Abstract:Nitrogen and phosphorus have a great influence on cell growth and of development in PorPhyr. This paper discussed the effects of defferent sources of nitrogen, varied concentration of nitrogen and phosphorus, and different cell densities on cell survival ratio and cell growth when ce1ls isolated from thalli on PorPhyr yezoensis cultured in vitro. The results showed that the isolated ce11s grew better in NO, -N than in NH' -N media- For the first 3 days, the cultured ce1ls had some endurance to vary concentration of N and P. After 3 days, the concentration of N/P would innuence the cell survival ratio. The cel1 survival ratio was the highest when the concentration of N/P was 18- 20/1. 8- 2.0 mg l-1. And the ce11 division speed would increase when the concentration of N/P promoted. The cell density of 1 - 2 X 105 cells/ml was better to cell survival ratio and growth, if cell density was too higher, the survivaI ratio would be low and cell growth would be slow. The experiments had laid the foundation of the cell culture and breeding with large sca1e in Porphyra yezoensis.