Abstract: The present paper reports the establishment of rice cell suspension culture system, including callus induction and proliferation, isolation of single cells and small aggregates, cell suspension culture and callus re-formation, as well as regeneration of plantlets. The results have been obtained as follows: 1. The compositions of the different media used for callus induction, callus proliferation, cell suspension and plant regeneration are summarized in Table 1.2. Two kinds of disifectants, mercuric chloride and sodium hypochlorite, were used for surface sterilization of brown rice. The percentage of callus formation and callus yields were much higher when sodium hypochlorite was used (Fig. 3). We suggest that the disinfactant is one of the important factors that affect callus formed at the initial stage has an influence upon subsequent isolation of cells and suspension culture and even plant regeneration. 3. Table 3 shows that addition of yeast extract to the medium improves callus yield greatly and the efficiency of callus formation to a lesser extent. 4. Both medium Ⅱ (modified B5 medium) and N6 medium were suitable for cell suspension culture, but medium II was more effective for cell growth and callus re-formation (Fig. 4 and Table 4). 5. Effect of 2, 4-D on cell growth was tested at the concentration range among 0, 10-6, 10-5, 10-4 to 10-3 M. The results indicated that 10-5 M of 2,4-D was most effective for induction of rice callus. It has also been found that absence of 2,4-D increased callus re-formation in suspension culture, but no plant regeneration was observed. 6. By using 7% sucrose in differentiation medium, for all the three varieties, the plant regeneration frequency was raised up to 3 or 4 times than those of the 3% ones (Table 6). Occurrence of albino plants is often reported as one of the problems in rice anther culture. It is, however, no problem in seed-derived rice cell culture.

Key words: 2,4-D, yeast extract, cell suspension culture, plantlet regenration