Microfibrils in primary and secondary wall growth develop trellis configurations

1975 ◽  
Vol 53 (23) ◽  
pp. 2687-2701 ◽  
Author(s):  
J. D. Boyd ◽  
R. C. Foster
Keyword(s):  
Cell Wall ◽  
Cell Division ◽  
Secondary Wall ◽  
Secondary Growth ◽  
General Orientation ◽  
Primary Growth ◽  
Wall Growth

In primary growth, protoplasmic pressure expands the cell wall as its cellulosic framework is being built up and strengthened. Numerous micrographs provide evidence that as each lamella of the wall is differentiated, randomly spaced bonds tend to develop between its adjacent microfibrils. Apparently the number of bonds so developed, and the number retained unbroken subsequently, are related to the rate of cell wall extension.Between unbroken bonds, tensions associated with growth cause adjacent transverse microfibrils to bend successively to each side of their original general orientation. Thus, within a lamella they form lenticular, trellis-like configurations. Large extensions cause large local variations in direction; some microfibrils remain adjacent within groups, but the groups may be widely separated. Such microfibril configurations are generally incompatible with the multinet theory. Apparently also, the very large extensions of the lamellae formed soon after cell division can cause breaking of bonds, wide dispersion, and even breaking of microfibrils.In secondary growth, similar bonding between microfibrils occurs within lamellae and also between lamellae of the cell wall. Again, there is associated development of trellis configurations, but in this case it is due to swelling within the wall during lignification. Resulting changes in microfibrillar directions between bonded positions are much less extreme than in primary walls, but they are highly significant physiologically.

scholarly journals Is size an issue of time? Relationship between the duration of xylem development and cell traits

2019 ◽  
Vol 123 (7) ◽  
pp. 1257-1265 ◽  
Author(s):  
Valentina Buttò ◽  
Sergio Rossi ◽  
Annie Deslauriers ◽  
Hubert Morin
Keyword(s):  
Cell Wall ◽  
Cell Differentiation ◽  
Tree Ring ◽  
Wall Thickness ◽  
Secondary Wall ◽  
Temporal Dynamics ◽  
Secondary Growth ◽  
Growth Equation ◽  
Wall Deposition ◽  
Secondary Wall Deposition

Abstract Background and Aims Secondary growth is a process related to the formation of new cells that increase in size and wall thickness during xylogenesis. Temporal dynamics of wood formation influence cell traits, in turn affecting cell patterns across the tree ring. We verified the hypothesis that cell diameter and cell wall thickness are positively correlated with the duration of their differentiation phases. Methods Histological sections were produced by microcores to assess the periods of cell differentiation in black spruce [Picea mariana (Mill.) B.S.P.]. Samples were collected weekly between 2002 and 2016 from a total of 50 trees in five sites along a latitudinal gradient in Quebec (Canada). The intra-annual temporal dynamics of cell differentiation were estimated at a daily scale, and the relationships between cell traits and duration of differentiation were fitted using a modified von Bertalanffy growth equation. Key Results At all sites, larger cell diameters and cell wall thicknesses were observed in cells that experienced a longer period of differentiation. The relationship was a non-linear, decreasing trend that occasionally resulted in a clear asymptote. Overall, secondary wall deposition lasted longer than cell enlargement. Earlywood cells underwent an enlargement phase that lasted for 12 d on average, while secondary wall thickness lasted 15 d. Enlargement in latewood cells averaged 7 d and secondary wall deposition occurred over an average of 27 d. Conclusions Cell size across the tree ring is closely connected to the temporal dynamics of cell formation. Similar relationships were observed among the five study sites, indicating shared xylem formation dynamics across the entire latitudinal distribution of the species.The duration of cell differentiation is a key factor involved in cell growth and wall thickening of xylem, thereby determining the spatial variation of cell traits across the tree ring.

scholarly journals The Nature of Reaction Wood III. Cell Division and Cell Wall Formation in Conifer Stems

1952 ◽  
Vol 5 (4) ◽  
pp. 385 ◽  
Author(s):  
ABW Ardrop ◽  
HE Dadswell
Keyword(s):  
Cell Wall ◽  
Cell Division ◽  
Secondary Wall ◽  
Compression Wood ◽  
Normal Wood ◽  
Reaction Wood ◽  
Primary Wall ◽  
Wall Formation ◽  
Tracheid Length ◽  
Secondary Wall Formation

