Structural Aspects of the Pathways of Nutrient Flow to the Developing Embryo and Cotyledons of Pisum sativum L

1976 ◽  
Vol 24 (6) ◽  
pp. 711 ◽  
Author(s):  
AR Hardham
Keyword(s):  
Vascular Tissue ◽  
Embryo Sac ◽  
Phloem Tissue ◽  
Sieve Elements ◽  
Boundary Wall ◽  
Surface Areas ◽  
Pisum Sativum L ◽  
Large Numbers ◽  
Pea Seed ◽  
Structural Aspects

The pea seed requires large quantities of nutrient during its growth and development. In the early stages a large proportion of this nutrient is obtained from the endosperm surrounding the embryo in the embryo sac. A number of structural specializations, such as increased surface areas of the embryo sac boundary wall and the extra-embryonic wall and breakdown of the inner ovular cells, may aid in the passage of nutrient to the developing embryo. This study has shown that the amount of vascular tissue in the funicle and ovule increases markedly between the time of cotyledon initiation and the commencement of storage protein synthesis and deposition. Large numbers of transfer cells are associated with the sieve elements in the pod and funicle, but not in the ovule. Also, the numbers of xylem and sieve elements in the funicle decrease as the strand passes from the pod to the ovule. Two strands of phloem tissue were found to branch from the main vascular bundle in the ovule and to sweep across the base of the seed and around either side of the narrow tubular arm of the embryo sac which contains the radicle.

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.

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.

The Influence of Structural Aspects of the English Counting Word System on the Teaching and Learning of Place Value

1998 ◽  
Vol 59 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Ian Thompson
Keyword(s):  
Young Children ◽  
Teaching And Learning ◽  
Place Value ◽  
Single Digit ◽  
Value System ◽  
Number Words ◽  
Large Numbers ◽  
Structural Aspects

The influence of structural aspects of the English counting word system on the teaching and learning of place value In their discussion of the teaching of place value to young children Fuson and Briars (1990) describe the extent to which the English spoken system of number words constitutes a ‘named value’ system for large numbers. They argue that, because two-digit numbers are not ‘named value’, teachers should move from teaching single-digit calculations to teaching calculations with large numbers, only returning to two-digit numbers when children are familiar with the standard written algorithms. This article uses transcriptions of children calculating mentally to suggest that they appear to take advantage of the ‘partitionable’ aspect of the language associated with two-digit numbers - an aspect that Fuson and Briars (1990) appear to have ignored. These examples appear to raise questions about their recommendation that teachers should progress from single-digit to large number calculations.

The morphology of grain abscission in Zizania aquatica

1980 ◽  
Vol 58 (21) ◽  
pp. 2269-2273 ◽  
Author(s):  
H. B. Hanten ◽  
G. E. Ahlgren ◽  
J. B. Carlson
Keyword(s):  
Wild Rice ◽  
Cell Walls ◽  
Vascular Tissue ◽  
Embryo Sac ◽  
Middle Lamella ◽  
Abscission Zone ◽  
Rice Grains ◽  
Zizania Aquatica ◽  
Parenchyma Cells ◽  
Anatomical Evidence

The anatomical development of the abscission zone in grains of Zizania aquatica L. was correlated with development of the embryo. The abscission zone is well developed when the embryo sac is mature. Soon after pollination, the first anatomical evidence of abscission appears as plasmolysis of the separation layer parenchyma cells. This is followed by separation of the layers by dissolution of the middle lamella and fragmentation of cell walls. Persistence of intact vascular tissue and presence of a surrounding cone-shaped mass of lignified cells may be involved in abscission of wild rice grains.

scholarly journals Reduction in the content of antinutritional substances in pea seeds (Pisum sativum L.) by different treatments

2011 ◽  
Vol 50 (No. 11) ◽  
pp. 519-527 ◽  
Author(s):  
R. Dvořák ◽  
A. Pechová ◽  
L. Pavlata ◽  
J. Filípek ◽  
J. Dostálová ◽  
...  
Keyword(s):  
Pisum Sativum ◽  
Seed Treatment ◽  
Production Traits ◽  
Pisum Sativum L ◽  
Heat Treated ◽  
Pea Seeds ◽  
Reactor Temperature ◽  
Pre Treatment ◽  
Pea Seed ◽  
Representative Samples

