Antioxidative Regulation of Root Elongation Restricted by Abiotic Stress

One of the most common plant responses to abiotic stresses, including drought, salinity, or heat stress is the over-production of reactive oxygen species (ROS), which causes oxidative damages to cellular constituents, such as proteins, DNA, and lipids, as well as the deterioration of cellular structures. Stress-inhibition of root growth, particularly root elongtaiton has been related to ROS accumulation. Root elongation or cell expansion is controlled by cell-wall loosening proteins, such as expansins and xyloglucan endotransglycosylases. Increasing research has shown the positive effects of growth-promoting hormones, such as cytokinins and antioxidant molecules, such as ascorbic acid alleviating stress-inhibition of root elongation, which has been associated with enhanced non-enzymatic ROS scavenging capacity and/or activation of antioxidant enzymatic defense systems, as well as up-regulating cell-wall loosening proteins. This presentation will discuss biochemical and molecular mechanisms of how mitigation of oxidative damages or ROS scavenging and interaction with cell-wall loosening properties by hormones and antioxidants help to maintain root growth or enhance root elongation for plants exposed to abiotic stresses.