scholarly journals Relative sensitivity of duckweed Lemna minor and six algae to seven herbicides

2021 ◽  
Vol 46 (3) ◽  
pp. 267-273
Author(s):  
Koji Ueda ◽  
Takashi Nagai
Keyword(s):  
Lemna Minor ◽  
Relative Sensitivity

scholarly journals Assessment of Various Toxicity Endpoints in Duckweed (Lemna minor) at the Physiological, Biochemical, and Molecular Levels as a Measure of Diuron Stress

Biology ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 684
Author(s):  
Hojun Lee ◽  
Stephen Depuydt ◽  
Kisik Shin ◽  
Soyeon Choi ◽  
Geonhee Kim ◽  
...  
Keyword(s):  
Aquatic Macrophyte ◽  
Lemna Minor ◽  
Relative Sensitivity ◽  
Photochemical Quenching ◽  
Gene Transcript ◽  
Fresh Weight ◽  
Strong Negative Correlation ◽  
Transcript Levels ◽  
Highly Correlated ◽  
Non Photochemical Quenching

The common, broad-spectrum herbicide diuron poses some risks to the environment due to its long persistence and high toxicity. Therefore, the effective monitoring of diuron residues will inform efforts to assess its impacts on ecosystems. In this study, we evaluated the toxicity targets of diuron in the model aquatic macrophyte Lemna minor at the physiological (growth and photosynthetic efficiency), biochemical (pigment biosynthesis and reactive oxygen species (ROS) levels), and molecular (rbcL transcript) levels. The toxicity of diuron was detectable after 48 h of exposure and the order of sensitivity of toxicity endpoints was gene transcription > maximum electron transport rate (ETRmax) > non-photochemical quenching (NPQ) > maximum quantum yield (Fv/Fm) > ROS > fresh weight > chlorophyll b > chlorophyll a > total frond area > carotenoids. Under diuron stress, pigment, ROS, and gene transcript levels increased while frond area, fresh weight, and photosynthesis (Fv/Fm and ETRmax) gradually decreased with the increasing duration of exposure. Notably, ROS levels, Fv/Fm, frond area, and fresh weight were highly correlated with diuron concentration. The growth endpoints (frond area and fresh weight) showed a strong negative correlation with ROS levels and a positive correlation with Fv/Fm and ETRmax. These findings shed light on the relative sensitivity of different endpoints for the assessment of diuron toxicity.

Low temperature x-ray microanalysis of frozen-hydrated tobacco leaves

1984 ◽  
Vol 42 ◽  
pp. 284-285
Author(s):  
S. Edith Taylor ◽  
Patrick Echlin ◽  
May McKoon ◽  
Thomas L. Hayes
Keyword(s):  
Low Temperature ◽  
Lemna Minor ◽  
Root Tips ◽  
Tobacco Leaves ◽  
X Ray ◽  
Whole Cells ◽  
Carbon Coated ◽  
The Right ◽  
Beam Currents ◽  
The University

Low temperature x-ray microanalysis (LTXM) of solid biological materials has been documented for Lemna minor L. root tips. This discussion will be limited to a demonstration of LTXM for measuring relative elemental distributions of P,S,Cl and K species within whole cells of tobacco leaves.Mature Wisconsin-38 tobacco was grown in the greenhouse at the University of California, Berkeley and picked daily from the mid-stalk position (leaf #9). The tissue was excised from the right of the mid rib and rapidly frozen in liquid nitrogen slush. It was then placed into an Amray biochamber and maintained at 103K. Fracture faces of the tissue were prepared and carbon-coated in the biochamber. The prepared sample was transferred from the biochamber to the Amray 1000A SEM equipped with a cold stage to maintain low temperatures at 103K. Analyses were performed using a tungsten source with accelerating voltages of 17.5 to 20 KV and beam currents from 1-2nA.

