EFFECT OF PHOTOPERIOD, PLANT GROWTH REGULATORS AND EXPLANT SIZE ON IN VITRO BULBLET FORMATION IN SNOWDROP

Abstract
Plant tissue culture techniques have a widespread usage in rapid, easy and continuous propagation of bulbous and tuberous plants, called geophytes. The genus Galanthus (commonly called snowdrops), perennial bulbiferous geophytes belonging the Amaryllidaceae family, contain several high-value alkaloids with pharmaceutical use to treat Alzheimer’s disease. The objective of this study was to assess the effect of photoperiod, plant growth regulators and explant size on in vitro bulblet formation in snowdrop (Galanthus woronowii). Bulb twin-scale explants were cultured on MS medium containing different combinations of BAP with various concentrations of NAA, IAA and IBA under 16/8 h light/dark and 24 h dark conditions. Effect of plant growth regulators was significant on the number of bulblet, bulblet diameter, bulblet weight, and the number of bulblet bigger than 5 mm in diameter. Continuous dark application resulted in highly significant increases in bulblet formation, as compared to light treatment. The maximum number of bulblet (4.83) was recorded from 4-piece explants treated with 2 mg l-1 BAP+0.1 mg l-1 NAA hormone combination kept in 24 h dark condition. Dark treatment resulted in an increase of %57.33 in the number of bulblet bigger than 5 mm in diameter. Explant size showed no effect on any of the attributes studied. In conclusion, this study revealed that 24 h dark treatment has a very important positive effect on in vitro bulblet formation in snowdrop.