The effect of light on ABA catabolism in excised seedlings of Phaseolus vulgaris L. cv. top-crop

Conference · Tue May 01 04:00:00 EDT 1990 · Plant Physiology, Supplement; (USA)

OSTI ID:5769998

Cowan, A K; Myemane, D M ^[1]

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1. Rhodes Univ., Grahamstown (South Africa)

Studies on the influence of light quality on ABA catabolism have implicated the involvement of phytochrome in this process. Detailed experiments were therefore carried out to determine whether light could be a factor involved in the regulation of ABA catabolism in higher plants. Excised, etiolated seedlings of Phaseolus vulgaris (4.5g fr. wt.) were supplied with (R,S,)-(2-{sup 14}C)-ABA (5.0 kBq) and exposed to various combinations of red (37 {mu}mol m{sup {minus}2} s{sup {minus}1}) and far-red (23 {mu}mol m{sup {minus}2} s{sup {minus}1}) light. Following light treatments seedlings were returned to darkness for the remainder of the 20 h incubation period. Far-red light illumination stimulated ABA catabolism whereas red light had no significant effect on this process. Kinetic studies and analysis of water-soluble conjugates revealed that far-red light treatment enhanced the sequestration of ABA and its acidic products. The apparent inhibition of ABA catabolism by red light was relieved, if red light irradiation was followed immediately by a dose of far-red light. Thus, these data indicate that ABA catabolism might be mediated by phytochrome and that control is exerted at the level of conjugation rather than oxidation.

• OSTI ID: 5769998
• Report Number(s): CONF-9007196--
• Conference Information: Journal Name: Plant Physiology, Supplement; (USA) Journal Volume: 93:1
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540110
550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ABSCISIC ACID
AUXINS
BIOLOGICAL EFFECTS
CARBON 14 COMPOUNDS
CARBOXYLIC ACIDS
ELECTROMAGNETIC RADIATION
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
LEGUMINOSAE
MAGNOLIOPHYTA
MAGNOLIOPSIDA
MONOCARBOXYLIC ACIDS
ORGANIC ACIDS
ORGANIC COMPOUNDS
PHASEOLUS
PLANT GROWTH REGULATORS
PLANTS
RADIATIONS
TRACER TECHNIQUES
VISIBLE RADIATION