Economic botany deals with the importance of botany.
The primary needs of human beings are food, shelter and clothing; and all the three are supplied by plants. Different plants yield food, fibres, oil, wood, vegetables, rubber, drugs, fruits, latex, spices, beverages, gums, tannins, dyes, etc. Economically important plants can be classified into the following types—
Medicinal plants : Medicinal plants or drug plants are studied under pharmacognosy. All over the world there are several thousand drug yielding plants. Most of the drugs are obtained from wild plants. The medicinal value of most drug plants is due to the chemicals in the plant tissue which produce a specific physiological effect on the human body.
Different drugs are obtained from different parts of plants.
These are—
(a) Drugs obtained from the roots : e.g. Aconite, Belladona or Sag angur (Atropa belladona-Solanaceae), Colocinth (Citrullus colocynthes), Sarsaperilla (Hemidesmus indicus), Serpentine or Sarpgandha (Rauwolfia surpentina-Apocynaceae), Ashwagandha (Withania somnifera).
(b) Drugs obtained from underground stems : e.g. Turmeric or Haldi (Curcuma iona-Zingiberaceae), Mango zinger (Curcuma amada), Garlic (Allium sativum), Onion (Allium sepa).
(c) Drugs obtained from barbs : e.g. Mountain ebony (Bauhinia variegata) Cinnamon or Dalchini (Cinnamomum zeylanicum-Lauraceae), Quinine (Cinchona officinalis).
(d) Drugs obtained from stems and woods : e.g. Ephedrine (Ephedra gerardiana-Gnetaceae), White sandal wood (Santalum album-Santalaceae), Catechu or Kattha (Acacia catechu-Mimosaceae).
(e) Drugs obtained from leaves: e.g. Vasaka (Adhatoda vasica), Indian Aloe (Aloe barbedensis), Life plant (Bryophylum pinnatum), Holy Basil or Tulsi (Ocimumsanctum-Labiatae), Betel Pepper (Piner betal-Piperaceae).
(f) Drugs obtained from flowers : e.g. Saffron or Kesher (Crocus sative-Iridaceae), Violet (Viola odorata), Iron wood (Mesua ferrea).
(g) Drugs obtained from fruits : e.g. Coriander or Dhania (Coriandrum sativum-Umbelliferae), Cumin or Zira (Cuminum cyminum-Umbelliferae), Emblic or Amla (Emblica officinalis-Euphorbiaceae), Opium or Afeem (Papaver somniferum-Papaveraceae).
(h) Drugs obtained from seeds : e.g. Croton (Croton tiglium), Carrot (Daucus carrota), Pongam (Pongamia pinnata).
(i) Drugs obtained from all parts of plants : e.g. Blood wort (Achillea millefolium), Neem tree (Azadirachta indica), Spiny bamboo (Bamboosa bambos), Black nightshade (Solanum nigrum), Indian Solanum (Solanum xanthocarpum).
Spicies
Spicies have added many advancements in the culture and civilization. Although their nutritive value is less but they give a good flavour and aroma to food.They stimulate appetite and usually contain some essential oil. They give a taste to the food. Some important spices are—
1. Ginger or Adrak (Zingiber officinale)—Zingiberaceae
2. Asafoetida or Heeng (Ferula asafoetida)—Umbelliferae
3. Clove or Laung (Syzygium aromaticum)—Myrtaceae
4. Black pepper or Kali mirch (Piper nigrum)—Piperaceae
5. Fennel or Saunf (Foeniculum vulgare)—Umbelliferae
6. Cardamom or Elaichi (Elettaria cardamomum)—Zingiberaceae
7. Peppermint (Mentha pipe-rita)—Labiatae
8. Mustard (Brassica com-pestris)—Crusiferae.
9. Dhaniya.
10. Zeera.
Fibres
Fibre yielding plants have played an important role in our upliftment. By now more than two thousand kinds of fibres have been obtained from various plants. However commercial fibre yielding plants are few in number. Fibres are generally long cells with thick walls, correspondingly small cavities and usually have pointed ends. They form the skeleton of the plant body. Economically they may be divided into following groups—
(a) Textile fibres : e.g. Cotton (sps. of Gossypium), Flex (Linumusitatissimum), Jute (Chorchorus sps), Sunn hemp (Crotolaria juncea).
(b) Brush fibres : e.g. sps. of Borassus and Caryota ureans.
