CELL LENGTH AND RATE OF ANTICLINAL DIVISION IN THE CAMBIUM OF THE SEQUOIAS

1966 ◽  
Vol 44 (2) ◽  
pp. 209-218 ◽  
Author(s):  
M. W. Bannan

This report deals with the frequency of anticlinal (multiplicative) divisions in fusiform cambial cells, cell length at the time of division, and ring width as determined mostly in Sequoia sempervirens. The general relationships between these anatomical features resembled those observed in other conifers, but the frequency of anticlinal division was relatively high and the cells were long. Accordingly, the rate of cambial cell lengthening in the repetitive cycle of anticlinal division and cell elongation was found to exceed that in other conifers. Upward in the lower part of the stem the rate of anticlinal division decreased and cell length increased. A comparatively high rate of anticlinal division was maintained in the peripheral growth of large boles in both species, but cell length was greater in S. sempervirens than in S. gigantea.


1967 ◽  
Vol 45 (8) ◽  
pp. 1359-1369 ◽  
Author(s):  
M. W. Bannan

The early growth of a tree is marked by a widening of the annual increments, a deceleration in rate of multiplicative (anticlinal) division of fusiform cambial cells, and an increase in cell length. Distance outward from the pith at which maximation in cell size occurs, and subsequent trends in cell dimensions, are apparently modified by rate of growth. Continuation of a uniform ring width through the middle to late years favors comparative constancy in rate of anticlinal division and cell size during that stage of tree development. Reduction in amount of annual increment in the late growth to the width optimal for cell extension, about 1 mm, induces a delayed and probably heightened maximation in cell length. Continued lessening in radial growth to an annual accretion of 0.5 mm or less, with the onset of senility, results in acceleration in rate of multiplicative division and reduction in cell length.



1965 ◽  
Vol 43 (4) ◽  
pp. 429-435 ◽  
Author(s):  
M. W. Bannan

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.



1963 ◽  
Vol 41 (8) ◽  
pp. 1187-1197 ◽  
Author(s):  
M. W. Bannan

Differences of considerable magnitude occur in the tracheid dimensions of North American species of Cupressus. In general the species in arid regions (C. arizonica, C. glabra, C. forbesii, and C. macnabiana) have smaller cells than the species in more humid localities (C. macrocarpa and C. pygmaea). Minor, in some cases questionably significant, differences in cell size are found at different sites for the same species. Noteworthy interspecific differences exist in the frequency of anticlinal (pseudotransverse) divisions involved in cambial cell multiplication. On the whole, these divisions take place at a faster rate in the species with small cells (C. arizonica, C. macnabiana) than in species with large cells (C. pygmaea). Some general relationships between rate of growth, frequency of pseudotransverse divisions, and cell length are also evident. In the stems of mature trees, maximum cell length is apparently associated with a ring width of approximately 1–1.5 mm. Reduction in ring width is accompanied by a rise in frequency of pseudotransverse division and a slight recession in cell length. Widening of the rings produces no change in the rate of anticlinal division, in relation to linear radial accretion, but cell length declines. The orientation of the partition in pseudotransverse division is usually unidirectional in neighboring cells, but reversals in tilt occur after varied intervals. Duration of the interval between reversals shows an inverse relationship with the frequency of pseudotransverse division.



1962 ◽  
Vol 40 (8) ◽  
pp. 1057-1062 ◽  
Author(s):  
M. W. Bannan

The relationships between width of annual rings, length of wood cells, and frequency of anticlinal (multiplicative) divisions in fusiform cambial cells were studied by reference to trees of various growth patterns. The trees selected ranged from 8 to 20 in. diameter and included both open-grown specimens with branches close to the ground and forest types with tall, slender shafts. Much fluctuation was noted among individual trees, but in general there was, in the peripheral growth, an inverse relationship between length of wood cells and width of annual rings. The frequency of anticlinal divisions in the cambium remained at a more or less uniform rate in trees with rings from 1.5 to 5 mm wide, but rose sharply when ring width fell below 1.3 mm. This was in contrast to the situation observed earlier in Thuja occidentalis where the rise in frequency of anticlinal divisions was slight and occurred only in trees with rings less than 0.3 mm wide.



1970 ◽  
Vol 48 (7) ◽  
pp. 1363-1371 ◽  
Author(s):  
M. W. Bannan ◽  
M. Bindra

In the early growth of the stem, branches, and roots, the vascular elements are relatively short and the frequency of anticlinal division involved in cambial cell multiplication is high. As growth sheaths are added in the stem, length of cell increases and rate of multiplicative division declines. A similar trend occurs upward through the lower quarter to half the height of the stem. In the root system, the later growth of vertical roots is characterized by shortness of cell and high frequency of anticlinal division, and conversely, that of horizontal roots by great length of cell and low rate of anticlinal division. Although a general negative relationship exists between rate of anticlinal division and cell length throughout much of the tree, these features sometimes vary independently, and length of cell seems to be more closely related to amount of yearly radial accretion. Through the middle to late growth of the stem a negative relationship obtains between length of cell and width of annual ring, cell length maximating at a ring width of 1–2 mm. At this stage, frequency of division may fluctuate only narrowly over a considerable range of ring width. A continued decline in ring width to less than 0.5 mm, such as may occur on senescence, is accompanied by decreased cell length and accelerated anticlinal division. Length of the cell plate in anticlinal division, relative to that of the dividing cell, is greater in the early growth of the stem and branches and throughout horizontal roots than elsewhere in the tree. Most of the anticlinal divisions are pseudotransverse. The proportion of lateral divisions ranges from about 1% in the late growth of stems to 11% in horizontal roots.



