Phosphorus uptake and active growth of Elodea canadensis Michx. and Elodea nuttallii (Planch.) St. John

1998 ◽  
Vol 37 (3) ◽  
pp. 59-65 ◽  
Author(s):  
A. H. Eugelink
Keyword(s):  
Phosphorus Uptake ◽  
Elodea Canadensis ◽  
Elodea Nuttallii ◽  
Active Growth ◽  
Uptake Rates ◽  
Significant Difference ◽  
Macrophyte Species ◽  
32P Uptake ◽  
Outdoor Experiments ◽  
Freshwater Macrophyte

Two related submerged freshwater macrophyte (Elodea nuttallii (Planch.) St. John and Elodea canadensis Michx.) were used in a combination of in- and outdoor experiments to compare growth rates and routes of phosphorus uptake, translocation and possible excretion. Elodea nuttalli had a higher growth rate than Elodea canadensis both in the field and under laboratory conditions. The uptake and translocation of phosphorus was studied using 32P in a partitioned container. Roots and leaves were supplied with 32P separately and simultaneously. Both macrophyte species were able to take up phosphorus both with leaves and roots. The uptake rate of 32P by roots was higher in Elodea nuttallii when tracer was supplied to the root compartment only. Leaf uptake was stimulated by the supply of phosphate to both compartments, and the uptake was faster and reached a higher level than when the tracer was injected to the leaf compartment only. The 32P uptake by either roots or leaves was translocated. Shoot-to-root translocation predominated over the reverse. There was no significant difference between both species in root uptake rates, but leaf uptake was significantly higher in Elodea canadensis. The two studied Elodea species do not have a strong preferential source of phosphorus.

scholarly journals Radiographic and computed tomographic assessment of the development of the antebrachia and elbow joints in Labrador Retrievers with and without medial coronoid disease

2015 ◽  
Vol 28 (03) ◽  
pp. 186-192 ◽  
Author(s):  
H. A. W. Hazewinkel ◽  
G. Voorhout ◽  
S. F. Lau
Keyword(s):  
Computed Tomography ◽  
Growth Stage ◽  
Length Ratio ◽  
Active Growth ◽  
Computed Tomographic ◽  
Significant Difference ◽  
Secondary Ossification Centres ◽  
A Prospective Study ◽  
Joint Congruence ◽  
Labrador Retrievers

SummaryObjectives: To compare the development, monitored by radiography and computed tomography, of the antebrachia and elbow joints in seven Labrador Retrievers with healthy elbow joints and in seven Labrador Retrievers that developed medial coronoid disease (MCD), in order to determine whether disturbances in the development of the antebrachia and elbow joints, between the age of six and 17 weeks may lead to medial coronoid disease.Methods: A prospective study of 14 Labrador Retrievers in their active growth stage was performed. The development of the antebrachia and elbow joints was assessed between six and 17 weeks of age using radio graphy and computed tomography determining the development of secondary ossification centres, radioulnar length ratio, radial angulation, and inter-relationship between the humerus, ulna and radius.Results: For the parameters of ossification of secondary ossification centres, radioulnar length ratio, radial angulation, and joint congruence evaluation, there was no significant difference in the development of the ante-brachia and elbow joints of seven Labrador Retrievers positive and seven Labrador Retrievers negative for MCD at the age of six to 17 weeks.Clinical significance: These findings demonstrate that the development of MCD in the Labrador Retrievers in our study was not related to any disturbance in the development of the antebrachia and elbow joints during the rapid growth phase.

Resistance to herbivory of two populations of Elodea canadensis Michaux and Elodea nuttallii Planchon St. John

Plant Ecology ◽  
2011 ◽  
Vol 212 (10) ◽  
pp. 1723-1731 ◽  
Author(s):  
Anatole Boiché ◽  
Damien G. Lemoine ◽  
Marie-Hélène Barrat-Segretain ◽  
Gabrielle Thiébaut
Keyword(s):  
Elodea Canadensis ◽  
Elodea Nuttallii ◽  
Resistance To Herbivory ◽  
Two Populations

Contractile and Ca2+-handling properties of the right ventricular papillary muscle in the late-gestation sheep fetus

2006 ◽  
Vol 101 (3) ◽  
pp. 728-733 ◽  
Author(s):  
T. N. Spencer ◽  
K. J. Botting ◽  
J. L. Morrison ◽  
G. S. Posterino
Keyword(s):  
Right Ventricular ◽  
Papillary Muscle ◽  
Late Gestation ◽  
Postnatal Life ◽  
Excitation Contraction Coupling ◽  
Contraction Coupling ◽  
Force Development ◽  
Uptake Rates ◽  
Significant Difference ◽  
The Right

