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ORIGIN OF INTERNODAL AIR SPACES IN HIPPURIS VULGARIS L.
Author(s) -
KORN ROBERT W.
Publication year - 1976
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.1976.tb01511.x
Subject(s) - vertex (graph theory) , hexagonal crystal system , mathematics , combinatorics , space (punctuation) , air space , geometry , crystallography , computer science , chemistry , graph , operating system , engineering , aerospace engineering
SUMMARY Air spaces in the internodal regions of Hippuris vulgaris L. are separated from each other by a single file of cells, a feature which permits a geometric description of their arrangement according to the number of adjacent air spaces. This number ranges from four to eight with an average of 6.04 ± 0.29. Vertices between three adjacent air spaces are composed of either an hexagonal central cell from which three cells radiate outward, is called a cell vertex (CV) and has a frequency of 0.453, or by three pentagonal cells with a common wall point, is called a wall vertex (WV) and has a frequency of 0.547. Air spaces arise from certain three‐rayed vertices by wall separation and a subsequent series of unequal cell divisions in which the ends of cell plates only attach to walls bordering air spaces. A paper‐pencil model was devised in order to identify the critical steps of this ontogenetic sequence. One important ordering process in generating this pattern of air space arrangement is an alternating selection of vertices around cell and cell groupings which will become air spaces. A second ordering feature is the positioning of cell plates in order that they attach only to facets bordering air spaces. This model produces the features of spaces separated by a single row of cells and the ratio of the two types of vertices cited above but only approximates the number of cells around a space. It has been demonstrated here that walls of a cell can influence each other through some type of inhibition, and as a morphogenetic mechanism in general, it may play an important role in other cases of tissue development.