MEDIA OPTIMIZATION FOR MAXIMUM BIOMASS PRODUCTION IN CELL-CULTURES OFPACIFIC YEW

Three cell lines of Taxus brevifolia Nutt. with differing growth rates were used to assess the effects of basal salt mixtures, carbohydrates , organic nitrogen additives, vitamin formulations, and plant growth r egulators on callus growth. Gamborg's B5 major salts provided signific antly better growth than all other salt formulations tested. The great est biomass was obtained with 1% total carbohydrate. The best carbohyd rate combination, 0.5% fructose + 0.5% sucrose, was significantly bett er than all other combinations of carbohydrates tested. A complex vita min mixture was significantly better than any one previously published vitamin formulation. Greatest rates of callus growth were obtained wi th 4.14 mu M (1 mg 1(-1) picloram, 0.46 mu M (0.1 mg 1(-1) kinetin, an d 0.38 mu M (0.1 mg 1(-1)) abscisic acid or 0.29 mu M (0.1 mg 1(-1) gi bberellic acid. Our final medium, TM5, is superior to published method s for the general callus culture of T. brevifolia. This medium has imp roved growth in three tested cell lines to provide doubling times of 3 .5 to 5.6 days, an average 5.3-fold increase over our previously publi shed medium.