Micropropagation of Bambusa balcooa Roxb. through axillary shoot proliferation

Bambusa balcooa is one of the most commercially important bamboo species. Regeneration of this species by sexual means is impossible because no seeds are set after flowering. Vegetative propagation is hindered due to bulky propagules, low rooting ability of the culm and branch cuttings, and seasonal specificity. This makes in vitro-based methods of regeneration important. This paper describes an efficient micropropagation protocol for multiplication of B. balcooa from nodal explants. Nodal segments were surface sterilized with 0.1% mercuric chloride for 10 min, and cultured on Murashige and Skoog (MS) medium supplemented with 4.4 mu M 6-benzylaminopurine (BAP), 2.32 mu M kinetin (Kn), and gelled with 0.2% w/v gelrite. Eighty-five percent of explants could be established in vitro with 90% of these achieving bud break. In vitro-formed shoots were successfully multiplied in MS liquid medium supplemented with 6.6 mu M BAP, 2.32 mu M Kn, 2.5% v/v coconut water, and 100 mg l(-1) myo-inositol. Subculturing shoots every 3 wk yielded a consistent proliferation rate of 4.11-fold without decline in vigor. Shoot clusters, containing 5 to 8 shoots, were rooted with 87.5% success in 1/2 MS supplemented with 5.71 mu M indole-3-acetic acid (IAA), 4.9 mu M indole-3-butyric acid (IBA), and 5.37 mu M naphthaleneacetic acid (NAA) within 3 wk. Plants regenerated in this manner were acclimatized in the greenhouse and under a shade net with 88% success.