The study of organization in plants has been stimulated in recent years primarily
as a result of refinements in the techniques of tissue and organ culture. It is now
well established that vegetative cells of higher plants can be grown in vitro and
propagated as relatively homogeneous, undifferentiated parenchyma or callus
tissue. Recent findings suggest that these cells, even though maintained in an
undifferentiated state for several years, still retain the potentiality for differentiation
of vascular tissue, roots, shoots, and even whole plants. The well-documented
studies of Skoog and Miller,' Steward and co-workers,2-4 Reinert,5 Halperin and
Wetherell,6 and others7 have demonstrated that mature diploid cells can be induced
to develop into plantlings representative of the species. One recognizes,
therefore, that totipotency may be inherent in any vegetative cell of the plant and
can be expressed to varying degrees when stimulated by the appropriate conditions
of nutrient culture.