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Para Rubber Tree

Hevea brasiliensis (Willd. ex A. Juss.) Müll. Arg.

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This species is cultivated in great numbers for the production of rubber.
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Missouri Botanical Garden, 4344 Shaw Boulevard, St. Louis, MO, 63110 USA
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Flora of China Vol. 11: 265 in eFloras.org, Missouri Botanical Garden. Accessed Nov 12, 2008.
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Wu Zhengyi, Peter H. Raven & Hong Deyuan
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Description

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Large trees, up to 30 m tall, with much milky juice. Petiole 5-15 cm, apex usually with 2(-4) glands; leaflets 3, elliptic, 10-25 × 4-10 cm, both surfaces glabrous, base cuneate, margin entire, apex acute to acuminate; lateral veins 10-16, reticulate veins prominent. Panicles axillary, to 16 cm, gray-white pubescent. Male flowers: sepals ovate-lanceolate, ca. 2 mm; stamens 10, in 2 series; anthers 2-locular, longitudinally dehiscent. Female flowers: sepals as in male, but larger; ovary (2 or)3(-6)-locular; stigmas 3, sessile. Capsules ellipsoidal, 5-6 cm in diam., with 3 longitudinal grooves, apex rostrate, base retuse; epicarp thinner, with reticulate stripes; endocarp thicker, woody. Seeds ellipsoidal, gray-brownish, maculate-striate. Fl. May-Jun, fr. Aug-Sep.
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Missouri Botanical Garden, 4344 Shaw Boulevard, St. Louis, MO, 63110 USA
bibliographic citation
Flora of China Vol. 11: 265 in eFloras.org, Missouri Botanical Garden. Accessed Nov 12, 2008.
source
Flora of China @ eFloras.org
editor
Wu Zhengyi, Peter H. Raven & Hong Deyuan
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eFloras.org
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Habitat & Distribution

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Cultivated. S Fujian, Guangdong, Guangxi, Hainan, Taiwan, Yunnan [native to Brazil; widely introduced throughout the tropics].
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Missouri Botanical Garden, 4344 Shaw Boulevard, St. Louis, MO, 63110 USA
bibliographic citation
Flora of China Vol. 11: 265 in eFloras.org, Missouri Botanical Garden. Accessed Nov 12, 2008.
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Flora of China @ eFloras.org
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Wu Zhengyi, Peter H. Raven & Hong Deyuan
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eFloras.org
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Synonym

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Siphonia brasiliensis Willdenow ex A. Jussieu, Euphorb. Gen. t. 12. 1824.
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Missouri Botanical Garden, 4344 Shaw Boulevard, St. Louis, MO, 63110 USA
bibliographic citation
Flora of China Vol. 11: 265 in eFloras.org, Missouri Botanical Garden. Accessed Nov 12, 2008.
source
Flora of China @ eFloras.org
editor
Wu Zhengyi, Peter H. Raven & Hong Deyuan
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eFloras.org
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Brief Summary

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Hevea brasiliensis, the rubber tree or Pará rubber tree, is a medium to large tropical tree in the Euphorbiaceae (spurge family) native to South America (the Brazilian and Bolivian region covering Amazon and Orinoco river basins), which produces a milky sap (latex) that is the primary source of natural rubber. Although some wild-grown trees are still tapped for their sap, most commercial production now comes from rubber tree plantations in southern and southeastern Asia (including Indonesia, Malaysia, and Sri Lanka), as well as western Africa. Other species that contain latex that may be used for natural rubber production include gutta-percha (Palaquium gutta), rubber fig (Ficus elastica), and Panama rubber tree (Castilla elastica), although none are used to the same extent as H. brasiliensis. The rubber tree may grow to 30 m (100 ft) or more where it occurs in the wild, although plantation trees generally reach heights of around 17 m (60 ft). The thick, leathery leaves, up to 60 cm (24 in) long, are compound, with 3 elliptic leaflets, each with entire (unserrated) margins and prominent secondary veins. The inflorescence is a many-flowered panicle (a much-branched cluster), up to 16 cm (6.5 in) long, with a small white petal-less female flower in the center, surrounded by small 5-lobed or dissected male flowers. The fruit is a large ellipsoidal capsule, usually 3-valved and 5 to 6 cm in diameter (2 to 2.5 in), containing gray-brown, flattened ellipsoidal seeds. The sap, which can be harvested from the inner bark when the tree reaches 6 or 7 years, is obtained by tapping—cutting the bark and letting the sap drip out, then coagulated. Amazonian natives had long used the rubber that naturally forms from the latex, including to make balls used in early games, but the untreated rubber would become soft and sticky in the heat, and brittle in the cold. This problem was remedied by the chemical process known as vulcanization, developed by Charles Goodyear in the 1840s, which allows rubber to remain firm but flexible in all temperatures. Vulcanization allowed natural rubber products to become commercially successful, and promoted commercial plantations in tropical areas in Asia and Africa. In 2010, 11 countries accounted for 92% of global production of natural rubber from H. brasiliensis: Cambodia; China; India, Indonesia; Malaysia; Papua New Guinea; Philippines; Singapore; Sri Lanka; Thailand; and Vietnam. Natural rubber is not produced in significant amounts in its native South America, because trees there are widely affected by South American leaf blight, caused by the fungus Microcyclus ulei (Ascomycota). Synthetic rubber, which is processed from petroleum and was developed during the 1920s through 1940s, now makes up roughly 70% of the rubber manufactured worldwide, but natural rubber continues to have important uses in manufacturing and textiles. (ANRPC 2012, Bailey et al. 1976, Encyclopedia Britannica 1993, Flora of China 2008, Wikipedia 2012.)
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Jacqueline Courteau
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Economic Significance

