Maleic hydrazide-auxin interractions in water uptake of potato discs

Abstract

Using continuous incubation and pretreatment techniques, maleic hydrazide (MH) and naphthalene-acetic acid (NAA) were presented separately, successively, and in mixtures of varied concentration. With these experimental conditions, it was found that under conditions of continuous incubation MH can negate the stimulatory action of NAA on water uptake. The NAA apparently cannot overcome this inhibition. By pretreating the discs with NAA and then exposing them to MH the inhibitory action of the MH does not appear to be effective. Conversely, pretreating the discs with MH renders them insensitive to any subsequent stimulatory action of the NAA. An attempt was made to further investigate these phenomena. The results suggested that in this case the MH was acting on a process occurring during the early stages of auxin-induced cellular expansion.