Cell division, the nature of extra-cambial readjustment, and the development of the secondary wall in the tracheids of conifer stems have been investigated in both compression wood and normal wood. It has been shown that the reduction in tracheid length, accompanying the development of compression wood and, in normal wood, increased radial growth after suppression, result from an increase in the number of anticlinal divisions in the cambium. From observations of bifurcated and otherwise distorted cell tips in mature tracheids, of small but distinct terminal canals connecting the lumen to the primary wall in the tips of mature tracheids, and of the presence of only primary wall at the tips of partly differentiated tracheids, and from the failure to observe remnants of the parent primary walls at the ends of differentiating tracheids, it has been concluded that extra-cambial readjustment of developing cells proceeds by tip or intrusive growth. It has been further concluded that the development of the secondary wall is progressive towards the cell tips, on the bases of direct observation of secondary wall formation in developing tracheids and of the increase found in the number of turns of the micellar helix per cell with increasing cell length. The significance of this in relation to the submicroscopic organization of the cell wall has been discussed. Results of X-ray examinations and of measurements of� tracheid length in successive narrow tangential zones from the cambium into the xylem have indicated that secondary wall formation begins before the dimensional changes of differentiation are complete.

AUTORADIOGRAPHIC STUDIES OF BACTERIAL CELL WALL REPLICATION: I. CELL WALL GROWTH OF BACILLUS CEREUS IN THE PRESENCE OF CHLORAMPHENICOL

1967 ◽  
Vol 13 (4) ◽  
pp. 341-350 ◽  
Author(s):  
K. L. Chung
Keyword(s):  
Cell Wall ◽  
Cell Division ◽  
Bacillus Cereus ◽  
First Generation ◽  
Third Generation ◽  
Cell Wall Synthesis ◽  
Daughter Cells ◽  
Entire Cell ◽  
Wall Growth ◽  
The Difference

The pattern of cell wall synthesis as measured by the incorporation of tritiated alanine into the cell wall of Bacillus cereus, and the number of synthesizing sites in the cell wall were studied by the direct and the reverse autoradiographic labelling methods.In the absence of chloramphenicol, the new cell wall was initiated at two or three segments, and later increased to four or five segments which continued to elongate but not to increase in number until the bacilli had made preparation for cell division. Shortly before the centripetal growth of the cell wall and constriction to separate daughter cells, two to three more new wall-segments were added to those already present. The second and third generation cells retained some old wall-segments from the first-generation mother, which remained as discrete clusters of grains, and could easily be distinguished from the new segments.In the presence of chloramphenicol, the new wall was initiated at 8 to 10 sites. Further incubation resulted in the uniform incorporation of labels at multiple sites along the entire cell length.The patterns of new wall replication as studied by the two methods were compared. To account for the difference in synthesizing sites when chloramphenicol is present, it is suggested that the cells have either used the maximum number of sites or have completely bypassed all the sites and allowed the tritiated alanine to diffuse into the wall to become incorporated.

The structure of the cell wall in lignifield collenchyma of Eryngium sp. (Umbelliferae)

1969 ◽  
Vol 17 (2) ◽  
pp. 229 ◽  
Author(s):  
AB Wardrop
Keyword(s):  
Cell Wall ◽  
Cell Division ◽  
Cell Differentiation ◽  
Secondary Wall ◽  
Indoleacetic Acid ◽  
Cellulose Microfibrils ◽  
Cell Axis ◽  
Wall Formation ◽  
Microfibril Orientation ◽  
Secondary Wall Formation

In Eryngium vesiculosum and E. rostratum, the leaf collenchyma is characterized by the development of a lignified secondary wall in the final stages of cell differentiation. The collenchyma wall is rich in pectic substances which are distributed uniformly. In the outer limiting region of the collenchyma wall the microfibril orientation is random and this structure is considered to be the wall formed at cell division. The collenchyma wall consists of six to eight layers in which the microfibrils are alternately transversely and longitudinally oriented. Each layer consists of a number of lamellae of microfibrils. In the secondary lignified wall the cellulose microfibrils are arranged helically, the direction of their orientation making an angle of 40-45° to the cell axis. Excised leaf segments showed greatest elongation in solutions of glucose and 3-indoleacetic acid, when the collenchyma walls were thin, and no elongation occurred in segments in which secondary wall formation had commenced. In radial sections layers of transversely oriented microfibrils could not be seen distant from the lumen although discontinuities in wall texture were apparent. Layers of transversely oriented microfibrils could be seen adjacent to the lumen. It is suggested that reorientation of layers of initially transversely oriented microfibrils takes place during elongation of the cells.

