Overview

Brief Summary

Palaquium is a genus of trees in the family Sapotaceae that includes around 110 species with representatives occurring from Taiwan and Indomalesia (i.e., India to New Guinea) to Samoa. The genus is best known as the source of gutta-percha, a product obtained from the latex of the tree (mainly P. gutta of Sumatra, Malaya, Java, and Borneo) after tapping or cutting it down. This rubbery substance, which softens when heated, had many uses historically (including as an insulator for the first trans-Atlantic telephone cables and in the manufacture of golf balls) and is still used in dentistry. After early destructive tapping, some plantations were established in Java and Singapore. (Heywood 1993; Mabberley 2008)

Like rubber, gutta-percha is composed mainly of a polymer of isoprene, but it differs from rubber in having trans- rather than cis- isomerization, in that it is almost non-elastic, in that it is a better insulator of heat and electricity, and in that it becomes plastic when heated and upon cooling retains the shape acquired when it was heated (Heywood 1993).

Gutta-percha has a rich history (Brown 2003)  but its only common use today is in dentistry (Tronstad 2009) and there are active efforts by dental researchers to replace its with other materials (e.g., Baba et al. 2010).

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Distribution

The genus Palaquium includes around 110 species, with representatives occurring from Taiwan and Indomalesia (i.e., India to New Guinea) to Samoa (Mabberley 2008).

  • Mabberley, D.J. 2008. Mabberley's Plant-book, 3rd edition. Cambridge University Press, Cambridge, UK.
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Molecular Biology and Genetics

Molecular Biology

Statistics of barcoding coverage

Barcode of Life Data Systems (BOLD) Stats
Specimen Records:34
Specimens with Sequences:45
Specimens with Barcodes:44
Species:15
Species With Barcodes:14
Public Records:11
Public Species:4
Public BINs:0
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Wikipedia

Palaquium

Palaquium is a genus of about 120 species of trees in the Sapotaceae family.[4] Their range is from India across Southeast Asia, Malesia, Papuasia and Australasia, to the western Pacific Islands.[3][5]

Description[edit]

Within their range, Palaquium species are mostly found in the Philippines and Borneo. In Borneo many species are recorded in the Malaysian states of Sabah and Sarawak.[5]

The leaves are typically spirally arranged and often clustered near twig ends. Flowers are mostly bisexual, though some unisexual instances are known. Fruits are one or two-seeded with rare instances of several seeds. Palaquium habitats are coastal, lowland mixed dipterocarp, swamp and montane forests.[5]

Some species, for example Palaquium gutta, are well known for producing gutta-percha latex.[5]

Species[edit]

As of November 2013 The Plant List recognises 120 accepted species:[6]

