Effects Of SA And S3307 On Physiological And Biochemical Characteristics Of Lycium Ruthenicum Murri. Calli Under Salt Stress

Soil salination is one of the major factors that inhibit the growth of plant, which has become an important problem all over the world. Enhancing salt tolerance of plant has been thought to be a quite effective method to utilize and harness the saline soil. Lycium ruthenicum is a very rare halophyte, mostly distributed in the regions of northwest china and is characterized with salt tolerance, drought tolerance and cold tolerance. Lycium ruthenicum callus was selected as material in this study to analyse the physical changes under different concentrations of NaCl stress and effects of exogenous SA, S3307 and salt acclimation on its salt tolerance. The results showed that:1. Growth of Lycium ruthenicum callus was clearly inhibited under salt stress. Results of electrolyte leakage and MDA content showed that cell membrane was injured and degree of the injury increased along with the increasing salt concentration. POD, SOD, APX, GR activities were induced and fastly increased along with the increasing salt concentration in the beginning of treatment, which enhanced salt tolerance and constituted an enzyme protection mechanism that eliminated or alleviated the ROS injury under salt stress. Results of proline and soluble sugar content showed they were the major osmoticums and accumulation of them was also an important salt-tolerant mechanism of Lycium ruthenicum callus.2. Under salt stress, adding 10μM and 50μM concentration of S3307 to medium made growth situation of Lycium ruthenicum callus was superior to CK and high concentration 100μM)S3307 treatment group. Both 10μM and 50μM concentration S3307 treatments not only clearly decrease MDA and H2O2 content of callus, but also promote accumulation of soluble protein, proline and activities of POD, SOD and APX. The above demonstrated appropriate concentrations of S3307 treatment could enhance salt tolerance of Lycium ruthenicum callus.3. After Lycium ruthenicum callus was pretreated with different concentrations of SA 24 hours, growth situation of it under lower concentration (10μM) SA treatment group was better than mediate (50 mM), higher (5 mM) concentration of SA treatment groups and salt stress control group. Lower concentration SA pretreatment could decrease the MDA content of the callus under salt stress. Moreover, appropriate concentration SA (0.01 mM～0.5 mM) treatment could enhancing salt tolerance by increasing the antioxidative enzymes such as POD, SOD, GR and APX activities in a certain period. What is more, lower or mediate concentration SA treatment could defense salt stress by improving the accumulation of soluble sugar. The above demonstrated appropriate concentrations of SA pretreatment could enhance salt tolerance of Lycium ruthenicum callus.4. After salt acclimation in the medium with 50 mM NaCl 7 days, growth of Lycium ruthenicum callus under 200 mM NaCl salt stress was better than the control group. Salt acclimation not only decreased the MDA and H2O2 content, but also increased CAT, POD, SOD and APX activities of of Lycium ruthenicum callus under salt stress. Furthermore, salt acclimation increased soluble sugar and soluble protein content of Lycium ruthenicum callus under salr stress. In a word, salt acclimation could alleviate the injury of salt stress to Lycium ruthenicum callus and enhance its salt tolerance.