On intercellular spaces in the xylem ray parenchyma of Picea abies

The radially-running intercellular spaces in ray parenchyma of adult xylem of Picea abies were studied with the light microscope and with the scanning electron microscope. Special attention was paid to radial continuity and dimensions of these channels, and also to the blind pits in the parenchymatous cell walls opposite these intercellular spaces. In locally very thick-walled ray parenchyma, an aberrant type of blind pitting seems to occur.