Abroma augusta (L.) L.f.

Family

Sterculiaceae (APG: Malvaceae)

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Chromosome number

2n = 16, 20, 22

Synonyms

Abroma fastuosum Jacq. (1776, nom. illeg.), Theobroma augusta L. (1776), Abroma fastuosa R.Br. (1812), Abroma mollis DC. (1824).

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Vernacular names

Devil’s cotton, perennial Indian hemp, abroma (En). Abrome, abrome royal (Fr). Abroma (Po).

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Origin and geographic distribution

Abroma augusta is distributed from India throughout South-East Asia to southern China, northern Australia and the Solomon Islands. It is cultivated in India and sometimes in South-East Asia. It has also been grown on a small scale in tropical Africa, especially in DR Congo and Uganda; it has also been introduced into West Africa and Tanzania. The present distribution of Abroma augusta in tropical Africa is unclear.

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Uses

In East Africa the bast fibre has locally been used for making ropes, fishing nets and hammocks. In Asia the fibre is used for a range of purposes, including rope, twine, fishing lines, nets and clothing. Rope made of it is valued for its strength and is used for clotheslines, since it does not stain. Dyed, very fine fibres are used as false hair in Sumatra. In the Philippines Abroma augusta is considered a substitute for rattan, and bark splits are made into products such as potholders, baskets and trays.
In India and New Guinea the leaves are occasionally eaten. The seed is edible as well. The species has been proposed for reforestation in Asia, as it is able to control cogon grass (Imperata cylindrica (L.) Raeusch.). It is sometimes grown as an ornamental.
Abroma augusta is widely used in traditional medicine in India, Bangladesh and other Asian countries, especially for the treatment of menstruation disorders (root, root bark, stem, heartwood, stem bark, leaves, flower, whole plant), gonorrhoea (root, root bark, heartwood, stems, leaves), diabetes (root, bark, leaves, whole plant) and skin problems (root, leaf juice, seed oil, whole plant), and as an antifertility agent (root) and aphrodisiac (root, stem, leaves, whole plant).

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Production and international trade

Statistics on production and trade are not available.

Properties

The fibre is located in the secondary phloem. The fibre content of fresh, defoliated stems is (3–)4–8(–9)%. The ultimate fibre cells are (1.4–)2–3(–6.4) mm long and (6–)12–20(–39) μm wide, with the lumen diameter being about one third of the total diameter. The ends of the ultimate fibre cells are tapered and sometimes forked. The fibre contains 75–78% cellulose and c. 7% lignin. The extracted fibres, consisting of connected ultimate fibre cells, are 0.5–2.5 m long. Properly prepared fibre is fine, creamy white to golden brown, lustrous, rather silky in appearance, strong and supple. However, the fibre bundles are irregular and coarse and it is difficult to separate the bundles into individual strands. The fibre is difficult to spin, but can be used mixed with jute in the manufacture of hessian. On its own it is considered suitable for making twines and yarn for sack-cloth and it can serve as a substitute for jute (Corchorus spp.) and hemp (Cannabis sativa L.) fibre. In DR Congo the average breaking length of fibre obtained after retting of fresh stems in running water ranged from 26 km to 36 km, with an average of 30.7 km. The breaking length of fibre from Rwanda measured in the 1950s was 31.2 km. An important obstacle to the use of Abroma augusta as a source of fibre is that the plants are covered with irritating hairs, making handling very unpleasant and causing dermatitis in sensitive persons.
Aqueous extracts of the root have shown in-vivo hypoglycaemic and hypolipidemic effects in alloxan-diabetic rats, galactotrophic effects in lactating rats, and oxytocic activity. Ethanol extracts of the root showed in-vivo wound healing activity in rats. Petroleum ether, ethanol and chloroform extracts of the root had abortifacient activity. Methanolic extracts of the root bark, stem bark and leaves showed antibacterial activity. Methanolic leaf extracts have shown in-vivo anti-diabetic activity in alloxan-diabetic rats and in-vitro antioxidant activity, but also toxicity in the brine shrimp bioassay. The seed oil has shown phytotoxic activity against Lemna aequinoctialis Welve and moderate antifungal activity against Trichophyton schoenleinii and Microsporum canis; it did not show antibacterial or insecticidal effects, nor toxicity in the brine shrimp bioassay.
Compounds isolated include the alkaloid abromin, choline, β-sitosterol, stigmasterol and friedelin from the root, β-sitosterol and friedelin from the stem bark, β-sitosterol from the heartwood, and taraxerol, β-sitosterol-acetate and octacosanol from the leaves. The seed yields 20% oil containing palmitic acid (14%), stearic acid (4%), oleic acid (9%) and linoleic acid (72%). The oil does not contain cyclopropenoid acids.

