Journal Article

Carbon partitioning and allocation in northern red oak seedlings and mature trees in response to ozone

L. J. Samuelson and J. M. Kelly

in Tree Physiology

Volume 16, issue 10, pages 853-858
Published in print October 1996 | ISSN: 0829-318X
e-ISSN: 1758-4469 | DOI: http://dx.doi.org/10.1093/treephys/16.10.853
Carbon partitioning and allocation in northern red oak seedlings and mature trees in response to ozone

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Northern red oak (Quercus rubra L.) seedlings and trees differ in their response to ozone. Previous work reported reductions in net photosynthesis, carboxylation efficiency and quantum yield of mature tree leaves, whereas seedling processes were unaffected by the same ozone exposure. To further characterize differences in ozone response between seedlings and mature trees, we examined carbon partitioning and allocation in 32-year-old trees and 4-year-old seedlings of northern red oak after exposure to subambient (seasonal SUM00 dose (sum of all hourly ozone exposures) = 31 ppm-h), ambient (SUM00 dose = 85 ppm-h) and twice ambient (SUM00 dose = 151 ppm-h) ozone concentrations for three growing seasons. For mature trees, ozone exposure decreased foliar starch partitioning, increased starch partitioning in branches and increased 14C retention in leaves. In contrast, starch partitioning in leaves and branches, and foliar 14C retention in seedlings were unaffected by ozone exposure, but soluble carbohydrate concentrations in coarse and fine roots of seedlings were reduced. Differences in carbohydrate demand between seedlings and mature trees may underlie the higher leaf ozone uptake rates and greater physiological response to ozone in mature northern red oak trees compared with seedlings.

Keywords: Quercus rubra; carbon metabolism; scaling

Journal Article.  0 words. 

Subjects: Plant Sciences and Forestry

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