Soil Moisture and Soluble Salt Content Dominate Changes in Foliar delta C-13 and delta N-15 of Desert Communities in the Qaidam Basin, Qinghai-Tibetan Plateau

文献类型： 外文期刊

第一作者： Niu, Weiling

作者： Niu, Weiling;Chen, Hui;Chen, Hui;Wu, Jianshuang;Wu, Jianshuang

作者机构：

关键词： carbon isotopic composition; environmental gradients; nitrogen isotopic composition; nitrogen utilization strategy; water use efficiency

期刊名称：FRONTIERS IN PLANT SCIENCE （ 影响因子：5.754； 五年影响因子：6.612 ）

ISSN： 1664-462X

年卷期： 2021 年 12 卷

页码：

收录情况： SCI

摘要： Changing precipitation and temperature are principal drivers for nutrient cycling dynamics in drylands. Foliar isotopic carbon (C) and nitrogen (N) composition (delta C-13 and delta N-15) are often used to describe the plant's water use efficiency and nitrogen use strategy in plant ecology research. However, the drivers and mechanisms under differential foliar delta C-13 and delta N-15 among plant species and communities are largely unknown for arid high-elevation regions. This study collected 462 leaf samples of ten top-dominant plant species (two or three replicates per species) across 16 sites in 2005 and 2010 to measure the community-weighted means (CWMs) of foliar delta C-13 and delta N-15, northeastern Qaidam Basin, Qinghai-Tibetan Plateau. Our results showed that the CWM of foliar delta N-15 was higher in 2005 than in 2010 and was lower in the warm-dry season (July and August) than the cool-wet one (June and September) in 2010. Similarly, the CWM of foliar delta C-13 was higher in 2005 than in 2010, but no difference between warm-dry and cool-wet seasons in 2010. C-4 plants have higher delta C-13 and generally grow faster than C-3 species under warm-wet weathers. This might be why the CWM of foliar delta C-13 was high, while the CWM of foliar delta N-15 was low in the wet sampling year (2010). The general linear mixed models revealed that soil moisture was the most critical driver for the CWM of foliar delta N-15, which explained 42.1% of the variance alone. However, the total soluble salt content was the crucial factor for the CWM of foliar delta C-13, being responsible for 29.7% of the variance. Growing season temperature (GST) was the second most vital factor and explained 28.0% and 21.9% of the variance in the CWMs of foliar delta N-15 and delta C-13. Meanwhile, remarkable differences in the CWMs of foliar delta N-15 and delta C-13 were also found at the species level. Specifically, Kalidium gracile and Salsola abrotanoides have higher foliar delta N-15, while Ephedra sinica and Tamarix chinensis have lower foliar delta N-15 than other species. The foliar delta C-13 of Calligonum Kozlov and H. ammodendron was the highest among the ten species. Except for the foliar delta C-13 of E. sinica was higher than Ceratoide latens between the two sampling years or between the cool-wet and warm-dry seasons, no significant difference in foliar delta C-13 was found for other species. Overall, the CWMs of foliar delta N-15 and delta C-13 dynamics were affected by soil properties, wet-dry climate change, and species identity in high-elevation deserts on the Qinghai Tibetan Plateau.

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