Arbuscular mycorrhiza enhanced arsenic resistance of both white clover ( Trifolium repens Linn.) and ryegrass ( Lolium perenne L.) plants in an arsenic-contaminated soil

In a compartmented cultivation system, white clover ( Trifolium repens Linn.) and ryegrass ( Lolium perenne L.), with their roots freely intermingled, or separated by 37 μm nylon mesh or plastic board, were grown together in an arsenic (As) contaminated soil. The influence of AM inoculation on plant growth, As uptake, phosphorus (P) nutrition, and plant competitions were investigated. Results showed that both plant species highly depended on mycorrhizas for surviving the As contamination. Mycorrhizal inoculation substantially improved plant P nutrition, and in contrast markedly decreased root to shoot As translocation and shoot As concentrations. It also showed that mycorrhizas affected the competition between the two co-existing plant species, preferentially benefiting the clover plants in term of nutrient acquisition and biomass production. Based on the present study, the role of AM fungi in plant adaptation to As contamination, and their potential use for ecological restoration of As contaminated soils are discussed. Both white clover and ryegrass highly depend on the mycorrhizal associations for surviving heavy arsenic contamination.