塔克拉玛干绿洲外围胡杨林的水分特征研究.pdfVIP

应用与环境生物学报 2007，13(6)：763～766 Chin JApplEnvironBiol=ISSN1006-687X 塔克拉玛干绿洲外围胡杨林的水分特征研究术 李向义 林丽莎 张希明 曾凡江 (中国科学院新疆生态与地理研究所 乌鲁木齐 83001 1) 摘 要 塔克拉玛干沙漠南缘地区年均降水量不足50 mm，胡杨在这一地区绿洲外围自然植被中占有重要地位．对塔 克拉玛干沙漠绿洲外围胡杨林水分特征的研究表明，在生境地下水含量较稳定的条件下，胡杨林受到的水分胁迫程度 不大，干旱胁迫未对胡杨林的持续存在构成主要威胁．胡杨的水分生理特点显示植物更加依靠稳定的水分供应来应对 极端干旱的环境条件，并且在蒸腾作用中形成了细胞水平上的生理适应策略．因此，保持地下水的稳定是维持绿洲前 沿天然胡杨林持续存在的关键因素．图3表1参21 关键词 胡杨；塔克拉玛干；水势；pV参数 CLC S792．110．1(245) Characteristics of Water Status in Populus euphratica Outside the Oases in the Taklamkan Desert LI Xiangyi ．LIN Lisha．ZHANG XimingZENG Fanjiang (Xinjiang Institute ofEcology and Geography，Chinese Academy ofSciences，Urumqi 830011，China) Abstract In the extremely arid area of the southern Taklamakan Desert in Xinjiang，NW China，the mean annual precipitation is less than 50 mm．Outside the fiver oases in this region，Populus euphratica Oliv．is a dominant woody plant in indigenous vegetation．The water status of P．euphratica was studied in the southern Taklamakan Desert．The results showed that with the stable soll water content in habitat resulting from permanent gmund water table．the water stress of P．euphratica was not severe and drought stress was not the main factor to threaten the long—term survive of P．euphratwa．The characteristics of water status in P．euphratica indicated that the plant depended mainly on constant sufficient water supply to cope with the ex— tremely drought environment at its growing sites．At the sa／ne time，this species developed its physiological adaptation at cell level in transpiration．Therefore，the key factor to guarantee a sustainable survival of P．euphratica in the peripheral area of the oases is to keep the groundwater table stable in different depths．Fig 3，Tab 1，Ref 21 Keywords Populus euphratic