Xu Manhou, Zhao Zitong, Zhou Huakun, Ma Li, Liu Xiaojiao
Institute of Geographical Science, Taiyuan Normal University, Jinzhong, China.
Key Laboratory of Restoration Ecology of Cold Area in Qinghai Province, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, China.
Front Plant Sci. 2022 May 9;13:860980. doi: 10.3389/fpls.2022.860980. eCollection 2022.
The effects of global warming have warmed the climate of the Qinghai-Tibetan Plateau (QTP) leading to changes in plant growth and soil nutrients in the alpine meadows. However, few studies have addressed the effects of warming on plant allometric growth and soil stoichiometry in these meadows on a long-term scale. Therefore, the effects of soil stoichiometry on plant allometric growth remain unclear under long-term warming in the alpine meadows. This study adopted infrared radiators to conduct an 8-year warming experiment in a permafrost region on the QTP starting in 2010, and surveyed growth indices of the plant community during the growing season. Soil organic carbon (C), total nitrogen (N), and total phosphorus (P) in an alpine meadow were measured. We initially learned that the aboveground part of the alpine meadow vegetation in the warming treatment changed from an isometric to an allometric growth pattern while the allometric growth pattern of the belowground part was further strengthened. Second, the contents of soil C, N, and P decreased at the 0-20 cm depth and increased at the 20-30 cm depth in warming. The ratios of soil C:N, C:P, and N:P showed increasing trends at different soil depths with artificial warming, and their amplitudes increased with soil depths. Warming promoted the migration of soil stoichiometric characteristics of C, N, and P to deep soil. Finally, the correlations of plant growth with soil stoichiometric characteristics were weakened by warming, demonstrating that the downward migration of soil stoichiometric characteristics to deep soil in warming had effects on the growth of vegetation in the alpine meadow. It concludes that the change in soil stoichiometric characteristics with soil depths promotes plant allometric growth in the alpine meadow under climate warming.
全球变暖的影响使青藏高原（QTP）气候变暖，导致高寒草甸植物生长和土壤养分发生变化。然而，很少有研究在长期尺度上探讨变暖对这些草甸植物异速生长和土壤化学计量的影响。因此，在高寒草甸长期变暖条件下，土壤化学计量对植物异速生长的影响仍不明确。本研究采用红外辐射器，于2010年开始在QTP的一个多年冻土区进行了为期8年的变暖实验，并在生长季调查了植物群落的生长指标。测量了高寒草甸土壤有机碳（C）、全氮（N）和全磷（P）。我们初步了解到，变暖处理下高寒草甸植被地上部分从等速生长模式转变为异速生长模式，而地下部分的异速生长模式则进一步增强。其次，变暖条件下，0-20厘米深度土壤C、N、P含量下降，20-30厘米深度土壤C、N、P含量上升。随着人工增温，不同土壤深度土壤C:N、C:P和N:P比值呈上升趋势，且增幅随土壤深度增加。变暖促进了土壤C、N、P化学计量特征向深层土壤的迁移。最后，变暖削弱了植物生长与土壤化学计量特征的相关性，表明变暖条件下土壤化学计量特征向深层土壤的下移对高寒草甸植被生长产生了影响。研究得出结论，在气候变暖条件下，土壤化学计量特征随土壤深度的变化促进了高寒草甸植物的异速生长。
