A phytohormone is a vegetable Hormone Plante S. It is a substance chemical organics which controls the vegetable Croissance or which intervenes in the communications between different vegetable individuals (a stressed tree can emit a hormone informing of other trees that a cause of stress is present. This stimulus can increase the production of tannins or defensive molecules of the receiving plant. One speaks sometimes about hormones of stress to describe the molecules emitted by plants in a state of lack of water or wounded, which can attract the predatory ones, but also the predatory ones of these predatory.

To be a phytohormone, a substance must be:

• endogenous (i.e. not provided by the medium)
• oligodynamic (and to act with low dose, about the micromole)
• vectrice of information (brought to a target cell selectively sensitive to its action and of which it influences operation).

These are the requirements which make it possible to make the distinction between a phytohormone and a trophic substance.

See too

• the paragraph '' vegetable hormone '' of the article Hormone
• vegetable Hormone Category