Study On Physiological Response On Cucumber Seedlings Under Nitrate And Suboptimal Temperature Stress And Mitigation Effects Of Iron-chlorophyllin

Cucumber (Cucumis sativus L.) is widely planted in facilities, cold sensitive, enjoy light, roots distribute shallowly, enjoy fertilizer but fertilizer intolerance. Soil secondary salinization in protected cultivation is one of the major soil barrier factors which are seriously restricting the high yield and good quality of vegetable crops in greenhouse.The long-term cultivation environment contributes appears in winter and earlier spring also affects the development of the cucumber yield and quality.In this research, effects of exogenous iron chlorophyllin on cucumber seedlings growth and physiological characteristics under nitrate and suboptimal temperature stress were studied.In order to provide new method in reducing the secondary salinization of soid damage and improving suboptimal temperature adaptability.Based on the previous experimental research, effects of exogenous iron chlorophyllin on cucumber seedlings plant height, leaf area, fresh and dry weight, osmotic adjustment sub-stances, nitrogen metabolism and anti-oxidation enzyme system were studied under nitrate and suboptimal temperature stress. The major results are summarized as follows:1. When subject to7days of NO3-stress, spraying of10mg-L-1iron chlorophyllin treatment increased the fresh and dry weight, plant height, leaf area and root activity. This shows that10mg-L-1iron chlorophyllin significantly enhanced resistance to NO3-stress of cucumber seedling.The result shows that foliar-spraying appropriate concentration of iron chlorophyllin could reduce the damage and promote growth of cucumber seedlings in various degree under NO3-stress.2. After5and10days of NO3-stress, spraying of10mg-L-1iron chlorophyllin significantly decreased the electrolyte leakage rate, MDA, proline,souble sugar, NO3--N and NH4+-N contents,and significantly incressed souble protein contents and NR、GS、GDH and GOGAT activities and antioxidant enzyme activity. The result shows that spraying of10mg-L-1iron chlorophyllin could reduce membrane lipid peroxidation and permeability damage, enhance the metabolism of nitrogen and reduce the accumulation of nitrogen NO3--N and NH4+-N.3. Under suboptimal temperature, spraying of5mg-L-1iron chlorophyllin increased the fresh and dry weight, plant height, leaf area and NR activity after7days. This shows that10mg-L-1iron chlorophyllin significantly enhanced resistance to suboptimal temperature of cucumber seedling. The result shows that foliar-spraying appropriate concentration of iron chlorophyllin could reduce the damage and promote growth of cucumber seedlings in various degree under suboptimal temperature. 4. After5and10days of suboptimal temperature, spraying of5mg-L-1iron chlorophyllin significantly decreased the electrolyte leakage rate and MDA, NO3--N and NH4+-N con-tents, and significantly incressed proline,souble sugar, souble protein contents,and NR、 GS、GDH and GOGAT activities and antioxidant enzyme activity. The result shows that spraying of5mg-L-1iron chlorophyllin could reduce membrane lipid peroxidation and permeability damage, enhance the metabolism of nitrogen and reduce the accumulation of nitrogen NO3--N and NH4+-N,and improved adaptability to suboptimal temperature of cu-cumber seedlings.