Identification of a Novel Gibberellin (GA85) in Very Young Seedlings of Brassica campestris cv. Tobin

A new gibberellin (GA) was identified from extracts of cotyledons of 7 day-old canola seedlings (Brassica campestris cv. Tobin). This GA is 12α-hydroxy-GA₁ and has been assigned the trivial name of GA₈₅. Isolation was monitored by the Tan-ginbozu dwarf rice micro-drop assay after each high-performance liquid chromatography (HPLC) step. Identification was based on Kovats retention index (KRI) and the mass spectrum of the methyl ester, trimethylsilyl ether (MeTMSi) derivative after analysis by gas chromatography-mass spectrometry (GC-MS) in comparison with an authentic sample of 12α-hydroxy-GA₁. Based on quantitation by the dwarf rice micro-drop assay, GA₈₅ is one of the major biologically active GAs in cotyledons of young canola seedlings.