Short-term effects of Mn2+ on elongation growth and H+ -extrusion in Zea mays L. coleoptile segments

Abstract

The effect of 10<sup>-2</sup>-10<sup>-6</sup> M Mn<sup>+2</sup> on the growth and acidification of the incubation medium by <em>Zea mays</em> L. coleoptile segments was studied. It is shown that 10<sup>-5</sup>M manganese stimulated growth (in comparison to a control without Mn<sup>+2</sup>) while concentrations from 10<sup>-2</sup> to 10<sup>-4</sup>M clearly inhibited it. It was also found that manganese at the studied concentration range significantly inhibited acidification of the incubation medium. Auxin, at a concentration of 10<sup>-5</sup>M, reversed the inhibitory effect of Mn<sup>+2</sup> (with the exception of 10<sup>-2</sup>M) on the growth and acidification of the incubation medium by <em>Zea mays</em> L. coleoptile segments.