scholarly journals Nonparallelism of cambium cells in neighboring rows

2014 ◽  
Vol 50 (4) ◽  
pp. 625-636 ◽  
Author(s):  
Wiesław Włoch
Keyword(s):  
Radial Growth ◽  
Longitudinal Direction ◽  
Intrusive Growth ◽  
Continuous Layer ◽  
Mutual Contact ◽  
Cambial Cells ◽  
Periclinal Walls ◽  
Network Pattern

The periclinal walls of cambial cells in neighboring lineages (rows) may not be parallel when viewed in their radial aspect. This lack of longitudinal parallelism may be so extensive that in active cambium pairs of cells from neighboring rows may be in contact only along restricted segments. This means that the initial cells, rather than farming a continuous layer, may be arranged in an irregular network pattern from which some parts project inward or outward from the layer of their mutual cantacts. The longitudinal nonparallelism of cambial cells becomes more pronounced during symplasitic radial growth. Unequal periclinal divisions counteract this, and in initial cells abscission of the parts projecting from the layer of mutual contact occurs. When the cambium passes from a period of activity to a Period of rest a continuous layer of initials is reestabhshed. This involves elongation by intrusive growth of those cells previously shortened as the result of irregular periclinal divisions. The division walls in cambial cells may be warped, that is they change their orientation along the longitudinal direction perhaps even similar to an aircraft propeller. A division wall may thus be periclinal in one part of the cell and anticlinal in another.

scholarly journals How Do Trees Grow in Girth? Controversy on the Role of Cellular Events in the Vascular Cambium

2021 ◽  
Author(s):  
Anna Wilczek-Ponce ◽  
Wiesław Włoch ◽  
Muhammad Iqbal
Keyword(s):  
Woody Plants ◽  
Radial Growth ◽  
Apical Cell ◽  
Vascular Cambium ◽  
Cell Dynamics ◽  
Cellular Events ◽  
New Concepts ◽  
New Interpretation ◽  
Cambial Cells ◽  
Periclinal Walls

AbstractRadial growth has long been a subject of interest in tree biology research. Recent studies have brought a significant change in the understanding of some basic processes characteristic to the vascular cambium, a meristem that produces secondary vascular tissues (phloem and xylem) in woody plants. A new hypothesis regarding the mechanism of intrusive growth of the cambial initials, which has been ratified by studies of the arrangement of cambial cells, negates the influence of this apical cell growth on the expansion of the cambial circumference. Instead, it suggests that the tip of the elongating cambial initial intrudes between the tangential (periclinal) walls, rather than the radial (anticlinal) walls, of the initial(s) and its(their) derivative(s) lying ahead of the elongating cell tip. The new concept also explains the hitherto obscure mechanism of the cell event called ‘elimination of initials’. This article evaluates these new concepts of the cambial cell dynamics and offers a new interpretation for some curious events occurring in the cambial meristem in relation to the radial growth in woody plants.

Apical intrusive growth of cambial fusiform initials along the tangential walls of adjacent fusiform initials: evidence for a new concept

2006 ◽  
Vol 54 (5) ◽  
pp. 493 ◽  
Author(s):  
Joanna Jura ◽  
Paweł Kojs ◽  
Muhammad Iqbal ◽  
Joanna Szymanowska-Pułka ◽  
Wiesław Włoch
Keyword(s):  
Cell Walls ◽  
Tilia Cordata ◽  
Intrusive Growth ◽  
Radial Wall ◽  
Cambial Cell ◽  
Fusiform Initials ◽  
Periclinal Walls ◽  
Symplastic Growth ◽  
Wisteria Floribunda ◽  
Fusiform Initial

