Metabolism of [(3)H]Gibberellin A 20 by plants of Bryophyllum daigremontianum under long- and short-day conditions.

[(3)H]Gibberellin A20 ([(3)H]GA20), a native gibberellin of this plant, was injected into mature leaves of Bryophyllum daigremontianum (Hamet et Perr.) Berg. under long- and short-day conditions. It was converted, in order of decreasing yields, to GA29, 3-epi-GA1 (pseudo GA1), C/D-ring-rearranged GA20, and two minor, unidentified metabolites. Identifications were made by gas-liquid chromatography with radioactive monitoring using three different phases. Metabolism to 3-epi-GA1 was greater under short days, particularly in the treated leaf pair, although the absolute amount of GA29 was greater than that of 3-epi-GA1 under both photoperiods. The levels of radioactive metabolites in the shoots above the treated leaf pair gradually increased over a 51-day period, GA29 reaching 5 times the contten of 3-epi-GA1.