Biphasic effect of abscisic acid on plants: an hormetic viewpoint

Abscisic acid (ABA) is a major phytohormone that regulates development and growth. Increasingly, the literature indicates that ABA enhances and inhibits a spectrum of plant responses within an hormetic-like biphasic dose–response manner. A recent extensive study on the response of a variety of Arabidopsis lines to ABA suggested the widespread occurrence of hormetic dose responses. Our independent reassessment of these data reveals the occurrence of more than 30 hormetic dose–response relationships with quantitative features fully consistent with the substantial and extensively assessed literature on plant hormesis. This analysis significantly extends earlier findings indicating that ABA mediates a broad spectrum of hormetic dose responses in plants. ABA-induced hormesis provides a novel framework for research with the potential to advance the current scientific bases of plant ecology, physiology, and toxicology and to enhance agricultural yields and productivity.