Arbuscular mycorrhizal fungi influence the accumulation and partitioning of Cd and P in bashfulgrass (Mimosa pudica L.) grown on a moderately Cd-contaminated soil

The presence of heavy metals (HMs) at high concentrations is one of the major issues encountered with the direct usage of medicinal plants (MPs). Although arbuscular mycorrhizal (AM) fungal inoculations have been suggested for safe crop productions on HM-contaminated soils, the variations in both plant and fungal capabilities may contribute to differing outcomes of symbioses involving different combinations of the two. Therefore, a 14-week pot experiment was conducted to investigate cadmium (Cd) and phosphorus (P) acquisitions by bashfulgrass (Mimosa pudica L) from a Cd-contaminated (1.6 mg kg(-1)) soil in response to inoculations of two different AM fungal species, Glomus caledonium (Cc) and Glomus versiforme (Gv). Root mycorrhizal colonization, shoot and root biomasses, and Cd and P concentrations of bashfulgrass, as well as soil pH, acid phosphatase activity, and available Cd and P concentrations, were determined. Compared with the non-inoculated control, both Cc and Gv inoculations significantly increased (P<0.05) root mycorrhizal colonization rates and soil acid phosphatase activities. However, only Cc inoculation significantly increased (P<0.05) soil available P concentration, plant P acquisition and shoot biomass of bashfulgrass, while Gv inoculation significantly decreased (P<0.05) P translocation efficiency and increased (P<0.05) root P concentration. In addition, both Cc and Gv inoculations had no significant effects on plant Cd translocation efficiencies, but significantly elevated (P<0.05) soil pH and decreased (P<0.05) soil DTPA-extractable (phytoavailable) Cd concentrations, plant Cd acquisitions and tissue Cd concentrations of bashfulgrass. The results indicated differential responses of bashfulgrass in accumulations and translocations of Cd and P according to different AM fungal species, and demonstrated the potential application of AM fungi in the production of MPs on Cd-contaminated soils. (C) 2013 Elsevier B.V. All rights reserved.