Effects Of Exogenous On Physiological And Biochemical Characters Of Strawberry Under Na₂SO₄ Stress

Strawberry is not only the important ecnomy plant but also the excellent cover plant. Strawberry is sensitive to salt. The aggravation of soil salt-pickled limits its proper growing range. For studying its salt tolerance and using exogenous GA3 and SA to decrease the level of salt damage is important to strawberry development. This experiment studied the effects of exogenous hormones on physiological and biochemical characters of strawberry, using strawberry as materials, cultivated it under Na₂SO₄ stress condition (0.4%), and spraying exogenous GA3 and SA. The results are summarized as below:1. The growth of strawberry was restrained under Na₂SO₄ 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 mitigate the level of salt damage, and increase the leaf area and biomass.2. Studies on physiological and biochemical characteristics of strawberry to Na₂SO₄ stress. Under Na₂SO₄ stress, the photosynthesis rate, transpiration rate and the stoma conductance decreased. The intercellular CO2 concentration rose, and with the time prolonging, it declined first and then rose. But the stoma limitation value changed conversely. At the same time, the chlorophyll content reduced and the root vigor of strawberry declined. Exogenous GA3 and SA could effectively raise the photosynthesis rate, transpiration rate and the stoma conductance, increase utilization of CO2 and strawberries chlorophyll content, and enhance the root vigor of strawberry.3. Under Na₂SO₄ stress, the content of praline, soluble sugar, and soluble protein increased. But with the treatment time prolonging, the content of osmotic adjustment materials reduced, and the Na₂SO₄ stress caused substantial accumulation of Na+ in strawberry intimate, formed ion toxicity, and declined the content of K+ and other useful ion. Sprayed exogenous GA3 and SA, could enhance the osmotic adjustment materials, and reduce the content of Na+, and enhance K+ content.4. Na₂SO₄ stress raised the O2·ˉgeneration rate, increased MDA content. Under Na₂SO₄ stress, with the treatment time prolonging, the activity of enzyme systems such as SOD and POD decreased, the content of non-enzyme systems declined. Exogenous GA3 and SA could significantly reduce the O2·ˉgeneration rate, enhance the activity of enzyme systems, increase the content of non-enzyme systems to a further level, then decrease the content of MDA. Thus, Exogenous GA3 and SA could protect the stability of membrane, soften the damage to strawberry plant and improve the ability of salt-resistance.