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  • Topic: Strength of materials, Cell wall, Bamboo
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A natomy and Properties of Bamboo
W. Liese
Institute of Wood Biology and Wood Preservation of the Federal Research Centre for Forestry and Forest Products,
Leuschnerstr, 91, 2050 Hamburg, Federal Republic of Germany


chymatous ground tissue. At the peripheral
zone of the culm the vascular bundles are
smaller and more numerous, in the inner
parts larger and fewer (Figs. 1, 2). Within the
culm wall the total number of vascular
bundles decreases from bottom towards the
top, while their density increases at the same
time. The culm tissue is mostly parenchyma
and the vascular bundles which are composed of vessels, sieve tubes with companion cells and fibres. The total culm comprises
about 50% parenchyma, 40% fibre, and
10% conducting tissues (vessels and sieve
tubes) with some variation according to
species. The percentage distribution and
orientation of cells show a definite pattern
within the culm, both horizontally and vertically. Parenchyma and conducting cells are more frequent in the inner third of the wall,
whereas in the outer third the percentage of
fibers is distinctly higher. In the vertical direction the amount of fibres increases from bottom to top and that of parenchyma
decreases (Fig. 3) The common practice of
leaving the upper part of a cut culm unused in
the forest is therefore a waste with regard to
its higher fibre content.
Parenchyma: The ground tissue consists
of parenchyma cells, which are mostly vertically elongated (100 x 20 urn) with short, cube-like ones interspersed in between. The
former are characterized by thicker walls with
a polylamellate structure (Fig. 4); they
become Iignified in the early stages of shoot
growth. The shorter cells have a denser cytoplasm, thinner walls and retain their cytoplasmic activity for a long time. The function of these two different types of parenchyma
cells is still unknown.
Of interest in the structure of parenchyma
walls is the occurrence of warts in many taxa

The numerous alternatives in the use of
bamboo depend on the unique properties of
its culm. In order to understand the anatomical and chemical make-up and its ensuing mechanical properties, an attempt has been
made to summarize the accessible information.

Gross anatomy: The properties of the
culm are determined by its anatomical structure. The culm consists of internodes and nodes. At the internodes, the cells are axially
oriented, whereas at the nodes, cells provide
the transverse interconnections. No radial cell
elements, such as rays, exist in the internodes. Within the nodes an intensive branching of the vessels occurs. These also bend radially inward and provide transverse conduction through the nodal diaphragms, so that all parts of the culm are interwoven. The

outer part of the culm is formed by two epidermal cell layers, the inner appearing thicker and highly lignified. The surface of outermost
cells are covered by a cutinized layer with a
wax coating. The inner parts of the culm consist of numerous sclerenchyma cells. Any lateral movement of liquids is therefore much
hindered. Pathways for penetration are thus
only the cross ends of the culm and to a much
smaller extent the sheath scars around the
The gross anatomical structure of a transverse section of any culm internode is determined by the shape, size, arrangement and number of the vascular bundles. They are
clearly contrasted b y the darker colored
sclerenchymatous tissue against the paren-

See also recent GTZ publication: Bamboos - Biology, Silvics Properties, Utilization by Liese, 1985 - Ed, ,


F igure 2 . Overview

of 6 culm s e c t i o n , Dendrocalamus

g iganteus.


Ftgure 2. Three-dlmenslonal view of culm tissue with


2 10.1826.



fi bres

vessels, phloem

like Bombusa, Cephalostachyum,

Figure 3....
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