AUTOCLAVED AND FILTER STERILIZED LIQUID-MEDIA IN MAIZE ANTHER CULTURE- SIGNIFICANCE OF ACTIVATED-CHARCOAL

Medium sterilization techniques (autoclaving, filter sterilization and separate sterilization of medium components), combined with precultur e exposure to activated charcoal (AC) were evaluated for effects on ma ize anther culture response. The addition Of AC to filter sterilized m edium had no effect on the number of embryo-like-structures (ES) produ ced. For autoclaved medium, pre-culture AC treatment resulted in a 3-f old increase in ES yield over medium lacking AC. When AC was included, autoclaved medium was more productive than filter sterilized medium. Autoclaved media without AC gave lower response than filter sterilized medium. Separate sterilization of sucrose or FeEDTA was beneficial fo r media autoclaved in the absence of AC. However, when all components were autoclaved together in the presence of AC, there was no advantage to separate sterilization. The maximum ES frequency (224.6 ES/100 ant hers) was obtained with the genotype ETH-M 52 cultured in autoclaved m edium which had been exposed to AC (5 g/L) for 96 h prior to culture i nitiation. It is supposed that the higher ES frequencies observed with AC-treated, autoclaved media were due to a) the availability of gluco se and fructose following heat-induced hydrolysis of sucrose and b) th e AC-mediated adsorption of inhibitory compounds produced during autoc laving.