HISTOLOGICAL OBSERVATIONS OF ADVENTITIOUS BUD DEVELOPMENT IN PINUS-NIGRA

Mature zygotic embryos of Pinus nigra ARN. were treated with BA to for m adventitious buds. After 4 days of treatment we observed appearance of dense cytoplasmic cells in subepidermal layer of cotyledons, follow ed by periclinal division of these cells. After 8 days 3-4 layers of h ighly dividing cells were observed giving rise to multi-celled structu res - meristemoids. Further proliferation of these cells resulted into formation of adventitious bud primordia and later into adventitious b uds.