Homeostatic responses and growth of Leymus chinensis under incrementally increasing saline-alkali stress

PeerJ

article

Shujie Li¹  Yujin Huang¹  Yuefen Li¹ 

[1] College of Earth Sciences, Jilin University;Key laboratory of Mineral Resources Evaluation in Northeast Asia, Ministry of Land and Resources;Institute of Geographic Sciences and Natural Resources Research

关键词: Saline-alkali stress;    Stoichiometric homeostasis;    Ecological stoichiometry;    Specific growth rate;    L. chinensis;    Nitrogen and phosphorus;   

DOI  :  10.7717/peerj.10768

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

Despite considerable tolerance to salt and alkali stress, Leymus chinensis populations on the southwestern Songnen Plain in northern China are threatened by increasing soil salinity and alkalinity. To explore the species’ responses to saline-alkali stress, we grew it in substrates with varying concentrations of nitrogen (N) and phosphorus (P) while applying varying levels of saline-alkali stress (increasing in 14-, 17- or 23 -day intervals). We measured the plants’ contents of N and P, and the N:P ratio, and calculated their homeostasis indices (HN, HP and HN:P) under each nutrient and saline-alkali stress treatment. The N content was found to be more sensitive to saline-alkali stress than the P content. The N and P contents were highest and the N:P ratio was stable at pH 8.4. At both pH 8.1 and 8.4, HN:P HN HP, but the indices and their relations differed at other pH values. Exposure to saline-alkali stress for the 14-day incremental interval had weaker effects on the plants. Rapid changes in salinity-alkalinity weakened both the positive effects of the weakly alkaline conditions (pH 7.5–8.4) and the negative effects of more strongly alkaline conditions (pH 8.7 or 9.3) on L. chinensis. When L. chinensis plants lack N, applying N fertilizer will be extremely efficient. The optimal concentrations of N and P appeared to be 16 and 1.2 mmol/L, respectively. When the L. chinensis plants were N- and P-limited, the specific growth rate correlated positively with N:P, when limited by N it correlated positively with the environmental N concentration, and when limited by P it was weakly positively correlated with the environmental P concentration.

【 授权许可】

CC BY