What is the role of auxin in plants?

Auxin is a key plant hormone primarily known for its role in promoting cell elongation and influencing various growth processes. It achieves this by facilitating the loosening of cell walls, allowing for increased expansion of cells, particularly in regions of active growth such as apical meristems. Auxin is important in processes like phototropism and gravitropism, where it helps the plant grow towards light or in response to gravity by redistributing itself within the plant. This redistribution causes differential growth rates, which can bend the plant towards the light source or cause roots to grow downward.

Additionally, auxin plays a vital role in various developmental processes including root development, flowering, and apical dominance, where it inhibits the growth of lateral buds and promotes the growth of the main stem. Understanding the multifaceted role of auxin highlights its significance in plant biology and development.

The other options do not encompass the primary function of auxin. For example, while auxin has some influence on sugar transport, it is not primarily responsible for regulating this process. Similarly, auxin does not inhibit cell elongation; rather, it promotes it. While there are mechanisms by which plants can protect themselves from herbivores through various chemicals and defenses, auxin itself is not