Cytokinins in regulation of plant growth.

Abstract

The extension of principles governing gene-controlled protein biosynthesis in prokaryotes as a basic regulatory mechanism common to all growth and developmental processes in eukaryotes, also, is now generally accepted. The question, then, is, what factors are involved in modulating the expression of genetic potentials in cells with an identical genome so as to permit development of functional, multicellular organisms? In the case of plants, it is clear that environmental factors, temperature, light, and inorganic nutrients influence differentiation and development in striking, specific ways, but, as in animals, it is recognized that endogenous growth factors, or hormones, mediate these effects and more generally serve to regulate the expression of genetic potentials. Furthermore, in plants as in animals, several categories of such substances exist, and changing balances in activity between them may modulate metabolism and bring about morphogenesis and functional changes characteristic of normal ontogeny. In this context, I wish to discuss the group of substances referred to as cytokinins.