ISSN:
1615-6102
Schlagwort(e):
Microtubules
;
Mitosis
;
Plastids
;
Preprophase Band
;
Isoetes
;
Selaginella
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Biologie
Notizen:
Summary Ultrastructural observations on monoplastidic root tip cells ofIsoetes andSelaginella demonstrate two important phenomena associated with preprophasic preparation for mitotic cell division, 1. the preprophase band and 2. precise orientation of the dividing plastid relative to the preprophase band. Both of these phenomena accurately predict the future plane of cell division. The plastid divides in a plane parallel to the spindle and each cell inherits a single plastid which caps the telophase nucleus. When succesive transverse divisions occur, the plastid migrates prior to prophase from a position near an old transverse wall to a lateral position in the cell. The plastid is oriented with its median constriction precisely intersected by the plane of the preprophase band. When a longitudinal division follows a transverse division, the plastid remains in its position adjacent to an old transverse wall where it is bisected by the plane of the longitudinally oriented preprophase band microtubules.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF01283580
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