Comparative Study On The Saline-alkali Tolerance Physiological And Ecological Character Of Leymus Chinensis And Chloris Virgata In Songnen Plain

In order to further screen salt tolerance gene,breed high saline-alkali tolerance grass and improve Grassland saline-alkalized of Songnen Plain,the Dynamic Change and response of physical,ecological indexes of Leymus chinensis and Chloris Virgata under salt and alkaline stress was studied by using method of combined major grass dominant plants which were Leymus chinensis and Chloris Virgata respectively existed in the wild grass of different salinity levels ( PH was 7.56,8.18,8.3,9.2,9.81 respectively and the total salt amount was 0.05%,0.12%,0.15%,0.24%,0.32% respectively.) with indoor simulated habitat (Different gradient salt mixture and PH was 7,7.7,8.4,9.1,9.8 respectively ).The results were as follows:1,The Physiological Responses of Leymus chinensis and Chloris Virgata to Saline-alkali stressWith the increase of Saline-alkali stress intensity, plasma membrane permeability,the free proline content and the free sugars content was increased in the leaves of Leymus chinensis and Chloris Virgata, but leaf chlorophyll content,plant moisture content and root activity was decreased. Leaf plasma membrane permeability and the MDA content in Grass had negatively correlation with saline-alkali tolerant. Leaf chlorophyll content,the free proline content, the free sugars content,plant moisture content and root activity had positively correlation with saline-alkali tolerant.We selected 7 Indexes,which were leaf plasma membrane permeability,leaf chlorophyll content,the free proline content,plant moisture content, the free sugars content,the MDA content and root activity respectively and by applying subordinate functions,we also studied comprehensive appraisal on salt-alkali tolerance of Leymus chinensis and Chloris Virgata.2,The Ecological Response of Leymus chinensis and Chloris Virgata to Saline-alkali stressHigh saline-alkali stress could inhibit growth of Leymus chinensis and Chloris Virgata and the height of grass group,frequency,density,coverage and above-ground biomass had apparently decreased tendency,but lower saline-alkali stress (pH8.18, the total salt amount is 0.12% ) could promote growth of Leymus chinensis and the height of Leymus chinensis, frequency,density etc.were slightly increased.In the same growth over period of Leymus chinensis and Chloris Virgata,difference of altitude,frequency,density,coverage and above-ground biomass were gradually become smaller with the increased Saline-alkali stress and this shows that Chloris Virgata was more salinity than Leymus chinensis.