Water transport in maize roots under the influence of mercuric chloride and water stress: A role of water channels

Abstract

The influence of inhibitor of water channels, HgCl2, on water diffusion in maize (Zea mays L.) seedling roots was investigated with the pulsed nuclear magnetic resonance (NMR) method. Blocking of water channels decreased the water permeability of cell membranes by 1.5 - 2 times. This effect of HgCl2 was exhibited only in the roots of seedlings grown in a nutrient solution containing Ca2+ and was reversed with Hg-scavenging agent β-mercaptoethanol. Subsequent incubation of Ca2+- deficient roots in the nutrient solution with Ca2+ recovered the sensitivity to HgCl2. The water stress decreased water diffusion rates similarly to HgCl2 and the effects of water stress and HgCl2 were not additive. The obtained data demonstrate the possibilities of the pulsed NMR method for study of the transmembrane water exchange in vivo in connection with water channel functioning.