Biology:Magnoliids

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Magnoliids, Magnoliidae or Magnolianae are a clade of flowering plants. With more than 10,000 species, including magnolias, nutmeg, bay laurel, cinnamon, avocado, black pepper, tulip tree and many others, it is the third-largest group of angiosperms after the eudicots and monocots.[1] The group is characterized by trimerous flowers, pollen with one pore, and usually branching-veined leaves.

Some members of the subclass are among the earliest angiosperms and share anatomical similarities with gymnosperms like stamens that resemble the male cone scales of conifers and carpels found on the long flowering axis.[2] According to molecular clock calculations, the lineage that led to magnoliids split from other plants about 135 million years ago[3] or 160-165 million years ago.[4]

Classification

"Magnoliidae" is the botanical name of a subclass, and "magnoliids" is an informal name that does not conform to the International Code of Nomenclature for algae, fungi, and plants. The circumscription of a subclass will vary with the taxonomic system being used. The only requirement is that it must include the family Magnoliaceae.[5] The informal name "magnoliids" is used by some researchers to avoid the confusion that recently surrounds the name "Magnoliidae." More recently,[clarification needed] the group[clarification needed] has been redefined under the PhyloCode as a node-based clade comprising the Canellales, Laurales, Magnoliales, and Piperales. Chase & Reveal have proposed "Magnoliidae" as the name used for the entire group of flowering plants, and the formal name "Magnolianae" for the group of four orders discussed here.[6]

APG system

The APG III (2009) and its predecessor systems did not originally use formal botanical names above the rank of order. Under those systems, larger clades were usually referred to by informal names, such as "magnoliids" (plural, not capitalized) or "magnoliid complex". The formal name in Linnean nomenclature was specified in a separate APG publication as the existing name "Magnolianae" Takht. (1967).[6] The APG III recognizes a clade within the angiosperms for the magnoliids. The circumscription is:

clade magnoliids
order Canellales
order Laurales
order Magnoliales
order Piperales
 
 
 

Chloranthales

 
 
magnoliids
 
 

Canellales

 
 

Piperales

 
 
 
 

Laurales

 
 

Magnoliales

 
 
 
 
 
 
 

monocots

 
 
 

Ceratophyllales

 
 

eudicots

 
 
 
 

The clade includes most of the basal groups of the angiosperms. This clade was formally named Magnoliidae in 2007 under provisions of the PhyloCode.[7]

Cronquist system

Flower of Magnolia obovata, showing multiple petals, stamens, and pistils.

The Cronquist system (1981) used the name Magnoliidae for one of six subclasses (within class Magnoliopsida = dicotyledons). In the original version of this system the circumscription was:[8]

Dahlgren and Thorne systems

Comparison table

Because of these difficulties and others, the synoptic table below imprecisely compares the definition of "magnoliid" groups in the systems of four authors. For each system, only orders are named in the table. All orders included by a particular author are listed and linked in that column. When a taxon is not included by that author, but was included by an author in another column, that item appears in unlinked italics and indicates remote placement. The sequence of each system has been altered from its publication in order to pair corresponding taxa between columns.

Comparison of the magnoliids across five systems
APG II system (2003) [9]
magnoliids 		Cronquist system[8]
Magnoliidae 		Dahlgren system[10]
Magnolianae 		Thorne system (1992)[11]
Magnolianae 		Thorne system (2000)[12]
Magnolianae
Laurales Laurales Laurales Magnoliales Magnoliales
Magnoliales Magnoliales Magnoliales
Annonales
Canellales Winterales
Piperales Lactoridales
Aristolochiales Aristolochiales
Piperales Piperales in Nymphaeanae
unplaced or in basal clades Chloranthales
Illiciales Illiciales
in Rosidae Rafflesiales in Rafflesianae in Rafflesianae
Nymphaeales in Nymphaeanae in Nymphaeanae in Nymphaeanae
Ceratophyllales in Ranunculidae
placed in eudicot clade Nelumbonales Nelumbonales
Ranunculales in Ranunculanae Berberidales
Papaverales
in Dilleniidae in Theanae Paeoniales

Economic uses

The magnoliids is a large group of plants, with many species that are economically important as food, drugs, perfumes, timber, and as ornamentals, among many other uses.

