Anatomical Features Of Radial Resin Canals In Pinus Densiflora

Abstract

We investigated radial resin canals in Pinus densiflora by means of serial tangential sections taken from phloem to xylem through the cambium. The canals were found within fusiform rays in both phloem and xylem. The ducts were closed in the cambial zone, but opened at widely differing distances from the cambium among individual radial resin canals, ranging from 120 to 340 μm on the phloem side and from 260 to 640 μm on the xylem side. Further, the ducts were not open continuously on both sides. The average number of radial resin canals in the tangential plane was 0.76/mm2. In the cambial zone, central cells of fusiform rays which might develop into epithelial cells later, were smaller and more deeply stained than the surrounding ray initial cells, allowing them to be identified at the initial stage. Two or more radial resin canals situated nearby each other were connected through an axial resin canal.