Elemental Analysis of Phloem Tissue in Lemna Minor Root Tips

1980 ◽  
Vol 38 ◽  
pp. 798-799
Author(s):  
Patrick Echlin ◽  
Thomas Hayes ◽  
Clifford Lai ◽  
Greg Hook
Keyword(s):  
Vascular Tissue ◽  
Lemna Minor ◽  
Atomic Weight ◽  
Companion Cell ◽  
Root Tips ◽  
Phloem Tissue ◽  
Cell Stage ◽  
Phloem Parenchyma ◽  
Parenchyma Cells ◽  
Xylem Element

Studies (1—4) have shown that it is possible to distinguish different stages of phloem tissue differentiation in the developing roots of Lemna minor by examination in the transmission, scanning, and optical microscopes. A disorganized meristem, immediately behind the root-cap, gives rise to the vascular tissue, which consists of single central xylem element surrounded by a ring of phloem parenchyma cells. This ring of cells is first seen at the 4-5 cell stage, but increases to as many as 11 cells by repeated radial anticlinal divisions. At some point, usually at or shortly after the 8 cell stage, two phloem parenchyma cells located opposite each other on the ring of cells, undergo an unsynchronized, periclinal division to give rise to the sieve element and companion cell. Because of the limited number of cells involved, this developmental sequence offers a relatively simple system in which some of the factors underlying cell division and differentiation may be investigated, including the distribution of diffusible low atomic weight elements within individual cells of the phloem tissue.

Relative Sensitivity of Different Tests in the Detection of Low Titer Lupus Anticoagulants

1988 ◽  
Vol 60 (02) ◽  
pp. 217-219 ◽  
Author(s):  
B Lesperance ◽  
M David ◽  
J Rauch ◽  
C Infante-Rivard ◽  
G E Rivard
Keyword(s):  
Relative Sensitivity ◽  
Fetal Outcome ◽  
Anticardiolipin Antibodies ◽  
Lupus Anticoagulants ◽  
Normal Plasma ◽  
Coagulation Tests ◽  
High Dilutions ◽  
Tissue Thromboplastin ◽  
High Concentrations ◽  
Kaolin Clotting Time

SummaryLupus anticoagulants (LA) and anticardiolipin antibodies have been strongly associated with recurrent abortion and fetal death. Because steroids have been reported to improve the fetal outcome of LA associated pregnancies, presumably by decreasing the levels of LA, it becomes desirable to have a simple and reliable test to monitor the levels of the putative antibody. To this effect, we assessed the capacity of the following coagulation tests to detect the presence of LA in serial dilutions of patient plasma with pooled normal plasma: kaolin clotting time (KCT), tissue thromboplastin inhibition test (TTIT), dilute Russell Viper venom time (DRVVT) and activated partial thromboplastin time with standard and high concentrations of phospholipids (SC and HCAPTT). All samples were also evaluated for the presence of anticardiolipin antibodies with an ELISA. The KCT was able to detect LA at a much greater dilution in normal plasma than any of the other clotting assays. The ELISA was comparable to KCT in its ability to detect high dilutions of LA.

Lenteja de agua (Lemna minor) para el tratamiento de las aguas residuales que provienen del lavado de la fibra de fique (Furcraea bedinghausii)

2016 ◽  
Vol 18 (2) ◽  
pp. 25
Author(s):  
Arnol Arias Hoyos ◽  
Alejandra Ramirez ◽  
Viviana Andrea Fernandez ◽  
Nazly E. Sanchez
Keyword(s):  
Lemna Minor

CEO Compensation and Acquired and Acquiring Companies in Large Corporate Acquisitions

GIS Business ◽  
2016 ◽  
Vol 11 (5) ◽  
pp. 01-13
Author(s):  
Simon Yang
Keyword(s):  
Firm Performance ◽  
Executive Compensation ◽  
Ceo Compensation ◽  
Relative Sensitivity ◽  
Matched Sample ◽  
Executive Pay ◽  
Corporate Acquisitions ◽  
Acquiring Firms ◽  
Managerial Power ◽  
To Receive

This paper examines the relative sensitivity of CEO compensation of both acquiring and acquired firms in the top 30 U.S. largest corporate acquisitions in each year for the period of 2003 to 2012. We find that total compensation and bonus granted to executive compensation for acquired companies, not acquiring companies, are significantly related to the amount of acquisition deal even after the size and firm performance are controlled for. Both acquiring and acquired CEOs are found to make the significantly higher compensation than the matched sample firms in the same industry and calendar year. We also find that executives with higher managerial power, as measured by a lower salary-based compensation mix, prior to a corporate acquisition are more likely to receive a higher executive pay in the year of acquisition. The association between executive compensation and managerial power seems to be stronger for acquired firms than for acquiring firms in corporate acquisition. Overall, our findings suggest that corporate acquisition has higher impacts on executive compensation for acquired firm CEOs than for acquiring firm CEOs.

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