ISSN:
1615-6102
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary The loose “cuticles” of the cells of wilted staminal hairs ofTradescantia virginica do not contain cellulose at all; (compare fig. 6 with fig. 5 and 7). They exhibit a positive rodlet birefringence with reference to the cell axis, which is probably due to cuticular folds and to longitudinal spaces inside the cuticle. There is a faint negative intrinsic birefringence in normal as well as in dewaxed cuticles, suggesting the presence of chemically bound, radially oriented chain molecules in these longitudinal spaces. (See table 1 and fig. 8.) According to the oblique extinction of single cell walls between crossed nicols and according to the fact that the cell wall, if torn, sometimes shows unwinding spirals (fig. 1, 2) the fibrillar structure of the cellulose cell wall in many cells must be oriented according to a flat Z- or S-spiral. In other cells this structure is predominantly transverse. Electron micrographs show that in addition to the more or less transversely oriented predominant inner layer of the cell wall, there is an outer layer with more or less isotropic, fibrillar structure (fig. 10, 11, 12). This is explained by assuming that the outer layer is in a less favourable position for intussusception of new fibrils during growth than the inner one, which will cause a reversion of the originally transverse fibril orientation in the former. The same layer structure is already found in very young cells, still showing cell division; (fig. 13, 14). The fibril thickness is about 100 Å. The cell walls separating the cells of the staminal hairs are perforated by some 800 holes of about 0,1μ diameter, which probably contained plasmodesmata, (fig. 15, 16).
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01247932
Permalink