RADIAL STRIATION OF THE S2 LAYER IN MILD COMPRESSION WOOD TRACHEIDS OF PINUS-RADIATA

The fine structure of the tracheid walls in Pinus radiata mild compres sion wood was examined by field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). On transverse-fra ctured surfaces the S-2 layer of tracheid walls exhibited distinct rad ial structures when observed with the FE-SEM. The TEM observations of ultrathin sections of samples from similar regions showed the S-2 laye r with radial striations, corresponding in their direction to the radi al structures seen with the FE-SEM. The observations are discussed in relation to the information on the structure and composition of compre ssion wood cells.