Premium
SIMULATIONS OF CELL DIMENSIONS IN SHOOT APICAL MERISTEMS: IMPLICATIONS CONCERNING ZONATE APICES
Author(s) -
Niklas Karl J.,
Mauseth James D.
Publication year - 1980
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1980.tb07702.x
Subject(s) - apical cell , meristem , biology , geometry , aspect ratio (aeronautics) , surface (topology) , helicoid , anatomy , physics , botany , shoot , cell , mathematics , genetics , optoelectronics
Surface areas, differential curvatures, volumes, and dimensions of cell‐like units were described for various geometric shapes approaching the morphology of shoot apical meristems (SAM) in vascular plants. Geometric relationships are given in both graphic and dynamic simulations of shape. If the surface of the SAM is described by the revolution of a parabolic, hyperbolic, or circular function, then the greatest change in the surface areas or volumes of equally spaced transverse sections will occur in those regions showing the greatest differential in surface curvature. Subdivision of the SAM volume into cell‐like units leads to quantitative expressions of changes in “cell” length to width and width to depth (aspect) ratios. Dependent upon the geometry of the SAM, differential expressions of aspect ratios may lead to a zonate pattern within the SAM corresponding to a central‐mother‐cell zone (CMC), a peripheral zone (PZ), and a pith‐rib meristem (PRM). The boundary between the PRM and PZ, as seen in median longitudinal section, is a geometric consequence of the deployment of cells with aspect ratios best suited to occupy the entire SAM volume. The number of cell‐like lineages, L, in the SAM may be expressed by the aspect ratio of cells in longitudinal section, n x‐y , such that for the PRM and PZ, L = k 1 n x‐y ‐5.38 and L = k 2 n x‐y 3.18 , respectively. Cellular patterns seen in the “corpus” of the SAM may not, therefore, be the a priori result of physiologically distinct populations of cells. Computer simulations are discussed within the data set derived from a study of the SAM of cacti.