The avocado has been cultivated in the Americas for thousands of years.

One widely cultivated magnoliid fruit is the avocado (Persea americana), which is believed to have been cultivated in Mexico and Central America for nearly 10,000 years.[13] Now grown throughout the tropics, it probably originates from the Chiapas region of Mexico or Guatemala, where "wild" avocados may still be found.[14] The soft pulp of the fruit is eaten fresh or mashed into guacamole. The ancient peoples of Central America were also the first to cultivate several fruit-bearing species of Annona.[8] These include the custard-apple (A. reticulata), soursop (A. muricata), sweetsop or sugar-apple (A. squamosa), and the cherimoya (A. cherimola). Both soursop and sweetsop now are widely grown for their fruits in the Old World as well.[15]

Some members of the magnoliids have served as important food additives, such as black pepper, nutmeg, bay laurel and cinnamon. Oil of sassafras was formerly used as a key flavoring in both root beer and in sarsaparilla.[16] The primary ingredient responsible for the oil's flavor is safrole, but it is no longer used in either the United States or Canada. Both nations banned the use of safrole as a food additive in 1960 as a result of studies that demonstrated safrole promoted liver damage and tumors in mice.[17] Consumption of more than a minute quantity of the oil causes nausea, vomiting, hallucinations, and shallow rapid breathing. It is very toxic, and can severely damage the kidneys.[18] In addition to its former use as a food additive, safrole from either Sassafras or Ocotea cymbarum is also the primary precursor for synthesis of MDMA (methylenedioxymethamphetamine), commonly known as the drug ecstasy.[19]

Nutmeg fruits are a source of the hallucinogen myristicin.

Other magnoliids also are known for their narcotic, hallucinogenic, or paralytic properties. The Polynesian beverage kava is prepared from the pulverized roots of Piper methysticum, and has both sedative and narcotic properties.[15] It is used throughout the Pacific in social gatherings or after work to relax. Likewise, some native peoples of the Amazon take a hallucinogenic snuff made from the dried and powdered fluid exuded from the bark of Virola trees.[8] Another hallucinogenic compound, myristicin, comes from the spice nutmeg.[20] As with safrole, ingestion of nutmeg in quantities can lead to hallucinations, nausea, and vomiting, with symptoms lasting several days.[21] A more severe reaction comes from poisoning by rodiasine and demethylrodiasine, the active ingredients in fruit extract from Chlorocardium venenosum. These chemicals paralyze muscles and nerves, resulting in tetanus-like reactions in animals. The Cofán peoples of westernmost Amazon in Colombia and Ecuador use the compound as a poison to tip their arrows in hunting.[22]

Not all the effects of chemical compounds in the magnoliids are detrimental. In previous centuries, sailors would use Winter's Bark from the South American tree Drimys winteri to ward off the vitamin-deficiency of scurvy.[15] Today, benzoyl is extracted from Lindera benzoin (common spicebush) for use as a food additive and skin medicine, due to its anti-bacterial and anti-fungal properties.[23] Drugs extracted from the bark of Magnolia have long been used in traditional Chinese medicine. Scientific investigation of magnolol and honokiol have shown promise for their use in dental health. Both compounds demonstrate effective anti-bacterial activity against the bacteria responsible for bad breath and dental caries.[24][25] Several members of the family Annonaceae are also under investigation for uses of a group of chemicals called acetogenins. The first acetogenin discovered was uvaricin, which has anti-leukemic properties when used in living organisms. Other acetogenins have been discovered with anti-malarial and anti-tumor properties, and some even inhibit HIV replication in laboratory studies.[26]

