PLASMODESMAL MODIFICATIONS AND DISTRIBUTION OF TOSPO VIRUS IN POTATO AND TOMATO

1999 ◽  
Vol 47 (4) ◽  
pp. 245-250 ◽  
Author(s):  
Ishwar D. Garg ◽  
S.M. Paul Khurana
Keyword(s):  
Long Distance ◽  
Phloem Tissue ◽  
Cortical Cells ◽  
Electron Dense Material ◽  
Phloem Parenchyma ◽  
Long Distance Transport ◽  
Infected Tomato ◽  
Sieve Tubes ◽  
The One ◽  
Distance Transport

The tospovirus isolate on tomato was found to be systemic while the one on potato was non-systemic. The virus was present in all the tissues except xylem vessels in tomato, while it was often found only in the cortical cells of potato stems. Virions were detected in all cells of phloem tissue in tomato, while none were present in the case of potato. Plasmodesmata were present between phloem parenchyma and the phloem sieve tubes in infected tomato but none were present in infected potato. There were pronounced plasmodesmal changes in response to infection in tomato. These included dissolution of the desmotubule (central rod-like structure), making the plasmodesmata pore-like structures with a diameter of ca. 45 nm, which contained electron-dense material, presumably ribonucleoprotein of the virus. No such changes were found in infected potato. These results of comparative studies suggested that the virus was non-systemic in potato due to its non-loading into the phloem and consequently lacked long distance transport.

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 Testing the Münch hypothesis of long distance phloem transport in plants

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Michael Knoblauch ◽  
Jan Knoblauch ◽  
Daniel L Mullendore ◽  
Jessica A Savage ◽  
Benjamin A Babst ◽  
...  
Keyword(s):  
Strong Support ◽  
Sieve Tube ◽  
Phloem Transport ◽  
Plant Tissues ◽  
Long Distance ◽  
Pressure Flow ◽  
Long Distance Transport ◽  
Sieve Tubes ◽  
Distance Transport ◽  
Source And Sink

Long distance transport in plants occurs in sieve tubes of the phloem. The pressure flow hypothesis introduced by Ernst Münch in 1930 describes a mechanism of osmotically generated pressure differentials that are supposed to drive the movement of sugars and other solutes in the phloem, but this hypothesis has long faced major challenges. The key issue is whether the conductance of sieve tubes, including sieve plate pores, is sufficient to allow pressure flow. We show that with increasing distance between source and sink, sieve tube conductivity and turgor increases dramatically in Ipomoea nil. Our results provide strong support for the Münch hypothesis, while providing new tools for the investigation of one of the least understood plant tissues.

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.

scholarly journals OBERON3 and SUPPRESSOR OF MAX2 1-LIKE proteins form a regulatory module specifying phloem identity

2019 ◽  
Author(s):  
Eva-Sophie Wallner ◽  
Nina Tonn ◽  
Friederike Wanke ◽  
Vadir Lopéz-Salmerón ◽  
Michael Gebert ◽  
...  
Keyword(s):  
Stem Cells ◽  
Plant Performance ◽  
Long Distance ◽  
Phloem Tissue ◽  
Phd Finger ◽  
Developmental Program ◽  
Long Distance Transport ◽  
Regulatory Module ◽  
A Cell ◽  
Distance Transport

AbstractThe phloem tissue mediates long-distance transport of energy metabolites along plant bodies and, therefore, is central for plant performance. However, mechanisms initiating the transition of undifferentiated stem cells to cells specialized in metabolite transport are unknown. Here we identify the ubiquitously expressed PHD-finger protein OBERON3 (OBE3) to be essential for phloem formation. We show that OBE3 directly interacts with the SUPPRESSOR OF MAX2 1-LIKE 5 (SMXL5) protein specifically expressed during early phloem development. Both proteins co-localize in nuclei of phloem stem cells and, together with the SMXL5 homologs SMXL3 and SMXL4, promote the establishment of phloem-specific cellular signatures in a cell-autonomous manner. These signatures include expression of OCTOPUS (OPS), BREVIS RADIX (BRX), BARELY ANY MERISTEM3 (BAM3), and COTYLEDON VASCULAR PATTERN2 (CVP2) genes acting as mediators of phloem differentiation. Consistently, genetic analyses show that SMXL5 acts upstream and independently of OPS and BRX functions. Based on our findings, we conclude that the formation of an OBE3/SMXL5 protein complex specifically in nuclei of early phloem cells is essential for establishing a phloem-specific developmental program.

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.

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