Plant Responses to Drought Stress: Physiological, Biochemical and Molecular Basis

Drought is one of the most serious threats to crop production all over the world and is likely to worsen with anticipated changes in the climate. Drought impairs normal growth, disturbs water relations and reduces water-use efficiency in plants. Plants, however, have a variety of physiological and biochemical responses at cellular and organism levels, making it a more complex phenomenon. Researchers have been trying to understand and dissect the mechanisms of plant tolerance to drought stress using various approaches. The present chapter describes the strategies used by plants to adapt to low water potential at physiological, biochemical and molecular levels. This chapter also describes the strategies involving genetic engineering used by breeders in order to obtain crop varieties with improved drought tolerance, some of which show great promise. Modern genomic and genetic approaches coupled with breeding methodologies are expected to more effectively identify the genes and metabolic pathways that confer drought tolerance in crops.