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This tree is extremely valuable to humans, it is the source of latex and natural rubber and is the most economically important crop of the genus Hevea. It is grown on monoculture crop plantations mostly in South America and some parts of Africa.

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Amy Chang
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Amy Chang
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Hevea brasiliensis

provided by wikipedia EN

Hevea brasiliensis, the Pará rubber tree, sharinga tree, seringueira, or most commonly, rubber tree or rubber plant, is a flowering plant belonging to the spurge family Euphorbiaceae originally native to the Amazon basin, but is now pantropical in distribution due to introductions. It is the most economically important member of the genus Hevea because the milky latex extracted from the tree is the primary source of natural rubber.

Description

Canopy and trunk, Thailand

H. brasiliensis is a tall deciduous tree growing to a height of up to 43 m (141 ft) in the wild. Cultivated trees are usually much smaller because drawing off the latex restricts their growth. The trunk is cylindrical and may have a swollen, bottle-shaped base. The bark is some shade of brown, and the inner bark oozes latex when damaged. The leaves have three leaflets and are spirally arranged. The inflorescence include separate male and female flowers. The flowers are pungent, creamy-yellow and have no petals. The fruit is a capsule that contains three large seeds; it opens explosively when ripe.[2]

Rubber tree plantation

Seeds
A sprouting seed in a house backyard in Malaysia

In the wild, the tree can reach a height of up to 140 feet (43 m). The white or yellow latex occurs in latex vessels in the bark, mostly outside the phloem. These vessels spiral up the tree in a right-handed helix which forms an angle of about 30 degrees with the horizontal, and can grow as high as 45 feet (14 m).[3]

In plantations, the trees are generally smaller for two reasons: 1) trees grow more slowly when they are tapped for latex, and 2) trees are generally cut down after only 30 years, because latex production declines as trees age, and they are no longer economically productive. The tree requires a tropical or subtropical climate with a minimum of about 1,200 mm (50 in) per year of rainfall, and no frost.[4] If frost does occur, the results can be disastrous for production. One frost can cause the rubber from an entire plantation to become brittle and break once it has been refined.[5]

Latex tapping

Trunk crosssection
Latex being collected from an incised rubber tree and a bucket of collected latex

The natural rubber tree takes between seven and ten years to deliver the first harvest. [6] Harvesters make incisions across the latex vessels, just deep enough to tap the vessels without harming the tree's growth, and the latex is collected in small buckets. This process is known as rubber tapping. Latex production is highly variable from tree to tree and across clone types.[3]

Wood harvesting

As latex production declines with age, rubber trees are generally felled when they reach the age of 25 to 30 years. The earlier practice was to burn the trees, but in recent decades, the wood has been harvested for furniture making.[3]

