Xanthophylls and abscisic acid biosynthesis in water-stressed bean leaves
Experiments were designed to obtain evidence about the possible role of xanthophylls as abscisic acid (ABA) precursors in water-stressed leaves of Phaseolus vularis L. Leaves were exposed to /sup 14/CO/sub 2/ and the specific activities of several major leaf xanthophylls and stress-induced ABA were determined after a chase in /sup 12/CO/sub 2/ for varying periods of time. The ABA specific radioactivities were about 30 to 70% of that of lutein and violaxanthin regardless of the chase period. The specific activity of neoxanthin, however, was only about 15% of that of ABA. The effects of fluridone on xanthophyll and ABA levels and the extent of labeling of both from /sup 14/CO/sub 2/ were determined. Fluridone did not inhibit the accumulation of ABA when leaves were stressed once, although subsequent stresses in the presence of fluridone did lead to a reduced ABA accumulation. The incorporation of /sup 14/C from /sup 14/CO/sub 2/ into ABA and the xanthophylls was inhibited by fluridone and to about the same extent. The incorporation of /sup 18/O into ABA from violaxanthin which had been labeled in situ by means of the violaxanthin cycle was measured. The results indicated that a portion of the ABA accumulated during stress was formed from violaxanthin which had been labeled with /sup 18/O. The results of these experiments are consistent with a preformed xanthophyll(s) as the major ABA precursor in water-stressed bean leaves.
- Research Organization:
- State Univ. of New York, Syracuse
- OSTI ID:
- 5640424
- Journal Information:
- Plant Physiol.; (United States), Vol. 85:4
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ABSCISIC ACID
BIOSYNTHESIS
PHASEOLUS
BIOLOGICAL STRESS
PIGMENTS
CARBON 14 COMPOUNDS
CARBON DIOXIDE
LEAVES
OXYGEN 18
PRECURSOR
RESPONSE MODIFYING FACTORS
TRACER TECHNIQUES
WATER
AUXINS
BACTERIA
CARBON COMPOUNDS
CARBON OXIDES
CARBOXYLIC ACIDS
CHALCOGENIDES
EVEN-EVEN NUCLEI
HYDROGEN COMPOUNDS
ISOTOPE APPLICATIONS
ISOTOPES
LABELLED COMPOUNDS
LEGUMINOSAE
LIGHT NUCLEI
MICROORGANISMS
MONOCARBOXYLIC ACIDS
NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
OXYGEN ISOTOPES
PLANT GROWTH REGULATORS
PLANTS
RHIZOBIUM
STABLE ISOTOPES
SYNTHESIS
550201* - Biochemistry- Tracer Techniques