Bambusa tuldoides

Bambusa tuldoides Munro

Trans. Linn. Soc. 26: 93 (1868).
2n = unknown

Origin and geographic distribution
B. tuldoides is a native of southern China and Vietnam. It is widely cultivated in southern China, Japan, South-East Asia and has also been introduced to Europe, the United States, Honduras, Puerto Rico and Brazil. For map click: Map85.TIF.

B. tuldoides is mainly cultivated as an ornamental, often as a hedge. When cultivated in pots or under unfavourable circumstances, the plant remains small with swollen internodes ('Buddha's belly bamboo') and is thus much treasured in bonsai and horticulture. The culms are used for farm equipment and as punting poles and scaffolding, while the splits are employed in weaving utensils and handicrafts. Young shoots are edible. Shavings of the culm cortex ('chuk yu') are used in Chinese medicine for febrile diseases, haematuria, epistaxis and infantile epilepsy.

Production and international trade
Production and trade of B. tuldoides as ornamental (bonsai) and as medicine is considerable, especially in tropical Asia, but no statistics are available.

For green culms, the nodal portion amounts to 6% of the fresh weight, the fibrous material constitutes about 60% of the culm volume. Fibre length is (1.49-)1.97(-3.17) mm. At moisture contents of 13.5% (lower parts) and 17.8% (upper parts) the following properties have been reported for culms of B. tuldoides: density 970-950 kg/m3; modulus of rupture 94.0-79.0 N/mm2 (with node), 115.2-84.0 N/mm2 (without node); compression strength parallel to grain 30.2-30.0 N/mm2 (with node), 37.8-38.3 N/mm2 (without node); tensile strength 112.0-95.8 N/mm2 (with node), 140.5-98.0 N/mm2 (without node); shear strength 50.0-59.0 N/mm2. Young shoots have an average fresh weight of 938 g before peeling, 137 g after peeling and the edible portion is 15%; they are bitter, creamy and tender when cooked; canning quality is not good.

Densely tufted, sympodial bamboo. Culm erect with slightly nodding tip, 6-10 m tall, diameter 3-5 cm near the base, wall 4-5 mm thick, glabrous, when young thinly covered with white wax; internodes 30-36 cm long, not swollen; nodes slightly swollen, lowermost 1-2 nodes with a ring of greyish silky hairs above the sheath scar. Branches frequently from the basal 1st or 2nd node upwards, branch complement few to many, with the primary branch dominant, thornless. Culm sheath caducous, glabrous or sparsely covered with a few deciduous appressed brown hairs on the outer surface, marked with 1-3 yellowish stripes towards outer margin, ribbed-striated when dried, the apex asymmetrically arched-convex and slanted along outer margin for 1/10 to 1/8 the length of the sheath; blade erect, asymmetrically triangular to narrowly triangular, acuminate and subulate, the base 3/4 as wide as the apex of the sheath, the basal margins adnate to the auricles, glabrous or sparsely covered with a few deciduous appressed brown hairs on the outer surface, rough hairy on the lower half on the inner surface; ligule 3-4 mm long, laciniate and shortly and densely fringed; auricles prominent, bearing slender bristles along the edge, slightly unequal, the larger one ovate to ovate-elliptical, undulate-wrinkled, the smaller one broadly ovate to elliptical. Young shoots glabrous. Leaf blade lanceolate to narrowly lanceolate, 10-18 cm x 1-2 cm, glabrous or sparsely pubescent toward the base above, densely soft-hairy beneath; auricles developed or lacking, narrowly ovate or falcate, bearing straight or curled bristles along the edge. Inflorescence borne on long leafless branches, consisting of groups of pseudospikelets, scattered along the branches; spikelet 2-5 cm x 2-3 mm, greenish yellow or with a purple hue, bearing 2-5 perfect florets and above these 1-2 reduced florets. Caryopsis terete, slightly curved, 8 mm x 1.5 mm, thickened and hairy at the apex.
Pot-grown specimens: culm 0.25-1.5 m tall, diameter 0.5-2 cm; internodes shortened and swollen, club- or bottle-shaped, 2-6 cm long; branch internodes also shortened and swollen.

