Modyfikacja właściwości powierzchniowych bakterii glebowych w obecności wybranych preparatów grzybobójczych

Abstract

The intensification of agriculture has increased the use of fungicides in plant production. Plant protection products can change the local environ- mental conditions in the soil, as they get leached from the surface of plants. Among the many studies conducted over the fungicides, their impact on soil microflora should be analysed. In this study the effect of two fungicides: Acrobat MZ 69 WG (active substances: dimethomorph 90 g kg-1, mancozeb 600 g kg-1) and Gwarant 500 SC (active substance: chlorothalonil 500 g kg-1) on the modification of surface properties of soil microorgan- isms Rahnella aquatilis and Raoultella planticola were tested. The re- sults showed that both Acrobat MZ 69 WG and Gwarant 500 SC modi- fied the surface of cells of R. aquatilis and R. planticola towards more hydrophobic properties. Furthermore, the addition of Acrobat MZ 69 WG increased the cell inner membrane permeability of the selected strains of soil, which is not observed in the case of the Gwarant 500 SC. The concentration increase of the two fungicides reduced the zeta potential of the strain of R. planticola down to a minimum value of -26.2 mV (in the presence Gwarant 500 SC) and the increase – strain of R. aquatilis (up to 16.9 mV in the presence Acrobat MZ 69 WG). The results show a signifi- cant modifications of the cell surface of soil bacteria under the influence of tested fungicides. The direction and intensity of the changes depended on the type and dose of the fungicide. Simultaneously, statistical analysis did not indicate direct correlation between changes of the fungicides con- centration and all analysed cell surface properties. The study illustrates the surface modification of bacterial cells in the presence of the fungicides.