Description

Erect shrub or small tree up to 10 m tall, up to 2–4 m tall when cultivated, normally branching at 1–2 m height but due to coppicing often multistemmed from the base; stem and branches with tenacious bark, all parts often with prickly-pointed, irritating, stellate hairs and sometimes also with glandular hairs; orthotropic branches usually remaining vegetative, flowering branches usually plagiotropic. Leaves alternate, simple, highly variable but two main forms exist (heterophylly): lobed (often on orthotropic branches) or unlobed (often on plagiotropic branches); lobed form with petiole up to 40 cm long, blade 3–5-lobed, cordate-ovate in outline, up to 30–40 cm × 30–40 cm, base palmately 3–7-veined, margin irregularly dentate; unlobed form with petiole up to 1.5 cm long, blade lanceolate, 10–23 cm × 9–12 cm, cordate at base, margin denticulate, palmate-pinnately veined. Inflorescence a leaf-opposed or terminal 1(–4)-flowered cyme; peduncle 1–3 cm long; bracts 6–8 mm long. Flowers bisexual, pendent, 3–5 cm in diameter, 5-merous; bracteoles 2, pedicel 1–3.5 cm long, articulate; calyx deeply divided into 5 lobes, lobes entire, triangular, 15–20 mm × 6 mm, greenish; petals 5, spoon-shaped, 2–3.5 cm × 1 cm, base concave and white, blade dark purple, red or yellow, ciliate; staminal tube short, apically with 5 fascicles of anthers alternating with 5 petal-like staminodes, each fascicle with 3(–4) anthers; ovary superior, 2–3 mm long, 5-lobed, 5-celled, style 1–2.5 mm long, with 5 branches. Fruit an obconical capsule 4–5 cm × 3–4 cm, base rounded, top truncate, 5-winged and angled, sometimes beaked, enveloped by the slightly enlarged calyx, densely prickly hairy, apical portion loculicidal, lateral parts septicidally dehiscent, with numerous seeds. Seed cylindrical to obovoid, 3–4 mm × 2 mm, without wings or aril, black. Seedling with epigeal germination

Other botanical information

The number of taxa in the Abroma augusta complex is disputed. Based on the presence or absence of prickles on the stems and branches, the colour of the flowers and the number of seeds in the capsules up to 3 species have been distinguished: Abroma augusta, unarmed, flowers red, capsule with more than 200 seeds; Abroma mollis DC., unarmed, flowers yellow, capsule with more than 200 seeds; and Abroma fastuosa R.Br., armed, capsules with 50–60 seeds, only occurring in Madagascar. Here the view is accepted that there is only one widespread, highly variable species, but a critical revision is needed.

Anatomy

The bast fibres occur in wedge-shaped groups of bundles. The fibre bundles are irregular and coarse, mostly rectangular in transverse section. The number of fibre bundle layers per wedge is 8–11, with c. 21 cells per bundle.

Growth and development

Abroma augusta is protogynous and allogamous, with pollination by wind and insects. The flowers fall off at the latest one day after opening. It normally spreads by seed, but when the stems are cut, new shoots may emerge from the buds in the axils of the leaf scars at the base of the plant. Suckers may also develop from lateral roots running parallel to the soil surface. In DR Congo flowering occurs 100–120 days after sowing, and the fruits ripen 60–90 days later.

