Transport of Trace Elements through the Hyphae of an Arbuscular Mycorrhizal Fungus into Marigold Determined by the Multitracer Technique

The contribution of the hyphae of an arbuscular mycorrhizal (AM) fungus to the uptake of traceelements by marigold (Tagetes patula L.) was studied using a multitracer consisting of radionuclides of⁷Be,²²Na,⁴⁶Sc,⁵¹Cr,⁵⁴Mn,⁵⁹Fe,⁵⁶Co,⁶⁵Zn,⁷⁵Se,⁸³Rb,⁸⁵Sr,⁸⁸Y,⁸⁸Zr, and^95mTc. Marigold plants colonized and not colonized with Glomus etunicatum were grown for 40 and 60 d in pots with a hyphal compartment separated from the rooting medium by a fine nylon mesh. The multitracer was applied to the hyphal compartment. We found that the uptake of²²Na,⁶⁵Zn,⁷⁵Se,⁸³Rb,⁸⁵Sr, and⁸⁸Y by the mycorrhizal plants was higher than that by the non-mycorrhizal ones. In the case of^95mTc, the uptake by the mycorrhizal plants was similar to that by the control ones. The radioactivity of⁷Be,⁴⁶Sc,⁵¹Cr,⁵⁴Mn,⁵⁹Fe,⁵⁶Co, and⁸⁸Zr could not be detected in any plants. Our results suggest that the AM fungus can absorb Na, Zn, Se, Rh, Sr, and Y from the soil and transport these elements to the plant through its hyphae. The transport ability of the AM fungal hyphae to plant for Be, Sc, Cr, Mn, Fe, Co, Zr, and Tc is likely to be low.