The force-generating capacity of cardiomyocytes rapidly changes during gestation and early postnatal life coinciding with a transition in cardiomyocyte nucleation in both mice and rats. Changes in nucleation, in turn, appear to coincide with important changes in the excitation-contraction coupling architecture. However, it is not clear whether similar changes are observed in other mammals in which this transition occurs prenatally, such as sheep. Using small (70–300 μM diameter) chemically skinned cardiomyocyte bundles from the right ventricular papillary muscle of sheep fetuses at 126–132 and 137–140 days (d) gestational age (GA), we aimed to examine whether changes in cardiomyocyte nucleation during late gestation coincided with developmental changes in excitation-contraction coupling parameters (e.g., Ca2+ uptake, Ca2+ release, and force development). All experiments were conducted at room temperature (23 ± 1°C). We found that the proportion of mononucleate cardiomyocytes decreased significantly with GA (126–132d, 45.7 ± 4.7%, n = 7; 137–140d, 32.8 ± 1.6%, n = 6; P < 0.05). When we then examined force development between the two groups, there was no significant difference in either the maximal Ca2+-activated force (6.73 ± 1.54 mN/mm2, n = 14 vs. 6.55 ± 1.25 mN/mm2, n = 7, respectively) or the Ca2+ sensitivity of the contractile apparatus (pCa at 50% maximum Ca2+-activated force: 126–132d, 6.17 ± 0.06, n = 14; 137–140d, 6.24 ± 0.08, n = 7). However, sarcoplasmic reticulum (SR) Ca2+ uptake rates (but not Ca2+ release) increased with GA ( P < 0.05). These data reveal that during late gestation in sheep when there is a major transition in cardiomyocyte nucleation, SR Ca2+ uptake rates increase, which would influence total SR Ca2+ content and force production.

scholarly journals Relationships of macrophyte species richness and environment in different water body types in the Central European region

2018 ◽  
Vol 54 ◽  
pp. 35 ◽  
Author(s):  
Kateřina Bubíková ◽  
Richard Hrivnák
Keyword(s):  
Species Richness ◽  
Water Body ◽  
Linear Models ◽  
Aquatic Macrophyte ◽  
European Region ◽  
Central European ◽  
Central European Region ◽  
Significant Difference ◽  
Macrophyte Species ◽  
Trees And Shrubs

Individual types of waterbodies are characterised by their specific environmental conditions controlling growth of aquatic macrophytes. We focused on effects of environmental factors on macrophyte species richness in canals, ponds, rivers and streams within Central European region. We employed generalised linear models (GLM) to assess separately overall macrophyte species data and data on wetland species (true aquatic plants and helophytes). No significant difference was revealed by comparing species richness among water body types, though canals were the richest water bodies and streams supported the lowest diversity of macrophytes. The models for all the waterbodies, except streams, contained at least two variables and the explained variability ranged from 37% to 77%. The most recurring variables were the coverage of fine substrate, turbidity, shading by bank and shore trees and shrubs, and altitude. Nevertheless, no obvious pattern of factors was observed for particular water body types. Our study confirmed that aquatic macrophyte species richness is shaped by a complexity of factors and necessity of targeting survey and further generalisation of results not only on one specific water body.

scholarly journals Management options of invasive Elodea nuttallii and Elodea canadensis

Limnologica ◽  
2015 ◽  
Vol 51 ◽  
pp. 110-117 ◽  
Author(s):  
Andreas Zehnsdorf ◽  
Andreas Hussner ◽  
Frank Eismann ◽  
Helmut Rönicke ◽  
Arnulf Melzer
Keyword(s):  
Elodea Canadensis ◽  
Elodea Nuttallii ◽  
Management Options

Phosphorus Flux through Epilimnetic Zooplankton from Lake Ontario: Relationship with Body Size and Significance to Phytoplankton

1984 ◽  
Vol 41 (11) ◽  
pp. 1702-1712 ◽  
Author(s):  
W. D. Taylor
Keyword(s):  
Body Size ◽  
Phosphorus Uptake ◽  
Lake Ontario ◽  
Trophic Levels ◽  
Phytoplankton Production ◽  
Unit Size ◽  
Release Rates ◽  
Zooplankton Size ◽  
Uptake Rates ◽  
Phosphorus Flux

The flux of phosphate through epilimnetic zooplankton from Lake Ontario was measured by adding 32PO4 into whole lakewater, monitoring its accumulation by zooplankton over 48 h, and then measuring its release when animals were returned to unlabelled lake water. Phosphorus uptake was calculated as the sum of accumulation and release rates. The 10 species examined ranged in size from 36-μm Codonella cratera to 1-mm Daphnia retrocurva. Phosphorus uptake rates of herbivorous zooplankton ranged about 200-fold and increased with body size both within and among species, although not proportionally. Among species, there was a pronounced allometry, with smaller species having much higher rates per unit size. This allometry is similar to that described for other metabolic parameters and body size. There was no tendency for smaller species to release a greater fraction of the label they took up. These results suggest that the biomass of zooplankton consuming a given phytoplankton production will be much smaller if small zooplankton dominate, and therefore, this phosphorus sink will be much smaller. Further, the flow of phosphorus to higher trophic levels may be reduced. The result of changing the zooplankton size-distribution may be to change the amount of spring total phosphorus available to summer phytoplankton.

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