CHANGES IN CYTOKININ ACTIVITY IN THE RIPENING TOMATO FRUIT

The endogenous cytokinin activity of tomato fruits (Lycopersicon esculentum var. Heinz 1439) as measured by the Amaranthus bioassay decreases from 10.35 μg benzylaminopurine equivalents/1000g mature green fruit to 0.15 μg benzylaminopurine equivalents/1000g for the fully ripe fruits. Chromatography of the various tomato fruit extracts indicates changes in cytokinins during the ripening process. Liquid chromatography and gas chromatography of the tomato extracts indicate the presence of zeatin, zeatin riboside and isopentenyl adenine riboside like compounds in the extracts. The presence of zeatin riboside was confirmed by mass spectroscopy.