The optimal CO2 concentrations for the growth of three perennial grass species

作者：Yunpu Zheng, Fei Li, Lihua Hao, Arshad Ali Shedayi, Lili Guo, Chao Ma, Bingru Huang, Ming Xu · 发表于：BMC Plant Biology · 年份：2018 · DOI：10.1186/s12870-018-1243-3 · 被引用次数：63 · 研究领域：Plant responses to elevated CO2、Atmospheric chemistry and aerosols、Plant Water Relations and Carbon Dynamics

Grasslands are one of the most representative vegetation types accounting for about 20% of the global land area and thus the response of grasslands to climate change plays a pivotal role in terrestrial carbon balance. However, many current climate change models, based on earlier results of the doubling-CO 2 experiments, may overestimate the CO 2 fertilization effect, and as a result underestimate the potentially effects of future climate change on global grasslands when the atmospheric CO 2 concentration goes beyond the optimal level. Here, we examined the optimal atmospheric CO 2 concentration effect on CO 2 fertilization and further on the growth of three perennial grasses in growth chambers with the CO 2 concentration at 400, 600, 800, 1000, and 1200 ppm, respectively. All three perennial grasses featured an apparent optimal CO 2 concentration for growth. Initial increases in atmospheric CO 2 concentration substantially enhanced the plant biomass of the three perennial grasses through the CO 2 fertilization effect, but this CO 2 fertilization effect was dramatically compromised with further rising atmospheric CO 2 concentration beyond the optimum. The optimal CO 2 concentration for the growth of tall fescue was lower than those of perennial ryegrass and Kentucky bluegrass, and thus the CO 2 fertilization effect on tall fescue disappeared earlier than the other two species. By contrast, the weaker CO 2 fertilization effect on the growth of perennial ryegrass and Kentucky bl...