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

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.
Authors:
;  [1]
  1. (Rhodes Univ., Grahamstown (South Africa))
Publication Date:
OSTI Identifier:
5769998
Report Number(s):
CONF-9007196--
Journal ID: ISSN 0079-2241; CODEN: PPYSA
Resource Type:
Conference
Resource Relation:
Journal Name: Plant Physiology, Supplement; (USA); Journal Volume: 93:1; Conference: Annual meeting of the American Society of Plant Physiologists, Indianapolis, IN (USA), 29 Jul - 2 Aug 1990
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; 54 ENVIRONMENTAL SCIENCES; ABSCISIC ACID; PHASEOLUS; VISIBLE RADIATION; BIOLOGICAL EFFECTS; CARBON 14 COMPOUNDS; TRACER TECHNIQUES; AUXINS; CARBOXYLIC ACIDS; ELECTROMAGNETIC RADIATION; ISOTOPE APPLICATIONS; LABELLED COMPOUNDS; LEGUMINOSAE; MAGNOLIOPHYTA; MAGNOLIOPSIDA; MONOCARBOXYLIC ACIDS; ORGANIC ACIDS; ORGANIC COMPOUNDS; PLANT GROWTH REGULATORS; PLANTS; RADIATIONS 550201* -- Biochemistry-- Tracer Techniques; 540110