When barley aleurone layers were incubated with (3)H-Gibberellin A1 ((3)H-GA1), the hormone was converted to (3)H-GA-X (not identified), (3)H-GA8 and two other compounds tentatively identified as (3)H-GA1-glucoside, and (3)H-GA8-glucoside. Uptake and metabolism of the (3)H-GA1 were markedly enhanced by simultaneous treatment with abscisic acid (ABA). Uptake of (3)H-GA1 from the medium containing ABA was linear over a 24-h period, whereas in the absence of ABA, uptake of (3)H-GA1 leveled off after 5 h. After 24 h, aleurones treated with (3)H-GA1 and (3)H-GA1 plus ABA, had taken up 9 and 24%, respectively, of the original (3)H-GA1 provided. Metabolism of (3)H-GA1 proceeded at a linear rate in the presence of ABA. The amount of (3)H-GA1-metabolites which had accumulated by the end of a 24-h incubation appeared to be linearly correlated to the logarithm of the ABA concentration. Gibberellins A8 and-A8-glucoside did not reverse GA1-enhanced synthesis of α-amylase.
Uptake and metabolism of 1,2-[(3)H]gibberellin A(1) ([(3)H]GA(1), I) and its 3-hydroxy epimer ([(3)H]pseudoGA(1), II) by barley (Hordeum vulgare L.) half-seeds were measured after 24 hours of incubation, in the presence or absence of abscisic acid in the media. Uptake of both compounds was enhanced by abscisic acid, and abscisic acid enhanced the extent of metabolism of [(3)H]GA(1). However, [(3)H]pseudoGA(1) was not metabolized, even in the presence of abscisic acid. The significance of the stereo-chemistry of the 3-hydroxyl position is discussed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.