1. The double refraction is displayed in varous ways in different kinds of cell walls in lignite, while this optical property is lost in bituminous coal.
2. The orientation of the axes of the indicatrix in different kinds of cell walls in lignite is the same with that of the corresponding cell wall in living plants. In the wall of tracheids, bast fibers, stone cells, and parenchymatous cells, the maximum and intermediate axes of the indicatrix are parallel to the surface of the wall and perpendicular to each other, the minumum axis being perpendicular to the surface of the wall. In the wall of cork cell, cuticle and cutinized wall the maximum axis of the indicatrix is perpendicular to the surface of the wall and the minimum axis parallel to the surface of the wall.
3. The wall of a fossil tracheidal cell and bast fiber, whose thin section is white or bright yellow under the microscope, retains the property of double refraction, while the brown colored wall or such a part of the wall does not retain this optical property. In a tracheidal cell the property of double refraction is lost much earlier in its secondary and tertiary lamellae than in the primary lamella of the wall.
4. The wall of tracheids in lignite, even in the case when the farmer retains the property of double refraction like that of living coniferous wood, scarcely shows the reaction of lignified cell wall with phloroglucin and strong hydrochloric acid, while it shows the cellulose reaction with the solution of potasium iodide of iodine and strong sulphric acid, as well as the reaction of pectin membrane with ruthenium red.
The cavity of such a tracheidal cell in lignite is generally filled with granular substance which gives the cellulose reaction with a potasium iodide of iodine solution and strong sulphurie acid.
5. The loss of the property of double refraction in the wall of tracheids in lignite is closely associated with the change of color of the cell wall, from a lighter color to a deep brown and is also accompanied by chemical changes.
6. The wall of a stone cell in lignite retains the property of double refraction far better than that of the tracheids or bast fibers. This means that the wall of stone cells undergoes their structural alteration more gradually than those of tracheids and bast fibers. From this it seems likely that stone cells will be preserved better than those tissue mentioned above in bituminous coal. However, they might not be recognized as such, as they have mostly scattered distribution among parenchymatous tissue.
7. The suberized and cutinized wall as well as cuticle do not show the phenomenon of double refraction so strongly as the wall of well preserved tracheids, bast fibers or stone cells.
8. The wall of a parenchymatous cell in lignite and bituminous coal does not retain the property of double refraction except some cases of lignified wall, where this property is retained. In the latter case, the wall retains cellulose nature, so far as the reaction of potasium iodide of iodine solution and sulphuric acid is concerned.
9. From several facts the writer has assertained, we may infer that in the process of coalification cellulose and most likely pectin substance too is largely removed in a comparatively earlier stage.
抄録全体を表示