Response Of Seedlings Of Ailanthus Altissima Etc Four Species To Salt Stress Treatments

In this experiment, morphologies , physiological and biochemical performances under salt stress of honeysuckle (Lonicera japonica Thunb),Jinye Caryopteris (Caryopteris clandonensis'Worcester Gold '),Salix (Salix gordejevii Chang et SKV) and Ailanthus altissima (Ailanthus altissima (Mill ) Swinge) were observed and measured by the method of simulation of saline salt pond. And salt-tolerance mechanism and salt-tolerance of the tested species were preliminarily studied, the research results are as follows:It showed that the tested species in mortality and symptoms of salt injury were different in salt resistance. The order of salt resistance of the tree is Salix> golden >caryopteris>honeysuckle.With the increasing of salt concentration ,MDA contents increased gradually。MDA contents among those four species in each test were reached a significant level, indicating that salt stress severely damaged biofilm and caused lipid peroxidation. Under heavier salt stress,the contents of MDA and salt resistance apoeared significantly negtive correlationship.Under salt stress treatments proline contents in leaves of 4 species were significantly increasing, The relative amount of proline increments and species salt resistance apoeared significantly negtive correlationship.As the levels of salt treatments became higher ,the cell membrane and SOD activity were increased and the soluble protein contents,root activity and net photosynthetic rate were decreased. But for those species with the increasing of salt stress time, MDA,SOD,Pro,soluble sugar and soluble protein did not present a single variation trend.The relative increased amount of them were not related to salt resistance of those species .Under salt stress condition, Na+ accumulated in the roots more than that in leaves of Ailanthus altissima and Salix .Na~+ was retained in the roots so that the poison of overground part was reduced. Gold leaf Caryopteris and honeysuckle ,Ailanthus altissima and Salix is at high salt stress condition,the root selectively transported K~+ to stems and leaves while it limited to transport Na~+ so as to reduce their damage level.Photosynthesis of four species is very sensitive to salt stress. Stomatal closed in light salt stress and net photosynthetic rates were reduced. Ci analysis showed that the stomatal closure was not the only limiting factor to lead to the decreasing of net photosynthetic rates. Chlorophyll contents of four species was decreased by the salt stress. For most species it occurred in the heavy salt stress level. The range of chlorophyll content reduced was negatively related of tree species.Comprehensive analysis showed that all of those after the salt stress produced injure symptoms and physiological and biochemical respones undersalt stress condition .It is hard to find any single index ,which can evaluate the salt resistant ability of thoes species.It is belived that the traits of salt resistance is controlled by multiple genes and needed more research.