The Influence of hydroxy or methoxy group position in the benzyl ring of 6-benzyl-9-tetrahydropyran-2-yl-purines on their biological activity in classical cytokinin bioassays. Comparison of the impact of hydroxy (A–C) and methoxy (D–F) groups substituted in ortho- (circles), meta- (triangles), and para- (diamonds) positions, respectively, on: the retention of chlorophyll in excised wheat leaves (A, D); the stimulation of cytokinin-dependent tobacco callus growth (B, E); and the dark induction of betacyanin synthesis in Amaranthus cotyledons (C, F).

The Influence of 9-tetrahydropyran-2-yl and 9-tetrahydrofuran-2-yl groups on the biological activity of 6-benzyl-(3-hydroxybenzylamino)purine in classical cytokinin bioassays. (A) The effect on chlorophyll retention in excised wheat leaf tips; (B) the growth of cytokinin-dependent tobacco callus; (C) the effect on dark betacyanin synthesis in Amaranthus caudatus cotyledon-hypocotyl explants.