CYTOHISTOLOGICAL OBSRVATIONS ON THE CALLUSFORMATION AND ORGANOGENESIS IN THIN CELLLAYER CULTURES OF RACHES OF Brassica alboglabra BAILEY

The thin cell layers from the raches of B. alboglabra Bailey were cultured onMS medium(MS +5 mg/L NAA + 5 mg/L BA + 0.25 g/L LH). After 6 days of cuIture,calli grew formthe explants, and then regenerated shoots and roots were formed fromthese calli. Both epidermal and subepidermal cells may be activated to divide. Themeristematic eellular masses were derived from the subepidermal cells.Two types oforganogenesis occured:direct and indirect organogenesis. Cytochemical observationsshowed that there was no accumulation of starch in the cells of explants before celldedifferentiation. The starch accumulated after differentiation was initiated. With themultiplication of cells and bud regeneration, the starch in the cells was consumed anddisappeared. But the starch accumulated again,when the bud primordia were formed.