scholarly journals Root and Shoot Response to Nickel in Hyperaccumulator and Non-Hyperaccumulator Species

Plants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 508
Author(s):  
Stefano Rosatto ◽  
Mauro Mariotti ◽  
Sara Romeo ◽  
Enrica Roccotiello
Keyword(s):  
Plant Development ◽  
Root Surface ◽  
Metal Stress ◽  
Physiological Conditions ◽  
Thlaspi Arvense ◽  
Noccaea Caerulescens ◽  
Spiked Soil ◽  
Ecophysiological Response ◽  
Fluorescence Of Chlorophyll A ◽  
Root Surfaces

The soil–root interface is the micro-ecosystem where roots uptake metals. However, less than 10% of hyperaccumulators’ rhizosphere has been examined. The present study evaluated the root and shoot response to nickel in hyperaccumulator and non-hyperaccumulator species, through the analysis of root surface and biomass and the ecophysiological response of the related aboveground biomass. Ni-hyperaccumulators Alyssoides utriculata (L.) Medik. and Noccaea caerulescens (J. Presl and C. Presl) F.K. Mey. and non-hyperaccumulators Alyssum montanum L. and Thlaspi arvense L. were grown in pot on Ni-spiked soil (0–1000 mg Ni kg−1, total). Development of root surfaces was analysed with ImageJ; fresh and dry root biomass was determined. Photosynthetic efficiency was performed by analysing the fluorescence of chlorophyll a to estimate the plants’ physiological conditions at the end of the treatment. Hyperaccumulators did not show a Ni-dependent decrease in root surfaces and biomass (except Ni 1000 mg kg−1 for N. caerulescens). The non-hyperaccumulator A. montanum suffers metal stress which threatens plant development, while the excluder T. arvense exhibits a positive ecophysiological response to Ni. The analysis of the root system, as a component of the rhizosphere, help to clarify the response to soil nickel and plant development under metal stress for bioremediation purposes.

scholarly journals In Situ Phylogenetic Structure and Diversity of Wild Bradyrhizobium Communities

2009 ◽  
Vol 75 (14) ◽  
pp. 4727-4735 ◽  
Author(s):  
J. L. Sachs ◽  
S. W. Kembel ◽  
A. H. Lau ◽  
E. L. Simms
Keyword(s):  
Host Species ◽  
Root Surface ◽  
Small Subset ◽  
Root Tips ◽  
Phylogenetic Structure ◽  
Pure Cultures ◽  
Nodulation Status ◽  
Host Infection ◽  
Root Surfaces

ABSTRACTBacteria often infect their hosts from environmental sources, but little is known about how environmental and host-infecting populations are related. Here, phylogenetic clustering and diversity were investigated in a natural community of rhizobial bacteria from the genusBradyrhizobium. These bacteria live in the soil and also form beneficial root nodule symbioses with legumes, including those in the genusLotus. Two hundred eighty pure cultures ofBradyrhizobiumbacteria were isolated and genotyped from wild hosts, includingLotus angustissimus,Lotus heermannii,Lotus micranthus, andLotus strigosus. Bacteria were cultured directly from symbiotic nodules and from two microenvironments on the soil-root interface: root tips and mature (old) root surfaces. Bayesian phylogenies ofBradyrhizobiumisolates were reconstructed using the internal transcribed spacer (ITS), and the structure of phylogenetic relatedness among bacteria was examined by host species and microenvironment. Inoculation assays were performed to confirm the nodulation status of a subset of isolates. Most recovered rhizobial genotypes were unique and found only in root surface communities, where little bacterial population genetic structure was detected among hosts. Conversely, most nodule isolates could be classified into several related, hyper-abundant genotypes that were phylogenetically clustered within host species. This pattern suggests that host infection provides ample rewards to symbiotic bacteria but that host specificity can strongly structure only a small subset of the rhizobial community.

scholarly journals Effectiveness of EDTA and EDTA-T brushingm on the removal of root surface smear layer

