Vegetables, Sugar, Spices & Rubber | Biology for Grade 12 PDF Download

VEGETABLES

Vegetables contain a large quantity of carbohydrates and mineral salts like calcium, iron, phosphorus, iodine etc.; they are also rich in vitamins, therefore, are included in our daily diet. 

Vegetables

Some of the important vegetables are as follows :-

(1) Potato (Solanum tuberosum-family solanaceae) :- Main vegetable crop is of potato. It is an erect, branched annual; tuber is modified stem, which have different shapes-round, oval and cylindrical; it is a native of Peru(South America) and was first introduced in India by the Portuguese in the early part of the 17 century; potato tubers are eaten as vegetable and in various other forms; they are also used in the production of starch and industrial alcohol.

(2) Tomato (Lycopersicon esculentum family Solanaceae) :-  It is a native of South Asia; it is cultivated in warm countries for its fruits of various shapes and colours, which are used as vegetable. Tomatoes are also used in the preparation of ketchup, sauce,soup and juice.

(3) Brinjal (Solanum melongena - family Solanaceae) :- It is an erect, branched, annual herb, fruit is large, ovoid, purple or whitish berry; it is a native of India. The fruits are eaten as vegetable for its high protein content.

(4) Okra (Bhindi) (Abelmoschus exculentus - family Malvaceae) :- It is an annual herb with yellow crimson centred flowers; it is grown in warm countries for its mucilaginous fruits; it is a native of tropical Africa. The fruits are used as vegetables and also in soup.

(5) Onion (Allium cepa - family Liliaceae) :- It is a native of South Asia. The food is stored in the bulb; bulbs of onion are popular as vegetable and are also used for flavouring and pickling. The leaves are also eaten as vegetable.

SUGAR

Sugars are the end products of photosynthesis in green plants. Cane- sugar or sucrose is the main commercial sugar used world over for sweetning various food products. Some of the important sugar yielding plants are as follows :-

(1) Sugarcane (Saccharum officinarum) :- It belongs to family Gramineae and is the chief source of sugar in India. The plant reaches a height of 6 to 12 feet and a diameter 1 to 2 inches: the stem is solid with many fibrous strands and contains juice; the stems are cut close to the ground and are then sent sugar mills for the extraction of sugar. Molasses is used in the manufacture of rum and industrial alcohol.

(2) Sugar-beet (Beta vulgaris) :- It belongs to family Chenopodiaceae and is the source of sugar in cold countries. The sugar-beet is a biennial herb with white tap root. Sugar is extracted from the fleshy roots which contain 15-20% of sucrose. In India sugar-beet is not much used as a source of sugar, but the roots and leaves are used as vegetables.

FIBRES

The fibre crops of the world rank second in importance to the food crops. Fibres are thread-like sclerenchymatous tissues obtained from different parts of the plant body. They are usually long with thick walls and pointed ends; the thickening of the walls is either due to the deposition of lignin or cellulose. Some of the important commercial fibres are as follows :-

(1) Cotton (Gossypium sp. - family Malavaceae) :- Cotton is the most important commercial textile fibres. It is used for a variety of purposes, especially in the manufacture of a large proportion of the clothing.

Fibres are produced by the seed coats of various species of gossypium and when separated from the seed are known as'lint'. Fibres are also used for making ropes, twines and threads; raw cotton is also used for stuffing pillows and cushions.

(2) Jute (Corchorus capsularis and C. olitorius - family Tiliaceae) :- It is a very valuable bast fibre and is second in use to cotton. The fibres are extracted by the process of retting in which the branches of plants are dipped in water for few days; after retting fibres are separated. Jute fibres are used for making gunny bags, packing cloth, carpets, cordage, curtains etc.

(3) Sunn hemp (Crotolaria juncea - family papilionaceae) :- The plants are extensively cultivated in India.

The long fibrous strands are made up of lignified phloem sclerenchyma tous cells, which are obtained after retting. The fibres are used in manufacture of ropes, canvas, nets, cordages etc.

(4) Flax (Linum usitatissimum - family Linaceae) :- The fibres are very strong, silky, short in length and are formed in thepericycle of the stem. Flax fibres are used in the manufacture of linen cloth, carpets, canvas, cigarette paper, insulating materials etc.

(5) Hemp (Cannabis sativa - family Cannabinaceae) :- The fibres are obtained from the pericycle after retting. The hemp fibres are long, strong and durable but lacks flexibility. It is used for the manufacture of ropes, cables, nets, canvas etc.

