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The Botanical Garden, University of Agricultural Sciences, Bangalore

Volume 2 Number 7 - February 1996
K.R. Geetha

The Botanic Garden was planned and developed at the University of Agricultural Sciences (UAS), at Gandhi Krishi Vignana Kendra (GKVK), by Dr R. Narayana, the then Director of Instruction, College of Basic Sciences and Humanities (BS&H), UAS, GKVK, Bangalore, purely for academic interest. His main idea was to introduce indigenous trees, shrubs and woody climbers from various forests of Karnataka and also exotic species. Dr Boraiah and the late Dr G.P. Sathyavathi, the former Heads of the Department of Botany and all the other staff members of the Department of Botany, College of BS&H have put an immense effort into collecting, introducing and maintaining plants in the Botanic Garden.

The Garden has an area of 65 acres and is located at 12.57ºN and 77.35ºE and is at an elevation of about 930 m above sea level. The annual rainfall is about 35", from the south-west. North-east monsoons occur from April to November. The mean maximum temperature for April is 33.4ºC and the mean lowest in December is 15ºC. The soil is red sandy loam on a lateritic bed.

The Garden was started in 1971 with the clearance of scrubby undergrowth, retaining the existing woody plants. The area is divided into ten blocks with paths and walkways and the Garden was inaugurated by planting indigenous and exotic trees such as Ficus religiosa, Azadirachta indica, Cocos nucifera, Areca catechu, Artocarpus heterophyllus, Plumeria alba, Guazuma tomentosa, Dendrocalamus brandisii, Bauhinia purpurea and Michelia chapaca.

The area surrounding the garden was a tropical scrubby forest with Azadirachta indica, Ailanthus excelsa, Anacardium occidentale, Albizzia lebbek, Artabotrys odoratissima, Tamarindus indica, Pongamia pinnata, Hardwickia binata, Cassia siamea, Caesalpinnia coriaria, Terminalia arjuna, Eucalyptus citriodora, E. hybrida, E. malaccensis, Bridelia roxburghiana and Casuarina equisetifolia that were planted by the Forest Department of the State Government before the area was handed over to the University. Even now, they are the conspicous flora and it is intended to thin these out as and when desired plants for the collection are located. In the climatic climax of the area the dominant trees species are Limonia acidissia, Zizyphus mauritiana, Z. xylopyrus, Albizzia amara, Cassia fistula, Bauhinia racemosa, Butea monosperma, Wrightia tinctoria, Santalum album, Streblus asper, Holoptelia integrifolia; the shrub species are Cadaba fruticosa, Capparis spinosa, Flacourtia indica, Erythroxylon monogynum, Cipadessa baccifera, Dodonea viscosa, Cassia auriculata, Randia uliginosa, Canthium parviflorum, Pavetta indica, Jasminun rigidum, Gmelina asiatica, Lantana camara, Breynia retusa, B. rhamnoides; and the woody climbers are Toddalia asiatica, Scutia circumcissa, Zizyphus oenoplia, Pterolobium hexapetalum, Carissa congesta, Ichnocarpus frutescens, Tylophora cordifolia, Gymnema sylvestre, Argyreia speciosa, Lettsonia aggregata and Plecospermum spinosum.

There is an insufficient supply of water for irrigation in the Garden which is the major factor in its development.

The families in the Garden are laid out according to Bentham and Hooker's system. Block A1is earmarked for Medicinal Plants, Block A2 starts with Ranunculaceae and Block A10 has Monocots and Gymnosperms, the total number of species being 600.

Major objectives of the garden are introduction, conservation and multiplication of plants of botanical, horticultural, economic and medicinal value. The Department of Botany also maintains a Herbarium with 3,000 species which is situated in the Botanic Garden. Staff and students of this University and other universities visit the Garden to study plants of various families. Exhibitions of herbarium specimens and rare plants are arranged for visitors.

At present the Botanic Garden is managed by Dr R.V. Ramamohan, Director of Instruction and the Department of Botany is headed by Dr S. Joshi. Dr K.R. Geetha, Assistant Professor of the same department is the Curator of the Garden and Herbarium. There are 5 qardeners.

