Hormonal treatments and mycorrhizal development

International audienc

Chromium Resistant Bacteria: Impact on Plant Growth in Soil Microcosm

Three chromium resistant bacterial strains, Pseudomonas fluorescens PF28, Enterobacter amnigenus EA31 and Enterococcus gallinarum S34 isolated from tannery waste contaminated soil were used in this study. All strains could resist a high concentration of K2Cr2O7 that is up to 300 mg/L. The effect of these strains on clover plants (Trifolium campestre) in the presence of two chromium salts CrCl3 and K2Cr2O7 was studied in soil microcosm. Application of chromium salts adversely affected seed germination, root and shoot length. Bacterial inoculation improved the growth parameters under chromate stress when compared with non inoculated respective controls. There was observed more than 50% reduction of Cr(VI) in inoculated soil microcosms, as compared to the uninoculated soil under the same conditions. The results obtained in this study are significant for the bioremediation of chromate pollution

Heavy Metals Effects on Agricultural Soil Enzyme Activities of Fez, Morocco

Enzyme activities in soils are influenced by soil characteristics and pollutants and could be indicator of soil quality. This study was undertaken to determine the relationship between physicochemical characteristics, heavy metals contents and enzyme activities (EA) in agricultural soils in the Saiss plain (Morocco). The analysis of six agricultural soil samples (sites1-6), collected from urban and periurban agricultural soils of Fez region, showed that soils are generally alkaline with high CaCO3 that rich 46%, EC (525-703µS/cm), rich in Organic matter (3.14-5.80%). The Cr, Cu, Ni, Pb and Zn concentrations in the studied area are generally greater than the Upper Continental Crust, with a deceasing order: Zn> Cr> Pb> Cu> Ni. Geo-accumulation index (Igeo) showed that soils are unpolluted to moderately polluted except site 5 and site 6 that are moderately to strongly polluted by respectively Cu, Pb, Zn and Pb. Potential ecological rіsk factors (Er) were below 40, which means low potential ecological rіsk except site 5 that has moderate potential ecological risk by Cu and Pb. Soil potential ecological risk indices (RI) were found PHOS>GALA. Pearson’s correlation showed significant posіtive correlatіon between studied soil EA and between these EA and heavy metals (Cu, Pb and Zn), and significant negative correlatіon between EA and heavy metals (Cr and Ni). The results of this study enrich and provide data base of the impact of heavy metals on soil enzyme actіvities in agrіcultural soils in the Saiss plain

Effects of gibberellic acid (GA3) treatments on endomycorrhizas

International audienc

Effects of gibberellic acid (GA3) treatments on endomycorrhizas

International audienc

Analyse de l'impact des émissions en éléments traces métalliques sur les sols agricoles irrigués dans la région de Fès. Caractérisation spécifique de l'écotoxicité terrestre par l'Analyse du Cycle de Vie

Analyse de l'impact des émissions en éléments traces métalliques sur les sols agricoles irrigués dans la région de Fès. Caractérisation spécifique de l'écotoxicité terrestre par l'Analyse du Cycle de Vie. Biotechnologie au Service de la Société "BioSeS 2015

The rhizosphere microbiome: A key component of sustainable cork oak forests in trouble

International audienceCork oak (Quercus sober L.) is an emblematic component of western Mediterranean basin landscapes. Cork oak forests have always been highly appreciated by local populations for their great ecological and socio-economic value. However, the sustainability of cork oak forests has been threatened in recent decades by a complex phenomenon of degradation called "oak decline", worsened by the increase of anthropogenic and climatic disturbances combined with a lack or scarcity of natural cork oak regeneration. All these disturbances disrupt key components of the ecosystem, notably the rhizosphere microbiome, potentially sharpening decline processes and forest ecosystem degradation in return. This review provides an overview of the main abiotic and biotic decline drivers and a comprehensive state of knowledge about the impact of decline-related cork oak forest degradation on rhizosphere microbiome in Mediterranean basin. Finally, perspectives for the improvement of cork oak forest sustainability through the development of ecological management strategies based on rhizosphere microbiome-driven plant managements are highlighted

Evaluation of the environmental and human health risk related to metallic contamination in agricultural soils in the Mediterranean semi arid area (Saiss plain, Morocco)

International audienceIn the plain of Saiss, the most agricultural region of Morocco, the studies concerning the assessment of environmental and human risks related to metal contamination of agricultural soils are severely missing. To overcome the lack of such studies, trace-element analyses were carried out on six sampling sites of agricultural surface soils (66 sampling points), irrigated by superficial watercourses with high heavy metal contents. The average trace-element contents were 78, 55, 33, and 119 (mg kg−1), respectively, for Cr, Cu, Ni, and Zn. These values are above average worldwide soil and geochemical background levels. Multivariate statistical analyses, principal component, and cluster analyses suggest that soil contamination by Cr, Cu, and Zn is mainly due to wastewater irrigation, with the exception of Ni, which is probably of pedo-lithogenic origin. To provide further information on contamination transmission, the bioavailability and distribution of the four heavy metals in the soils were studied by sequential and single extractions. The results indicate that Cu and Zn are potentially available and can constitute a potential risk to the environment. The risk assessment of soil contamination was also carried out using risk assessment code, enrichment factor, contamination factor, degree of contamination, pollution lead index, geoaccumulation index, and potential ecological risk factors. The health risk evaluation by the Hazard Index was used to derive a combined risk of soil ingestion, dermal contact, and inhalation for adults and children. According to these indices, the soils present a moderate-to-high contamination for Cu and Zn elements, respectively. Hazard Index values indicate the relative absence of health risks associated to heavy metals for both adults and children