Adansonia

Adansonia
Adansonia digitata in Tanzania
Scientific classification
Kingdom: Plantae
Clade: Angiosperms
Clade: Eudicots
Clade: Rosids
Order: Malvales
Family: Malvaceae
Subfamily: Bombacoideae
Genus:Adansonia
L. [1]
Species

See Species section

Adansonia is a genus of deciduous trees known as baobabs. They are found in arid regions of Madagascar, mainland Africa, Arabia, and Australia. The generic name honours Michel Adanson, the French naturalist and explorer who described Adansonia digitata .

Of the nine species accepted as of April 2018, six are native to Madagascar, two are native to mainland Africa and the Arabian Peninsula, and one is native to Australia. One of the mainland African species also occurs on Madagascar, but it is not a native of that island. It was introduced in ancient times to south Asia and during the colonial era to the Caribbean. It is also present in the island nation of Cape Verde. [2] The ninth species was described in 2012, and is found in upland populations of southern and eastern Africa. [3] The African and Australian baobabs are almost identical despite having separated more than 100 million years ago, probably by oceanic dispersal. [4]

In the early 21st century, baobabs in Southern Africa began to die off rapidly from a cause yet to be determined. Scientists believe it is unlikely that disease or pests were able to kill many trees so rapidly, while some estimated that the die-off was a result of dehydration from global warming. [5] [6]

Description

Baobabs reach heights of 5 to 30 m (16 to 98 ft) and have trunk diameters of 7 to 11 m (23 to 36 ft).[ citation needed ] The Glencoe baobab, a specimen of A. digitata in Limpopo Province, South Africa, was considered to be the largest living individual, with a maximum circumference of 47 m (154 ft) [7] and a diameter of about 15.9 m (52 ft). The tree has since split into two parts, so the widest individual trunk may now be that of the Sunland baobab, or Platland tree, also in South Africa. The diameter of this tree at ground level is 9.3 m (31 ft) and its circumference at breast height is 34 m (112 ft). [8]

Adansonia trees produce faint growth rings, probably annually, but they are not reliable for aging specimens, because they are difficult to count and may fade away as the wood ages. Radiocarbon dating has provided data on a few individuals of A. digitata. The Panke baobab in Zimbabwe was some 2,450 years old when it died in 2011, making it the oldest angiosperm ever documented, and two other trees — Dorslandboom in Namibia and Glencoe in South Africa — were estimated to be approximately 2,000 years old. [9] Another specimen known as Grootboom was dated and found to be at least 1275 years old. [8] [10] Greenhouse gases, climate change, and global warming appear to be factors reducing baobab longevity. [5]

Species

Adansonia grandidieri , Madagascar

Species include: [11]

Habitat

The Malagasy species are important components of the Madagascar dry deciduous forests. Within that biome, Adansonia madagascariensis and A. rubrostipa occur specifically in the Anjajavy Forest, sometimes growing out of the tsingy limestone itself. A. digitata has been called "a defining icon of African bushland". [10]

Ecology

Baobabs store water in the trunk (up to 120,000 litres or 32,000 US gallons) to endure harsh drought conditions. [13] All occur in seasonally arid areas, and are deciduous, shedding their leaves during the dry season. Across Africa, the oldest and largest baobabs began to die in the early 21st century, likely from a combination of drought and rising temperatures. [5] The trees appear to become parched, then become dehydrated and unable to support their massive trunks. [6]

Baobabs are important as nest sites for birds, in particular the mottled spinetail [14] and four species of weaver. [15]

Food uses

The cut fruit from Mozambique

The fruit has a velvety shell and is about the size of a coconut, weighing about 1.5 kilograms (3.3 lb), but is not as globular. It has an acidic, tart, citrus flavor. [16] It is a good source of vitamin C, potassium, carbohydrates, and phosphorus. [17]

Baobab powder

The dried fruit powder of Adansonia digitata,baobab powder, contains about 12% water and modest levels of various nutrients, including carbohydrates, pectin, riboflavin, calcium, magnesium, potassium, iron, and phytosterols, with low levels of protein and fats. [16] [18] [19] [20] Vitamin C content, described as variable in different samples, was in a range of 74 to 163 milligrams (1.14 to 2.52 gr) per 100 grams (3.5 oz) of dried powder. [16] The powdered white pulp may be used as a "thickener in jams and gravies [...] or a tangy flavor addition to hot sauces". [19]

In the European Union (EU), prior to commercial approval, baobab fruit powder was not available for use as a food ingredient, as legislation from 1997 dictated that foods not commonly consumed in the EU would have to be formally approved first. In 2008, baobab dried fruit pulp was authorized in the EU as a safe food ingredient, [21] and later in the year was granted GRAS (generally recognized as safe) status in the United States. [22]

Regionally

In Tanzania, the dry pulp of A. digitata is added to sugarcane to aid fermentation in beermaking. [23] In Angola, the dry fruit is usually boiled and the broth is used for juices or as the base for a type of ice cream known as gelado de múcua. In Zimbabwe, the fruit is used in traditional food preparations which include "eating the fruit fresh or crushed crumbly pulp to stir into porridge and drinks".[ citation needed ] Malawi women have set up commercial ventures harvesting the baobab to earn their children's school fees.

