Plants also communicate with each other so that they can coordinate with each other in response to change in light, dark and temperature. All these changes play an important role for plants as they guide and control the growth, flowering and fruiting for them. Plants extensively use nitric oxide and calcium for plant cell signaling. Most of the signaling is done through cell surface receptors. These cell surface receptors are enzyme linked receptors. For cell surface signaling plants extensively depends upon the transmembrane receptor i.e. serine/threonine kinases. For this kind of receptor based signaling plants have a typical extracellular ligand binding domain and a cytoplasmic domain. The most abundant of such a type is Leucine Rich Repeat(LRR) proteins which leucine rich repeats in them.
Plant growth regulators also known as plant hormones are responsible for the plant development by coordinating them . Plant hormones like ethylene, auxin, gibberellins, cytokinins and abscisic acid. They can be transported locally or they diffuse into cell walls.