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

Abstract

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 of 7Be, 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 of 22Na, 65Zn , 75Se, 83Rb, 85Sr, and 88Y 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 of 7Be, 46Sc, 51Cr, 54Mn, 59Fe, 56Co, and 88Zr 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.