CELL WALL REPLICATION: II. CELL WALL GROWTH AND CROSS WALL FORMATION OF ESCHERICHIA COLI AND STREPTOCOCCUS FAECALIS

1964 ◽  
Vol 10 (3) ◽  
pp. 473-482 ◽  
Author(s):  
K. L. Chung ◽  
R. Z. Hawirko ◽  
P. K. Isaac
Keyword(s):  
Cell Wall ◽  
Cell Division ◽  
Initial Step ◽  
Wall Material ◽  
Cross Wall ◽  
Cell Wall Growth ◽  
E Coli ◽  
Rapid Enlargement ◽  
Wall Growth ◽  
Polar Type

Cell wall replication in E. coli and S. faecalis was studied by differential labelling of living cells with fluorescent and non-fluorescent antibody.In E. coli the initial step in cell division was the formation of a cross wall at the cell equator, followed by the appearance of new cell wall on either side of the cross wall. The process was repeated in sequence at subsequent sites in the polar, the subcentral, and the subpolar areas. Constriction occurred at random so that the divided parent cells were composed of several daughter cells.A polar type of unidirectional cell wall growth and elongation was also observed in E. coli. It was initiated by the synthesis of a ring of new cell wall material around the polar tip. A second ring was then formed at the subpolar area during the rapid enlargement of the first ring in a single direction.Evidence shows that cell wall synthesis is independent of cell division and that in E. coli, it is initiated at multiple but specific sites within the cell and not by diffuse intercalation of old and new walls.Contrary to the synthesis of cell wall at multiple sites in E. coli, S. faecalis replicated new cell wall at only one site per coccus. The new wall segment was initiated and enlarged at the coccal equator, and was followed by the formation of a cross wall, centripetal growth and constriction to separate the daughter cells.

scholarly journals MYB Transcription Factors and Its Regulation in Secondary Cell Wall Formation and Lignin Biosynthesis during Xylem Development

2021 ◽  
Vol 22 (7) ◽  
pp. 3560
Author(s):  
Ruixue Xiao ◽  
Chong Zhang ◽  
Xiaorui Guo ◽  
Hui Li ◽  
Hai Lu
Keyword(s):  
Cell Wall ◽  
Transcription Factors ◽  
Secondary Wall ◽  
Secondary Cell Wall ◽  
Lignin Biosynthesis ◽  
Cell Wall Formation ◽  
Long Distance ◽  
Secondary Cell Wall Formation ◽  
Myb Transcription Factors ◽  
Wall Formation

The secondary wall is the main part of wood and is composed of cellulose, xylan, lignin, and small amounts of structural proteins and enzymes. Lignin molecules can interact directly or indirectly with cellulose, xylan and other polysaccharide molecules in the cell wall, increasing the mechanical strength and hydrophobicity of plant cells and tissues and facilitating the long-distance transportation of water in plants. MYBs (v-myb avian myeloblastosis viral oncogene homolog) belong to one of the largest superfamilies of transcription factors, the members of which regulate secondary cell-wall formation by promoting/inhibiting the biosynthesis of lignin, cellulose, and xylan. Among them, MYB46 and MYB83, which comprise the second layer of the main switch of secondary cell-wall biosynthesis, coordinate upstream and downstream secondary wall synthesis-related transcription factors. In addition, MYB transcription factors other than MYB46/83, as well as noncoding RNAs, hormones, and other factors, interact with one another to regulate the biosynthesis of the secondary wall. Here, we discuss the biosynthesis of secondary wall, classification and functions of MYB transcription factors and their regulation of lignin polymerization and secondary cell-wall formation during wood formation.

scholarly journals Probing bacterial cell wall growth by tracing wall-anchored protein complexes

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yi-Jen Sun ◽  
Fan Bai ◽  
An-Chi Luo ◽  
Xiang-Yu Zhuang ◽  
Tsai-Shun Lin ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Shape ◽  
Bernoulli Shift ◽  
Protein Complexes ◽  
Axial Direction ◽  
Cell Wall Growth ◽  
Flagellar Motors ◽  
Shift Map ◽  
Dynamic Assembly ◽  
Wall Growth

