Effectiveness of high cytokinin levels on micropropagation

Abstract

The in vitro propagation of strelitzia (Strelitzia reginae Banks) seedlings may have limitations during multiplication, and alternatives to optimize this process are required in order to contribute to improve the propagation of many other species. In this way, the objective was to optimize the multiplication process of strelitzia by modifying the cytokinin concentrations. Shoots that are 2.0 cm long obtained from in vitro embryo germination were excised and inoculated in MS medium supplemented with 0, 5, 10, and 20 μM 6-benzylaminopurine (BAP) or 0, 5, 10, and 15 μM thidiazuron (TDZ) and kept for 60 days in a growth room. The results showed that 20 μM BAP provided a better shoot formation, with an average of 1.46 shoots explant‑1, being observed in some explants up to 4.0 shoots which was 46% higher as compared with the control. Besides the increase in shoot number, a reduction in shoot length (2.71 cm) was observed, as well as an increase in oxidation of the culture medium. Otherwise, the use of TDZ was not effective to stimulate the formation of new shoots. The results showed that 20 μM BAP can be used for in vitro multiplication of strelitzia.