College of Earth Sciences, Jilin University, Changchun 130061, China.
College of Earth Sciences, Jilin University, Changchun 130061, China.
Ecotoxicol Environ Saf. 2018 Dec 15;165:243-249. doi: 10.1016/j.ecoenv.2018.09.020. Epub 2018 Sep 7.
Soil salinization is a major cause of land degradation and hinders the effective utilization of agricultural land resources. Leymus chinensis (L. chinensis), as a dominant species with wide ecological amplitude, plays an important role in improving saline-alkali grasslands and indicating the degree of salinization. In this study, a sand culture experiment (nitrogen and phosphorus addition accompanied by saline-alkali stress) was designed to investigate the impact of different saline-alkali environments on the ecological stoichiometric homeostasis of L. chinensis with the aim of elucidating the saline-alkali resistance mechanisms. The results showed that the homeostasis indexes of N, P and N:P in the aboveground part of L. chinensis were generally higher than those in the belowground part under different saline-alkali conditions. Furthermore, the homeostasis index of N (H) was greater than that of P (H) in the aboveground part, whereas H was less than H in the belowground part. This indicates that the growth aboveground of L. chinensis was mainly dependent on N, whereas the growth belowground was mainly affected by P. The homeostasis index of the aboveground organs was 4.45-12.93 under pH 7-9.8. In contrast, H and H in the belowground organs did not conform to a homeostasis model when pH > 9.1. Consequently, when L. chinensis is subjected to high saline-alkali stress, the homeostasis reaction of the roots is more sensitive than that of the aboveground organs.
土壤盐渍化是土地退化的主要原因之一，阻碍了农业土地资源的有效利用。赖草（L. chinensis）作为一种生态幅度较宽的优势种，在改良盐碱草地和指示盐渍化程度方面发挥着重要作用。本研究通过沙培实验（氮磷添加伴随盐碱胁迫），探讨了不同盐碱环境对赖草生态化学计量内稳性的影响，旨在阐明其耐盐碱性机制。结果表明，在不同盐碱条件下，赖草地上部分的 N、P 和 N:P 内稳性指标普遍高于地下部分。此外，地上部分的 N 内稳性指数（H）大于 P 内稳性指数（H），而地下部分的 H 小于 H。这表明赖草地上部分的生长主要依赖于 N，而地下部分的生长主要受 P 影响。在 pH 7-9.8 范围内，地上器官的内稳性指数为 4.45-12.93。相比之下，当 pH >9.1 时，地下器官的 H 和 H 不符合内稳性模型。因此，当赖草受到高盐碱胁迫时，根系的内稳性反应比地上器官更敏感。
