Study on the Morphology of Paper-making Hemps. VI

The Distribution of Pectin in Flax Stem

Abstract

Flax stem was cut to obtain cross sections by a microtome after soaking and freezing, and then stained with a ruthenium-red solution.
Light absorption of this specimen was measured by φ3 gm spots at 180 × 180 μm² area of circumference of cambium of flax stem.
The distribution of pectin was displayed as a contour in four grades of absorption.
The absorption was measured by φ1 μm spots at 20 × 20 μm² area adjacent to a bast fiber.
The distribution of pectin was displayed as a threedimensional graph.
Based upon these results, we examined the distribution of pectin on the phloem, cortex and epidermis of flax stem.
On the other hand, flax stems without retting and retted flax fibers and xylems were extracted by ethyl alcohol-benzene mixture, and then pectin was extracted by EDTA-2Na solution.
It was determined as galactulonic acid by a carbazole-sulf uric acid method.
The neutral sugar, which was exracted with EDTA-2Na solution, was determined quantitatively by the phenol-sulfuric acid method as pentosan, by which the pectin content was corrected.
It was found that pectin exists about 4 to 5% in flax stem, most of which distributes in the adjacent area of epidermis.
About the secondary phloem, pectin exists in primary wall and middle lamella and little in the secondary wall.
Moreover, pectin exists about 1.5% in the bast, fiber and about 1.3% in the xylem after retting.