A new study of cambium of Pinus sylvestris L., Tilia cordata Mill. and Wisteria floribunda (Willd.) DC provides fresh clues on the cambial dynamics, rejecting the hitherto held concept that intrusive growth of the fusiform initial occurs between the radial walls of adjacent initials. It demonstrates that intrusion of the elongating initial in fact takes place along tangential walls of adjacent fusiform initials and their immediate derivatives. It also suggests a new mechanism for ‘elimination of initials’. Intrusive growth of the fusiform initial was found to begin with development of characteristic slants, representing a transitional stage of the process of transformation of periclinal walls of fusiform initial cells into radial walls, as observed in transverse sections of active cambium. The gradually progressing event comprised (a) appearance of either a triangular microspace limited by two periclinal walls of a fusiform initial and its derivative and one radial wall of another fusiform initial in the adjacent radial file, or a rhomboidal microspace enclosed by four periclinal walls of two laterally adjacent fusiform initials and their immediate derivatives, (b) intrusion of elongating tip of fusiform initial from neighbouring file into the microspace thus formed, (c) symplastic growth of the cambial cell walls in radial direction, (d) unequal periclinal divisions of fusiform initial cells while growing intrusively, and (e) unequal periclinal divisions of derivative cells not growing intrusively. Intrusive growth between periclinal walls affected rearrangement of the fusiform initials but did not add to the cambial circumference. The existing concepts of (a) intrusion of the fusiform initial between radial walls of neighbouring initials and (b) elimination of fusiform initials from cambial surface have been reassessed and redefined.

Mathematical Modeling of Intrusive Growth of Fusiform Initials in Relation to Radial Growth and Expanding Cambial Circumference in Pinus sylvestris L.

2009 ◽  
Vol 57 (3) ◽  
pp. 331-348 ◽  
Author(s):  
D. Karczewska ◽  
J. Karczewski ◽  
W. Włoch ◽  
J. Jura-Morawiec ◽  
P. Kojs ◽  
...  
Keyword(s):  
Mathematical Modeling ◽  
Pinus Sylvestris ◽  
Radial Growth ◽  
Intrusive Growth ◽  
Fusiform Initials

Correlation of intrusive growth of cambial initials to rearrangement of rays in the vascular cambium

IAWA Journal ◽  
2011 ◽  
Vol 32 (3) ◽  
pp. 313-331 ◽  
Author(s):  
Anna Wilczek ◽  
Joanna Jura-Morawiec ◽  
Paweł Kojs ◽  
Muhammad Iqbal ◽  
Wiesław Włoch
Keyword(s):  
Pinus Sylvestris ◽  
Vascular Cambium ◽  
Tilia Cordata ◽  
Intrusive Growth ◽  
Hippophaë Rhamnoides ◽  
Fusiform Initials ◽  
Cambial Cells ◽  
The One ◽  
Fusiform Initial ◽  
Ray Initials

It is well documented that apical elongation of fusiform cambial initials through extension of their longitudinal edges, and their intrusion between tangential walls of the neighbouring initials and their closest derivatives cause rearrangement of fusiform cells, without increasing the cambial circumference. However, the concurrent rearrangement of rays is not fully understood. This study deals with Pinus sylvestris L., Tilia cordata Mill. and Hippophaë rhamnoides L., possessing a nonstoreyed, storeyed and double-storeyed type of cambium, respectively, and shows that the mechanism for rearrangement of ray initials is similar to the one proposed for fusiform initials, and includes multiplication of ray initials by anticlinal divisions, intrusive growth of ray initials, elimination of ray initials caused by intrusive growth of neighbouring fusiform initials, and transformation of ray initials into fusiform initials. Intrusive growth of a ray initial does not necessarily lead to the formation of a new fusiform initial, as it is dependent on the extent of the intrusive growth taken place. The extent of rearrangement of cambial cells is determined by the intensity of events occurring among the fusiform as well as ray initials. Intrusive growth of these initials does not influence the size of the cambial circumference.

