Detection of heavy metals in oak mycorrhizae of northeastern Pennsylvania forests, using x-ray microanalysis

Abstract

1987. Detection of heavy metals in oak mycorrhizae of northeastern Pennsylvania forests, using x-ray microanalysis. Can. J. Bot. 65: 2622-2627. A survey of red and white oak mycorrhizae, using semi-quantitative x-ray microanalysis, has shown a significant difference in heavy-metal deposition between the forest-grown oaks on acidic (mor) and neutral (mull) soils. There are significantly higher levels of nickel, iron, aluminum, and copper within oak roots of Pocono (mor) forests than of Lehigh Valley (mull) forests. The Pocono oak roots were taken from acidic soils derived from sandstone, shales, and conglomerate parent rock materials, while Lehigh Valley oak roots were removed from neutral soils derived from carbonate-rich limestone and dolomite. Chemical analysis of these soils demonstrated higher plant-available heavy-metal content in the acidic soils. Digital line profiles indicated that heavy metals, especially nickel and iron, were concentrated in the peripheral mycorrhizal mantle region of cross-sectioned roots. Since nickel and other heavy metals are known to be toxic to fungi and plant tissues, the high concentrations of metals may be responsible for the decreased frequencies of advantageous ectomycorrhizal associations in oaks growing under certain acid-stressed conditions. WASSERMAN, J. L., MINEO, L., MAJUMDAR, S. K., et VAN TYNE, C. 1987. Detection of heavy metals in oak mycorrhizae of northeastern Pennsylvania forests, using x-ray microanalysis. Can. J. Bot. 65 : 2622-2627. A I'aide d'une mCthode semi-quantitative de microanalyse aux rayons-X, les auteurs ont observe, chez les mycorhizes des chknes rouge et blanc, une difference significative dans la dCposition de mCtaux lourds selon que les chknes ont poussC sur des sols acides (mor) ou neutres (mull). On retrouve significativement plus de nickel, de fer, d'aluminium et de cuivre chez les chknes blancs provenant des forkts de Pocono (mor) que ceux provenant des for& de Lehigh Valley (mull). Les racines de chgne venant de Pocono ont Ct C prelevCes sur des sols acides dCrivCs d'une roche-mkre comportant du grks, des schistes et du conglomCrat alors que les racines de chkne venant de Lehigh Valley ont Ct C prClevCes sur des sols neutres dCrivCs d'une rochemkre contenant de la pierre-i-chaux riche en carbonates et de la dolomie. A I'analyse chimique, ces sols acides rtvklent des teneurs plus ClevCes en mCtaux lourds accessibles aux plantes. Les profils d'analyse digitale montrent une plus grande accunlulatin des mCtaux lourds, particulikrement le nickel et le fer, dans la region pCriphCrique du manteau des mycorhizes observCes en coupes transversales. Puisqu'on connait I'effet toxique du nickel et des autres mCtaux lourds sur les champignons et les tissus vCgCtaux, il se pourrait que ces fortes concentrations et les tissus vCgCtaux, il se pourrait que ces fortes concentrations en mCtaux soient responsables pour la diminution de frkquence des associations ectomycorhiziennes avantageuses chez les chknes poussant dans certains sols acides.[Traduit par la ...

Changes in soil solution Zn and pH and uptake of Zn by arbuscular mycorrhizal red clover in Zn-contaminated soil

“…The binding capacity of fungal hyphae to metals has been proposed as the mechanism responsible for tolerance to heavy metals in ericaceous mycorrhiza and ectomycorrhizal plants (Bradley et al, 1981;Brown and Wilkins, 1985;Wasserman et al, 1987;Chen et al, this issue). Chen et al (this issue) grew two AM fungi, G. mosseae and G. versiforme, in a glass bead compartment cultivation system with maize and red clover as host plants.…”

Effectiveness of autochthonous bacterium and mycorrhizal fungus on Trifolium growth, symbiotic development and soil enzymatic activities in Zn contaminated soil

“…Fungal hyphae of selected AM inocula may have the capacity to bind metals present in roots or in the rhizosphere and this activity would decrease metal translocation from the root to the shoot, which Wasserman et al (1987) proposed as mechanisms for enhancing plant tolerance. The bacterial ability for metal sequestration has also been observed (Vivas et al 2005).…”

Arbuscular mycorrhiza can depress translocation of zinc to shoots of host plants in soils moderately polluted with zinc

“…The underlying mechanism is thought to be the binding capacity of fungal hyphae to metals in the roots or in the rhizosphere which immobilizes the metals in or near the roots and thus depresses their translocation to the shoots (Bradley et al, 1981;Brown and Wilkins, 1985;Wasserman et al, 1987). However, no firm con-clusions have been drawn concerning the role of AM fungi in plant uptake of trace metals (Zhu et al, 2001).…”