Identification of endogenous gibberellins in inflorescence of Ornithogalum thyrsoides

Endogenous gibberellins (GAs) were extracted from inflorescence of Ornithogalum thyrsoides and identified by using combined gas-chromatography / mass spectrometry (GC/MS). Three 13-hydroxylated GAs, GA₁₉, GA₂₀ and GA₅₃, and thirteen 13-non-hydroxylated GAs, GA₄, GA₇, GA₉, GA₁₂, GA₁₅, GA₂₄, GA₂₅, GA₅₁, GA₆₁, GA₁₁₂, GA₁₁₅, 1,2-didehydro GA₉ (which is a novel GA, and has been assigned as GA₁₂₀), and GA₁₂₀ - isolactone were detected. The presence of these GAs suggests that both the early-13-hydroxylation GA biosynthesis pathway and the early-13-non-hydroxylated GA biosynthesis pathway were operating in the inflorescence of Ornithogalum. The presence of GA₇, GA₉ and GA₁₂₀ suggests that GA₁₂₀ could be considered as a metabolic intermediate in the conversion of GA₉ into GA₇ in O. thyrsoides.