scholarly journals Variation of Morphology and Elemental Concentrations in the California Nickel Hyperaccumulator Streptanthus polygaloides (Brassicaceae)

2009 ◽  
Vol 16 (sp5) ◽  
pp. 21 ◽  
Author(s):  
Robert S. Boyd ◽  
Michael A. Wall ◽  
Scott R. Santos ◽  
Michael A. Davis
Keyword(s):  
Elemental Concentrations ◽  
Streptanthus Polygaloides ◽  
Nickel Hyperaccumulator

A systematic assessment of the occurrence of trace element hyperaccumulation in the flora of New Caledonia

2020 ◽  
Vol 194 (1) ◽  
pp. 1-22 ◽  
Author(s):  
Vidiro Gei ◽  
Sandrine Isnard ◽  
Peter D Erskine ◽  
Guillaume Echevarria ◽  
Bruno Fogliani ◽  
...  
Keyword(s):  
Phylogenetic Diversity ◽  
New Caledonia ◽  
Herbarium Specimens ◽  
X Ray ◽  
Systematic Assessment ◽  
Elemental Concentrations ◽  
Nickel Hyperaccumulator ◽  
Xrf Scanning ◽  
Non Destructive

Abstract New Caledonia is a global biodiversity hotspot known for its metal hyperaccumulator plants. X-ray fluorescence technology (XRF) has enabled non-destructive and quantitative determination of elemental concentrations in herbarium specimens from the ultramafic flora of the island. Specimens belonging to six major hyperaccumulator families (Cunoniaceae, Phyllanthaceae, Salicaceae, Sapotaceae, Oncothecaceae and Violaceae) and one to four specimens per species of the remaining ultramafic taxa in the herbarium were measured. XRF scanning included a total of c. 11 200 specimens from 35 orders, 96 families, 281 genera and 1484 species (1620 taxa) and covered 88.5% of the ultramafic flora. The study revealed the existence of 99 nickel hyperaccumulator taxa (65 known previously), 74 manganese hyperaccumulator taxa (11 known previously), eight cobalt hyperaccumulator taxa (two known previously) and four zinc hyperaccumulator taxa (none known previously). These results offer new insights into the phylogenetic diversity of hyperaccumulators in New Caledonia. The greatest diversity of nickel hyperaccumulators occur in a few major clades (Malphigiales and Oxalidales) and families (Phyllanthaceae, Salicaceae, Cunoniaceae). In contrast, manganese hyperaccumulation is phylogenetically scattered in the New Caledonian flora.

Removing Substrate Background in TEM Microanalysis

1974 ◽  
Vol 32 ◽  
pp. 568-569
Author(s):  
John C. Russ ◽  
Nicholas C. Barbi
Keyword(s):  
Electrical Conductivity ◽  
Rapid Growth ◽  
Organic Film ◽  
Absolute Concentration ◽  
Background Signal ◽  
X Ray ◽  
Elemental Concentrations ◽  
Transmission Electron ◽  
Electron Microscopes ◽  
The Continuum

The rapid growth of interest in attaching energy-dispersive x-ray analysis systems to transmission electron microscopes has centered largely on microanalysis of biological specimens. These are frequently either embedded in plastic or supported by an organic film, which is of great importance as regards stability under the beam since it provides thermal and electrical conductivity from the specimen to the grid.Unfortunately, the supporting medium also produces continuum x-radiation or Bremsstrahlung, which is added to the x-ray spectrum from the sample. It is not difficult to separate the characteristic peaks from the elements in the specimen from the total continuum background, but sometimes it is also necessary to separate the continuum due to the sample from that due to the support. For instance, it is possible to compute relative elemental concentrations in the sample, without standards, based on the relative net characteristic elemental intensities without regard to background; but to calculate absolute concentration, it is necessary to use the background signal itself as a measure of the total excited specimen mass.

