EFFECT OF OSMOLARITY AND MEDIUM COMPOSITION ON CALLOGENESIS, CAULOGENESIS AND RHIZOGENESIS OF BRASSICA-OLERACEA L VAR BOTRYTIS HYPOCOTYL FRAGMENTS

Callus formation by fragments of cauliflower hypocotyls was favoured b y raising culture medium osmolarity above -0.38 MPa. Increase in sucro se concentration while diminishing macronutrients inhibited callus ini tiation and growth. Root formation by the same material required a low medium osmolarity (-0.19 MPa). Reducing sucrose concentration in the classical Murashige and Skoog rooting culture medium favoured root for mation. Adventitious bud formation was also depending upon medium osmo larity besides the need for a cytokinin. Reducing too much the osmotic potential of the medium had an unfavourable effect on bud neoformatio n. The importance of sucrose in all these processes is pointed out.