Chronic exposure to low concentrations of ozone (O3) reduced growth and dry matter accumulation and increased leaf senescence in hybrid poplar Populus deltoides × trichocarpa. Plants were grown in controlled environment chambers and for 10 weeks were exposed daily for 5·5 h to 0·025, 0·050, 0·085 or 0·125 μl litre-1 O3. No treatment effects were observed during the first 6 weeks of exposure, except for accelerated leaf senescence in the highest O3 treatment. In contrast, during the final 4 weeks elevated O3 treatments resulted in reduced relative height and diameter growth rates as well as increased leaf senescence. By the end of the study O3 exposure had resulted in decreased plant height and diameter and number of leaves per plant, and in decreased leaf, stem, root and total dry mass per plant. Dry weights of plants in the 0·125 and 0·085 μl litre-1 treatments were 10-15% lower than in the 0·025 and 0·050 μl litre-1 treatments. Ozone treatments had no effect on partitioning of dry matter. The effects of O3 were linear with respect to treatment concentration.
|Original language||English (US)|
|Number of pages||13|
|Journal||Environmental Pollution. Series A, Ecological and Biological|
|State||Published - 1985|
Bibliographical noteFunding Information:
The research reported in this paper was sponsored in part by the Consortium for Environmental Forestry, Northeastern Forest Experiment Station, US Forest Service. The authors wish to thank Ms Yip-Fong Chia, Ms Becky Hon and Mr Charles Alexander for technical assistance and Drs R. G. Amundson and L. H. Weinstein for reviewing the manuscript.
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