Gnetum africanum is an evergreen Climber growing to 12 m (39ft) by m (1ft 4in) at a fast rate. It is hardy to zone (UK) The plant is not self-fertile. Suitable . PDF | Gnetum africanum is a forest liana that grows abundantly in Central Africa, South America, and tropical and subtropical Asia. Its leaves. J Med Food. Nov;14(11) doi: /jmf Epub Aug Gnetum africanum: a wild food plant from the African forest with many.
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Gnetum africanum occurs naturally in the humid forest zones from Nigeria to the Central African Republic and to Angola. Fresh leaves of Gnetum africanum and the very similar Gnetum buchholzianum Engl. They are usually cooked with meat or fish and occasionally consumed as a salad. Gnnetum are shredded into thin strips and are often eaten as part of a mixture in, for example, a groundnut-based stew.
To soften this rather tough vegetable, people often mix it with waterleaf Talinum triangulare Jacq. Shredded leaves can be dried gnetuum preserved for later use.
The seeds are eaten in Cameroon and DR Congo. In Nigeria, eru is used for treatment of piles and high blood pressure and also as medicine against enlarged spleen, sore throat and as a purgative. In the Central Atricanum Republic the leaves are eaten to treat nausea and as an antidote to arrow poison made from Periploca nigrescens Afzel. In Cameroon the leaves are chewed to mitigate the effects of drunkenness and they are taken as an enema against constipation and to ease childbirth. They are also used to treat boils and fungal infections on the fingers.
The supple stem is sometimes used as rope. In trade, consignments of Gnetum africanum and Gnetum buchholzianum are often mixed. Traders will pay more for the thick dark green leaves of the latter, but much variation is also caused by growing conditions. Most eru is consumed locally, but intensive trade has developed from Cameroon and more recently also from Gabon and the Central African Republic to meet the large demand in Nigeria. Most eru from Cameroon, Gabon and the Central African Republic is transported to Idenau, a coastal village in Cameroon, and from there by boat to Nigeria.
Estimates for the annual export of eru leaves both species to Nigeria range between t and t. Another major marketing centre is the Koilo Region in Congo. Dried shredded leaves are exported, mainly from Nigeria to the United States and to a lesser extent from other countries to France and the United Kingdom.
The composition of Gnetum gnteum leaves is probably comparable to Gnetum africanum. The dry matter content of fresh leaves is much higher than for other dark or medium green leaf vegetables. This gives a feeling of firmness during preparation, hence certain consumers consider eru as a substitute for meat.
The leaves of Gnetum africanum are somewhat thinner and paler than the dark green leaves of Gnetum buchholzianum. Consequently, the content of micronutrients in the latter might be somewhat higher. Eru leaves contain C-glycosylflavones, including 2″-xylosylisoswertisin and 2″-glucosylisoswertisin, compounds that are only known from these two species; characteristic of Gnetum africanum is the presence of 2″-O-rhamnoylisoswertisin and apigeninhesperidoside and the absence africznum vitexin and 2″-O-glycosylvitexin.
The leaves of Gnetum africanum can be replaced by those of the other eru species, Gnetum buchholzianumor leaves of the shrub Lasianthera africana P. Gnetum comprises approximately 35 species of small trees, shrubs or most often lianas, found ghetum tropical South and Central America about 7 speciesAfrica 2 species and Asia about 25 species.
They look much like dicotyledonous flowering africanu having opposite leaves with a net venation and cherry-like seedsalthough in fact they are gymnosperms. The 2 African species, which are very similar, have been classified in section Gnetumsubsection Micrognemones.
Gnetum africanum has leaves which are relatively thin and pale afrocanum. Its male catkins have slender internodes of equal width from the base to the tip.
INTERESTING FACTS ABOUT GNETUM AFRICANUM (ERU|OKAZI LEAF)
Gnetum buchholzianum has thick dark green leaves. The male catkins have thick internodes widening towards the terminal part. It was recently proposed that all Gnetum species be transferred to Thoaexcept two Asiatic species, mainly based on seedcoat structure. Both African Gnetum species wfricanum lianas with two different types of stems.
INTERESTING FACTS ABOUT GNETUM AFRICANUM (ERU|OKAZI LEAF)
The orthotropic ones have small, scale-like leaves and rapidly grow vertically, reaching the main branches of a tree where they produce plagiotropic stems with fully developed leaves. The orthotropic stem continues climbing until it reaches the canopy where it branches into several leafy stems. Female plants often show more vigorous growth with stronger stems than male plants.
