Scholarlink

Background <p>The southwestern Tibetan Plateau (TP) is characterized by cold and dry alpine grasslands, yet how plants and soil nitrogen cycles adapt to conditions that are drier and colder than other parts of the TP remain unclear. We measured δ<sup>13</sup>C and δ<sup>15</sup>N in <i>Astragalus</i>, a widespread N-fixing legume, and soils along a 3500–5000&#xa0;m transect in the southwestern TP.</p> Results <p>Plant δ<sup>13</sup>C and inferred intrinsic water-use efficiency (iWUE, 85.6–114.2&#xa0;μmol CO<sub>2</sub> mol<sup>−1</sup> H<sub>2</sub>O) were primarily controlled by growing-season temperature (GST), with SEM showing a significant direct effect of GST on iWUE (standardized path coefficient = 0.45, <i>p</i> &lt; 0.01). Conversely, soil δ<sup>15</sup>N (2.8‰ to 11.3‰) was negatively associated with mean annual precipitation (MAP; R<sup>2</sup> = 0.26, <i>p</i> &lt; 0.01), while plant–soil Δ<sup>15</sup>N was mainly driven by mean annual precipitation (MAP, R<sup>2</sup> = 0.24, <i>p</i> &lt; 0.01). These Δ<sup>15</sup>N patterns may reflect shifts in the relative contribution of atmospheric N<sub>2</sub> fixation and soil N uptake by <i>Astragalus</i>, as inferred from isotopic evidence.</p> Conclusions <p>These results suggest potential responses of plant carbon–water coupling and isotope-inferred N acquisition under future warming and drying in high-elevation ecosystems.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Climatic controls on water-use efficiency and nitrogen acquisition of Astragalus on southwestern Tibetan Plateau

  • 期刊论文

  • 出版模式：

    开放获取

  • 发表日期：

    2026年7月14日

查看全文
  • Songbo Qu,
  • Xu-Ri,
  • Jiaoneng Yu,
  • Ribu Shama,
  • Haojing Lei,
  • Tian-Liang,
  • Sainbuyan Bayarsaikhan,
  • Azzaya Jukov,
  • Munkhbat Tsendeekhuu,
  • Gundegmaa Vanjil,
  • Almaz Borjigidai

摘要

Background

The southwestern Tibetan Plateau (TP) is characterized by cold and dry alpine grasslands, yet how plants and soil nitrogen cycles adapt to conditions that are drier and colder than other parts of the TP remain unclear. We measured δ13C and δ15N in Astragalus, a widespread N-fixing legume, and soils along a 3500–5000 m transect in the southwestern TP.

Results

Plant δ13C and inferred intrinsic water-use efficiency (iWUE, 85.6–114.2 μmol CO2 mol−1 H2O) were primarily controlled by growing-season temperature (GST), with SEM showing a significant direct effect of GST on iWUE (standardized path coefficient = 0.45, p < 0.01). Conversely, soil δ15N (2.8‰ to 11.3‰) was negatively associated with mean annual precipitation (MAP; R2 = 0.26, p < 0.01), while plant–soil Δ15N was mainly driven by mean annual precipitation (MAP, R2 = 0.24, p < 0.01). These Δ15N patterns may reflect shifts in the relative contribution of atmospheric N2 fixation and soil N uptake by Astragalus, as inferred from isotopic evidence.

Conclusions

These results suggest potential responses of plant carbon–water coupling and isotope-inferred N acquisition under future warming and drying in high-elevation ecosystems.