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Title: Growth and physiology of woody plants in response to elevated CO{sub 2} and defoliation in an open-top field study

Seedlings of sugar maple (Acer saccharum) and trembling aspen (Populus tremuloides) were exposed for an entire growing season to ambient (-357 {mu}mol mol{sup -1}) or elevated ({approximately}650 {mu}mol mol{sup -1}) levels of CO{sub 2}. To simulate natural defoliation, a subset of the seedlings within each CO{sub 2} treatment also had 50 % of their foliage clipped in late June. During the growing season there were three sequential harvests. The first was coincident with defoliation, followed by a mid-season harvest in early August and a final harvest after leaf senescence. Allocational, morphological and physiological determinants of growth were measured at each harvest. This is the first of two years of CO{sub 2} exposure, and preliminary analyses indicate an increase in both photosynthesis and growth for trembling aspen and sugar maple. However, after accounting for initial growth differences, the magnitude of this enhancement appears to have diminished over the course of the growing season, which can largely be explained by changes in physiological response. Interestingly, there was no growth {open_quotes}acclimation{close_quotes} to an enriched-CO{sub 2} environment for sugar maple seedlings that had been artificially defoliated.
Authors:
; ;  [1]
  1. Univ. of Wisconsin, Madison, WI (United States)
Publication Date:
OSTI Identifier:
95901
Report Number(s):
CONF-9507129-
Journal ID: BECLAG; ISSN 0012-9623; TRN: 95:004728-0169
Resource Type:
Journal Article
Resource Relation:
Journal Name: Bulletin of the Ecological Society of America; Journal Volume: 76; Journal Issue: 2; Conference: 80. anniversary of the transdisciplinary nature of ecology, Snowbird, UT (United States), 30 Jul - 3 Aug 1995; Other Information: PBD: Jun 1995
Country of Publication:
United States
Language:
English
Subject:
56 BIOLOGY AND MEDICINE, APPLIED STUDIES; CARBON DIOXIDE; ECOLOGICAL CONCENTRATION; BIOLOGICAL EFFECTS; TREES; PLANT GROWTH; PHOTOSYNTHESIS; MAPLES; ASPENS