Application of a novel disposable film culture system to photoautotrophic micropropagation of Eucalyptus uro-grandis (urophylla x grandis)

To overcome various disadvantages of conventional culture vessels for plant micropropagation, we previously developed the photoautotrophic micropropagation technique, with special mention for the first practical film culture system, the 'Miracle Pack' (MP), which was made of fluorocarbon polymer film (Neoflon((R)) PFA film) and supported by a polycarbonate frame. While the PFA film has superior thermal stability, high light transmittance, and high gas permeability, making the MP system (MP-PFA) superior to conventional culture vessels for the micropropagation of various plant species, its high cost is a disadvantage. In this study, a possible alternative of lower-cost OTP (R) film made of TPX (4-methyl-1-pentane polymer) and CPP (a polypropylene), which possesses similar characteristics to PFA film, is evaluated to develop a novel disposable film culture vessel, termed 'Vitron,' for culturing Eucalyptus (urophylla x grandis) plantlets. The three film culture systems, MP-PFA, MP-OTP (MP with OTP film), and Vitron, were placed under CO2 enrichment, low photosynthetic photon flux density (PPFD; 45 mu mol m(-2) s(-1)), and sugar-free medium, using phenol resin foam (Oasis((R))) as a substrate. In vitro and ex vitro growth and development of Eucalyptus shoots from the four-leaf stage to the rooting stage were compared for all three culture systems. The effects of the duration and concentration of CO2 enrichment on in vitro growth of Eucalyptus cultured in the Vitron film system were also examined. The best growth and quality of Eucalyptus plantlets was obtained for the Vitron vessel placed in 3000 ppm CO2 enrichment for 24 hours per day at low PPFD with sugar-free liquid medium and Oasis as substrate. Results of this study suggest that the novel Vitron culture system is suitable for the photoautotrophic micropropagation of Eucalyptus.