Biological and Biochemical Effects of Cytokinin-active Phenylurea Derivatives in Tissue Culture Systems

Abstract Plant growth regulator studies and plant tissue culture research have been closely related and mutually supportive. The manipulation of plant cells, tissues, and organs in culture, with important applications in propagation and genetic modification of plants, is highly dependent on the use of appropriate growth regulator regimes. Conversely, tissue culture systems are useful as bioassays to define the growth-regulating activity of many compounds. The discovery of the cytokinin N -(2-furanylmethyl)-1 H -purin-6-amine (kinetin) by Miller et al. (17) was particularly relevant in this respect. Whereas the testing of this cytokinin and its structural analogues for biological activity was dependent on callus culture bioassays, the subsequent availability of synthetic cytokinins created many new opportunities in the field of plant tissue culture.