Ecology

Abroma augusta can be grown in areas with an average annual temperature above 15°C, and an average annual rainfall of at least 1000 mm. An average annual temperature of 25–30°C and a well-distributed average annual rainfall of 1800–2500 mm are optimal. The species is not suitable for areas with a marked dry season. It is not frost-hardy and it is not found at altitudes above 1200 m. Abroma augusta is a short-day plant. The best soils are fertile alluvials with a good structure and good drainage, as it does not tolerate waterlogging for a long period. However, it will also survive and grow when soil conditions are less favourable.
The natural distribution area of Abroma augusta is characterized by mean daily temperatures of 27–30 °C in the hottest months, an average annual rainfall of at least 1500 mm and a high relative humidity. Where growing wild, the species grows in tufts or thickets, secondary forest, waste places and village borders and along railways and roads, seemingly preferring forest edges and banks of water courses.

Propagation and planting

Abroma augusta can be propagated by seed, stem cuttings or suckers emerging from lateral roots. The 1000-seed weight is c. 6 g. For seed propagation fresh material should be used, as seeds show low germination rates and lose viability rather quickly. Soaking in water for 24–48 hours improves germination, and germination of soaked seeds normally starts within 9 days. At a temperature of 33°C germination is more rapid and the final germination percentage higher than at 20–25°C.
Seeds can be sown directly in the field or in nurseries for planting out. In the latter case, the best results in Uganda were obtained by using seedlings c. 30 cm tall, cut back to 15 cm before being planted out. A sowing depth of 7 cm gave better results than less deep sowing. Soil preparation before sowing is desirable, and farm manure or green manure may be incorporated. When plants are planted too wide apart, they branch too much, but with too narrow spacing it is difficult to obtain uniform stands. In spacing trials in DR Congo spacings of 0.4 m × 0.4 m or 1 m × 0.2 m gave the highest fibre yields.

Management

In cultivated Abroma augusta normally only 2 weedings are necessary, the first at about 20–30 days after sowing, the second about 1 month later.

Diseases and pests

In Uganda Abroma augusta has proven very susceptible to Verticillium wilt, which may kill the plant or lead to stunted growth.

Harvesting

The stems are harvested at flowering, when the fibre quality is optimal. However, if only coarse fibre suitable for cordage is to be obtained, harvesting may be done later, resulting in higher yields but a more lignified product. The stems are coppiced at about 25 cm above the ground, as cutting at a lower height may endanger regrowth. Vigorous regrowth normally occurs, with 2–3(–5) new shoots per plant. Up to 4 harvests per year may be possible, but 1–2 harvests is most common. On good soils the plants may be harvested for 3 years, but on poor soils yields decrease sooner.

Yield

Fibre yields depend on a number of factors including climate, soil and whether wild or cultivated plants are involved. The average dry fibre yield for the whole economic life of a planted crop has been estimated at 700–1000 kg/ha. Abroma augusta can yield 250 kg/ha seed per year.

Handling after harvest

The fibre bundles can be extracted by retting the whole stems (fresh or dried) or only the bark (fresh or dried). Where only the bark is retted, it is manually removed in ribbons from the stems immediately after the harvest, when the bark is easiest to remove. Drying of stems or bark may be done in the open field or under shelters. Properly dried bark can be stored for several months. The required retting period depends on prevailing conditions, especially the temperature and nature of the water used (e.g. stagnant or running). Retting of stems normally takes 7–15 days, with older stems needing a longer retting period than young ones. Retting of fresh bark ribbons takes about 11 days, and retting of dry bark ribbons about 13 days. The fresh bark yields about 13% dry fibre on retting, the dry bark about 45%. After retting, the fibre is usually washed, dried and rubbed or beaten to make it supple and to separate the strands. Over-drying makes the fibre brittle.

Genetic resources and breeding

No germplasm collections of Abroma augusta are known to exist.

Breeding

Priorities in any future breeding programme should be higher yields and the development of cultivars without irritating hairs.

