Plant hormones act by directly affecting the activities of signal transduction pathways.
Signal transduction pathways are involved in the transfer of signals from outside of the cell to the inside of the cell for the regulation of various cellular activities. For this, the extracellular signalling molecules bind to the receptors that are located on the cell membrane. After their binding due to some change in the receptor molecule, a signal is triggered in to the cell and thus information from outside of the cell is transferred to the inside of the cell through these transduction pathways.
Plant hormones affect these pathways and as a result membranes, enzymes, and genes are also influenced by the plant hormones.
