Tylosema
{{Short description|Genus of legumes}}
{{Automatic taxobox
|image = Tylosema esculentum.png
|image_caption = Marama bean
|display_parents = 2
|taxon = Tylosema
|authority = (Schweinf.) Torre & Hillc.
|type_species = Tylosema fassoglensis
|type_species_authority = (Kotschy ex Schweinf.) Torre & Hillc.
|subdivision_ranks = Species
|subdivision = 4–5; see text
|range_map = Tylosema distribution.svg
|range_map_caption = The range of Tylosema.
}}
The genus Tylosema is in the plant family Fabaceae and encompasses four accepted species of perennial legumes native to southern and central Africa. These are semi-woody viniferous plants broadly distributed from Sudan and Ethiopia south to Angola and South Africa.{{cite journal | title = Functional Heterostyly in Tylosema esculentum (Caesalpinioideae) | year = 2002 |vauthors=Hartley ML, Tshamekeng E, Thomas SM | journal = Annals of Botany | volume = 89 | issue = 1 | pages = 67–76 | url= | doi = 10.1093/aob/mcf006 | pmid=12096820 | pmc=4233773}} Coetzer and RossCoetzer, L. A., and J. H. Ross. 1977. Tylosema. In Ross, J. H., ed., Fl. Southern Africa 16(2):61-64 originally described four Tylosema species:
Species
There are four documented species within the genus Tylosema (Schweinf.) Torre & Hillc.:{{cite web | url = http://www.ildis.org/LegumeWeb?version~10.01&genus~Tylosema&species~ | title = ILDIS LegumeWeb entry for Tylosema | author = | website = International Legume Database & Information Service | publisher = Cardiff School of Computer Science & Informatics | access-date = 8 May 2014 }}{{cite web | url = http://www.ars-grin.gov/cgi-bin/npgs/html/splist.pl?16906 | title = GRIN species records of Tylosema | author = USDA, ARS, National Genetic Resources Program | website = Germplasm Resources Information Network—(GRIN) [Online Database] | publisher = National Germplasm Resources Laboratory, Beltsville, Maryland | access-date = 5 May 2014 }}{{cite web | url = http://www.theplantlist.org/1.1/browse/A/Leguminosae/Tylosema/ | title = The Plant List entry for Tylosema | date = 2013 | website = The Plant List | publisher = Royal Botanic Gardens, Kew and the Missouri Botanical Garden | access-date = 5 May 2014 }}
- Tylosema argentea (Chiov.) Brenan
- Tylosema esculentum (Burch.) A.Schreib.—Marama bean
- Tylosema fassoglense (Kotschy ex Schweinf.) Torre & Hillc.
- Tylosema humifusa (Pichi-Serm. & Roti-Michel) Brenan
Proposed species:
- Tylosema angolense P.Silveira & S.Castro{{cite journal | title = Systematic studies in Tylosema (Leguminosae) | year = 2005 |vauthors=Castro S, Silveira P, Pereira Coutinho A, Figueiredo E | journal = Botanical Journal of the Linnean Society | volume = 147 | issue = 1 | pages = 99–115 | doi = 10.1111/j.1095-8339.2005.00353.x | doi-access = free }}
Common names
Creeping bauhinia (English), Gwangwandiza (Shona), Marama bean, gemsbok bean, tamani berry (English), Morama bean, gami (Khoi), Mubopo (Shona), Mutukutupasi (Shona), Umbama or Umdabule (Ndebele).{{Cite journal|title = The morama bean (Tylosema esculentum): A potential crop for southern Africa.|last1 = Jackson|first1 = Jose|date = 2010|journal = Advances in Food and Nutrition Research |volume=61 |issue=5 |pages=187–246 |doi = 10.1016/B978-0-12-374468-5.00005-2|pmid = 21092905|last2 = Kwaku G. Duodu, Mette Holse, Lima de Faria, Margarida D, Danie Jordaan, Walter Chingwaru, Aase Hansen, Avrelija Cencic, Martha Kandawa-Schultz, and Selalelo M. Mpotokwane.}}{{Cite web|url = http://www.zimbabweflora.co.zw/speciesdata/genus.php?genus_id=691|title = Tylosema Torre & Hillc.|date = October 12, 2013|access-date = October 17, 2014|website = Flora of Zimbabwe|publisher =Hyde, M.A., Wursten, B.T., Ballings, P. & Coates Palgrave, M. }}
Habitat
Habitat for Tylosema species is diverse and particular to each species. T. esculentum is found mostly on sandy plains, while T. fassoglense can be found from open grassland to desert to woodlands to roadsides. All species are found from low to moderate altitude.
Tylosema species grow in mostly sandy soils with low rainfall and can tolerate scorching heat and long-term drought. Typical daily high temperatures average 37 °C during growing season and radiation frequently exceeds 2000 μmol m−2 s−1.{{Cite journal|title = Adaptation of photosynthesis in marama bean - Tylosema esculentum (burchell A.Schreib.) to a high temperature, high radiation, drought-prone environment.|last1 = Mitchell|first1 = RAC|date = 2005|journal = Plant Physiology and Biochemistry |volume=43 |issue=10 |pages=969–76 |doi = 10.1016/j.plaphy.2005.08.009|pmid = 16310366|last2 = Keys AJ, Madgwick, PJ, Parry MAJ, and DW Lawlor.|title-link = Annelis Schreiber| bibcode=2005PlPB...43..969M }} Whereas many legumes can fix atmospheric nitrogen, all Tylosema species are non-nodulating.
