Uptake Kinetics of Arsenic in Upland Rice Cultivar Zhonghan 221 Inoculated with Arbuscular Mycorrhizal Fungi

Abstract

Arbuscular mycorrhizal fungi (AMF) appear to be highly associated with arsenic (As) uptake in host plants because arsenate (As(V)) and phosphorus (P) share the same transporter, whereby AMF can enhance P uptake. A short-term experiment was conducted for low- (0 to 0.05 mM As) and high-affinity (0 to 2.5 mM As) uptake systems, to investigate the AMF role on As uptake mechanism in plants, which may explain As uptake kinetics in upland rice cultivar: Zhonghan 221. When concentration of As ranged from 0 to 0.05 mM, Funneliformis geosporum (Fg) significantly decreased arsenite (As(III)) and monomethylarsonicacid (MMA) uptake when (p < 0.05) compared to non-mycorrhizal (NM) treatment, since the major route for (As(III)) in rice roots-rice silicon transporter Lsi1 would be influenced by Fg inoculation at high As concentrations. Fg can also reduce As(V) uptake significantly (p < 0.05) under both uptake systems relative to NM treatment, whereas, Funneliformis mosseae (Fm) increased As(V) and MMA uptake in rice roots, with MMA uptake rate generally lower than As(III) and As(V). Using suitable AMF species inoculation with rice, As uptake and accumulation in rice grains can be reduced and the risk to human health, once consumed, can be minimized.

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

“…Moreover, R. irregularis led to elevated As(III)/As(V) ratios in roots (Li et al 2013). Furthermore, Chan et al (2015) reported reduced As(III) and As(V) uptake by paddy rice Zhonghan 221 in mycorrhizal plants compared to non-mycorrhizal controls. Although mycorrhiza-mediated As accumulation and speciation have been reported in rice tissues, the potential influence of AMF on As speciation in rice grains has so far not been investigated.…”