By: Aisha Shahbaz & Shikha Sharma

Everything we eat comes directly or indirectly from plants. An example of directly is fruits and vegetables. An example of indirectly is the meat and diary products that come from animals that feed on grain or grass.

The edible parts of plants can be grouped into three categories which are : Grow underground (potatoes and carrots) Grow above ground (lettuce) Seeds and fruits of plants Last category is the most significant as a food source since seeds are high in carbohydrates and protein. Legumes are a group of specialized fruit producing plants and a major source of food. The most important food crops for humans are the grains or cereals and the legumes. Sources of food come from roots, stems, leaves, fruits, and seeds

Population increases, which causes the farmers to become under pressure to produce as much food as they are capable of. Along with that they have to produce the food as cheaply as they can, because then when the food reaches the market, it is affordable for the customers. There are a variety of techniques used by farmers along with plant scientists to increase the crop yield.

Variation is common amongst species. Farmers select individual plants with desirable traits such as high yield and then use the seeds to plant the next years crop. After some time passes by,all members of the local plant population start to display the same desirable traits. This process has been used for centuries in the breeding of both plants and animals.

Is a process where two varieties are combined. They are two varieties that cross pollinate to produce “ daughter” plants. The “daughter” plants show both desired characteristics. Hybrid plants are both disease and frost resistant.

Cloning Techniques Many plants are able to reproduce asexually to make genetically identical copies of themselves, which is known as cloning Cutting is a section of plant tissue capable of growing into a new plant, which is the easiest cloning method A clump of a tissue is known as a callus which develops at the end of a cut stem, from which a root forms (figure 15.6) When the cutting which has grown roots is planted, it develops into a new plant, genetically identical to the same one from where the cutting came from This new plant is a clone of the actual parent plant Another method that is used to reproduce ornamental plants, and crops with desired characteristics, is by grafting Grafting is the attachment of a plant shoot to the rooted stem of another plant However, grafting only works if the plant has a tissue known as the cambium, but not all plants have it Cambium is a layer of meristematic plant tissue that makes new cells A bud from a plant with desired characteristics is grafted, or attached to the root of another plant, or to the rooted stem. The shoot is given the term scion Root is called the stock The plant that is grafted, grows as one “new” plant

This picture displays how the cloning technique works.

Control of Agricultural Pests Agricultural pesticides are chemicals that kill organisms that infect, eat, or compete with crops Insecticides kill insects Fungicides kill fungi Herbicides kill specific plants Most food plants cannot be grown without using these chemicals More than $750 million a year is spent on pesticides in Canada These chemicals have a bad effect on local biodiversity, as it can remain in the environment and can be harmful to humans and animals DDT is a very effective pesticide, and it was discovered that this chemical did not break down, instead it stayed in the environment DDT was harmful to animals, and was banned in Canada in 1969 Biological control is the use of a natural parasite, or predator to eliminate or control a pest Biological control also includes the use of plants that are chosen to keep agricultural pests away from crops Alfalfa was an important crop grown widely in the U.S. and Canada An insect called the alfalfa weevil began to eat the alfalfa plant, and is difficult to control it, even with pesticides Food irradiation is a technology used to preserve food Irradiation slows the growing of specific vegetables and fruits, which increases their storage life These radiations harm the DNA of the organisms that live in or on the food.

Genetically Modified Plants Whenever plant breeders do hybridization or breeding, the genetic makeup of plants is being modified. By doing this the breeders manipulate genes which naturally occur in the plant Transgenic organism is an organism that has DNA from another organism By using Agrobacterium tumefaciens, new DNS is introduced into a plant cell, which causes a tumour known as crown gall disease in some plants This bacterium produces crown gall disease in some plants A non-harmful strain of the bacteria is used The gene is put into the plasmid of the bacterium using recombinant DNA The cell grows and forms into callus, and then into a small plant The plant then gets cloned, and are planted as crops The plants are identical and show the desired characteristics that is made by the introduced gene Environmental conditions can lower crops yields, or even stop specific crop from being grown at all Other genetically modified crops have been used to make them insect-resistant Two examples of these plants are corns, and potatoes B. Thuringiensis (Bt) makes a protein that kills the insect Nitrogen compounds should be added to the soil in the form of fertilizers Legumes such, such as beans can convert atmospheric nitrogen into nitrogen compounds that the plants can use

Preserving Old Plant Varieties Monoculture is the cultivation of a single crop variety in a large area Planting a single variety of crop may be disastrous, as the genetically identical plants may be able to resist a certain fungal or bacterial disease If this happens, an entire crop might be wiped out Agricultural seeds of all types are stored in seed banks These seeds are important, because: the genes of a large number of varieties of an agriculture plant must be saved in case disasters happen

Many factors affect the development and use of plant technologies. On of these factors is the cost of developing the technology The cost is reflected in the price of the product. There are safety factors to consider when developing new plants Farmers have to decide which varieties of crops to grow so that it doesn’t lack anything. Lastly, consumer preferences also determine what plant technologies are developed and used.

Are you ready ? Goodluck

1. What are angiosperms? - Angiosperms are seed producers. 2. How many known species of angiosperms are there? - There are known species of angiosperms. 3. How many of them provide most of the worlds plant food supply? - Only 30 provide most of the world’s plant food supply. 4. What percent of the earths surface is suitable for food to be produced upon? - Only about 3% of Earth’s surface is suitable for food production. 5. What have farmers turned to for help? - Farmers have turned to science and technology for help

6. How many categories are edible plants grouped in? - Edible parts of plants can be grouped into three broad categories. 7. List the three categories that edible parts of plants are categorized in. - These three categories are parts that grow underground, parts that grow above, seeds and fruits of plants. 8. What are legumes? - Legumes are a group of specialized fruit producing plants and a major source of food. 9. What is selective breeding? Selective breeding is when human selection of certain individual organisms with desirable traits to breed and produce offspring with those traits, creating a new variety of a species. 10. What is hybridization? -Hybridization is a formation of an offspring from two parents of different varieties or different species.

11. What is a clone? A clone is a genetically identical copy of an organism 12. What is another name for root? Root is called the stock 13. What do insecticides, fungicides and herbicides do? Insecticides kill insects Fungicides kill fungi Herbicides kill specific plants 14. What is a DDT? DDT is a very effective pesticide, and it was discovered that this chemical did not break down, instead it stayed in the environment 15. What does Irradiation show? Irradiation shows the growing of certain vegetables, and fruits, increasing their storage life

16. What do radioactive emissions do to the DNA? These radioactive emissions damages the DNA of the organisms living on or in the food, which ends up destroying them 17. What can environmental conditions do? Environmental conditions can lower crops yields, or even stop specific crop from being grown at all 18. What was an Alfalfa, and where was it mostly grown? Alfalfa was an important crop grown widely in the U.S. and Canada 19. What happens by using Agrobacterium tumefaciens? By using Agrobacterium tumefaciens, new DNS is introduced into a plant cell, which causes a tumour known as crown gall disease in some plants 20. What is a monoculture? Monoculture is the cultivation of a single crop variety in a large area

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