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The Conservation of the Diversity of Nelumbo (Lotus) at the National Botanical Research Institute, Lucknow (India)

Volume 3 Number 6 - June 2001
Anil Goel, S.C Sharma and A.N Sharga

Lotus (Nelumbo nucifera Gaertner) is a symbol of Indian cultural heritage, deeply associated with Hindu mythology, art and culture and has thus been accorded the status of the National Flower of India. It is one of the most attractive aquatic plant species in India occurring from Kashmir to Kanyakumari exhibiting enormous thermoplasticity and phenotypic diversity with a large number of racial variants with different shapes, sizes and colours of the bloom ranging from white to dark pink and having 16-160 petals. The plants being highly ornamental are exploited for landscaping lakes and ponds. Nelumbo belongs to the monogeneric family Nelumbonaceae. The genus is represented by two species viz. Nelumbo lutea (Willd) Pers. (Yellow lotus) indigenous to North America and N. nucifera. (Kamal in Hindi) from tropical and sub-tropical Asia to Australia and also naturalised in Hawaii.

Ex Situ Conservation

In consideration of the significance of this aquatic plant species, the National Botanical Research Institute under the biodiversity conservation programme maintains the national collection comprising of 60 species/races of Nelumbo. Out of which 35 species/races are indigenous and collected from 8 States {Bihar, Karnataka, Madhya Pradesh, Maharastra, Orissa, Tamil Nadu, Uttar Pradesh and West Bengal) and 3 Union territories of India (Chandigarh, New Delhi and Pondichery) as well as 25 exotic races introduced from Australia, Brazil, Germany, Thailand, U.K. and U.S.A. Nelumbo lutea was introduced into India for the first time from the Missouri Botanical Gardens St Louis, U.S.A. in 1993 and has been performing well under Lucknow conditions. The NBRI collected a 160- petalled pink coloured race of lotus from the Midnapur district of West Bengal which is unique and very attractive. This lotus has been named as N. nucifera ' Krishna'.

Propagation

Lotus is multiplied by seed and vegetatively by the division of rhizomes. The seed remains viable for a long time and can be stored at room temperature. Excavated seeds from South Manchuria remained viable and germinated even after five hundred years. For quick and better germination, the seeds are scarified by rubbing them gently on the sand paper at both the ends and immersing in water. Scarified seeds germinate after 3-4 days whereas normal seeds take 10-15 days to germinate. The rhizomes of the preceding years crop are used for propagation. Each segment of the rhizome should contain at least three nodes with new sprouts and are planted horizontally at a 10 cm depth during the rainy season.

Culture

In nature, lotus is usually found growing in lakes and ponds and migrates from one place to another during its life span. The old plant degenerates and a new one becomes established from a floating rhizome the following season depending upon the available space and water.

The NBRI has succeeded in growing lotus successfully under, artificial conditions in cement concrete tanks by having a clay soil stratum up to 45 cm thick at the bottom of the tank and maintaining the water level from 1-1.5 metres. The clay soil is enriched by incorporating well-decomposed cattle dung manure @ 5 kg/m², neem cake @ 100 gm/m², di-ammonium phosphate {DAP) @ 25 gm/m², single superphosphate @ 50 gm/m² and muriate of potash @ 25 gm/m² as a basal dose at least 15 days prior to the planting (February - March). Planting takes place during March - April with a 4 m² for each seedling.

Seedlings are transplanted at the 2-3 leaf stage at the bottom of the pond. After planting water is added to get the plants established. Subsequently, the level of water is raised gradually depending upon the growth of the plants so that the leaves remain floating on the water surface rather than getting submerged which may cause decay resulting in plant casualties.

Lotus requires to be replanted for display tanks by thinning the rhizomes in the month of February and enriching the soil stratum by incorporating manures and fertilizers at recommended levels for ensuring proper growth. It is important to maintain the required level of water throughout its life cycle for best performance.

Flowering and fruiting in lotus takes place during March to October. The intensity of flowering and fruiting decreases during extreme hot summer and rainy days. A moderate climate has been found to be the most suitable for the optimum growth and profuse flowering. Phenological studies have revealed that there is a thermo-regulatory mechanism in lotus plants which maintain a steady environment inside the flowers to facilitate successful pollination by humming bees.

