Identification of Gibberellins A(1), A(5), A(29), and A(32) from Immature Seeds of Apricot (Prunus armeniaca L.)

Gibberellins (GAs) A₁, A₅, and A₂₉ were identified, and also GA₃₂ was confirmed, as endogenous GAs of immature seeds (3-4 weeks after anthesis, 0.25-0.5 gram fresh weight) of apricot (Prunus armeniaca L.) based on capillary gas chromatography (GC), retention time (Rt), and selected ion monitoring (SIM), in comparison with authentic standards. Fractions subjected to GC-SIM were purified and separated using sequential solvent partitioning → paper chromatography → reverse phase C₁₈ high performance liquid chromatography (HPLC) → bioassay on dwarf rice cv Tan-ginbozu. Two other peaks of free GA-like bioactivity (microdrop and immersion dwarf rice assays) were eluted from C₁₈ HPLC at Rts where GA_4/7 and GA₈ (or other GAs with similar structures) would elute. Also, three unidentified GA glucoside-like compounds (based on bioactivity on the immersion assay, and no bioactivity on the microdrop assay) were noted. There were very high amounts of GA₃₂ (112 ng of GA₃ equivalents per gram fresh weight), and minor amounts (0.5 ng of GA₃ equivalents) for each of GA₁ and GA₅, respectively, based on the microdrop assay.