Effects of doubled atmospheric CO 2 concentration on apple trees I. Growth analysis
Year: 2001
Type: article
Abstract: Summary Two year old apple ( Malus domestica Borkh. cv. 'Golden Delicious') trees on 'M9' were exposed to ambient (350 ± 10 ppm) and doubled (700 ± 10 ppm) atmospheric CO 2 for 120 d in growth chambers situated in an apple orchard. Doubled CO 2 promoted tree growth, indicated by more leaves and shoots, a larger average leaf area, and total leaf dry weight per tree, as well as a wider canopy and trunk diameter. Average shoot length and diameter, shoot length per tree, tree height, and total leaf area increased, whereas specific leaf area and leaf area ratio of the trees decreased at 700 ppm CO 2 . When compared to trees grown under 350 ppm CO 2 , 700 ppm CO 2 -treated trees stimulated the mean daily growth rate of total leaf area by 73-130%, total shoot length by 161-162%, and plant dry mass by 134-158%, respectively. Impacts of long-term atmospheric CO 2 enrichment on dry weight ratio in different components of the trees were more prominent in above-ground organs than in roots. High CO 2 raised leaf and shoot dry weight ratio, but reduced stem dry weight ratio, whereas root dry weight ratio and root/shoot ratio of the trees were not affected throughout the experiment. On average, net assimilation rate and relative growth rate were 0.6-1.7 g m -2 d -1 and 1.2-3.9 g kg -1 d -1 higher in trees grown at 700 than in those at 350 ppm CO 2 , but tended to decline with the duration of CO 2 treatment. The physiological and morphological mechanisms for the increased apple tree growth and plant development by the doubled atmospheric CO 2 concentration were associated with net assimilation rate and relative growth rate of the plants as well as cell differentiation and elongation of the plant organs. The adjustment of plant growth under long-term atmospheric CO 2 enrichment resulted from the plant adaptation to high CO 2 conditions, which was affected by carbon sink/source availability and strength.
Authors: K. Chen, G. Q. Hu, F. Lenz
Institutions: Oklahoma State University, University of Bonn
Language: English
Subfield: Plant Science
Domain: Life Sciences
SDGs: Zero hunger, Climate action
Open Access status: hybrid
OpenAlex ID: W4408868802