The Characteristics Of Drought Resistance Of Seedlings Of Five Tree Species

Maple(Acer mono Maxim Carr),Persimmon(Diospyros lotus Linn),Panicled Goldralntree(Koelreuteria paniculata Laxm),Chinaberry(Melia azedarach) and Black Locust (Robinia pseudoaacia Linn) are the main tree species in afforestation in the arid and hemi-arid areas of Shandong。one-year-old seedings of those five tree species have been used as materials to study the characteristics of drought resistance for each tree Species。The tested traits include water potential of leaves,the relative water deficient,leaf water holding capacity,stomatal conductance,transpiration conductance,activities of SOD ,CAT,POD,NR,the content of Pro and soluble protein and MDA,the content of chlorophyll, the permeability of protoplasm membrane ,the ratio of root to stem ,the relative growth rate and the growth fractals of root。The characteristics of drought resistance for each tree species are studied by testing those traits and indexes 。The result shows that each tree species has their own drought resistance characteristics and the drought resistances are correlated and indicated by specific traits,variance analysis ,multiple comparison,correlation analysis and main components analysis were conducted to reveal the inherent mechanisms of drought resistance and the relationship of tested index,and to determine the major index highly related to drought resistance evolution and selection。The result are as followings:SOD,the content of soluble protein and transpiration conductance ,the relative water deficient and the ratio of root to stem are strongly related to the ability of drought resistance of Black Locust (Robinia pseudoaacia Linn),and they are the key characteristics responding to drought stress。SOD,CAT,leaf water holding capacity ,transpiration conductance and the content of soluble protein are highly related to the ability of drought resistance of Chinaberry(Melia azedarach) and they are the key characteristics responding to drought stress。The content of Pro ,NR and the ratio of root to stem are highly related to the ability of drought resistance of Maple(Acer mono Maxim Carr),and they are the key characteristics responding to drought stress。SOD,CAT ,the content of MDA and the ratio of root to stem are strongly related to the ability of drought resistance of Panicled Goldralntree(Koelreuteria paniculata Laxm) and they are the key characteristics responding to drought stress。The content of MDA and soluble protein,Pro,the activities of NR,the varieties of chlorophyll。and the ratio of root to stem are strongly related to the ability of drought resistance of Persimmon(Diospyros lotus Linn) and they are the key characteristics responding to drought stress。From above ,such as traits SOD ,soluble protein and the ratio of root to stem are all closely related to drought resistance of those five tree species。The high activities of SOD ,the high content of dissolveprotein and the big ratio of root to stem all means the high about drought resistance ability。By comparison of those index,the different characteristics about drought resistance of each tree species can be summarized as followings:the water potential of leaves,stomatal conductance and transpiration conductance of Maple(Acer mono Maxim Carr) and Chinaberry(Melia azedarach) were higher than other tree species。On the other hand,the activities of SOD,CAT,POD and NR of Melia azedarach are very high and the content of osmotic matter are greater than other tree species。 Water potential descended and the damage by the destructive oxidation was lessened 。Especially,the roots of Chinaberry(Melia azedarach) are very strong and have the outstanding ability of absorbing water from soil 。On the contrary ,the water potential of leaves and stomatal conductance,Transpiration conductance of Black Locust (Robinia pseudoaacia Linn)and Panicled Goldralntree(Koelreuteria paniculata Laxm)were lower than other tree species。By closing stoma earlier and adjusting the...