The Characteristics Of Drought Resistance Of Two Species Elaeagnus Angustifolia L.seedlings

Elaeagnus angustifolia L. is one kind of important economical tree in Xinjiang Uygur Autonomous Region. It has the strong compatibility to the drought. One-year-olds seedling of E. oxycarpa Schlecht. and E. mooceroftii Wall.ex Schlecht. were used in this experiment as materials .The control and three drought treatment were designed ,the soil relative water content is 70-75%,50-55%,35-40% and 15-20% respectively, water supply was controlled and treated about 30 days by the weight method in potted mulberry under the rainproof awning, to study systemically the changes of the growth, the osmosis adjustment, the photosynthesis characteristic and the protection enzyme activity. And discussed the research measures of drought-tolerant characters and evaluate drought-tolerant ability of Elaeagnus angustifolia L..Main results as follows:1) The growth of E.oxycarpa Schlecht. and E.mooceroftii Wall.ex Schlecht. was restrained when the soil relative water content is 35～40% and 15～20%. Both of them still kept on growing the biomass weight The plant height declined, the leafs expansion changed slightly, the thicking stem was restrained, dry matter and Root-Crown ratio increased, and the leaf relative water content declined and it also lose its original color. And the affect is most obvious under the soil relative water content of 15～20%, they can still grow, but the progress is extremely slowly. They resumed to fast growth after rewatering, moreover displayed the certain compensating growth effect.2) Along with the increasing degree of water stress, leaf chlorophyll content and chlorophyll a/b value, net photosynthetic rate, stomatal resistance,transpiration rate and water use efficiency of E. oxycarpa Schlecht. and E. mooceroftii Wall.ex Schlecht.were all decreased. Daily change of net photosynthetic rate was a singlepeak curve under the soil relative water content of 70-75% and 50-55%, but it becomes doublepeak curve under the soil relative water content of 35-40% and 15-20%. Moreover the decreased net photosynthetic rate was mainly caused by the stomatal factors under the soil relative water content of 70-75% and 50-55%, and non-factors 35-40% and 15-20%.3) Along with the increasing time and degree of water stress, the leaf's osmotic adjustment matter, such as soluble sugar content, Proline content and K+ content, increased, soluble protein decreased. the cell membrane systems of leaf of seedling of E.oxycarpa Schlecht. and E. mooceroftii Wall.ex Schlecht. were harmed and the cell membrane penetrability increased, relative electric conductivity and Malondiadehyde content increased. Different treatment suffered differently. Protective enzyme activities showed the variation tendency, Superoxide dismutase activities increased then decreased, Peroxidase, Catalase activities increased all the time of treatment.