How is Tissue Culture Done?
During this procedure, plant cells can be removed from various parts of a plant and placed on media in petri plates. The media does not contain the growth hormones normally present in a plant that tell the cells which tissue to develop into. As a result, the cells do not differentiate and instead form a mass of cells called a callus that are not differentiated into at the tissue level.
Since plant cells are totipotent, growth hormones can be added to the media triggering the callus cells to develop roots, shoots and eventually entire plants. Plants regenerated from tissue culture will be clones genetically identical to the cell they originated from. The only animal cells that have this totipotent characteristic are fertilized eggs.