2003 ◽  
Vol 17 (4) ◽  
pp. 319-325 ◽  
Author(s):  
José Eduardo Cezar Sampaio ◽  
Ricardo Samih Georges Abi Rached ◽  
Gibson Luiz Pilatti ◽  
Letícia Helena Theodoro ◽  
Luiz Henrique Carvalho Batista
Keyword(s):  
Root Surface ◽  
Smear Layer ◽  
Treatment Modalities ◽  
Control Group ◽  
Group Iii ◽  
Layer Removal ◽  
Group I ◽  
Control Application ◽  
Root Surfaces ◽  
Gel Ph

The purpose of this study was to compare the removal of root surface smear layer following active application of EDTA gel and EDTA-T (texapon) gel in different concentrations (5%, 10%, 15%, 20% and 24%), using scanning electron microscopy. A total of 220 dentin blocks obtained from the root surfaces of extracted teeth were divided into 3 groups: Group I - (control) application of saline solution (n = 20); Group II - EDTA gel (pH 7.0) was applied in the following concentrations: 5%, 10%, 15%, 20% and 24% (n = 100); Group III - EDTA-T gel (pH 7.0) applied in the same concentrations described above (n = 100). The photomicrographs were evaluated by one calibrated examiner using a smear layer removal index and following statistical analysis (Kruskal-Wallis test). The results demonstrated that the specimens treated with EDTA and EDTA-T gel presented a better smear layer removal than the control group (p < 0.01); no statistically significant differences were observed between the EDTA and EDTA-T groups and between the concentrations tested (Mann-Whitney, p > 0.05). Within the limits of this study, it can be concluded that all treatment modalities effectively removed the smear layer from the root surface. The addition of texapon into the EDTA gel formulation did not increase its effectiveness.

Root Surface Resorption in Two Cases of Rapid Maxillary Expansion

1982 ◽  
Vol 9 (1) ◽  
pp. 37-40 ◽  
Author(s):  
L. Odenrick ◽  
E. Lilja ◽  
K-F. Lindbäck
Keyword(s):  
Active Surface ◽  
Root Surface ◽  
Rapid Maxillary Expansion ◽  
Histological Investigation ◽  
Maxillary Expansion ◽  
Maxillary Premolars ◽  
Root Surfaces ◽  
Expansion Period

The purpose of the present investigation was to study the root surfaces of maxillary first premolars after rapid maxillary expansion. In one girl and one boy with posterior skeletal cross-bites and bimaxillary crowding, midpalatal expansion appliances anchored to the first maxillary premolars and molars were used. After the transversal expansion period all first premolars were examined radiographically and then extracted and investigated histologically. The histological investigation revealed active surface resorption of the maxillary first premolars.

The Effect of EDTA on the Attachment and Growth of Cultured Human Gingival Fibroblasts on Periodontitis-Affected Root Surface

2001 ◽  
Vol 2 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Nadir Babay
Keyword(s):  
Culture Medium ◽  
Root Surface ◽  
Gingival Fibroblasts ◽  
Human Teeth ◽  
Group Iii ◽  
Group I ◽  
Severe Periodontitis ◽  
Diseased Root ◽  
Migration Of Cells ◽  
Root Surfaces

Abstract The purpose of the present study was to analyze the effects of 5% and 24% EDTA on the attachment of gingival fibroblasts to periodontally diseased root surfaces. A flat root surface was created on human teeth that were extracted due to severe periodontitis. The teeth were etched with the following concentrations of etylediaminetetraacetic acid (EDTA) for two minutes: 5% (group I) and 24% (group II). Group III was soaked in saline and served as a control. The specimens and fibroblasts were incubated in a culture medium for 24 hours each day for one and two weeks and photographed using scanning electron microscopy. Each specimen was examined for the migration of cells into the etched and nonetched root surface. No fibroblasts could be detected on the saline groups. More fibroblasts could attach to the surface treated with 24% EDTA than with 5% EDTA. It was concluded that supersaturated EDTA at 24% enhances the attachment of gingival fibroblasts to the root surface.

scholarly journals Emergent Macrophytes Act Selectively on Ammonia-Oxidizing Bacteria and Archaea