Many magnoliid species produce essential oils in their leaves, bark, or wood. The tree Virola surinamensis (Brazilian "nutmeg") contains trimyristin, which is extracted in the form of a fat and used in soaps and candles, as well as in shortenings.[27] Other fragrant volatile oils are extracted from Aniba rosaeodora (bois-de-rose oil), Cinnamomum porrectum, Cinnamomum cassia, and Litsea odorifera for scenting soaps.[28] Perfumes also are made from some of these oils; ylang-ylang comes from the flowers of Cananga odorata, and is used by Arab and Swahili women.[15] A compound called nutmeg butter is produced from the same tree as the spice of that name, but the sweet-smelling "butter" is used in perfumery or as a lubricant rather than as a food.

See also

References

  1. ↑ Wu, J. Y.; Xue, J. Y.; Van De Peer, Y. (2021). "Evolution of NLR Resistance Genes in Magnoliids: Dramatic Expansions of CNLS and Multiple Losses of TNLS". Frontiers in Plant Science 12. doi:10.3389/fpls.2021.777157. PMID 34992620. 
  2. ↑ Botany Illustrated: Introduction to Plants Major Groups Flowering Plant Families. Thomson Science. 1984. p. 26. 
  3. ↑ Magallon, S; Gomez-Acevedo, S; Sanchez-Reyes, LL; Tania Hernandez-Hernandez, T (2015). "A metacalibrated time-tree documents the early rise of flowering plant phylogenetic diversity". New Phytologist 207: 437–453. doi:10.1111/nph.13264. 
  4. ↑ Zeng, Liping; Zhang, Qiang; Sun, Renran; Kong, Hongzhi; Zhang, Ning; Ma, Hong (24 September 2014). "Resolution of deep angiosperm phylogeny using conserved nuclear genes and estimates of early divergence times". Nature Communications 5 (4956). doi:10.1038/ncomms5956. PMID 25249442. Bibcode: 2014NatCo...5.4956Z. 
  5. ↑ International Code of Nomenclature for algae, fungi, and plants, Art. 16
  6. ↑ 6.0 6.1 Chase, M.W.; Reveal, J.L. (2009), "A phylogenetic classification of the land plants to accompany APG III", Botanical Journal of the Linnean Society 161 (2): 122–127, doi:10.1111/j.1095-8339.2009.01002.x 
  7. ↑ Cantino, Philip D.; James A. Doyle; Sean W. Graham; Walter S. Judd; Richard G. Olmstead; Douglas E. Soltis; Pamela S. Soltis; Michael J. Donoghue (2007). "Towards a phylogenetic nomenclature of Tracheophyta". Taxon 56 (3): E1–E44. doi:10.2307/25065865. 
  8. ↑ 8.0 8.1 8.2 8.3 Cronquist, Arthur (1981). An Integrated System of Classification of Flowering Plants. New York: Columbia University Press. ISBN 0-231-03880-1. https://archive.org/details/integratedsystem0000cron. 
  9. ↑ Angiosperm Phylogeny Group (2003). "An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG II". Botanical Journal of the Linnean Society 141 (4): 399–436. doi:10.1046/j.1095-8339.2003.t01-1-00158.x. 
  10. ↑ Dahlgren, R.M.T. (1980). "A revised system of classification of angiosperms". Botanical Journal of the Linnean Society 80 (2): 91–124. doi:10.1111/j.1095-8339.1980.tb01661.x. 
  11. ↑ Thorne, R. F. (1992). "Classification and geography of the flowering plants". Botanical Review 58 (3): 225–348. doi:10.1007/BF02858611. Bibcode: 1992BotRv..58..225T. 
