A Comparison of Transpiration Characteristicsbetween Hippophae rhamnoides L.ssp sinensis Rousi and Hippophae ranmnoides in Huangfuchuan Watershed

Huangfuchuan watershed is located in the east part of the Ordos Plateau,NeiMongol.It is a key region for soil erosion control and ecoenvironment restoration in the middle reach of Yellow River.In 2002,the transpiration characteristics of Hippophae rhamnoides L.ssp sinensis Rousi and Hippophae ranmnoides were measured under natural conditions by using portable LI1600 stable stomatal.The results indicate that the transpiration rate of plants is deeply related to both of the conditions of plants themselves and the environmental factors.The change of diurnal and \{seasonal\} transpiration rate of Hippophae rhamnoides L.ssp sinensis Rousi is higher than that of Hippophae ranmnoides.It is showed that Hippophae rhamnoides L.ssp sinensis Rousi is more sensitive to environmental factors than Hippophae ranmnoides.