Ontogeny of cambium and Phloem in the Epicotyl of Pisum sativum

1968 ◽  
Vol 16 (3) ◽  
pp. 419 ◽  
Author(s):  
S Zee
Keyword(s):  
General Pattern ◽  
Transitional Cell ◽  
Parenchyma Cell ◽  
Sieve Element ◽  
Companion Cell ◽  
Secondary Phloem ◽  
Initial Cell ◽  
Phloem Parenchyma ◽  
Sieve Cell ◽  
Phloem Parenchyma Cell

The pattern of distribution and differentiation of the primary phloem, the cambium, and the secondary phloem, and the exact pattern of division of the initial cell and its derivatives have been studied in the epicotyl of pea plants by using electron microscopy. Three divisional patterns of the initial cell, in giving rise to the phloem cells, are recognized. The initial cell first divides periclinally to give rise to a transitional cell. This transitional cell then divides further (periclinally and/or anticlinally) to give rise to three sequences of phloem derivatives: (1) phloem parenchyma cells, (2) a companion cell and a sieve cell, and (3) a companion cell, a sieve cell, and a phloem parenchyma cell. The derived cells can all easily be distinguished from each other either by their position in the vascular bundle at low magnification or by the different types of plastids present in them. The general pattern of differentiation of the cytoplasm and the formation of the sieve plate and the sieve pores of the sieve element are essentially similar in the primary and the secondary phloem. However, the sieve element of the secondary phloem, unlike that of the primary phloem, possesses in its cytoplasm three kinds of inclusion bodies - an amorphous form, a "crystalline" form, and a tubular form; these are described and their nature discussed.

Development and Dispersal of P-Protein in the Phloem of Coleus Blumei Benth

1969 ◽  
Vol 4 (1) ◽  
pp. 155-169
Author(s):  
M. W. STEER ◽  
E. H. NEWCOMB
Keyword(s):  
Osmium Tetroxide ◽  
Close Association ◽  
Parenchyma Cell ◽  
Protein Body ◽  
Sieve Element ◽  
Phloem Parenchyma ◽  
Coleus Blumei ◽  
P Protein ◽  
Longitudinal View ◽  
Phloem Parenchyma Cell

The development of P-protein (slime) in the phloem of Coleus stem apices has been studied electron microscopically using material fixed in glutaraldehyde followed by osmium tetroxide. In phloem parenchyma cells the earliest-appearing groups of tubular P-protein commonly are seen as close association with clusters of ‘spiny’ vesicles similar to those reported in Phaseolus phloem (Newcomb, 1967). The vesicles break down as the P-protein masses enlarge, and are assumed to contribute to P-protein formation. Subsequently the groups of tubules are consolidated into a single spindle-shaped body aligned longitudinally in each phloem parenchyma cell or sieve element. The microtubules observed frequently in the vicinity of the young P-protein body may play a role in its consolidation or in the longitudinal alignment of its constituent tubules. Some P-protein bodies acquire a highly organized structure in which the tubules are arranged hexagonally around lightly staining centres. Disaggregation of the P-protein body occurs during disintegration of the cytoplasm and nucleus, and results initially in the presence of swirls of packed fibrils. During disaggregation, the tubules of the mature P-protein body, which are about 200 Å in diameter, are converted to fibrils about 70 Å in diameter in a process apparently with several intermediate stages. In longitudinal view the fibrils exhibit alternate electron transparent and dense bands that impart a striated appearance to the mass. During maturation of the sieve element the swirls of fibrillar masses separate into individual fibrils which become dispersed through the cell lumen.

Fine structure of the phloem of Pisum sativum. II. The companion cell and phloem parenchyma

1965 ◽  
Vol 13 (2) ◽  
pp. 185
Author(s):  
MC Wark
Keyword(s):  
Fine Structure ◽  
Sieve Element ◽  
Companion Cell ◽  
Secondary Phloem ◽  
Sieve Elements ◽  
Phloem Parenchyma ◽  
Wall Structures ◽  
Companion Cells ◽  
Parenchyma Cells ◽  
Vacuolated Cells

The companion cells of the secondary phloem of Pisum contain all the organelles characteristic of cells possessing an active metabolism. The cytoplasm of the companion cells shows little change during ontogeny. Complex plasmodesmata connect the sieve elements and companion cells. These are the only connections observed between the sieve elements and other phloem cells. New wall structures of the companion cells are described. These structures are here tentatively called trabeculae; they intrude into the cytoplasm, but never completely cross the cell. The trabeculae alter in appearance at the time when the sieve element nucleus and tonoplast disappear. The phloem parenchyma cells are large vacuolated cells wider in diameter but shorter in length than the sieve elements. They contain all the organelles found in normal photosynthetic tissue. The cytoplasm of the phloem parenchyma shows little change during ontogeny. Plasmodesmata of well-developed pit fields connect the phloem parenchyma with the companion cells. The phloem parenchyma does not communicate with the sieve elements.

