Nelumbo nucifera (PROSEA)

Plant Resources of South-East Asia Introduction

List of species

Nelumbo nucifera Gaertner

Protologue: Fruct. sem. pl. 1: 73 (1788).

Family: Nymphaeaceae

Chromosome number: 2n= 16

Synonyms

• Nymphaea nelumbo L. (1753),
• Nelumbium speciosum Willd. (1799),
• N. nelumbo (L.) Druce (1913).

Vernacular names

• Lotus, sacred lotus, Indian lotus (En). Lotus sacré (Fr)
• Indonesia: terate, seroja, padma
• Malaysia: seroja, padema, teratai
• Philippines: baino (Tagalog), sukan (Bikol), sukaw (Ilokano)
• Cambodia: chhu:k
• Laos: bwà
• Thailand: bua-luang (general), ubon (central), sattabut (central)
• Vietnam: sen, hoa sen.

Origin and geographic distribution

N. nucifera originates from continental Asia (possibly India), but is now widely distributed (wild or cultivated) from north-eastern Africa to north-eastern Australia, including South-East Asia, China and Japan. For at least 6000 years it has been associated with Indian culture and religion as a sacred flower. It is also occasionally cultivated as an ornamental in Europe, Africa and America.

Uses

The starchy rhizomes are eaten raw or cooked and are marketed fresh, dried, canned, as flour, pickled or preserved as sweetmeats. They are in demand by Chinese the world over. Unripe seeds are eaten fresh as nuts. Ripe seeds are eaten raw, boiled or roasted, usually with the bitter embryo removed. Before being sold in dried form, the seed coat and embryo are removed. The young rhizome shoots and unexpanded leaves are eaten boiled as a vegetable, and the very young leaves can be eaten raw.

In traditional medicine, lotus has many applications. The Chinese use the rhizomes to treat diarrhoea and dysentery, while the Cambodians use them to make a tea for menorrhagia. Embryos are used in China for reducing fever, for treating cholera, haemoptysis, spermatorrhoea and as a tonic; in Malaysia they are used as an application against fever and are taken as tea. In Indonesia, the petals are given against diarrhoea and vomiting; in Malaysia they are pounded and administered to treat syphilis; the Chinese use them in cosmetic applications; in India they are used against fevers and dysentery, in Cambodia and the Philippines against dysentery. The Chinese apply the stamens as astringent, diuretic and in cosmetics; in India they are applied as astringent and for cooling, and in Indo-China for flavouring tea. In Indonesia and India, the slimy juice from the petioles and peduncles is used to treat diarrhoea. The leaves are convenient wrappers, especially for food to be cooked. In India, the fibres in the petioles are made into wicks for religious lamps and a perfume is extracted from the flowers. Besides its many uses, N. nucifera is perhaps most important as an ornamental for the beauty of its flowers and fruits, the latter also in dried form. In India, lotus is the "national flower". It is the symbol of divineness, purity, beauty, kind-heartedness, fragrance, coolness, fertility, prosperity and is given due prominence by poets, artists, sculptors, architects, and craftsmen.

Production and international trade

No statistics are available but lotus is most important in India, China and Japan. In South-East Asia, lotus is grown only for the local market, and seeds and rhizomes are on sale throughout the year. Dried lotus seeds are produced in southern China and exported to many parts of the world where Chinese communities have settled. The seeds are easily available at Chinese sundry shops and medicinal halls in South-East Asia. The fresh, dried or processed rhizomes are also exported by China. Some produce is obtained from natural stands, but most is from cultivation.

Properties

Per 100 g edible portion, fresh rhizomes contain approximately: water 80-85 g, protein 2-3 g, fat 0.1-0.2 g, carbohydrates 10-12 g (starch 9-10 g, sugar 1-2 g), fibre 0.5-1 g, ash 1-2 g, Ca 60 mg, thiamine 0.2 mg, riboflavin 0.06 mg, niacin 2 mg, ascorbic acid 15 mg. The starch grains are large, elongated, 65-100μm long. Dried seeds contain per 100 g edible portion: water 12 g, protein 18 g, fat 2 g, carbohydrates (starch and sugar) 62 g. The embryos contain an alkaloid called nelumbine, which is also found in young leaves and petioles. Other alkaloids isolated are nuciferine, roemerine and nornuciferine.

Description

• A large, perennial, glaucous, glabrous, aquatic herb, 1.2-2.5 m tall, containing milky latex, rooting in the substrate (usually mud). Rhizomes creeping, jointed, up to 10 m long, 6-9 cm in diameter, interjoints ellipsoidal, 10-30 cm long, white to light brown, fleshy, mucilaginous and slightly fibrous.
• Leaves peltate, arising from the joints, one per joint; petiole terete, up to 2.5 m long, covered with short fleshy prickles, inside with numerous air canals; blade depressed orbicular or shallowly cup-shaped, up to 90 cm or more in diameter, entire, glaucous above, purplish beneath, raised above the water.
• Flowers solitary, axillary, projecting above the water higher or as high as the leaves, erect or nodding, 15-25 cm in diameter, fragrant, pink with a white base, rarely entirely white; pedicel erect, terete, up to 2 m long or longer, prickly like the petiole; sepals 2-5, up to 2.5 cm × 2 cm, falling off before anthesis; petals about 20, unequal, obovate, up to 7-15 cm × 3-7 cm, inserted at the base of the receptacle, the outer ones smallest, the intermediate ones largest, the innermost ones medium-sized; stamens numerous, inserted immediately above the corolla, filaments linear, up to 2.5 cm long, anthers yellow; receptacle obconical with a flat apex, 2-4 cm × 3-4 cm, spongy, yellow at anthesis, turning green to finally black-brown and 6-11 cm in diameter; ovaries 10-30, wide apart, sunken in apex of receptacle, free, uniovulate; style short, stigma thickened.
• Fruit an aggregate of indehiscent nutlets; nutlets 10-30 per aggregate fruit, ovoid-oblongoid, 1-2.5 cm × 1-1.5 cm, black-brown.
• Seed with one bifid cotyledon and endosperm enveloping the embryo as a thin membrane.

