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Gnetum

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Gnetum
Gnetum macrostachyum in Thailand
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Gymnospermae
Division: Gnetophyta
Order: Gnetales
T.M.Fries
Family: Gnetaceae
Lindleyx
Genus: Gnetum
L.
Type species
Gnetum gnemon
Map showing the range of Gnetum
Distribution
Synonyms[1]
  • Gnemon Rumph. ex Kuntze
  • Thoa Aubl.
  • Abutua Lour.
  • Arthostema Neck.

Gnetum is a genus of gymnosperms, the sole genus in the family Gnetaceae within the Gnetophyta. They are tropical evergreen trees, shrubs and lianas. Unlike other gymnosperms, they possess vessel elements in the xylem. Some species have been proposed to have been the first plants to be insect-pollinated as their fossils occur in association with extinct pollinating scorpionflies.[2] Molecular phylogenies based on nuclear and plastid sequences from most of the species indicate hybridization among some of the Southeast Asian species. Fossil-calibrated molecular-clocks suggest that the Gnetum lineages now found in Africa, South America and Southeast Asia are the result of ancient long-distance dispersal across seawater.[3][4]

Their leaves are rich in bioactive compounds such as flavonoids and stilbenes. Of the species studied so far, Gnetum have photosynthetic and transpiration capacities which are considerably lower than those of other seed plants, due to the absence of multiple chloroplast genes essential for photosynthesis, a trait they seem to share with the other living members of Gnetophyta, Ephedra and Welwitschia, as well as conifers.[5] This plant is a climbing plant that uses its arial roots to wrap around trees in order to get to the sun light. It is a vining plant that you would rarely see as a shrub or a tree. They are found in warmer and tropical climates. There are over 50 different species of Gnetum.

Species

Phylogeny of Gnetum[6]

subsection Araeognemones

subsection Micrognemones

section Gnetum

section Scandentia

subsection Gnemonoides

subsection Stipitati

subsection Sessiles

Uses

Many Gnetum species are edible, with the seeds being roasted, and the foliage used as a leaf vegetable.[7] The plant is harvested and used for a good source of fiber. There is no sense of danger in consuming the fruit or the seeds.There is also a study done on the plant to see if it has any medicinal properties. The study has to do with platelets and nuclear blood cells.The family Gnetaceae is well known as a rich source of plant-derived stilbenoids as well as Cyperaceae, Dipterocarpaceae, Leguminosae and Vitaceae.

Endangered

Some species of Gnetum are in danger of dying out. The habitats are being removed with the trees being cut down to create industry. The tropical rainforest are being destroyed so many of the species are going extinct such as Gnetum oxycarpum. The rainforest are being torn down and being turned into farmland. Gnetum live in only a small part of the rainforest.

Taxonomy

  • Kingdom: Plantae
  • Division: Gnetophyta
  • Class: Gnetopsida
  • Order: Gnetales
  • Family: Gnetaceae    Gnetums
  • Genus: Gnetum
  • Species: macrostachyum Hook. f.
  • Residential: Native

Leaves, Stems, and Root

Gnetum has oval shaped leaves, that are not waxy. With veining going through the leaves. The stems are long thick stems that are able to bend when vining. The roots are thick arial roots that attach to the forest floor as well as the bark of trees in order to climb up the branches.

Fruit, seed, and Flower

The flowers are a star shaped flower that come in a variety of reds and pinks. The fruits are small round fruits that are green when not ripe then turn red when they are ready to be picked. The seeds are a round seed that is a light brown in the middle of the plant.

References

  1. ^ Kew World Checklist of Selected Plant Families
  2. ^ Ren D, Labandeira CC, Santiago-Blay JA, Rasnitsyn A, Shih CK, Bashkuev A, Logan MA, Hotton CL, Dilcher D. (2009). Probable Pollination Mode Before Angiosperms: Eurasian, Long-Proboscid Scorpionflies. Science, 326 (5954), 840-847. doi:10.1126/science.1178338
  3. ^ Won H, Renner SS: The internal transcribed spacer of nuclear ribosomal DNA in the gymnosperm Gnetum. Molecular Phylogenetics and Evolution 2005, 36:581-597. doi:10.1016/j.ympev.2005.03.011
  4. ^ Won, H., and S. S. Renner. 2006. Dating dispersal and radiation in the gymnosperm Gnetum (Gnetales) – clock calibration when outgroup relationships are uncertain. Systematic Biology 55(4): 610-622. doi:10.1080/10635150600812619
  5. ^ Significance of Photosynthetic Characters in the Evolution of Asian Gnetum (Gnetales)
  6. ^ Hou, Chen; Humphreys, Aelys M.; Thureborn, Olle; Rydin, Catarina (April 2015). "New insights into the evolutionary history of Gnetum (Gnetales)". Taxon. 64 (2): 239–253. doi:10.12705/642.12.
  7. ^ Hoe, V.B. and Siong, K.H., "The Nutritional Value of Indigenous Fruits and Vegetables in Sarawak,"Asia-Pacific Journal of Clinical Nutrition, Vol. 8, no. 1, 1998, pp 24-31
Wikimedia Commons has media related to Gnetum.
  1. ^ "Renaissance", Wikipedia, 2021-12-08, retrieved 2021-12-15
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