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Talinum triangulare (Jacq.) Willd.

Protologue
Sp. pl. 2: 862 (1799).
Family
Portulacaceae
Chromosome number
2n = 24, 48, 72
Synonyms
Talinum fruticosum auct. non (L.) Juss.
Vernacular names
Waterleaf, talinum, Ceylon spinach (En). Grassé, pourpier tropical (Fr). Beldroega grauda, lustrosa grande (Po).
Origin and geographic distribution
Waterleaf is a cosmopolitan weed common throughout the humid tropics. It has been recorded for several countries in West and Central Africa. It is claimed to have a South American origin, but an African origin may also be possible, as several Talinum species including the closely related Talinum portulacifolium (Forssk.) Schweinf. occur in Africa. Waterleaf is eaten as a vegetable throughout the tropics including many countries in West and Central Africa; it is cultivated in Nigeria and Cameroon.
Uses
The leaves are used in the preparation of slightly slimy soups and stews to complement the starchy main dish. In southern Nigeria, where it is called ‘gbure’, it is commonly mixed in soups with Jew’s mallow (Corchorus olitorius L.). Pepper and some dry fish and meat are often added to improve the taste and nutritional qualities of the sauce. Waterleaf sauce may also be a mixture of tomatoes, onion and waterleaf to which palm oil and salt are added. In Cameroon, where it is called ‘bolki’ or ‘belok-sup’, waterleaf combined with eru (Gnetum leaves) and fufu (starchy dish) is considered a delicacy; the tender shoots of waterleaf soften the tough leaves of eru. In Nigeria waterleaf is collected from the wild during the dry season when other more popular vegetables are scarce and expensive. The collection of waterleaf from the wild is a good source of income for poor farmers. The leaves are also eaten raw in salads. Waterleaf is used as a colouring agent in okra soup.
In Cameroon, waterleaf is used as a treatment for measles, whereas in Assam (India), it is used to treat diabetes. In Indonesia a tonic is made from the fleshy root. In experiments waterleaf performed well as a fodder for raising giant snails.
Production and international trade
Waterleaf was long considered a vegetable for the poor and was thus not highly valued. Since the increased popularity of eru (Gnetum leaves) in Cameroon and eastern Nigeria from around 1990 onwards, the demand for waterleaf has steadily risen. It is now a common product on local markets, but no data on production and trade are available.
Properties
The leaves contain per 100 g edible portion: water 90.8 g, energy 105 kJ (25 kcal), protein 2.4 g, fat 0.4 g, carbohydrate 4.4 g, fibre 1.0 g, Ca 121 mg, P 67 mg, Fe 5.0 mg, thiamin 0.08 mg, riboflavin 0.18 mg, niacin 0.3 mg, ascorbic acid 31 mg (Leung, W.-T.W., Busson, F. & Jardin, C., 1968). The vitamin A content is comparable to other medium green leafy vegetables, about 900 μg.
Waterleaf is a mucilaginous vegetable with high oxalate content. The presence of oxalate is a drawback since more than 90% of it is present in soluble form and can induce kidney stones if taken in excess. Blanching or cooking removes nearly half of the soluble oxalate. Waterleaf also contains hydrocyanic acid, which is a further reason why this vegetable should be consumed in small quantities only and why it is not recommended for livestock. Caution should be exercised in the use of this vegetable in infant foods, the more so since it contains nitrates and nitrites, which are not removed by cooking. Waterleaf is rich in saponins.
Adulterations and substitutes
In most dishes waterleaf can be replaced by Basella alba L. or any other watery slimy leafy vegetable.
Description
Erect, glabrous perennial herb up to 80(–100) cm tall, usually strongly branched; roots swollen and fleshy; stem succulent, obtuse-angular to terete. Leaves alternate, simple, almost sessile, succulent; stipules absent; blade obovate to spatulate, 3–15 cm × 1–6 cm, base long-tapering, apex rounded to notched, mucronate, entire, venation pinnate, indistinct. Inflorescence a terminal cyme on a triangular stalk up to 12 cm long. Flowers bisexual, regular; pedicel c. 1 cm long, recurving in fruit; sepals 2, free, with 3 prominent veins; petals 5, free, obovate, up to 1 cm long, pink; stamens numerous; ovary superior, 1-celled, style slender, with 3-branched stigma exceeding stamens. Fruit a globose to ellipsoid capsule 4–7 mm long, 3-valved, elastically dehiscent, many-seeded. Seeds compressed globose-reniform, c. 1 mm long, tuberculate, shining black.
Other botanical information
Talinum comprises about 40 species, most of them found in Mexico and southern United States, and 7 species in tropical Africa. Talinum triangulare is sometimes confused with Talinum portulacifolium, but the latter differs by its paniculate inflorescence with terete axis, sepals not prominently veined and smooth seeds.
Growth and development
The onset of flowering does not appear to affect leaf or shoot production. Plants take 40–75 days to flower from stem planting, and at flowering they have 4–9 branches and 25–90 leaves. Waterleaf is recorded as being self-pollinated with a limited degree of out-crossing. Fruiting takes 75–80 days from stem planting. Under natural conditions, plants will live for 4–6 months. Waterleaf is relatively tolerant to drought. Exposed to drought it adopts a crassulacean acid metabolism (CAM), resulting in an effective use of available moisture, carbon dioxide assimilation continuing during the night and increased growth.
Ecology
Waterleaf grows best under humid conditions at temperatures of about 30°C. Growth is very fast during the rainy season but will slow down considerably during the dry season. It grows well under shade and in cloudy weather. It can grow in fully exposed localities, but there plants remain smaller. Growth is most profuse when the water content of the soil is close to field capacity. High temperatures (>35°C) and drought negatively affect the number of leaves, leaf area, stem size, and number of branches.
Management
After planting, watering is required daily during the first week, and three times per week when the plants have covered the soil completely. Waterleaf needs much nitrogen; yellowing of leaves indicates lack of nitrogen. It may be fertilized with household waste, dung or mineral fertilizer. Nitrogen may be applied at intervals of 2–3 weeks to stimulate leaf development.
Waterleaf can be a weed in cultivated or disturbed land, including roadsides and near homesteads, but few farmers worry about it since its roots are shallow and the plant is easy to remove.
Propagation and planting
