Micropropagation of Bambusa oldhamii Munro in heterotrophic, mixotrophic and photomixotrophic systems

Abstract

Photomixotrophic micropropagation systems have been associated with improved development of several plant species. In this work, we established an efficient protocol for the in vitro micropropagation of Bambusa oldhamii Munro by studying the influence of the rainy and dry seasons on plant tissue contamination, the effects of the gaseous atmosphere inside the culture flasks, and the effects of radiation conditions on plant morphogenetic events. Explants were collected from March to December 2016. The conditions consisted of 100% blue (455 nm), 100% red (630 nm), 30% blue + 70% red, and 30% red + 70% blue LED light or fluorescent light only (as a control). For induction of axillary sprouting, the explants were inoculated in MS media + 2.27 µM thidiazuron or 3.40 µM paclobutrazol. The best growth responses were observed for material collected from June to July. There was an increase of 81.79% in the number of leaves under the 30% blue + 70% red LED treatment in comparison to the control. The facilitation of gas exchange resulted in improved shoot production, with an increase of 70.80% under 30% red + 70% blue LED light in comparison to that of treatments without gas exchange. The blue LED light had an important photomorphogenic effect on the development of bamboo explants into shoots, as shoot proliferation increased. The results obtained will aid in the development of protocols for the in vitro culture of other species of bamboo as well as for the establishment of an efficient protocol to address rooting for this and other bamboo species. Minimum temperature and compensated temperature resulted in significant impact on in vitro establishment. Blue + red combined with natural ventilation resulted in efficient shoot proliferation. Paclobutrazol increased the pigment content.