(c) Rough weaving fibres : e.g. Chinese mat grass (Cyperus corymbosus), Bamboo (Bambusa tulda), Japanese mat rush (Juncus effusus), Calamus, Pandanus, etc.
(d) Filling fibres : e.g. sps of Red silk cotton (Bombax ceiba; Simal), Kapok or Silk cotton (Ceiba pentandra; Safed simal), Calotropis, Typha, etc.
(e) Natural fibres : e.g. Tapa cloth (Broussonetia papyrifera), Hibiscus teliaceous, etc.
(f) Paper making fibres : e.g. Wild plants, Mulberry etc.
From the point of view of the origin, fibres are divided into three groups—
(a) Soft or Bast fibres : e.g. Jute, Flax, Hemp.
(b) Wood fibres : e.g. Brush fibres.
(c) Hard or Structural fibres : e.g. Coir (Cocos nucifera), Pineapple (Ananas comosus), Abaca or Manila hemp (Musa textiles).
Cereals
This kind of plants provide food for mankind. The cereals are the members of graminae family and develop caryopsis type of fruit. They provide a high percentage of carbohydrates together with proteins and small quantity of fats and vitamins. There are six types of true cereals—Rice, Wheat, Maize, Barley, Oats and Rye.
Wheat
(Triticum vulgare; Vern, Gehoon; Family Graminae)
Wheat is the main cereal of the world especially in the temperate region. Wheat is a gift of the old world to the new world. It originally comes form Persia and Afganistan.
Botanical characters : It is an annual grass belonging to genus Triticum. Wheat plant generally attain a height between 2 to 5 feet. The spikelet consists of 1 to 5 flowers enclosed by a pair of glumes. The mature edible grain is a one seeded dry fruit caryopsis where seed coat remains fused with the pericarp. A mature grain has an embryo, a starchy endosperm, and is enclosed in husk.
Climate : Wheat needs a temperate climate for growth. The sowing of wheat begins in early October and goes upto middle November. In India harvesting extends between mid January to June.
Kinds : Since the origin of wheat, today we have a large number of species and varieties. Haeckel has recognized 8 kinds of wheat.
Triticum monococcum = 2n = 14
T. dicoccum = 2n = 28
T. turgidum = 2n = 28
T. poeonicum = 2n = 28
T. spelta = 2n = 42
T. compactum = 2n = 42
T. durum = 2n = 28
T. vulgare = 2n = 42
The tetraploids are presumed to have originated from crossing between ‘Wild Einkorm’ and grass Aegilops speltoides. The common wheat recently evolved species. It is thought to have been evolved as a result of hybridization between tetraploid wheat and wild grass Aegilops squarossa.
Breeding : Continuous attempts have been made to develop new type of wheat which has a better yield, that matures early, does not lodge and resists disease and drought.
Today several new high yielding varieties are available to the farmer viz. Sonika (HD 1553), Sarbati Sonara, Kalyan Sona (HD 1593). Some disease resistant varieties developed include HD 2135, HD 2139 and CC 464.
Chemical constituents : The chemical composition of wheat varies considerably. The starch content varies from nearly 70% to less than 61%. The nitrogenous substances make up anything between 10 and 16-17%.
Wheat products : The flour of the wheat is extensively used for making bread, cakes, biscuits, pastries, chapatis etc. It is employed in the preparation of beer and other alcoholic beverages and industrial alcohol. It is also used for sizing the textile fibres. Wheat straw is used for seating chairs, stuffing mattresses and in the manufacture of straw carpet, straw hat basket etc. In India chapatis are made of wheat which people eat with great taste.
Rice or Paddy
(Oryza sativa; Vern. Dhan, Chawal; Family Graminae). Densely populated countries use this cereal and it seems that almost 50% of the world’s population feeds upon rice.
Botanical characters : Paddy is a large annual grass which usually attains a height of bout 2-6 feet. The spikelets are typically single flowered and laterally compressed. The fruits are one seeded. Grains with brown husk are referred to as paddy.
Climate : Rice mainly used by the people of tropical countries. It requires high temperature from 20OC to 25OC.
Cultivation and harvesting : The fields are ploughed thoroughly. The seeds are then grown in seed beds. The seedlings are transplanted to the field when 9 to 10 inches tall. In tropical countries 3 crops of rice are obtained. Aus, Aman and Boro. Aus is sown in May-June and harvested in September-October. Aman (lowland rice) is sown in June-July and harvested in November-December. Boro is sown in December-January and harvested in March-April.
