Changes in Gene Expression from Diploid to Autotetraploid Status of Lycopersicon esculentum

The cytokinin activity of the root exudate, the leaves, and the apices of vegetative and flowering white lupin plants (Lupinus albus L.) was investigated. The level of cytokinin activity in the root exudate decreased over the 11-week experimental period. Four peaks of cytokinin activity were recorded in the root exudate of 8-week-old plants after fractionation on Sephadex LH-20. Two of these peaks co-eluted with zeatin and zeatin riboside. It is suggested that the remaining peaks represent nucleotide and glucoside cytokinins. The cytokinin levels in extracts of the mature leaves fluctuated slightly over the experimental period. Three peaks of activity co-eluting with zeatin, zeatin riboside and the glucoside cytokinins were recorded in extracts of mature leaves of 8-week-old plants. In the apices cytokinin activity could only be detected in the inflorescences of flowering plants. It would appear that cytokinins produced by the roots accumulate in the fully expanded mature leaves, but are utilized in the rapidly growing apical region and in young expanding leaves.