Water use strategies of natural Pinus sylvestris var. Mongolica trees of different ages in Hulunbuir Sandy Land of Inner Mongolia, China, based on stable isotope analysis
Water use strategies of natural Pinus sylvestris var. Mongolica trees of different ages in Hulunbuir Sandy Land of Inner Mongolia, China, based on stable isotope analysis
复制标题
天然樟子松的水分利用策略
DOI：
10.1007/s00468-018-1691-2
复制
发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Li Dabo
中科院分区：
文献类型：
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作者：
Song Lining;Zhu Jiaojun;Li Mingcai;Zhang Jinxin;Li Dabo
关键信息不同年龄的天然樟子松在整个主要生长季节都持续使用浅水;因此，土壤浅层中的水分对维持樟子松的生存能力至关重要.桑迪的樟子松人工林在生长30-35年后，由于水分缺乏，经常发生枯死，而天然樟子松林在同一生长阶段保持健康。然而，天然樟子松的水分利用策略仍不清楚。为此，对10-20年、20-30年和30-50年生天然樟子松枝条木质部水、土壤水和地下水中的δ 2 H和δ 18 O进行了分析，以判别其水源。同时测定了针叶δ 13 C，以评价水分利用效率。结果表明，不同树龄的松树对同一深度土壤水分的利用程度不同。在生长季节（6月至8月），所有松树利用水从0至20厘米的土壤深度，无论土壤水分条件。在生长季末期（9月和10月），尽管0-20 cm土层的土壤水分含量较高，但不同年龄的松树在9月利用0-60 cm土层的水分，而在10月转向利用20-80 cm土层的水分。各年龄组松树针叶δ 13 C值在不同采样期间差异不显著，说明松树无论年龄大小，都能吸收足够的水分满足其对水分的需求。这些结果表明，在生长季节（6 - 8月），土壤浅层（0-20 cm）中储存的水分在支持树木蒸腾方面起着重要作用。因此，浅层土壤的稳定性对维持天然樟子松林的生存能力至关重要。
Key messageNatural Mongolian pine trees of different ages consistently use shallow water throughout the main growing season; therefore, water stored in the shallow soil layer is vital for maintaining their viability.AbstractMongolian pine (Pinus sylvestrisvar.mongolica) plantations in sandy regions often experience dieback after 30–35 years of growth due to water deficiency, whereas natural Mongolian pine forests remain healthy during the same growth stage. However, the water use strategies of natural Mongolian pines remains unclear. Therefore, δ2H and δ18O in twig xylem water, soil water and groundwater were analyzed in 10–20, 20–30 and 30–50-year-old natural Mongolian pine trees to identify their water sources. In addition, needle δ13C was measured simultaneously to assess water use efficiency. Results showed that pine trees of different ages utilized soil water from the same depth. During the growing season (June–August), all pine trees utilized water from 0 to 20 cm soil depth, regardless of the soil water condition. During the end of growing season (September and October), even though soil moisture content in the 0–20 cm depth was higher, pine trees of different ages utilized water from the 0–60 cm soil depth in September and switched to utilize water from the 20–80 cm soil depth in October. There were no significant differences in needle δ13C among the sampling dates for trees in each age group, indicating that pine trees can absorb sufficient water to satisfy their water requirements regardless of age. These findings suggest that water stored in the shallow soil layer (0–20 cm) plays an important role in supporting tree transpiration during the growing season (June–August). Therefore, the stability of shallow soil is vital for maintaining the viability of natural Mongolian pine forests.