Insects, Pests And Diseases

Aphids cause considerable harm to lotus plants by sucking sap from the tender growing leaves and flower buds. The aphids may be controlled by spraying the plants with malathion @ 0.2% using an appropriate wetting agent and @ 0.1% preferably in the morning hours when required. Beetles also damage the leaves by feeding on them and should be dislodged by a jet of water or destroyed by hand picking.

Nutraceutical, Medicinal and Commercial Importance

Lotus has many other uses besides its ornamental value. Being sacred, the flowers are offered to gods and goddesses in temples during religious festivals. The buds are used as cut flowers for making floral arrangements and the dried torus is used in floral decorations. The leaves are used as plates for serving food, during festivities in rural areas. Various parts of the lotus plant are edible and are said to rejuvenate the human body. Young leaves, petioles and flowers are eaten raw or cooked as vegetables. The fresh rhizomes are also relished as a vegetable and for making pickles. The unripe seeds embedded in the receptacle are edible and nutritious - the seeds are eaten after removing the outer covering which is bitter in taste. The seeds, which are sweet and delicious, are eaten raw, roasted, boiled or made into candy. Sometimes flour is prepared by grinding them.

Medicinally, it has cooling, astringent, demulcent properties and is used in Ayurvedic formulations for curing dysentery diarrhoea, cough and cold. The flowers are used as a cardiotonic and in liver, urinary and venereal disorders. The seeds are valued in conception and blood disorders. The powder made of leaves and rhizomes is prescribed for the treatment of piles. The fragrant flowers yield very high quality honey and perfume which is used for the several religious and medicinal purposes.

In some places, lotus is grown commercially 4-5 kg of seed is required for one acre of pond area. The flowers can be sold and a good crop may yield 12-15 quintals (100 kg) rhizome per acre which is harvested in October - November when the plants are dormant. The rhizomes are sold in the vegetable market @ Rs. 16-20 per kg. The lotus seeds fetch a price of Rs. 50-60 per kg.

Pollution Management

Lotus plants can tolerate acidic and alkaline water in a pond. During the survey, it was observed that lotus was growing luxuriantly in Samaspur lake in Raebareilly diatrict of Uttar Pradesh which has an alkaline pH of 9.0-9.3. Investigations have also revealed that lotus can absorb heavy metals and may be recommended for plantation in the ponds used for discharging the industrial effluents for water purification in a most natural manner. Further, the lotus can be planted in large tubs/pots and placed in swimming pools which provides an attractive feature and purifies the water naturally without the use of harmful chlorides.

Conservation

The Nelumbo collection of 25 exotic and 35 indigenous races at NBRI has aroused considerable interest in the visitors who have become fascinated by the phenotypic diversity (shape, size and colour of flowers ranging from white to dark pink and the attractive blooms of the newly-introduced Yellow lotus (Nelumbo lutea). Information about the conservation of Nelumbo has been disseminated through the publication of popular articles, research papers, press and electronic media.

People have developed taste in greening their surroundings by growing plants near dwellings. There is a great demand for lotus plants for medicinal, religious and aesthetic purposes. Their keen interest in the cultivation of aquatic plants particularly the lotus and waterlilies is increasing rapidly. The commercial cultivation of lotus can be a highly profitable floriculture industry. NBRI has so far provided living plant material of lotus to over 200 parties including plant growers, government and non-government organisations and connoisseurs so that it can be safely conserved, admired and sustainably used for posterity.

Conservation of Nelumbo nucifera and its sustainable use can help keep this marvellous and heavenly species alive, improve the economic condition of poor rural people and protect water sites

Anil Goel, S.C. Sharma and A.N. Sharga
Botanic Garden
National Botanical Research Institute
Rana Pratap Marg
P.B. No 436
Lucknow - 226 001
India
Tel: +91 0522 271031/5
Fax: +91 0522 205836/205839
E-Mail: nbri@Lw1.vsnl.net.in

 
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