Fresh fruit, seeds, leaves

The fruit pulp and seeds of A. grandidieri [24] and A. za are eaten fresh. [25] The fresh fruit is said to taste like sorbet. [26] The seeds of some species are a source of vegetable oil, [24] [25] and their leaves may be eaten as a leaf vegetable. [10]

Other uses

Some baobab species are sources of fiber, dye, and fuel. Indigenous Australians used the native species A. gregorii for several products, making string from the root fibers and decorative crafts from the fruits. [27]

References

  1. "Genus: Adansonia L". Germplasm Resources Information Network. United State Department of Agriculture. 2008-11-12. Retrieved 2011-01-14.
  2. Wickens, G. E.; Lowe, P. (2008). The Baobabs: Pachycauls of Africa, Madagascar and Australia. Berlin, Germany; New York, NY: Springer Verlag. ISBN   978-1-4020-6430-2. OCLC   166358049.
  3. 1 2 Pettigrew, J. D.; et al. (2012). "Morphology, ploidy and molecular phylogenetics reveal a new diploid species from Africa in the baobab genus Adansonia (Malvaceae: Bombacoideae)" (PDF). Taxon. 61: 1240–1250.
  4. Baum DA, Small RL, Wendel JF (1998). "Biogeography and floral evolution of baobabs (Adansonia, Bombacaceae) as inferred from multiple data sets" (PDF). Syst Biol. 47 (2): 181–207.
  5. 1 2 3 Ed Yong (11 June 2018). "Trees That Have Lived for Millennia Are Suddenly Dying The oldest baobabs are collapsing, and there's only one likely explanation". The Atlantic. Retrieved 12 June 2018.
  6. 1 2 Rachel Nuwer (12 June 2018). "Last March of the 'Wooden Elephants': Africa's Ancient Baobabs Are Dying". New York Times. Retrieved 2018-06-13.
  7. "Big Baobab Facts". Archived from the original on 2008-01-06. Retrieved 2008-01-08.
  8. 1 2 Patrut, A., et al. (2010). Fire history of a giant African baobab evinced by radiocarbon dating. Radiocarbon 52(2), 717-26.
  9. Adrian Patrut et al. (2018) The demise of the largest and oldest African baobabs. Nature Plants 4: 423–426. DOI: 10.1038/s41477-018-0170-5
  10. 1 2 3 "Adansonia digitata (baobab)". Royal Botanic Gardens, Kew. Retrieved 2014-06-08.
  11. "GRIN Species Records of Adansonia". Germplasm Resources Information Network. United State Department of Agriculture. Retrieved 2011-01-14.
  12. Gardner, Simon; Sidisunthorn, Pindar; Lai, Ee May (2011). Heritage Trees of Penang. Penang: Areca Books. ISBN   978-9-675-71906-6.
  13. "The Baobab tree in Senegal". Archived from the original on 2008-10-04. Retrieved 2008-10-01.
  14. "Species text in The Atlas of Southern African Birds" (PDF). Retrieved 2014-10-30.
  15. "Weavers breeding in baobabs". Animal Demography Unit, Department of Biological Sciences, University of Cape Town, South Africa. Retrieved 2014-10-30.
  16. 1 2 3 UK Advisory Committee on Novel Foods and Processes (July 2008). "Baobab dried fruit pulp. EC No. 72; August 2006: Application from PhytoTrade Africa to approve baobab dried fruit pulp as a novel food ingredient. Authorised July 2008". UK Food Standards Agency. Retrieved 2012-06-03.
  17. "Baobab: Benefits, nutrition, dietary tips, and risks". Medical News Today. Retrieved 2018-06-20.
  18. Osman, M. A. (2004). "Chemical and nutrient analysis of baobab (Adansonia digitata) fruit and seed protein solubility". Plant Foods Hum Nutr. 59 (1): 29–33. doi:10.1007/s11130-004-0034-1. PMID   15675149.
  19. 1 2 "New exotic fruit to hit UK shops". BBC. 2008-07-15. Archived from the original on March 7, 2009. Retrieved 2008-07-15.
  20. Chadare, F. J.; et al. (2009). "Baobab food products: a review on their composition and nutritional value". Crit Rev Food Sci Nutr. 49 (3): 254–74. doi:10.1080/10408390701856330. PMID   19093269.
  21. "Baobab dried fruit pulp". UK Food Standards Agency. 2008. Retrieved 2012-06-03.
  22. "GRAS Notice No. GRN 273". US Food and Drug Administration. 25 July 2009. Retrieved 3 May 2018.
  23. Sidibe, M., et al. Baobab, Adansonia digitata L. Volume 4 of Fruits for the Future. International Centre for Underutilised Crops, 2002.
  24. 1 2 Ambrose-Oji, B. and N. Mughogho. 2007. Adansonia grandidieri Baill. Archived 2014-04-07 at the Wayback Machine . In: van der Vossen, H. A. M. and G. S. Mkamilo (Eds). PROTA 14: Vegetable oils/Oléagineux. PROTA, Wageningen, Netherlands.
  25. 1 2 Ambrose-Oji, B. and N. Mughogho. 2007. Adansonia za Baill. Archived 2015-04-02 at the Wayback Machine . In: van der Vossen, H. A. M. and G. S. (Eds). PROTA 14: Vegetable oils/Oléagineux. PROTA, Wageningen, Netherlands.
  26. "Adansonia gregorii". Australian Tropical Rainforest Plants. Retrieved 2014-06-08.
  27. "Dance of the baob". The Australian Women's Weekly . National Library of Australia. 2 February 1966. p. 26. Retrieved 11 January 2012.

Further reading