Drought resistance of two Elaeagnus species under water stress.

Two years old seedlings of Elaeagnus mooceroftii and Elaeagnus oxycarpa were chosen and planted in field,then treated by different mount of irrigation in Moyu county of Xinjiang.The relative mean soil water contents of different irrigating treatment were 85%,70%,47% and 24%.by to measuring the water potential of E.mooceroftii and E.oxycarpa under different conditions and at different time,it was shown that their variation trends followed a "V" shape in whole day.The mean daily water potential of E.mooceroftii((-0.87±0.18) Mpa)was higher than that of E.oxycarpa.Comparing the net photosynthetic rate,transpiration rate and water use efficiency of two species,it is turned out the net photosynthetic rate((10.03±1.19) μmol·m-2·s-1),the transpiration rate((11.06±0.88) mmol·m-2·s-1)and water use efficiency((0.80±0.09) μmol·mmol-1) of E.mooceroftii were higher than that of E.oxycarpa.The δ13C value of E.mooceroftii(-26.06‰±0.08‰)was significantly higher than that of E.oxycarpa.The E.mooceroftii and E.oxycarpa grew well when the the soil water contents of different irrigating treatment were 85%,70% and 47%,while it was under significantly drought stress when under the soil water contents of different irrigating treatment were 24%,but the net photosynthetic rate and water use efficiency of E.mooceroftii were 3.26 μmol·m-2·s-1,0.06 μmol·mmol-1 higher than that of E.oxycarpa.The water potential of E.mooceroftii was 0.06 Mpa lower than that of E.oxycarpa.In a word,the drought resistance of E.mooceroftii was better than that of E.oxycarpa by Subordinate Function Value.