Organic compounds found in plant sprouts. They promote tissue growth through cell elongation rather than multiplication. ... (12 Dec 1998) ... 
(Green plants as organisms) plant hormones that trigger growth
A group of plant growth substances (often called phytohormones or plant hormones), the most common example being indole acetic acid (IAA), responsible for raising the pH around cells, making the cell wall less rigid and allowing elongation.
Type: Term Pronunciation: auk′sinz Definitions: 1. A type of plant hormone.
These are plant hormones which control many aspects of plant growth.
A group of hormones involved in controlling plant growth and other functions; once thought responsible for phototropism by causing the cells on the shaded side of a plant to elongate, thereby causing the plant to bend toward the light.