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Influence of red irradiation and of removal of integuments on the metabolism of (±) [2‐ 14 C]‐abscisic acid by Lactuca sativa Grand Rapids achenes
Author(s) -
Orlandini M.,
Barthe Ph.,
Bulard C.
Publication year - 1988
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1988.tb09200.x
Subject(s) - abscisic acid , lactuca , chemistry , metabolism , aqueous solution , hydrolysis , imbibition , chromatography , biochemistry , nuclear chemistry , biology , germination , botany , organic chemistry , gene
Achenes of Lactuca saliva L. cv. Grand Rapids, imbibed for 6 h in water or in a 10 µ M solution of non‐radioactive abscisic acid (ABA), were cultivated on (2‐ 14 C]‐ABA (10 µ M ) for 40 to 90 h. Red irradiation (660 ± 2.5 nm, 5 min, 2 W m ‐2 ) or removal of integuments were carried out before transfer to (2‐ 14 C]‐ABA. When both treatments were applied, irradiation preceded removal of integuments. Imbibition and culture took place in darkness at 24°C. Two acidic diethyl ether phases, which contained the free acids (free phase) and the acids released after mild alkaline hydrolysis, respectively, were isolated. They were analyzed by thin layer chromatography (TLC). as well as the remaining aqueous phase. Both red irradiation and removal of integuments led to increased [2‐ 14 C|‐ABA uptake. Application of ABA during imbibition partly limited the stimulating effect of red irradiation on radioactive ABA uptake. Red irradiation stimulated [2‐ 14 C|‐ABA metabolism by achenes, favouring the formation of the polar compound found in the remaining aqueous phase. Removal of the integuments stimulated metabolism notably, leading to an increase of the radioactivity in the remaining aqueous phase. This treatment also induced the appearance of new metabolites in the free phase (compound believed to be 7'‐hydroxy‐ABA) as well as in the remaining aqueous phase. The glucose ester of ABA was the only representative compound of the ester phase. Irrespective of the experimental conditions, there was no classical oxidative metabolism indicating that oxygen was not the limiting factor.