Stable isotopic observation of water use sources of Pinus sylvestris var. mongolica in Horqin Sandy Land, China
Stable isotopic observation of water use sources of Pinus sylvestris var. mongolica in Horqin Sandy Land, China
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DOI：
10.1007/s00468-013-0873-1
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发表时间：
2013-04
期刊：
影响因子：
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通讯作者：
Y. F. Wei;J. Fang;S. Liu;X. Y. Zhao;S. G. Li
中科院分区：
文献类型：
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作者：
Y. F. Wei;J. Fang;S. Liu;X. Y. Zhao;S. G. Li
自20世纪50年代末以来，蒙古松(Pinus sylvestrisvar。在华北干旱、半干旱地区，广泛种植蒙古沙（mongolica），用于植被恢复。利用20世纪80年代初在科尔沁沙地东南缘沙丘上种植的蒙松的降水、土壤水分和木质部水分的稳定同位素信号，确定了蒙松的吸水量来源。(1)木质部水分的18o同位素组成不具有明显的季节性，表明树木使用了相对稳定的水源；(2)松树的水源主要来自20 ~ 60 cm的土壤深度（本研究取样深度达60 cm），当土壤湿度极低时，树木可能会利用地下水；(3)固定沙丘顶部松树与沙丘间低地松树的水源利用差异不大，但两者的高程差在3 ~ 8 m之间。研究结果表明，蒙松在沙地生境生长需要获得相对可靠和稳定的水源，雨水及时补给到树木根部深度是避免和/或减少缺水导致的树木退化的必要条件。
Since the late 1950s, Mongolian pine (Pinus sylvestrisvar.mongolica) has been widely planted for vegetation restoration in arid and semi-arid areas in North China. We used stable isotope signals from precipitation, soil water, and xylem water of Mongolian pine trees, which were planted in early 1980s on sand dunes in the east-southern margin of Horqin Sandy Land, to identify water uptake sources of this tree. (1) Stable18O isotope composition of the xylem water exhibited little seasonality, suggesting that the trees use a relatively stable water source; (2) the water source of the pine trees primarily came from a soil depth of 20–60 cm (sampling depth up to 60 cm in this study) and the trees might use groundwater when soil moisture became extremely low; and (3) there was not much difference in water sources used by the pine trees grown at the top of the fixed dune and in the inter dune lowland, although these two sites had 3–8 m elevation difference. This study suggests that it is critical for Mongolian pine trees to access relatively reliable and stable water sources to grow in sandy land habitats, and timely recharging of rainwater to the trees’ rooting depth is requisite for avoiding and/or reducing their degradation caused by water shortage.