Study On Salt Tolerance And Salt Reduction Effect Of Plants In Cold And Arid Environment In Xining Basin

blished test site in Changlinggou,Xining Basin has been planted with species adaptable to climatic and geological conditions in the Xining Basin and surrounding areas.After selection,three shrubs and three herbs have been determined for further research.And these species are Caragana korshinskii Kom.,Zygophyllum xanthoxylon?Bunge?Maxim.,Lycium barbarum L.Medicago sativa L.,Elymus nutans Griseb.,Agropyron trachycaulzum?Linn.?Gaertn.To investigate the influence of salt stress on the germination and growth response of these species,Na₂SO₄ solution with concentration of 0 mmol/L,50mmol/L,100mmol/L,150mmol/L and 200mmol/L been applied.At 30 days of salt stress,germination,growth,physiological and mechanical indices have been determined as well as an assessment on the salt-tolerance ability to the species by membership function.And values of K⁺/Na⁺,Ca²⁺/Na⁺,Mg²⁺/Na⁺ in above-ground parts and underground parts have been obtained to reveal salt-tolerance ability of these species.And mono-plantation and inter-plantation have been exerted on the species in the self-established test site and content of salt ions(K⁺,Ca²⁺,Na⁺,Mg²⁺,SO₄^2-,Cl^-,HCO₃^-,and CO₃^2-)in vertical and horizontal directions in roots range have been determined to further probe the variation of salt contents to evaluate desalinization ability of the species and the following conclusions have been obtained:?1?Salt solution in any concentration has a depressive effect on germination of the species.And depressive effect increases with salt concentration increasing.And with salt concentration increasing,germination rate,germination exponent,germination potential and active exponent decrease.?2?Plant height,basal root diameter and dry weight drops as salt concentration increasing,and a significant difference exist among the species stressed in different solutions,which reflects herbs have been depressed essentially and depressive effects is linearly correlated with slat solution concentration.?3?Proline content,relative electrolytic conduct,MDA content,superoxide dismutase content,superoxide dismutase content and catalase content increase with salt solution concentration increasing and chlorophyll content decrease with salt solution concentration decreasing.?4?The average value of K⁺/Na⁺ of three shrub plants from large to small are Caragana korshinskii Kom.,Lycium barbarum L.and Zygophylluw xanthoxylon?Bunge?Maxim.,namely the three kinds of shrub plants in salt tolerance from large to small are Caragana korshinskii Kom.,Lycium barbaum L.and Zygophyllum xanthoxylon?Bunge?Maxim..The average value of K⁺/Na⁺of three herb plants from large to small are Medicago sativa L.,Agropyron trachycaulzum and Elymlmus nutans Griseb.,namely the three species of herb plants salt tolerance from large to small are Medicago sativa L.,Agropyron trachycaulum and Elymus nutans Griseb.?5?Single planting of Zygophyllum xanthoxylon?Bunge?Maxim.,Caragana korshinskii Kom.,Lycium barbarum L.,Medicago sativa L.,Elymus nutans Griseb.and Agropyron trachycaulum have relatively significant effects on reducing SO₄^2-?Ca²⁺ and Na⁺ in slope soil.The assemblage ? of herbs and shrubs,assemblage ? and assemblage ? have significant effects on reducing SO₄^2-?ca2+?Mg²⁺ and K⁺ in slope soil.?6?The total salt contents of the slope soil are reduced after the single planting of Zygophyllum xanthoxylon?Bunge?Maxim.,Caragana korshinskii Kom.,Lycium barbarum L.,Medicago sativa L.,Elymus nutans Griseb.and Agropyron trachycaulum,the decrease in total salt contents of slope soil before and after single planting are more obvious is Lycium barbarum L.,Elymus nutans Griseb.and Medicago sativa L.,followed by Caragana korshinskii Kom.and Agropyron trachycaulum,Zygophyllum xanthoxylon?Bunge?Maxim.is not relatively obvious.?7?Under the assemblage planting conditions of the three herbs and shrubs,the total salt contents of the slope soil show significant features,in which the total salt reduction of assemblage I is generally lower than that of assemblage II and assemblage III,which explain that the effect of salt reduction of herbs and shrubs assemblage ? and ? significantly relative to the assemblage of herbs and shrubs assemblage ?.