Culture of rice protoplasts with oxygenated pe- rfluorodecalin in glass bottles resulted in a 5-fold increase in mean plating efficiency, as assessed optically after 35 d, compared to untreated con- trols (P < 0.01) coupled with a 12”/0 increase (P < 0.01) in plant regeneration (Table 1). The mean number of shoots regenerating from each protoplast-derived colony after 63 d in response to culture with oxygenated perfluorodecalin (n = 40) was also increased from 4 + 1 to 8 _t 1 (P < 0.05: Table 1). A 7.5-fold increase (P < 0.01) in the mean plating efficiency of protoplasts cultured with oxygenated perfluorodecalin in the 24-well culture dishes was also observed (Table 2) showing that this novel cultural ap- proach could be readily extended to small-vol- ume systems. Image analysis assessments revealed a signifi- cant increase (P < 0.01) in protoplast-derived colony growth following culture with PFC. For example, the mean area of the culture plates covered by colonies after 35 d (n = 4) was increased from 11.6% + 5.8% in controls to 49.8% ? 5.4% (P < 0.01) in response to me- dia supplementation with oxygenated pe- rfluorodecalin (Table 2). In contrast, visual assessments revealed a 7.5-fold increase in plat- ing efficiency over the same time period. The ploidy of the protoplast-derived plants transferred to the glasshouse, as assessed by flow cytometry, was unaffected by culture of protoplasts with oxygenated perfluorodecalin. Thirty plants derived from protoplasts cultur- ed in the presence of perfluorodecalin and the same number of plants regenerated from proto- plasts cultured in the absence of this com- pound were all diploid. Plants regenerated from protoplasts exposed to oxygenated perfluorode- calin flowered 1 lo&200 d after their transfer to the glasshouse and showed no marked differ- ences in morphology or pollen viability com- pared to plants derived from protoplasts cultured in the absence of perlluorodecalin (Tab- le 3) or seed-derived individuals (Davey et al., 1991).