Differences in the effects of three arbuscular mycorrhizal fungal strains on P and Pb accumulation by maize plants

Abstract

The effect of arbuscular mycorrhizal (AM) fungi on the accumulation and transport of lead was studied in a pot experiment on maize plants grown in anthropogenically-polluted substrate. The plants remained uninoculated or were inoculated with different Glomus intraradices isolates, either indigenous to the polluted substrate used or reference from non-polluted soil. A considerably lower tolerance to the conditions of polluted substrate was observed for the reference isolate that showed significantly lower frequency of root colonisation as well as arbuscule and vesicule abundance. Plants inoculated with the reference isolate also had significantly lower shoot P concentrations than plants inoculated with the isolate from polluted substrate. Nevertheless, inoculation with either indigenous or reference G. intraradices isolate resulted in higher shoot and root biomass and inoculated plants showed lower Pb concentrations in their shoots than uninoculated plants, regardless of differences in root colonisation. Root biomass of maize plants was divided according to AM-induced colouration into brightly yellow segments intensively colonised by AM fungus and non-colonised or only slightly colonised whitish ones. Intensively colonised segments of the isolate from polluted substrate contained significantly higher concentrations of phosphorus and lead than non-colonised ones, which suggest significant participation of fungal structures in element accumulation.

Influence of commercial inoculation with Glomus intraradices on the structure and functioning of an AM fungal community from an agricultural site

“…Maize has been shown to respond positively in terms of growth and nutrition to isolates of G. intraradices (e.g., Mickelson and Kaeppler 2005;Sudova and Vosatka 2007), but in our study the inoculant G. intraradices did not affect the host's P content in absence of the resident AM fungal community. This further supports that host-plant responses to individual AM isolates may vary depending on the isolate's interactions with other AM fungi (Gustafson and Casper 2006) in combination with environmental factors (Smith and Smith 1996;Johnson et al 1997).…”

Arbuscular mycorrhiza confers Pb tolerance in Calopogonium mucunoides

“…Sudova and Vosatka (2007) have also concluded that the inoculation of various isolates/ecotypes of the AM fungus, G. intraradices, resulted in a higher tolerance and biomass production of maize plants under Pb stress. All of these results are in agreement with the results obtained in the present study, in which the M plants exhibited a better performance in Pb-contaminated soils than the NM plants, confirming that the accumulation of biomass is a function of AM association.…”

“…Even though there is little available literature regarding the effect of Pb in the Ca content in plants, the results of our study are in accordance with those found by Andrade et al (2003), which have shown that Pb did not cause a reduction in the Ca concentration in soybeans plants, independent of its mycorrhizal status. In a general manner, it was evident that mycorrhization exerted a positive influence in the absorption of certain nutrients, such as Fe, P and S. Sudova and Vosatka (2007) have observed that maize plants associated with G. intraradices in Pb-contaminated soil absorbed lower Pb than non-AM associated plants, whereas Chen et al (2005) have observed that the plants used in their study, grown in Pb-contaminated soil, absorbed more Pb when they were colonized by AM fungi. Because we observed no differences in Pb transportation to the aerial parts up to the moderate Pb dose (500 mg kg -1 ) and a repression of this transportation at the highest Pb dose (1,000 mg kg -1 ), we hypothesize that this feature is likely dependent of the plant and fungus species.…”

Field inoculation of arbuscular mycorrhiza on maize (Zea mays L.) under low inputs: preliminary study on quantitative and qualitative aspects

“…Concentration of heavy metals, e.g. lead, and P in maize plants generally increases when inoculated with arbuscular mycorrhizal fungi, which suggest significant participation of fungal structures in element accumulation (Sudova and Vosatka, 2007). A previous work established that improved P nutrition at early stages of maize growth is reflected in the final maize yield (Gavito and Miller, 1998).…”