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FUNGICIDAL ACTIVITY AND CHEMICAL CONSTITUTION
Author(s) -
BYRDE R. J. W.,
CLIFFORD D. R.,
WOODCOCK D.
Publication year - 1958
Publication title -
annals of applied biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 80
eISSN - 1744-7348
pISSN - 0003-4746
DOI - 10.1111/j.1744-7348.1958.tb02193.x
Subject(s) - mycelium , chelation , fungicide , spore , biology , alkyl , spore germination , nuclear chemistry , medicinal chemistry , botany , organic chemistry , chemistry
A series of 5‐ n ‐alkyl oxines was tested against the mycelium of Aspergillus niger. As non‐chelated molecules, they showed maximum fungistatic activity at a chain length of 5–6 carbon atoms. Values of Ferguson's thermodynamic activity coefficient, obtained from spore germination tests with Sclerotinia laxa , indicated that the mechanism of toxicity of the lower homologues is predominantly chemical, whilst that of the n ‐amyl and higher members is mainly physical. The ED 50 value of 5‐ n ‐amyl‐6‐hydroxyquinoline, which is incapable of chelation, was found to be eighty times greater than that of 5‐ n ‐amyl oxine (in the non‐chelated form). The optimum initial pH for fungistatic activity of the latter was 5.4–5.6. In the presence of metals the pattern of fungistatic activity was markedly altered: maximum activity in the presence of Cu 2+ , Fe 2+ and Zn 2+ was found with oxine and 5‐methyloxine.