Axial thin-walled tissue thin-walled tissue includes two types of systems

Thin-walled tissue (wood ray parenchyma) and axial thin-walled tissue in the radial direction of the tube. Axial parenchyma refers to the original cells derived from the spindle-forming layer. The axial thin-walled tissue of broad-leaved trees is important in identifying wood and is more clear after the water is wet. The secreted or secreted parenchyma cells around the intercellular tract are usually not viewed as axial thin-walled tissue.

(1) obviousness

Observed on three cut planes, the cross section should be the main one, sometimes it is more significant under low magnification. Not visible or unclear under the magnifying glass, such as kapok, holly, etc. Visible or clear under the magnifying glass, such as maple, persimmon and so on. Visible or clear under the naked eye, such as genus, Castanea and so on.

(2) Type

The axial thin-walled structure of broad-leaved trees is one of the important wood features on the cross-section. Those who are away from the pipe hole are called the pipe type. The attached or surrounding tube hole is called the fistula type. There are also some types of rounds in the tube type, which are often of several types or of a certain type in a certain specimen.

1. Off-tube thin-walled tissue: refers to the axial thin-walled tissue in the case of mode, does not depend on the tube hole or catheter, the wheel boundary, the scattered, the scattered polymer and the band.

(1) Wheel boundary: Located at the beginning or end of the seasonal growth, that is, at the growth wheel alone or forming a different width and a slightly continuous band, this feature should also be supported on the radial section.

(2) Star-shaped: refers to a single bundle of thin-walled tissue or parenchyma cells, which are seen in the cross-section and irregularly, like the sky stars scattered between the fibers. This type is often not visible under the naked eye and under the microscope.

(3) Star-dispersed polymerization: refers to the aggregated thin-walled structure of the star. On the cross-section, there is a tendency for the wooden rays to form a short string. Mesh refers to the ray and thin-walled tissue lines or bands that form a network pattern that is slightly equidistant, ie square, square. Viewed from the cross-section, there is a tendency to gather into short strings between the rays, such as the genus Dioscorea.

(4) Off-tube strip: refers to the band-shaped thin-walled tissue, in the case of mode, does not depend on the catheter, such as walnuts. 1 Broad-band (used under the magnifying glass) The thin-walled belt is equal or wider than the spaced fiber strips, such as linden, eucalyptus, etc. 2 Under the microscope, the width of the band is usually expressed directly by the number of cells.

2. Tube-type thin-walled tissue: refers to the axial thin-walled tissue and the catheter and the vascular tube. In the mode, the tube hole or the catheter is attached. It has a sparse-tube shape, a loop-shaped bundle, a wing-like shape, and a poly-wing shape. ).

(1) sparse tubular (circular tubular, slightly annular): refers to the incomplete sheath surrounding the catheter or only occasionally appearing beside the catheter, not visible under the naked eye or magnifying glass, such as , Du Ying, genus, horse chestnut and so on.

(2) Loop bundle shape: refers to the thin wall tissue of the fistula tube around the circumference of the catheter to form sheaths of different widths, which are round or oval on the transverse plane, such as citron.

(3) Wing shape: refers to the thin-walled tissue of the fistula is wing-like lateral extension. This feature also includes a unilateral wing (thin wall tissue is limited to the outside or inside of the catheter), such as Paulownia.

(4) Poly-wing or belt-like: refers to the connected wing-shaped thin-walled structure, which is a string or a diagonal belt on the transverse section. The poly wing is similar to the fistula band, except that the former does not have the latter rule. According to the situation of the polywing, it is divided into a poly-winged and a sacral band (refers to the connected wing-shaped thin-walled tissue, which is formed on the cross-cut surface to form a regular string or oblique band, such as Sapindus mukurossi, etc. ). 1 Broadband (used under the magnifying glass) The thin-walled belt is equal or wider than the spaced fiber belt. Such as linden, eucalyptus and so on. 2 Under the microscope, the width of the tape is usually expressed directly by the number of cells.

(5) Unilateral ring thin-walled tissue: 1 finger ring thin-walled tissue is limited to the outer side of the catheter (distal axis) or the inner side (paraxial axis). 2 Such parenchyma can be further divided into a single-sided tubular shape, a single-sided wing and a single-sided poly-wing.

3. Band-shaped thin-walled tissue: the axial thin-walled tissue is concentric and the cross-section under the magnifying glass, but it is difficult to distinguish it from the strip or the tube (poly-wing). It is a band-shaped thin-walled tissue such as Dalbergia.

Practically, it has been proposed that a bandwidth of 0.05 mm or more is a strip shape; a bandwidth of 0.05 mm or less is called a thin line.

4. Two descriptive nouns (mainly used for the separation type)

(1) Reticulated parenchyma: refers to the network pattern formed on the cross-section, such as pecans, when the rays intersect with the axially thin-walled tissue strips or lines of the distance gauge, when they are almost equidistant equidistant. Carya cathayensis) and so on.

(2) Ladder-like thin-walled tissue: refers to the axial thin-walled tissue band or line of the ray and distance. When the latter is obviously narrower than the ray, it is almost rectangular, and the ladder-like pattern formed on the transverse plane, such as Mezzettia lepttila and so on.

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