Study On Salt Tolerance And Cadmium Tolerance In Seedlings Of Tsoongiodendron Odorum And Paramichelia Baillonii

This study used annual seedings of Tsoongiodendron odorum and Paramichelia baillonii coming from Guangxi state Gaofeng forest farm as test material. They were dealed with salt and heavy metal through a method of pot experiment. The salt concentration were0.0%(CK),0.2%,0.4%,0.6%and0.8%and the Cd2+concentration were Omg/L (CK),10mg/L,50mg/L,100mg/L and150mg/L. The dynamic changes of growth and physiological and biochemical indicators of Tsoongiodendron odorum and Paramichelia baillonii were observed and determinated under different salt and Cd2+stress. Their ability and mechanism of resistance were analyzed by means of variance analysis, multiple comparison, correlation analysis, principal components analysis and fuzzy synthetic evaluation in order to providing a theoretical basis for protection and cultivation, introduction and domestication and greening of landscape. The results show that:1.The effects on growth and physiological indicators of Tsoongiodendron odorum and Paramichelia baillonii under salt stress were different. With the increase of salt concentration, seedling height and chlorophyll content of Tsoongiodendron odorum and Paramichelia baillonii decreased; growth of diameter, SOD activity and POD activity firstly increased and then decreased; cell membrane permeability, MDA content, soluble sugar and protein content increased; but the proline content of Tsoongiodendron odorum firstly decreased and then increased, the proline content of Paramichelia baillonii decreased. The result also showed that the range of changes varied due to different species and salt concentration.Correlation analysis showed that seedling height, cell membrane permeability, MDA content, protein content and chlorophyll content and salt stress concentration were significant or very significant correlation, so they could be used as evaluation indicators of salt resistance of Tsoongiodendron odorum and Paramichelia baillonii. Principal components analysis showed that the first principal components of Tsoongiodendron odorum and Paramichelia baillonii mainly incluced seedling height, growth of diameter, cell membrane permeability, MDA content, protein content and chlorophyll content; the second principal components mainly incluced SOD activity and sugar content and so on. The comprehensive evaluation of subordinate function values showed that the comprehensive values of subordinate of Tsoongiodendron odorum and Paramichelia baillonii were0.532and0.486, so the salt resistance of seedlings of Tsoongiodendron odorum was stronger than that of Paramichelia baillonii.2.The effects on growth and physiological indicators of Tsoongiodendron odorum and Paramichelia baillonii under Cd2+stress were also different. With the increase of Cd2+concentration, seedling height, growth of diameter, SOD activity and chlorophyll content of Tsoongiodendron odorum and Paramichelia baillonii firstly increased and then decreased; cell membrane permeability and MDA content increased; POD activity and proline content of Tsoongiodendron odorum first decreased slightly and then slowly increased, but theirs of Paramichelia baillonii firstly increased then decreased and at last increased. The result also pointed out that the range of changes varied due to different species and Cd2+concentration.Correlation analysis showed that cell membrane permeability and MDA content and Cd2+stress concentration were significant or very significant correlation, so they could be used as evaluation indicators of Cd+resistance of Tsoongiodendron odorum and Paramichelia baillonii. Principal components analysis showed that the first principal components of Tsoongiodendron odorum and Paramichelia baillonii mainly incluced growth of diameter, cell membrane permeability and MDA content; the second principal components mainly incluced SOD activity and proline content and so on. The comprehensive evaluation of subordinate function values showed that the comprehensive values of subordinate of Tsoongiodendron odorum and Paramichelia baillonii were0.483and0.495, so the cadmium resistance of seedlings of Tsoongiodendron odorum was weaker than that of Paramichelia baillonii.