(6) Munj (Saccharum munja - family Gramineae) :- The fibre is obtained from the stem. It is used for making chair, tables, baskets, mats and ropes.

(7) Coir (CoCos nucifera - family palmae) :- It is obtained from the fibrous mesocarp of the fruit; the fruits are dipped in marine water for many months and then beaten to separate the fibres. Coir is used for making brushes, doormats, carpets, sacs, bags, cordage etc.

OILS

Oils are the complex chemical compounds which consists of hydrocarbons, esters, alcohols, aldehydes etc. The oils are of two kinds –

(i) Essential oils 

(ii) Fatty oils.There are several species of plants yielding both edible and industrial oils. Some of the important oils are –

(1) Groundnut oil is obtained from the seeds of Arachis hypogea - Family Papilionaceae: refined oil is used in cooking and oil is converted into vegetable ghee by hydrogenation.

(2) Gingelly or sesame oil is obtained from the seeds of Sesamum indicum - family Pedaliaceae; oil is used in cooking, medicine, soap etc.

(3) Coconut oil is obtained from the dry kernel of the seed of Cocos nucifera - family Palmae; oil is used for cooking as hair oil, and in the manufacture of soaps, shampoo, cosmetics etc.

(4) Mustard oil is obtained from the seeds of Brassica campestris - family cruciferae; oil is chiefly used for cooking purposes.

(5) Castor oil is obtained from the seeds of Ricinus communis - family euphorbiaceae; oil is used in medicines, as lubricant and also in making soaps.

(6) Soyabean oil is obtained from the seeds of Glycine max - family Papilionaceae; raw oil is used in the manufacture of soap, varnishes, paints etc.; refined oil is used for cooking purposes.

(7) Linseed oil is obtained from the seeds of Linum usitatissimum - family Linaceae; oil is used in making paints, varnishes, soaps etc.

TIMBER
Timber is the wood used for various building purposes, for making plywood, railway sleeper, ceiling, partition walls, doors, furniture, packing boxes etc. The quality of timber depends on its strength, weight, hardness and presence of natural depositions like tannins, resin etc. Some of the timber yielding plants are as follows :-

(1) Indian Redwood (Sesham) (Dalbergia sissoo - family Papilionaceae) - The wood is dark- brown in colour and is very strong and durable. It is used for making good quality furniture, carts, boats, poles etc

(2) Teak (Tectona grandis - family Verbenacea) – It is the most important wood as it is extremely durable. It is used for making best  quality furniture, houses, ship-building, for bridges, railway sleepers etc.

(3) Deodar (Cedrus deodara - family Pinaceae) :- The wood is light, extremely durable, yellowish-brown in colour. It is used for house-building bridges, railway sleepers, light furniture etc.

(4) Sal (Shorea robusta - family Dipterocarpaceae) :- The timber is very hard, heavy, strong and very durable. The wood is of brown colour and is used for beams, furniture, carts, bridges railway sleepers etc.

(5) Mahogany (Swietenia mahogoni - family Meliaceae) - It is a valuable timber tree. The wood is very hard and durable and is used for ,making boats, ships, furniture etc.

(6) Toon (Cedrella toona - family Meliaceae) – The timber is very light and is used for making furniture, houses, packing boxes etc.

(7) Mango (Mangifera indica-family Meliaceae) – The wood is strong, slightly lighter and grey or greyish brown in colour. It is used for door and window frames, packing cases and tea boxes.

BEVERAGES
These are mild agreeable and stimulating liquors meant for drinking. Beverages may be either non-alcoholic or alcoholic. Non-alcoholic beverages do not contain alcohol but instead, contain caffeine which is an alkaloid nonalcoholic beverages are as follows -

(1) Tea (Thea sinensis or Camellia sinensis - family Theaceae) – It is the most popular beverage; Prepared from the dried leaves of this plant. The plant is a native of Assam in India and now cultivated in China, India, Pakistan, Japan, Ceylon, England and Indonesia. The tea plant is a shrub 3-4 feet high. The tea leaves are picked by hand which are processed for obtaining different grades of tea leaves.

(2) Coffee (Coffea arabica and C.robusta - family Rubiaceae) :- Seeds of these plants are the sources of coffee. The seeds are dried in sun or by artificial heat and then roasted to develop flavour, aroma and colour.

Coffee plant is a shrub or small tree 16 to 25 feet high. Main coffee plantations are in the hill slopes of South India - Karnataka, Kerala and Tamil Nadu. It is a favourite drink all over India particularly South India. America consumes the largest quantity of coffee.

