Physiological Biochemical Research And Evaluation Of Salt Tolerance Of Such As Celtis Sinensis

Celtis sinensis, Ulmus pumila L.and Ulmus pumila spp. are the annual seedling three species for the material, we simulated field Saline-alkali land with test tank and underground natural saline water. In order to further understand their salt tolerance mechanisms, the test studied their growth status, physiological and biochemical responses in different salt stress. As randomized complete block experiment was designed, CK?2‰?2.5‰?3.5‰?5‰five different gradients of soil salinity levels were prepared and we measured their growth status, cell membrane permeability, MDA, chlorophyll, the content of osmotic adjustment substance, protective enzyme activities, root activity, photosynthetic characteristics and chlorophyll fluorescence parameters. Multiple comparisons, correlation analysis, and other mathematical methods were employed to evaluate the salt resistance size of three tree species with Excel, SPSS and DPS. Thought analysis three tree species salt tolerance index for further research of ulmaceae plants salt-tolerance provided theoretical basis. Biomass, SOD, POD, CAT, soluble protein, soluble sugar, proline, malondialdehyde, membrane permeability, photosynthetic rate, stomatal conductance, intercellular CO2 concentration, transpiration rate, chlorophyll and chlorophyll fluorescence parameters of multiple indicators were as follows:The extent of inhibition and the plants symptoms of the three tree species seedlings under salt stress could reflect the differences of salt tolerance:Ulmus pumila spp.> Ulmus pumila L.> Celtis sinensis.In the whole experiment, with increasing salt content and prolonged stress time, the protective enzyme activities (SOD, POD, CAT) of Ulmus pumila Land Celtis sinensis. increased at first and then decreased. The protective enzyme activities (SOD, POD, CAT) of three tree species fell into the lowest in later period of 5%o salt stress, but, the protective enzyme activities (SOD, POD, CAT) of Ulmus pumila spp.arose increasing tendency in salt stress later period. Therefore, the protective enzyme activities (SOD, POD, CAT) play a very important role in salt resistance physiological activities.With increasing salt content and prolonged stress time, the soluble protein content of three tree species decreased obviously. In this experiment, the content of proline and salt stress strength had positive relations, and plants salt resistance had opposite relation.The experimental results show, the content of MDA and cell membrane permeability had a certain relationship:The greater cell membrane permeability, the higher the MDA content of the plants. The cell membrane permeability and MDA content of three tree species of trees were increased by salt stress. Celtis sinensis membrane system has been severely damaged in the late salt stress stage; MDA content and cell membrane permeability of Ulmus pumila spp. was lowest.Chlorophyll content of Celtis sinensis were always higher than that of Ulmus pumila spp.an Ulmus pumila L. in each stage of salt stress, and photo synthetic composition and the activity related enzymes to photochemical energy of Celtis sinensis were better than that under lower salt stress. Chlorophyll fluorescence changes of Ulmus pumila spp.was better than that of Celtis sinensis under 2.5%o salt stress; Relative growth, photosynthetic characteristics and fluorescence parameters of Ulmus pumila spp.had a more stable of change than others to adapt to salt stress conditions under high salt stress (>2.5%o). Therefore, Ulmus pumila spp.> Ulmus pumila L.> Celtis sinensis.Plant root activity can also reflect the plant salt resistance under salt stress, the experiment results show, root activity of Ulmus pumila spp.was the largest, then Ulmus pumila L., Celtis sinensis' was the smallest.It is difficult to accurately reflect the degree of salt tolerance of a single character or a determination results. Comprehensive evaluation of salt resistance need much more information. We comprehensive evaluated three tree spices salt tolerance by fuzzy membership function method. Finally, we can come to the conclusion:Ulmus pumila spp.> Ulmus pumila L.> Celtis sinensis.