THE REDUCTION OF FUSIFORM CAMBIAL CELLS IN CHAMAECYPARIS AND THUJA

1951 ◽  
Vol 29 (1) ◽  
pp. 57-67 ◽  
Author(s):  
M. W. Bannan
Keyword(s):  
Frequent Occurrence ◽  
Daughter Cells ◽  
Fusiform Initials ◽  
Cambial Cells ◽  
Fusiform Initial ◽  
Ray Initials

The loss of fusiform initials from the cambium, which is of frequent occurrence in all parts of the tree, takes place in different ways. Some cambial cells seem gradually to fail and are shortly lost from the cambium by maturation into more or less imperfect xylem or phloem elements. The majority are transversely subdivided by one or a succession of anticlinal divisions which begin near the center of the fusiform initial and usually extend to the daughter cells. The resulting segments shorten through the following periclinal divisions, some disappearing during the process of shortening and others undergoing transformation to ray initials. Nearly all new rays in the secondary body originate in this manner.

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.

THE ANNUAL CYCLE OF SIZE CHANGES IN THE FUSIFORM CAMBIAL CELLS OF CHAMAECYPARIS AND THUJA

1951 ◽  
Vol 29 (4) ◽  
pp. 421-437 ◽  
Author(s):  
M. W. Bannan
Keyword(s):  
Annual Cycle ◽  
Annual Ring ◽  
Growing Season ◽  
Fusiform Initials ◽  
Cambial Cells ◽  
Ray Initials

In stems exceeding a few inches in diameter most of the pseudotransverse divisions involved in the multiplication of fusiform cambial cells occur toward the end of the growing season. Often these aestival transverse divisions are immediately followed by extensive elongation of the new-formed cambial Cells, especially at their overlapping tips. In the succeeding year relatively slight elongation ensues during the development of the first quarter of the annual ring, but through the succeeding quarters the amount of extension increases and is usually maximal in the final quarter. The actual rates of elongation remain undetermined. The multiplication of fusiform initials is accompanied by loss, most of the failure taking place during the last quarter. Generally the fusiform initials with the most extensive ray contacts survive and enlarge, and those with poor ray associations fail or are reduced to potential ray initials. The elongation and multiplication of fusiform initials tend to produce local ray deficiencies. Reduction of the fusiform initials with the poorest ray contacts to ray initials rectifies to varying extent the ray shortages in those areas.

FURTHER OBSERVATIONS ON THE REDUCTION OF FUSIFORM CAMBIAL CELLS IN THUJA OCCIDENTALIS L.

1953 ◽  
Vol 31 (1) ◽  
pp. 63-74 ◽  
Author(s):  
M. W. Bannan
Keyword(s):  
Cell Division ◽  
Cell Volume ◽  
Cell Shape ◽  
Transitional Period ◽  
Radial Expansion ◽  
Cambial Cell ◽  
Thuja Occidentalis ◽  
Daughter Cells ◽  
Fusiform Initials ◽  
Cambial Cells

The multiplication of fusiform initials in the cambium is accompanied by extensive loss or transformation of these cells. A few of the failing cambial cells lapse into maturation quickly, but the majority are transversely subdivided with varying proportions of the segments surviving and undergoing ultimate conversion to ray initials. The loss or conversion is attended with reduction in cell size. Increase in cell volume lags behind cell division during the periclinal divisions of the transitional period. The tangential dimensions of the successively formed cells are continuously reduced, and sometimes radial expansion is also retarded, especially toward the cell tips. Simultaneous shortening of the cells is due to alteration in cell shape combined with asymmetry in periclinal division such that daughter cells of unequal lengths are produced. Repetition of the process, the smaller cell functioning as the initiating cambial cell in each instance, results in continued shortening.

