The Applications to Increase Drought Tolerance of Plants

Abstract

Terminal drought is a major threat that adversely affects crop growth and metabolism, and limits the yield. Water stress causes many morphological, physiological and biochemical changes in plants. Plant height, root length, leaf area, fresh and dry biomass are reduced under drought stress. Besides, water stress causes the reduction of relative water content, the closure of stomata and decrease in photosynthesis and chlorophyll content. Antioxidant enzymes such as glutathione reductase (GR), superoxide dismutase (SOD), peroxidase (POD), ascorbat peroxidase (ASC), glutatiton (GSH), catalase (CAT) enzyme activities, the indicator of oxidative stress malondialdehyde (MDA) and proline levels also changes in drought conditions. Nutrient uptake by plants is prevented or restricted before grain development stage during drought conditions. Therefore the application of plant nutrients followed by micronutrient remobilization within plant is great importance. Osmoprotectants (cytokinin, mannitol, abscisic acid, proline, glycine betaine, polyamine etc.) detoxify adverse effect of reactive oxygen species (ROS) and alleviate drought stress. Exogenous plant growth promoting rhizobacteria (PGPR) application encourage plant growth by colonizing the plant root and increase plants’ resistance to water stress. Besides, the farmers can use conservation tillage system in dry periods.