ABSTRACT
Drought stress is one of the major abiotic stresses limiting plant growth and productivity [1,2]. It will continue to be a serious problem in agriculture because water is becoming more limited due to increased use by the expanding human population, decreasing precipitation, and lower potable water availability. Extensive research efforts have been taken to investigate mechanisms that impart drought tolerance of various plant species. During the process of plant adaptation to drought stress, plants have developed sophisticated systems to avoid, tolerate, or escape drought stress. Various physiological, biochemical, and molecular processes change in response to drought stress, which determine the survivability and persistence of plants in water-limiting environments. One of the important strategies of plant adaptation to drought stress is water conservation. This could be achieved by rapid stomatal closure, resulting in the reduction of water loss through transpiration. The question
of how plants detect drought stress and close stomata during drought stress has received increasing attention during the last few decades [3-5].
