How does indoleacetic acid change plant cell walls during cell elongation?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

fern life cycle — Plant development The life cycle of the fern. (1) Clusters (sori) of sporangia (spore cases) grow on the undersurface of mature fern leaves. (2) Released from its spore case, the haploid spore is carried to the ground, where it germinates into a tiny, usually heart-shaped, gametophyte (gamete-producing structure), anchored to the ground by rhizoids (rootlike projections). (3) Under moist conditions, mature sperm are released from the antheridia and swim to the egg-producing archegonia that have formed on the gametophyte's lower surface. (4) When fertilization occurs, a zygote forms and develops into an embryo within the archegonium. (5) The embryo eventually grows larger than the gametophyte and becomes a sporophyte.

Indoleacetic acid (IAA), the most important naturally occurring auxin, regulates plant cell elongation by acting on the chemical bonds of the carbohydrates that comprise plant cell walls.21

This hormonal action permits the cell walls to be irreversibly altered or deformed, a process that is accompanied by the entry of water into the cell and the synthesis of new cell wall material. While the precise mechanisms are still being studied, evidence suggests that auxins may influence this process by affecting protein synthesis, similar to how some animal hormones function. By modifying the cell wall structure, IAA enables the directional expansion necessary for plant growth and development.21