code:9PAKI
Date:Jul 24, 2016

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