干旱区生态环境知识资源中心

For a long tithe dioecious plants have played an important role in examination of the reproduction cost and determination of the sexual dimorphism evolution in life history. Hippophae rhamnoides sinensis, a dioecious, outcrossing plant, occurs mainly in the arid regions of northwest China, contributes to maintain the local ecosystems in these regions. In this study, delta C-13 and the stomatal density of herbarium sheet were measured in Hippophate rhamnoides sinensis. It was found that the plants showed gender-difference in carbon isotope compositions: the males maintained higher delta C-13 values and thus higher water use efficiency as well as slightly higher stomatal density than the females, moreover, the between-sex difference is stable in different contexts through carbon isotope discrimination. Although we found that the stomatal density had being reduced and is sensitive to atmospheric CO2 level, delta C-13 value and thus water-use efficiency did not significantly change from 1978 to 2001. Consequently, gender-specific delta C-13 could play a decisive role in explaining gender differences in the developmental growth. (c) 2009 SAAB. Published by Elsevier B.V All rights reserved.