De l'utilisation du lanthane comme traceur de la voie apoplastique chez Cystoseira nodicaulis (Fucales, Cystoseiraceae)

1991 ◽  
Vol 69 (1) ◽  
pp. 18-25 ◽  
Author(s):  
Liliane Pellegrini ◽  
Marie Epiard-Lahaye ◽  
Michel Penot
Keyword(s):  
Cell Walls ◽  
Long Distance ◽  
Long Distance Transport ◽  
Dense Deposits ◽  
Symplasmic Transport ◽  
Apoplastic Pathway ◽  
Distance Transport ◽  
Kinetics Of ◽  
Dense Marker ◽  
Over Time

Lanthanum was used as an electron-dense marker of apoplastic transport in the brown alga Cystoseira nodicaulis. A lanthanum salt, La(NO3)3, was given in seawater at the base of excised branches for 2–8 days. Lanthanum transport into two regions distant from the point of application, the base and apex of the branches, was followed over time by electron microscopy. Restricted localisation of the deposits confirmed that an apoplastic pathway exists in this alga. The kinetics of transport are slow. Dense deposits were located exclusively in the cell walls of meristoderm and cortex cells. The significance of apoplastic transport in algae is discussed in the context of long-distance transport. The existence of an apoplastic route does not exclude the occurrence of symplasmic transport, which is suggested by the numerous plasmodesmata present in the medulla. Key words: algae, apoplast, Cystoseira, lanthanum, long-distance transport.

A study of phloem sieve element structure using electron, fluorescent, and confocal microscopy

1991 ◽  
Vol 49 ◽  
pp. 202-203
Author(s):  
Richard D. Sjolund ◽  
Chi Wang
Keyword(s):  
Cell Walls ◽  
Higher Plants ◽  
Post Injury ◽  
Long Distance ◽  
Callose Deposition ◽  
Sieve Elements ◽  
Long Distance Transport ◽  
P Protein ◽  
Sieve Tubes ◽  
Distance Transport

Phloem sieve elements are the cells responsible for the long distance transport of nutrients, primarily sugars and amino acids, in higher plants. The translocation of nutrients in these cells, joined together to form long sieve tubes, is dependent on the development of high hydrostatic pressures (20 bars or higher). The dissection of plant tissues containing these phloem cells which is necessary for microscopic study usually results in the cutting of the sieve elements and a resultant loss of phloem contents due to the explosive release of the hydrostatic pressure. Wound-sealing mechanisms involving P-protein filaments and callose deposition in the cell walls rapidly seal off wound sites and prevent the loss of translocates, especially in Angiosperms. As a result, most electron microscope images of sieve elements obtained from plant organs reveal post-injury structure following wounding.

The Fine Structure of Phloem Cells

1985 ◽  
Vol 43 ◽  
pp. 632-635
Author(s):  
James Cronshaw
Keyword(s):  
Structural Studies ◽  
High Concentration ◽  
Long Distance ◽  
Phloem Tissue ◽  
Sieve Elements ◽  
Long Distance Transport ◽  
P Protein ◽  
Companion Cells ◽  
Electron Microscopical ◽  
Distance Transport

Long distance transport in plants takes place in phloem tissue which has characteristic cells, the sieve elements. At maturity these cells have sieve areas in their end walls with specialized perforations. They are associated with companion cells, parenchyma cells, and in some species, with transfer cells. The protoplast of the functioning sieve element contains a high concentration of sugar, and consequently a high hydrostatic pressure, which makes it extremely difficult to fix mature sieve elements for electron microscopical observation without the formation of surge artifacts. Despite many structural studies which have attempted to prevent surge artifacts, several features of mature sieve elements, such as the distribution of P-protein and the nature of the contents of the sieve area pores, remain controversial.

scholarly journals Comparative Analysis of Long-Distance Transportation with the Example of Sea and Rail Transport

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1689
Author(s):  
Tomasz Neumann
Keyword(s):  
Eastern China ◽  
Time Cost ◽  
Topsis Method ◽  
Long Distance ◽  
Long Distance Transport ◽  
The Subject ◽  
Transport Analysis ◽  
Multi Criteria Analysis ◽  
The Relationship ◽  
Distance Transport

