Comparison Of Salt Resistance Of Seed And Cold Resistance Of Branch In Six Type Of Lycium Ruthenicum Murr

Objective: The salt and cold tolerance of six type of Lycium ruthenicum Murr were compared to provide a theoretical basis for promoting the best type in Northern Xinjiang Province.Method: The experiment material included three ecotypes of L.ruthenicum（Xining Wild,Korla Wild,Wuwei Wild）and the corresponding promising selection（Xining promising selection,Korla promising selection,Wuwei promising selection）.The seeds were treated with NaCl concentrations of 50,100,150,200,250,and 300mmol·L^-1.A standard of 50 percent germination rates was set for production requirements.Seeds were considered to be under significant restrain when the germination rates were less than 50 percent.Seed germination rate,relative salt injury rate,salt tolerance concentration,and seedling growth were measured under different NaCl concentrations.And the branches were treated with low temperature of 4℃,-25℃,-30℃,-35℃,-40℃.The relative conductivity,malondialdehyde,superoxide dismutase,peroxidase and catalase activity,soluble protein,soluble sugar,proline content were measured after different low temperature.Correlation analysis,subordinate function and principle component analysis were used to evaluate the cold tolerance among six type of Lycium ruthenicum Mur.Result:（1）Germination rate,seedling growth decreased as NaCl concentrations increased from 50 and 300 mmol·L^-1.Regression analysis was conducted to determine the relationship between NaCl concentration and germination rate.The regression analysis indicated that the suitable NaCl concentration was greater for the promising selection type seeds than for wild seeds.The suitable NaCl concentration was150-300 mmol·L^-1 for the promising selection type seeds and 100-150 mmol·L^-1 for the wild seeds.The promising selection Wuwei type and the promising selection Korla had relatively high salt tolerance,whereas other type had relatively low salt tolerance.（2）The relative conductivity was increased with the decrease of temperature.The content of malondialdehyde was increased first and then decreased and after increased.The activity of superoxide dismutase was decreased first and then increased,and reached the maximum at-35 ℃,then decreased at-40 ℃.Peroxidase activity of Wuwei promising selection was increased first and then decreased and after increased.The change trend of peroxidase activity of other type was “low-high-low-high”.Catalase activity of Wuwei promising selection was decreased at-25^-30 ℃.The change trend of catalase activity of other type was increased before-35℃,besides Korla promising selection,other type under low temperature reached the maximum at-35 ℃.Soluble protein content of Korla Wild and Xining promising selection was“low-high-low-high”.The change trend of soluble protein content of other type was decreased first and then increased.Soluble sugar content of Wuwei Wild and Wuwei promising selection was “low-high-low-high”.The change trend of soluble sugar content of other type was decreased first and then increased and after decreased.The change trend of proline content was “high-low-high-low”.（3）Correlation analysis showed that the content of malondialdehyde,soluble sugar,superoxide dismutase,catalase activity can be used as key indexes to determine the cold resistance of six type of Lycium ruthenicum Murr.Adopted the principal component analysis,and the combination of principal component analysis and subordination function method,to evaluate the cold tolerance of six type of Lycium ruthenicum Murr.The results indicated that among the six type,the promising selection Xining type and the wild Korla had relatively high cold tolerance,whereas wild Xining type and the promising selection Wuwei had relatively low cold tolerance.Conclusion: The results showed that among the six type,the promising selection Wuwei type and the promising selection Korla had relatively high salt tolerance,whereas wild Xining type and wild Wuwei had relatively low salt tolerance.Basing subordinate function and principle component analysis,the order of cold resistance of six type of Lycium ruthenicum Murr.was Xining promising selection,Korla Wild,Korla promising selection,Wuwei Wild,Xining Wild,Wuwei promising selection.