2014年浑善达克沙地黄柳生长季水分来源同位素示踪研究

黄柳是我国内蒙古东部和辽宁西部沙丘上广泛分布的多年生灌木,是极佳的固沙树种.通过利用氢同位素示踪方法,测定了2014年浑善达克沙地黄柳生长季茎干水与潜在水源(降水、土壤水、地下水)氢同位素比率δD值,并利用多源线性混合模型IsoSource,计算了黄柳对各潜在水源的利用比例.结果表明:在5月黄柳80％以上利用120 ～ 160 cm土壤水和地下水;6月主要吸收0～40 cm土壤水;7月主要吸收120～160 cm土壤水;8月以地下水为主要水源,利用率为82％.这表明生长在不同季节的黄柳对于各潜在水源的利用有特定的适应结果,同时也说明荒漠灌木可以通过自身的调节朝着最优的方向发展,实现最大限度的水分利用.

Water Sources in Growing Season of Salix gordejevii in the Otindag Sandy Land Traced by Stable D Isotope in 2014

Salix gordejevii is a widely-distributed perennial shrub species over the dunes in east Inner Mongolia and west Liaoning Province,China,and it is an excellent sand-fixing shrub species.However,there were very few studies about water sources closely related to the growth of S.gordejevii in both China and foreign countries.In this study,the hydrogen isotope tracer method was used to measure the growth of S.gordejevii in the growing season of 2014,branch stem water potential,water (precipitation,groundwater and soil moisture) regime and values of hydrogen stable isotope ratio (δD) in the Otindag Sandy Land,and the multi-source linear mixed model Iso Source model was used to calculate the proportions of potential water sources for the growth of S.gordejevii.The results showed that over 80％ water used by S.gordejevii was soil moisture and groundwater in depth of 120-160 cm in May.S.gordejevii absorbed mainly soil moisture of 0-40 cm in depth in June and mainly that of 120-160 cm in depth in July.In August,groundwater was the main water source,and its utilization rate was as high as 82％.These revealed that the potential water sources for the growth of S.gordejevii were different in different seasons,and also suggested that such desert shrub could adapt the optimal water sources through their own adaptive capability to achieve the maximum water use.