This is more obvious in Gnetum africanum than in Gnetum buchholzianum. Eru continues to grow during the dry season and new shoots may develop where the stem has been cut or where side shoots have been removed. New shoots are also formed from rhizomes that spread along the forest floor. The distinctly coloured drupe-like seeds are probably dispersed by birds and other animals. Eru can be found in rainforest from sea-level up to m altitude, and prefers an annual rainfall of about mm.
It is usually found with other climbers on middle- and under-storey trees, frequently forming thickets. It can also be found in riverine forest in areas that are otherwise too dry for the species. Gnetum africanum is mostly found at the periphery of primary forest and in secondary forest. Today, it is more common than Gnetum buchholzianumwhich is mainly found in primary forest, especially near openings created by fallen trees.
Experimental plantings for domestication are being made with both species. Nurseries are now concentrating their efforts on Gnetum buchholzianum because it is preferred by traders and is more vigorous.
Moreover, male vines of Gnetum africanum are less appreciated because of their smaller, thinner and paler leaves, and because of their less vigorous growth. For Gnetum buchholzianum there is no need to harvest only female plants. However, the field trials might show that Gnetum buchholzianum is more difficult to cultivate than Gnetum africanum because the former probably requires more shade than the latter.
In experiments in Cameroon, propagation by seed was difficult because the seed is reluctant, germination taking one year or more. It is assumed that seeds need pretreatment, such as passing through the intestines of a bird, fruit bat, squirrel or other animal, before they germinate.
Seed is normally found only in the tree canopy. Seed collection is thus far from easy, a further reason why eru is hardly cultivated.
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Methods of vegetative propagation using leafy stem cuttings have recently been developed. It is recommended that leaf blades of cuttings be trimmed in half. Nursery beds under shade and made of well-decomposed sawdust or fine river sand can be used for propagation.
Ectomycorrhizae assist the roots in absorption of nutrients; the most common species reported is Scleroderma sinnamarense. After about 6 weeks the rooted cuttings are transferred to africanim sleeves, bamboo pots or other containers where they remain for a further 2—3 months.
Field planting, preferably next to a young tree or shrub, takes place at the beginning of the rainy season.
Eru is still mainly collected from wild stands, but farmers often retain it when africxnum fields. If cultivated, gnetkm need to provide support, e. Fences were only found to be successful when there is enough shade, and they are generally too expensive. Fully exposed plants do not grow well; their leaves are thin and pale green, and traders reject them. In experiments, nutrients, especially nitrogen, have shown a positive effect on growth and rate of leaf development.
Mealy bugs are the main pest in the nursery. When eru is grown along dead poles attacked by gnettum, these insects will damage adjacent leaves. Diseases have not been wfricanum to reduce productivity of eru. The current method of harvesting, especially for export trade, is to pull the stems or branches from trees.
This leads to large-scale destruction of natural stands. Occasionally, trees have to be cut to reach leafy stems in the canopy.
This is mainly done during the dry season when the forest is more accessible and when there is little work on the farm. Controlled harvesting, in which only side shoots or parts of stems are collected, is clearly better than destructive harvesting. After controlled harvesting, new shoots may gnehum where a stem has been cut or where side shoots have been removed.
Preliminary observations indicate that 3—4 harvests per year are possible, still allowing for substantial regrowth. More frequent harvesting will result in thin leaves that are considered inferior. The first harvest may take place 6—9 months after planting.
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The total lifespan of eru is estimated at over 10 years. This may double in subsequent years. Leafy stems remain fresh for at least a week. Stems collected from the forest are brought to collecting points from where africanm are either sold in the local market or gnetu.
For this trade, whole leafy stems are packed in large bales. Selection takes place for size and texture of the leaves, and is mainly determined by species. Gnetum buchholzianum is more popular with consumers and more expensive because its leaves are generally thicker than those of Gnetum africanum. Leaves are shredded before consumption or prior to drying.
Eru is gnetuk cultivated at all at present, but there is massive exploitation of the remaining natural stands, which have almost disappeared in Nigeria and are becoming scarce in Cameroon, Gabon and the Central African Republic.
There is an urgent need to collect and preserve the diversity found within the two African Gnetum species, preferably throughout their natural range. Accessions need to be evaluated for their agronomic afrifanum and for their ability to germinate without the need for interventions.
Alternatives to destructive africxnum of eru should be found. Once the new methods of propagation and cultivation have been adopted, there will be scope for development of eru as a new crop, for which there is already a high demand and for which an attractive price could be paid. Diversity found between accessions is considerable, offering scope for improvement of both quality and productivity.
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