The goal of the trial was to reduce the content of antinutritional substances in pea (Pisum sativum L.) seeds in order to enhance its use in livestock nutrition. A variety of field pea (Pisum sativum L.) with a high content of antinutritional substances and favourable production traits (Gotik) was chosen. Native and heat-treated pea seeds were used to collect representative samples (n = 6) for analytical purposes. The technology (V-0 technology, Czech patent No. 285745) was further modified by adjusting the reactor temperature, the duration of exposure to that temperature, and the duration of ageing of the material treated in this way (V-I and V-II technologies). The methodology of treatment is based on exposing pea seeds to vapour, organic acids and selected oxides.The monitored parameters included antinutritional substances. As far as the antinutritional substances were concerned, the content of trypsin inhibitors in native pea seeds (P) was around 15.4 ± 0.5 TIU. After treatment with technologies V-0, V-I, and V-II its activity dropped by 83.8, 80.5 and 83.8%, respectively. The pre-treatment titre of lectins (P) was 717 ± 376. It dropped by 70.3, 35.7 and 73.2% after treatment with technologies V-0, V-I and V-II, respectively. The content of tannins measured by the amount of gallic acid in native pea seeds was 49.1 ± 2.7 mg per kg. It dropped by 41.4, 32.0 and 46.2% after the application of the above-mentioned technologies. The content of indigestible oligosaccharides causing flatulence was less affected by the treatments. The pre-treatment content of raffinose was 9.5 ± 0.5 g/kg. The drop associated with the treatment was 9.5, 6.3 and 10.5%, respectively. The pre-treatment content of stachyose was 21.4 ± 0.8 g/kg and after treatment with technologies V-0 and V-II it dropped by 7.0% and by 16.4%, respectively. The application of technology V-I did not result in a drop in the content of stachyose. The content of verbascose in native pea seeds was 16.1 g/kgand the treatment with technologies V-0; V-I and V-II resulted in a drop by 7.5, 5.6 and 20.5%, respectively. As for the detected phenolic acids, with the exception of caffeic acid, not a drop, but an increase in their content was recorded. Isoflavone oestrogens such as daidzein and genistein also recorded a small increase in their content. The results of the trial lead us to conclude that the above-described methods of pea seed treatment, especially the V-II variant, proved to be useful and can be recommended for practical use.  

SCREENING OF FIELD PEA BREEDING LINES FOR PEA SEED-BORNE MOSAIC VIRUS

1979 ◽  
Vol 59 (1) ◽  
pp. 171-175 ◽  
Author(s):  
S. T. ALI-KHAN ◽  
R. C. ZIMMER
Keyword(s):  
Pisum Sativum ◽  
Mosaic Virus ◽  
Field Pea ◽  
Research Station ◽  
Chenopodium Amaranticolor ◽  
Breeding Lines ◽  
Pisum Sativum L ◽  
Local Lesion Host ◽  
Extensive Program ◽  
Pea Seed

Pea seed-borne mosaic virus (PSbMV) was first identified in Canadian field pea (Pisum sativum L.) breeding lines in 1974. Since then, an extensive program has been underway to eradicate this virus from the breeding lines. At the Morden Research Station, nearly 2000 breeding lines were evaluated. The virus was assayed by infectivity tests using the local lesion host Chenopodium amaranticolor, and by a gel immunodiffusion test. PSbMV was detected in 1361 lines. The level of infection within lines varied from 1 to 3%. Due to the restricted extent of the virus in the breeding lines, it was possible to continue the breeding program without a serious loss in germplasm.

