Studies On Cold And Drought Resistance Of Pseudolarix Kaempferi

Pseudolarix kaempferi is a deciduous arbor, which is distributed in China. It has the straight trunk, beautiful body and rapid growth, so people love it very much. Pseudolarix kaempferi is known as one of the top five garden trees of the world. One-year old, eight-year old and thirty five-year old Pseudolarix kaempferi are used to survey the ability to resist cold and drought. The purpose of the study is to provide theory evidences of promotion application and production practice in garden. The conclusion as follows:1. The dynamic variation of leaf electrolyte osmotic ratio, MDA, SOD, soluble sugar, soluble protein and chlorophyll were determined using artificial controlled temperature at 5℃(comparison), 0℃, -5℃, -10℃, -15℃, -20℃. The results showed: The leaf electrolyte osmotic ratio firstly became increased and then became lower as the decreasing of the temperature. The lethal temperatures of One-year old, eight-year old and thirty five-year old Pseudolarix kaempferi were respectively -0.808℃, -6.378℃, -13.641℃. MDA, SOD activity, soluble sugar and soluble protein firstly became increased and then became lower as the decreasing of the temperature. Chlorophyll content firstly became lower as the decreasing of the temperature, then increased.2. The experiment set five stages(0d, 10d, 20d, 30d and 40d)to carry out a drought stress on Pseudolarix kaempferi. The dynamic changes of the correlation with physiological and biochemical indexes such as leaf electrolyte osmotic ratio, MDA, SOD, soluble sugar, soluble protein, chlorophyll, soil water and leaf relative water were determined. The results showed: The drought days and leaf electrolyte osmotic ratio reached to significantly positive correlation. MDA, SOD, soluble sugar and soluble protein firstly became increased and then became lower as the increasing of drought days, the soluble sugar content appeared a declined phenomenon at the time of ten days. The drought days and chlorophyll, leaf relative water content reached significantly negative correlation.3. From the results we can see: leaf electrolyte osmotic ratio, soluble sugar and chlorophyll were more sensitive to different treatments under temperature and water stress, the correlations were more significant so they can be served as the major indexes of cold resistance and drought resistance identification.4. Pseudolarix kaempferi, unique to China, can be used as the Landscape-forests, leaf-colored tree and garden ornamental tree. In order to protect and exploit its germplasm, we should strengthen its basic research, germplasm collection and preservation, the configuration of garden plants, and so on.