CO2 is a key constituent of the plant growth-promoting volatiles generated by bacteria in a sealed system.
Chunlei ZhangMengyue ZhangZhenwei YanFengxia WangXianzheng YuanShan ZhaoLei ZhangHuiyu TianZhaojun DingPublished in: Plant cell reports (2020)
The benefit of co-culturing was largely due to the CO2 generated by respiration of the bacteria.