2012 ◽  
Vol 78 (17) ◽  
pp. 6352-6356 ◽  
Author(s):  
Rosalia Trias ◽  
Olaya Ruiz-Rueda ◽  
Arantzazu García-Lledó ◽  
Ariadna Vilar-Sanz ◽  
Rocío López-Flores ◽  
...  
Keyword(s):  
Plant Species ◽  
Coastal Wetlands ◽  
Root Surface ◽  
Ammonia Oxidizing Bacteria ◽  
Bulk Sediment ◽  
Emergent Macrophytes ◽  
Root Surfaces

ABSTRACTAmmonia-oxidizing bacteria (AOB) and archaea (AOA) were quantified in the sediments and roots of dominant macrophytes in eight neutral to alkaline coastal wetlands. The AOA dominated in most samples, but the bacterial-to-archaealamoAgene ratios increased with increasing ammonium levels and pH in the sediments. For all plant species, the ratios increased on the root surface relative to the adjacent bulk sediment. This suggests that root surfaces in these environments provide conditions favoring enrichment of AOB.

scholarly journals Protection Offered by Root-surface Restorative Materials against Biofilm Challenge

2007 ◽  
Vol 86 (5) ◽  
pp. 431-435 ◽  
Author(s):  
H.K. Yip ◽  
J. Guo ◽  
W.H.S. Wong
Keyword(s):  
Resin Composite ◽  
Glass Ionomer Cement ◽  
Root Surface ◽  
Glass Ionomer ◽  
Streptococcus Sobrinus ◽  
Oral Biofilm ◽  
Artificial Mouth ◽  
Restorative Materials ◽  
Root Surfaces ◽  
Ionomer Cement

The prevalence of root-surface caries is increasing. We hypothesized that some restorative materials are protective against cariogenic challenge on root surfaces. Our goal was to study the effects of different restorative materials on root surfaces incubated with an oral biofilm generated in an artificial mouth. A biofilm of Streptococcus mutans, Streptococcus sobrinus, Lactobacillus rhamnosus, and Actinomyces naeslundii was co-cultured for 21 days on 24 glass-ionomer cement, resin-modified glass-ionomer cement, or resin-composite-restored root surfaces. These surfaces were then examined with Fourier transform infrared spectroscopy and scanning electron energy-dispersive spectroscopy. Only glass-ionomer restorations showed a significant increase in log calcium-to-phosphorus ratio (P < 0.01), and a significantly lower log amide I-to-hydrogen phosphate ratio on the root surface after incubation in the artificial mouth. Glass-ionomer restoratives conferred a preventive effect on the root surfaces against initial cariogenic challenge with a mixed-species oral biofilm without therapeutic intervention.

scholarly journals Evaluation of caries – protective effect of three recent dentin bonding agents, xeno v plus, tetric n bond ,one coat seven universal on demineralized root surface "- An in vitro study

2019 ◽  
pp. 29-41
Author(s):  
Tanvi Dugge ◽  
Balaram Naik
Keyword(s):  
Protective Effect ◽  
Root Surface ◽  
Bonding Agent ◽  
Control Group ◽  
Human Teeth ◽  
Bonding Agents ◽  
Dentin Bonding ◽  
Rectangular Window ◽  
Root Surfaces

Background and objectives: An area on the surface of tooth, apical to CEJ, where root caries are bound to occur undergoes clinically apparent dissolution of the calcified tissues. When dentin bonding agent is applied, it forms finger like resin tags protruding into patent dentin tubules When this resin penetrates the superficially demineralized collagen matrix, it forms a hybrid layerand prevents root surface lesions. Aim: To evaluate the caries protective effect of three recent DBAs on demineralized root surface. Materials and methods: 88 single rooted extracted human teeth were selected, root surfaces apical to CEJ were polished .Acid resistant nail paint wascoated over root surfaces exposing a rectangular window on the buccal surface. Three experimental groups made: Group 1 (XENO V PLUS), Group 2 (TETRIC N BOND), Group 3 (ONE COAT 7 UNIVERSAL). These groups were divided into 2 Subgroups (A and B). Adhesive was applied and light cured with air thinning. Over this second layer of adhesive was applied, light cured with /without air thinning. Each tooth samples were sliced. A light microscope was used to examine the caries like lesions.The statistical analysis was carried out. Results:All control group specimen showed lesions with a mean depth of 177.74μm. Subgroup B results were better than A and C. Summary and Conclusion: Demineralization on root surface can be impeded by DBA tested TetricN Bond which showed maximum cariesprotective effect Key words:Cementum, demineralization, dentine bonding agent

