Direct and indirect effects of atmospheric carbon dioxide enrichment on leaf respiration of glycine max (L.) Merr
- Duke Univ., Durham, NC (United States)
Long-term and short-term effects of CO{sub 2} enrichment on dark respiration were investigated using soybean (Glycine max [L.] Merr.) plants grown at either 35.5 or 71.0 Pa CO{sub 2}. Indirect effects, or effects of growth in elevated CO{sub 2}, were examined using a functional model that partitioned respiration into growth and maintenance components. Direct effects, or immediate effects of a short-term change in CO{sub 2}, were examined by measuring dark respiration, first, at the CO{sub 2} partial pressure at which plants were grown, and second, after equilibration in the reciprocal CO{sub 2} partial pressure. The functional component model indicated that the maintenance coefficient of respiration increased 34% with elevated CO{sub 2}, whereas the growth coefficient was not significantly affected. Changes in maintenance respiration were correlated with a 33% increase in leaf total nonstructural carbohydrate concentration, but leaf nitrogen content of soybean leaves was not affected by CO{sub 2} enrichment. Thus, increased maintenance respiration may be a consequence of increased nonstructural carbohydrate accumulation. When whole soybean plants were switched from low CO{sub 2} to high CO{sub 2} for a brief period, leaf respiration was always reduced. However, this direct effect of CO{sub 2} partial pressure was approximately 50% less in plants grown in elevated CO{sub 2}. We conclude from this study that there are potentially important effects of CO{sub 2} enrichment on plant respiration but the the effects are different for plants given a short-term increase in CO{sub 2} partial pressure versus plants grown in elevated CO{sub 2}. 30 refs., 3 figs., 3 tabs.
- OSTI ID:
- 426051
- Journal Information:
- Plant Physiology (Bethesda), Journal Name: Plant Physiology (Bethesda) Journal Issue: 2 Vol. 104; ISSN 0032-0889; ISSN PLPHAY
- Country of Publication:
- United States
- Language:
- English
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