THE ELONGATION OF FUSIFORM CAMBIAL CELLS IN CHAMAECYPARIS

Abstract

Studies of the secondary xylem and phloem indicated that after their origin in anticlinal division, sister fusiform initials usually elongated rapidly, particularly at their overlapping tips. After this first phase, rate and amount of extension varied, both along the overlap and at the opposite ends. Often elongation proceeded in a somewhat periodic fashion, being determined in part by inherent factors and in part by position and behavior of the adjoining cells. Sometimes elongating tips were temporarily stalled at blocking rays, while at other times very rapid extension occurred in association with loss of a neighboring initial from the cambium. Growth appeared to be apical, "intrusive" in the sense that the elongating tips thrust between other cells. No evidence was found to support the theory of simultaneous elongation of considerable portions of adjoining walls by "symplastic" growth.

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

“…The rapid sequence of anticlinal divisions and the subsequent elimination of many of the daughter cells of these divisions, illustrated in Figures 1 and 2, effect a considerable change in the pattern made by the cambial initials on the tangential face of the developing stem. The results of the present investigation add confirmation to those given in a series of papers by Bannan and Whalley (Bannan and Whalley 1950;Whalley 1950;Bannan 1950Bannan , 1951, who have concluded that readjustment of the daughter cells following anticlinal divisions involves tip growth of the cells rather than the relatively slow symplastic readjustment proposed by Priestley (1930) and subsequently supported by Meeuse (1941). ....…”

“…However, the recent work of Bannan and Whalley (1950) has demonstrated that the frequency of these divisions is very much greater than w:,ls previously supposed. From the changing pattern of the differentiating tracheids seen in longitudinal tangential sections, these investigators have concluded that increase in length of the daughter cells, following anticlinal divisions, results from tip growth.…”

“…Each section, as cut, was numbered according to the growth ring and its position in the ring, or, where no growth rings were evident, according to its position in the specimen. All sections were examined microscopically to determine the sequence of anticlinal divisions according to the procedure adopted by Bannan and Whalley (1950), This method, used originally by Klinken (1914), involves a number of assumptions, among the most important of which are: (i) The arrangement and length of the tracheids approximately recapitulate the arrangement and length of the fusiform initials of the cambium 'at the time the tracheids were cut off; (ii) The appearance of two tracheids as seen in serial tangential sections, instead of one, has involved the occurrence of an anticlinal division; and (iii) The disappearance of a tracheid from a radial file has involved the disappearance of a fmiform initial from the cambium.…”

Growth and Morphogenesis in the Canadian Forest Species: Ii. Specific Increments and Their Relation to the Quantity and Activity of Growth in Pinus Resinosa Ait.

“…1,Tntil the wctrk o f Han11al2 a/. (1)(2)(3)(4)(5)(6)(7)(8)(9)24) rt:vealeci tlic a-ernark;li;~le procct.dings i~~volvecl iln tBii:, part of t-klc~ growth process anid c8crnonstrated 1 1 0 1~ far from si~nple is the 1)iological colitrol o l t%sis function, it 81,lcl been sul)l~oscd that tlae 11uml)er of annual alltic:lin,~l divisions 111ipht be, rt'lc'~tiv~1y t o t%ie pFriclirial, very mall i~lcleeil, being iii fact ~nerely the iriiinirn~lnl ililri~l~er rt~ilt~ired to protluc-e tlae observetl illcrerr~c~it of fusifortrl i i i t Hut I3annlan1 has provc-ci that in reality there is ,211 astonishillgly high r,ttc. of ariticlinal ciivision i~cco~rlpatlicc-l by a11 nlinost C C~L I ; L~ rate of e~ljrni~iatio~l of the t1erivativc.s.…”