Background
The authors say it has been found that "elevated CO2 may promote the growth of some invasive species compared to native species," but they note that "the generality of this prediction and the mechanisms with which nonnative plants outperform natives is mostly unknown." Hence, they write that "it is important to study how physiological differences among native and invasive species interact with predicted changes in atmospheric composition."

What was done
Lei et al. grew well-watered individual seedlings of invasive Eupatorium adenophorum, its native conspecific, and a native congener (E. japonicum) in 5-liter pots filled with 4 kg of homogenized forest topsoil placed within closed-top chambers out-of-doors in southwest China at the Ailaoshan Station for Subtropical Forest Ecosystem Studies (24°32'N, 101°01'E) for a period of three months under ambient and double-ambient atmospheric CO2 concentrations, while measuring various plant properties and physiological processes both during and at the end of the experiment.

What was learned
The six scientists report that "CO2 enrichment increased relative growth rate by 8, 14, and 11% in invasive E. adenophorum, its native conspecific, and native E. japonicum, respectively; and they state that "the interactions between plant material and CO2 treatment were not significant for relative growth rate and biomass," while additionally indicating that "all studied materials responded similarly to CO2 enrichment."

What it means
Simply stated, in the words of Lei et al., "the results suggest that CO2 enrichment might not aggravate E. adenophorum invasion in the future."