Sedimented protoplasts were suspended in 1 ml of a solution of35% (w/v) polyetylene glycol (PEG. MW. 6,000) and 0.05 M CaC12.2H20 in 0.05 M glycine NaOH buffer pH 7.5. After incubation at 25C for 10 min, the suspension was centrifuged at 700 g for 5
min.