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林业科学 ›› 2018, Vol. 54 ›› Issue (7): 16-23.doi: 10.11707/j.1001-7488.20180702

• 论文与研究报告 • 上一篇    下一篇

北京山区侧柏利用水分来源对降水的响应

刘自强, 余新晓, 贾国栋, 李瀚之, 路伟伟, 侯贵荣   

  1. 北京林业大学水土保持国家林业局重点实验室 北京 100083
  • 收稿日期:2017-01-10 修回日期:2018-06-11 出版日期:2018-07-25 发布日期:2018-08-11
  • 基金资助:
    国家自然科学基金重点项目"基于稳定同位素的典型森林生态系统水、碳过程及其耦合机制研究"(41430747);青年科学基金项目"北京山区主要造林树种水分利用机制及其生理生态响应研究"(41401013);科技创新服务能力建设-协同创新中心-林果业生态环境功能提升协同创新中心(PXM2018_014207_000024)。

Response to Precipitation in Water Sources for Platycladus orientalis in Beijing Mountain Area

Liu Ziqiang, Yu Xinxiao, Jia Guodong, Li Hanzhi, Lu Weiwei, Hou Guirong   

  1. Key Laboratory of State Forestry Administration on Soil and Water Conservation, Beijing Forestry University Beijing 100083
  • Received:2017-01-10 Revised:2018-06-11 Online:2018-07-25 Published:2018-08-11

摘要: [目的]探究降水不足的北京山区降水量变化对侧柏利用水分来源的影响,为了解侧柏对土壤干旱胁迫的响应提供理论依据。[方法]2015年7月,测定侧柏枝条及各潜在水源的稳定氢氧同位素(18O/16O、2H/1H)比率,利用Iso-Source多元线性混合模型,计算2015年6月29日—7月1日3天不同降水梯度(A区:完全遮断自然降水,降水量0 mm;B区:遮挡自然降水的一半,降水量12.7 mm;C区:无遮挡自然降水,降水量25.4 mm;D区:将A区降水输入该区,形成双倍降水,降水量50.8 mm)下侧柏对各层土壤水和地下水的利用率。[结果]随降水量增加,侧柏表现出"二态"结构特征,其水分来源从深层逐渐向表层转移;A区侧柏主要吸收60~100 cm土层土壤水和地下水,利用率分别为31.5%和32.8%;B区侧柏与A区相似,对60~100 cm土层土壤水和地下水的利用率分别为28.1%和25.7%,对0~20、20~40和40~60 cm土层土壤水的利用率在15.4%左右;与B区相比,C区侧柏对60~100 cm土层土壤水和地下水的利用率有所减少,分别为19.8%和22.8%,对0~20和20~40 cm土层土壤水的利用率增加,分别为17.8%和22.9%;D区侧柏水分来源与C区相近,对0~20、20~40和60~100 cm土壤水和地下水都有利用,利用率为20.0%~25.2%。[结论]侧柏能根据水分条件调整对水源的利用率,这种适应水分环境的水分利用能力有利于侧柏度过极端干旱胁迫。

关键词: 侧柏, 降水梯度, 水分来源, 利用策略, 氢氧同位素, 北京山区

Abstract: [Objective]To explore the influence of precipitation on water sources for Platycladus orientalis in Beijing mountainous areas and to provide a theoretical basis for understanding the response of P. orientalis to soil drought stress.[Method]We determined the hydrogen and oxygen values of xylem and investigated the water sources of P. orientalis in different precipitation conditions(A:no precipitation, 0.0 mm; B:1/2 precipitation, 12.7 mm; C:natural precipitation, 25.4 mm, D:two times of precipitation, 50.8 mm) by Iso-Source model during the vigorous growing season.[Result]P. orientalis showed a "plasticity root system" structure. It absorbed water from deep to surface soil layer with the precipitation gradients. In treatment A, P. orientalis mainly absorbed water from 60-100 cm and groundwater; the utilization rate was 31.5% and 32.8%, respectively. Similarly, in treatment B, it obtained water from 60-100 cm and groundwater; the utilization rate was 28.1% and 25.7%, respectively. But in treatment C, P. orientalis absorbed water from layer of 60-100 cm and groundwater; the utilization rate was 19.8% and 22.8%, respectively. At the same time, it absorbed water from the surface 0-20 and 20-40 cm soil layer; the utilization rate was17.8% and 22.9%, respectively. The water source of P. orientalis in treatment D was 0-20, 20-40, and 60-100 cm soil layer and groundwater with the utilization rate in the range of 20%-25.2%.[Conclusion]P. orientalis can adjust water source and its utilization ratio according to water conditions.

Key words: Platycladus orientalis, precipitation gradient, water source, utilization strategy, hydrogen and oxygen isotopes, Beijing mountain area

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