Studies On The Physiological Response Of Pyrus Betulaefolia Bge. Under Salt Stress And Screening Out Of Salt-tolerance Resources

With the Pyrus betulaefolia Bge. seedlings from five different origins including xinjiang Aral(XA), xinjiang Tiemenguan(XT), xinjiang Korla(XK), Gansu(GS), Shanxi(SX), two experiments were conducted to study salt injury index, the change of growth and physiological and biochemical indicators by both solution and soil culture. The main research results are as follows:1. Under salt stress, salt injury index of seedlings from GS and XT was the lowest, salt injury index of seedlings from XA and XK took the second place, seedlings from SX was the highest. With 0.36% soil salt concentration treatment, salt injury index of seedlings from XA, XK and SX reached 100% consistently, plants all died, and salt injury index of seedlings from GS and XT was 89.29%, seedlings from all origins were not resistant to 0.36% soil salt concentration.2. Under salt stress, plant height, leaf length and leaf width of seedlings from all origins were lower than those of control. Growth was inhibited, growth from different origins was different, plant height, leaf length and leaf width of seedlings from GS decreased unsignificantly and growth inhibited less than XA, XT, XK and SX.3. Under salt stress, the relative electrolyte leakage and MDA content in leaves of seedling from all regions increased and membrane permeability increased in seedlings from all origins. The relative electrolyte leakage of leaves in seedlings from SX increased significantly in the tenth day, but the relative electrolyte leakage of leaves in seedlings from XT and GS increased significantly in the thirtieth day with 0.3% Na Cl concentration treatment.4. Under salt stress, SOD and POD activities of leaves in leaves with seedlings from all origins increased, SOD and POD activities in leaves with seedlings from GS increased significantly. In contrast, CAT activity in leaves with seedlings from all origins decreased under salt stress, CAT activity in leaves with seedlings from SX decreased significantly.5. Under salt stress, proline, soluble sugar and soluble protein contents in leaves of all original seedlings increased under salt stress. Proline and soluble protein content in leaves of seedlings from GS and XT increased significantly, Proline and soluble protein content in leaves of seedlings from SX did not increase significantly6. Under salt stress, chlorophyll contents in leaves of all seedlings decreased significantly. Chlorophyll contents of seedlings from different origins were different, chlorophyll content in leaves of Pyrus betulaefolia from XT and GS had a lower decrement and chlorophyll content in leaves of seedlings from SX had a higher decrement.7. Uuder salt stress, seedling from GS and XT had the best salt tolerance, seedlings from XA and XK were in the second place and seedlings from SX had the poorest salt tolerance.