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Bart Muys - One of the best experts on this subject based on the ideXlab platform.
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root tensile strength and root distribution of typical mediterranean plant species and their contribution to soil shear strength
Plant and Soil, 2008Co-Authors: Stijn Baets, Bert Reubens, K Wemans, Jeremie De Baerdemaeker, Jean Poesen, Bart MuysAbstract:In Mediterranean environments, gully erosion is responsible for large soil losses. It has since long been recognized that slopes under vegetation are much more resistant to soil erosion processes compared to bare soils and improve slope stability. Planting or preserving vegetation in areas vulnerable to erosion is therefore considered to be a very effective soil erosion control measure. Re-vegetation strategies for erosion control rely in most cases on the effects of the above-ground biomass in reducing water erosion rates, whereas the role of the below-ground biomass is often neglected or underestimated. While the above-ground biomass can temporally disappear in semi-arid environments, roots may still be present underground and play an important role in protecting the topsoil from being eroded. In order to evaluate the potential of plant species growing in Mediterranean environments to prevent shallow mass movements on gully or terrace walls, the root reinforcement effect of 25 typical Mediterranean matorral species (i.e. shrubs, grasses herbs, small trees) was assessed, using the simple perpendicular model of Wu et al. (Can Geotech J 16:19–33, 1979). As little information is available on Mediterranean plant root characteristics, root distribution data were collected in SE-Spain and root tensile strength tests were conducted in the laboratory. The power root tensile strength–root diameter relationships depend on plant species. The results show that the shrubs Salsola genistoides Juss. Ex Poir. and Atriplex halimus L. have the strongest roots, followed by the grass Brachypodium retusum (Pers.) Beauv. The shrubs Nerium oleander L. and the grass Avenula bromoides (Gouan) H. Scholz have the weakest roots in tension. Root area ratio for the 0–0.1 m topsoil ranges from 0.08% for the grass Piptatherum miliaceum (L.) Coss to 0.8% for the tree Tamarix canariensis Willd. The rush Juncus acutus L. provides the maximum soil reinforcement to the topsoil by its roots (i.e. 304 kPa). Grasses also increase soil shear strength significantly (up to 244 kPa in the 0–0.1 m topsoil for Brachypodium retusum (Pers.) Beauv.). The shrubs Retama sphaerocarpa (L.) Boiss. and Anthyllis cytisoides L. are increasing soil shear strength to a large extent as well (up to 134 and 160 kPa respectively in the 0–0.10 m topsoil). Whereas grasses and the rush Juncus acutus L. increase soil shear strength in the topsoil (0–0.10 m) to a large extent, the shrubs Anthyllis cytisoides (L.), Retama sphaerocarpa (L.) Boiss., Salsola genistoides Juss. Ex Poir. and Atriplex halimus L. strongly reinforce the soil to a greater depth (0–0.5 m). As other studies reported that Wu’s model overestimates root cohesion values, reported root cohesion values in this study are maximum values. Nevertheless, the calculated cohesion values are used to rank species according to their potential to reinforce the soil.
Stijn Baets - One of the best experts on this subject based on the ideXlab platform.
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root tensile strength and root distribution of typical mediterranean plant species and their contribution to soil shear strength
Plant and Soil, 2008Co-Authors: Stijn Baets, Bert Reubens, K Wemans, Jeremie De Baerdemaeker, Jean Poesen, Bart MuysAbstract:In Mediterranean environments, gully erosion is responsible for large soil losses. It has since long been recognized that slopes under vegetation are much more resistant to soil erosion processes compared to bare soils and improve slope stability. Planting or preserving vegetation in areas vulnerable to erosion is therefore considered to be a very effective soil erosion control measure. Re-vegetation strategies for erosion control rely in most cases on the effects of the above-ground biomass in reducing water erosion rates, whereas the role of the below-ground biomass is often neglected or underestimated. While the above-ground biomass can temporally disappear in semi-arid environments, roots may still be present underground and play an important role in protecting the topsoil from being eroded. In order to evaluate the potential of plant species growing in Mediterranean environments to prevent shallow mass movements on gully or terrace walls, the root reinforcement effect of 25 typical Mediterranean matorral species (i.e. shrubs, grasses herbs, small trees) was assessed, using the simple perpendicular model of Wu et al. (Can Geotech J 16:19–33, 1979). As little information is available on Mediterranean plant root characteristics, root distribution data were collected in SE-Spain and root tensile strength tests were conducted in the laboratory. The power root tensile strength–root diameter relationships depend on plant species. The results show that the shrubs Salsola genistoides Juss. Ex Poir. and Atriplex halimus L. have the strongest roots, followed by the grass Brachypodium retusum (Pers.) Beauv. The shrubs Nerium oleander L. and the grass Avenula bromoides (Gouan) H. Scholz have the weakest roots in tension. Root area ratio for the 0–0.1 m topsoil ranges from 0.08% for the grass Piptatherum miliaceum (L.) Coss to 0.8% for the tree Tamarix canariensis Willd. The rush Juncus acutus L. provides the maximum soil reinforcement to the topsoil by its roots (i.e. 304 kPa). Grasses also increase soil shear strength significantly (up to 244 kPa in the 0–0.1 m topsoil for Brachypodium retusum (Pers.) Beauv.). The shrubs Retama sphaerocarpa (L.) Boiss. and Anthyllis cytisoides L. are increasing soil shear strength to a large extent as well (up to 134 and 160 kPa respectively in the 0–0.10 m topsoil). Whereas grasses and the rush Juncus acutus L. increase soil shear strength in the topsoil (0–0.10 m) to a large extent, the shrubs Anthyllis cytisoides (L.), Retama sphaerocarpa (L.) Boiss., Salsola genistoides Juss. Ex Poir. and Atriplex halimus L. strongly reinforce the soil to a greater depth (0–0.5 m). As other studies reported that Wu’s model overestimates root cohesion values, reported root cohesion values in this study are maximum values. Nevertheless, the calculated cohesion values are used to rank species according to their potential to reinforce the soil.
