Flotation

Protoplasts being lighter (low density) then other cell debris, gradients may be used, which will allow the protoplasts to float and the cell debris to sediment.

A concentrated solution of mannitol, Sorbitol and sucrose (0.3-0.6M) can be used as a gradient and crude protoplasts suspension may be centrifuged in this gradient at an appropriate speed. Protoplasts can be pipetted off from the top of the tube after centrifugation.

This method causes little loss or damage relative to that in the ‘sedimentation and washing’ method. Babcock bottle shown in also used by some workers for flotation, since it facilitates removal of protoplasts.

Flotation of the protoplasts in a Babcock bottle greatly eases the removal of purified protoplasts from the sucrose cushion