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Physiological responses of birch (Betula pendula) to ozone: a comparison between open-soil-grown trees exposed for six growing seasons and potted seedlings exposed for one season.
Tree Physiol 2003; 23(9):603-14TP

Abstract

Physiological responses of 4-year-old potted saplings of an O3-tolerant clone of Betula pendula Roth to short-term ozone (O3) exposure (one growing season) were compared with those of 6-year-old open-soil-grown trees of the same clone fumigated with O3 for six growing seasons. In the 2001 growing season, both groups of plants were exposed to ambient (control) and 1.6x ambient (elevated) O3 concentration under similar microclimatic conditions in a free air O3 exposure facility. Growth, net photosynthesis, stomatal conductance, stomatal density, visible foliar injury, starch and nutrient concentrations, bud formation and differences in O3 responses between lower, middle and upper sections of the canopy were determined. The potted saplings were unaffected by elevated O3 concentration, whereas the open-soil-grown trees showed a 3-38% reduction in shoot growth, a 22% reduction in number of overwintering buds, a 26-65% decrease in autumnal net photosynthesis, 30% and 20-23% reductions in starch and nitrogen concentrations of senescing leaves, respectively, and disturbances in stomatal conductance. The greater O3 sensitivity of open-soil-grown trees compared with potted saplings was a result of senescence-related physiological factors. First, a lower net photosynthesis to stomatal conductance ratio in open-soil-grown trees at the end of the season promoted O3 uptake and decreased photosynthetic gain, leading to the onset of visible foliar injuries. Second, decreased carbohydrate reserves may have resulted in deleterious carry-over effects arising from the reduced formation of over-wintering buds. Finally, the leaf-level O3 load was higher for open-soil-grown trees than for potted saplings because of slower leaf senescence in the trees. Thus, O3 sensitivity in European white birch increases with increasing exposure time and tree size.

Authors+Show Affiliations

Department of Ecology and Environmental Science, University of Kuopio, POB 1627, 70211 Kuopio, Finland. Elina.Oksanen@uku.fi

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

12750053

Citation

Oksanen, Elina. "Physiological Responses of Birch (Betula Pendula) to Ozone: a Comparison Between Open-soil-grown Trees Exposed for Six Growing Seasons and Potted Seedlings Exposed for One Season." Tree Physiology, vol. 23, no. 9, 2003, pp. 603-14.
Oksanen E. Physiological responses of birch (Betula pendula) to ozone: a comparison between open-soil-grown trees exposed for six growing seasons and potted seedlings exposed for one season. Tree Physiol. 2003;23(9):603-14.
Oksanen, E. (2003). Physiological responses of birch (Betula pendula) to ozone: a comparison between open-soil-grown trees exposed for six growing seasons and potted seedlings exposed for one season. Tree Physiology, 23(9), pp. 603-14.
Oksanen E. Physiological Responses of Birch (Betula Pendula) to Ozone: a Comparison Between Open-soil-grown Trees Exposed for Six Growing Seasons and Potted Seedlings Exposed for One Season. Tree Physiol. 2003;23(9):603-14. PubMed PMID: 12750053.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Physiological responses of birch (Betula pendula) to ozone: a comparison between open-soil-grown trees exposed for six growing seasons and potted seedlings exposed for one season. A1 - Oksanen,Elina, PY - 2003/5/17/pubmed PY - 2004/12/16/medline PY - 2003/5/17/entrez SP - 603 EP - 14 JF - Tree physiology JO - Tree Physiol. VL - 23 IS - 9 N2 - Physiological responses of 4-year-old potted saplings of an O3-tolerant clone of Betula pendula Roth to short-term ozone (O3) exposure (one growing season) were compared with those of 6-year-old open-soil-grown trees of the same clone fumigated with O3 for six growing seasons. In the 2001 growing season, both groups of plants were exposed to ambient (control) and 1.6x ambient (elevated) O3 concentration under similar microclimatic conditions in a free air O3 exposure facility. Growth, net photosynthesis, stomatal conductance, stomatal density, visible foliar injury, starch and nutrient concentrations, bud formation and differences in O3 responses between lower, middle and upper sections of the canopy were determined. The potted saplings were unaffected by elevated O3 concentration, whereas the open-soil-grown trees showed a 3-38% reduction in shoot growth, a 22% reduction in number of overwintering buds, a 26-65% decrease in autumnal net photosynthesis, 30% and 20-23% reductions in starch and nitrogen concentrations of senescing leaves, respectively, and disturbances in stomatal conductance. The greater O3 sensitivity of open-soil-grown trees compared with potted saplings was a result of senescence-related physiological factors. First, a lower net photosynthesis to stomatal conductance ratio in open-soil-grown trees at the end of the season promoted O3 uptake and decreased photosynthetic gain, leading to the onset of visible foliar injuries. Second, decreased carbohydrate reserves may have resulted in deleterious carry-over effects arising from the reduced formation of over-wintering buds. Finally, the leaf-level O3 load was higher for open-soil-grown trees than for potted saplings because of slower leaf senescence in the trees. Thus, O3 sensitivity in European white birch increases with increasing exposure time and tree size. SN - 0829-318X UR - https://www.unboundmedicine.com/medline/citation/12750053/Physiological_responses_of_birch__Betula_pendula__to_ozone:_a_comparison_between_open_soil_grown_trees_exposed_for_six_growing_seasons_and_potted_seedlings_exposed_for_one_season_ L2 - https://academic.oup.com/treephys/article-lookup/doi/10.1093/treephys/23.9.603 DB - PRIME DP - Unbound Medicine ER -