Kinds : About 25 kinds of Oryza are known to the world which include around 7,000 varieties. Development of rice varieties is the main task of Rice Research Institute, Cuttack in India and International Rice Research Institute, Manila, Philippines. The high yielding varieties are now cultivated extensively which include T.N.I. JR> 8, Jaya Padma, Pankaj, Sabarmati etc.
Chemical constituents : Rice contains about 90% carbohydrates, about 8-10% proteins, 1% fats and about 1% mineral matters.
Uses : Rice provides the main staple food to large section of world population. Numerous preparations are known in different parts of the world. Bran oil is used as salad oil, as anti-corrosive lubricant and as rust resistant oil.
Pulses
Pulses are the rich source of proteins and belong to family leguminosae. They are very useful after cereals as a source of human food. They are highly proteinaceous but also contain carbohydrates, fats, minerals and vitamins. Roots of pulses develop root nodules in which are present nitrogen fixing bacteria. Some of the important pulses of India are—Gram, Pigeon pea, Black gram (Urd), Green gram (Moong), Lentil (Masur), Pea, Dew gram (Moth) etc.
Gram
(Cicer arietinum; Vern. Chana, Family Leguminoceae)
Legumes are important source of human food and contain more protein than any other products. Gram or chick pea is a native of southern Europe. Gram is small, much branched plant, attaining height of about 2 feet. Fruit is a legume or pod and contain 1-3 wrinkled seeds of colours.
The dry crop is grown in rabi season. It is mainly cultivated in U.P., Punjab, Rajasthan, M.P., Bihar, A.P., Maharashtra, W. Bengal, Tamilnadu and Karnataka.
Gram is eaten raw, boiled, roasted or cooked. They are salted, sweetened etc. Gram flour or besan is in common use for various preparations and as a substitute for wheat flour by diabetic peteints. The chaff (fruit walls of pods) are used as cattle feed. Germinated seed is recommended against scurvy.
Other Pulses and Legumes : The other well known pulses and legumes are Pea, Arhar, Moong, Urd, Soyabean etc. All these are rich sources of proteins. They are eaten in several ways.
Vegetable Oils and Fats
These are combustible substances. Faty oils are liquid at ordinary temperature and usually contain oleic acid. Fats are solid at room temperature and contain stearic and palmitic acids. Fatty oils are stored up in the seeds of plants. They are classified as—plants belonging to many families. They are generally classified under three categories—
(a) Drying oils : e.g. Linseed oil (Linum usitatissimum), Hemp oil (Cannabis sativa), Niger seed oil (Guizotia obyssinica), Tung oil (Aleurites montana), Sunflower oil (Helianthus annuus-Asteraceae), Poppy oil (Papaver somniferum) etc.
(b) Semidrying oils : e.g. Cotton seed oil (Gossypium hirsutum-Malvaceae), Sesame or Til oil (Sesamum indicum-Pedaliaceae), Corn oil (Zea mays) etc.
(c) Non-drying oils : e.g. Castor oil (Ricinus communis-Euphorbiaceae), Peanut or Ground nut or Moongphali oil (Arachis hypogea-Papilionaceae), Olive oil (Olea europeae) etc.
(d) Vegetable fats : e.g. Coconut oil (Cocos nucifera-Palmae), Palmoil, Mahua butter (Madhuca indica), Pongam oil, Nutmeg butter (Myristica fragrans) etc.
Groundnut oil
(Arachis hypogaea; Vern. Moongphali; Family Leguminoceae)
This plant is native of Brazil and an important source of oil. It is a non-drying oil plant. The seeds contain oil from 40 to 50%. The seeds are a source of an important vegetable oil which is often used for the manufacture of hydrogenated vanaspati and soap.
Groundnut is raised mostly as rainfed Kharif crop. India is in top position both in regard to acerage and production in the world.
The filtered and refined oil is edible being used as a salad oil for cooking making margarine etc. It is also used as fertilizer.
