SIMILAR EFFECTS OF COLCHICINE AND LOW TEMPERATURE ON INITIATION AND ELONGATION OF STEMS IN BULBLETS DEVELOPED ON SCALES OF 'WHITE AGA' (LILIUM x FORMOLONGI) CULTURED IN VITRO

Abstract

Factors affecting the initiation and elongation of stems from bulblets developed on the scales of ‘White Aga’ (Lilium x formolongi) were examined by low-temperature treatment of bulbscales cultured in darkness or by culturing them in a medium with colchicine at 25°C. Scale explants excised from in vitro-cultured bulblets were cultured for a total of 180 days in darkness. First, they were cultured in MS medium with 0.54 µM NAA and 4.4 or 44 µM BA at 25°C for 30 days, and then further subcultured under the following conditions: (1) continuously cultured at 25°C for 150 days (control) on MS medium with 4.4 µ µ µ µM BA; (2) cultured at 8°C for 60 days, followed by culture at 25°C for 90 days (low-temperature treatment) on MS medium with 4.4 µM BA; (3) cultured on MS medium with 4.4 µM BA and 1 µ µ µ µM or 10 µM of colchicine at 25°C for 30 days, followed by culture on MS medium with 4.4 µM BA at 25°C for 120 days (colchicine treatment). Stem elongation from bulblets developing on the scales was observed in bulblets subjected to both low-temperature and colchicine treatment. Since both treatments, which inhibit the polymerization of microtubules (MTs) and stimulate the depolymerization of MTs, affected stem elongation from bulblets, there might be some relationship between the inhibition of polymerization as well as the stimulation of depolymerization of MTs and the induction and elongation of stems in bulblets.