The arbuscular mycorrhizal fungus Glomus mosseae gives contrary effects on phosphorus and arsenic acquisition by Medicago sativa

摘要

We used a compartmented pot cultivation system to investigate the role of the arbuscular mycorrhizal fungus (AMF) Glomus mosseae in phosphorus (P) and arsenic (As) acquisition by Medicago sativa, and mycorrhiza-mediated P-As interactions. Experimental results indicated that fungal colonization increased plant dry weight by a factor of around 6, and also substantially increased both plant P and As contents per plant. Irrespective of P and As addition levels, AM plants had shoot and root P concentrations 2 fold higher, but As concentrations significantly lower than corresponding uninoculated controls. The decreased shoot As concentrations were largely due to "dilution effects" that resulted from stimulated growth of AM plants and reduced As partitioning to shoots. The results provided further evidence for the protective effects of AMF on host plants against As contamination, and have uncovered key aspects of underlying mechanisms. The possible application of AMF in remediation practices is discussed.