Genetic variation in response to elevated CO 2 in three grassland perennials — a field experiment with two competition regimes

Abstract

Intraspecific variation in the response to increased concentrations of atmospheric CO 2 was investigated in three plant species ( Bromus erectus, Prunella vulgaris, P. grandiflora) in a calcareous grassland. Genotypes of each species were grown both in multispecies communities and under reduced competition pressure in tubes buried in the soil. Plant growth was reduced in the artificial communities but no significant effect of CO 2 was observed on any of the measured traits. Significant genotype-by-CO 2 interactions were found in two species when plants were grown under reduced competition in the tubes. No genotype-by-CO 2 interactions were found for the same genotypes grown in the multispecies communities indicating that genetic variation was swamped by large environmental variation. Furthermore, no correlations were observed between CO 2 responses of identical genotypes grown individually in tubes and in multispecies communities. This result cautions about the ability to predict CO 2-induced evolutionary changes from data of individually-grown plants.