The fungitoxicity of metal ions

Abstract

The in oitro fungistatic activity of some twenty-four metal cations has been determined against Alternaria tenuis and Botrytis fubae. The metal salts, mainly nitrates, were tested in aqueous solution without added spore germination stimulant. The logarithm of the metal ion concentration at the E D 50 value has been found to conform to the exponential relationship with electronegativity proposed by Danielli & Davies (1951). These results are discussed in relation to the site of action of metal cations on the fungal cell. I N T R O D U C T I O NThe concept of a general relation between metal ion toxicity and some physical or chemical property of the metal has held interest since the beginning of this century. Mathews (1904) considered the toxicity of metal ions to eggs of the fish Fundulus heteroclitus to be related to the ease with which the ions gained or lost electric charges and hence to the electrode potential of the metal. Later work by Jones (1939, 1940) has shown that for a given degree of toxic action on the stickleback, Gasterosteus aculeatus, and the planarian, Polycelis nigra, the logarithm of the toxic concentration of some eighteen metal ions is a linear function of the standard electrode potential.

Response of ectomycorrhizalPinus banksiana andPicea glauca to heavy metals in soil

“…The precise mechanism of ectomycorrhizal inhibition is unknown. Heavy metal concentrations utilized in this study are known to be fungitoxic (Ashida, 1965;Ross, 1982;Somers, 1961). Gildon tomycorrhizal seedlings supports each of these hypotheses.…”

The influence of heavy metals on carbon dioxide evolution from a typic xerochrept soil

“…For each of the tested rates of loading, the percentages of inhibition at the end of incubation, as well as C20, C50, EC2o, EC5o and ECs0/EC20 ratios, were correlated with electronegativity (Jenkins and Gareth win Jones, 1980), ionic potential (Huheey, 1972) and subsequently with softness (Misono et al, 1967), a parameter derived from the theory of Pearson (1963) on soft acids and bases, which describes numerically the tendency of a metal to form covalent bonds. Somers (1961) suggested that the depressive effect of metals is related to their strength of covalent binding to surface ionic groups, situated outside or on the membrane of microorganisms. In this study, little agreement was found between observed toxicity sequences of metals and metal sequences based on softness.…”

Interactions of fungi with toxic metals

“…This is because metal toxicity has been, and remains the basis of many fungicidal preparations used in the control of plant pathogens and to preserve natural and synthetic materials (Horsfall, 1956;Ross, 1975). Early work often had a phytopathological perspective with many studies relating to assessment of toxicity (Somers, 1961). Subsequent observations on the ability of fungi to resist and adapt to toxic metals stimulated further work on the physiological, biochemical and genetical explanations for these phenomena (Ashida, 1965;Ross, 1975;Gadd 1986a).…”