Study On Physiological And Biochemical Characteristics And Nitrogen Regulation Of Potato Under NaCl Stress

Three potato cultivars ,Zihuabai,Atlantic and Kexin12,were used to do an experiment which researched the responses of potato plantlets and microtuber in vitro to NaCl stress and the effects of nitrogen on physiological and biochemical characteristics of potato under NaCl stress.in vitro.The results showed:1 The growth of potato was inhibited severely under NaCl stress. With the increase of NaCl concentrations,plant height of three potato cultivars decreased significantly; The growth of three potato cultivars stem and leaves and root declined in higher NaCl concentrations.However , stem diameter increased with the increase of NaCl concentrationsand .2 Under NaCl stress,chlorophyll content and root activity in potato decreased significantly with the increase of NaCl concentrations;The praline content and relative electric conductivity increased significantly with the increase of NaCl concentrations;The activity of SOD and POD in three potato cultivars changed in affinity,containing the tendency dramatically increased in special NaCl concentrations,but the range of changes among cultivars was different. When NaCl concentrations reached 0.3% and 0.45%,the two enzyme activity of Kexin 12 increased rapidly and was significantly higher under the concentration of 0.45% than that of the contrast; The two enzyme activity of Zihuabai changed stablly under NaCl stress, and was no significant difference; two enzyme activity of Atlantic was lower than the contrast in different concentrations;The protein and soluble sugar content in potato decreased under NaCl stress ,and the content of MDA had no significant difference;The relative water content in potato increased With the increase of NaCl concentrations,and demonstrated that the injury of salty to potato was through ion injury in main but not physiological drought.3 The formation of potato microtuber in vitro was delayed and the production decreased with the increase of NaCl concentrations;The activity of POD in potato microtuber in vitro increased generally,and the activity of SOD performed increasing at first,then decreasing with the increase of NaCl concentrations;The concent of starch,dry matter and protein all decreased.4 The tendency of chlorophyll and protein content performed increasing at first,then decreasing with the increase of nitrogen level,and reached the top in N2 level;Nitrogen could increased significantly the activity of SOD and POD in potato,and also could increased significantly the activity of root,furthurmore,it had higher activity under the sutible nitrogen content;But nitrogen could not release the growth of potato under salty stress effectively.