Effect of 3% (w/v) of sucrose included in the freezing medium on freezing tolerance of rice suspension cells. Cell cultures (0.5 g cell inoculum in 50 mL medium) were incubated at 28°C for 7 days with or without 75 μM ABA. Harvested cells were frozen either in 0.1 mL of 3% sucrose or in 0.1 mL of sterile water. Freeze survival was determined by regrowth. Freeze survival of cell cultures (2.5 g cell inoculum in 1 L medium) incubated at 28°C with or without 75 μM ABA (no sucrose in the freezing medium) was also shown for comparison.