Arsenic (As) contamination of irrigation water represents a major constraint to Bangladesh agriculture. While arbuscular mycorrhizal (AM) fungi have their most significant effect on P uptake, they have also been shown to alleviate metal toxicity to the host plant. This study examined the effects of As and inoculation with an AM fungus, Glomus mosseae, on lentil (Lens culinaris L. cv. Titore). Plants were grown with and without AM inoculum for 9 weeks in a sand and terra green mixture 50:50 v/v and watered with five levels of As (0, 1, 2, 5, 10 mg As L )1 arsenate). Inoculum of Rhizobium leguminosarum b.v. Viceae strain 3841 was applied to all plants. Plants were fed with modified Hoagland solution (1/10 N of a full-strength solution and without P). Plant height, leaf number, pod number, plant biomass and shoot and root P concentration/offtake increased significantly due to mycorrhizal infection. Plant height, leaf/ pod number, plant biomass, root length, shoot P concentration/offtake, root P offtake and mycorrhizal infection decreased significantly with increasing As concentration. However, mycorrhizal inoculation reduced As concentration in roots and shoots. This study shows that growing lentil with compatible AM inoculum can minimise As toxicity and increase growth and P uptake.

Arsenic (As)-contaminated irrigation water is responsible for high As levels in soils and crops in many parts of the world, particularly in the Bengal Delta, Bangladesh and West Bengal, India. While arbuscular mycorrhizal (AM) fungi markedly improve phosphorus (P) uptake, they can also alleviate metal toxicity. In this study, the effects of superphosphate and inoculation with the AM fungus Glomus mosseae on P and As uptake of lentil were investigated. Plant height, shoot dry weight, shoot/root P concentration, and shoot P content increased due to mycorrhizal inoculation. However, As concentration in roots/ shoots and root As content were reduced, plant height, shoot dry weight, shoot/root P concentration/ content, and root As concentration and content increased due to superphosphate application. Root P concentration decreased with increasing As concentration. It was apparent that As concentration and content in shoots/roots increased with increasing As concentration in irrigation water. Superphosphate interaction with G. mosseae reduced the role of mycorrhizal infection in terms of enhancing P nutrition and reducing uptake of potentially toxic As into plant parts. The role and relationship of mycorrhizal in respect of P nutrition and As remediation efficiency in plant parts was established. In conclusion, it was worth alluding to that lentil with AM fungal inoculation can reduce As uptake and improve P nutrition. However, in retrospect superphosphate increased P and As uptake and decreased the role of the mycorrhizal association. This resulted in stimulating increased P uptake while decreasing As uptake in lentil.

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