The Response Study Of Three Kinds Of Exognous Substances On Syringa Under Flooding Stress

Syringa is commonly used as garden greening tree speciesin the north of China.Despite Syringa has a strong adaptality to varieties of environmental stress,it is vulnerable to the waterlogging.In this study,ues the "3414" model of sodium nitroprusside,spermiden and epibrassinolide on Syringa oblate and Syringa microphylla under flooding stress to test the photosynthetic rate, chlorophyll and physiological indicators, analyze and compare different treatment to alleviate the effect of water stress, identify the most appropriate ratio.1. The leaves of Syringa turn yellow and wilting,eventually fall of under flooding stress. Exogenous spraying SNP, Spd and EBR can significantly slow the leaves turn yellow, delay the leaves wilting time, extend the survival time of Syringa under stress. The net photosynthetic rate and chlorophyll degradation of Syringa are decreased under flooding stress. SNP, Spd and EBR three factors work together would increase the net photosynthetic rate to the control and ease chlorophyll content.From the regression model, Syringa oblata in SNP, Spd and EBR best surueyed which is 0.13mmol·L-1,0.2mmol·L-1 and 0.75mg·L-1.Syringa microphylla in SNP, Spd and EBR best surueyed which is 0.17mmol·L-1,0.36mmol·L-1 and 0.68mg·L-1.Chlorophyll content of Syringa oblate is the hightest in SNP, Spd and EBR surueyed which respectively is 0.25 mmol·L-1、0.2 mmol·L-1,0.75 mg·L-1. Chlorophyll content of Syringa microphylla is the hightest in SNP, Spd and EBR surueyed which respectively is 0.125 mmol·L-1、0.4mmol·L-1、 0.375 mg·L-1.2.Exogenous spraying SNP, Spd and EBR can delay MDA content and relative conductivity increasde. Relative conductivity of Syringa oblate and Syringa microphylla is the lowest in SNP, Spd and EBR surueyed which respectively is 0.25 mmol·L-1、0.4 mmol·L-1、 0.75 mg·L-1. MDA content of Syringa oblate and Syringa microphylla is the lowest in SNP, Spd and EBR surueyed which respectively is 0.25 mmol·L-1、0.4 mmol·L-1、0.375 mg·L-1.3.Exogenous spraying SNP, Spd and EBR has little influence on the soluble surger and soluble protein content of Syringa flooded.It also can decreased the activity of antioxidant enzymes SOD and POD. SOD activity of Syringa oblate is the lowest in SNP, Spd and EBR surueyed which respectively is 0.125 mmol·L-1、0.4 mmol·L-1、0.75 mg·L-1. SOD activity of Syringa microphylla is the lowest in SNP, Spd and EBR surueyed which respectively is 0.25 mmol·L-1、0.4 mmol·L-1、0.75 mg·L-1. POD activity of Syringa oblate is the lowest in SNP, Spd and EBR surueyed which respectively is 0.125 mmol·L-1、0.4 mmol·L-1、0.75 mg·L-1. POD activity of Syringa microphylla is the lowest in SNP, Spd and EBR surueyed which respectively is 0.25 mmol·L-1、0.4 mmol·L-1、0.37.5mg·L-1.To sum up,the best surueyed that can increase the ability of Syringa oblate to resistant the flooding stress are that SNP is between 0.125 mmol·L-1 and 0.25 mmol·L-1, Spd is between 0.2 mmol·L-1 and 0.4 mmol·L-1, EBR is around 0.75 mg·L-1. The best surueyed that can increase the ability of Syringa oblate to resistant the flooding stress are that SNP is between 0.125 mmol·L-1 and 0.25 mmol·L-1, Spd is around 0.4 mmol·L-1, EBR is between0.375 mmol·L-1 and 0.75 mg·L-1.