Vegetation is a climbing vine, with some species reaching up to 6 m long. Herbaceous stems trail or climb, originating from a large underground tuber that is visible above the soil surface. Leaves are simple and 2-lobed. Forked tendrils are usually present. Inflorescence is a lateral raceme. Flowers are yellow, bisexual, heterostylous, with 5 petals. Pods are large, woody and have 1 or 2 seeds. Herostyly, or flower polymorphism, occurs in all species of Tylosema, although it is unknown in the rest of the family Leguminosae.
Phylogeny
Tylosema species are in the family Leguminosae, the third largest family of flowering plants (Doyle and Luckow, 2003), in the subfamily Cercidoideae. The type species for the Tylosema genus is T. fassoglense.
The phylogeny of Tylosema is somewhat disputed.{{Cite book|title = Legumes of the World|last = Lewis, G., Schrire, B., Mackinder, B. & Lock, M. (eds.)|publisher = Kew: Royal Botanic Gardens.|year = 2005|pages = 57–67|chapter = Tribe Cercideae. Lewis, G. & Forest, F.}}{{Cite journal|title = Evolution and diversity of pollen morphology in tribe cercideae (leguminosae).|last = Banks, Hannah, Félix Forest, and Gwilym Lewis.|date = 2014|journal = Taxon |volume=63 |issue=2 |pages=299–314 |doi = 10.12705/632.37}}{{Cite journal|title = Phylogenetic patterns and diversification in the caesalpinioid legumes.|last = Bruneau, Anne, Marjorie Mercure, Gwilym P. Lewis, and Patrick S. Herendeen.|date = 2008|journal = Botany |volume=86 |issue=7 |pages=697–718 |doi = 10.1139/b08-058}} This is in part because it has not been widely collected or studied. Although previously located in the Bauhinia genus, now Tylosema has been established as its own genus and is strongly supported as monophyletic.{{Cite journal|title = The genus Bauhinia s.l. (leguminosae): A phylogeny based on the plastid trnL–trnF region.|last = Sinou, Carole, Fé Forest, Gwilym P. Lewis, and Anne Bruneau.|date = 2009|journal = Botany |volume=87 |issue=10 |pages=947–60 |doi = 10.1139/b09-065}}
Wunderlin has proposed a reorganization of the tribe Cercideae wherein 12 genera are placed into two subtribes, Cercinidae and Bauhiniinae. Bauhiniinae is divided into two clades, the first is poorly resolved and includes the genera Bauhinia, Brenierea and Piliostigma. The second clade comprises the genera Tylosema, Barklya, Gigasiphon, Lysiphyllum, Phanera, and Schnella.{{Cite journal|title = Reorganization of the Cercideae (Fabaceae: Caesalpinioideae).|last = Wunderlin|first = RP|date = 2010|journal = Phytoneuron |volume=2010 |issue=48 |pages=1–5 }}
Biology and use
In Botswana and Namibia T. esculentum, or Morama bean, is a staple food of the Khoisan people but plants have not been established for cultivation. The beans have high protein content (30-39%) and high oil content (36-43%)and are eaten after boiling or roasting.Taatsu, Kapewangolo Petrina. 2010. Biochemical characteristics of marama bean (Tylosema esculentum). Master's degree thesis. University of Namibia. http://repository.unam.na/handle/11070/473 Beans also have significant levels of calcium, iron, zinc, phosphate, magnesium, and B vitamins including folate.{{Cite journal|title = Chemical composition of marama bean (Tylosema esculentum)—A wild African bean with unexploited potential.|last1 = Holse|date = 2010|journal = Journal of Food Composition & Analysis |volume=23 |issue = 6|pages=648–57 |doi = 10.1016/j.jfca.2010.03.006|last2 = Husted S., and A. Hansen.}}
Preliminary research indicates that seeds of T. esculentum have no physiological dormancy, although germination is improved by scarification.{{Cite journal|title = Germination and emergence of the hard seed coated Tylosema esculentum (Burch) A.Schreib. in response to different pre-sowing seed treatments.|last1 = Travlos|first1 = IS|date = 2007|journal = Journal of Arid Environments |volume=68 |issue=3 |pages=501–507 |doi = 10.1016/j.jaridenv.2006.07.001|last2 = Economou G, and AI Karamanos.|title-link = Annelis Schreiber| bibcode=2007JArEn..68..501T }} It is disputed as to whether Morama beans exhibit antiviral and antimicrobial properties.{{Cite journal|title = Tylosema esculentum (marama) tuber and bean extracts are strong antiviral agents against rotavirus infection.|last1 = Chingwaru|first1 = W|date = 2011|journal = Evidence-Based Complementary and Alternative Medicine |volume=8 |issue=1 |pages=284795 |doi = 10.1155/2011/284795 |pmid = 21423688|pmc = 3057194|last2 = Majinda RT, Yeboah SO, Jackson J, Kapewangolo PT, Kandawa-Schulz M, and A Cencic.| doi-access=free }}{{Cite journal|title = Tylosema esculentum extractives and their bioactivity.|last1 = Mazimba|first1 = O.|date = 2011|journal = Bioorganic & Medicinal Chemistry |volume=19 |issue=17 |pages=5225–30 |doi = 10.1016/j.bmc.2011.07.006|pmid = 21813280|last2 = Majinda RT, Modibedi C, Masesane IB, Cencič A, and W Chingwaru.}}
Research shows that T. esculentum is both drought avoidant and drought tolerant, but this has not been measured in other Tylosema species.{{Cite journal|title = The water relations and some drought tolerance mechanisms of the marama bean.|last1 = Karamanos|first1 = AJ|date = 2012|journal = Agronomy Journal |volume=104 |issue=1 |pages= 65–72 |doi = 10.2134/agronj2011.0194|last2 = Travlos, IS.| bibcode=2012AgrJ..104...65K }}