Ethylene-induced growth and proton excretion in the aquatic plant Nymphoides peltata.

In the presence of auxin, ethylene can promote growth in petioles of N. peltata (S.G. Gmel.) O. Kuntze. Acid buffer will also stimulate growth in the tissue and, in abraded petiole segments, ethylene-stimulated growth is accompanied by a marked acidification of the medium. Auxin stimulates growth in this tissue and, for various auxin and ethylene treatments, the amount of growth is closely correlated with the degree of medium acidification. The results are consistent with predictions of the 'acid-growth' theory, and provide the first evidence that ethylene acts by an 'acid-growth' mechanism.