Patterns of initial saprophytic fungal colonization of grass roots from two severely disturbed soils

1984 ◽  
Vol 62 (3) ◽  
pp. 596-602 ◽  
Author(s):  
John C. Zak ◽  
Dennis Parkinson
Keyword(s):  
Rare Species ◽  
Oil Sands ◽  
Species Turnover ◽  
Species Abundance ◽  
Growing Season ◽  
Root Surface ◽  
Fungal Colonization ◽  
Nodal Roots ◽  
Fungal Assemblages ◽  
Root Surfaces

Development of the root-surface fungal assemblages of Agropyron trachycaulum grown on amended oil-sands tailings and a subalpine coal-mine spoil from Alberta (Canada) was followed over one growing season. Fungi were isolated, using a root-washing procedure, from the region of main seminal and nodal roots 4 cm from the root–hypocotyl axis. Fungal colonization of the root surfaces was rapid, with equilibrium numbers of species reached 2 weeks after plant emergence. Although the application of either fertilizer, peat, or sewage sludge to these spoils had no effect on the general form of the colonization curve, peat amendation did result in significantly higher numbers of species on the root surfaces. Species turnover within all assemblages was high throughout the growing season. The amount of species replacement ranged from a low of 67% to a high of 91% between consecutive 4-week sampling periods. Thus, although the number of species was relatively constant, species composition changed considerably. The structure of the root-surface fungal assemblages was characterized by a large proportion of rare species. The species abundance distributions were essentially negative exponential. Neither time nor amendation had any significant effect on these distributions. The large incidence of rare species within the assemblages suggests that these root surfaces represent nonequilibrium systems with respect to species occurrences.

scholarly journals Comparative in vitro study of root roughness after instrumentation with ultrasonic and diamond tip sonic scaler

2006 ◽  
Vol 14 (2) ◽  
pp. 124-129 ◽  
Author(s):  
Fernanda Vieira Ribeiro ◽  
Renato Correa Viana Casarin ◽  
Francisco Humberto Nociti Júnior ◽  
Enilson Antônio Sallum ◽  
Antonio Wilson Sallum ◽  
...  
Keyword(s):  
Surface Roughness ◽  
In Vitro Study ◽  
Root Surface ◽  
Control Group ◽  
Human Teeth ◽  
Treatment Groups ◽  
Before And After ◽  
Root Surfaces ◽  
Scanning Electron

OBJECTIVE: The purpose of this study was to evaluate the root surface roughness after instrumentation with hand curette and diamond-coated sonic and universal ultrasonic tips. MATERIALS AND METHODS: Forty root surfaces of human teeth were randomly assigned to four treatment groups: control group (without instrumentation), curette instrumentation, ultrasonic instrumentation with universal tip and sonic instrumentation with diamond-coated tip. Each sample was instrumented with fifteen strokes. Before and after instrumentation, surface roughness was measured. In addition, the root surface topography was examined after treatment under the scanning electron microscope. RESULTS: Significant statistical differences (p <0.05) were observed when comparing the control group (0.48±0.07mm) to the treated groups (hand - 1.246±0.279mm, ultrasonic - 1.468±0.177mm and sonic instrumentation - 1.576±0.20mm). The highest roughness was produced by diamond-coated sonic tip and by ultrasonic universal tip (p >0.05). CONCLUSION: The diamond-coated tip with sonic scaler instrumentation and ultrasonic instrumentation produce similar root surface roughness, higher than curette instrumentation.

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