THE RELATIVE FREQUENCY OF THE DIFFERENT TYPES OF ANTICLINAL DIVISIONS IN CONIFER CAMBIUM

1957 ◽  
Vol 35 (6) ◽  
pp. 875-884 ◽  
Author(s):  
M. W. Bannan
Keyword(s):  
Relative Frequency ◽  
Small Cells ◽  
Rate Of Growth ◽  
Different Types ◽  
Anticlinal Division ◽  
Fusiform Initials ◽  
Cambial Cells ◽  
Mother Cells ◽  
Ray Initials

The fusiform cambial cells of conifers undergo two types of anticlinal division, pseudotransverse division and division to produce small cells off the side. Pseudotransverse divisions are largely confined to the cambial initials, only a small percentage of such divisions occurring in the derived tissue mother cells. The incidence of pseudotransverse divisions outside the layer of initials tends to rise with the rate of growth. Divisions of the second type, to yield segments off the side, are infrequent and seem generally to involve only the fusiform initials. Behavior of the abscissed segments bears some relationship to size, the shortest segments usually failing, those of intermediate length tending to become reduced to one or more ray initials, and the largest developing as fusiform initials.

SPIRAL GRAIN AND ANTICLINAL DIVISIONS IN THE CAMBIUM OF CONIFERS

1966 ◽  
Vol 44 (11) ◽  
pp. 1515-1538 ◽  
Author(s):  
M. W. Bannan
Keyword(s):  
High Ratio ◽  
Contributory Factor ◽  
Relative Duration ◽  
Mature Trees ◽  
Spiral Grain ◽  
Anticlinal Division ◽  
Fusiform Initials ◽  
The Mean ◽  
Cambial Cells ◽  
The Right

In the cambium of mature trees a general conformity was found in the orientation of the partition in the pseudotransverse division of fusiform initials through out sectors of varying size. The proportion of divisions deviating from the preferred orientation varied with the tree, the locality, and the species, but was usually less than 10%. As radial accretion followed, periodic reversals occurred in the orientation of anticlinal divisions, the spacing between reversals, in terms of xylem increment, being related to the frequency of anticlinal division. The mean interval shortened as the rate of division rose according to the equation xy = k. While this overall relationship obtained, there was generally some inequality in the relative duration of leftward and rightward orientations of division. In species with grain in the outer wood slanted to the right, a rightward tilt of division persisted for longer periods than a leftward tilt. Conversely, in species with grain slanted to the left, thickness of xylem showing leftward orientation of multiplicative divisions exceeded that with rightward orientation. Changes associated with growth from sapling to adult were studied in Picea, in which genus grain is usually to the left in the inner wood and to the right in the outer wood. Here multiplicative divisions were usually inclined to the left in the growth of the first few years, whereas in the later growth orientation to the right endured for longer periods than to the left. Both orientation of pseudo-transverse division and direction of cell elongation after division seem to be under a general polar control. This apparently is an important element in the induction of spiral grain. Above-average net gain of fusiform initials in the turmoil of cell addition and loss, which accompanies circumferential expansion, may be a contributory factor. Serving to restrain the development of an excessive spirality are periodic reversals in direction of tilt in anticlinal division, and a high ratio of loss of cambial cells relative to the frequency of anticlinal division.

scholarly journals Size variation in the vascular cambium and its derivatives in two Alstonia species

2007 ◽  
Vol 21 (3) ◽  
pp. 531-538 ◽  
Author(s):  
Moin A. Khan ◽  
Badruzzaman Siddiqui
Keyword(s):  
Size Variation ◽  
Tropical Tree Species ◽  
Edaphic Conditions ◽  
Appreciable Increase ◽  
Ray Cells ◽  
Fusiform Initials ◽  
Xylem Ray Cells ◽  
Mother Cells ◽  
Xylem Fibers ◽  
Fusiform Initial

Two tropical tree species viz. Alstonia venenata Br. and Alstonia neriifolia Don. (Apocynaceae) were investigated to detect size variation in different elements of the cambium and its derivative tissues. Although these two species were grown under identical climatic and edaphic conditions, fusiform initial dimensions and the elements derived from them were larger in A. venenata than in A. neriifolia. Ray initials are rectangular in A. venenata but isodiametric in A. neriifolia. An appreciable increase in length was observed in the phloem and xylem ray cells when compared to the mother cells. Maximum elongation was observed in xylem fibers during differentiation from the respective fusiform initials.

scholarly journals Desenvolvimento e mudanças celulares na estrutura dos raios xilemáticos de Rollinia emarginata Schlecht. (Annonaceae)

1988 ◽  
Vol 10 (10) ◽  
pp. 131
Author(s):  
Paulo Cesar Botosso
Keyword(s):  
Secondary Xylem ◽  
Intrusive Growth ◽  
Outermost Layer ◽  
Cellular Changes ◽  
Fusiform Initials ◽  
Cellular Transformations ◽  
Ray Initials

