cytokinin

1. (biochemistry) Any of a class of plant hormones involved in cell growth and division.Examples: "The rate-limiting step for cytokinin biosynthesis involves a group of isopentenyltransferase (IPT) enzymes."; "SE onset depends on a complex network of interactions among plant growth regulators, mainly auxins and 'cytokinins, during the proembryogenic early stages, and ethylene and gibberellic and abscisic acids later in the development of somatic embryos."