The identification and metabolism of GA9 and its metabolites in seed coats and shoots of pea,line G2

³H]gibberellin A₉ was applied to shoots or seed parts of G2 pea to produce radiolabeled metabolites. These were used as markers during purification for the recovery of endogenous GA₉ and its naturally occurring metabolites. GA₉ and its metabolites were purified by HPLC, derivatized and examined by GC-MS. Endogenous GA₉, GA₂₀, GA₂₉ and GA₅₁ were identified in pea shoots and seed coats. GA₅₁-catabolite and GA₂₉-catabolite were also detected in seed coats. GA₇₀ was detected in seed coats following the application of 1 g of GA₉. Applied ³H]GA₉ was metabolized through both the 13-hydroxylation and 2-hydroxylation pathways. Labeled metabolites were tentatively identified on the basis of co-chromatography on HPLC with endogenous compounds identified by GC-MS. In shoots ³H]GA₅₁ and ³H]GA₅₁-catabolite were the predominant metabolites after 6 hrs, but by 24 hrs there was little of these metabolites remaining, while ³H]GA₂₉-catabolite and an unidentified metabolite predominated. In seed coats ³H]GA₅₁ was the initial product, later followed by ³H]GA₅₁-catabolite and an unidentified metabolite (different from that in shoots), with lesser amounts of ³H]GA₂₀, ³H]GA₂₉ and ³H]GA₂₉-catabolite. ³H]GA₇₀ was a very minor product in both cases. ³H]GA₉ was not metabolized by pea cotyledons.Edited by T.J. Gianfagna.Author for correspondence