Waterleaf can be sown, planted or collected from the wild. Commercially, it is mostly grown through cuttings 10–15 cm long. It is advisable to remove the lowest pair of leaves before planting. In Cameroon and Nigeria, the first planting usually takes place in November. Waterleaf may also be propagated by seed. Seeds are tiny (the 1000-seed weight is about 0.25 g) and can only be collected from fruits which have turned yellow. However, collection of seeds from mature fruits is difficult as they shatter when touched. Green fruits will not yield viable seeds, but nearly mature fruits, that do not yet readily dehisce, yield seed that has an acceptable germination rate after proper drying. The seeds are thoroughly mixed with fine dry sand and the mixture is broadcast in a well-prepared nursery bed. Germination takes place after about 5 days and subsequent growth is very rapid if adequate water is supplied. Seedlings can be transplanted when 3 weeks old. Waterleaf is frequently intercropped with other vegetables. Alternatively, it can be grown as a sole crop at a spacing of about 15 cm × 15 cm. A close spacing reduces competition from weeds and is possible because pressure from diseases is limited. In fertile soils or with adequate fertilizer spacing may be increased to 25 cm × 25 cm.
Diseases and pests
Waterleaf is one of the few vegetables that are hardly affected by pests or diseases. The most common diseases are white leaf spot (Pleospora spp.) and leaf mosaic caused by an unknown virus. A so-far unidentified blight causes dark-green spots on the underside of the leaves. The spots later turn brown or reddish on the upper side of the leaves and eventually become black, rendering the shoots unsaleable. There is no known treatment other than eliminating affected plants at an early stage. Waterleaf is a host of root-knot nematodes (Meloidogyne spp.).
Harvesting
It takes only 3 weeks from planting until the first harvest can take place. Thereafter, shoots can be harvested at 1–2 week intervals for a period of two months. Leaf size decreases with increasing plant age and number of harvests. The first 1–3 harvests provide the best leaf quality for marketing. On average, farmers can harvest 4 times from a plant before its growth starts to decline. The best way to harvest a crop is by cutting the stem just above ground level. This allows faster regeneration than harvesting only the upper portion and side shoots. When the first harvest is delayed and the lower parts of the stem are becoming brown and have dropped their leaves, it is still advisable to cut just above the ground in order to obtain a better quality for the next harvest. A crop planted by cuttings is best harvested by cutting the new side shoots. A few weeks after the start of the rainy season, wild plants will be offered at the market at highly competitive prices and at this stage cultivation is no longer feasible, especially when labour has to be paid for. A rain-fed crop can remain in the field for 60–180 days.
Yield
The yield range is 10–60 t/ha.
Handling after harvest
Waterleaf is highly perishable and the shoots may start withering only a few hours after being harvested. This is not a problem when people wish to dry the product, but it is no longer suitable as a fresh marketable vegetable. It is possible to store the shoots in a plastic bag in a refrigerator for several days.
Genetic resources
No collections of germplasm of Talinum triangulare are known to be maintained. There seems to be no risk of genetic erosion because it is widespread and has a weedy habit.
Breeding
Accessions collected in Nigeria and Cameroon showed very limited diversity and it was not found worthwhile to select lines that could be developed into distinct cultivars. In Nigeria the green type is most common, but occasionally plants with varying degrees of purple colouration in leaves and stems have been found in the south-eastern part of the country, where waterleaf is often cultivated.
Prospects
Waterleaf is a productive, nutritious and easy-to-grow vegetable. With expanding commercial production, waterleaf could become a source of income for a limited number of farmers and traders. Introducing waterleaf in new areas is not recommended because it can easily become a weed.
Major references
• Akachuchu, C.O. & Fawusi, M.O.A., 1995. Growth characteristics, yield and nutritive value of waterleaf, Talinum triangulare (Jacq.) Willd. in a semi-wild environment. Discovery and Innovation 7(2): 163–172.
• Burkill, H.M., 1997. The useful plants of West Tropical Africa. 2nd Edition. Volume 4, Families M–R. Royal Botanic Gardens, Kew, United Kingdom. 969 pp.
• Chibili, E.O., 1999. A comparative study of some developmental characteristics in Talinum fructicosum (L.) Juss. accessions from stem cuttings in Dschang (Cameroon). Mémoire de Maîtrise. Université de Dschang, Cameroon. 37 pp.
• Nyananyo, B.L.O. & Olowokudejo, J.D., 1986. Taxonomic studies in the genus Talinum in Nigeria. Willdenowia 15: 455–463.
• Rifai, M.A., 1993. Talinum triangulare (Jacq.) Willd. In: Siemonsma, J.S. & Kasem Piluek (Editors). Plant Resources of South-East Asia No 8. Vegetables. Pudoc Scientific Publishers, Wageningen, Netherlands. pp. 268–269.
• Schippers, R.R., 2000. African indigenous vegetables. An overview of the cultivated species. Natural Resources Institute/ACP-EU Technical Centre for Agricultural and Rural Cooperation, Chatham, United Kingdom. 214 pp.
• Stevels, J.M.C., 1990. Légumes traditionnels du Cameroun: une étude agrobotanique. Wageningen Agricultural University Papers No 90-1. Wageningen University, Wageningen, Netherlands. 262 pp.
• van Epenhuijsen, C.W., 1974. Growing native vegetables in Nigeria. FAO, Rome, Italy. 113 pp.
Other references
• Baquar, S.R., 1986. Cytotaxonomic studies of the family Portulacaceae from Nigeria. Kromosomo (Tokyo) 2(41): 1255–1262.
• Ebenso, I.E. & Okafor, N.M., 2002. Alternative diets for growing Archachatina marginata snails in south-eastern Nigeria. Tropical Science 42(3): 144–145.
• Herrera, T., 1999. Effects of photoperiod and drought on the induction of crassulacean acid metabolism and the reproduction of plants of Talinum triangulare. Canadian Journal of Botany 77(3): 404–409.
• Leung, W.-T.W., Busson, F. & Jardin, C., 1968. Food composition table for use in Africa. FAO, Rome, Italy. 306 pp.
• Oomen, H.A.P.C., 1971. The significance of leafy vegetables for tropical diets. Food Foundation/IITA/IRAT Seminar on Vegetable Crop Research, Ibadan, Nigeria.
• Phillips, S.M., 2002. Portulacaceae. In: Beentje, H.J. (Editor). Flora of Tropical East Africa. A.A. Balkema, Rotterdam, Netherlands. 40 pp.
• Siakia, A. & Shadeque, A., 1994. Ceylon spinach, a leafy vegetable growing wild in Assam. Indian Horticulture 784: 10–11.
• Simo, C., 1999. Caractéristiques morphologiques et usages du grassé: Talinum fructicosum (L.) Juss. (Portulacaceae) au Cameroun. Mémoire de Maîtrise. Université de Dschang, Cameroon. 31 pp.
• Tindall, H.D., 1983. Vegetables in the tropics. Macmillan Press, London, United Kingdom. 533 pp.
• Tölken, H.R., 1969. The genus Talinum in southern Africa. Bothalia 10(1): 19–28.
Sources of illustration
• Rifai, M.A., 1993. Talinum triangulare (Jacq.) Willd. In: Siemonsma, J.S. & Kasem Piluek (Editors). Plant Resources of South-East Asia No 8. Vegetables. Pudoc Scientific Publishers, Wageningen, Netherlands. pp. 268–269.
Author(s)
D.A. Fontem
Faculty of Agriculture, University of Dschang, Box 208, Dschang, Cameroon
R.R. Schippers
De Boeier 7, 3742 GD Baarn, Netherlands