History

The South American rubber tree grew only in the Amazon rainforest, and increasing demand and the discovery of the vulcanization procedure in 1839 led to the rubber boom in that region, enriching the cities of Belém, Santarém, and Manaus in Brazil and Iquitos, Peru, from 1840 to 1913. In Brazil, before the name was changed to 'Seringueira' the initial name of the plant was 'pará rubber tree', derived from the name of the province of Grão-Pará. In Peru, the tree was called 'árbol del caucho', and the latex extracted from it was called 'caucho'. The tree was used to obtain rubber by the natives who inhabited its geographical distribution. The Olmec people of Mesoamerica extracted and produced similar forms of primitive rubber from analogous latex-producing trees such as Castilla elastica as early as 3,600 years ago. The rubber was used, among other things, to make the balls used in the Mesoamerican ballgame.[7] Early attempts were made in 1873 to grow H. brasilensis outside Brazil. After some effort, 12 seedlings were germinated at the Royal Botanic Gardens, Kew. These were sent to India for cultivation, but died. A second attempt was then made, some 70,000 seeds being smuggled to Kew in 1875, by Henry Wickham, in the service of the British Empire.[8]: 55 [9][10] About four percent of these germinated, and in 1876, about 2,000 seedlings were sent, in Wardian cases, to Ceylon (modern day Sri Lanka) and 22 were sent to the botanic gardens in Singapore.

Once established outside its native country, rubber was extensively propagated in the British colonies. Rubber trees were brought to the botanical gardens at Buitenzorg, Java, in 1883.[11] By 1898, a rubber plantation had been established in Malaya, with imported Chinese field workers being the dominant work force in rubber production in the early 20th-century.[12]

The cultivation of the tree in South America (Amazon) ended early in the 20th century because of indigenous blights that targeted the rubber tree.[4] The blight, called South American leaf blight, is caused by the ascomycete Pseudocercospora ulei,[13][14][15] also called Microcyclus ulei,[16] or Dothidella ulei. Rubber production then moved to parts of the world where it is not indigenous, and therefore not affected by local plant diseases.[17] Today, most rubber tree plantations are in South and Southeast Asia, the top rubber producing countries in 2011 being Thailand, Indonesia, Malaysia, India and Vietnam.[18]

Environmental concerns

The toxicity of arsenic to insects, bacteria, and fungi has led to the heavy use of arsenic trioxide on rubber plantations, especially in Malaysia.[19]

The majority of the rubber trees in Southeast Asia are clones of varieties highly susceptible to the South American leaf blight—Pseudocercospora ulei. For these reasons, environmental historian Charles C. Mann, in his 2011 book, 1493: Uncovering the New World Columbus Created, predicted that the Southeast Asian rubber plantations will be ravaged by the blight in the not-too-distant future, thus creating a potential calamity for international industry.[20]

Secondary metabolites

H. brasiliensis produces cyanogenic glycosides (CGs) as a defense, concentrated in the seeds. (Although effective against other attackers, CGs are not very effective against fungal pathogens. In rare cases, they are even detrimental. This is the case for H. b., which actually suffers worse from Pseudocercospora ulei if the rubber tree produces more CGs. This may be because cyanide inhibits the production of other defensive metabolites. This results in significantly divergent subpopulations with selection for or against CGs, depending on local likelihoods of fungal or non-fungal pest pressure.) The carbon and nitrogen in CGs are recycled for growth and latex production if needed, and the ease of doing so makes them an attractive nitrogen store - especially if the plant is light-deprived and storage in photosynthesis proteins would thus be unhelpful. The α-hydroxynitrilases are likely contained in the cytoplasm. Linamarin is hydrolyzed by an accompanying linamarase, a β-glycosidase. H. b. linamarase does act upon linamarin because it is a monoglucoside, while it does not for linustatin because it is a diglucoside - in fact, the production of linustatin inhibits linamarase cleavage of linamarin. This allows intra-plant, post-synthesis transport of linustatin without risking premature cleavage.[21]

