Effects of mycorrhizal fungus isolates on mineral acquisition by Panicum virgatum in acidic soil

Plant ability to withstand acidic soil mineral deficiencies and toxicities can be enhanced by root-arbuscular mycorrhizal fungus (AMF) symbioses. The AMF benefits to plants may be attributed to enhanced plant acquisition of m ineral nutrients essential to plant growth and restricted acquisition of to xic elements. Switchgrass (Panicum virgatum L.) was grown in pH(Ca) (soil:1 0 mM CaCl2, 1:1) 4 and 5 soil (Typic Hapludult) inoculated with Glomus clar um, G. diaphanum, G, etunicatum, G, intraradices, Gigaspora albida, Gi. mar garita, Gi. rosea, and Acaulospora morrowiae to determine differences among AMF isolates for mineral acquisition. Shoots of mycorrhizal (AM) plants ha d 6.2-fold P concentration differences when grown in pH(Ca) 4 soil and 2.9- fold in pH(Ca) 5 soil. Acquisition trends for the other mineral nutrients e ssential for plant growth were similar for AM plants grown in pH(Ca) 4 and 5 soil, and differences among AMF isolates were generally higher for plants grown in pH(Ca) 4 than in pH(Ca) 5 soil. Both declines and increases in sh oot concentrations of N, S, K, Ca, Mg, Zn, Cu, and Mn relative to nonmycorr hizal (nonAM) plants were noted for many AM plants. Differences among AM pl ants for N and Mg concentrations were relatively small (< 2-fold) and were large (2- to 9-fold) for the other minerals. Shoot concentrations of minera l nutrients did not relate well to dry matter produced or to percentage roo t colonization. Except for Mn and one AMF isolate, shoot concentrations of Mn, Fe, B, and Al in AM plants were lower than in nonAM plants, and differe nces among AM plants for these minerals ranged from a low of 1.8-fold for F e to as high as 6.9-fold for Mn. Some AMF isolates were effective in overco ming acidic soil mineral deficiency and toxicity problems that commonly occ ur with plants grown in acidic soil.