Figure 4. Effect of heat shock treatment on transfection efficiency.

Oil palm protoplasts were incubated at 45°C for 5 min and then on ice for 1 min before mixing with 50 µg of CFDV-hrGFP plasmid DNA and then PEG-MgCl₂ solution (25% PEG, 50 mM MgCl₂, 3% KCl and 3.6% mannitol, pH 6.0). The protoplasts were incubated at 26°C for 3 days (A), 6 days (B) and 9 days (C). Red arrows indicate protoplasts showing GFP fluorescence. The transfection efficiencies represent the mean of three replicates. Scale bar  = 100 µm in (A), 10 µm in (B) and (C).