Systemic fungicides : apoplastic pathways to the fungus
Systemic fungicides : apoplastic pathways to the fungus
The effects upon Vicia faba's apoplastic system of two foliar pathogens (Uromyces fabae and Botrytis cinerea) were investigated in three ways.The diffusive resistance of the leaf surfaces was measured using a Lambda Ll-60 porometer. Botrytis infection initially caused a lowering of resistance but after eight days post-inoculation the resistance increased relative to control tissues. Modifications to the aperture of the porometer enabled lesion tissue to be measured independently. Results indicated that the lesion itself was responsible for the overall effects. A converse result was obtained with U.fabae infections. The resistance values fell markedly when the pustule erupted and the effects were proportional to disease intensity.The uptake of three free-space mobile chemicals was measured under similar conditions as the resistance determinations. Lead-EDTA and N-methyl pyridone accumulated in diseased tissues at levels proportional to the leaf resistance. Dimethirimol's accumulation pattern agreed with the respective resistance value for B.cinerea infections only. Dimethirimol's accumulation was restricted in U.fabae diseased tissues. In general the levels of accumulation were proportional to lesion cover, and the leaf surface inoculated.The localised accumulation around lesions was investigated quantitatively and uptake into U.fabae urediospores was measured. The distribution of these chemicals was illustrated by X-ray and autoradiographic techniques. Dimethirimol was shown to be largely confined to the veins whereas pyridoneand lead-EDTA were totally mobile. The geography of accumulation for each chemical was illustrated at different disease stages. A flushing technique was devised to measure the redistribution of chemical around the leaf under natural conditions. It was concluded that access to the fungus via the apoplast is impaired in the case of B.cinerea and relatively clear for U.fabae. These findings agreed in principle with those of other authors. The significance of these findings to systemic fungicide design is discussed.
University of Southampton
Wise, Christopher John Clayton
1977
Wise, Christopher John Clayton
Wise, Christopher John Clayton
(1977)
Systemic fungicides : apoplastic pathways to the fungus.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
The effects upon Vicia faba's apoplastic system of two foliar pathogens (Uromyces fabae and Botrytis cinerea) were investigated in three ways.The diffusive resistance of the leaf surfaces was measured using a Lambda Ll-60 porometer. Botrytis infection initially caused a lowering of resistance but after eight days post-inoculation the resistance increased relative to control tissues. Modifications to the aperture of the porometer enabled lesion tissue to be measured independently. Results indicated that the lesion itself was responsible for the overall effects. A converse result was obtained with U.fabae infections. The resistance values fell markedly when the pustule erupted and the effects were proportional to disease intensity.The uptake of three free-space mobile chemicals was measured under similar conditions as the resistance determinations. Lead-EDTA and N-methyl pyridone accumulated in diseased tissues at levels proportional to the leaf resistance. Dimethirimol's accumulation pattern agreed with the respective resistance value for B.cinerea infections only. Dimethirimol's accumulation was restricted in U.fabae diseased tissues. In general the levels of accumulation were proportional to lesion cover, and the leaf surface inoculated.The localised accumulation around lesions was investigated quantitatively and uptake into U.fabae urediospores was measured. The distribution of these chemicals was illustrated by X-ray and autoradiographic techniques. Dimethirimol was shown to be largely confined to the veins whereas pyridoneand lead-EDTA were totally mobile. The geography of accumulation for each chemical was illustrated at different disease stages. A flushing technique was devised to measure the redistribution of chemical around the leaf under natural conditions. It was concluded that access to the fungus via the apoplast is impaired in the case of B.cinerea and relatively clear for U.fabae. These findings agreed in principle with those of other authors. The significance of these findings to systemic fungicide design is discussed.
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Published date: 1977
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Local EPrints ID: 458657
URI: http://eprints.soton.ac.uk/id/eprint/458657
PURE UUID: 6d2a20e9-1156-41a8-82f2-be57f7c589f6
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Date deposited: 04 Jul 2022 16:53
Last modified: 04 Jul 2022 16:53
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Author:
Christopher John Clayton Wise
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