Cambial Development and Tracheid Length of Dwarf Pines (Pinus Densiflora and P. Thunbergii)

IAWA Journal ◽  
1997 ◽  
Vol 18 (3) ◽  
pp. 301-310 ◽  
Author(s):  
Dong Ok Lim ◽  
Woong Young Soh
Keyword(s):  
Pinus Densiflora ◽  
Annual Rings ◽  
Intrusive Growth ◽  
Tracheid Length ◽  
Naturally Occurring ◽  
Anticlinal Division ◽  
Fusiform Initials ◽  
Cambial Cells ◽  
Mother Cells

From a comparison of cambial cells and their derivatives between naturally occurring dwarf trees and normal ones, it was concluded that tracheids in the annual rings of dwarf trees are shorter, narrower and fewer than those of normal trees. The frequency of anticlinal division and loss of cambial initials is low during differentiation of xylem cells from cambial initials in dwarf pines. The length and intrusive growth of fusiform initials are slightly less than those of normal trees. Thus, it is concluded that the shortening of tracheids in dwarf trees is due to the fact that cambial initials are themselves shortened and that intrusive growth during differentiation of xylem mother cells has occurred.

scholarly journals The Impact of Changing Climate on the Cambial Activity during Radial Growth in Some Citrus Species

2021 ◽  
Author(s):  
Moin Ahmad Khan ◽  
M. Badruzzaman Siddiqui
Keyword(s):  
Radial Growth ◽  
Cambial Activity ◽  
Age Effects ◽  
Vascular Cambium ◽  
Citrus Species ◽  
The Third ◽  
Changing Climate ◽  
Fusiform Initials ◽  
Cambial Cells ◽  
The Impact

This study on radial growth in the stem of Citrus was carried out with an aim to notice the behavior of vascular cambium with respect to climatic and age effects. The fusiform initials vary in length from 137 to 363 μm in C. limon, 100 to 463 μm in C. paradisi, 137 to 413 μm in C. reticulata var. kinnow, and 137 to 375 μm in C. sinensis. The length rises with age, followed by decline and then again increase in C. limon. In C. paradisi, there is increase up to maximum and after decline is soon followed by constancy. In C. reticulata var. kinnow, increase in length from top to base in C. sinensis, increase up to maximum followed by a decline. Swelling of cambial cells occurs in the third week of March in C. limon, last week of March in C. paradisi, third week of April in C. reticulata var. kinnow, and second week of April in C. sinensis. The cambium turns dormant in early October in C. limon, late December in C. paradisi, early December in C. reticulata var. kinnow, and early November in C. sinensis. Thus, the cambium remains active for about 6 months in C. limon and C. sinensis, 9 months in C. paradisi, and 7 months in C. reticulata var. kinnow.

THE RATE OF ELONGATION OF FUSIFORM INITIALS IN THE CAMBIUM OF PINACEAE

1965 ◽  
Vol 43 (4) ◽  
pp. 429-435 ◽  
Author(s):  
M. W. Bannan
Keyword(s):  
Cell Elongation ◽  
Radial Growth ◽  
Ring Width ◽  
Total Width ◽  
Mature Trees ◽  
Cambial Cell ◽  
Anticlinal Division ◽  
Fusiform Initials ◽  
Wide Ring ◽  
Cambial Cells

This report deals with the rate and amount of elongation of fusiform initials in the cycle of cell elongation and multiplication by pseudotransverse division which accompanies circumferential expansion of the cambium. In the recent growth of mature trees the yearly amount of cambial cell elongation drops as ring width decreases, but not in proportion to the decline in ring width. The cumulative elongation through lineal series of cells, per centimeter of xylem increment, increases as ring width decreases. The amount of cell elongation during the production of several narrow rings greatly exceeds that through a single wide ring having the same total width. It seems clear that the time factor is important in the elongation of cambial cells, and to some extent the interrelated frequency of anticlinal division, particularly when radial growth declines.