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.

scholarly journals Cellular and Metabolite Changes in the Secondary Phloem of Chinese Fir (Cuninghamia lanceolata (Lamb.) Hook.) during Dormancy Release

Forests ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1552
Author(s):  
Jiangtao Shi ◽  
Chongyang Xia ◽  
Junyi Peng ◽  
Xing Liu ◽  
Biao Pan
Keyword(s):  
Chinese Fir ◽  
Dormancy Release ◽  
Secondary Phloem ◽  
Phloem Tissue ◽  
Dormant Period ◽  
Phloem Parenchyma ◽  
Sieve Cells ◽  
Sieve Cell ◽  
Before And After ◽  
Cambium Zone

Wood in the cold temperate zone is the product of the alternation of the growing season and the dormant period of trees, but our knowledge of the process of dormancy release in trees remains limited. Chinese fir (Cuninghamia lanceolata (Lamb.) Hook.) was used to investigate cellular and metabolite changes in the secondary phloem tissue during dormancy release. The sampling dates were 2 March, 28 March, and 13 April. The microsections of wood-forming tissue were prepared using the paraffin embedding technique to observe the formation of cambium cells; metabolites in secondary phloem cells were extracted using a methanol/chloroform organic solvent system. The results showed that the secondary phloem consists of phloem fibers, sieve cells and phloem parenchyma. The cells were regularly arranged in continuous tangential bands and were in the order of Phloem fiber-Sieve cell-Phloem parenchyma-Sieve cell-Phloem parenchyma-Sieve cell-Phloem parenchyma-Sieve cell-Sieve cell-Phloem parenchyma-. The Chinese fir cambium was in dormancy on 2 March and 28 March, while on 13 April, it was already in the active stage and two layers of xylem cells with several layers of phloem cells were newly formed. The width of the cambium zone increased from 18.7 ± 5.7 μm to 76.5 ± 3.0 μm and the average radial diameter of sieve cells expanded from 15.4 ± 7.5 μm to 21.5 ± 7.4 μm after dormancy release. The cambium zone width and the average radial diameter of sieve cells before and after dormancy release were significantly different (p < 0.01). The phloem parenchyma cells without resin were squeezed and deformed by the sieve cells, and the width of the phloem during the active period was 197.0 ± 8.5 μm, which was larger than that during the dormant period. Ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS)-based metabolomics was employed to analyze the secondary phloem of Chinese fir on 28 March and 13 April. Thirty-nine differential metabolites during dormancy release were detected. The results showed that the composition of Chinese fir metabolites was different before and after dormancy release. The relative increase in pyruvic acid and ascorbic acid contents proved that the rate of energy metabolism in Chinese fir increased substantially after dormancy release. Changes in cell development and the composition of metabolites revealed that the dormancy release of Chinese fir was at early April and the formation period of phloem tissue is earlier than xylem tissue.

Development of the secondary phloem of the primary root of Pisum

1969 ◽  
Vol 17 (2) ◽  
pp. 199 ◽  
Author(s):  
S Zee ◽  
TC Chambers
Keyword(s):  
Fine Structure ◽  
Rna Synthesis ◽  
Early Stage ◽  
Primary Root ◽  
Sieve Element ◽  
Secondary Phloem ◽  
Uridine Incorporation ◽  
Phloem Parenchyma ◽  
Stage Of Development ◽  
Chromatin Material

The divisional pattern of the cambium in giving rise to the secondary phloem and the associated changes in the fine structure of the cellular components from the initial to the morphologically mature sieve element have been described. The fine structure of the sieve element plastid is of particular interest in that it lacks a well-developed internal membrane system but contains two characteristic inclusion bodies, starch granules (which often break up into smaller units) and protein crystalloids (which invariably show subunits with either one- or two-directional periodicity). Electron microscope autoradiographs were made of cambial cells and their phloem derivatives in tissues exposed either to [3H]thymidine for 24 hr (followed by growth in the absence of tracer for 4 days) or to [3H]uridine for 2-12 hr without a further growth period. The [3H]thymidine labels were specifically lodged in the chromatin material of the cambial initials, the companion cells, the phloem parenchyma cells, and the young sieve elements. During sieve element maturation the [3H]thymidine label became less specifically associated with the chromatin material. The pattern of labelling of the [3H]uridine in addition to being associated with the nucleolus was also associated with the chromatin, the electron-lucent areas of the nucleus, and the cytoplasm of the young sieve element, the companion cell and the phloem parenchyma indicating that these cells were all active in RNA synthesis. In the sieve element the nucleolus disappeared at a very early stage of development. This was associated with a decrease in [3H]uridine incorporation into the nucleus. As the tonoplast of the sieve element disintegrated, [3H]uridine incorporation into both the nucleus and the cytoplasm stopped, which is interpreted as a cessation in RNA synthesis. At no stage in the development of the sieve element was [3H]uridine incorporated into the "slime" material.

