What was done
Pea (Pisum sativum) seeds were germinated and exposed to various atmospheric gas combinations in controlled environments to determine if elevated CO2 impacts root border cells, which are major contributors of root exudates in this and most other agronomic species.

What was learned
Elevated CO2 concentrations increased border-cell production in roots of pea seedlings. In fact, in going from ambient air to air enriched to 3,000 and 6,000 ppm CO2, border-cell numbers increased by over 50 and 100%, respectively.

What it means
As the CO2 content of the air increases, pea seedlings will likely produce greater numbers of root border cells, which should enhance the amount of root exudations occurring in their rhizospheres.  Thus, it is likely that associated soil fungal and microbial activities will be increased as a result of increases in plant-derived carbon inputs, which these organisms require to meet their energy needs; and this phenomenon should make the soil environment even more favorable for plant growth.