Auxins include all those chemical substances which promote the growth of stems or coleoptiles sections and decapitated coleoptiles, but in same concentrations are incapable of causing the growth of a whole, undamaged plant. They occur naturally in the plant parts and are also chemically synthesized. The principal naturally occurring auxin is Indole-3-Acetic Acid (IAA) and Indole-3-Butyric Acid (IBA) is a synthetic auxin. Continue reading How do Auxins affect Plant growth?