Growth and crown architecture of two aspen genotypes exposed to interacting ozone and carbon dioxide

• Published in: Environmental pollution (1987) Vol. 115; no. 3; pp. 319 - 334
• Main Authors: Dickson, Richard E., Coleman, M.D., Pechter, Priit, Karnosky, David
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Oxford Elsevier Ltd 01.01.2001; Elsevier
• Subjects: Air Pollutants - adverse effects; Air Pollutants - pharmacology; Animal, plant and microbial ecology; Applied ecology; Atmosphere Exposure Chambers; Biological and medical sciences; Carbon - metabolism; Carbon Dioxide - pharmacology; Cloning, Organism; Crown architecture; Drug Interactions; Ecotoxicology, biological effects of pollution; Effects of pollution and side effects of pesticides on plants and fungi; Elevated CO 2; Forestry; Fundamental and applied biological sciences. Psychology; General forest ecology; Generalities. Production, biomass. Quality of wood and forest products. General forest ecology; Genotype; Genotypic response; Ozone - adverse effects; Ozone - pharmacology; Ozone exposure; Plant Structures - drug effects; Plant Structures - genetics; Plant Structures - growth & development; Populus tremuloides; Salicaceae - drug effects; Salicaceae - genetics; Salicaceae - growth & development; Trees - drug effects; Trees - genetics; Trees - growth & development; Populus tremuloides; Genotypic response; Ozone exposure; Crown architecture; Elevated CO 2; Open top chamber; Growth; Carbon dioxide; Ozone; Growth habit; Salicaceae; Pollutant; Medium enrichment; Plant architecture; Dicotyledones; Angiospermae; Air pollution; Hardwood forest tree; Spermatophyta; Climate modification
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/S0269-7491(01)00225-1

Ozone decreased wood strength caused terminals and long shoots to droop and increased the branch angle of termination. To study the impact of ozone (O 3) and O 3 plus CO 2 on aspen growth, we planted two trembling aspen clones, differing in sensitivity to O 3, in the ground in open-top chambers and exposed them to different concentrations of O 3 and O 3 plus CO 2 for 98 days. Ozone exposure (58 to 97 μl1 −1-h, total exposure) decreased growth and modified crown architecture of both aspen clones. Ozone exposure decreased leaf, stem, branch, and root dry weight particularly in the O 3 sensitive clone (clone 259). The addition of CO 2 (150 μl1 −1 over ambient) to the O 3 exposure counteracted the negative impact of O 3 only in the O 3 tolerant clone (clone 216). Ozone had relatively little effect on allometric ratios such as, shoot/ root ratio, leaf weight ratio, or root weight ratio. In both clones, however, O 3 decreased the shoot dry weight/shoot length ratio and shoot diameter. This decrease in wood strength caused both current terminals and long shoots to droop and increased the branch angle of termination. These results show that aspen growth is highly sensitive to O 3 and that O 3 can also significantly affect crown architecture. Aspen plants with drooping terminals and lateral branches would be at a competitive disadvantage in dense stands with limited light.