Fine Root Length of Maize Decreases in Response to Elevated CO2 Levels in Soil

To assess the environmental risks of carbon capture and storage (CCS) due to underground CO2 leakage, many studies have examined the impact on plant growth; however, the effect of leaked CO2 on root morphology remains poorly understood. This study simulated the effects of CO2 leakage from CCS on maize (Zea mays L.) root systems through pot experiments-one control treatment (no added CO2) and two elevated soil CO2 treatments (1000 gm(-2) d(-1) and 2000 gm(-2) d(-1)). Compared with the control, root length, root surface area, and root volume were reduced by 44.73%, 34.14%, and 19.16%, respectively, in response to CO2 treatments with a flux of 2000 g m(-2) d(-1). Meanwhile, the fine root length in CO2 treatments with a flux of 1000 g m(-2) d(-1) and 2000 g m(-2) d(-1) were reduced by 29.44% and 45.88%, respectively, whereas no obvious difference in regard to coarse roots was found. Understanding changes in plant root morphology in this experiment, especially the decrease in the fine root length, are essential for explaining plant responses to CO2 leakage from CCS.