الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Drought is one of the most common abiotic factors which harmed growth and development of plant, and is becoming an increasingly severe problem in many regions of the world (Zalibekov, 2011; Hossain et al., 2013; Lipiec et al., 2013). Extreme water shortage causes considerable physiological, metabolic and morphological changes in plant, and ultimately reduces crop yield and quality (Maqsood et al., 2012). Many regions of the Earth are often or permanently exposed to drought (Bray, 1997). Tas and Tas (2007) have defined drought as one of the environmental stresses, which is the most significant factor restricting plant growth and crop productivity in the majority of agricultural fields of the world. A great deal of researches has been carried out on physiological, biochemical and molecular responses of various plants to conditions of drought. In general, drought is responsible for several metabolic processes of plants, with photosynthetic apparatus being one of the most important (Nayyar and Gupta, 2006). Besides changes in photosynthesis, such adverse effects on metabolism lead to growth inhibition, stomata closure with consecutive reduction of transpiration, which are considered necessary for coping with osmotic changes in their tissues (Lawlor and Cornic, 2002; Zhu, 2002; Yordanov et al., 2003). Water stress leads to the formation of ROS, which are extremely harmful to the plants. Riccardi et al. (2004) have demonstrated that plant response to water deficit shows some genetic variations.