Effects Of Exogenous GA₃ And 6-BA On Physiological And Biochemical Characters Of Different Strawberry Varieties' Under NaCl Stress

In this paper, salt-tolerant variety of Xiang Fei (X) and salt-sensitive variety of Elsanta (A) were used as the tested materials.The strawberries were stressed by 34.5mmol/L NaCl and were eased by spraying 50μmol/L 6-BA and 72.25μmol/L GA3. The effects on the growth of different strawberry varieties and physiological, biochemical characteristics of exogenous hormones on NaCl stress were studied. The main results indicated as follows:1. Under NaCl stress, the growth of two strawberry varieties was vestricted. The leaf area increased slowly, and the degree of the leaves injured increased, while the plant biomass decreased with the time going, after easing by spraying exogenous GA3 and 6-BA, the leaf area of two strawberry varieties increased, and leaves injury was slso mild, the plant biomass increased. After spraying exogenous GA3 and 6-BA, the increase rate of leaf area and biomass in the salt-tolerant varieties of Xiangfei was larger than salt-sensitive variety of Elsanta. Within the same varieties, the increase rate of leaf area and biomass in 72.25μmol/L GA3 treanment was higher than that in 50μmol/L 6-BA treatment.2. Under NaCl stress, the metabolism system of reactive oxygen species in the two varieties were seriously affected, and the effects of lipid peroxidation increased. malondialdehyde (MDA) content increased and SOD (superoxide dismutase), POD (Peroxidase) activities increased, the AsA (ascorbic acid) in non-enzyme system increased, but with the time going, SOD, POD activity decreased, AsA content decreased also. Exogenous GA3 and 6-BA could further enhance the SOD, POD and AsA content of active oxygen scavenger, reduced MDA content, maintained cell membrane stability. After spraying exogenous GA3 and 6-BA, the increasing rate of SOD, POD activity and AsA in Xiangfei was lower than that in Elsanta. Within the same varieties, the increase rate of SOD, POD activity and AsA content in 72.25μmol/L GA3 treatment was higher than that in 50μmol/L 6-BA treatment.3. Under NaCl stress, the contents of proline, soluble sugar and soluble protein in 2 strawberry varieties increased significantly in the early treatment, but with the time going, the osmotic adjustment materials and the leaf water content of 2 strawberry varieties decreased. After spraying GA3 and 6-BA, Exogenous GA3 and 6-BA treatment, the increase rate of proline, soluble sugar and soluble protein content in salt-tolerant variety of Xiangfei were lower than that in salt-sensitive varietyh of Elsanta. Within the same varieties, the increase rate of proline, soluble sugar and soluble protein content in 72.25μmol/L GA3 treatment was higher than that in 50μmol/L 6-BA treatment.4. Under NaCl stress, the chlorophyll content of 2 strawberry varieties decreased, root activity increased in the beginning and then decreased. Exogenous GA3 and 6-BA could slow down the reduction rate of chlorophyll content effectively and significantly improve the strawberry root activity.5. The effect of 72.25 mg/L GA3 treatment was better than 50μmol/L of 6-BA treatment.