Study On The Recovery Of Growth And Its Physiological Mechanisim Of Cotton After Waterlogging During The Bud Stage And Flowering And Boll-Forming Stage

Flourishing bud stage and flowering and boll-forming stage is the key period for nutritional growth and cotton yield and quality. Waterlogging during the two stages significantly inhibits cotton development and reduces final productivity and fiber quality. The growth and physiological characteristics of cotton were badly damaged under waterlogging, but some of them could recover after waterlogging. The study on the recovery growth and its physiological mechanism for cotton yield formation after waterlogging has obvious implication for improving waterlogging resistance and guiding cultural management in cotton. Experiment was conducted during flourishing bud stage and flowering and boll-forming stage and cotton were subjected to waterlogging for ten days and then permitting to twenty days recover. The study focused on:(1) recovery effects on the growth and yield of cotton after waterlogging during;(2) recovery growth and physiological mechanism on cotton root after waterlogging;(3) recovery growth and physiological mechanism on cotton leaf after waterlogging; The main results were as follows:1. Recovery effects on the growth and yield of cotton after waterloggingWaterlogging significantly decreased the dry weight and nitrogen accumulation of cotton root and leaf during the two stages. The nitrogen accumulation of all organizations decreased in the flowering and boll-forming stage. The recovery rate of dry weight in flourishing bud stage was faster than that in flowering and boll-forming stage after waterlogging. Waterlogging increased the nitrogen distributive indices of root and stem and branch which did not change significantly. The yield of prophase decreased much more than later period and fruit nodes and the rate of boll-forming decreased significantly, but all of them recovered much more faster than that in flowering and boll-forming stage. 2. Recovery recovery growth and physiological mechanism on cotton root after waterloggingWaterlogging significantly decreased the root dry matter weight and the Root/Shoot ratio and root vigor. After waterlogging, the rate of recovery growth on root dry matter weight and root vigor in flourishing bud stage was faster than that in flowering and boll-forming stage. The nitrogen and soluble protein content increased significantly after waterlogging in flourishing bud stage, and the content of them could reach to the control in the twentieth day after waterlogging, but that in flowering and boll-forming stage showed the opposite results. The activities of superoxide dismutase, peroxidase and catalase of cotton roots in flourishing bud stage were higher than that in flowering and boll-forming stage. The content of IAA, GA and ZR significantly increased after waterlogging during the two stages and them remained higher in the fifteenth day during flourishing bud stage. May be lots of adventitious root emerged during the flourishing bud stage.3. Recovery recovery growth and physiological mechanism on cotton leaf after waterloggingThere types of cotton leaves which at function stage(T1), fast developing stage(T2) and flat stage(T3) were marked before water logging.Beside comparing the changes of chlorophyll content and nitrate reductase activity of the leaves, the nitrogen content, soluble sugar and leaf area of plant leaves in 20 days were investigated after treatment to illustrate the recovery effects of physiological and agronomy character. The result showed that nitrate reductase activity in there type leaves was recovered after stress released. The total chlorophyll content of leaves treated at function stage(T1) can't rise up to that of control, while that of leaves treated at fast developing stage(T2) and leaves treated at flat stage(T3) was increased significantly after stress released. The nitrogen content of plant leaves was increased after terminating water logging in flourishing bud stage but it was markedly lower than that of control in flowering and boll-forming stage. Soluble sugar content was increased significantly after water logging treatment in flourishing bud stage and then decreased to that of control after treatment released, while it showed little difference in flowering and boll-forming stage. Leaf area was reduced after water logging and recovered after treatment released, but it can't be recovered as control. It is concluded that tender leaves recovered fast than others and the recoverability in flourishing bud was higher than that in flowering and boll-forming stage.