Arsenic uptake by arbuscular mycorrhizal maize (Zea mays L.) grown in an arsenic-contaminated soil with added phosphorus

Abstract

The effects of arbuscular mycorrhizal (AM) fungus (Glomus mosseae) and phosphorus (P) addition (100 mg/kg soil) on arsenic (As) uptake by maize plants (Zea mays L.) from an As-contaminated soil were examined in a glasshouse experiment. Non-mycorrhizal and zero-P addition controls were included. Plant biomass and concentrations and uptake of As, P, and other nutrients, AM colonization, root lengths, and hyphal length densities were determined. The results indicated that addition of P significantly inhibited root colonization and development of extraradical mycelium. Root length and dry weight both increased markedly with mycorrhizal colonization under the zero-P treatments, but shoot and root biomass of AM plants was depressed by P application. AM fungal inoculation decreased shoot As concentrations when no P was added, and shoot and root As concentrations of AM plants increased 2.6 and 1.4 times with P addition, respectively. Shoot and root uptake of P, Mn, Cu, and Zn increased, but shoot Fe uptake decreased by 44.6%, with inoculation, when P was added. P addition reduced shoot P, Fe, Mn, Cu, and Zn uptake of AM plants, but increased root Fe and Mn uptake of the nonmycorrhizal ones. AM colonization therefore appeared to enhance plant tolerance to As in low P soil, and have some potential for the phytostabilization of As-contaminated soil, however, P application may introduce additional environmental risk by increasing soil As mobility.

Arbuscular mycorrhizal symbiosis influences arsenic accumulation and speciation in Medicago truncatula L. in arsenic-contaminated soil

“…The importance of improved P nutrition in the protective effects of mycorrhizal association on host plants against As contaminations has also been observed in our study, which is in accordance with many previous studies Xia et al, 2007;Xu et al, 2008). As been well documented, the improvement of plant P nutrition would directly lead to better plant growth and so-called ''dilution effects'' on As in plant tissues.…”

“…Under As contaminations, AMF could effectively improve plant P nutrition and growth, resulting in a ''dilution effect'' on As in plant tissues Xia et al, 2007;Xu et al, 2008). More importantly, AMF may also directly mediate As uptake by plants.…”

Arsenic uptake and toxicity in plants: integrating mycorrhizal influences

“…In some cases, additional measurements have also demonstrated increases in total (µg/plant) and specific Pi uptake in AM plants. In the same experiments effects on total As(V) content in AM plants were (when measured) quite variable, with values higher than in NM plants observed in both roots and shoots of maize (Xia et al 2007) and lower values in sunflower, medic and lentil (Lens culinaris) (Ahmed et al 2006;Pope 2006;Ultra et al 2007b). Chen et al (2007) point out that increased total As(V) content in responsive AM plants may not solely be the result of transfer via the AM pathway, because more extensive root systems in the larger plants could also make an important contribution on a whole plant basis.…”

“…In these, the symbiosis consistently ameliorates effects of As toxicity, and plants generally show increases in growth compared with NM controls grown at the same As and P supplies in soil (Ahmed et al 2006;Covey et al 1981;Pope et al 2007;Ultra et al 2007b;Xia et al 2007). In some cases, additional measurements have also demonstrated increases in total (µg/plant) and specific Pi uptake in AM plants.…”

Water management, rice varieties and mycorrhizal inoculation influence arsenic concentration and speciation in rice grains

“…It has been well documented that AMF may play an important role in protecting host plants against As contamination Liu et al 2005). AMF essentially improve plant phosphorus (P) nutrition and growth, which could result in a higher P/As ratio and a dilution effect on As in mycorrhizal plants (Ultra et al 2007;Xia et al 2007;Dong et al 2008;Caporale et al 2014;Spagnoletti and Lavado 2015). Smith et al (2010), Christophersen et al (2012), and He and Lilleskov (2014) compared the root and mycorrhizal Pi/arsenate (As(V)) uptake pathways and confirmed the important role of AMF in plant resistance to As contamination.…”