RESUMO
Drought stress is one of the major abiotic stress that can causes huge loss to the world food production. It remains a major contributor to severe food shortage and famine. With a consistent increase in world population, pressure will continue to mount on the existing yet limited water resources. The situation is respected to further aggravate due to the predicted increase in temperature and decrease in precipitation consequent upon global warming. Water scarcity has already become a severe constraint in plant survival and productivity of crops in arid and semi-arid regions. The active response of plants to drought stress through various biochemical and physiological modifications improves the metabolism and can further the mobilize various defense mechanisms in order to enhance survival of the plants under conditions of drought. In this review, various physiological and biochemical responses in plants towards enhancement of drought tolerance are discussed.