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Abstract
The presence of gibberellin A29 (GA29) in extracts of pericarp of immature prune, was established by combined gas chromatography-mass spectrometry (GC-MS). Another gibberellin (GA) in the extract was determined by GC-MS to be a di-hydroxy A9 derivative different from any of the 46 GAs of known structure. An inhibitor of wheat coleoptile elongation present in pericarp and seeds was tentatively identified as abscisic acid (ABA), based on Rf values on thin-layer chromatograms (TLC) and retention times of the methyl ester on gas liquid chromatographic (GLC) columns.
Abstract
Foliar applications of 2-chloroethyl-tris-(2-methoxy ethoxy)-silane (CGA 13586) caused abscission of olive fruits and, to much lesser extent, leaves due to its release of ethylene upon contact with water. Maximum reduction in fruit removal force occurred 7 to 8 days after application and seemed to be a direct effect on the abscission layer. The ethylene-releasing reaction rate was affected by the solution pH, increasing with higher pH values. Lower pH (ca. 6) gave greater abscission than did higher pH levels since the compound presumably hydrolyzed too rapidly in the latter for the ethylene released to cause abscission. CGA 13586 produced considerably higher initial ethylene release in comparisons with (2 chloroethyl)phosphonic acid (ethephon) but it was not as long lasting.