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.
Marloes P. van Loon, Max Rietkerk, Stefan C. Dekker, Kouki Hikosaka, Miki U. Ueda, Niels P. R. Anten, 2016, 'Plant–plant interactions mediate the plastic and genotypic response of Plantago asiatica to CO2: an experiment with plant populations from naturally high CO2 areas', Annals of Botany, vol. 117, no. 7, pp. 1197-1207 http://dx.doi.org/10.1093/aob/mcw064