青海湖流域具鳞水柏枝植物水分利用氢同位素示踪研究  

Study on plant water use in Myricaria squamosa with stable hydrogen isotope tracer in Qinghai Lake basin

作　　者：赵国琴[1,2] 李小雁[1,2] 吴华武[2] 张思毅[2] 李广泳[2] 

机构地区：[1]地表过程与资源生态国家重点实验室,北京100875 [2]北京师范大学资源学院,北京100875

出　　处：《植物生态学报》2013年第12期1091-1100,共10页Chinese Journal of Plant Ecology

基　　金：国家自然科学基金重点项目(4113-0640);长江学者和创新团队计划"土壤水文与土壤侵蚀"(批准号:IRT1108);中央高校基本科研业务费专项资助

摘　　要：具鳞水柏枝(Myricaria squamosa)是我国高寒地区广泛分布的优势河谷灌木,具有维持河谷湿地系统稳定的功能。然而,目前国内外有关具鳞水柏枝水分利用来源的定量研究很少。该文运用氢稳定同位素示踪方法,分析了青海湖流域具鳞水柏枝茎(木质部)水和潜在水源(地下水、河水和土壤水)的氢稳定同位素比率(δD)的季节变化,发现具鳞水柏枝在不同水文环境下的植物水分利用来源有明显差异。研究结果表明,生长在河岸边的具鳞水柏枝在6、7月主要利用地下水与河水,分别占其所利用水分的89%、86%和55%、65%,8月主要利用0–20 cm土层的土壤水,9月水源不详。生长在离河岸约100 m处的具鳞水柏枝在6月主要利用地下水与河水(91%、70%),在7–9月以0–60 cm土层的土壤水为主要水源。这表明生长在河岸边的具鳞水柏枝对地下水和河水的依赖程度较高,而距离河岸约100 m时对土壤水的利用量较多,反映出生长在不同生境中的具鳞水柏枝对特定水分条件的特殊适应结果。Aims Little study has been conducted to quantify plant water sources for Myricaria squamosa, which is a domi- nant alpine riparian shrub in the Qinghai Lake basin and plays a key role in maintaining riverine wetland system. The objective of this study was to quantify water sources for M. squamosa growing under different hydrological conditions.Methods We collected the water samples from the xylem of M. squamosa, groundwater, river, and soils in the Qinghai Lake basin from June through September, and analyzed the seasonal variation of hydrogen stable isotope ratio（δD） in the xylem and potential water sources using stable hydrogen isotope tracer method. We then com- pared the differences in water sources for M. squamosa growing under two contrasting hydrological conditions. Important findings Myricaria squamosa plants growing on the river bank mainly used groundwater and water from the river stream in June and July, with groundwater contributing up to 89% of water use in June and 55% in July and river stream contributing up to 86% in June and 65% in July, respectively; whilst in August, they used water mainly from the 0–20 cm soil layer; the water source in September was identifiable. In contrast, Myricaria squamosa plants growing approximately about 100 m away from the river bank mainly accessed the groundwater and river water in June（91% and 70%, respectively）, and used water from the 0–60 cm soil layer during the rainy months July, August and September. Results suggest that M. squamosa plants on the river bank use mainly groundwater and river water; soil water was more important for those far away from the river bank. These are resulted from the re- sponses of this shrub species to specific water conditions when growing under contrasting water regimes.

关 键 词：氘同位素 具鳞水柏枝 植物水分 青海湖流域 河谷灌木 

分 类 号：Q945[生物学—植物学]