Prospects

Abroma augusta yields a strong fibre suitable for cordage and will remain useful for this purpose locally. It has been proposed from time to time as a promising perennial source of bast fibre, avoiding the labour and costs involved in growing annual bast fibre crops. However, the presence of irritating hairs all over the plant and the relatively low yields make an increase in the importance of its fibre, in Asia as well as in Africa, very unlikely.

Major references

• Aguilar, N.O., Jansen, P.C.M. & Brink, M., 2003. Abroma augusta (L.) L.f. In: Brink, M. & Escobin, R.P. (Editors). Plant Resources of South-East Asia No 17. Fibre plants. Backhuys Publishers, Leiden, Netherlands. pp. 59–62.
• Capot, J., de Meulemeester, D., Brynaert, J. & Raes, G., 1953. Recherches sur une plante à fibres: l’Abroma augusta L.f. Publications de l’Institut National pour l’Étude Agronomique du Congo Belge (INEAC). Série technique No 42. 113 pp.
• CSIR, 1985. The wealth of India. A dictionary of Indian raw materials and industrial products. Raw materials. Revised Edition. Volume 1. Publications and Information Directorate, New Delhi, India. 513 pp.
• Germain, R. & Bamps, P., 1963. Sterculiaceae. In: Robyns, W., Staner, P., Demaret, F., Germain, R., Gilbert, G., Hauman, L., Homès, M., Jurion, F., Lebrun, J., Vanden Abeele, M. & Boutique, R. (Editors). Flore du Congo belge et du Ruanda-Urundi. Spermatophytes. Volume 10. Institut National pour l’Étude Agronomique du Congo belge, Brussels, Belgium. pp. 205–316.
• Greenway, P.J., 1950. Vegetable fibres and flosses in East Africa. The East African Agricultural Journal 15(3): 146–153.
• Kirby, R.H., 1948. Abroma augusta fibre from Uganda. Bulletin of the Imperial Institute 46: 192–197.
• Kirby, R.H., 1963. Vegetable fibres: botany, cultivation, and utilization. Leonard Hill, London, United Kingdom & Interscience Publishers, New York, United States. 464 pp.
• Lejeune, J.B.H., 1953. Contribution à l'étude des plantes à fibres, à Rubona. Bulletin Agricole du Congo Belge 44: 743–772.
• National Medicinal Plants Board, 2008. Agro-techniques of selected medicinal plants. Vol. 1. TERI Press, New Delhi, India. 240 pp.
• Rahmatullah, M., Sadeak, S.M.I., Bachar, S.C., Hossain, M.T., Al Mamun, A., Montaha, Jahan, N., Chowdhury, M.H., Jahan, R., Nasrin, D., Rahman, M. & Rahman, S., 2010. Brine shrimp toxicity study of different Bangladeshi medicinal plants. Advances in Natural and Applied Sciences 4(2): 163–173.

