Effects of CO/sub 2/ enrichment and carbohydrate content on the dark respiration of soybeans
During the period of most active leaf expansion, the foliar dark respiration rate of soybeans (Glycine max cv Williams), grown for 2 weeks in 1000 microliters CO/sub 2/ per liter air, was 1.45 milligrams CO/sub 2/ evolved per hour leaf density thickness, and this was twice the rate displayed by leaves of control plants (350 microliters CO/sub 2/ per liter air). There was a higher foliar nonstructural carbohydrate level (e.g. sucrose and starch) in the CO/sub 2/ enriched compared with CO/sub 2/ normal plants. For example, leaves of enriched plants displayed levels of nonstructural carbohydrate equivalent to 174 milligrams glucose per gram dry weight compared to the 84 milligrams glucose per gram dry weight found in control plant leaves. As the leaves of CO/sub 2/ enriched plants approached full expansion, both the foliar respiration rate and carbohydrate content of the CO/sub 2/ enriched leaves decreased until they were equivalent with those same parameters in the leaves of control plants. A strong positive correlation between respiration rate and carbohydrate content was seen in high CO/sub 2/ adapted plants, but not in the control plants. Mitochondria, isolated simultaneously from the leaves of CO/sub 2/ enriched and control plants, showed no difference in NADH or malate-glutamate dependent O/sub 2/ uptake, and there were no observed differences in the specific activities of NAD/sup +/ linked isocitrate dehydrogenase and cytochrome c oxidase. Since the mitochondrial O/sub 2/ uptake and total enzyme activities were not greater in young enriched leaves, the increase in leaf respiration rate was not caused by metabolic adaptations in the leaf mitochondria as a response to long term CO/sub 2/ enrichment. It was concluded, that the higher respiration rate in the enriched plant's foliage was attributable, in part, to a higher carbohydrate status. 28 references, 4 figures, 3 tables.
- Research Organization:
- Dept. of Agriculture, Beltsville, MD
- OSTI ID:
- 6896870
- Journal Information:
- Plant Physiol.; (United States), Vol. 79
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
CARBON DIOXIDE
BIOLOGICAL EFFECTS
GLYCINE HISPIDA
RESPIRATION
OXIDOREDUCTASES
ENZYME ACTIVITY
CARBOHYDRATES
EXPERIMENTAL DATA
LEAVES
MITOCHONDRIA
NADH2
OXYGEN
PLANT GROWTH
BACTERIA
CARBON COMPOUNDS
CARBON OXIDES
CELL CONSTITUENTS
CHALCOGENIDES
COENZYMES
DATA
ELEMENTS
ENZYMES
GROWTH
INFORMATION
LEGUMINOSAE
MICROORGANISMS
NONMETALS
NUCLEOTIDES
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANOIDS
OXIDES
OXYGEN COMPOUNDS
PLANTS
RHIZOBIUM
560300* - Chemicals Metabolism & Toxicology
550200 - Biochemistry