Ultrastructural Observations on the Distribution of the Intra-and Intercellular Cytoskeleton of the Endosperm Cells in Triticum aestivum

By means of Triton X-l00 extraction and DGD (diethylene glycol distearate) embedment-free section method the distribution pattern and characteristics of intra- and intercellular cytoskeleton of endosperm cells of Triticum aestivum L. were studied with electron microscopy. Threedimensional architecture of the cytoskeleton could be recognized as a meshwork mainly composed of microtubules (MT) and microfilaments (MF). Attention was stressed on the interface of the adjoining cytoskeletal frameworks where an attractive phenomenon observed was that the MF extruding from the surface of the cytoskeleton often traversed the whole wall boundary and connected the neighbouring frameworks into an entity. In the endosperm tissue two types of transcellular MF distribution could be distinguished, the MF in bundles traversing the enlarged intercellular channels and the MF individually penetrating the wall boundary; that seemed to coordinate with the co-presence of normal and modified plasmodesmata in the same wall. The above observations demonstrated the intercellular cytoskeletal continuity within the symplast and confirmed that the MF was the main constituent of the traversing cytoplasmic strands, the possibility of MF being organized as a structural element of the normal plasmodesmata was also discussed.