16.2.5—Gibberellin role in stem elongation

Gibberellin can stimulate stem elongation by promoting cell expansion and, in some tissues, cell division. It changes the expression or activity of proteins that alter cell-wall properties and growth responses.

The hormone links developmental state to the mechanics of elongation. The response depends on concentration, tissue and interaction with other plant hormones.

A dwarf plant lacking sufficient gibberellin may regain stem elongation after treatment, but the response plateaus if another resource or pathway becomes limiting.

Gibberellin is not a universal ‘growth chemical’ that always increases every tissue’s size. Interpret the response in its developmental context.