Effects Of Potassium Ion On Physiological Property Of Mains Zumi Seedling Under Salt Stress

Soil salinization caused by natural or human activity is a major environmental risk.Soil salinization,damageing about831million hm2in global. It has seriously restricted thedevelopment of modern agriculture in our country. Most of the plants will be damaged whenthe soil salt content is0.3%and can’t grow when more than0.5%. So soil salinization causedgreat degree of threat to plant growth and agricultural production. Nowdays, there are manydifferent kinds of salt-tolerant plants and more than1560kinds of halophytes around theworld, many of them have important economic value. Today， population growing,cultivated land decreasing, freshwater resources shorting, cultivate salt-tolerant and economicplant and strengthen the researches on the mechanism of the salt tolerance of plants isbecoming more and more important to the sustainable development of agriculture.The material of this study is Malus zumi seedings, determinating photosynthesischaracteristic index, antioxidant enzyme activity, malondialdehyde content, free proline,soluble sugar and soluble protein and other physiological indicators under salt stress or saltstress followed by KCl processing. The two results are systematically comparative analyed toexplore the influence of K+on physiological characteristics of Malus zumi under salt stressand Provide a theoretical basis for its application in different kinds of salt soils. The maincontents and results of the research are as follows:1.More than50mmol·L-1concentration of KCl deal with Malus zumi seedings under saltstress, the Pn, Gs, Ci, Tr as well as Pigment content and fluorescence characteristics relatedindicators are higher than that of single NaCl processing. Meanwhile, by increasing thephotosynthetic pigment content as well as light energy conversion efficiency and electrontransfer rate in PSⅡ reaction center, seedling photosynthesis, K+facaliate photosynthesis ofMalus zumi seedings.2. Less than50mmol·L-1concentration of KCl deal with Malus zumi seedings under saltstress, the activity of SOD,POD,CAT and APX are higher than that of single NaCl processing.By contrast, the concentration of MDA is lower. It Shows that K+can enhance the activity ofantioxidant enzymes as well as eliminate Reactive oxygen so as to reduce MDA content,which reducing damage of salt stress to the plasma membrane of Malus zumi. 3. More than50mmol·L-1concentration of KCl deal with Malus zumi seedings under saltstress, The proline and soluble sugar and soluble protein content are higher than that of singleNaCl processing. It indicates that K+has a role in promoting permeability of Zumi seedings.however, the interaction mechanism of K+and Na+remains to be further research.Above all: K+can improve different kinds of physiological indexes of Malus zumiseedings under salt stress when the concentration is between50mmol·L-1and150mmol·L-1.