کد خبر ۹۲۱ ۳۲۰ بازدید انتشار : ۱۹ اسفند ۱۳۹۵ ساعت ۲۱:۵۱

Uses of Plants

Human beings are completely dependent upon plants. Directly or indirectly, plants provide food, clothing, fuel, shelter,

Human beings are completely dependent upon plants. Directly or indirectly, plants provide food, clothing, fuel, shelter, and many other necessities of life. Humankind's dependence on crops such as wheat and corn (maize) is obvious, but without grass and grain the livestock that provide people with food and other animal products could not survive either.

Food
The food that plants store for their own growth is also the food that humans and other organisms need in order to live. In North America the chief food plants are cereal grains. (The word cereal comes from Ceres, the Roman goddess of agriculture.) Major cereal crops include corn (maize), wheat, oats, rice, barley, rye, and buckwheat. Legumes are the second greatest source of food from plants. Legumes such as peas, beans, soybeans, and peanuts are high in protein and oil. Sago, taro, and cassava are major starchy foods in certain tropical parts of the world. Seaweeds, an important part of the diet in some cultures, especially in Asia, are not actually plants but rather are a form of algae. 
Seasonings are derived from plant materials. People have used herbs and spices for centuries to flavor and preserve food. Some seasonings, such as pepper and nutmeg, are obtained from dried fruits. Others, including thyme, sage, and rosemary, come from leaves. Plant stems provide such spices as ginger and cinnamon. 
Many beverages come from plants. Coffee, tea, and cocoa are prepared by steeping plant material in hot water. Other drinks are “ready-made” by nature: orange, lemon, and grape juice; coconut milk; apple cider; and apricot nectar are examples. Some beverages come from processed plants, as do the cola drinks made from the kola nut of tropical America. 
Clothing
Much human clothing comes directly from plants. Cotton is the principal plant used for clothing. Synthetic fibers, such as rayon, are manufactured chiefly from cellulose, which is found mainly in the cell walls of plants. Linen is obtained from the flax plant. In addition, plants once furnished most of the dyestuffs with which cloth was colored. Today most dyes for this purpose are manufactured from coal tar, a plant product.
Paper
More than 4,500 years ago, the ancient Egyptians prepared the first paper from the fibrous stems of papyrus, a grasslike plant. It is from the name of this plant that the word paper is derived. In about AD 100 the Chinese invented a method of manufacturing paper that is still used today. Plant fibers are placed in water and reduced to a pulp. The water is sieved off, and the pulp is pressed and dried to yield a thin sheet of paper. Nearly any plant material that is rich in cellulose may be used to make pulp. Today, wood from such trees as pine and aspen is the most widely used source of pulp for paper.
Shelter and Various Products
Shelter in many parts of the world is made from wood. Plant materials appear in a number of places in human dwellings. Furniture is composed mainly of wood and cloth made from plant fibers. Walls are often covered with paper, and many paints and varnishes are derived from plant extracts. Products made from trees are numerous. They include chewing gum, cork, kapok, rubber, turpentine, gums and resins, and tannins. Trees also yield important fats and oils, such as cocoa butter and tung oil.
Cellulose, found in great abundance in many plant parts, is a basic ingredient of plastics and other synthetic substitutes for natural fibers, leather, glass, rubber, jewels, stone, and metal. Corn (maize) and soybeans have numerous industrial uses.
Fuel
Coal, oil, and gas are the chief fuels used for heating and cooking. All had their origin in green plants that lived on Earth long ago. Compression and heat converted these green plants to fossil fuels. Peat, formed by the same process as is coal, is a common fuel in Ireland and certain other countries.
Wood is still burned for heat in many parts of the world, and it is popular for use in open fireplaces. Charcoal, formed from incompletely burned wood, is a major fuel in many tropical countries where other fuels are unavailable or are very expensive. Charcoal is also popular in North America for outdoor cooking.
Medicine
Through the ages, people have found that certain plants relieve their aches and pains. Most medicine men and physicians in ancient cultures were experts on plants. In fact, the study of botany in Europe and America had its beginnings in medicine, when doctors searched for herbs to cure disease.
Many medicinal plants that were discovered by early peoples are still in use today. For example, some Native Americans chewed on the leaves of willows to relieve aches and pains. These leaves contain salicylic acid, a compound very similar to aspirin. The leaves of the foxglove yield digitalis, which is used to treat heart disease. Quinine, from the bark of the South American cinchona tree, was long used to combat malaria.
Medicines are still being discovered in plants. Vincristine, a medicine that has proved effective in the treatment of leukemia in children, was discovered in the common periwinkle plant. The periwinkle is native to South Africa and is cultivated in gardens around the world. Many plants are invaluable sources of vitamins, whose importance to human growth and health was an important 20th-century discovery.
Some plant drugs are violent poisons or habit-forming narcotics. These include peyote, which is derived from a cactus, and opium, which comes from a poppy.
