Leaf level gas exchange and carbohydrate metabolism at elevated CO[sub 2]: Is a consensus emerging
- Ohio State Univ., Columbus, OH (United States)
Many predictions concerning whole plant, population, and ecosystem level responses to rising atmospheric CO[sub 2] are predicted on functional changes occurring at the leaf level. Net CO[sub 2] assimilation (P[sub n]), dark respiration, stomatal conductance, and nonstructural carbohydrate content (TNC) have been among the most intensively studied responses in long-term exposures of trees to elevated CO[sub 2]. A central theme in these studies has been the degree to which downregulation of photosynthesis occurs, and the role of nutrient availability in this response. At moderate to high leaf N, both conifer and hardwood species show sustained increases in P[sub n] over months to years, together with substantional increases in TNC. Low leaf N, however, significantly reduces P[sub n] stimulation by high CO[sub 2]. Effects on respiration are more variable, and may be tied to changes in leaf mass, growth rate, or N content. Important areas of uncertainty are in the interaction between leaf and canopy level responses and the regulation of the P[sub n] response by other environmental variables, particularly light intensity.
- OSTI ID:
- 7016184
- Report Number(s):
- CONF-940894-; CODEN: BECLAG
- Journal Information:
- Bulletin of the Ecological Society of America; (United States), Vol. 75:2; Conference: Annual Ecological Society of America (ESA) meeting: science and public policy, Knoxville, TN (United States), 7-11 Aug 1994; ISSN 0012-9623
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CARBON DIOXIDE
BIOLOGICAL EFFECTS
ECOLOGICAL CONCENTRATION
LEAVES
NUTRIENTS
PHOTOSYNTHESIS
BIOLOGICAL AVAILABILITY
NITROGEN
PHOSPHORUS
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
CHEMICAL REACTIONS
ELEMENTS
NONMETALS
OXIDES
OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
SYNTHESIS
560300* - Chemicals Metabolism & Toxicology