scholarly journals Interrelationship between mean length, rate of intrusive elongation, frequency of anticlinal divisions and survival of fusiform initials in cambium

2015 ◽  
Vol 36 (2) ◽  
pp. 367-378 ◽  
Author(s):  
Z. Hejnowicz
Keyword(s):  
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.

Cambial activity and ray cell abundance in Acer saccharum

1977 ◽  
Vol 55 (20) ◽  
pp. 2559-2564 ◽  
Author(s):  
R. A. Gregory
Keyword(s):  
Growth Rate ◽  
Acer Saccharum ◽  
Unit Area ◽  
Ring Width ◽  
Cambial Activity ◽  
Relative Volume ◽  
Annual Ring Width ◽  
Ray Cells ◽  
Fusiform Initials ◽  
Ray Cell

The ratio of ray and ray cell initials to fusiform initials of the vascular cambium relative to radial growth rate as reflected in the secondary xylem was studied in stems of Acer saccharum Marsh. Ray initials increased in size as they aged, slowly when growth rate was low, rapidly when it was high, but there was little fluctuation in the number of rays per unit of tangential area; as the cambium increased in circumference, the older, larger rays diverged and new small rays arose in intervening areas, thus maintaining a uniform unit area population independent of growth rate. However, since ray size increased rapidly when growth rate was high, the unit area population of ray cells rose abruptly with accelerating growth rate: the relative volume of xylem ray tissue rose from 8.6 to 12.7% of the total xylem volume when annual ring width increased from 1 to 7 mm. When fast growth was not maintained, the unit area population of ray cells declined slowly as the large rays diverged.

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.

The Ratio of Ray and Fusiform Initials in some Plants Dominating Mediterranean Formations in Greece

Flora ◽  
1977 ◽  
Vol 166 (3) ◽  
pp. 219-222 ◽  
Author(s):  
N.S. Margaris ◽  
P. Papadogianni
Keyword(s):  
Fusiform Initials

scholarly journals Microgenomic analysis reveals cell type-specific gene expression patterns between ray and fusiform initials within the cambial meristem ofPopulus

2008 ◽  
Vol 180 (1) ◽  
pp. 45-56 ◽  
Author(s):  
Nadia Goué ◽  
Marie-Claude Lesage-Descauses ◽  
Ewa J. Mellerowicz ◽  
Elisabeth Magel ◽  
Philippe Label ◽  
...  
Keyword(s):  
Gene Expression ◽  
Expression Patterns ◽  
Gene Expression Patterns ◽  
Specific Gene ◽  
Cell Type ◽  
Specific Gene Expression ◽  
Fusiform Initials ◽  
Cell Type Specific

Parallelism and Reversibility in Xylem Evolution a Review

IAWA Journal ◽  
1996 ◽  
Vol 17 (4) ◽  
pp. 351-364 ◽  
Author(s):  
Pieter Baas ◽  
Elisabeth A. Wheeler
Keyword(s):  
Phylogenetic Analyses ◽  
Distribution Patterns ◽  
Seed Plants ◽  
Hydraulic Architecture ◽  
Primitive Angiosperms ◽  
Perforation Plate ◽  
High Incidence ◽  
Fusiform Initials ◽  
Plate Type ◽  
Transformation Series

The irreversibility of the major trends of xylem evolution, such as the origin of vessels in primitive angiosperms with long fusiform initials, and the shifts from scalariform to simple perforations and from tracheids to libriform fibres, has long been accepted by wood anatomists. Parallel development of these and other xylem features is generally accepted, and is suggested by the distribution patterns of the fibre and perforation plate type. Some recent phylogenetic analyses of seed plants suggest that there also have been some reversals in these general trends. The likelihood and extent of parallel origins and reversions of the major trends in xylem specialization are explored here by analysing a number of published hypotheses on the phylogenetic relationships within wood anatomically diverse major clades of angiosperms, and within some individual families. On the basis of these analyses, it appears that for these major Baileyan transformation series, parallelisms were more than twice as common as reversals. Functional adaptations to increased efficiency and safety of hydraulic architecture can largely explain the high incidence of parallelisms in xylem evolution.

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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