1965 ◽  
Vol 43 (5) ◽  
pp. 487-508 ◽  
Author(s):  
M. W. Bannan

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.



1964 ◽  
Vol 42 (9) ◽  
pp. 1105-1118 ◽  
Author(s):  
M. W. Bannan

Tracheid size and rate of anticlinal divisions in the cambium were determined for lodgepole pine at several sites in western North America ranging in elevation from 3000 to 11,000 feet. The determinations were made at breast height in trees with boles 10–20 in. in diameter. The base rate of anticlinal division was low as compared with other conifers, the average being 0.8 divisions per cm of xylem increment when ring width exceeded 1.5 mm. The frequency of division increased as annual xylem production fell below 1 mm, and rose sharply with continued reduction in ring width under 0.3 mm. Maximum cell length was associated with a ring width of 1 mm, and the length decreased in both wide and narrow rings. The tangential width of the tracheids likewise lessened as ring width fell below 1 mm, the decline becoming accentuated with continued waning of growth to less than 0.3 mm. Cell diameter differed from the overall mean by more than 1 µ at only one site after allowance was made for dissimilarities in growth rate. Cells were shortest at the two highest sites. The newly formed partition in pseudotransverse division tended to be inclined in the same direction in neighboring cells, but the percentage of divisions deviating from the preferred orientation was higher than in other conifers. Reversals in direction of tilt occurred after varied intervals, these apparently being corrective in function.



1960 ◽  
Vol 38 (5) ◽  
pp. 795-802 ◽  
Author(s):  
M. W. Bannan

Through the growth of the first few years, when the perimeter of the stem is fast expanding, the multiplicative pseudotransverse divisions in fusiform cambial cells occur in relatively rapid sequence, the ratio of survival of newly formed cambial cells is high, and continuous increase in mean cell length ensues. Accommodation of the cambium to circumferential expansion is thus facilitated. With increasing age and diminishing rate of perimeter growth the frequency of pseudotransverse division declines, the survival rate of new-formed cambial initials drops, and increase in cell length slackens. This gradual flattening off may continue through to the final growth, but more often fluctuations in rate of anticlinal division and cell length arise in the middle to late growth, these not always exhibiting close interrelationship. Sometimes high rates of pseudotransverse division occur in the late growth which are accompanied by only moderate reductions in cell length.



1960 ◽  
Vol 38 (2) ◽  
pp. 177-183 ◽  
Author(s):  
M. W. Bannan

The relationship between ring width and length of wood cells was studied by reference to mature white cedar trees of various growth patterns. These included trees of similar diameter but diverse growth rates, trees with transition from wide to narrow rings or from narrow to wide rings in their peripheral growth, and trees with rings varying in width in different radii. Although much fluctuation occurred among individuals there was in general an inverse relationship between cell length and ring width. On the other hand, the variations in frequency of pseudotransverse divisions in the cambium, which might be expected to have a profound influence on cell length because of their involvement in cambial cell multiplication, were not obviously related to the growth rate. The frequency of pseudotransverse divisions in the fusiform initials apparently is geared neither to circumferential expansion nor to number of periclinal divisions in the cambium but rather seems to be related simply to linear radial increment.



1963 ◽  
Vol 41 (6) ◽  
pp. 811-822 ◽  
Author(s):  
M. W. Bannan

This study deals with the relationships between length of wood cells, width of annual rings, and frequency of multiplicative (pseudotransverse) divisions in fusiform cambial cells of Picea. Species investigated were P. engelmanni, P. glauca, P. mariana, and P. sitchensis. Observations were based on the recent growth of trees 10–20 in. in diameter, and in the case of P. sitchensis included trees up to 7 ft in diameter. In general, maximum cell length was associated with a ring width of 1–2 mm. Cell length declined with increase in ring width, and also decreased slightly when ring width fell below the optimum level. The frequency of pseudotransverse divisions in the cambium remained at a more or less uniform rate in trees with rings 2–8 mm wide, but rose sharply as ring width dropped below 1 mm. The slight reduction in cell length in narrow rings was apparently associated with the rise in frequency of multiplicative divisions in the cambium. Maximum cell length was observed in P. sitchensis. The shortest cells and lowest frequency of multiplicative divisions were noted in P. engelmanni. As ring width decreased a higher proportion of the pseudotransverse divisions occurred during the late seasonal growth. The orientation of the partition in pseudotransverse division tended to be unidirectional, but reversals in direction of tilt occurred after varied intervals.



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