ENHANCED BUD REGENERATION AND BULB FORMATION OF SPRING SNOWFLAKES LEUCOJUM VERNUM IN LIQUID CULTURES

Most geophytes are propagated vegetatively utilizing their potential to develop storage organs. The propagation rate of cultivars of Spring Snowflakes (Leucojum vernum) was very low and tissue culture was used in an attempt to increase bulb production. Three selected cultivars, (early, medium and late flowering), were cultured in semi-solid medium with Naphtaleneacetic acid (NAA) and Benzyladenine(BA), however their propagation rate was low (4-5 bulbs/explant) and growth was slow. Liquid cultures and growth retardants (inhibitors of GA biosynthesis), were found to augment bulb production, utilizing bud cluster development in geophytes. In vitro bulblets were used as the explant source for enhanced regeneration. Scales, twin-scales and basal plate sections were cultured in liquid Murashige and Skoog (MS) with 5 μM NAA and BA each and i) n the presence or absence of Uniconazole (Majic^®). The presence of 0.5-2.5 mg/l Majic^® yielded clusters consisting of 35-40 bud and meristemoids, while in its absence only 8-10 buds were observed. Bud clusters were separated by a grid cutter for further biomass increase, and for testing the effects of inoculum size and number of cycles in the same medium on growth. Clusters were also sub-cultured to a bulb inducing 1/2 MS minerals medium with 10μM Indolebutyric acid (IBA), 6% sucrose and 1.0 mg/l Majic^® in liquid shake cultures or bioreactors. Bulblets produced were separated, sub-cultured to hardening 1/2 MS minerals semi-solid medium with 10 μM IBA and 0.5 mg/l activated charcoal. Bulblets 4-6 mm in diameter were transplanted to the greenhouse with 95% survival rate. Plants that were left to grow for a second year successfully produced bulbs with a diameter of 10-12 mm and will be tested for their fidelity. Liquid cultures in bioreactors and the growth retardant Majic^® greatly enhance bud regeneration and bulb production in Spring Snowflakes.