MCKOWN, ATHENA D.1*, ORIANA PEGORARO2, and DAVID D. CASS1. 1Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9 Canada; 24 Keating Pt., St. Albert, AB Canada. - Band plasmolysis in leaf epidermal cells of Clivia miniata (Amaryllidaceae).
Leaf epidermal cells of Clivia miniata Regel have strongly
thickened outer tangential walls, sizeable cuticles and epicuticular
wax deposits, features associated with survival in hot, dry climates.
These cells also exhibit band plasmolysis, shown using a variety of
cytological methods, and is a feature that has not been previously
associated with epidermis. Results were best obtained by staining with
the membrane fluorochrome RH414 (Molecular Probes) and followed by
treatment in solutions of 0.8 M mannitol. Membrane adherence was seen
on a thin, wavy anticlinal partition between epidermal cells. Attempts
to stain this portion of cell wall with lipid binding reagents such as
berberine, a stain commonly used for examining root exodermis and
endodermis, were unsuccessful. Use of the apoplastic tracer
pyrenetrisulfonate (PTS) revealed that PTS is not fully mobile in the
thickened portion of anticlinal wall adjacent to the site of membrane
adherence. A xerophytic taxon exhibiting this phenomenon suggests that
its leaf epidermal cells possess a barrier to apoplastic water
movement, forcing water into the symplastic pathway where greater
cytoplasmic control might be realized.
Key words: Amaryllidaceae, band plasmolysis, Clivia miniata, epidermis, plasma membrane.