Anatomy of the Secondary Phloem in Winteraceae

IAWA Journal ◽  
1984 ◽  
Vol 5 (1) ◽  
pp. 13-43 ◽  
Author(s):  
Katherine Esau ◽  
Vernon I. Cheadle
Keyword(s):  
Protein Body ◽  
Sieve Element ◽  
Secondary Phloem ◽  
Phloem Parenchyma ◽  
The Family ◽  
Companion Cells ◽  
Parenchyma Cells ◽  
Evolutionary Level ◽  
Fusiform Initials ◽  
Sieve Plates

The secondary phloem of nine species in five genera of Winteraceae was examined with regard to features that could serve for taxonomic and phylogenetic evaluation of the family. The species examined were as follows: Bubbia pauciflora, B. semecarpoides, Drimys lanceolata, D. winteri, Exospermum stipitatum, Pseudo wintera axillaris, Zygogynum baillonii, Z. bicolor, and Z. vinkii. The nine species showed the following common characteristics: 1) origin from nonstoried vascular cambium with long fusiform initials; 2) ray system consisting of high multiseriate and high uniseriate rays; 3) occurrence of secondary partitioning in the differentiating phloem so that the sieve elements are much shorter than the tracheids; 4) lack of sharp differentiation between lateral sieve areas and those of the sieve plates; 5) predominance of compound sieve plates; 6) short companion cells, often single in a given sieve element; 7) phloem parenchyma cells in strands; 8) lack of specialised fibres (bast fibres) in the secondary phloem; 9) presence of nondispersing protein body in the sieve element protoplast. Features numbered 1, 2, 4-6 are considered to be indications of low evolutionary level. The significance of the other three features (3, 7-9) requires further evaluation. Among these three is the secondary partitioning the occurrence of which seems to imply that in some taxa the well known sequence of evolutionary shortening of cambial initials and their derivatives may be accelerated on the phloem side.

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.

Early modifications of the internodal anatomy of Glycine max sprayed with 2,4-DB

1979 ◽  
Vol 57 (12) ◽  
pp. 1340-1344 ◽  
Author(s):  
Thompson Demetrio Pizzolato ◽  
David L. Regehr
Keyword(s):  
Cell Division ◽  
Cell Enlargement ◽  
Secondary Phloem ◽  
Anatomical Changes ◽  
Phloem Parenchyma ◽  
Cortical Parenchyma ◽  
Parenchyma Cells ◽  
Radial Cell ◽  
Orderly Fashion ◽  
Stimulation Of

An aqueous spray of 4-(2,4-dichlorophenoxy)butyric acid (2,4-DB) induces anatomical changes in young Glycine internodes. Four days after spraying, the first symptoms appear outside the cambium when the interfascicular parenchyma cells and the adjacent cortical parenchyma cells enlarge and divide in several planes. Four days later, the metaphloem parenchyma cells in many of the leaf traces undergo considerable periclinal cell division and extensive radial cell enlargement. The phloem parenchyma cells of the late metaphloem and first secondary phloem enlarge and divide in a less orderly fashion. Fifteen days after treatment, the cortical parenchyma is modified into a band of radially seriate cells above the protophloem fibers. Products of this cambium-like region convert the cortex into a callus-like tissue. The size of starch grains is reduced initially in the phloem and xylem and later in the cortex. It appears that the stimuli produced by 2,4-DB move into the internode via the metaphloem of leaf traces. Despite the rapid obliteration of conducting phloem by the 2,4-DB induced stimulation of phloem parenchyma, an accelerated differentiation of secondary phloem compensates for this loss.

DISTRIBUTION OF VEGETATIVE STORAGE PROTEINS IN ROSACEAE

IAWA Journal ◽  
2003 ◽  
Vol 24 (4) ◽  
pp. 421-428
Author(s):  
Wei-Min Tian ◽  
Zheng-Hai Hu
Keyword(s):  
Seasonal Changes ◽  
Storage Proteins ◽  
Protein Body ◽  
Diagnostic Feature ◽  
Secondary Phloem ◽  
Apple Trees ◽  
Phloem Parenchyma ◽  
Vegetative Storage Proteins ◽  
Parenchyma Cells ◽  
First Time

The distribution pattern of vegetative storage proteins is reported for the first time for 18 species and 2 varieties of twelve genera of Rosaceae. Vegetative storage proteins were present in all the species studied of Prunoideae and absent in Maloideae. Their occurrence in a genus seemed to be either universal or entirely absent. Rosaceae trees were poor in vegetative storage proteins and the form of vegetative storage proteins was not protein body-like. Granular and floccular forms of vegetative storage proteins could be distinguished exclusively in the secondary phloem parenchyma cells and their distribution was cell-specific. Our results suggest that the distribution of vegetative storage proteins in Rosaceae can be considered as a taxonomically diagnostic feature. The nature of the bark proteins with seasonal changes in apple trees is discussed.

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