1. We tested the hypothesis that the net partitioning of dry mass and dry m
ass:area relationships is unaltered when plants are grown at elevated atmos
pheric CO2 concentrations.
2. The total dry mass of Dactylis glomerata, Bellis perennis and Trifolium
repens was higher for plants in 700 compared to 350 mu mol CO2 mol(-1) when
grown hydroponically in controlled-environment cabinets.
3. Shoot:root ratios were higher and leaf area ratios and specific leaf are
as lower in all species grown at elevated CO2. Leaf mass ratio was higher i
n plants of B. perennis and D. glomerata grown at elevated CO2.
4. Whilst these data suggest that CO2 alters the net partitioning of dry ma
ss and dry mass:leaf area relationships, allometric comparisons of the comp
onents of dry mass and leaf area suggest at most a small effect of CO2. CO2
changed only two of a total of 12 allometric coefficients we calculated fo
r the three species: v relating shoot to root dry mass was higher in D. glo
merata, whilst v relating leaf area to total dry mass was lower in T. repen
5. CO2 alone has very little effect on partitioning when the size of the pl
ant is taken into account.