Editors
G.J.H. Grubben
Prins Hendriklaan 24, 1401 AT Bussum, Netherlands
O.A. Denton
National Horticultural Research Institute, P.M.B. 5432, Idi-Ishin, Ibadan, Nigeria
Associate Editors
C.-M. Messiaen
Bat. B 3, Résidence La Guirlande, 75, rue de Fontcarrade, 34070 Montpellier, France
R.R. Schippers
De Boeier 7, 3742 GD Baarn, Netherlands
General editors
R.H.M.J. Lemmens
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands
L.P.A. Oyen
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands
Illustrator
PROSEA
PROSEA Network Office, Herbarium Bogoriense, P.O. Box 234, Bogor 16122, Indonesia
Photo Editor
E. Boer
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands

Correct citation of this article:
Fontem, D.A. & Schippers, R.R., 2004. Talinum triangulare (Jacq.) Willd. In: Grubben, G.J.H. & Denton, O.A. (Editors). PROTA 2: Vegetables/Légumes. [CD-Rom]. PROTA, Wageningen, Netherlands.
Distribution Map wild and planted


1, flowering and fruiting shoot; 2, flower in longitudinal section; 3, pistil (ovary in longitudinal section); 4, fruit; 5, seed.
Source: PROSEA



flowering plants


field


habit with a few flowers


ripe capsules shatter to disperse their seeds


flowering plant