ABSTRACT
Differentiation of a cell has been of considerable interest, but its understanding is far from complete. The significance of cell differentiation lies in the fact that during the development of a multicellular organism, information from a variety of sources, genetic and otherwise, interacts and influences the expression of certain cells so that they become specialized to perform particular functions. A neoplastic cell is capable of continuous proliferation on a hormone-free medium. Neoplastic cells are a parallel plant system for the study of tumor biology. Plant cells on prolonged culture, either on agar or liquid medium, reveal changes in their physiological potentialities, particularly in respect of hormone requirements. At times, they become hormone autonomous and this change has been described as cell habituation. Habituation has also been reported in respect to cytokinin requirement and is of more frequent occurrence than auxin habituation. The first recorded physiological change was in respect of auxin requirement.
