Effects of Ectomycorrhizal Fungi and Heavy Metals (Pb, Zn, and Cd) on Growth and Mineral Nutrition of Pinus halepensis Seedlings in North Africa.

Chadlia Hachani,Zoubeir Béjaoui,Mohammed S Lamhamedi,Susana Gouveia,Damase P Khasa,Abdenbi Zine El Abidine,Claudio Cameselle

doi:10.3390/microorganisms8122033

Abstract

The pollution of soils by heavy metals resulting from mining activities is one of the major environmental problems in North Africa. Mycorrhizoremediation using mycorrhizal fungi and adapted plant species is emerging as one of the most innovative methods to remediate heavy metal pollution. This study aims to assess the growth and the nutritional status of ectomycorrhizal Pinus halepensis seedlings subjected to high concentrations of Pb, Zn, and Cd for possible integration in the restoration of heavy metals contaminated sites. Ectomycorrhizal and non-ectomycorrhizal P. halepensis seedlings were grown in uncontaminated (control) and contaminated soils for 12 months. Growth, mineral nutrition, and heavy metal content were assessed. Results showed that ectomycorrhizae significantly improved shoot and roots dry masses of P. halepensis seedlings, as well as nitrogen shoot content. The absorption of Pb, Zn, and Cd was much higher in the roots than in the shoots, and significantly more pronounced in ectomycorrhizal seedlings—especially for Zn and Cd. The presence of ectomycorrhizae significantly reduced the translocation factor of Zn and Cd and bioaccumulation factor of Pb and Cd, which enhanced the phytostabilizing potential of P. halepensis seedlings. These results support the use of ectomycorrhizal P. halepensis in the remediation of heavy metal contaminated sites.

Highlights

Soil pollution is a serious issue, given that it is considered one of the worst environmental problems in North Africa [1,2]
The purpose of the present study is to assess the growth and mineral nutrition of ectomycorrhizal and non-ectomycorrhizal P. halepensis seedlings that have been subjected to metal stress
The bioaccumulation and translocation factors were less than 1; the presence of ectomycorrhizal fungi further reduced these values (Table 4), which demonstrates that ectomycorrhizae improved the phytostabilization potential of P. halepensis, similar to the findings reported by Gu et al [80]

Summary

Introduction

Soil pollution is a serious issue, given that it is considered one of the worst environmental problems in North Africa [1,2]. Mining activities are among the major sources of heavy metal contamination in soils [3,4]. Mining generates large quantities of waste, which are disposed of as overburden and tailings near the mine These wastes are frequently very rich in metallic ores that persist for a very long time [5]. In North Africa, these mining sites are generally located close to farms that produce foodstuffs for human consumption [6,8,9]. Both the health of humans and ecosystems are at risk, due to exposure to metal contamination [10,11,12]. The remediation of heavy metal-contaminated sites has become a major concern [14]

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Conclusion