  12. ↑ Thorne, R. F. (2000). "The classification and geography of the flowering plants: Dicotyledons of the class Angiospermae". Botanical Review 66 (4): 441–647. doi:10.1007/BF02869011. Bibcode: 2000BotRv..66..441T. 
  13. ↑ "Angiosperms". The New Encyclopædia Britannica. 13. 1994. pp. 634–645. 
  14. ↑ Kopp, Lucille E. (1966). "A taxonomic revision of the genus Persea in the Western Hemisphere. (Persea-Lauraceae)". Memoirs of the New York Botanical Garden 14 (1): 1–117. 
  15. ↑ 15.0 15.1 15.2 15.3 Heywood, V. H., ed (1993). Flowering Plants of the World (updated ed.). New York: Oxford University Press. pp. 27–42. ISBN 0-19-521037-9. https://archive.org/details/floweringplantso0000unse/page/27. 
  16. ↑ Hester, R. E.; Roy M. Harrison (2001). Food safety and food quality. Royal Society of Chemistry. p. 118. ISBN 0-85404-270-9. 
  17. ↑ Hayes, Andrew Wallace (2001). Principles and Methods of Toxicology (4th ed.). CRC Press. p. 518. ISBN 1-56032-814-2. 
  18. ↑ "Sassafras oil overdose". New York Times. http://health.nytimes.com/health/guides/poison/sassafras-oil-overdose/overview.html. 
  19. ↑ "MDMA and MDA producers using Ocotea cymbarum as a precursor". Microgram Bulletin XXXVIII (11). 2005. http://www.usdoj.gov/dea/programs/forensicsci/microgram/mg1105/mg1105.html. Retrieved 2008-07-13. 
  20. ↑ Shulgin, Alexander T. (1966-04-23). "Possible implication of myristicin as a psychotropic substance". Nature 210 (5034): 380–384. doi:10.1038/210380a0. PMID 5336379. Bibcode: 1966Natur.210..380S. 
  21. ↑ Panayotopoulos, D. J.; D. D. Chisholm (1970). "Hallucinogenic effect of nutmeg". British Medical Journal 1 (5698): 754. doi:10.1136/bmj.1.5698.754-b. PMID 5440555. 
  22. ↑ Kostermans, A. J.; Homer V. Pinkley; William L Stern (1969). "A new Amazonian arrow poison: Ocotea venenosa". Botanical Museum Leaflets, Harvard University 22 (7): 241–252. doi:10.5962/p.168371. 
  23. ↑ Zomlefer, Wendy B. (1994). Guide to Flowering Plant Families. Chapel Hill: University of North Carolina Press. pp. 29–39. ISBN 0-8078-2160-8. 
  24. ↑ Greenberg, M; P. Urnezis; M. Tian (2007). "Compressed mints and chewing gum containing magnolia bark extract are effective against bacteria responsible for oral malodor". Journal of Agricultural and Food Chemistry 55 (23): 9465–9469. doi:10.1021/jf072122h. PMID 17949053. 
  25. ↑ Chang, B; Lee Y; Ku Y; Bae K; Chung C. (1998). "Antimicrobial activity of magnolol and honokiol against periodontopathic microorganisms". Planta Medica 64 (4): 367–369. doi:10.1055/s-2006-957453. PMID 9619121. 
  26. ↑ Pilar Rauter, Amélia; A. F. Dos Santos; A. E. G. Santana (2002). "Toxicity of Some species of Annona Toward Artemia Salina Leach and Biomphalaria Glabrata Say". Natural Products in the New Millennium: Prospects and Industrial Application. Springer Science+Business Media. pp. 540 pages. ISBN 1-4020-1047-8. https://books.google.com/books?id=4rrC7c_6OUoC&pg=PA264. Retrieved 2008-07-12. 
  27. ↑ Pereira Pinto, Gerson (1951). "Contribuição ao estudo químico do Sêbo de Ucuúba". Boletim Técnico do Instituto Agronômico do Norte 23: 1–63. 
  28. ↑ Kostermans, A. J. G. H. (1957). "Lauraceae". Communication of the Forest Research Institute, Indonesia 57: 1–64. 

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