Uses of Plants
Human beings are completely dependent upon plants. Directly or indirectly, plants provide food, clothing, fuel, shelter, and many other necessities of life. Humankind's dependence on crops such as wheat and corn (maize) is obvious, but without grass and grain the livestock that provide people with food and other animal products could not survive either.
Food
The food that plants store for their own growth is also the food that humans and other organisms need in order to live. In North America the chief food plants are cereal grains. (The word cereal comes from Ceres, the Roman goddess of agriculture.) Major cereal crops include corn (maize), wheat, oats, rice, barley, rye, and buckwheat. Legumes are the second greatest source of food from plants. Legumes such as peas, beans, soybeans, and peanuts are high in protein and oil. Sago, taro, and cassava are major starchy foods in certain tropical parts of the world. Seaweeds, an important part of the diet in some cultures, especially in Asia, are not actually plants but rather are a form of algae. 
Seasonings are derived from plant materials. People have used herbs and spices for centuries to flavor and preserve food. Some seasonings, such as pepper and nutmeg, are obtained from dried fruits. Others, including thyme, sage, and rosemary, come from leaves. Plant stems provide such spices as ginger and cinnamon. 
Many beverages come from plants. Coffee, tea, and cocoa are prepared by steeping plant material in hot water. Other drinks are “ready-made” by nature: orange, lemon, and grape juice; coconut milk; apple cider; and apricot nectar are examples. Some beverages come from processed plants, as do the cola drinks made from the kola nut of tropical America. 
Clothing
Much human clothing comes directly from plants. Cotton is the principal plant used for clothing. Synthetic fibers, such as rayon, are manufactured chiefly from cellulose, which is found mainly in the cell walls of plants. Linen is obtained from the flax plant. In addition, plants once furnished most of the dyestuffs with which cloth was colored. Today most dyes for this purpose are manufactured from coal tar, a plant product.
Paper
More than 4,500 years ago, the ancient Egyptians prepared the first paper from the fibrous stems of papyrus, a grasslike plant. It is from the name of this plant that the word paper is derived. In about AD 100 the Chinese invented a method of manufacturing paper that is still used today. Plant fibers are placed in water and reduced to a pulp. The water is sieved off, and the pulp is pressed and dried to yield a thin sheet of paper. Nearly any plant material that is rich in cellulose may be used to make pulp. Today, wood from such trees as pine and aspen is the most widely used source of pulp for paper.
Shelter and Various Products
Shelter in many parts of the world is made from wood. Plant materials appear in a number of places in human dwellings. Furniture is composed mainly of wood and cloth made from plant fibers. Walls are often covered with paper, and many paints and varnishes are derived from plant extracts. Products made from trees are numerous. They include chewing gum, cork, kapok, rubber, turpentine, gums and resins, and tannins. Trees also yield important fats and oils, such as cocoa butter and tung oil.
Cellulose, found in great abundance in many plant parts, is a basic ingredient of plastics and other synthetic substitutes for natural fibers, leather, glass, rubber, jewels, stone, and metal. Corn (maize) and soybeans have numerous industrial uses.
Fuel
Coal, oil, and gas are the chief fuels used for heating and cooking. All had their origin in green plants that lived on Earth long ago. Compression and heat converted these green plants to fossil fuels. Peat, formed by the same process as is coal, is a common fuel in Ireland and certain other countries.
Wood is still burned for heat in many parts of the world, and it is popular for use in open fireplaces. Charcoal, formed from incompletely burned wood, is a major fuel in many tropical countries where other fuels are unavailable or are very expensive. Charcoal is also popular in North America for outdoor cooking.
Medicine
Through the ages, people have found that certain plants relieve their aches and pains. Most medicine men and physicians in ancient cultures were experts on plants. In fact, the study of botany in Europe and America had its beginnings in medicine, when doctors searched for herbs to cure disease.
Many medicinal plants that were discovered by early peoples are still in use today. For example, some Native Americans chewed on the leaves of willows to relieve aches and pains. These leaves contain salicylic acid, a compound very similar to aspirin. The leaves of the foxglove yield digitalis, which is used to treat heart disease. Quinine, from the bark of the South American cinchona tree, was long used to combat malaria.
Medicines are still being discovered in plants. Vincristine, a medicine that has proved effective in the treatment of leukemia in children, was discovered in the common periwinkle plant. The periwinkle is native to South Africa and is cultivated in gardens around the world. Many plants are invaluable sources of vitamins, whose importance to human growth and health was an important 20th-century discovery.
Some plant drugs are violent poisons or habit-forming narcotics. These include peyote, which is derived from a cactus, and opium, which comes from a poppy.
 
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