Explanation

Auxins (from greek auxein : to grow) were first isolated from human urine. The terms ‘auxin’ is applied to the indole-3-acetic and (IAA) and to other natural and synthetic compounds having certain growth regulating properties. They are generally produced by the growing apices of the stems and roots, from where they migrate to the regions of their action. Auxins, like IAA and Indole Butyric Acid (IBA) have been isolated from plants. NAA (naphthalene acetic acid) and 2, 4-D (2, 4-dichlorophenoxyacetic) are synthetic auxins. All these auxins have been used extensively in agriculture and horticultural practices