Plant–plant interactions could mediate vegetation responses to rising atmospheric CO2 concentration ([CO2]), because some plants benefit more from [CO2] elevation than others. Van Loon et al. investigated how changes in performance due to elevated [CO2] are modified by aboveground plant–plant interactions.
They grew Plantago asiatica seeds originating from natural [CO2] springs and from ambient [CO2] in mono-stands of both origins as well as mixtures of both origins in climate rooms under different [CO2] levels. Their results showed that plant performance to elevated [CO2] was mainly determined by plastic responses and not by genotypic responses. However, this pattern was highly modified by plant–plant interactions.