IN-VITRO INDUCTION OF MULTIPLE BUDS IN TISSUE-CULTURE OF JUNIPERUS-EXCELSA

In the present experiment adventitious buds were induced on excised co tyledon segments and embryo explants of Juniperus excelsa on both Erik sson (1965) and Murashige and Skoog (1962) basal media containing eith er 0.5 or 1 mg l(-1) BAP (6-benzylaminopurine) with or without NAA. Wh en 0.02 mg l(-1) NAA was added to Eriksson basal medium containing 0.5 mg l(-1) BAP as many as 92 adventitious shoots were formed per cotyle don segment. Embryo explants showed the best response when the same co ncentration of NAA was added to Murashige and Skoog medium containing 1 mg l(-1) BAP. The presence of NAA in Murashige and Skoog basal mediu m suppressed the morphogenetic response of cotyledon explants and succ essive growth of the buds. When the proliferated explants with numerou s scale-like organs were transferred to respective basal media contain ing neither BAP nor NAA and when all explants with overcrowded propagu les were divided into two or more sections, the growth of the propagul es was further stimulated. Better rooting of adventitious shoots was a chieved when shoots were pre-treated with IBA (1 mg l(-1)) and NAA (0. 5 mg l(-1))or activated charcoal (1% w/v) for three weeks and incubate d in a covered seed tray filled with non-sterile compost for four mont hs. Untreated shoots also rooted after four months when maintained on the same basal medium. These aseptically rooted shoots needed more car eful acclimatisation. (C) 1997 Elsevier Science B.V.