  1. Palaquium abundantiflorum H.J.Lam
  2. Palaquium amboinense Burck
  3. Palaquium annamense Lecomte
  4. Palaquium barnesii Merr.
  5. Palaquium bataanense Merr.
  6. Palaquium beccarianum (Pierre) P.Royen
  7. Palaquium bourdillonii Brandis
  8. Palaquium brassii H.J.Lam
  9. Palaquium burckii H.J.Lam
  10. Palaquium calophyllum (Teijsm. & Binn.) Pierre ex Burck
  11. Palaquium canaliculatum (Thwaites) Engl.
  12. Palaquium clarkeanum King & Gamble
  13. Palaquium cochleariifolium P.Royen
  14. Palaquium confertum H.J.Lam
  15. Palaquium crassifolium Pierre ex Dubard
  16. Palaquium cryptocariifolium P.Royen
  17. Palaquium cuprifolium Elmer
  18. Palaquium dasyphyllum Pierre ex Dubard
  19. Palaquium decurrens H.J.Lam
  20. Palaquium densivenium K.Krause
  21. Palaquium dubardii Elmer
  22. Palaquium edenii Pierre ex Dubard
  23. Palaquium elegans Griffoen & H.J.Lam
  24. Palaquium ellipticum (Dalzell) Baill.
  25. Palaquium elliptilimbum Merr.
  26. Palaquium elongatum Merr.
  27. Palaquium eriocalyx H.J.Lam
  28. Palaquium erythrospermum H.J.Lam
  29. Palaquium ferrugineum Pierre ex Dubard
  30. Palaquium fidjiense Pierre ex Dubard
  31. Palaquium firmum C.T.White
  32. Palaquium formosanum Hayata
  33. Palaquium foxworthyi Merr.
  34. Palaquium galactoxylum (F.Muell.) H.J.Lam
  35. Palaquium garrettii Fletcher
  36. Palaquium gigantifolium Merr.
  37. Palaquium glabrifolium Merr.
  38. Palaquium glabrum Merr.
  39. Palaquium globosum H.J.Lam
  40. Palaquium grande (Thwaites) Engl.
  41. Palaquium gutta (Hook.) Burck
  42. Palaquium hansenii Chantaranothai
  43. Palaquium herveyi King & Gamble
  44. Palaquium heterosepalum Merr.
  45. Palaquium hexandrum (Griff.) Baill.
  46. Palaquium hinmolpedda P.Royen
  47. Palaquium hispidum H.J.Lam
  48. Palaquium hornei (Hartog ex Baker) Dubard
  49. Palaquium impressionervium Ng
  50. Palaquium karrak Kaneh.
  51. Palaquium kinabaluense P.Royen
  52. Palaquium laevifolium (Thwaites) Engl.
  53. Palaquium lanceolatum Blanco
  54. Palaquium leiocarpum Boerl.
  55. Palaquium lisophyllum Pierre ex Dubard
  56. Palaquium lobbianum Burck
  57. Palaquium loheri Merr.
  58. Palaquium luzoniense (Fern.-Vill.) Vidal
  59. Palaquium macrocarpum Burck
  60. Palaquium maingayi (C.B.Clarke) Engl.
  61. Palaquium majas H.J.Lam
  62. Palaquium maliliense P.Royen
  63. Palaquium masuui P.Royen
  64. Palaquium merrillii Dubard
  65. Palaquium microphyllum King & Gamble
  66. Palaquium mindanaense Merr.
  67. Palaquium montanum Elmer
  68. Palaquium morobense P.Royen
  69. Palaquium multiflorum Pierre ex Dubard
  70. Palaquium neoebudicum Guillaumin
  71. Palaquium njatoh Burck
  72. Palaquium obovatum (Griff.) Engl.
  73. Palaquium obtusifolium Burck
  74. Palaquium oleosum Burck
  75. Palaquium ottolanderi Koord. & Valeton
  76. Palaquium oxleyanum Pierre
  77. Palaquium oxyspermum H.J.Lam
  78. Palaquium pauciflorum (Thwaites) Engl.
  79. Palaquium petiolare (Thwaites) Engl.
  80. Palaquium philippense (Perr.) C.B.Rob.
  81. Palaquium pierrei Burck
  82. Palaquium pinnatinervium Elmer
  83. Palaquium polyandrum C.B.Rob.
  84. Palaquium polyanthum (Wall. ex G.Don) Baill.
  85. Palaquium porphyreum A.C.Sm. & S.P.Darwin
  86. Palaquium pseudocalophyllum H.J.Lam
  87. Palaquium pseudocuneatum H.J.Lam
  88. Palaquium pseudorostratum H.J.Lam
  89. Palaquium quercifolium (de Vriese) Burck
  90. Palaquium ravii Sasidh. & Vink
  91. Palaquium regina-montium Ng
  92. Palaquium ridleyi King & Gamble
  93. Palaquium rigidum Pierre ex Dubard
  94. Palaquium rioense H.J.Lam
  95. Palaquium rivulare H.J.Lam
  96. Palaquium rostratum (Miq.) Burck
  97. Palaquium rubiginosum (Thwaites) Engl.
  98. Palaquium rufolanigerum P.Royen
  99. Palaquium sambasense Pierre ex Dubard
  100. Palaquium semaram H.J.Lam
  101. Palaquium sericeum H.J.Lam
  102. Palaquium simun P.Royen
  103. Palaquium sorsogonense Elmer ex H.J.Lam
  104. Palaquium stehlinii Christoph.
  105. Palaquium stellatum King & Gamble
  106. Palaquium stipulare Pierre ex Dubard
  107. Palaquium sukoei C.E.C.Fisch.
  108. Palaquium sumatranum Burck
  109. Palaquium supfianum Schltr.
  110. Palaquium tenuifolium K.Krause
  111. Palaquium tenuipetiolatum Merr.
  112. Palaquium thwaitesii Trimen
  113. Palaquium tjipetirense H.J.Lam
  114. Palaquium vexillatum P.Royen
  115. Palaquium vidalii Pierre ex Dubard
  116. Palaquium vitilevuense Gilly ex Royen
  117. Palaquium walsurifolium Pierre ex Dubard
  118. Palaquium warburgianum Schltr. ex K.Krause
  119. Palaquium xanthochymum (de Vriese) Pierre ex Burck
  120. Palaquium zeylanicum Verdc.

