ISSN:
1615-6102
Keywords:
Abscission
;
Actin filaments
;
Cytokinesis
;
Immunocytochemistry
;
Microtubules
;
Moss protonema
;
Preprophase band
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary When grown on nutrient agar, protonemata ofBryum tenuisetum produce aerial filaments containing several abscission or tmema cells (TC). Basipetal migration of the nucleus and some of the chloroplasts signals the onset of TC formation. This is followed by the creation of a plastid-free zone at the base of the mother cell. The ensuing cytokinesis produces a very short aplastidic TC. This expands without the deposition of new wall material. Eventually the wall ruptures around the equator thus disrupting the protonemal filament. The site of wall breakdown is marked by a narrow band of cortical cytoplasm containing colocalized circumferential rings of actin filaments and microtubules. A transverse band of microtubules appears at the extreme basal end of the tmema mother cell. This band, which is not colocalized with actin filaments, migrates distally over the surface of the nucleus. Intimate spatial and developmental correlations suggest that this transverse array of the microtubules has a key role in excluding plastids from the TC. It is therefore considered not to be homologous with a preprophase band.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01379048
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