自然状况下头状沙拐枣对水分条件变化的响应  

THE RESPONSES OF CALLIGONVM CAPUT-MEDUSAE TO CHANGES OF WATER CONDITIONS UNDER NATURAL ENVIRONMENT

作　　者：李向义[1] Frank M.THOMAS Andrea FOETZKI 曾凡江[1] 张希明[1] 何兴元[3] 

机构地区：[1]中国科学院沈阳应用生态研究所,沈阳110016 [2]德国哥廷根大学生态与生态系统研究所,哥廷根d37073 [3]中国科学院新疆生态与地理研究所,乌鲁木齐830011

出　　处：《植物生态学报》2003年第4期516-521,共6页Chinese Journal of Plant Ecology

基　　金：中国-欧盟合作项目(ERBIC18CT980275);中国科学院重大项目(KZ951-B1-231-02-02);国家重点基础研究发展规划项目(G199904350504);新疆"山川秀美"计划(980108001-04-01);中国科学院创新领域前沿项目(KZCX-XJLQ-05)

摘　　要：对塔克拉玛干沙漠南缘沙漠-绿洲过渡带前沿人工植被头状沙拐枣(Calligonum caput-medusae)水分关系的研究表明:头状沙拐枣在生长季节中一直保持着正的膨压,水分亏缺的发展并不严重,植被所受水分胁迫在正常范围内,因而在现存条件下干旱引起的水分胁迫不足以威胁植被的存在。在生长进程中,随着环境胁迫的加剧,头状沙拐枣依然维持了比较高的水势和渗透势,实验结果也显示植株体内可溶性物质(N_sDM)的累积程度并没有升高,因而其生理过程仍然在比较宽松的环境中进行。相对含水量(RWC_p)在生长季节一直保持很高的水平,这对植株保持体内水分防止水分过度损失有利。头状沙拐枣在干旱胁迫下表现出的这些生理特点说明,植物对干旱环境的生理适应类型属于抵抗型。在叶水平上植株对干旱胁迫的水分生理适应主要表现为质外体水比例的增高,细胞壁弹性的增加,持续较高的相对含水量(RWC_p)以及灌水后RWC_p和枝条水分比值(WC_(sat))的增加上。夏季的引洪灌溉有助于头状沙拐枣水分状况的恢复,并很可能是植被免于严重水分胁迫的原因之一。In the Taklamakan desert region, water is the most important limiting factor to influence plant growth and distribution. The study of water relations is necessary to provide an ecological basis for the sustainable management of the vegetation at the transition between oasis and sandy desert to protect oasis environments . At the same time, the study also provided theory about how to use the limited water resources to regenerate vegetation, In the southern fringe of the Taklamakan desert Calligonwn caput-medusae Schrenk. (Polygo-naceae) is a introduced species which serves as important shelter vegetation against sand drift at the foreland of the oasis. We investigated: 1) the degree to which plants suffered water stress during flooding conditions in summer; 2) the adaptability of physiological characters in water relations to this extreme environment; 3) the effect of irrigation on water status of vegetation (utilizing summer flooding). From April to October in 1999, around the 20th of each month, the predawn water potential (ψp; between 5:00 and 6:00) and the afternoon water potential (ψ. between 13:00 and 14:00) were measured using pressure chambers on six plants with three measurements per plant. Following the measurements of water potential, the pressure and volume (PV) curves from three or four samples were established. The results showed C. caput-medusae kept positive turgor during the growing season. Development of water deficit was not severe and the water stress that plants suffered was still in the normal range. Thus, the water stress induced by drought is not severe enough to threaten the survival of the artificial vegetation. During the growing season, C. caput-medusae still maintained relatively high water potential and osmotic potential as the environmental stress increased. At the same time, no experimental evidence indicated that the accumulation of solute (NSDM) reached high levels either. Therefore, the physiological process of plants still worked in normal conditions. The relative water conten

关 键 词：自然状况 头状沙拐枣 水分条件 干旱胁迫 水势 灌溉效果 

分 类 号：Q945[生物学—植物学]