Effect Of Exogenous NO On The Antioxidant System Of Taxus Seedlings Under Simulated Acid Rain Stress

Taking the 2-year-old seedlings of Taxus cuspidata,Taxus mairei,Taxus wallichiana,Taxus chinensis and Taxus yunnanensis as experimental material,this paper studied the influence of exogenous NO donor SNP solution on the antioxidant system of Taxus Linn seedlings under the simulated acid rain stress(pH=3.0).The results of the study show as fllows:1.Under the simulated acid rain(pH=3.0)stress the leaf malonadehyde(MDA)contents and superoxide radical(O2.-)production rate in leaves of Taxus Linn increased significantly(P < 0.05,similarly hereinafter);the contents of glutathione(GSH),ascorbic acid(ASA)and carotenoids decreased obviously;the activities of peroxidase(POD),superoxide radical(SOD),catalase(CAT),polyphenol oxidase(PPO),ascorbate peroxidase(APX)and glutathione(GR)decreased markly.2.In conclusion,the exogenous NO can effectively improve the activity of antioxidant system of Taxus Linn seedling under the simulated acid rain stress,the most effective treatment of the Taxus cuspidata is the concentration of 0.1 mmol·L-1.It can effectively improve the activity of antioxidant system ofTaxus chinensis seedling,when the concentration of SNP solution is 0.1 mmol·L-1.SNP with concentration of 0.5mmol·L-1 could significantly improve the activity of antioxidant system of Taxus mairei,Taxus wallichiana and Taxus yunnanensis seedlings.3.In the leaves of Taxus cuspidate seedlings,the antioxidant enzyme system and antioxidants play an equally important role in the antioxidant system.The antioxidant enzyme system plays a more important role in the antioxidant system than the antioxidants in the leaves of the Taxus mairei,Taxus wallichiana and Taxus yunnanensis seedlings.On the contrary,the antioxidants plays a more important role in the antioxidant system in the leaves of the Taxus chinensis seedlings.4.The ability of dfferent kinds of Taxus chinensis on resisting the effect of simulated acid rain is varies.Among it,the Taxus cuspidate did the best.Acid rain resistance intensity of Taxus chinensis、Taxus wallichiana、Taxus mairei and Taxus yunnanensis decreasing in turn.5.The effects of SNP on antioxidant properties of different species of Taxus chinensis are different,and this difference related to different species.Specific performance present as follow:The SNP treatment has the strongest effect on the Taxus yunnanensis,which under the simulated acid rain.While,this effect decreases as the order of Taxus chinensis、Taxus wallichiana、Taxus mairei and Taxus yunnanensis.