Effects of Vitrofural, BAP and meta-Topolin in the in vitro culture of Dendrocalamus asper

Dendrocalamus asper is an important tropical bamboo native to the Asian continent. As for bamboos in general, conventional propagation methods for this species are not efficient for a large scale plantlet production. Therefore, tissue culture based biotechnologies comprise effective tools to achieve a mass propagation of selected genotypes. In the present study we evaluated the efficiency of the biocide Vitrofural for the establishment of contaminant-free in vitro cultures; the effect of Benzylaminopurine (BAP) in the culture induction, as well as the effects of meta-Topolin (mT) in the proliferation and development phase of the cultures. Nodal segments collected from a field-plant were subjected to sterilization procedure and inoculated in gelled MS basal medium (MSB), containing or not Vitrofural and supplemented with BAP (5, 10, 15, 20 µM). Seven subcultures (each subculture lasted 45 days) were performed in MSB medium supplemented with mT (0, 5, 10, 15 and 20 µM) and the proliferation efficiency assessed. Vitrofural decreased the culture contamination, thus allowing the establishment of contaminant-free organogenic cultures. A curvilinear trend was evidenced for the effect of BAP concentration on bud sprouting, with the highest values estimated at concentrations between 15 and 20 µM. For the proliferation phase, it was evidenced that increasing concentrations of mT caused a reduction in culm size and an increment in branch size, with an overall increase in the proliferation rate of cluster. This study provides new information on the micropropagation of D. asper and presents the first report of a positive effect of mT in the micropropagation of a bamboo model plant.