ISSN:
1615-6102
Schlagwort(e):
Autofluorescence
;
Cell wall
;
Cotton fibres
;
Ovule culturein vitro
;
Suberin
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Biologie
Notizen:
Summary The secondary cell walls of fibres of the green lint variety of cotton are strongly autofluorescent and stain with both Sudan III and osmium tetroxide. In the electron microscope thin sections of aldehydeosmium fixed fibres show concentric, osmiophilic layers in the walls, each separated by cellulosic material. The number of these layers corresponds approximately to the number of days of secondary wall formation suggesting a periodic deposition. At higher magnifications each osmiophilic layer consists of several alternating electron opaque and electron translucent lamellae with a periodicity of about 4.2 nm. Ovules of the same variety culturedin vitro, in the dark and at constant temperature, also develop green fibres exhibiting the same ultrastructural features. Chemical analysis of the isolated fibre cell walls confirmed the presence of suberin, the dominant monomer being 22-hydroxydocosanoic acid (65% of the total monomeric mixture). These findings strongly suggest that suberin, as well as waxes, are associated with the formation of the concentric rings of lamellated lipid material which characterise the walls of green lint cotton fibres. A similar polymeric lipid also occurs in green lint epidermal cells that do not form fibres. However, in the white lint variety this polymer is restricted to the outer part of non-fibre forming epidermal cells and to the lateral walls at the base of the fibres.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF01281823
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