Proteomics offers insight to the mechanism behind Pisum sativum L. response to pea seed-borne mosaic virus (PSbMV)

2017 ◽  
Vol 153 ◽  
pp. 78-88 ◽  
Author(s):  
Hana Cerna ◽  
Martin Černý ◽  
Hana Habánová ◽  
Dana Šafářová ◽  
Kifah Abushamsiya ◽  
...  
Keyword(s):  
Pisum Sativum ◽  
Mosaic Virus ◽  
Pisum Sativum L ◽  
Pea Seed

Fine structure of the phloem of Pisum sativum. I. The sieve element ontogeny

1965 ◽  
Vol 13 (2) ◽  
pp. 171 ◽  
Author(s):  
MC Wark ◽  
TC Chambers
Keyword(s):  
Endoplasmic Reticulum ◽  
Pisum Sativum ◽  
Nuclear Material ◽  
Sieve Element ◽  
Secondary Phloem ◽  
Sieve Elements ◽  
Pisum Sativum L ◽  
Ontogenetic Study ◽  
Sieve Plates ◽  
Peripheral Cytoplasm

An ontogenetic study of secondary phloem sieve elements of Pisum sativum L., fixed on the intact plant for electron microscopy, indicates that the connecting strands across the sieve plates are continuities of the endoplasmic reticulum. Each connecting strand is surrounded by a callose cylinder. The peripheral cytoplasm of the nucleate "young" sieve elements contains longitudinally oriented tubules of endoplasmic reticulum. As the sieve elements develop, nuclear material is extruded into the cytoplasm by way of a fibrotubular body which is structurally distinct from the slime body. When the cells are fully expanded the slime bodies disperse. This process is followed by breakdown of a number of organelles including the nucleus and tonoplast. This apparently leaves the endoplasmic reticulum free in the cell lumen.

Fine structure of the primary root phloem of Pisum

1968 ◽  
Vol 16 (1) ◽  
pp. 37 ◽  
Author(s):  
SY Zee ◽  
TC Chambers
Keyword(s):  
Primary Root ◽  
Root Apex ◽  
Sieve Element ◽  
Cross Wall ◽  
Secondary Phloem ◽  
Sieve Elements ◽  
Phloem Parenchyma ◽  
Pisum Sativum L ◽  
Companion Cells ◽  
Stem Internode

The morphogenesis of the sieve elements, companion cells, and phloem parenchyma in the region between 0.5 and 2.0 mm from the actively growing root apex of seedlings of Pisum sativum L. cv. Telephone is described. The overall developmental pattern is essentially similar to that already described for the secondary phloem of the young stem internode of the same species, although differences in the development of some organelles do exist between the two types of phloem. The development of the sieve element is traced from the earliest stages of cross wall formation up to the morphologically mature stages. Very few sieve elements reach morphological maturity in this region. The possibility that the functional translocatory sieve elements are those at earlier stages of development is discussed.

Acid Phosphatase Activities in Developing Seeds of Pisum sativum L

1977 ◽  
Vol 4 (6) ◽  
pp. 843 ◽  
Author(s):  
DR Murray ◽  
MD Collier
Keyword(s):  
Acid Phosphatase ◽  
Pisum Sativum ◽  
Phosphatase Activity ◽  
Cell Expansion ◽  
Acid Phosphatase Activity ◽  
Minor Components ◽  
Ph Optimum ◽  
Pisum Sativum L ◽  
Almost All ◽  
Pea Seed

The seedcoats contain almost all of the acid phosphatase activity (EC 3.1.3.2) in the pea seed in the earliest stages of expansion. The seedcoat activity is maximal by the end of the period of rapid cell expansion and declines as the embryo matures. The developing cotyledons show a later rise in acid phosphatase activity to a maximum shortly before dehydration. The activity in the embryonic axis shows a marked increase only during dehydration. The acid phosphatase activity in the seedcoats results almost entirely from an isoenzyme with high electrophoretic mobility in 5.5% polyacrylamide gels (RF 0.97). This isoenzyme has not been detected in other tissues from the plant. The phosphatase activity in the cotyledons is accounted for by one major isoenzyme at RF 0.75 and by four minor components. The partially purified enzyme from the seedcoats shows a broad pH optimum from pH 5.0 to pH 6.0. In contrast, the preparation from the cotyledons has an optimum close to pH 5.6 and is slightly more sensitive to inhibition by 0.2 mM PI.

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