Gibberellins and Growth Inhibitors in Spring Bleeding Sap, Roots and Branches of Juglans regia L.

The main gibberellin found in the spring bleeding sap of thewalnut tree was identified as GA₁₉ and quantified by gas chromatography-selectedion monitoring (817 pg/ml). The second minor gibberellin (12pg GA₃-equiv./ml) was chromatographically similar to GA₅₃. Bothgibberellins occur in their free forms and as neutral ester-likeconjugates. In the roots, these free gibberellins and an additionalgibberellin glucoside-like component were found in late winter. In the bleeding sap, branches and roots, abscisic acid was identifiedby gas chromatography and mass spectrometry. In the sap, itsamount was determined to be 34 ng/ml. ABA was not found in aconjugated form, but the branches contained a neutral ester-likeconjugate of 4'-dihydrophaseic acid, an ABA metabolite, whichafter hydrolysis was identified by combined gas chromatography-massspectrometry. (Received March 28, 1981; Accepted November 16, 1981)