Using Plant Growth Regulators To Mitigate Cotton Damage After Waterlogging

Water is the source of our lives. The assurance of the demand of water for crop timely and effectively is a crucial link in agricultural production activities. However, it is not good for the normal growth of crop when the water is too much or too little. Waterlogged disaster, the important limiting factor for restricting crop growth, is the second climatic disaster except drought. It usually appears every five years and the high frequency of occurrence occurs at the middle and lower reaches of Yangtze River in summer. According to statistics, during the month of March to September in Jianghan plain region, the occurrence frequency of waterlogged disaster is from75.47to83.78. The farmland,which is easily waterlogging and soiled, are distributed extensively in southeast coast and middle and lower reaches of Yangtze River in China. There are7.64million hm2waterlogging and soiled farmland in Jianghan plain, which occupy40.6%of the total area of the farmland. Waterlogged disaster is the main factor to limit the sustainable development of agriculture. Cotton is widely cultivated in the Jianghan plain and is one of the most important economic crops, with the characteristics of liking sunlight, afraid of rain and avoiding of waterlogged. The whole period of duration of cotton is across the rainy season and the growth stage is during the concentrated-rain period of Jianghan plain. Therefore, the waterlogged disaster is existed objectively and affects the production and quality of cotton.According to the typical waterlogged disaster characteristics of Jianghan plain, and sums up the waterlogged stress on cotton agronomic traits and physiological character and the influence of the economic characters. Because of farmland moisture damage in waterlogged disaster mainly has enormous influence on the cotton crop, the high yield and instability of crops lie in the stains and waterlogging,thus carrying out easily soiled areas liable to waterlogging prevention waterlogged disaster research, to promote the agricultural development has important practical significance.Therefore, actively carrying on the prevention and control of cotton waterlogged, to ensure crop yield and quality and the farmers’income is of great significance.At present, the existing relevant research proves that the use of plant growth regulator, such as:polyamine, salicylic acid, PP333, BR-120, ethylene on plant growth, development and play an important role in regulating metabolism, can effectively alleviate waterlogged disaster and promote restoration of the plant physiology, but single use effect is limited, and can not easy control, although has the function of the plants, but the performance on the yield characters often is not stable. In addition, studies have proved that by fertilizing method can effectively promote the recovery after waterlogging for plants to grow.Utilize the integrated use of plant growth regulating substances and fertilizer and comparing crops after waterlogging on the shape of physiological characteristics and yield of the differences of nutritional regulation and chemical regulation to find out the best combination, and the best time to spraying.Respectively on the three different stages:cotton seedling stage, bud stage, and the blooming period of growth, physiological activity and the influence of the late production, and through application of comprehensive nutrition regulation and chemical regulation role in relieving Wet injury on cotton growth and mechanism of action, to improve the cultivation of resilience, speed up the recovery cotton waterlogging and promote cotton output to provide certain theoretical basis.The main results are staded as below:1.Waterlogging stress effect on the growth of cotton in seedling stage and repair technology.Results show that the crop under waterlogging stress conditions, the chlorophyll fluorescence parameters and chlorophyll content has been a downward trend, affected the photosynthesis, cotton eventually affected cotton production.Wet injury stress on the number of leave of cotton in seedling stage had no significant effect.The content of malondialdehyde (MDA) with the extension of waterlogging water time increased, cell membrane injury degree increasing, affecting the cotton leaf cell activity.The research results show that the flood of cotton after applying Z regulator can significantly increase the cotton plant height, chlorophyll content and chlorophyll fluorescence parameters and reduce MDA content rapidly,make The bud on summer and The bud on autumn of the cotton number improve and the final output, Sprayingplant growth regulator which contain spraying abscisic acid (ABA), the regulator repair effect is the most prominent aspects of cotton, this may and abscisic acid can improve plant some features of physiological activities.2.Waterlogging was studied in the effect of stress on stage of cotton growth and repair technology.Results show that the crops in different depth of waterlogging stress, the decrease in chlorophyll content and chlorophyll fluorescence parameters, with the20cm deep submergence in cotton in chlorophyll content and chlorophyll fluorescence parameters decreased significantly compared with cotton flooded deep at15cm,Malondialdehyde (MDA) content in different depth under waterlogging stress, with the20cm deep submergence in cotton is higher than flooded deep cotton at15cm;The research results show that cotton level of stress is related to submergence depth, the depth is more deep, waterlogging stress is more heavy;Waterlogging after applying regulator can alleviate wet injury harm to crops, increase crop resistance of various aspects, including two kinds of different plant growth regulator (canola, lactone and phenol) sodium nitrate in chlorophyll content and chlorophyll fluorescence parameters and slows the POD activity and MDA content and increase the output of final effect difference.3.Waterlogging stress is studied in bell period of cotton growth and repair technology.Results show that the crop under waterlogging stress conditions, photosynthetic capacity decreased, the plant cell membrane was damaged, cell enzyme activity;wet injury stress on the seedling of cotton leaf number of how many had no significant effect.The research results show that spraying with fertilizer regulator is significant to the crop stresses ability;By3days during the elimination and start the processing of spraying regulator in MDA content, chlorophyll fluorescence parameters and chlorophyll content of5days start spraying regulator and waterlogging treatment difference is not obvious; The waterlogging spraying on the end of the day to adjust processing MDA content, chlorophyll fluorescence parameters and chlorophyll content under waterlogging spraying regulator3days after processing; Cotton waterlogging after spraying regulator can effectively increase the yield.