The Government of India, Ministry of Environment and Forests has supported a project in the garden "Ex situ Conservation and multiplication of rare, threatened, endangered and endemic plants of South India" in 1996-7 to provide basic facilities such as a greenhouse, pond environment and other equipment.

Studies of Pterocarpus santalinus (Red sandal wood)

The Botanic Garden has been working on Pterocarpus santalinus L. (Leguminosae), (Red sandal wood or Red Sanders), a species of southern India listed in Appendix II of CITES. Pterocarpus santalinus is a small to medium sized (25 feet), deciduous tree restricted to parts of Andhra Pradesh, particularly Cuddapah district and neighbouring State. The bark is blackish-brown which exudes a red juice when cut. The flowers are yellowish in short, loose racemes. The sap wood is white and the heart wood scarlet purple with streaks or purplish-black or almost black, dull, with a medium fine texture, very strong, extremely hard, very heavy and contains a red dye santalin (16%) for which it has been valued. The timber is used for house posts, agricultural implements, shaft and bent rims of carts, boxes and dolls. It is exported to Japan where it is used in the manufacture of musical instrument called shamisen.

The wood is considered an astringent, tonic and diaphoretic. A paste of wood is a cooling external application for inflammation and headache. It is used in blood purification, skin diseases, haemophilic disorders, genitourinary and bronchial tract troubles. Leaves are used as fodder.

Germination and propagation studies have been tried with Pterocarpus santalinus. Pre-sowing pod treatments have been tried to improve the seed germination using tap water, hot water, acid-scarification, potassium nitrate, cow-dung slurry and mechanical scarification both in laboratory and field conditions. The effect of different concentrations of Indole Butyric Acid and Napthalene Acetic Acid and their combinations have also been studied on different sizes of cuttings and at different time intervals for taking cuttings.

Germination was improved if the pod was rubbed against rough surfaces, cut with a sharp knife at the proximal end, distal and at both ends. Pods soaked in tap water, hot water and scarified with concentrated sulphuric acid showed no germination under laboratory conditions. Under field conditions, pods soaked in tap water for 412 days, pods sacrified with concentrated sulphuric acid for 4 minutes and sown in soil have recorded 6 to 10 and 5 per cent germination. Pods rubbed against a rough surface recorded less than 2% germination as compared to 0% germination in the control. A startling observation was as many as 90% of the pods were empty of seeds in some samples studied and overall the average percentage of 36% was recorded.

All concentrations (1,000 to 2,000 ppm) of IBA, NAA and their combinations treated to different girths of stem cuttings for 16 hours failed to induce rooting after 30 days of planting under mist conditions during October 1995. The buds present on cuttings started sprouting after 15 days and later some of them started to die after 30 days. This failure to induce rooting by growth regulators may be attributed to seasonal variations and also to the age of the mother tree.

Rauwolfia tetraphylla

Rauwolfia tetraphylla is a small, much branched woody shrub, native of the West Indies, introduced into India and now found as a common weed in the vicinity of port towns along the coasts. It has spread inland and is found as an escape from cultivation in Uttar Pradesh, Bihar, Orissa, Madhya Pradesh, West Bengal, Andhra Pradesh, Mysore, Madras and Kerala States of India.

Two plants of Rauwolfia tetraphylla are in cultivation in the Botanic Garden.

The roots of Rauwolfia tetraphylla are often used as substitute or adulterant of those of Rauwolfia serpentina. The roots are used for the commercial extraction of reserpine. An extract of the plant is mixed with castor oil to form a liniment which is prescribed for some kinds of chronic and refractory skin ailments. A decoction of the bark is employed in some parts of West Indies as an external application for chronic cutaneous diseases and to destroy parasites. The dark juice of the fruit furnishes a black dye.

Examples of endangered plants in cultivation in this garden are Cycas circinalis, Embelia ribes, Garcinia indica, Piper longum, Saraca asoca, Vateria indica.