Morpho-physiological and biochemical response of rice (Oryza sativa L.) to drought stress: A review

Global food shortages are caused mainly by drought, the primary driver of yield loss in agriculture worldwide. Drought stress negatively impacts the physiological and morphological characteristics of rice (Oryza sativa L.), limiting the plant productivity and hence the economy of global rice production. Physiological changes due to drought stress in rice include constrained cell division and elongation, stomatal closure, loss of turgor adjustment, reduced photosynthesis, and lower yields. Morphological changes include inhibition of seed germination, reduced tillers, early maturity, and reduced biomass. In addition, drought stress leads to a metabolic alteration by increasing the buildup of reactive oxygen species, reactive stress metabolites, antioxidative enzymes, and abscisic acid. Rice tends to combat drought through three major phenomena; tolerance, avoidance, and escape. Several mitigation techniques are introduced and adapted to combat drought stress which includes choosing drought-tolerant cultivars, planting early types, maintaining adequate moisture levels, conventional breeding, molecular maintenance, and creating variants with high-yielding characteristics. This review attempts to evaluate the various morpho-physiological responses of the rice plant to drought, along with drought stress reduction techniques.