/sup 14/CO/sub 2/ pulse-/sup 12/CO/sub 2/ chase analyses of C/sub 4/-acid metabolism in C/sub 3/-C/sub 4/ intermediate species of Flaveria at the CO/sub 2/ compensation concentration (r). [Flaveria floridana; Flaveria anomala]
Photosynthetic C/sub 4/-acid metabolism in leaves of C/sub 3/-C/sub 4/ intermediate Flaveria species was examined by /sup 14/CO/sub 2/ pulse-/sup 12/CO/sub 2/ chase experiments conducted at external CO/sub 2/-levels approximating air and ..gamma... Analysis of the percent distribution of /sup 14/C after a 10-s pulse showed an enhanced labeling of malate and aspartate at ..gamma.. in the C/sub 3/-C/sub 4/ species. This stimulation of /sup 14/CO/sub 2/ fixation by PEP carboxylase ranged from 1.7-(F. floridana) to 3.6-fold (F. anomala). A /sup 12/CO/sub 2/-chase at ..gamma.. revealed a significant turnover of C/sub 4/ acids for only F. floridana. C/sub 4/-acid labeling in C/sub 3/ and C/sub 4/ Flaveria species was relatively unresponsive to changes in pCO/sub 2/. These data imply that the C/sub 3/-C/sub 4/ intermediate Flaveria species with less advanced C/sub 4/ attributes have a greater capacity for increased CO/sub 2/ fixation via PEP carboxylase at ..gamma.. versus air. Thus, labeling of C/sub 3/-C/sub 4/ leaves at ..sigma.. may be an effective tool for assessing the degree of true C/sub 4/-photosynthesis as well as the potential mechanism involved in reducing photorespiration.
- Research Organization:
- Univ. of Nebraska, Lincoln
- OSTI ID:
- 6028154
- Report Number(s):
- CONF-8707108-; TRN: 87-037214
- Journal Information:
- Plant Physiol., Suppl.; (United States), Vol. 83:4; Conference: Annual meeting of the American Society of Plant Physiologists, St. Louis, MO, USA, 19 Jul 1987
- Country of Publication:
- United States
- Language:
- English
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Capacity for C/sub 4/ photosynthesis among relatively advanced species of Flaveria. [Flaveria vaginata; Flaveria palmeri; Flaveria australasica; Flaveria bidentis; Flaveria trinervia]
Photosynthetic characteristics of reciprocal backcrosses between F/sub 1/ hybrid (C/sub 3/-C/sub 4/ x C/sub 4/) and C/sub 4/ Flaveria species. [Flaveria floridana; Flaveria brownii]
Related Subjects
C4 SPECIES
PHOTOSYNTHESIS
CARBOXYLIC ACIDS
METABOLISM
ASPARTIC ACID
CARBON 14 COMPOUNDS
CARBON DIOXIDE
CARBON DIOXIDE FIXATION
LEAVES
MALIC ACID
RESPIRATION
TRACER TECHNIQUES
AMINO ACIDS
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
CHEMICAL REACTIONS
HYDROXY ACIDS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
ORGANIC ACIDS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
SYNTHESIS
550201* - Biochemistry- Tracer Techniques