The 2009 ASHS Annual Conference

Present studies were undertaken to establish the mass propagation systems by examining adequate environmental conditions for culturing prothalli of Pteris cretica. Chopped prothalli were inoculated on 3 kinds of medium: 1/8, 1/4, 1/2, 1, and 2X MS with 3% sucrose and 0.8 agar, 0.3% Hyponex (N:P:K=6.5:6:19), and Knop medium. The multiplication and growth of prothalli was highest with Hyponex medium. To see the effects of sucrose concentrations prothalli were again inoculated on Hyponex and MS medium containing 0 ~ 5% sucrose, and the highest growth was obtained with Hyponex with 1% sucrose. Most prothalli did not survive on MS medium containing sucrose, but in some prothalli the formation of parenchyma tissues, not gemmae, was observed. Divided in groups or chopped prothalli were placed on 3 media and results showed that division was better with MS, whereas chopped was with Hyponex. The agar concentration of 0.6% was most effective in prothallus multiplication. Solid and liquid medium(stationary or shaking) were employed in this experiment and solid medium proved to be effective in prothallus multiplication. The prothalli continued to multiply by the formation of gemmae in liquid shaking culture, but in solid culture parenchyma tissues were formed. This indicates that liquid shaking culture might be preferred for prothallus proliferation if cultured more than 8 weeks. In conclusion, solid culture should be used if the sporophyte formation by prothalli is wanted, but if mass propagation of prothalli is  desired, liquid shaking culture is favored even if it takes longer time.