干旱区研究 ›› 2024, Vol. 41 ›› Issue (1): 60-70.doi: 10.13866/j.azr.2024.01.06 cstr: 32277.14.AZR.20240106

• 水土资源 • 上一篇    下一篇

微地形对高寒固沙植物水分利用特征的影响

范明彦1(),田丽慧1(),周海2   

  1. 1.青海大学省部共建三江源生态与高原农牧业国家重点实验室,青海 西宁 810016
    2.中国科学院西北生态环境资源研究院,甘肃 兰州 730000
  • 收稿日期:2023-07-11 修回日期:2023-09-13 出版日期:2024-01-15 发布日期:2024-01-24
  • 作者简介:范明彦(1999-),女,硕士研究生,研究方向为沙地生态水文. E-mail: fanmy191120@126.com
  • 基金资助:
    中国科学院西部青年学者项目(2021_1_1);国家自然科学基金(41961017);青海大学省部共建三江源生态与高原农牧业国家重点实验室开放课题(2019_KF_003)

Effects of micro-topography on water use characteristics of alpine sand-fixing plants

FAN Mingyan1(),TIAN Lihui1(),ZHOU Hai2   

  1. 1. State Key Laboratory of Plateau Ecology and Agriculture, Qinghai University, Xining 810016, Qinghai, China
    2. Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, Gansu, China
  • Received:2023-07-11 Revised:2023-09-13 Published:2024-01-15 Online:2024-01-24

摘要:

水是植物生存最主要的限制因子,对沙区植物水分利用的研究已成为沙地生态保护和植被恢复的关键。本文以青海湖湖东沙地3种典型固沙植物——樟子松、小叶杨、沙棘为研究对象,基于氢氧稳定同位素技术(δ18O和δD),结合IsoSource模型,对微地形影响下的各潜在水源(不同层次的土壤水)及植物主要水分来源进行分析。研究结果表明:(1)土壤含水量具有微地形差异,表现在迎风坡低地土壤含水量高于沙丘顶部和迎风坡中部,且9月土壤含水量处在最高值。(2)木质部水的δ18O值在不同微地形条件下具有树种差异性,樟子松在迎风坡低地的δ18O值最小,而沙棘和小叶杨在迎风坡中部的δ18O值最小。(3)不同植物的主要水分来源具有较为明显的季节差异,6月樟子松和沙棘在不同微地形条件下均以深层土壤水为主要水分来源,而小叶杨在沙丘顶部主要利用深层土壤水,在迎风坡中部和低地对中层土壤水的利用较大,但随着降水量的增加,9月各树种转而主要利用浅层和中层土壤水。总而言之,高寒沙地固沙植物的水分利用模式受微地形条件的影响,且不同物种对降水表现出不同程度的响应。

关键词: 高寒沙地, 稳定同位素, 微地形, 植物水分来源, IsoSource模型

Abstract:

Water is the most critical limiting factor for plant survival, and the study of water utilization in desert plants has become the key to ecological protection and vegetation restoration programs. This study focused on three typical sand-fixing plants: Pinus sylvestris, Populus simonii, and Hippophae rhamnoides, in the sandy land on the east shore of Qinghai Lake, as the research material. The potential water source (varying levels of soil water) and the primary water sources for plants under the influence of micro-topography were analyzed by hydrogen and oxygen stable isotope technology (δ18O and δD) and the IsoSource isotope mixing model. The results show that: (1) the soil water content demonstrated micro-topography-based differences, which manifested as the soil water content on the windward slope being higher than that on the top of the sand dunes and the middle of the windward slope and the soil water content was at its highest in September. (2) the δ18O value of the xylem water varied in the tree species under different micro-topographic conditions. The δ18O values of P. sylvestris in the lowland of the windward slope were the lowest, while those of H. rhamnoides and P. simonii were the least in the middle of the windward slope. (3) marked seasonal variations were observed in the primary sources of water for different plants. In June, P. sylvestris and H. rhamnoides used deep soil water as the major source under varied micro-topographic conditions, while P. simonii mainly used deep soil water at the top of sand dunes. The soil water of the middle-layer was utilized more in the middle and lowlands of the windward slope. Still, with the increase of precipitation, various tree species turned to mainly using the shallow and middle soil water in September. In summary, the water use patterns of sand-fixing plants in the alpine sandy land were influenced by micro-topographic conditions, and varying species showed different degrees of response to precipitation.

Key words: alpine sandy land, stable isotope, micro-topography, plant water source, IsoSource model