Ecophysiological Responses of Rice (Oryza sativa L.) to Drought and High Temperature

Abstract

Global rice crop production is being threatened by a frequent rise in high temperatures and drought. Drought and heat stresses adversely affect the morphological, physiological, and biochemical characteristics of rice, resulting in reduced crop productivity. Heat and drought stresses entail physiological changes in rice plants, such as stomata closure, reduced photosynthesis, loss of turgor adjustment, and reduction in crop productivity. These stresses also cause metabolic changes by increasing the activities of antioxidative enzymes, phytohormones, abscisic acid, reactive oxygen species, and reactive stress metabolites. Among the different growth stages of rice, the reproductive stage is the most sensitive stage to high temperature and drought, resulting in low seed setting and grain yield. Genetic improvement and development of drought and heat-stress-tolerant rice varieties increase seed setting and enhance yield production even under stress conditions. Because of the multigenic nature of traits, the development of drought and high-temperature-tolerant varieties through genetic improvement is the best approach. Here, we summarized the effects of heat and drought stresses on the physiological traits of rice. We focused on different approaches to managing high-temperature and drought stresses, such as an adjustment in cultural practices, genetic improvement through molecular breeding, and the development of transgenics and chemical spray from an agricultural practice perspective.