The subject of the article is a comparative long-distance transport analysis based on the relationship between central and eastern China and Poland. It provides an overview of issues related to long-haul China–Poland. The technique for order of preference by similarity to ideal solution (TOPSIS) method was proposed in the multi-criteria analysis. This method was briefly discussed, and its choice was justified. Then, the criteria adopted in the analysis were presented, i.e., time, cost, maximum number of containers, and ecology index. Multi-criteria analysis was carried out for three cases: the transport of one loading unit, 82 loading units, and 200 loading units. The geopolitical and operational situation on the transport route for the analyzed modes of transport was discussed.

scholarly journals Selecting sorting centres to avoid long distance transport of weaned beef calves

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
T. Morel-Journel ◽  
E. Vergu ◽  
J.-B. Mercier ◽  
N. Bareille ◽  
P. Ezanno
Keyword(s):  
Negative Impact ◽  
Historical Record ◽  
Management Tool ◽  
Long Distance ◽  
Beef Calves ◽  
Long Distance Transport ◽  
And Performance ◽  
Distance Transport ◽  
French Beef ◽  
General Concern

AbstractThe transport of weaned calves from cow–calf producers to fatteners is a general concern for the young bull industry due to its documented negative impact on the welfare, health and performance of the animals. These transfers are often managed by intermediaries who transport weaned calves to sorting centres, where they are grouped into batches before being sent to fattening units. In this study, we present an algorithm to limiting these transfer distances by appropriately selecting the sorting centre through which they must go. We tested the effectiveness of this algorithm on historical data from a French beef producer organization managing 136,892 transfers using 13 sorting centres. The results show a decrease in the transfer distances compared to the historical record, especially for the calves travelling over long distances (− 76 km, i.e. 18% on average for the 33% longest transfers). Moreover, the distribution of calves between the sorting centres proposed by the algorithm reveals differences in their efficiency in minimizing transfer distances. In addition to its usefulness as a management tool for the daily transport of cattle, this algorithm provides prospects for improving the management of the sorting centres themselves.

Correlation of Grassy Lake and Cedar Lake ambers using infrared spectroscopy, stable isotopes, and palaeoentomology

2008 ◽  
Vol 45 (9) ◽  
pp. 1061-1082 ◽  
Author(s):  
Ryan C. McKellar ◽  
Alexander P. Wolfe ◽  
Ralf Tappert ◽  
Karlis Muehlenbachs
Keyword(s):  
Stable Isotopes ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Late Cretaceous ◽  
Western Canada ◽  
Long Distance ◽  
Geochemical Fingerprinting ◽  
Long Distance Transport ◽  
Distance Transport

The Late Cretaceous Grassy Lake and Cedar Lake amber deposits of western Canada are among North America’s most famous amber-producing localities. Although it has been suggested for over a century that Cedar Lake amber from western Manitoba may be a secondary deposit having originated from strata in Alberta, this hypothesis has not been tested explicitly using geochemical fingerprinting coupled to comparative analyses of arthropod faunal content. Although there are many amber-containing horizons associated with Cretaceous coals throughout Alberta, most are thermally mature and brittle, thus lacking the resilience to survive long distance transport while preserving intact biotic inclusions. One of the few exceptions is the amber found in situ at Grassy Lake. We present a suite of new analyses from these and other Late Cretaceous ambers from western Canada, including stable isotopes (H and C), Fourier transform infrared (FTIR) spectra, and an updated faunal compendium for the Grassy and Cedar lakes arthropod assemblages. When combined with amber’s physical properties and stratigraphic constraints, the results of these analyses confirm that Cedar Lake amber is derived directly from the Grassy Lake amber deposit or an immediate correlative equivalent. This enables the palaeoenvironmental context of Grassy Lake amber to be extended to the Cedar Lake deposit, making possible a more inclusive survey of Cretaceous arthropod faunas.

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