Physiology. Any of various substances that act synergistically with substances which promote cell division. Cf. auxetic, adj. 2. Obsolete.

any substance required by an organism in minute amounts in order to maintain its growth.

any of various water-soluble substances identified as being essential for the growth of some organism; spec. pantothenic acid.

an organic substance, such as a hormone, vitamin, or auxin, which regulates growth.

A chemical agent which is or may be capable of bringing about or determining morphogenesis.

Plant Physiology. = cytokinin, n.

A photo-oxidation product, C15H22O3, of violaxanthin that occurs in certain plant tissues as a growth inhibitor.