Surface Films on Zircaloy-2 Samples Cracked in Neutral Aqueous NaCl by Stress Corrosion

1973 ◽  
Vol 31 ◽  
pp. 46-47
Author(s):  
R.A. Ploc
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Film Thickness ◽  
Stress Corrosion ◽  
Zirconium Dioxide ◽  
Surface Film ◽  
Surface Films ◽  
Continuous Layer ◽  
Transmission Electron ◽  
Product Film

Samples of low-nickel Zircaloy-2 (material MLI-788-see(1)), when anodically polarized in neutral 5 wt% NaCl solutions, were found to be susceptible to pitting and stress corrosion cracking. The SEM revealed that pitting of stressed samples was occurring below a 2000Å thick surface film which behaved differently from normal zirconium dioxide in that it did not display interference colours. Since the initial film thickness was approximately 65Å, attempts were made to examine the product film by transmission electron microscopy to deduce composition and how the corrosion environment could penetrate the continuous layer.

Behavior of contact-silicided TFSOI gate structures

1994 ◽  
Vol 52 ◽  
pp. 860-861
Author(s):  
N. David Theodore ◽  
Juergen Foerstner ◽  
Peter Fejes
Keyword(s):  
Semiconductor Device ◽  
Series Resistance ◽  
Field Effect Transistors ◽  
Silicon Layer ◽  
Device Fabrication ◽  
Silicon On Insulator ◽  
Continuous Layer ◽  
Buried Oxide ◽  
Device Structures ◽  
Thin Silicon

As semiconductor device dimensions shrink and packing-densities rise, issues of parasitic capacitance and circuit speed become increasingly important. The use of thin-film silicon-on-insulator (TFSOI) substrates for device fabrication is being explored in order to increase switching speeds. One version of TFSOI being explored for device fabrication is SIMOX (Silicon-separation by Implanted OXygen).A buried oxide layer is created by highdose oxygen implantation into silicon wafers followed by annealing to cause coalescence of oxide regions into a continuous layer. A thin silicon layer remains above the buried oxide (~220 nm Si after additional thinning). Device structures can now be fabricated upon this thin silicon layer.Current fabrication of metal-oxidesemiconductor field-effect transistors (MOSFETs) requires formation of a polysilicon/oxide gate between source and drain regions. Contact to the source/drain and gate regions is typically made by use of TiSi2 layers followedby Al(Cu) metal lines. TiSi2 has a relatively low contact resistance and reduces the series resistance of both source/drain as well as gate regions

Mutuality in Acculturation

2013 ◽  
Vol 221 (4) ◽  
pp. 205-213 ◽  
Author(s):  
Gabriel Horenczyk ◽  
Inga Jasinskaja-Lahti ◽  
David L. Sam ◽  
Paul Vedder
Keyword(s):  
Intergroup Relations ◽  
Extended Model ◽  
Psychological Study ◽  
Intergroup Interactions ◽  
Mutual Contact ◽  
Acculturation Model ◽  
Plural Societies ◽  
Perceptions And Expectations

This paper focuses on processes and consequences of intergroup interactions in plural societies, focusing primarily on majority-minority mutuality in acculturation orientations. We examine commonalities and differences among conceptualizations and models addressing issues of mutuality. Our review includes the mutual acculturation model ( Berry, 1997 ), the Interactive Acculturation Model (IAM – Bourhis et al., 1997 ), the Concordance Model of Acculturation (CMA – Piontkowski et al., 2002 ); the Relative Acculturation Extended Model (RAEM – Navas et al., 2005 ), and the work on acculturation discrepancies conducted by Horenczyk (1996 , 2000 ). We also describe a trend toward convergence of acculturation research and the socio-psychological study of intergroup relations addressing issues of mutuality in attitudes, perceptions, and expectations. Our review has the potential to enrich the conceptual and methodological toolbox needed for understanding and investigating acculturation in complex modern societies, where majorities and minorities, immigrants and nationals, are engaged in continuous mutual contact and interaction, affecting each other’s acculturative choices and acculturative expectations.

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