The effect of salinity gradient and heavy metal pollution on arbuscular mycorrhizal fungal community structure in some Algerian wetlands

Algerian natural wetlands suffer from anthropogenic disturbances due to industrial development and urbanization. This study was designed to draw attention to arbuscular mycorrhizal fungi (AMF) distribution and community assemblages following heavy metal and salinity concentrations in two wetlands subjected to domestic and industrial effluents. Rhizospheric soil and roots of 18 plant species were collected in two wetlands along a decreasing salinity gradient. The results showed that 72.72% of plant species exhibit an association within arbuscular mycorrhizas (AM), and 36.36% a dual association between AM and dark septate endophytes (DSE). A total of 33 AMF morphospecies were distinguished on the basis of morphological criteria dominated by taxa belonging to Glomeraceae and Acaulosporaceae. Soil contamination was investigated by determining metallic trace elements (MTE) (Cd, Cu, Ni, Pb, Cr and Zn) using an atomic absorption spectrophotometer. Values of the pollution index revealed wetlands that were particularly polluted by lead. Two˗way ANOVA showed significant variations in metal content among sampling locations and transects. Principal component analysis showed that species richness, and mycorrhizal frequency were slightly affected by MTE. This opens possibilities for their utilization in polluted soil remediation

Growth and mycorrhizal responses to cadmium stress in some halophytic plants

2Abdelhamid Ibn Badis University, Mostaganem, Algeria. The phytoremedial potential of three halophytes and the role of arbuscular mycorrhizal fungi (AMF) isolated from heavy metal contaminated soil under cadmium stress were studied. The plants were treated with different Cd concentrations (0, 50, 200, and 400 µM) with and without AMF inoculation. On the plant growth, AMF inoculation to all species resulted in increased biomass, shoots and roots length, and leave number compared to control (non-inoculated) plants, especially in Limbarda crithmoides, where no mortality was detected neither in controls nor inoculants. Furthermore, L. crithmoides and Atriplex canescens recorded higher values of relative mycorrhizal dependency and water content. The arbuscular mycorrhizal association was observed in all host plants and was not affected by cadmium. Our results indicate that studied halophytes can tolerate high Cd concentrations due to the support of AMF, particularly in Atriplex halimus association with AMF in pot experiment which was recorded for the first time

The beneficial role of indigenous arbuscular mycorrhizal fungi in phytoremediation of wetland plants and tolerance to metal stress

The potential of fi ve plants namely Atriplex halimus L., A. canescens (Pursh) Nutt., Suaeda fruticosa (Forssk. ex J.F. Gmel.), Marrubium vulgare L. and Dittrichia viscosa (L.) Greuter from two selected wetlands in northwest Algeria subjected to house and industrial effluents were examined to assess their arbuscular mycorrhizal fungal (AMF) diversity and colonization, as well as to determine their tolerance and ability in accumulating metallic trace elements (MTEs). The purpose was to investigate whether, or not, these fungi are related to metallic uptake. Arbuscular mycorrhizal association was observed in all plant species, since the dual association between AMF and dark septate endophytes (DSE) was found in roots of 80% plants species. Hence, the decreasing trend of metal accumulation in most plant organs was Zn>Cu>Pb, and the most efficient species were M. vulgare> S. fruticosa>A. canescens> D. viscosa> A. halimus. The bioaccumulator factors exceeded the critical value (1.0) and the transport factors indicated that all these species were phytoremediators. Pearson correlation showed that Cd bioaccumulation and translocation were inhibited by AMF infection; meanwhile Zn, Pb and Cd accumulation were affected by AMF spore density and species richness, DSE frequency, pH, AMF and plant host. Native halophytes showed a multi-metallic resistance capacity in polluted wetlands. M. vulgare was the most efficient in metal accumulation and the best host for mycorrhizal fungi. AMF played a major role in metal accumulation and translocation