Callus Culture
Callus is basically a more or less non-organized
tumor tissue which usually arises on wounds of
differentiated tissues and organs. Thus, in
principle, it is a non-organized and little-
differentiated tissue. The cells in callus are of a
parenchymatous nature. When critically
examined, callus culture is not homogeneous
mass of cells, because it is usually made up of
two types of tissue: differentiated and non-
differentiated. Explant tissue is a differentiated
tissue (roots, stem, leaves, flowers, etc.) which
is used as a starting material for callus induction.
These explant tissues generally show distinct
planes of cell division, cell proliferation and
organization into specialized structures such as
vascular systems. If there are only differentiated
cells present in an isolated explant, then
dedifferentiation must take place before cell
division can occur. Parenchyma cells present in
the explant usually undergo this differentiation.
If the explant already contains ...