See also

Notes

  1. ^ Fabriani, F. & Hills, R. 2020. Hevea brasiliensis. The IUCN Red List of Threatened Species 2020: e.T62003521A62003529. https://dx.doi.org/10.2305/IUCN.UK.2020-2.RLTS.T62003521A62003529.en. Accessed on 28 October 2022.
  2. ^ "Hevea brasiliensis (Willd. ex A.Juss.) Müll.Arg". Plants of the World online. Kew Science. Retrieved 31 March 2017.
  3. ^ a b c "Rubber tapping". UN FAO. Retrieved 29 May 2017.
  4. ^ a b "Elastomer-The rubber tree", Encyclopædia Britannica, 2008
  5. ^ "The rubber tree". UN FAO. Retrieved 29 May 2017.
  6. ^ "Natural rubber from dandelions".
  7. ^ Langenheim, J.H. (13 January 2010). "Introduction to Rubber Usage among the Maya". Maya Archaeology. Retrieved 29 May 2017.
  8. ^ "The Brazilian Armed Forces: Current changes, new challenges", Dreifuss, R. Armand. In JOHN OLSLICK ELDER STREET THIEF KKALAJOA554977 ternational Seminar Research Committee Armed Forces and Society, Romania, 2002. Retrieved August 19, 2009 from "Archived copy" (PDF). Archived from the original (PDF) on 2009-07-31. Retrieved 2009-08-19.{{cite web}}: CS1 maint: archived copy as title (link)
  9. ^ "Amazon - The Animation", Greepeace Digital. Artificial Environments, n/d. Retrieved August 19, 2009 from "The Animation". Archived from the original on 2011-07-07. Retrieved 2009-08-19.
  10. ^ "Acre: História e etnologia", Marco António Gonçalves (Org.). Núcleo de Etnologia Indígena Laboratório de Pesquisa Social/IFCS - UFRJ, n/d. Retrieved August 19, 2009 from http://eduardoeginacarli.blogspot.com/2007_07_01_archive.html
  11. ^ Winchester, Simon (2003). Krakatoa: The Day the World Exploded, August 27, 1883. HarperCollins. pp. 223–224. ISBN 0-06-621285-5.
  12. ^ Harold A. Crouch, Economic Change, Social Structure, and the Political System in Southeast Asia, Institute of Southeast Asian Studies: Singapore 1985, pp. 16–17 ISBN 9971-988-23-2
  13. ^ Guyot, Jean; Le Guen, Vincent (2018). "A Review of a Century of Studies on South American Leaf Blight of the Rubber Tree". Plant Disease. American Phytopathological Society. 102 (6): 1052–1065. doi:10.1094/pdis-04-17-0592-fe. ISSN 0191-2917. PMID 30673445.
  14. ^ "Pseudocercospora ulei (MICCUL)[Overview]". Global Database. EPPO (European and Mediterranean Plant Protection Organization). 2002-04-09. Retrieved 2021-08-28.
  15. ^ Erasing the Past: A New Identity for the Damoclean Pathogen Causing South American Leaf Blight of Rubber
  16. ^ South American Leaf Blight of rubber (Microcyclus ulei), plantwise.org
  17. ^ Prance, Ghillean (2005). Prance, Ghillean; Nesbitt, Mark (eds.). The Cultural History of Plants. Routledge. p. 28. ISBN 0415927463.
  18. ^ "The Top 5 Rubber Producing Countries". Top 5 of Anything. Retrieved 29 May 2017.
  19. ^ Sabina C. Grund, Kunibert Hanusch, Hans Uwe Wolf. "Arsenic and Arsenic Compounds". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a03_113.pub2.{{cite encyclopedia}}: CS1 maint: multiple names: authors list (link)
  20. ^ Mann, Charles C. (2011). 1493: Uncovering the New World Columbus Created. New York: Knopf. ISBN 978-0-307-26572-2.
  21. ^ Gleadow, Roslyn M.; Møller, Birger Lindberg (2014-04-29). "Cyanogenic Glycosides: Synthesis, Physiology, and Phenotypic Plasticity". Annual Review of Plant Biology. Annual Reviews. 65 (1): 155–185. doi:10.1146/annurev-arplant-050213-040027. ISSN 1543-5008. PMID 24579992. S2CID 207575721.

References

  • Zhang, J., Huss, V.A.R., Sun, X., Chang, K. and Pan, D. 2008. Morphology and phylogenetic position of a trebouxiophycean green algae (Chlorophyta) growing on the rubber tree, Hevea brasiliensis, with the description of a new genus and species. Eur. J. Phycol. 43(2): 185–193.
  • Charles C. Mann 2011. 1493. Uncovering the New World Columbus Created. Ch.7 Black Gold.

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Hevea brasiliensis: Brief Summary

provided by wikipedia EN

Hevea brasiliensis, the Pará rubber tree, sharinga tree, seringueira, or most commonly, rubber tree or rubber plant, is a flowering plant belonging to the spurge family Euphorbiaceae originally native to the Amazon basin, but is now pantropical in distribution due to introductions. It is the most economically important member of the genus Hevea because the milky latex extracted from the tree is the primary source of natural rubber.

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