AbstractThe dynamic assembly of the cell wall is key to the maintenance of cell shape during bacterial growth. Here, we present a method for the analysis of Escherichia coli cell wall growth at high spatial and temporal resolution, which is achieved by tracing the movement of fluorescently labeled cell wall-anchored flagellar motors. Using this method, we clearly identify the active and inert zones of cell wall growth during bacterial elongation. Within the active zone, the insertion of newly synthesized peptidoglycan occurs homogeneously in the axial direction without twisting of the cell body. Based on the measured parameters, we formulate a Bernoulli shift map model to predict the partitioning of cell wall-anchored proteins following cell division.

Cell grouping and primary wall generations in the cambial zone, xylem, and phloem in Pinus

1968 ◽  
Vol 16 (2) ◽  
pp. 177 ◽  
Author(s):  
A Mahmood
Keyword(s):  
Cell Division ◽  
Mother Cell ◽  
Secondary Wall ◽  
Radial Direction ◽  
Cell Plate ◽  
Tangential Direction ◽  
Primary Wall ◽  
Photographic Evidence ◽  
Secondary Wall Deposition ◽  
Cambial Zone

The use of the term cambium, or equivalent terms, in modern literature is discussed. The term cambial zone adopted in this paper includes the cambial initial and the dividing and enlarging cells. The tissue mother cell produced at each division of the initial produces a group of four cells in xylem or two cells in phloem. Theoretical constructs have been made for xylem and phloem production by associating the concepts that xylem and phloem are produced in alternate series of initial divisions and that a new primary wall is deposited around each daughter protoplast at each cell division. Correlations are derived from the theoretical constructs for the thickness of primary wall layers lying in the tangential direction and of those lying in the radial direction at progressive histological levels. Deductions from theoretical constructs are made when the initial is producing xylem, when it changes its polarity from xylem to phloem production, and when the reverse change occurs. Most of the theoretical deductions are supported by photographic evidence. The chief point of this study is the demonstration of generations (multiplicity) of primary parental walls. The term intercellular material proposed in this paper includes the cell plate plus any remnants of ancestral primary walls between the current primary walls surrounding the adjacent protoplasts. This term is still applicable to cells where secondary wall deposition is taking place or has been completed.

The nature of reaction wood. IV. Variations in cell wall organization of tension wood fibres

1955 ◽  
Vol 3 (2) ◽  
pp. 177 ◽  
Author(s):  
AB Wardrop ◽  
HE Dadswell
Keyword(s):  
Cell Wall ◽  
Tension Wood ◽  
Secondary Wall ◽  
Degree Of Crystallinity ◽  
Tropical Species ◽  
Normal Wood ◽  
Reaction Wood ◽  
Gelatinous Layer ◽  
Wood Fibres ◽  
Cell Wall Organization

The cell wall organization, the cell wall texture, and the degree of lignification of tension wood fibres have been investigated in a wide variety of temperate and tropical species. Following earlier work describing the cell wall structure of tension wood fibres, two additional types of cell wall organization have been observed. In one of these, the inner thick "gelatinous" layer which is typical of tension wood fibres exists in addition to the normal three-layered structure of the secondary wall; in the other only the outer layer of the secondary wall and the thick gelatinous layer are present. In all the tension wood examined the micellar orientation in the inner gelatinous layer has been shown to be nearly axial and the cellulose of this layer found to be in a highly crystalline state. A general argument is presented as to the meaning of differences in the degree, of crystallinity of cellulose. The high degree of crystallinity of cellulose in tension wood as compared with normal wood is attributed to a greater degree of lateral order in the crystalline regions of tension wood, whereas the paracrystalline phase is similar in both cases. The degree of lignification in tension wood fibres has been shown to be extremely variable. However, where the degree of tension wood development is marked as revealed by the thickness of the gelatinous layer the lack of lignification is also most marked. Severity of tension wood formation and lack of lignification have also been correlated with the incidence of irreversible collapse in tension wood. Such collapse can occur even when no whole fibres are present, e.g. in thin cross sections. Microscopic examination of collapsed samples of tension wood has led to the conclusion that the appearance of collapse in specimens containing tendon wood can often be attributed in part to excessive shrinkage associated with the development of fissures between cells, although true collapse does also occur. Possible explanations of the irreversible shrinkage and collapse of tension wood fibres are advanced.

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