Growth and development

Plants raised from seed take longer to flower than those grown from rhizome parts. Under ideal conditions, rhizomes can grow 6-9 m in a season. The plant requires 5-6 years to establish well and to reach the stage of full bloom.

Other botanical information

Lotus is often miscalled and confused with the Egyptian sacred lotus, Nymphaea lotus L. Nelumbo nucifera can easily be distinguished from Nymphaea L. by its round peltate leaves mostly reaching high above the water and by its distinct uniovulate carpels embedded in the receptacle. The genus Nelumbo Adans. comprises only 2 species and is sometimes separated from the Nymphaeaceae as a distinct plant family Nelumbonaceae .

The second species is the American lotus, N. lutea (Willd.) Pers., occurring in eastern North America, and having smaller leaves and yellow flowers.

Based on flower colour (pink, red or white), flower size (single or double flowers), fragrance, and leaf colour (green or variegated), many cultivars of N. nucifera are distinguished. Well-known cultivars include:

• "Alba": flowers white, large and fragrant.

• "Alba Plena" or "Shiroman": a Japanese cultivar with double large flowers, cream with a green centre, turning pure white on the third day, very fragrant.

• "Chawan Basu": a semi-dwarf cultivar with pink flowers that are white-edged.

• "Pekinensis Rubra": flowers carmine-pink.

• "Red Lotus": flowers deep red and large.

Ecology

The natural habitat for lotus is freshwater bodies in tropical and subtropical Asia. Lotus grows in old mining pools, natural or man-made lakes, canals and ponds. Because the rhizomes lie deep in the mud under water, they are beyond the reach of frost that would kill them. Therefore, lotus is widely distributed in Asia even in regions not free from frost. It occurs from sea-level up to 1800 m altitude.

Propagation and planting

Pieces of rhizomes are usually used as planting material and planted with the buds just above the mud under about 1 m of water. Lotus seed will also easily produce plants, but it takes more time to produce rhizomes of marketable size. From seed, seedlings are raised in nursery beds and planted out after about 2 months. Lotus fruits (seeds) are said to remain viable for more than a century. The fruit wall forms a hard cover protecting the seed. Fruits which have been kept for a long time need to be scarified to stimulate germination of the seed. About 45 kg of rhizome pieces or 10 kg of seed are required to plant one ha.

Husbandry

Water weeds like Eichhornia crassipes (Mart.) Solms and Typha spp. compete with lotus plants and must be removed. Application of organic fertilizer stimulates growth.

Diseases and pests

Under natural conditions, lotus is a hardy plant with few serious diseases and pests. Under cultivation, however, two common diseases are leaf spot (caused by Cercospora sp. and Ovularia sp.) and rhizome rot (caused by Bacillus nelumbii and Fusarium sp.). Considerable leaf damage can be caused by aphids and beetles. In some areas, the rice root worm ( Donacia provostii ) causes damage. Application of fungicides and insecticides is often not possible because of the danger of killing fish as well.

Harvesting

In non-seasonal climates, the flowers, fruits and rhizomes are harvested throughout the year. In seasonal climates, harvesting follows the rainy season. When cultivated in ponds, the rhizomes are dug up by hand after the ponds are drained. Flower buds, picked 2-3 days before opening, withstand long-distance transportation quite well, and are popular among Buddhist and Hindu communities. Lotus fruits are collected when ripe.

Yield

In a survey of 12 plots of lotus in the Kinta Valley in the state of Perak, Malaysia, the yield of rhizomes varied from 3.1-8.2 t/ha per season. In Punjab, India, about 62 ha of lotus were reported to produce 3.8-4.7 t of rhizomes per ha.

Handling after harvest

Rhizomes are sold fresh in the market or made into preserved sweetmeats. Fresh rhizomes have a shelf life of about 2 weeks. Rhizomes are also dried and made into flour. The wall and embryo of ripe fruits (seeds) are removed before sun-drying. Seed is packed and sold dried or made into flour.

Genetic resources

There are no known germplasm collections of N. nucifera . The species does not seem to be in danger of genetic erosion.

Breeding

Lotus plants for the production of rhizomes are mainly of the pink-flowered type, and rarely of the white-flowered type. Systematic plant breeding concentrating on rhizome number and size may improve production.

Prospects

Lotus is one of the few crops that can be cultivated in water bodies of 2 m or more deep, producing food rich in carbohydrates. Others such as rice, Chinese water chestnut (Eleocharis dulcis (Burm.f.) Trinius ex Henschel), water chestnut (Trapa natans L.) and arrowroot (Maranta arundinacea L.), all need shallower water. Lotus can be grown in old mining pools and natural water bodies which would otherwise have no use.

Literature

• Herklots, G.A.C., 1972. Vegetables in South-East Asia. George Allen & Unwin, London, United Kingdom. pp. 492-494.
• Kay, D.E., 1973. Crop and product digest No 2. Root crops. Tropical Products Institute, London, United Kingdom. pp. 89-92.
• Swarup, V., 1989. Lotus. In: Bose, T.K. & Yadar, L.P. (Editors): Commercial flowers. Naya Prokash, Calcutta, India. pp. 7-13.
• Swindells, P., 1983. Waterlilies. Croom Helm, London, United Kingdom.

Authors

H.C. Ong