Nicolas Kalogerakis - One of the best experts on this subject based on the ideXlab platform.
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Table_1_Responses of the Endophytic Bacterial Communities of Juncus acutus to Pollution With Metals, Emerging Organic Pollutants and to Bioaugmentation With Indigenous Strains.DOCX
2018Co-Authors: Evdokia Syranidou, Nele Weyens, Jaco Vangronsveld, Sofie Thijs, Marina Avramidou, Danae Venieri, Isabel Pintelon, Nicolas KalogerakisAbstract:Plants and their associated bacteria play a crucial role in constructed wetlands. In this study, the impact of different levels of pollution and bioaugmentation with indigenous strains individually or in consortia was investigated on the composition of the endophytic microbial communities of Juncus acutus. Five treatments were examined and compared in where the wetland plant was exposed to increasing levels of metal pollution (Zn, Ni, Cd) and emerging pollutants (BPA, SMX, CIP), enriched with different combinations of single or mixed endophytic strains. High levels of mixed pollution had a negative effect on alpha diversity indices of the root communities; moreover, the diversity indices were negatively correlated with the increasing metal concentrations. It was demonstrated that the root communities were separated depending on the level of mixed pollution, while the family Sphingomonadaceae exhibited the higher relative abundance within the root endophytic communities from high and low polluted treatments. This study highlights the effects of pollution and inoculation on phytoremediation efficiency based on a better understanding of the plant microbiome community composition.
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Responses of the Endophytic Bacterial Communities of Juncus acutus to Pollution With Metals, Emerging Organic Pollutants and to Bioaugmentation With Indigenous Strains
Frontiers Media S.A., 2018Co-Authors: Nele Weyens, Jaco Vangronsveld, Evdokia Syranidou, Sofie Thijs, Marina Avramidou, Danae Venieri, Isabel Pintelon, Nicolas KalogerakisAbstract:Plants and their associated bacteria play a crucial role in constructed wetlands. In this study, the impact of different levels of pollution and bioaugmentation with indigenous strains individually or in consortia was investigated on the composition of the endophytic microbial communities of Juncus acutus. Five treatments were examined and compared in where the wetland plant was exposed to increasing levels of metal pollution (Zn, Ni, Cd) and emerging pollutants (BPA, SMX, CIP), enriched with different combinations of single or mixed endophytic strains. High levels of mixed pollution had a negative effect on alpha diversity indices of the root communities; moreover, the diversity indices were negatively correlated with the increasing metal concentrations. It was demonstrated that the root communities were separated depending on the level of mixed pollution, while the family Sphingomonadaceae exhibited the higher relative abundance within the root endophytic communities from high and low polluted treatments. This study highlights the effects of pollution and inoculation on phytoremediation efficiency based on a better understanding of the plant microbiome community composition
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responses of the endophytic bacterial communities of Juncus acutus to pollution with metals emerging organic pollutants and to bioaugmentation with indigenous strains
Frontiers in Plant Science, 2018Co-Authors: Nele Weyens, Jaco Vangronsveld, Evdokia Syranidou, Sofie Thijs, Marina Avramidou, Danae Venieri, Isabel Pintelon, Nicolas KalogerakisAbstract:Plants and their associated bacteria play a crucial role in constructed wetlands. In this study, the impact of different levels of pollution and bioaugmentation with indigenous strains individually or in consortia was investigated on the composition of the endophytic microbial communities of Juncus acutus. Five treatments were examined and compared with increasing levels of metal pollution (Zn, Ni, Cd) and emerging pollutants (BPA, SMX, CIP), enriched with different combinations of single or mixed endophytic strains. The responses of the communities of roots and shoots were different, depending on the inoculant and the levels of metals and organic pollutants. The differences in remediation effectiveness and the effects of bioaugmentation were remarkable. Inoculation of the separate strains as well as the consortium significantly enhanced Zn concentrations while it also increased Ni concentrations in the tissues of J. acutus. This study highlights the effects of pollution and inoculation on phytoremediation efficiency based on a better understanding of the plant microbiome community composition. Our results indicate that inoculation with selected indigenous endophytes is a promising approach to improve the efficiency wastewater remediation.