References[edit]

  1. ^ 1897 illustration from Franz Eugen Köhler, Köhler's Medizinal-Pflanzen, as Palaquium oblongifolium, synonym of P. gutta
  2. ^ "World Checklist of Selected Plant Families". Royal Botanic Gardens, Kew. Retrieved 5 December 2013.  |chapter= ignored (help)
  3. ^ a b Kew World Checklist of Selcted Plant Families
  4. ^ Stevens, Peter F. (2001). "Angiosperm Phylogeny Website". Version 13, 2013 with updates. Retrieved 6 December 2013.  |chapter= ignored (help)
  5. ^ a b c d Mohtar, A.P. Abang Mohd. (April 2002). "Palaquium Blanco". In Soepadmo, E.; Saw, L. G.; Chung, R. C. K. Tree Flora of Sabah and Sarawak. (free online from the publisher, lesser resolution scan PDF versions) 4. Forest Research Institute Malaysia. pp. 271–312. ISBN 983-2181-27-5. Retrieved 5 December 2013. 
  6. ^ "Palaquium". The Plant List. Retrieved 5 December 2013. 


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Gutta-percha

Gutta-percha is a name for a set of trees, mostly of the genus Palaquium, noted for their latex. The same term is used to refer to the rigid natural latex itself that is produced from the sap of these trees, particularly from the species Palaquium gutta.

Palaquium gutta

Heavy use of gutta-percha during the second half of the nineteenth century, particularly as insulation for underwater telegraph cables, led to unsustainable harvesting and a collapse of the supply.[1]

The word 'gutta-percha' comes from the plant's name in Malay, getah perca, which translates as "percha sap".

Taxonomy[edit]

The trees are 5–30 metres tall and up to 1 metre in trunk diameter. The leaves are evergreen, alternate or spirally arranged, simple, entire, 8–25 cm long, and glossy green above, often yellow or glaucous below. The flowers are produced in small clusters along the stems, each flower with a white corolla with 4–7 (mostly 6) acute lobes. The fruit is an ovoid 3–7 cm berry, containing 1–4 seeds; in many species the fruit is edible.

In Australia, gutta-percha is a common name specifically used for the tree Excoecaria parvifolia, which yields an aromatic, heavy, dark brown timber. It is also called "northern birch". This particular species is not related to the Palaquium genus.

Gutta-percha tree

Chemistry[edit]

Chemically, gutta-percha is a polyterpene, a polymer of isoprene, or polyisoprene, specifically (trans-1,4-polyisoprene). The cis structure of polyisoprene is the common latex elastomer. While latex rubbers are amorphous in molecular structure, gutta-percha (the trans structure) crystallizes, leading to a more rigid material.

