Abstract:
The mitotic inhibitor colchicine was applied to stem explants of diploid Exacum ritigalensis fBinara) to observe callus and adventitious shoot formation. The objective of the study was to finJeffective durations and concentrations of colchicine for callus formation. The stem explants (1 cm) of Exacum ritigalensis tvere introduced to Murashige and Skoog (MSJ basal medium containing 2 mgL-t BAp and 0.1 mgLt 2,4-D ivith different colchicine concentrations [0, 10, 20,30,40 and 50 mgl 1) for cal]us induction. They were naintained on growth medium with colchicine in different time durations (0, 12,24,36 and 4g hours) and rransferred in to MS basal medium with 2 mgL-t BAP and 0.1 mgl-r 2,4-D for further growth. All :reatments were arranged as factorial completely randomized design IFCRD) with five replicates. Data
"r'ere collected one month after colchicine treatment. The area of the callus [cm2) was measured. statistical analysis was carried out using Duncan's multiple range test of sAS software fversion g.1.3J. The
'-olour variation [white, yellow and brown) and texture (compact or softJ were observed and analyzed lsing Mann-Whitney test' Increased colchicine concentration and exposure time duration showed that the :eduction of callus formation from stem explants significantly than control. colchicine concentrations of l0 and 20 mgL'1 in 1,2 hours and colchicine concentrations of 10 mgl-r for 24 hours produced calluses
,', hich have potential regenerate mutant plantlets.
