Effects Of Exogenous GA₃ And SA On The Salt Resistance Of Iris Germanica

To ascertain the induced role of exogenous GA3 and SA on the salt resistance of landscape plant and increase the plant species in saline soil. Iris germanica was used to study effects of different concentrations exogenous GA3 and SA on its growth index, the salt injured index and physiological parameters under 100 mmol/L NaCl stress with root injection and foliar spray. The main results were as follows:Effects of exogenous GA3 and SA on the growth of Iris germanica under salt stress were as follows:The growth of Iris germanica was restrained seriously by NaCl stress.exogenous GA3 and SA improved the growth status, the stem height, leaf length, total dry mass of plant increased substantially, the root shoot ratio and salt stress index reduced. G4(200mg/L),G3(100mg/L) were effective, but G4 turned up a bit spindling, stem and leaf were weak, the ornamental value decreased, so 100mg/L was better; S3 (200mg/L) was the best in the treatment of SA, S4 (300mg/L) turned up some side-effects to Iris germanica.Effects of exogenous GA3 and SA on photosynthesis and osmotic adjustment ability of Iris germanica under salt stress.The content of chlorophyll, relative water content, soluble sugar and soluble protein increased substantially after used GA3 and SA. the photosynthesis rate raise effectively, alleviate the salt stress injury of Iris germanica. Between two exogenous hormones, G3,G4 and S3 were more effective, the difference between G3 and G4 was not significant.Effects of exogenous GA3 and SA on cell membrane stability of Iris germanica under salt stress.After spraying optimum concentration of exogenous GA3 and SA, the activities of superoxide dismutase (SOD) and peroxidase (POD) improved, the Permeability of cell and MDA content decreased remarkably, enhance the salt tolerance of Iris germanica. GA3 was better than SA, G3,G4 were effective in the treatment of GA3, S3 was the best in the treatment of SA.The characteristic feature of exogenous GA3 and SA.The rigt concentration of exogenous GA3 and SA enhanced the salt tolerance of Iris germanica. But the effects of them were limited and existed some timeliness. By the analysis of the growth index and physiological parameters, reach a conclusion that between two plant hormones GA3 was better, and without a high concentration inhibition. But SA with a high concentration limited the growth of Iris Germanica. The result also showed the optimum treatment concentration of GA3 being 100 mg/L and SA being 200 mg/L.