The Effects of Cell Division on Three‐dimensional Cell Shape in Aloe Barbadensis

Polygonal Aspects of Cell Faces. I. Pentagons and Hexagons as Prevailing Types

“…MATERIALS AND METHODs-The data, taken from the cited literature, were used in an earlier study (Wheeler, 1958). Reference numbers, assigned to them there, are retained in the present 1 Received for publication July 26, 1961. paper, despite the different arrangement of samples.…”

“…Statistical analyses have not been applied in this, or in the subsequent papers of this series. Objections to the use of statistics in connection with the utilization of such data in these particular problems were outlined in a previous publication (Wheeler, 1958). Since the analyses in these studies are of necessity kept at low level, statistical evaluations, even if justified, would be inappropriate.…”

“…Since faces will be both cut and touched when a cell divides, it is necessary to determine how the percentages of 4-, of 5-, and of 6-gons are affected by these 2 division effects. Papers by Lewis (1950), by Matzke and Duffy (1956), and by Wheeler (1958) include diagrams of cut and of touched faces; therefore, only those diagrams necessary for the discussion will be included here.…”

“…The directions and the relative rates of cell division strongly influence the kinds of faces found on a dividing cell and on its immediate neighbors. Some of these effects have been discussed in detail (Wheeler, 1958). Intrusive growth (see Esau, 1953, for a general discussion) also alters cell faces and their relationships, but this phenomenon apparently is not operating in any of the samples of Table 1, with the possible exception of no.…”

“…These and other polygon types result from cell division (some faces of sample 20 may be exceptional as noted above). Furthermore, each author indicates that the following conditions usually, although not always, prevail: (1) cells adjacent to each other do not differ much in size (see condition 3); (2) elongated cells lie parallel with neighboring cells, i.e., new division walls are neither oblique nor perpendicular, but are parallel to each other (the former 2 orientations give highly atypical face distributions as shown by Siegerman [1951], by Wheeler [1955,…”