Showing papers by "Jacques Berthelin published in 1994"

Differential tolerance to Cd and Zn of arbuscular mycorrhizal (AM) fungal spores isolated from heavy metal-polluted and unpolluted soils

Abstract: Spores of arbuscular mycorrhizal fungi were isolated from two soils of field trials at INRA-Bordeaux (France) polluted by long-term application of a zinc-polluted sewage sludge (S2 soil) or treated with cadmium nitrate (Cd40 soil) and from corresponding unpolluted soils (F and Cd0 soils). These AM fungi were tested for their tolerance to Cd and Zn added as salt solutions with increasing concentrations (0 to 10 mg L−1) in a simple spore germination device. According to preliminary identification the predominant species in S2 and F cultures was Glomus mosseae, whereas Cd40 and Cd0 cultures contained a mixture of at least G. mosseae and G. etunicatum. Germination of Cd40 spores was more tolerant to Cd and Zn than for Cd0 spores, with EC50 values of 73 and 158 μmol L−1 added Cd and Zn corresponding to approximately 10 and 13 μmol L−1 remaining in solution in the device. The S2 spores from the sludge contaminated soil were more tolerant to Zn (EC50=87 μmol L−1), but not to Cd (EC50=7.5 μmol L−1), than the spores from the farmyard manure-treated F soil (EC50=38 and 8.8 μmol L−1, respectively). Thus, S2 culture exhibited a specific tolerance to Zn, which was lower than the unspecific tolerance of Cd40 culture to both Cd and Zn, despite the much higher Zn availability in S2 soil. These results indicate that AM fungi from different soils may differ in their metal susceptibility and that both metal specific and unspecific tolerance mechanisms may be selected in metal polluted soils.

Influence des métaux lourds sur la germination des spores de champignons endomycorhiziens à arbuscules dans les sols

Abstract: Summary A simple device (sandwich of spores in Petri dishes) was used to study the effect of soils with different heavy metal concentrations, and different origins of metals, on spore germination of Glomus mosseae and of two arbuscular-mycorrhizal fungal cultures isolated from polluted soils. Germination of G. mosseae spores was reduced to 4 % in the soil with the highest Cd, Zn and Pb concentrations. However, with still high cadmium concentrations varying from 1 to 100 mg/kg−1, the effect of metals was mitigated or increased depending on pH, phosphorus concentration and soil texture. In two soils containing 17 and 3 ppm Cd, metals did not affect the germination of G. mosseae spores due to their low availability. However, indigenous spores cultures from both soils were more tolerant to high cadmium concentrations than G. mosseae.