Biomass Production and Carbohydrate Content of <i>Arabidopsis thaliana</i> at Atmospheric CO₂ Concentrations from 390 to 1680 μl l^‐1

Abstract

Abstract: The concentration dependency of the impact of elevated atmospheric CO 2 concentrations on Arabidopsis thaliana L. was studied. Plants were exposed to nearly ambient (390), 560, 810, 1240 and 1680 μl I ‐1 CO 2 during the vegetative growth phase for 8 days. Shoot biomass production and dry matter content were increased upon exposure to elevated CO 2 . Maximal increase in shoot fresh and dry weight was obtained at 560 μl I ‐1 CU 2 , which was due to a transient stimulation of the relative growth rate for up to 3 days. The shoot starch content increased with increasing CO 2 concentrations up to two‐fold at 1680 μl I ‐1 CO 2 , whereas the contents of soluble sugars and phenolic compounds were hardly affected by elevated CO 2 . The chlorophyll and carotenoid contents were not substantially affected at elevated CO 2 and the chlorophyll a/b ratio remained unaltered. There was no acclimation of photosynthesis at elevated CO 2 ; the photosynthetic capacity of leaves, which had completely developed at elevated CO 2 was similar to that of leaves developed in ambient air. The possible consequences of an elevated atmospheric CO 2 concentration to Arabidopsis thaliana in its natural habitat is discussed.