Interspecific and intraspecific variability in the response of grasses and legumes to free air CO sub(2) enrichment

• Published in: Acta oecologica (Montrouge) 1997-01, Vol.18 (3), p.269-275
• Main Authors: Luescher, A, Noesberger, J
• Format: Article
• Language: English
• ISSN: 1146-609X

Nine to fourteen genotypes of seven grass and two legume species from permanent grassland were grown at two levels of atmospheric CO sub(2) concentration in gaps of established Lolium perenne swards in a Free Air Carbon dioxide Enrichment (FACE) experiment. Cumulative biomass of individual plants was determined for two growing seasons. In the first year, elevated CO sub(2) increased biomass production in all species. The CO sub(2)-induced increase in the biomass of Trifolium repens and T. pratense (159%) was much greater than the increase in the grass species (27%). In the second year the response to elevated CO sub(2) was weaker in grasses (2%, ns) and legumes (73%). However, interspecific differences in the response to CO sub(2) remained significant. Interspecific differences in the response to elevated CO sub(2) occurred between the two functional groups of grasses and legumes, while within these groups no significant interspecific differences were found. In contrast to the interspecific variability in the response to CO sub(2), no significant intraspecific variability in the response to CO sub(2) was detected. Our results suggest that significant interspecific differences in the response to CO sub(2) occur. Intraspecific differences in the response to elevated CO sub(2) were, however, not detected. Thus, it seems unlikely that evolutionary adaptation of the species' response to elevated CO sub(2) will level out the interspecific differences in the response to CO sub(2).