S. P. Humphreys, K. Oates, P. Ayres
Feb 1, 1991
Citations
0
Influential Citations
3
Citations
Quality indicators
Journal
Fungal Biology
Abstract
Systemic fungicides, e.g. triazoles, must be absorbed by a pathogen in order to be effective but, currently, neither amounts of fungicide in host cells and fungal hyphae at their interface, nor absorption by the pathogen in vivo , can be precisely determined. Using X-ray microanalysis (X-RMA) of planed frozen hydrated material in the scanning electron microscope, elements were quantified by ratioing against an Al standard. In wheat leaves infected by brown rust ( Puccinia recondita ), only small amounts of Cl were detected in untreated host and pathogen cells, but following treatment with a Cl-containing fungicide, diclobutrazol, increased amounts of Cl were found in mesophyll cells and, to a lesser extent, in intercellular fungal hyphae. In comparison, there was little, if any, accumulation of the mobile elements, K, P and S. The results demonstrate that X-RMA provides a new approach to the study of fungicide distribution within infected tissues. It is immediately useful for fungicides, such as diclobutrazol, containing elements found in only small amounts in host tissue but we suggest that, with full quantitation, X-RMA could be extended to other fungicides and could be used to measure their uptake by pathogens in vivo .