Localization of calcium and zinc in the sperm storage tubules of chicken, quail and turkey using X-ray microanalysis

Reproduction ◽  
2000 ◽  
pp. 331-336 ◽  
Author(s):  
L Holm ◽  
H Ekwall ◽  
GJ Wishart ◽  
Y Ridderstrale
Keyword(s):  
Calcium Concentration ◽  
Sperm Storage ◽  
X Ray ◽  
Elemental Concentrations ◽  
Low Concentrations ◽  
Intracellular Content ◽  
Wet Weight ◽  
The Mean ◽  
Sperm Storage Tubules ◽  
Scanning Electron

Sperm storage tubules from the utero-vaginal junction of chickens, quails and turkeys were analysed for calcium and zinc using X-ray microanalysis of ultra-rapidly frozen tissue in a scanning electron microscope. This technique enabled the tubular fluid surrounding the stored spermatozoa and the intracellular content of the cells of the sperm storage tubules to be analysed separately and, by using standards with known concentrations, their elemental concentrations were estimated. The mean (+/- SEM) concentration of calcium in the tubular fluid from chickens, quails and turkeys was 17 +/- 3, 19 +/- 3 and 17 +/- 4 mmol kg(-1) wet weight, respectively. The intracellular calcium concentration of the cells of the tubules did not differ significantly from these values and was also similar in the mucosal epithelial cells of the utero-vaginal junction. Zinc was localized in the cells of turkey sperm storage tubules and tubular fluid, but at low concentrations. No zinc could be detected in corresponding structures from chickens and quails. The concentration of calcium in the tubular fluid is within the range known to inhibit the motility of spermatozoa, supporting this function for calcium during storage. Zinc is known to depress turkey sperm metabolism and it may also be involved in inducing quiescence of spermatozoa during storage in this species.

scholarly journals Effect of CO2 on elemental concentrations in recirculating aquaculture system tanks

Aquaculture ◽  
2019 ◽  
Vol 511 ◽  
pp. 734254
Author(s):  
Shazia N. Aslam ◽  
Sharada Navada ◽  
Gisle R. Bye ◽  
Vasco C. Mota ◽  
Bendik Fyhn Terjesen ◽  
...  
Keyword(s):  
Recirculating Aquaculture System ◽  
Elemental Concentrations ◽  
Recirculating Aquaculture ◽  
Aquaculture System

scholarly journals First-Time Source Apportionment Analysis of Deposited Particulate Matter from a Moss Biomonitoring Study in Northern Greece

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 208 ◽  
Author(s):  
Chrysoula Betsou ◽  
Evangelia Diapouli ◽  
Evdoxia Tsakiri ◽  
Lambrini Papadopoulou ◽  
Marina Frontasyeva ◽  
...  
Keyword(s):  
Source Apportionment ◽  
Power Plants ◽  
Soil Dust ◽  
Northern Greece ◽  
Mining Operations ◽  
Moss Species ◽  
Elemental Concentrations ◽  
Pmf Model ◽  
Moss Biomonitoring ◽  
High Concentrations

Moss biomonitoring is a widely used technique for monitoring the accumulation of trace elements in airborne pollution. A total of one hundred and five samples, mainly of the Hypnum cupressiforme Hedw. moss species, were collected from the Northern Greece during the 2015/2016 European ICP Vegetation (International Cooperative Program on Effects of Air Pollution on Natural Vegetation and Crops) moss survey, which also included samples from the metalipherous area of Skouries. They were analyzed by means of neutron activation analysis, and the elemental concentrations were determined. A positive matrix factorization (PMF) model was applied to the results obtained for source apportionment. According to the PMF model, five sources were identified: soil dust, aged sea salt, road dust, lignite power plants, and a Mn-rich source. The soil dust source contributed the most to almost all samples (46% of elemental concentrations, on average). Two areas with significant impact from anthropogenic activities were identified. In West Macedonia, the emissions from a lignite power plant complex located in the area have caused high concentrations of Ni, V, Cr, and Co. The second most impacted area was Skouries, where mining activities and vehicular traffic (probably related to the mining operations) led to high concentrations of Mn, Ni, V, Co, Sb, and Cr.

Sign in / Sign up

Export Citation Format

Share Document