ENDOGENOUS GIBBERELLINS FROM CALLUS-CULTURES OF MAIZE

This paper reports the identification of gibberellin A(1)(GA(1)), GA(1 7), GA(19), GA(20), GA(29), and GA(53) from extracts of normal (wild-t ype) maize callus using full-scan GC-Mass Spectrometry and Kovats rete ntion indices (KRIs). In addition, evidence is presented for the prese nce of GA(8) based on its molecular ion at the appropriate KRI. In a p reliminary experiment, the presence of GA(3), GA(5), and GA(44) was su ggested, based on GC-selected ion monitoring (SIM); however, the prese nce of these GAs was not confirmed by full-scan GC-Mass Spectrometry. The information represents the first identification of GAs from maize callus. All of the identified GAs are members of the early-13-hydroxyl ation pathway, a biosynthetic pathway that leads to bioactive GA(1). G A(1), GA(8), GA(19), GA(20), and GA(29) were quantified from GC-SIM is otopic dilution data. GA(17) and GA(53) were quantified from GC-SIM da ta by comparing the ion intensity from each gibberellin to a known amo unt of a GA(19) standard. The levels of the identified GAs ranged from 6 pg g(-1) fr. wt to 210 pg g(-1) fr. wt.