| Gnetum africanum | |
|---|---|
 | |
| Gnetum africanum, from the coastal rainforest ofCameroon. | |
Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Gymnospermae |
| Division: | Gnetophyta |
| Order: | Gnetales |
| Family: | Gnetaceae |
| Genus: | Gnetum |
| Species: | G. africanum |
| Binomial name | |
| Gnetum africanum | |
| Synonyms[2] | |
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Gnetum africanum (eru orAfrican jointfir) is a species of vine native to tropicalAfrica.[3][4][5] Though bearing leaves, the genusGnetum aregymnosperms, related topine and otherconifers.[6][7][8]
Gnetum africanum has numerous common names and is grown in various countries across Africa, including:Cameroon (Eru,okok,m'fumbua, orfumbua),Angola (KoKo),Nigeria (ukazi, "okazi", orafang),Gabon (Nkumu),Central African Republic (KoKo), Congo (KoKo), and theDemocratic Republic of Congo (m'fumbua orfumbua).Gnetum africanum has also been referred to as a form of 'wild spinach' in English.[9]
Gnetum africanum is traditionally a wild vine and is considered to be a wild vegetable.[10] It is a perennial that grows approximately 10 metres long, with thick papery-like leaves growing in groups of three. The leaves may grow approximately 8 cm long, and at maturity the vine will produce small cone-like reproductive structures. The seeds of the vine resemble a fleshy fruit, sized 10–15 mm × 4–8 mm, and are red-orange in colour when fully ripe.[11]
Gnetum africanum may also be known asG. buchholzianum, and is one of the two vine species from the Gnetum genus that grown in Africa.[12] There are currently nogene banks forGnetum africanum, but approximately 19 varieties of the species have been planted in Cameroon'sLimbe Botanic Garden to begin a gene bank.[12]
Gnetum africanum is found mainly in the humid tropical forest regions ofCentral African Republic,Cameroon,Gabon,Republic of the Congo,Democratic Republic of the Congo andAngola. It has been found in primary and secondary semi-deciduous humid forests, both in dense and sunny transitional savannah locations, ranging from sea-level to 1200 meter altitude. The shade tolerant vine does not grow well in direct sunlight and can be found climbing on middle and under-story trees.[3][13]
This vine will grow in all seasons and typically spreads along forest floors. The vine grows in two ways: through rhizomes, or through new shoots that grow where the stem has been cut.[11] AsGnetum africanum is a wild forest vine, it tends to grow best in shaded areas.[9] Input requirements forGnetum africanum have not yet been established, and nutrient requirements are currently unknown as well.[10] This is likely due to the fact that the vine is traditionally a wild vegetable. The plant has now been domesticated and grown for subsistence and commercial use among the Ibibio, Efik and Annang people of Nigeria. However, it has been noted that the vine grows best in well-shaded areas similar to that of a forest, as too much sunlight can burn the vine and produce substandard leaves for selling purposes. It has also been noted that the vine does not grow particularly well in very moist conditions such as marshes and swamps.[10]
Gnetum africanum has been found to be negatively impacted if grown on or next totermite infected wood or trees.[10] However, the productivity of the vine appears to be resistant to a significant proportion of diseases.[11] The vine is largely understudied, and more research is needed to verify plant susceptibility and resilience to viruses, diseases, and fungi.Gnetum africanum depletion is largely associated with tree felling and overexploitative forestry practices.Overexploitation is partly caused by unsustainable forest clearing practices throughout regions in Africa.[14]
SinceGnetum africanum grows best in shaded areas it could be used as a complementary crop on tree farms. Specifically, it has been suggested that the vine could be used as a complementary crop for rubber and oil trees.[11] However, the necessity for shaded, but not excessively moist, conditions may make it difficult for poor farmers to growGnetum africanum if they lack access to suitable lands. However, sinceGnetum africanum grows via rhizomes it is not labour-intensive, therefore allowing farmers to focus physical capital elsewhere.
Sustainable cultivation practices, such as harvesting the leaves regularly rather than uprooting the whole vine, allows for a more viable supplementary income throughout the year. The FAO has found that the vine is easier to reproduce by cuttings than by growing from seeds.[12]
The Centre for International Forestry Research (CIFOR) has been working with women to create sustainable cultivation practices ofGnetum africanum, as well asforest restoration techniques.[5] Specifically, near Lekie, Cameroon, CIFOR has been helping the women remove an invasive plant species (kodengui), and replacing it withGnetum africanum, in order to discourage regrowth of the invasive species and utilize the area for a more sustainable resource.
Subsistence agriculturalists in Cameroon may be able to improve their nutritional, environmental, social, and economic situations by growing this vine. Nutrition can be improved by using the plant for medicinal purposes as well as through edible consumption.[5]Primarily,Gnetum africanum leaves are used as a vegetable for soups and stews, commonly callederu soup, okazi soup orafang soup.[12] The leaves of the vine are sold in markets throughout the year and may be used in soups and stews or eaten raw. The leaves may further be used as a remedy fornausea, sore throats, or as a dressing for warts. The stem of the plant may also be eaten for medicinal purposes, including the reduction of pain during childbirth.[5] Furthermore,Gnetum africanum produces a root tuber that may be used as a source offamine food, and is similar to that of a yam.[11] Finally, the seeds of the vine may also be eaten cooked.[9]
Gnetum africanum is a good source of protein and is strong in essential and non-essential amino acids. It is high inglutamic acid,leucine, andaspartic acid, with low levels ofhistidine, andcysteine, while there appears to be trace amounts oftryptophan in the plant. The content of amino acids found inGnetum africanum is similar to recommended levels by the FAO. It has also been found that the levels ofiodine are also high in the vine. Fibre levels average approximately 33.4 g/100 g of driedGnetum africanum leaves, while recommended daily intake of fibre is 30 g.Gnetum africanum has been noted as an anti-inflammatory, anticarcinogenic and antioxidant.[9]
Economically,Gnetum africanum can be used as a means to maintain a supplemental income as it is available throughout the year,[15] and may be used as a form of supplementary income for rural farmers in Cameroon. Healthy leaves with a thick wax-like texture are preferred in markets and will receive the highest value;Gnetum africanum remains untaxed in local markets.[12] Since the leaves may be consumed as a vegetable and the root tuber as a famine food, it may also increase overall food security of rural households.
Gnetum africanum is most significantly cultivated byrural women farmers, constituting approximately 80% of the overall trade of this crop.[12] WhileGnetum africanum is still largely considered a wild vegetable, if cultivated as a domesticated crop it may save time for women who previously would search for it in the forests.[10]