Essential Oils
These oils evaporate in contact with air and generally possess a pleasant fragrance and are also called volatile oils. Chemically they are very complex, found in many different seeds of plants. Some of the important essential oils are—
1. Camphor oil : Cinnamomrous camphora
2. Yang Yang oil : Cananga odorata
3. Cinnamon oil : Cinnamomum zeylanicum
4. Citrus oil : Citrus aurentifolia
5. Eucalyptus oil : Eucalyptus globulus
6. Jasmine oil : Jasminum auriculatum
7. Lavendor oil : lavendula officinalis
8. Mint oil : Mentha piperita
9. Lemon grass oil : Cymbopogon flexuosus
10. Sandal wood oil : Santalum album
11. Turpentine oil : Pinus longifolia
12. Rose oil : Rosa damascena.
Resins
Resins are the oxidation products of various essential oils. They have complex chemical composition, and are generally found in certain families of angiosperms. Generally they are yellowish solids insoluble in water but soluble in alcohol, turpentine and spirit. Some of the important resins are—
(a) Damars : e.g. Vateria indica, Hoyea odorata, Canarium strictum, etc.
(b) Lacquer : e.g. Rhus vernicifera, Melanorrhoea vasitata, etc.
(c) East Indian’s dragons blood: e.g. Deamonorpes kurzians.
(d) Benzoin : e.g. Styrax benzoin.
(e) Turpentine : e.g. Pinus roxburghii, Pinus wallichiana, etc.
(f) Cyclone gambose : e.g. Garcenia morella.
Sugar
Sugars are mainly produced by the process of photosynthesis. Sucrose is the main commercial sugar of the world. It is generally obtained from sugarcane and sugar beet.
Sugarcane
(Saccharum officinarum; Vern. Ganna; Family Graminae).
The large barrelled tropical species S. officinarum probably originated from wild species S. robustum in New Guinea region.
Botanical characters : The plant grows to a height of 8 to 12 feet or more and a diameter of two inches. It grows in clumps with bamboo like solid stems which contain 80% of juice with varying sugar contents.
Climate and cultivation : It grows best in warm humid weather. It is cultivated in a region with temperature ranging from 20 to 25OC. Sugarcane is propagated by cutting of varying lengths made from the upper joints of oil canes.
Sugarcane and Sugar in India
Sugarcane is the principal source of sugar in India and is highly valued as a cash crop. In North India about 80% of sugarcane is grown. Some of the high yielding varieties grown in the country include BO 11, CO 419, B 14, HM 320. Some of the disease resistant varieties are CO, 331, CO 213 and some popularly cultivated varieties are CO 513, CO 527, CO 321, etc.
Uses : Besides sugar there are three by-products result viz. bagasse, molasses and filter mud. It is very commonly used in the manufacture of rum and industrial alcohol. Other very common products from molasses are acetic acid (vineger) and glycerine.
Coal
Coal is a black or dark brown combustible mineral substance, composed of carbonised plant material found in beds in the earth and is largely mined for use as fuel. Coal was known to the natives from the time immemorial, but the first licence to dig coal in England was granted in 1239. In the beginning of 18th century coal mining started in India. Most of the coal raised in India has been obtained from the Gondwana system of strata of peninsular India. By 1906 main coal fields were in Raniganj and Jharia. After 1906 coal mining started in new fields like Giridih in Bengal, Pench valley, Narsinghpur district, Chanda district and Umaria.
The younger coals are nearly all of cretaceous and tertiary age, although some thin and poor seam of the upper jurassic age. Coal of tertiary age occurs in foot hills of Himalayas, eastern Assam and Andaman and Nicobar. Deposits in north-east Assam are youngest probably of miocene age.
Gondwana coal has excess of ash and moisture, while in the tertiary coal, percentage of ash is less but that of combustible matter is high; and so, it is a lighter fuel. Coal gas, coaltar and coke are related products of coal.
Best types of fossils are obtained from coal balls which are irregularly rounded masses ranging in diameter from a few millimeter to a meter. Each ball is a mass of calcium and magnesium carbonate, sometimes with iron sulphide. These show petrified remains of great number of plant fragments; even delicate parts remain intact in the coal balls.
Petroleum
Petroleum known as black diamond is otherwise known as mineral oil or rock oil or naphtha, is essentially a mixture of hydrocarbons of the paraffin and olefin series. It occurs when stored in loose textured conglomerates and sand stones, in which its distribution is similar to that of water in porous strata, being retained by impervious beds of clay. It may exude through any accidental fissure at the surface of the earth and may form a natural oil spring; but is chiefly obtained by boring through the impervious covering strata into the oil sands below, from which this oil is raised up by pumping.
In India petroleum is mainly confined to the two systems of folded rocks at either extremities of the Himalayas, only one of which (eastern) is in India.
Chemically petroleum is a liquid of varying composition. Kerosene, grease, gasoline, benzene and paraffin are some important petroleum products. It is also regarded as a modified form of fossil.
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