|| 要旨トップ | 目次 |||日本生態学会第59回全国大会 (2012年3月，大津) 講演要旨
一般講演（ポスター発表） P3-023A (Poster presentation)
The atmospheric CO2 concentration is now increasing and will reach 700 ppm at the end of this century. Relative growth rate (RGR), an important component of fit ness, is an integration of various physiological and morphological traits. Here we questioned (1) whether within-species variation exsits in CO2 response of RGR and, if so, (2) what physiological or morphological traits are responsible for the variation. We thus studied among-genotype variation in RGR at two CO2 concentrations in Arabidopsis thaliana. There was a considerable variation in RGR among genotypes, which was explained mainly by a physiological trait, net assimilation rate (NAR), rather than by morphological traits such as leaf area ratio. The genotypes with higher RGR at the high CO2 tended to have a greater response to CO2 enrichment, while RGR at ambient condition was less related to the RGR response. We determined carbon uptake (photosynthesis) and loss (respiration) rates of the genotypes. NAR was positively correlated with the carbon balance and was explained mainly by photosynthesis. Carbon loss at the high CO2 concentration was negatively correlated with carbon balance, which suggests that lower respiration rate also partly contributed to increasing carbon gain of the plants.