Plant hormones that, among other functions, regulate the growth of grass (after that gibberellin is activated by an enzyme). In 1 996, Lew Mander and Richard Pharis discovered an analogue (i.e., a chemical that is similar) to grass gibberellin that does not cause grass to grow. When this analogue is sprayed onto grass, it mixes into the naturally occurring grass gibberellin and significantly slows grass growth (thus reducing the amount of mowing required for lawns, golf courses, etc.).
This sentence describes a group of chemical compounds that share similarities with gibberellic acid in terms of their biological properties and structural composition, specifically the presence of a gibbane ring framework.