Effect of Drought and Topographic Position on Depth of Soil Water Extraction of Pinus sylvestris L. var. mongolica Litv. Trees in a Semiarid Sandy Region, Northeast China
Effect of Drought and Topographic Position on Depth of Soil Water Extraction of Pinus sylvestris L. var. mongolica Litv. Trees in a Semiarid Sandy Region, Northeast China
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干旱和地形对樟子松土壤水分提取深度的影响
DOI：
10.3390/f10050370
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发表时间：
2019-04
期刊：
影响因子：
2.9
通讯作者：
Liu Jianhua
中科院分区：
文献类型：
--
作者：
Song Lining;Zhu Jiaojun;Zhang Jinxin;Zhang Ting;Wang Kai;Wang Guochen;Liu Jianhua
干旱和地形位置是影响东北半干旱沙区树木生长和存活的最重要因素。然而，人们对树木如何通过改变土壤水分提取深度来应对干旱和地形位置的关系知之甚少。因此，通过比较不同深度土壤水分和干湿期地下水的δ2H和δ18O稳定同位素，对生长在沙丘顶部和底部的33年蒙松（Pinus sylvestris L. var. mongolica Litv.）树木进行了水源鉴定。同时测定针碳同位素组成（δ13C），评价水分利用效率。结果表明，枯水期土壤水分较低时，上层树木利用40 ~ 300 cm土壤水分，下层树木利用40 ~ 300 cm土壤水分，也可能利用地下水。湿润期0 ~ 100 cm土壤水分较高时，树木的主要水分来源为顶部和底部。干期针叶δ13C显著高于湿期。这些结果表明，在干旱条件下，顶部和底部树木都调节了对深层水源的吸收，提高了水分利用效率。此外，在干旱时期，与底部树木相比，顶部树木使用的水源较浅，同时针尖δ13C显著较高，表明底部树木在干旱条件下通过吸收较深的水（可能是地下水）来相对更多地使用水。因此，在极端干旱年份，由于土壤吸水性较浅，水分限制增加，顶部的蒙松更容易发生枯死。然而，在极端干旱年份，地下水位的急剧下降对底部蒙松的生长和生存产生了强烈的负面影响，因为它们利用了更深的水源（可能是地下水）。
Drought and topographic position are the most important factors influencing tree growth and survival in semiarid sandy regions of Northeast China. However, little is known about how trees respond to drought in combination with topographic position by modifying the depth of soil water extraction. Therefore, we identified water sources for 33-year-old Mongolian pine (Pinus sylvestris L. var. mongolica Litv.) trees growing at the top and bottom of sand dunes by comparing stable isotopes δ2H and δ18O in twig xylem water, soil water at various depths and groundwater during dry and wet periods. Needle carbon isotope composition (δ13C) was simultaneously measured to assess water use efficiency. Results showed that when soil moisture was low during the dry period, trees at the top used 40–300 cm soil water while trees at the bottom utilized both 40–300 cm soil water and possibly groundwater. Nevertheless, when soil moisture at 0–100 cm depth was higher during the wet period, it was the dominant water sources for trees at both the top and bottom. Moreover, needle δ13C in the dry period were significantly higher than those in the wet period. These findings suggested that trees at both the top and bottom adjust water uptake towards deeper water sources and improve their water use efficiency under drought condition. Additionally, during the dry period, trees at the top used shallower water sources compared with trees at the bottom, in combination with significantly higher needle δ13C, indicating that trees at the bottom applied a relatively more prodigal use of water by taking up deeper water (possibly groundwater) during drought conditions. Therefore, Mongolian pine trees at the top were more susceptible to suffer dieback under extreme dry years because of shallower soil water uptake and increased water restrictions. Nevertheless, a sharp decline in the groundwater level under extreme dry years had a strong negative impact on the growth and survival of Mongolian pine trees at the bottom due to their utilization of deeper water sources (possibly groundwater).
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影响因子：
6.2
作者：
Song Lining;Zhu Jiaojun;Li Mingcai;Zhang Jinxin;Zheng Xiao;Wang Kai
通讯作者：
Wang Kai
影响因子：
1
作者：
N. Orlowski;H. Frede;N. Brüggemann;L. Breuer
通讯作者：
N. Orlowski;H. Frede;N. Brüggemann;L. Breuer
DOI：
--
发表时间：
2020-06
期刊：
--
影响因子：
--
作者：
Quevedo Amaya;Yeison Mauricio
通讯作者：
Quevedo Amaya;Yeison Mauricio
DOI：
10.1007/s00468-013-0928-3
发表时间：
2014-02
期刊：
Trees
影响因子：
--
作者：
H. Su;Yonggeng Li;Wei Liu;Hong Xu;O. Sun
通讯作者：
H. Su;Yonggeng Li;Wei Liu;Hong Xu;O. Sun
影响因子：
2.7
作者：
Hartman G;Danin A
通讯作者：
Danin A