(3) Cocoa (Theobroma cacao - family Sterculiaceae) –  It is prepared from the seeds of this plant. The beans roasted in iron drums at a temperature of 125° C to 140° C. The seeds are finally ground to an oily paste to form the bitter chocolate. Sweet chocalate is made by adding sugar to the bitter chocolate Cocoa tree is a native of tropical Central and South America.

RUBBER
Rubber is obtained from the latex of Hevea brasiliensis - family Euphorbiaceae, which is the main source of commercial rubber. The latex is collected by tapping the bark, which is processed for obtaining final rubber.

It is used as tyres, tubes, rubber sheets, insulation of electric wires etc. The majority of rubber plantations are in Kerala, Tamil Nadu and Karnataka.

MEDICINAL PLANTS
Most of the medicinal plants are wild; these plants are collected and sent to the centres of researches to work out their medicinal value. A good number of them are cultivated on commercial basis. Some of the important drug yielding plants are -

(1) Opium (Papaver somniferum - family Papaveraceae) - The plant is an erect herb having large globose capsuls. Opium is the latex of unripe fruits. Opium contains several important alkaloids such as morphine, codeine, neopine etc. Opium has narcotic and sedative effect and is largely used to relieve pain as an intoxicant.

(2) Rauwolfia (Rauwolfia serpentina - family Apocynaceae) - It is an erect, perennial under shrub. The dried roots are an important source of an alkaloids pine and other alkaloids are serpentine, serpentinine, rauwolfine etc. The alkaloid reserpine is used in several patene drugs, as it has a depressant action on central nervous system and produces sedation and lowering of blood pressure.

(3) Cinchona (Cinchona officindalis - family Rubiaceae) – It is a famous quinine-yielding plant. Quinine is the most important drug obtained from the bark of this plant and also from other species i.e, C. ledgeriana, C. officinalisandC. cordifolia. Bark of these plants contains about 30 alkaloids including quinine, cinchonine, quinidine and cinchinidine, all of which are used in medicine. Quinine has been a great boon to mankind, as it is the only adequate cure for malaria.

(4) Belladona (Atropa belladona - family Solanaceae) – Belladona drug is obtained from the leaves of this plant. The plant is a perennial herb. Belladona is used extremely to relieve pain; besides it's leaves contain several alkaloids, chief among is atropine, used to dilate pupil of the eye.

(5) Ephedrine (Ephedra equisetina and E. sinica - family Gnetaceae) – Ephedra is a leafless shrub. The entire plant is used in the extraction of this drug. Ephedrine is used to cure asthama, colds and hay fevers.

(6) Aconite (Aconitum napellus - family Ranunculaceae) – Aconite is obtained from the tuberous roots of this plant.  A conite relieves pain due to neuralgia, rheumatism and inflammed joints; it is also used as a tonic and sedative.

SPICES
Spices cannot be grouped in food, as they have very little nutritive value. They give aroma and flavour to food.

They stimulate the appetite and increase the flow of gastric juices and for this they are often referred as food accessories. Some of the spices yielding plants are as follows –

(1) Clove (Laung) (Eugenia caryophyllus - family Myrtaceae) - It is  a native of Eastern Indonesia. Cloves are unopened flower buds which on maturity become brown and brittle. They are aromatic and are used for flavouring pickles, curries etc.

(2) Cinnamon (Dalchini) (Cinnamomum verum – family Lauraceae) – It is a native of Sri Lanka. The bark of this tree is a Cinnamon of commerce. Cinnamon has a pleasing, fragrant odour and a warm, sweet, aromatic taste. It is used for flavouring foods.

(3) Red pepper (Chillies) (Capsicum annum – family Solanaceae) – It is a native of tropical America and West Indies. The fruits are pod-like berries with many, small, flat seeds. The green chillies are used as vegetable, while the ripe red chillies are powdered and then used as spice. The pungency or spicy taste of chillies is due to a substance known as Capsaicin (C₁₈H₂₇NO₃), which is used in the manufacture of ginger beer.

(4) Black pepper (Kali mirch) (Piper nigrum - family Piperaceae) – it is a native of South-Western India.
The black pepper is the dried unripe fruit. It is one of important spices and widely used as flavouring substance.
The characteristic aroma of pepper is due to the presence of a volatile oil and the pungency is caused by the non-volatile oleoresin fraction and various alkaloids; piperine (C₁₇H₁₉NO₃) is the chief alkaloid.