Studies On Mechanism Of Calcium To Strawberry's Drought Resistance

Strawberry (Fragaria Ananassa Duchesne), which is one of perennial herbagefruit tree of living in the temperate zone, is popular in the international fruit market,called 'the queen fruit'. Some reasons have effect on strawberry's quality and output,which its root distribute so fleet, its leaf square is so large and its transpiration is soblooming, then result in lacking of enough water in the condition of drought. However,in the south of China, there is a difficult problem that the strawberry informally live inthe summer season because of high temperature with drought. If we are able toimprove the drought-resistance according to chemical materials, increase its output.Calcium is not only one of the necessary nutrition element, but also is secondmessenger in plants which modulation the activeness of enzymes, expression of genesand function of cells with CaM. The result is that calcium-CaM messenger take partin plants' resistance reaction. Calcium fertilizers can keep the balance of AOmetabolism and keep the steady structure of cell velum.In order to find out the best concentration of outside calcium, this experiment ison the basis of methods of nature drought stress, used the Zhangji and Fengxiangexperimental material, studied the effect of physiological and biochemical of differentconcentration of Ca²⁺ on strawberry, made the comparison of the content of calciumand CaM of different test strawberry in the end period of drought stress. We got thefollowing results.1. Under the drought stress, compared with the 0mmol/L Ca²⁺, the leaves' watercontent of strawberry can be stayed a⁺ high level in the unit of 5—20mmol/L Ca²⁺test, but the 30mmol/L Ca²⁺ decrease rapidly.2. In the process of the drought stress, strawberry's relative conductance rate andMDA content are constantly increase, but it reduced under 5—20mmol/L Ca²⁺ test,which release the membrane lipid peroxidation and protect the cell velum.3. Pro and soluble sugar are most important osmotic adjustment material. In theprocess of drought stress, they are continuously cumulate. Under 5—20mmol/L Ca²⁺test, the range of their accumulation is higher than the driver, which enhance the strawberry's osmotic adjustment ability.4. Under 5—20mmol/L Ca²⁺ test, protective enzyme of strawberry SOD,POD,PPO appear on some trend that from rise to drop, when the 10d activity higher thandriver, keep it. At the same time, stay non- protective enzyme AsA drop and decreasedamage of strawberry from the AO.5. Under drought stress, the content of soluble protein varies with the extent ofdrought stress, which from rise to drop and rise again. Under 5—20mmol/L Ca²⁺ test,to some extent its content increase. Drought-induced protein may have positive effectto improve strawberry's drought resistance.6. Under drought stress, the chlorophyl content of strawberry present drop trend,but 5—20mmol/L Ca²⁺ test stay it. So it has significance to keep strawberry'sphotosynthesis ability and normal physiological function.7. Under drought stress, 5mmol/L and 10mmol/L Ca²⁺ test can increase thecontent of endogeny calcium, then improve the drought resistance of strawberry. And5mmol/L Ca²⁺ test can increase the content of endogeny CaM, because CaM adjustinner enzyme activity, improve the drought resistance of strawberry.In all, 5—20mmol/L Ca²⁺ test can improve drought-resistance of strawberry insome extent, the 10 mmol/L Ca²⁺ test is the best, the 30 mmol/L Ca²⁺ test is not reachideal result, which give the scientific basis for calcium application in producing. So,CaCl₂ fertilizer is an economic and convenience method to improve strawberry'sadapt ability under drought stress.