Establishment of an efficient micropropagation and callus regeneration system from the axillary buds of Bambusa ventricosa

Abstract

Based on the screening of various hormone combinations, we have established an efficient micropropagation and callus regeneration system from the axillary buds of B. ventricosa. We found that 6-benzyladenine (6-BA) had a dominant role in promoting bud sprouting, multiple bud induction and proliferation in B. ventricosa. Meanwhile α-naphthaleneacetic acid (NAA) was found to be an effective factor of inducing rooting in proliferated buds. The Murashige and Skoog medium containing 22.2 µM 6-BA was optimal for bud initiation, and the MS medium containing 26.6 µM 6-BA provided a good result for multiple bud induction. However, for buds proliferation MS medium containing 22.2 µM 6-BA, 0.23 µM Thidiazuron (TDZ: N-phenyl-N-[(1, 2, 3-thidiazol-5-yl) urea]) and 0.27 µM NAA was found to be very effective. The optimal medium for rooting of proliferated bud was MS medium containing 2.7 µM NAA, 4.9 µM indole butyric acid and 4.4 µM 6-BA. Based on the establishment of an efficient micropropagation system, we investigated the frequencies of callus formation from buds of in virto raised plantlets under different culture conditions. We showed that media containing 27 µM 2, 4-dichlorophenoxyacetic acid (2, 4-D), 2.7 µM NAA and 0.0045 µM TDZ effectively produced callus. The callus induction rate varied between it to 60 percent. TDZ was found to be a main factor influencing the callogenesis of B. ventricosa. Medium containing 22.6 µM 2, 4-D, 2.2 µM 6-BA and 5.4 µM NAA was preferred for callus amplification among the four tested subculture media. Plants were successfully regenerated on a MS medium containing 13.3 µM 6-BA and 2.7 µM NAA, subsequently acclimatized and transplanted to an experimental pod.