STIMULATION BY SUCROSE OF NARCISSUS BULBIL FORMATION INVITRO

Factors influencing the in vitro formation of bulbils by micropropagated shoots of five genotypes of Narcissus were investigated. Few bulbils developed in shoot proliferation conditions (3% sucrose) but increasing the sucrose concentration to 6% or 9% increased the percentage of shoots forming bulbils to 49% and 71% respectively. Bulbil formation was inhibited by 4.4 x 10(-6) M benzylaminopurine (BAP) in the presence or absence of 0.54 x 10(-6) M napthaleneacetic acid (NAA) and was slightly stimulated by NAA in the absence of BAP. Bulbil growth was markedly stimulated by an elevated sucrose concentration while BAP was inhibitory and NAA had little effect. Bulbils produced on a high sucrose, BAP-free medium transferred readily to ex vitrium conditions and showed continued leaf growth. Ex vitrium bulbil leaf growth was greatly reduced by the use of BAP in the in vitro phase.