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bisphenol a removal by the halophyte Juncus acutus in a phytoremediation pilot characterization and potential role of the endophytic community
Journal of Hazardous Materials, 2017Co-Authors: Nele Weyens, Jaco Vangronsveld, Evdokia Syranidou, Danae Venieri, Stavros Christofilopoulos, Maria Politi, Nicolas KalogerakisAbstract:A phytoremediation pilot emulating a shallow aquifer planted with Juncus acutus showed to be effective for remediating Bisphenol-A (BPA) contaminated groundwater. Biostimulation with root exudates, low molecular weight organic acids, of J. acutus did not improve BPA-degradation rates. Furthermore, the endophytic bacterial community of J. acutus was isolated and characterized. Many strains were found to possess increased tolerance to metals such as Zn, Ni, Pb and Cd. Moreover, several endophytic bacterial strains tolerated and even used BPA and/or two antibiotics (ciprofloxacin and sulfamethoxazole) as a sole carbon source. Our results demonstrate that the cultivable bacterial endophytic community of J. acutus is able to use organic contaminants as carbon sources, tolerates metals and is equipped with plant-growth promoting traits. Therefore, J. acutus has potential to be exploited in constructed wetlands when co-contamination is one of the restricting factors.
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exploitation of endophytic bacteria to enhance the phytoremediation potential of the wetland helophyte Juncus acutus
Frontiers in Microbiology, 2016Co-Authors: Nele Weyens, Jaco Vangronsveld, Evdokia Syranidou, Sofie Thijs, Stavros Christofilopoulos, Georgia Gkavrou, Nicolas KalogerakisAbstract:This study investigated the potential of indigenous endophytic bacteria to improve the efficiency of the wetland helophyte Juncus acutus to deal with a mixed pollution consisting of emerging organic contaminants and metals. The beneficial effect of bioaugmentation with selected endophytic bacteria was more prominent in case of high contamination: most of the inoculated plants (especially those inoculated with the mixed culture) removed higher percentages of organics and metals from the liquid phase in shorter times compared to the non-inoculated plants without exhibiting significant oxidative stress. When exposed to the lower concentrations, the tailored mixed culture enhanced the performance of the plants to decrease the organics and metals from the water. The composition of the root endophytic community changed in response to increased levels of contaminants while the inoculated bacteria did not modify the community structure. Our results indicate that the synergistic relationships between endophytes and the macrophyte enhance plants’ performance and may be exploited in constructed wetlands treating water with mixed contaminations. Taking into account that the concentrations of emerging organic contaminants used in this study are much higher than the average contents of typical wastewaters, we can conclude that the macrophyte J. acutus with the aid of a mixed culture of tailored endophytic bacteria represents a suitable environmentally friendly alternative for treating pharmaceuticals and metals.
Evdokia Syranidou - One of the best experts on this subject based on the ideXlab platform.
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Table_1_Responses of the Endophytic Bacterial Communities of Juncus acutus to Pollution With Metals, Emerging Organic Pollutants and to Bioaugmentation With Indigenous Strains.DOCX
2018Co-Authors: Evdokia Syranidou, Nele Weyens, Jaco Vangronsveld, Sofie Thijs, Marina Avramidou, Danae Venieri, Isabel Pintelon, Nicolas KalogerakisAbstract:Plants and their associated bacteria play a crucial role in constructed wetlands. In this study, the impact of different levels of pollution and bioaugmentation with indigenous strains individually or in consortia was investigated on the composition of the endophytic microbial communities of Juncus acutus. Five treatments were examined and compared in where the wetland plant was exposed to increasing levels of metal pollution (Zn, Ni, Cd) and emerging pollutants (BPA, SMX, CIP), enriched with different combinations of single or mixed endophytic strains. High levels of mixed pollution had a negative effect on alpha diversity indices of the root communities; moreover, the diversity indices were negatively correlated with the increasing metal concentrations. It was demonstrated that the root communities were separated depending on the level of mixed pollution, while the family Sphingomonadaceae exhibited the higher relative abundance within the root endophytic communities from high and low polluted treatments. This study highlights the effects of pollution and inoculation on phytoremediation efficiency based on a better understanding of the plant microbiome community composition.
