plant hormone(redirected from Plant hormones)
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Related to Plant hormones: Plant growth regulators
plant hormoneany of several chemical substances produced in very low concentrations in plants, that control growth and development. They are now usually called growth substances. Plant HORMONES are produced in active MERISTEMS (e.g. root and shoot apices) from where they diffuse to other parts of the plant. A distinct contrast with animal hormonal systems is the fact that plants do not possess specific tissues for hormone production, nor a well-defined distribution system equivalent to the blood system.
Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005