Abstract: Cytological observations showed that random dedifferentiation of parenchymatous cells produced embryogenic cells and then gave rise to two types of meristems. They were meristematic cell aggregations and meristematic nodules, which might further form organs primordia. BA had a determinative effect on bud differentiation of the callus, initiating growth showing meristiatic monopolarity leading to bud primordium formation. NAA had a important effect on root differentiation. With NAA and BA, ZT accelerated cell division and organ primodium rormation. LH accelerated bud differentiation but inhibited root formation from vascular nodules. And YE restrained further differentiation of both meristems.