Salt Resistance Physiology Of Six Shrubs On Sandy Lands

In order to effectively use and meliorate saline and alkaline land in sand area,the dynamic changes of leaves water content,the relative conductivity,organic and inorganic substances osmotic adjustment,H₂O₂ content,SOD and CAT activity,MDA content are measured by using 6 kinds of one-year-old seedlings with salt controllable potted cultivation,such as Caragana korshinskii,Atraphaxis bracteata,Hedysarum mongolicum,Hedysarum scoparium,Buddleja alternifolia,Atriplex canescens.The salt resistance adaptation of 6 kinds of shrubs is explored by analyzing the physiological responses under varying intensity of salt stress.The results are as follows:(1) Under the salt stress condition,6 kinds of shrubs leaves water content decreased, where as MDA content and membrane permeability increased,impact of mild salt stress, moderate salt stress,heavy salt stress on 6 kinds of shrubs are increasing trend.The reaction to salt stress is different for 6 kinds of shrubs,and there are difference in many aspects,such as the relative water content in leaves,MDA content and the relative increase in electrical conductivity.Comprehensive changes of 3 indicators,the order of salt resistance of 6 kinds shrubs is given:Atriplex canescens＞Caragana korshinskii,Hedysarum mongolicum,Hedysarum scoparium＞Atraphaxis bracteata,Buddleja alternifoli.With 3 indicators change in the salt stress time,some Features are beneficial to the salt resistance of Caragana korshinsk,Hedysarum mongolicum,Hedysarum scoparium,Atriplex canescens,and some features are not beneficial to the salt resistance of Atraphaxis bracteata and Buddleja alternifolia.(2) There are difference in cumulative active oxygen,SOD and CAT activity,salt stress intensity and type of 6 kinds shrubs,cumulative active oxygen in a later stage of salt stress for Hedysarum mongolicumshow that the system of anti-oxidation protection can eliminate H₂O₂ effectively,and the ability of Anti-oxidative stress is high.At the primary stage of salt stress, Caragana korshinsk shows cumulative active oxygen,as salt stress time go on,cumulative active oxygen is eliminated,as well as Caragana korshinskii,Atriplex canescens does. Buddleja alternifolia shows cumulative active oxygen at different salt stress times,it is demonstrated that cumulative active oxygen can not be eliminated by oxidation protection system.The changes of SOD and CAT activity of Hedysarum mongolicum and Atriplex canescens show the same trendy of cumulative active oxygen.And the changes of CAT activity of Hedysarum scopariunm,Caragana korshinskii show the same trendy of cumulative active oxygen.Active oxygen can not be eliminated effectively by CAT activity of Buddleja alternifolia,Atraphaxis bracteata even if its increased,it may be related to SOD activity no rise with cumulative active oxygen simultaneously.(3) 6 kinds of shrubs can adapt themselves to salt stress environment by smotic adjustment.Proline,soluble protein and soluble sugar adjust osmotic adjustment Process of 6 kinds of shrubs.The changes of proline content show that Atriplex canescens is not sensitive to salt stress,under the heavy salt stress condition,the cumulative Proline and Suble protein for Atriplex canescens demonstrate that its salt resistance is high.For phaxis bracteata,soluble protein and soluble sugar do not appear in the earlier salt stress stage show that its osmotic adjustment is limited.(4) Both of Na⁺and Cl^-adjust osmotic adjustment Process of 6 kinds of shrubs.Its show that K⁺adjust osmotic adjustment Process of Caragana korshinskii,Hedysarum scoparium,Atriplex canescens and Buddleja alternifolia,and K⁺ not adjust osmotic adjustment Process of Atraphaxis bracteata.K⁺ is not a major material for osmotic adjustment Process of Hedysarum mongolicum.For Atraphaxis bracteata,K⁺ do not accumulate under the salt stress condition,it is not beneficial to its salt resistance and growth.Except forHedysarum mongolicum salt stress in the early stage,the ratio of Na⁺ and K⁺ content with salt stress experiment lower than with control experiment,especially under. the heavy salt stress condition for 4 kinds of shrubs,including Hedysarum mongolicum,Caragana korshinskii,Buddleja alternifolia,Atraphaxis bracteata.,The ratio of Na⁺and Cl^-content show decreased tendency with salt stress time.Compare salt stress experiment to control experiment,6 kinds of shrubs absorb K⁺ decrease relatively,while Na⁺ absorption increase under the salt stress condition with salt stress time.For Atriplex canescens,the ratio of Na⁺ and K⁺ content under the heavy salt stress condition is higher than under the mild and moderate salt stress condition,its salt resistance is high because of its more K⁺ absorption.For Hedysarum mongolicum,The ratio of Na⁺ and K⁺ content in the early salt stress period is high than control experiment,its salt resistance is high as well.