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Other references

• Alam, M.S., Chopra, N., Ali, M. & Niwa, M., 1996. Oleanen and stigmasterol derivatives from Ambroma augusta. Phytochemistry 41(4): 1197–1200.
• Basumatary, S.K., Ahmed, M. & Deka, S.P., 2004. Some medicinal plant leaves used by Boro (tribal) people of Goalpara district, Assam. Natural Product Radiance 3(2): 88–90.
• Burkill, H.M., 2000. The useful plants of West Tropical Africa. 2nd Edition. Volume 5, Families S–Z, Addenda. Royal Botanic Gardens, Kew, Richmond, United Kingdom. 686 pp.
• Cheek, M. & Dorr, L., 2007. Sterculiaceae. In: Beentje, H.J. & Ghazanfar, S.A. (Editors). Flora of Tropical East Africa. Royal Botanic Gardens, Kew, Richmond, United Kingdom. 134 pp.
• d’Oliveira Feijão, R., 1960. Elucidário fitológico. Plantas vulgares de Portugal continental, insular e ultramarino. Classificão, nomes vernáculos e aplicações. Volume 1, A–H. Instituto Botânico de Lisboa, Lisbon, Portugal. 472 pp.
• Hussain, H.E.M.A., Jamil, K. & Rao, M., 2001. Preliminary studies on the hypoglycaemic effect of Abroma augusta in alloxan diabetic rats. Indian. Journal of Clinical Biochemistry16(1): 77– 80.
• Jacques-Félix, H., 1935. Recherches de cultures annexes à la culture bananière pour la Guinée Française. Deux plantes à fibres. Revue de Botanique Appliquée & d’Agriculture Tropicale 15: 243–251.
• Khan, T., Ahmad, W., Bashir, S., Iqbal, Z., Ahmad, B., Ahmad, M., Nisarullah, Arfan, M. & Shaheen, F., 2003. Biological and pharmacological properties of Abroma augusta Linn. seed oil. Pakistan Journal of Biological Sciences 6(13): 1142–1144.
• Kirtikar, K.R. & Basu, B.D., 1918. Indian Medicinal Plants. Sudhindra Nath, Basu, Bahadar Ganj Allahabad.
• Maiti, R., 1997. World fiber crops. Science Publishers, Enfield, New Hampshire, United States. 208 pp.
• Maiti, R.K., 1979. A study of the microscopic structure of the fiber strands of common Indian bast fibers and its economic implications. Economic Botany 33(1): 78–87.
• Maiti, R.K. & Chakravarty, K., 1977. A comparative study of yield components and quality of common Indian bast fibres. Economic Botany 31: 55–60.
• Medina, J.C., 1959. Plantas fibrosas da flora mundial. Instituto Agronômico Campinas, Sao Paulo, Brazil. 913 pp.
• Mukherjee, K.S. & Badruddoja, S., 1977. Chemical investigation of the heartwood of Abroma augusta Linn. f. Current Science 47(9): 301.
• Nahar, L., Ripa, F.A., Rokonuzzaman, M. & Al-Bari, M.A.A., 2009. Investigation on antioxidant activities of six indigenous plants of Bangladesh. Journal of Applied Sciences Research 5(12): 2285–2288.
• Nahar, L., Ripa, F.A., Rokonuzzaman, M., Zulfiker, A.H.M., Haque, M. & Islam, K.M.S., 2010. Comparative study of antidiabetic effect of Abroma augusta and Syzygium cumini on alloxan induced diabetic rat. Agriculture and Biology Journal of North America 1(6): 1268–1272.
• Norman, A.G., 1937. The composition of some less common vegetable fibres. Biochemical Journal 31: 1575–1578.
• Shanbhag, T., Dattachaudhuri, A., Shenoy, S. & Bairy, K.L., 2009. Wound healing activity of Abroma augusta in Wistar rats. Asian Pacific Journal of Tropical Medicine 2(4): 6–10.
• Tandon, P., Abrol, Y.P. & Kumaria, S. (Editors), 2007. Biodiversity and its significance. I.K. International, New Delhi, India. 370 pp.
• Watt, J.M. & Breyer-Brandwijk, M.G., 1962. The medicinal and poisonous plants of southern and eastern Africa. 2nd Edition. E. and S. Livingstone, London, United Kingdom. 1457 pp.

Sources of illustration

Author(s)

•	E. Wabuyele East African Herbarium, National Museums of Kenya, P.O. Box 45166, 00100 Nairobi, Kenya

Based on PROSEA 17: ‘Fibre plants’.

Editors

•	M. Brink PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands
•	E.G. Achigan Dako PROTA Network Office Africa, World Agroforestry Centre (ICRAF), P.O. Box 30677-00100, Nairobi, Kenya

Photo editor

•	G.H. Schmelzer PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands

Correct citation of this article

Wabuyele, E., 2011. Abroma augusta (L.) L.f. [Internet] Record from PROTA4U. Brink, M. & Achigan-Dako, E.G. (Editors). PROTA (Plant Resources of Tropical Africa / Ressources végétales de l’Afrique tropicale), Wageningen, Netherlands. <http://www.prota4u.org/search.asp>. Accessed .

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