In the current century, global warming is becoming an alarming issue causing an increase in the area of barren lands. Arid and semi-arid regions are characterised with shortage of water in both under- and above-ground environments. Plants with high water use efficiency should be considered for cultivation in those regions. Water loss is needed for cooling plant and absorbing minerals, however, excessive water loss can result in wilting. Plants control the water loss through adjusting the volume of stomatal guard cells and fine tuning the movements of stomata. Fine tune-functioning of stomata can help the plants to cope with drought conditions. Vapour pressure difference (VPD) between stomatal cavity and surrounding environment determines the water status of the leaf. In the short term, stomata respond in a regular way to VPD. However, when plants are exposed for a long term to conditions triggering stomatal opening (such as low VPD, prolonged lighting duration and air pollutants), the behaviour of the stomata in response to drought stress changes and the stomata are incapable of suitable response to closing stimuli (stomatal malfunctioning). Finding the reasons for occurrence of stomatal malfunctioning can help us to improve plant acclimation to dried environments. Exploring genetic variation in stomatal response among naturally occurring populations is the first step to figure out the mechanism controlling stomatal movements in different environments.