Taxus cuspidata

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Taxus cuspidata
Taxus cuspidata fruits.JPG
Scientific classification e
Kingdom: Plantae
Division: Pinophyta
Class: Pinopsida
Order: Pinales
Family: Taxaceae
Genus: Taxus
Species: T. cuspidata
Binomial name
Taxus cuspidata
Siebold & Zucc.

Taxus cuspidata, the Japanese yew[2] or spreading yew, is a member of the genus Taxus, native to Japan, Korea, northeast China and the extreme southeast of Russia.

It is an evergreen tree or large shrub growing to 10–18 m tall, with a trunk up to 60 cm diameter. The leaves are lanceolate, flat, dark green, 1–3 cm long and 2–3 mm broad, arranged spirally on the stem, but with the leaf bases twisted to align the leaves in two flattish rows either side of the stem except on erect leading shoots where the spiral arrangement is more obvious.

The seed cones are highly modified, each cone containing a single seed 4–8 mm long partly surrounded by a modified scale which develops into a soft, bright red berry-like structure called an aril, 8–12 mm long and wide and open at the end. The arils are mature 6–9 months after pollination. Individual trees from Sikhote-Alin are known to have been 1,000 years old.[3]

Uses[edit]

It is widely grown in eastern Asia and eastern North America as an ornamental plant.

Toxicity[edit]

The entire yew bush, except for the fleshy berry surrounding the seed, is toxic due to a group of chemicals called taxine alkaloids.[4] Yew poisonings are relatively common in both domestic and wild animals who consume the plant accidentally.[5][6][7] Taxine B, the most toxic of the taxine alkaloids, is a cardiotoxin which works by disrupting the calcium and sodium currents of the myocardial cells.[8][9] The taxine alkaloids are absorbed quickly from the intestine and in high enough quantities can cause death due to cardiac arrest or respiratory failure.[10] Ingesting yew causes symptoms such as dizziness, dilation of pupils, abdominal pain, nausea and an irregular heartbeat.[11]

The minimum lethal dose (LDmin) of yew leaves is 3.0-6.5 mg/kg body weight for humans, 1–2 mg/kg for horses and 82.5 mg/kg for chickens.[12] There is currently no known antidotes for yew poisoning but drugs such as atropine have been used to treat the symptoms.[13]

References[edit]

  1. ^ Conifer Specialist Group (1998). "Taxus cuspidata". IUCN Red List of Threatened Species. Version 2006. International Union for Conservation of Nature. Retrieved 5 May 2006. 
  2. ^ "Taxus cuspidata". Natural Resources Conservation Service PLANTS Database. USDA. Retrieved 8 December 2015. 
  3. ^ "Памятник природы "Сихотэ - Алинь". Центр реабилитации диких животных "УТЕС"" [The nature monument "Sikhote - Alin". Center for the rehabilitation of wild animals "UTES"]. Туристические комплексы[Tourist complexes] (in Russian). Archived from the original on 2007-09-29. 
  4. ^ Wilson, Christina R.; Sauer, John-Michael; Hooser, Stephen B. (2001). "Taxines: a review of the mechanism and toxicity of yew (Taxus spp.) alkaloids". Toxicon. 39 (2-3): 175–185. doi:10.1016/s0041-0101(00)00146-x. ISSN 0041-0101. 
  5. ^ "JAPANESE YEW PLANT POISONING - USA: (IDAHO) PRONGHORN ANTELOPE". ProMED-mail. 24 January 2016. Retrieved 25 January 2016. 
  6. ^ "PLANT POISONING, CERVID - USA: (ALASKA) ORNAMENTAL TREE, MOOSE". ProMED-mail. 22 February 2011. Retrieved 25 January 2016. 
  7. ^ Tiwary, Asheesh K.; Puschner, Birgit; Kinde, Hailu; Tor, Elizabeth R. (May 2005). "Diagnosis of Taxus (yew) poisoning in a horse". Journal of Veterinary Diagnostic Investigation: Official Publication of the American Association of Veterinary Laboratory Diagnosticians, Inc. 17 (3): 252–255. doi:10.1177/104063870501700307. ISSN 1040-6387. PMID 15945382. 
  8. ^ Garland, Tam; Barr, A. Catherine (1998). Toxic plants and other natural toxicants. International Symposium on Poisonous Plants (5th : 1997 : Texas). Wallingford, England: CAB International. ISBN 0851992633. OCLC 39013798. 
  9. ^ Alloatti, G.; Penna, C.; Levi, R. C.; Gallo, M. P.; Appendino, G.; Fenoglio, I. (1996). "Effects of yew alkaloids and related compounds on guinea-pig isolated perfused heart and papillary muscle". Life Sciences. 58 (10): 845–854. ISSN 0024-3205. PMID 8602118. 
  10. ^ Fuller, Thomas C.; McClintock, Elizabeth May (1986). Poisonous plants of California. Berkeley: University of California Press. ISBN 0520055683. OCLC 13009854. 
  11. ^ Turner, Nancy J.; von Aderkas, P.; Turner, Nancy J. (2009). The North American guide to common poisonous plants and mushrooms. Portland: Timber Press. ISBN 9781604691450. OCLC 747112294. 
  12. ^ Gupta, Ramesh C. (2012). Veterinary toxicology : basic and clinical principles (2nd ed.). Oxford: Academic. ISBN 9780123859266. OCLC 778786624. 
  13. ^ Wilson, Christina R.; Hooser, Stephen B. (2018). Veterinary Toxicology. Elsevier. pp. 947–954. doi:10.1016/b978-0-12-811410-0.00066-0. ISBN 9780128114100.