College of Earth Sciences, Jilin University, Changchun, Jilin, China.
Key Laboratory of Mineral Resources Evaluation in Northeast Asia, Ministry of Land and Resources, Changchun, Jilin, China.
PLoS One. 2020 Dec 1;15(12):e0243172. doi: 10.1371/journal.pone.0243172. eCollection 2020.
Leymus chinensis (L. chinensis) is the dominant plant in the eastern margins of the Eurasian temperate grasslands. It is a very robust species, exhibiting good saline-alkali resistance and stabilizing soil. In this study, 67 soil samples and L. chinensis were collected in western Jilin province, China. The contents of N, P, K, S, Mn, Fe, Zn, Cu and Na were measured, revealing that the growth of L. chinensis was mainly restricted by N based on the stoichiometric N: P ratios of plant. Furthermore, path analysis indicated that N was significantly correlated with K, S, Cu, and Zn. Imbalances in the homeostasis of these four elements may thus constrain N. The homeostasis index of Cu (HCu) in sites with 100%-70% of vegetation cover was only 0.79, it was classified as a sensitive element. However, K, S and Zn, whose concentrations in L. chinensis were significantly related to those of N, exhibited no homeostatic characteristics. These results suggest that when seeking to treat saline-alkali stress, it is important to add fertilizers containing K, S, and Zn to avoid growth limitation. Na+, an ion associated with high soil alkalinity, exhibited weak homeostasis in L. chinensis even in sites with only 40%-10% of vegetation cover. When soil Na exceeded 16000 mg/kg, the homeostasis mechanism of L. chinensis appeared to be overwhelmed, resulting in rapid and probably harmful accumulation of Na. Proper control of N content can alleviate the toxicity of Na stress in L. chinensis and enhance its Na tolerance. Together, these results suggest that combined fertilization with N, K, S, Zn and Cu should be applied to improve grasslands growth. The results of this study can provide a reference basis for sustainable grassland management.
赖草是欧亚温带草原东缘的优势种植物，具有良好的耐盐碱性和土壤稳定性。本研究在中国吉林省西部采集了 67 个土壤样本和赖草。测量了 N、P、K、S、Mn、Fe、Zn、Cu 和 Na 的含量，结果表明，基于植物的化学计量 N:P 比，赖草的生长主要受到 N 的限制。此外，路径分析表明，N 与 K、S、Cu 和 Zn 显著相关。因此，这四种元素的平衡可能受到限制。植被覆盖度为 100%-70%的样地中 Cu 的内稳指数（HCu）仅为 0.79，被归类为敏感元素。然而，K、S 和 Zn 与 N 的浓度显著相关，它们没有内稳特征。这些结果表明，在处理盐碱胁迫时，添加含有 K、S 和 Zn 的肥料以避免生长受限非常重要。Na+是与土壤高碱性相关的离子，即使在植被覆盖度仅为 40%-10%的样地中，它在赖草中的内稳性也较弱。当土壤 Na+超过 16000mg/kg 时，赖草的内稳机制似乎被破坏，导致 Na+的快速且可能有害的积累。适当控制 N 含量可以减轻 Na 胁迫对赖草的毒性，并增强其 Na 耐受性。总之，这些结果表明，应采用 N、K、S、Zn 和 Cu 的联合施肥来改善草地生长。本研究结果可为可持续草地管理提供参考依据。
