Abstract:

The calli formation and organ regeneration from different explants in vitro of Betula platyphylla were discribed.The calli of stem and petiole mainly originated from cortex parenchymatous cells in wound, and that of leaf produced from epidermis and the parenchymatous cells under it. The meristematic nodules were formed at high frenquency in developing callus . They further developed into vascular nodules which could grow at single direction and form adventitious roots. The adventitious buds occurred in the meristematic cell mass in the surface area of calli where the suberized periderm was lacking .In axillary bud proliferation way, adventitious buds originated from the epidermis and underepidermis of stem in axillary and nearby areas. The induced adventitious roots were mainly initiated from the ray cell near the cambium.It seemed that callus inhibited rooting.

Key words: Betula platyphylla, Culture in vitro, Morphogenesis