Isolation of Single Cells -
Single cells can be isolated either from cultured tissues or from impact plant organs, the former being more convenient than the latter. When isolated from cultured tissue, the latter is obtained by culturing an organised tissue (explant) into callus (callus is undifferentiated growth in solid form).

The callus may be separated from explant and transferred to fresh medium to get more tissue. Pieces of undifferentiated calli are transferred to liquid medium, which is continuously agitated to obtain a 'suspension culture'. Agitation of pieces breaks them into smaller c1umps and single cells, and also maintains uniform distribution of cells and cell clumps in the medium. It also allows gaseous exchange.