Through microscopical observations in serial tangential sctions from cambium to pith the development and the most significant cellular changes in the structure of rays of Rollinia emarginata Schlecht. (Annonaceae) were observed. The ray characteristics of the outermost layer of secondary xylem are described and the major changes in the ray structure in different stages of secondary develooment are considered. The cellular changes observed are extremely variable, occurring isolated or in complex combinations. The most significant cellular changes observed during ray development are the following: origin of ray initials from fusiform initials or from cambial ray initials; changes resulting from the intrusive growth of fusiform initials through a group of ray initials and the loss of ray initials from the cambium. From these cellular transformations the most important changes in the origin of secondary rays, increase in height and width and reduction in the height of multisseriate rays are considered.

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.

RAY CONTACTS AND RATE OF ANTICLINAL DIVISION IN FUSIFORM CAMBIAL CELLS OF SOME PINACEAE

1965 ◽  
Vol 43 (5) ◽  
pp. 487-508 ◽  
Author(s):  
M. W. Bannan
Keyword(s):  
Cell Multiplication ◽  
Cambial Cell ◽  
Intrinsic Factors ◽  
Ray Parenchyma ◽  
Ray Cells ◽  
Anticlinal Division ◽  
Fusiform Initials ◽  
Ray Parenchyma Cells ◽  
Cambial Cells ◽  
Resin Canals

The frequency of pseudotransverse divisions involved in cambial cell multiplication was found to be slightly higher in fusiform initials bordering on fusiform rays than in other cambial cells. The extent of difference was greater in Pinus than in Pseudotsuga or Picea. Because of the larger size of fusiform rays as compared to uniseriate rays, cambial cells adjoining the former were in contact with more ray cells per millimeter of cell length than cambial cells touching only uniseriate rays. As with the frequency of pseudotransverse division, the margin of difference in extent of ray contact was greater in Pinus than in Pseudotsuga or Picea. The evidence therefore indicates that the higher rate of pseudotransverse division in cambial cells adjoining fusiform rays was correlated with the greater area of ray contact, or more specifically, the increased contact with ray parenchyma cells. The higher rate of anticlinal division was apparently the consequence of an increase in ratio of survival of daughter initials arising in pseudotransverse division, some of the smaller newly formed initials persisting in contrast to the usual failure of similar initials situated elsewhere in the cambium. Mean height of uniseriate rays tended to increase with widening of the annual rings, but the size of fusiform rays was influenced to a much smaller degree. The frequency of fusiform rays, and horizontal resin canals, showed no consistent relationship with growth rate, but appeared to be determined by intrinsic factors.

Vertical migration of rays leads to the development of a double-storied phenotype in the cambium of Aesculus turbinata

Botany ◽  
2008 ◽  
Vol 86 (1) ◽  
pp. 36-44 ◽  
Author(s):  
Elżbieta Myśkow ◽  
Beata Zagórska-Marek
Keyword(s):  
Vertical Migration ◽  
Hippophae Rhamnoides ◽  
Vascular Cambium ◽  
Common Descent ◽  
Hippophaë Rhamnoides ◽  
Fusiform Initials ◽  
Hippophae Rhamnoïdes L ◽  
Ray Cell ◽  
Ray Initials

In the vascular cambium of Aesculus turbinata (Blume) the double-storied structure develops slowly. Initially, the arrangement of primary rays is nonstoried. New secondary rays are initiated during cambial expansion. Rays grow by addition of new initials at both ray margins and then split by the intrusive elongation of adjacent fusiform cells. The repetitive splits give rise to groups of several rays of common descent. Initially, the secondary rays are also nonstoried. Later, they become organized into horizontal tiers. This results from the vertical migration of ray initials in the vascular cambium. Controlled polar additions and eliminations of ray-cell initials at the opposite margins of the ray continue until it reaches the appropriate position within the storey of fusiform initials. We postulate that there are at least two mechanisms for the formation and maintenance of ray tiers in cambium. They are unrelated to cell inclination changes, which as described earlier, are known to sometimes induce a double-storied phenotype. The first of these mechanisms, involves initiation of secondary rays exactly within the storeys of fusiform initials, as in Hippophaë rhamnoides L. The second mechanism, present in A. turbinata, is based on the dynamic, controlled migration of rays.

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