吲哚乙酸（Indole-3-acetic acid，IAA）是自然界中最广泛存在的生长素之一,又称为吲哚-3-乙酸，属于吲哚类化合物，是一种植物内源生长素，激活了特定植物细胞相应的通路，调节了植物生长，被命名为生长素，广泛分布于多种植物体内。此外，生长素（Auxin）是最早被发现的植物激素，其化学本质是吲哚乙酸，因而习惯上常把吲哚乙酸作为生长素的同义词。在植物的生长发育过程中具有极为重要的调节作用

Indole-3-acetic acid (IAA) is one of the most widely existing auxin in nature, which is also known as indole-3-acetic acid. As an indole-class compound, it is an endogenous auxin that activates corresponding pathways of specific plant cells and regulates plant growth. It is named auxin. It is widely distributed in many plants. In addition, Auxin is the earliest discovered plant hormone, and its chemical nature is indoleacetic acid, so indoleacetic acid is often used as a synonym for Auxin. It plays an important role in the regulation of plant growth and development