新疆准东荒漠区5种典型植物水分来源

Water Sources of Five Typical Plant Species in Desert in the East Junggar Basin,Xinjiang

水是植物的主要限制性因子之一,不同生活型植物水分来源不同。运用稳定同位素示踪技术,对准东荒漠区5种典型植物梭梭（Haloxylon ammodendron）、白梭梭（H.persicum）、刺旋花（Convolvulus tragacanthoides）、琵琶柴（Reaumuria soongonica）和盐生假木贼（Anabasil salsa）的小枝木质部水及其潜在水源的氧稳定同位素（δ18O的组成进行测定,采用Iso Source模型分析这5种植物对各潜在水源的利用比例,相似性比例指数（PS指数）定量分析不同植物间水分利用关系。结果表明：5种植物主要利用土壤水,但其吸水层位不同,梭梭和白梭梭主要利用深层土壤水（140-200 cm）,利用比例分别为73%-87%和43%-74%,吸水层位于140-160 cm;琵琶柴主要利用浅层土壤水（0-80 cm）,利用比例为49%-85%,吸水层位于60-80 cm;盐生假木贼和刺旋花主要利用浅层土壤水（0-60 cm）,利用比例分别为80%-91%和24%-79%,盐生假木贼吸水层位于20-40 cm,刺旋花吸水层位于40-60cm。梭梭和白梭梭、盐生假木贼和刺旋花两两存在水源竞争的现象。此研究为荒漠地区生态恢复与重建以及对植物在干旱环境下的适应性探索提供参考依据。

In desert environment,water is the principal factor affecting plant distribution,and the plants with different life forms have different water sources. As hydrogen stable isotopes are prone to fractionation in salt-tolerant and drought-tolerant plants,so,in this study,oxygen isotope ratios（ δ18 O） were measured for xylem water of five typical plant species,soil moisture in different soil layers and groundwater in the east Junggar Basin. The five typical plant species were Haloxylon ammodendron,H. persicum,Convolvulus tragacanthoides,Reaumuria soongonica and Anabasis salsa respectively. The Iso Source model was used to calculate the possible ranges of potential water sources used by the five typical plant species. The proportional similarity index（ SPI） was used to analyze the water use relationship among different plant species. The result showed that the five typical plant species used mainly soil water but had different water uptake soil layers. H. ammodendron and H. persicum used mainly deep soil water（ 140-200 cm in depth）,their soil water use proportions were 73%-87% and 43%-74% respectively,and the water uptake soil depthvaried in a range of 140-160 cm. R. soongonica used mainly soil water in depth of 0-80 cm,its soil water use proportion varied in a range of 49%-85%,and the water uptake soil depth was 60-80 cm. A. salsa and C. tragacanthoides used mainly soil water in depth of 0-60 cm,their soil water use proportions were 80%-91%and 24%-79%,and the water uptake soil depths were 20-40 cm and 40-60 cm,respectively. There were water use competition between H. ammodendron and H. persicum and between A. salsa and C. tragacanthoides. This study could help us to know more about the adaption of plant species in desert environment.