Effects Of Exogenous GA₃ And SA On Physiological And Biochemical Characters Of Strawberry Under NaCl Stress

Strawberry was used as materials. Cultivated it under NaCl stress condition (40mmol·L^-1), then sprayed exogenous GA₃ and SA, the effects of exogenous hormones on physiological and biochemical characters of strawberry were studied. The main results were as follows:The growth of strawberry was restrained seriously by NaCl stress. The leaf area increased slowly, with the stress time prolonging, the index of salt damage of leaves increased, and the biomass decreased. Exogenous GA₃ and SA could effectively alleviate the restrain of NaCl stress, decrease the level of salt damage, and increase the leaf area and biomass.Growing under NaCl stress condition, the photosynthesis rate, transpiration rate and the stomatal conductance decreased. The intercellular CO₂ concentration rose, and with the time prolonging, it declined first and then rised. But the stomatal limitation vaule changed conversely, so the season of photosynthesis restrain under NaCl stress was stomatal limitation at first, then was non-stomatal limitation. At same time, the chlorophyll content reduced, especially the chlorophyll b. And the root vigor of strawberry declined. Exogenous GA₃ and SA could effectively raise the photosynthesis rate, transpiration rate and the stomatal conductance, increased utilization of CO₂ and increase strawberries chlorophyll content, and enhance the root vigor of strawberry.NaCl stress condition, the osmotic adjustment function of strawberry was stimulated, the content of proline, soluble sugar, and soluble protein increased. But with the treatment time prolonging, the content of osmotic adjustment materials reduced, and the salt damage was heavier, the water content of strawberry leaves decreased. Moreover, the NaCl stress caused substantial accumulation of Na⁺, Cl^- in strawberry intimate, formed ion toxicity, and declined the content of K⁺ and other useful ion. Sprayed exogenous GA₃ and SA, could further enhance the osmotic adjustment materials, at the same time could also maintain higher concentrations of these osmotic adjustment materials, maintain the water content of strawberry leaves. And exogenous GA₃ and SA could significantly reduce the content of Na⁺, Cl^-, and enhance K⁺ content, and reduced the upward transportation of Na⁺, Cl^-, and alleviate the salt stress injury of ground department.NaCl stress condition, severely affected the reactive oxygen metabolic system of strawberry, promote the membrane-lipid peroxidation. NaCl stress raised the O₂·^- generation rate, increased H₂O₂ and MDA content. NaCl stress could stimulate the activity of enzyme systems, such as SOD and POD, increase the content of non-enzyme systems,...