Contribution of an arbuscular mycorrhizal fungus to the uptake of cadmium and nickel in bean and maize plants

Abstract

Two experiments were carded out in pots with three compartments, a central one for root and hyphal growth and two outer ones which were accessible only for hyphae of the arbuscular mycorrhizal fungus, Gloraus mosseae ([Nicol. and Gerd.] Gerdemann and Trappe). In the first experiment, mycorrhizal and nonmycorrhizal bean (Phaseolus vulgaris L.) plants were grown in two soils with high geogenic cadmium (Cd) or nickel (Ni) contents. In the second experiment, mycorrhizal and nonmycorrhizal maize (Zea mays L.) or bean plants were grown in a non-contaminated soil in the central compartment, and either the Cd-or Ni-rich soil in the outer compartments. In additional pots, mycorrhizal plants were grown without hyphal access to the outer compartments.Root and shoot dry weight was not influenced by mycorrhizal inoculation, but plant uptake of metals was significantly different between mycorrhizal and nonmycorrhizal plants. In the first experiment, the contribution of mycorrhizal fungi to plant uptake accounted for up to 37% of the total Cd uptake by bean plants, for up to 33% of the total copper (Cu) uptake and up to 44% of the total zinc (Zn) uptake. In contrast, Ni uptake in shoots and roots was not increased by mycorrhizal inoculation. In the second experiment, up to 24% of the total Cd uptake and also up to 24% of the total Cu uptake by bean could be attributed to mycorrhizal colonisation and delivery by hyphae from the outer compartments. In maize, the mycorrhizal colonisation and delivery by hyphae accounted for up to 41% of the total Cd uptake and 19% of the total Cu uptake. Again, mycorrhizal colonisation did not contribute to Ni uptake by bean or maize.The results demonstrate that the arbuscular mycorrhizal fungus contributed substantially not only to Cu and Zn uptake, but also to uptake of Cd (but not Ni) by plants from soils rich in these metal cations.

Determining uptake of radio‐labile soil cadmium by arbuscular mycorrhizal hyphae using isotopic dilution in a compartmented‐pot system

“…However, in the current investigation, the increased Cd concentrations in roots of mycorrhizal P. lanceolata plants are indicative of fungal immobilisation of Cd within the root/ fungal system. This is in agreement with other studies, which have shown preferential accumulation of Cd in root tissue (Dehn & Schüepp, 1989;Hetrick et al, 1994;Guo et al, 1996).…”

Mycorrhizal Fungi Increase Chromium Uptake by Sunflower Plants: Influence on Tissue Mineral Concentration, Growth, and Gas Exchange

“…[4] Mycorrhizal fungi have greatest impact on elements with narrow diffusion zones around plant roots, including heavy metals and phosporus (P). [5,6] Mycorrhiza enhance the uptake of Cu, [7] Zn, [5,8,9] nickel (Ni), [10] Cd, [11,12] Pb, [13] and other metals. [9] Mycorrhiza increase nutrient and water uptake, alleviate cultural and environmental stresses, and enhance disease resistance and plant health.…”

Heavy-Metal Stress and Developmental Patterns of Arbuscular Mycorrhizal Fungi

“…AM fungi are also involved in plant interactions with soil toxic metals, either by alleviating metal toxicity to the host or by accentuating it (for reviews, see references 9, 28, 32, and 34). The specific role of arbuscular mycorrhizae in the host exposure to metal stress and in the progression of the host stress response depends on a variety of factors, including the plant species (12) and ecotype (17); the fungal species (11) and ecotype (30); the metal (18) and its availability (15); soil edaphic conditions, including soil fertility (26); and plant growth conditions, such as light intensity (44) or root density (24). Despite the significant role that AM fungi play in plant interactions with soil toxic metals and the ubiquity of AM fungi in the soil environment, only recently has progress been made towards understanding the cellular mechanisms utilized by AM fungi to metabolize heavy metals and alleviate their cytotoxicity.…”