Chemical messengers that are produced in one part of an organism are hormones. Plant hormones differ from animal hormones because they don't maintain homeostasis and there are no endocrine organs that produce hormones. When plants respond to stimuli it's controlled by hormones. There are five major hormones: Auxin, Gibberellins, cytokinins, abscisic acid, and ethylene.
Auxin affects meristematic growth, cell elongation in shoots, cell division, growth of lateral buds, production of xylem, development of fruits, and can help produce ethylene. …
