The effect of nicotine and related compounds on germination and vacuolation in several species of rust uredospores

Abstract

Nicotine at 25 to 250 μl −1 stimulated germination of uredospores of Puccinia graminis var. tritici, P. punctiformis, P. coronata, Uromyces phaseoli, U. vignae , but not P. helianthi . Compounds related to nicotine, the 2-cyano, 3-cyano and 4-cyanopyridines, the 2-vinyl and 4-vinyl-pyridines, pyrrole and pyridine, induced different patterns of germination responses among the different rust species. Pyrrolidine was not stimulatory. At high concentrations, 500 and 1000 μl −1 , nicotine induced extensive vacuolation in uredospores of all species except P. punctiformis . Some of the compounds related to nicotine also induced vacuolation. The ability of a compound to induce germination was not always correlated with ability to induce vacuolation. Chemically induced vacuoles absorbed neutral red, indicating an active metabolic uptake of the dye.