Growth and development
Shoots of B. tuldoides emerge above the soil in the rainy season and develop to their full height in less than a year. The lateral branches often develop before the culm reaches its full height. A culm becomes mature in 2 years.
From an experiment in Canton, China, the following data are available (for a planted 1-year-old single-culm rhizome cutting): average culm height increased from 3 m in the 1st year to 12 m in the 5th year after planting, average culm diameter increased from 3 to 5.8 cm, number of new culms increased from 4 to 21, total number of culms from 4 to 73 showing a decrease in the ratio of numbers of new culms to old from 4 to 0.4. In Puerto Rico B. tuldoides rhizome cuttings developed 30-40 culms within 6 years after planting. About 10-12 years after planting, clumps were considered mature because at that age the annual number of new shoots was equal to the annual number of culms that died; maximum height was 13-14 m. In Florida (United States) a maximum culm height of 18 m has been reported.
Flowering may start at the age of 50 years. In southern China clumps usually die after flowering. Seed production is very low. Individual plants, however, may show a deviant flowering behaviour: some plants in Honduras (introduced from southern China), for example, have shown some culms in a flowering state (without producing seed) ever since their introduction, with no apparent reduction in vegetative vigour.

Other botanical information
B. tuldoides is closely related to B. pervariabilis McClure (also named 'punting pole bamboo') and B. eutuldoides McClure, both also natives of southern China. In B. pervariabilis the basal internodes are marked with yellow vertical stripes, the basal nodes are decorated with a ring of greyish silky hairs both above and below the sheath scar, and the larger auricle on a culm sheath is strongly wrinkled. In B. eutuldoides the larger auricle on a culm sheath is decurrent and four times larger than the smaller one and the basal nodes are each decorated with a ring of greyish silky hairs both above and below the sheath scar.
The dwarf form of B. tuldoides has long been considered as a form of B. ventricosa McClure, although it was known that these plants, when grown in open ground, could develop into normal plants with cylindrical internodes.

In tropical Asia B. tuldoides grows naturally at low altitudes. In the United States (California, Florida) it grows well in subtropical areas and is noted to be frost-hardy (to -7ÂșC).

B. tuldoides is propagated by rhizome and culm cuttings. In southern China the traditional preferred method of propagation is by rhizome cuttings. Individual rhizomes from the periphery of the clumps are severed at the neck and the propagules are each composed of the lower part of a single culm with the rhizome axis basal to it. The cuttings are raised in a nursery and when they have produced roots, transplanted to the field. Survival rate is almost 100%.
For large-scale propagation of B. tuldoides, culm cuttings are more appropriate.
Satisfactory results have been obtained with whole culm cuttings in Puerto Rico. It is recommended to plant 2-year-old culms. In Puerto Rico they produced in 9 months on average 7.4 plants per 3 m culm, the middle and tip zones of the culm being most productive. Branch cuttings were not successful; after 2 years in the propagation bed, bud dormancy persisted in more than 95% of the cases. Once plants have established, little care is needed. No serious diseases and pests have been reported. Harvesting of culms may start when clumps are 5-6 years old. Culms are harvested when 2-4 years old, preferably in the dry season. In Puerto Rico about 25% of the culms in a mature clump are harvested annually without adversely affecting the production of new culms; with a clump of 30 culms this means an annual production of about 7-8 culms. As yet there are no commercial plantations of B. tuldoides.

Genetic resources and breeding
No germplasm collections exist for B. tuldoides, apart from specimens present in several botanical gardens. Because fruits are occasionally found in the natural environment of this bamboo, breeding programmes could be developed, but as yet there are none.

The prospects for B. tuldoides are promising, especially as ornamental hedge plants and pot plants. It could be a good source for paper fibres because it grows fast and is easy to maintain. Research should focus on applicability of the culms, large-scale cultivation and commercialization, whereas the medicinal uses of culm-cortex shavings need further investigation.

P.P.H. But and L.C. Chia

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