ISSN:
1615-6102
Keywords:
Asymmetric cytokinesis
;
Cell differentiation
;
Localized Ca2+ accumulation
;
Nuclear migration
;
Onoclea
;
Vittaria
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary In gemmae ofVittaria graminifolia and prothallia ofOnoclea sensibilis, cell differentiation is initiated by nuclear migration and geometrically asymmetric cell division. The small daughter cells inVittaria develop into antheridia in the presence of gibberellic acid or into rhizoids or new prothallia in its absence. Antheridial differentiation from asymmetric division is induced inOnoclea byPteridium antheridiogen, whereas rhizoid or vegetative cell formation occurs in its absence. Although asymmetric cytokinesis initiates differentiation, it does not in itself determine the developmental fate of the smaller cell. Several histochemical techniques demonstrate that prior to nuclear migration and cell division, Ca2+ accumulates in the cytoplasm and wall of the cell at the site where asymmetric division will occur, regardless of the developmental fate of the small cell. The cytoplasmic localization of Ca2+ appears to reflect a mobilization of Ca2+ from within the cell that eventually moves into the cell wall. We propose that this internal accumulation of Ca2+ leads to a localized decrease in cytosolic [Ca2+] which in turn may regulate developmental events such as nuclear migration.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01276357
