Stressed Out Over a Stress Hormone

摘要

When stresses mount, plants can't simply walk away from their problems or head to the nearest bar. Instead of turning to a stiff drink, plants can count on a chemical called abscisic acid (ABA) to bail them out. Discovered in the 1960s by groups searching for substances that regulate bud dormancy and the shedding of leaves and fruits, ABA has turned out to be a vital hormone that plants use when conditions are rough. Concentrations of ABA in leaves shoot up when plants dry out or get too cold; and as the hormone spreads throughout the plant, it stimulates genes involved in a variety of responses. The hormone curtails water loss, helps seeds wait out bad conditions, and inhibits root and other vegetative growth.