Influence of arbuscular mycorrhizal fungi and an improving growth bacterium on Cd uptake and maize growth in Cd-polluted soils

Abstract

In a pot experiment, the effects of the bacterium strain Micrococcus roseus, native soil arbuscular mycorrhizal fungi (AMF) and the fungus Glomus mosseae on the growth, P, N, Fe, Mn, Zn and Cd uptake of maize in a soil polluted with Cd were investigated. A three-factor experiment was set up in a randomized complete design with three replicates of each treatment. The factors in the experiment were as follows: 1) AMF with two levels, G 1 (native AMF) and G 2 (G. mosseae + G 1 ); 2) bacterium promoting plant growth with two levels, B 0 (no inoculation) and B 1 (inoculation with M. roseus); and 3) cadmium with three levels (0, 100 and 200 mg Cd kg -1 soil). G 2 significantly increased root colonization, plant biomass, shoot nutrients and Cd uptake of plants in comparison with G 1 in Cd polluted conditions. The single presence of AMF contributed to the stabilization of Cd in roots and soil. Shoot and root dry weights, and shoot nutrients uptake of plants co-inoculated with bacterium and AMF were higher than mycorrhizal plants in the soil polluted with Cd. Plants co-inoculated with bacterium and G 2 had higher amount of shoot Cd uptake, root Cd uptake, Cd phytoextraction, translocation, and uptake efficiencies under both Cd concentrations than only mycorrhizal plants. The results showed that, most of the Cd was sequestered in roots of plants co-inoculated with bacterium and native AMF in the soil with 100 and 200 mg Cd kg -1 . Additional key words: cadmium; Glomus mosseae; Micrococcus roseus; native AMF; phytoremediation; Zea mays L. ResumenInfluencia de los hongos micorrícicos arbusculares y de una bacteria promotora del crecimiento en la absorción de Cd y el crecimiento del maíz en suelos contaminados con Cd Se investigaron, en un experimento en macetas, los efectos de la bacteria Micrococcus roseus, hongos micorrícicos arbusculares (AMF) nativos del suelo y el hongo Glomus mosseae en el crecimiento, así como en la absorción de P, N, Fe, Mn, Zn y Cd por el maíz en un suelo contaminado con Cd. Se estableció un experimento trifactorial en un diseño completamente al azar con tres repeticiones por tratamiento. Los factores fueron: 1) AMF con dos niveles, G 1 (AMF nativos) y G 2 (G. mosseae + G 1 ), 2) bacterias promotoras del crecimiento de las plantas con dos niveles, B 0 (sin inoculación) y B 1 (inoculación con M. roseus); y 3) cadmio a tres niveles (0, 100 y 200 mg Cd kg -1 suelo). En condiciones de contaminación con Cd, G 2 aumentó significativamente, comparado con G 1 , la colonización de las raíces, la biomasa vegetal, y la absorción de nutrientes y Cd en los brotes de las plantas. La sola presencia de AMF contribuyó a la estabilización de Cd en las raíces y el suelo. En el suelo contaminado con Cd, el peso seco de los brotes y las raíces, y la absorción de los nutrientes de los brotes en las plantas coinoculadas con la bacteria y los AMF fueron mayores que en las plantas micorrizadas. Las plantas coinoculadas con la bacteria y G 2 presentaron mayor cantidad de absorción de Cd en los brotes y raíces, fitoe...

Effects of Arbuscular Mycorrhizal Fungi on Metals Uptake, Physiological and Biochemical Response of <i>Medicago Sativa</i> L. with Increasing Zn and Cd Concentrations in Soil

“…The results also indicated that Cd and Zn toxicity had no negative effect on root colonization of plants with AM fungi interaction as compared to plants with no fungal interaction. The same results were reported by [28] [29]. The growth inhibition in plants grown under high levels of Zn and Cd was due to interference of these metals with P uptake by plants.…”

Screening mined-out indigenous mycorrhizal fungi for the rehabilitation of mine tailing areas in the Philippines

“…This study used indigenous AMF, which were associated with indigenous ferns in the gullies and few grasses on the plateau of the mined-out areas. Several studies demonstrated the effectiveness of indigenous AMF in stimulating plant growth in heavy metal contaminated sites (Gildon and Tinker 1983;Diaz et al 1996;Cabello 1999;Malekzadeh et al 2011). Some studies had reported otherwise (Enktuya et al 2000).…”

Research Progress and Potential Functions of AMF and GRSP in the Ecological Remediation of Metal Tailings

“…Mycorrhizal fungi can achieve morphological transformation of trace elements in the rhizosphere soil through various pathways, in-cluding chemical precipitation in the soil through acidification and immobilization [44]. The AMF could improve plant tolerance to metals by different mechanisms such as (1) metal restriction by compounds (e.g., glomalin) secreted by AMF [45], Qiu et al [46] found that the significant negative correlation between GRSP and the combined indicators of eight bioavailable metals' concentration, (2) accumulation of metals on the hyphal surface [47], metal adsorption onto substance (e.g., chitin) in the cell walls [48], to reduce the metals translocation to the host plant, (3) AMF increases the content of phosphorus in the soil, metal deposition in polyphosphate particles in the soil [49,50], (4) alteration of metals availability by changing the rhizosphere pH [51], (5) regulation of gene expression under stress conditions [52], AMF symbiosis up-regulated metallothionein PtMT2b in roots regardless of contamination, PtMT2b greatly increased Cd tolerance in transgenic yeast under Cd stress [53], AMF colonization distinctly reduced the level of MsPCS1 and MsMT2 genes, thereby reducing Cd translocation to the aboveground biomass [54]. One study has demonstrated a significant increase in the biomass of AMF-inoculated plants in soils contaminated with Cd.…”