Application of image analysis to fed-batch cultures of somatic embryos

Nutrient limitation and inhibitor accumulation have been shown to impede the development of somatic embryos of carrots in batch cultures. To improve the development of embryos, semicontinuous cultures with daily medium replenishment were performed. An image analysis system capable of identifying normal and abnormal embryos was used to facilitate the kinetic study. At a high daily medium replenishment rate of 20%, the biomass production was also higher, but not the embryo concentration. Total embryo and torpedo embryo concentrations were both higher at a 10% medium replenishment rate than at 5% and 20%. The profiles of embryo concentrations under three medium replenishment rates appeared similar until a late stage of cultivation; however, statistical analysis of the morphological features distribution revealed that significant differences were discernible earlier. For the formation of mature embryos, the optimal daily medium replenishment is judged to be in the range of 10-20%. In this study, more than 20 000 embryos were classified and counted. The information on population kinetics and statistical comparison were made possible by the availability of our image analysis system.