Root Recovery Development and Activity of Cotton Plants after Waterlogging

Cotton (Gossypium hirsutum L.) yield is severely limited by waterlogging in some global production areas. The objective was to study physiological and biochemical mechanisms of cotton root recovery aft er waterlogging during different reproductive stages. Cotton plants (cultivar Simian 3) were subjected to waterlogging for 10 d and then permitted to recover for 20 d. Waterlogging significantly reduced root dry matter, root vigor, and net photosynthetic rate (P-n). Aft er the termination of waterlogging, root growth showed a significant recovery. Root dry matter of waterlogged plants increased quickly, but remained 20 to 30% lower than controls. Total N content in waterlogged cotton roots was the same as controls at 20 d aft er waterlogging during the squaring stage, but was significantly lower during the flowering and boll-forming stage. The activities of superoxide dismutase, catalase, and peroxidase in waterlogged plants increased for 10 d aft er waterlogging, then declined slowly. The malondialdehyde content in waterlogged roots continued to increase for 5 d aft er waterlogging, then declined to a significantly lower level than the control. Root vigor recovered rapidly aft er waterlogging, and was much higher than the control during the squaring stage, but significantly lower during flowering and boll-forming stage. P-n of waterlogged cotton was suppressed aft er a 10-d recovery period, and remained lower than well-watered controls. These results suggest (i) roots of waterlogged cotton recovered more quickly than shoots, (ii) cotton roots recover better from oxidant damage due to waterlogging during the squaring stage than during the flowering and boll-forming stage.