Davies, Peter J. School of Integrative Plant Science, Cornell University, Ithaca, New York.
Last reviewed:April 2019
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- Nature, occurrence, and effects of hormones
- How plant hormones work
- Abscisic acid
- Salicylic acid
- Signal peptides
- Related Primary Literature
- Additional Reading
Any of a group of naturally occurring, organic substances that influence plant physiological processes at low concentrations. Plant hormones are chemical messengers synthesized within plants, where they help to regulate a variety of physiological processes (Fig. 1). The processes consist mainly of growth, differentiation, and development, although other processes, such as stomatal movement, may also be affected by plant hormones. Typical effective concentrations [in the range of 1 μM externally, or about 1–100 nM internally (about 1 part per billion), depending on the compound] are far below those where either nutrients or vitamins would be effective. See also: Hormone; Plant; Plant anatomy; Plant development; Plant growth; Plant physiology
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