In vitro Propagation of Narcissus

Adventitious shoots were induced on leaf, scale and stem explantstaken from the basal plate region of flowering-size bulbs onmedia containing 2–16 mg l^–1 6-benzylaminopurineand 0·25–4·0 mg 1^–1 1-naphthal-eneacetic acid (NAA). Only the levels of NAA had a significanteffect on the numbers of shoots produced. When trimmed and splitin half, 6 mm or more diameter in vitro shoots regenerated furtheradventitious shoots which in turn grew in size suitable forsplitting within 16 weeks. The vigour of the first generation of shoots was proportionalto the hormone levels used for their initiation. All shootseventually declined in vigour, senesced and formed dormant bulbils.Split senescent shoots regenerated only a few secondary shootswhich quickly became senescent. A total of 500–2000 bulbilscould be obtained from each initial bulb within 18 months. Bulbilsrequired 10 weeks at low temperature before planting to breakdormancy. Histological observations showed that in twin scales and splitshoots, adventitious shoots were regenerated from at least twosuperficial layers of menstematic cells near to the basal plate.This multicellular mode of origin suggests that plants multipliedfrom in vitro adventitious shoots could be as genetically uniformas those from natural vegetative increase. Narcissus, tissue culture, propagation, adventitious shoots, histology