Chemical structure of gutta-percha

Uses[edit]

Electronics[edit]

Gutta-percha latex is biologically inert, resilient, and is a good electrical insulator with a high dielectric strength. The wood of many species is also valuable.

Western inventors discovered the properties of gutta-percha latex in 1842, although the local population in its Malayan habitat had used it for a variety of applications for centuries. Allowing this fluid to evaporate and coagulate in the sun produced a latex which could be made flexible again with hot water, but which did not become brittle, unlike rubber prior to the discovery of vulcanization.

By 1845, telegraph wires insulated with gutta-percha were being manufactured in the United Kingdom. It served as the insulating material for some of the earliest undersea telegraph cables, including the first transatlantic telegraph cable. Gutta-percha was particularly suitable for this purpose, as it was not attacked by marine plants or animals, a problem which had disabled previous undersea cables. The material was a major constituent of Chatterton's compound used as an insulating sealant for telegraph and other electrical cables. Polyethylene's superior insulative property has displaced it.

Dentistry[edit]

The same bioinertness that made it suitable for marine cables also means it does not readily react within the human body. It is consequently used in a variety of surgical devices and for dental applications during root canal therapy. It is the predominant material used to obturate, or fill the empty space inside the root of a tooth after it has undergone endodontic therapy. Its physical and chemical properties, including but not limited to its inertness and biocompatibility, melting point, ductility and malleability, afford it an important role in the field of endodontics.

Other[edit]

In the mid-19th century, gutta-percha was also used to make furniture, notably by the Gutta-Percha Company (established in 1847). Several of these highly ornate, revival-style pieces were shown at the 1851 Great Exhibition in Hyde Park, London. Molded furniture forms, emulating carved wood, were attacked by proponents of the design reform movement, who advocated truth to materials. It was also used to make "mourning" jewelry, because it was dark in color and could be easily molded into beads or other shapes. Pistol hand grips and rifle shoulder pads were also made from gutta-percha, since it was hard and durable, though it fell into disuse when plastics such as Bakelite became available. Gutta-percha found use in canes and walking sticks as well; in 1856, Representative Preston Brooks used a cane made of gutta-percha as a weapon in his infamous attack on Senator Charles Sumner.

The material was quickly adopted for numerous other applications. The "guttie" golf ball (which had a solid gutta-percha core) revolutionized the game. Gutta-percha remained an industrial staple well into the 20th century, when it was gradually replaced with superior (generally synthetic) materials, though a similar and cheaper natural material called balatá is often used in gutta-percha's place. The two materials are almost identical, and balatá is often called gutta-balatá.

Cultural references[edit]

Gutta-percha was featured in the pilot movie for the original 1968 Hawaii Five-O television series, Cocoon. The primary antagonist, Wo Fat, used gutta-percha to seal the eyes, nose and mouth of victims during interrogations.

In an episode of The Wild Wild West, 0406 Titled: "The Night of the Kraken" gutta-percha was used to create a mechanical sea monster.

The Russian author Dmitry Grigorovich's 1883 story "The Gutta-Percha Boy" ("Guttaperchevyi mal'chik") is about a poor eight-year-old orphan, Petya, who becomes a circus performer. He is nicknamed the Gutta-Percha boy because of his extraordinary flexible joints, and plunges to his death during a performance in front of children from a well-to-do family. Two film versions have been made of the story in Russia (in 1915 and 1957), and the soubriquet "Gutta-Percha boy," referring to someone who is unusually bendy, gained currency in Russia well beyond the fame of the author.

In the novel Five Weeks in a Balloon by Jules Verne, the balloon is coated with gutta-percha.

See also[edit]

References[edit]

  1. ^ Tully, John (2009). "A Victorian Ecological Disaster: Imperialism, the Telegraph, and Gutta-Percha". Journal of World History 20 (4): 559–579. 
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