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Responses of the Endophytic Bacterial Communities of Juncus acutus to Pollution With Metals, Emerging Organic Pollutants and to Bioaugmentation With Indigenous Strains
Frontiers Media S.A., 2018Co-Authors: Nele Weyens, Jaco Vangronsveld, Evdokia Syranidou, Sofie Thijs, Marina Avramidou, Danae Venieri, Isabel Pintelon, Nicolas KalogerakisAbstract:Plants and their associated bacteria play a crucial role in constructed wetlands. In this study, the impact of different levels of pollution and bioaugmentation with indigenous strains individually or in consortia was investigated on the composition of the endophytic microbial communities of Juncus acutus. Five treatments were examined and compared in where the wetland plant was exposed to increasing levels of metal pollution (Zn, Ni, Cd) and emerging pollutants (BPA, SMX, CIP), enriched with different combinations of single or mixed endophytic strains. High levels of mixed pollution had a negative effect on alpha diversity indices of the root communities; moreover, the diversity indices were negatively correlated with the increasing metal concentrations. It was demonstrated that the root communities were separated depending on the level of mixed pollution, while the family Sphingomonadaceae exhibited the higher relative abundance within the root endophytic communities from high and low polluted treatments. This study highlights the effects of pollution and inoculation on phytoremediation efficiency based on a better understanding of the plant microbiome community composition
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responses of the endophytic bacterial communities of Juncus acutus to pollution with metals emerging organic pollutants and to bioaugmentation with indigenous strains
Frontiers in Plant Science, 2018Co-Authors: Nele Weyens, Jaco Vangronsveld, Evdokia Syranidou, Sofie Thijs, Marina Avramidou, Danae Venieri, Isabel Pintelon, Nicolas KalogerakisAbstract:Plants and their associated bacteria play a crucial role in constructed wetlands. In this study, the impact of different levels of pollution and bioaugmentation with indigenous strains individually or in consortia was investigated on the composition of the endophytic microbial communities of Juncus acutus. Five treatments were examined and compared with increasing levels of metal pollution (Zn, Ni, Cd) and emerging pollutants (BPA, SMX, CIP), enriched with different combinations of single or mixed endophytic strains. The responses of the communities of roots and shoots were different, depending on the inoculant and the levels of metals and organic pollutants. The differences in remediation effectiveness and the effects of bioaugmentation were remarkable. Inoculation of the separate strains as well as the consortium significantly enhanced Zn concentrations while it also increased Ni concentrations in the tissues of J. acutus. This study highlights the effects of pollution and inoculation on phytoremediation efficiency based on a better understanding of the plant microbiome community composition. Our results indicate that inoculation with selected indigenous endophytes is a promising approach to improve the efficiency wastewater remediation.
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bisphenol a removal by the halophyte Juncus acutus in a phytoremediation pilot characterization and potential role of the endophytic community
Journal of Hazardous Materials, 2017Co-Authors: Nele Weyens, Jaco Vangronsveld, Evdokia Syranidou, Danae Venieri, Stavros Christofilopoulos, Maria Politi, Nicolas KalogerakisAbstract:A phytoremediation pilot emulating a shallow aquifer planted with Juncus acutus showed to be effective for remediating Bisphenol-A (BPA) contaminated groundwater. Biostimulation with root exudates, low molecular weight organic acids, of J. acutus did not improve BPA-degradation rates. Furthermore, the endophytic bacterial community of J. acutus was isolated and characterized. Many strains were found to possess increased tolerance to metals such as Zn, Ni, Pb and Cd. Moreover, several endophytic bacterial strains tolerated and even used BPA and/or two antibiotics (ciprofloxacin and sulfamethoxazole) as a sole carbon source. Our results demonstrate that the cultivable bacterial endophytic community of J. acutus is able to use organic contaminants as carbon sources, tolerates metals and is equipped with plant-growth promoting traits. Therefore, J. acutus has potential to be exploited in constructed wetlands when co-contamination is one of the restricting factors.
