Research On The Mechanism Of Chitosan Oligosaccharide Improving The Quality And Drought Resistance Of Brassica Chinensis L.Var.Parachinnen

Based on biological activity of chitosan oligosaccharide that it could induce plant defense responses, improve plant yield and quality of horticultural products, prevente disease, multiply beneficial bacteria in the biologic fertilizer and soil, have the character of pesticides and fertilizer and so on, taking "Youqing26" and "sweet Brassica chinensis31" as experimental materials, the effects of chitosan oligosaccharide on the Brassica chinensis yieid、quality and drought resistance were studied, in order to provide theoretical basis for healthy vegetable product growing and improving plant drought resistance.The main results were summarized as follows:1.Efect of different concentration chitosan oligosaccharide on yield and quality of Brassica chinensis:At the extent of0-100μg/mL chitosan oligosaccharide, the height、 stem、length and width of leaf、grain weight per plan、content of dry matter、 chlorophyll、soluble sugar、soluble protein、vitamin C and free amino acid first increased and then drop following the concentration increased, but the content of nitrate changed oppositely. The result of spraying of50μg/mL chitosan oligosaccharide on "Youqing26" was best, while the most significant result of "Sweet Brassica chinensis31" was25μg/mL treatment. Consequently, the best spraying stage was early growth stage and the best spraying concentration was25-50μg/mL.2. Effects of different spraying time concentration chitosan oligosaccharide on yield and quality of Brassica chinensis:At the stages that before3days of transplanting、four leaves stage and eight leaves stage, the significant spraying result of "Youqing26" were before3days of transplanting and the stage of eight leaves, the best result of "Sweet Brassica chinensis31" was four leaves stage. Consequently, the best spraying stage was seedling stage.3. Effects of Brassica chinensis drought resistance on Haidaosu:Low concentration treatment could inhibit producing MDA, improve the activity of CAT、POD、SOD, increase the content of soluble sugar and proline and alleviate the hydrolyzation of soluble protein. The best concentration spraying concentration of different varieties was different. The best spraying concentration of "youqing26" was50μg/mL, however, the best spraying concentration of "sweet Brassica chinensis31" was25μg/mL.