Qin Yanyan, Liu Wei, Zhang Xiaofang, Adamowski Jan F, Biswas Asim
Key Laboratory of Land Surface Process and Climate Change in Cold and Arid Regions, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, China.
Key Laboratory of Ecohydrology of Inland River Basin, Northwest Institution of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, China.
Front Plant Sci. 2022 Feb 24;13:814059. doi: 10.3389/fpls.2022.814059. eCollection 2022.
As an individual plant species can develop its own leaf stoichiometry to adapt to environmental changes, this stoichiometry can provide critical information about a plant species' growth and its potential management in the ecosystem housing it. However, leaf stoichiometry is largely undocumented in regions with large environmental changes arising from differences in elevation. The leaf stoichiometry of L., a major alpine shrub playing an important role in supporting ecosystem functions and services in China's Qilian Mountains (Northeast Qinghai-Tibetan Plateau), was investigated at different elevations (2,400, 2,600, 2,800, 3,000, 3,200, 3,500, and 3,800 m). At each elevation, leaf elemental (C, N, and P) concentrations were measured in leaves sampled from three plots (10 × 10 m), and edaphic properties were assessed in nine quadrats (1 × 1 m, three quadrats per plot). Temperature and precipitation were calculated using an empirical formula. Maximum and minimum leaf carbon (C) concentrations ([C] ) of 524 ± 5.88 and 403 ± 3.01 g kg were measured at 2,600 and 3,500 m, respectively. Leaf nitrogen (N) concentration ([N] ) showed a generally increasing trend with elevation and peaked at 3,500 m (27.33 ± 0.26 g kg). Leaf phosphorus (P) concentration ([P] ) varied slightly from 2,400 to 3,200 m and then dropped to a minimum (0.60 ± 0.10 g kg) at 3800 m. The [C] :[N] , [C] :[P] , and [N] :[P] varied little from 2,400 to 3,000 m but fluctuated somewhat at higher elevations. The main factors affecting leaf stoichiometry were soil organic C, pH, and soil total P, and the main limiting element for the growth of in the study area was P. In conclusion, changes in elevation affected leaf stoichiometry of mainly due to altered soil properties, and addressing phosphorus limitation, especially at higher elevations mainly due to losses caused by high precipitation and sparse vegetation, is a key measure to promote growth in this region.
由于单个植物物种可以形成自身的叶片化学计量比以适应环境变化，这种化学计量比能够提供有关该植物物种生长及其所在生态系统中潜在管理方面的关键信息。然而，在因海拔差异导致环境变化较大的地区，叶片化学计量比在很大程度上尚无记录。对中国祁连山（青藏高原东北部）一种在支持生态系统功能和服务方面发挥重要作用的主要高山灌木——高山柳（Salix cupularis）在不同海拔（2400、2600、2800、3000、3200、3500和3800米）的叶片化学计量比进行了调查。在每个海拔高度，从三个样地（10×10米）采集的叶片中测量叶片元素（碳、氮和磷）浓度，并在九个样方（1×1米，每个样地三个样方）中评估土壤性质。利用经验公式计算温度和降水量。分别在2600米和3500米处测得高山柳叶片碳（C）浓度（[C]max）的最大值和最小值为524±5.88克/千克和403±3.01克/千克。叶片氮（N）浓度（[N]）总体上随海拔升高呈增加趋势，并在3500米处达到峰值（27.33±0.26克/千克）。叶片磷（P）浓度（[P]）在2400米至3200米之间变化较小，然后在3800米处降至最低值（0.60±0.10克/千克）。[C]max:[N]、[C]max:[P]和[N]:[P]在2400米至3000米之间变化不大，但在较高海拔处有所波动。影响高山柳叶片化学计量比的主要因素是土壤有机碳、pH值和土壤全磷，研究区域内高山柳生长的主要限制元素是磷。总之，海拔变化影响高山柳叶片化学计量比主要是由于土壤性质改变，解决磷限制问题，特别是在较高海拔处主要因高降水量和植被稀疏导致的磷流失问题，是促进该地区高山柳生长的关键措施。
