PHOTOSYNTHETICA

Photosynthetica 2018, 56(3):921-931 | DOI: 10.1007/s11099-017-0711-6

Response of dominant grassland species in the temperate steppe of Inner Mongolia to different land uses at leaf and ecosystem levels

M. Liu¹, J. R. Gong^1,*, Y. Pan¹, Q. P. Luo¹, Z. W. Zhai¹, L. L. Yang¹, S. Xu¹

¹ State Key Laboratory of Surface Processes and Resource Ecology, College of Resources Science and Technology, Faculty of Geographical Science, Beijing Normal University, Beijing, China

In order to study the responses of dominant species to different land uses in the semiarid temperate grassland of Inner Mongolia, we tested the physiological responses of Stipa grandis, Leymus chinensis, and Artemisia frigida to mowing, grazing exclusion, and grazing land uses at the leaf and ecosystem levels. The grazing-exclusion and mowing sites released CO₂, but the grazing site was a net carbon sink. L. chinensis and S. grandis contributed more to the ecosystem CO₂ exchange than A. frigida. At the grazing-exclusion and mowing sites, Leymus chinensis and Stipa grandis both exhibited a higher light-saturation point and higher maximum photosynthetic rate than that at the grazing site, which increased photosynthesis and growth compared to those at the grazing site. In contrast, A. frigida possessed a higher nitrogen content than the other species, and more of the light energy used for photosynthesis, particularly at the grazing site.

Additional key words: gas exchange; osmoregulation; water-use efficiency

Received: June 9, 2016; Accepted: February 10, 2017; Prepublished online: September 1, 2018; Published: August 1, 2018  Show citation