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exploitation of endophytic bacteria to enhance the phytoremediation potential of the wetland helophyte Juncus acutus
Frontiers in Microbiology, 2016Co-Authors: Nele Weyens, Jaco Vangronsveld, Evdokia Syranidou, Sofie Thijs, Stavros Christofilopoulos, Georgia Gkavrou, Nicolas KalogerakisAbstract:This study investigated the potential of indigenous endophytic bacteria to improve the efficiency of the wetland helophyte Juncus acutus to deal with a mixed pollution consisting of emerging organic contaminants and metals. The beneficial effect of bioaugmentation with selected endophytic bacteria was more prominent in case of high contamination: most of the inoculated plants (especially those inoculated with the mixed culture) removed higher percentages of organics and metals from the liquid phase in shorter times compared to the non-inoculated plants without exhibiting significant oxidative stress. When exposed to the lower concentrations, the tailored mixed culture enhanced the performance of the plants to decrease the organics and metals from the water. The composition of the root endophytic community changed in response to increased levels of contaminants while the inoculated bacteria did not modify the community structure. Our results indicate that the synergistic relationships between endophytes and the macrophyte enhance plants’ performance and may be exploited in constructed wetlands treating water with mixed contaminations. Taking into account that the concentrations of emerging organic contaminants used in this study are much higher than the average contents of typical wastewaters, we can conclude that the macrophyte J. acutus with the aid of a mixed culture of tailored endophytic bacteria represents a suitable environmentally friendly alternative for treating pharmaceuticals and metals.
Bert Reubens - One of the best experts on this subject based on the ideXlab platform.
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root tensile strength and root distribution of typical mediterranean plant species and their contribution to soil shear strength
Plant and Soil, 2008Co-Authors: Stijn Baets, Bert Reubens, K Wemans, Jeremie De Baerdemaeker, Jean Poesen, Bart MuysAbstract:In Mediterranean environments, gully erosion is responsible for large soil losses. It has since long been recognized that slopes under vegetation are much more resistant to soil erosion processes compared to bare soils and improve slope stability. Planting or preserving vegetation in areas vulnerable to erosion is therefore considered to be a very effective soil erosion control measure. Re-vegetation strategies for erosion control rely in most cases on the effects of the above-ground biomass in reducing water erosion rates, whereas the role of the below-ground biomass is often neglected or underestimated. While the above-ground biomass can temporally disappear in semi-arid environments, roots may still be present underground and play an important role in protecting the topsoil from being eroded. In order to evaluate the potential of plant species growing in Mediterranean environments to prevent shallow mass movements on gully or terrace walls, the root reinforcement effect of 25 typical Mediterranean matorral species (i.e. shrubs, grasses herbs, small trees) was assessed, using the simple perpendicular model of Wu et al. (Can Geotech J 16:19–33, 1979). As little information is available on Mediterranean plant root characteristics, root distribution data were collected in SE-Spain and root tensile strength tests were conducted in the laboratory. The power root tensile strength–root diameter relationships depend on plant species. The results show that the shrubs Salsola genistoides Juss. Ex Poir. and Atriplex halimus L. have the strongest roots, followed by the grass Brachypodium retusum (Pers.) Beauv. The shrubs Nerium oleander L. and the grass Avenula bromoides (Gouan) H. Scholz have the weakest roots in tension. Root area ratio for the 0–0.1 m topsoil ranges from 0.08% for the grass Piptatherum miliaceum (L.) Coss to 0.8% for the tree Tamarix canariensis Willd. The rush Juncus acutus L. provides the maximum soil reinforcement to the topsoil by its roots (i.e. 304 kPa). Grasses also increase soil shear strength significantly (up to 244 kPa in the 0–0.1 m topsoil for Brachypodium retusum (Pers.) Beauv.). The shrubs Retama sphaerocarpa (L.) Boiss. and Anthyllis cytisoides L. are increasing soil shear strength to a large extent as well (up to 134 and 160 kPa respectively in the 0–0.10 m topsoil). Whereas grasses and the rush Juncus acutus L. increase soil shear strength in the topsoil (0–0.10 m) to a large extent, the shrubs Anthyllis cytisoides (L.), Retama sphaerocarpa (L.) Boiss., Salsola genistoides Juss. Ex Poir. and Atriplex halimus L. strongly reinforce the soil to a greater depth (0–0.5 m). As other studies reported that Wu’s model overestimates root cohesion values, reported root cohesion values in this study are maximum values. Nevertheless, the calculated cohesion values are used to rank species according to their potential to reinforce the soil.
