Nutrition in Plants

Carbohydrates, proteins, fats, vitamins and minerals are essential components of food, these components are called nutrients, but Nutrition is the mode of taking food by an organism and its utilisation by the body.

Green plants are called autotrophs as they prepare their own food from simple substances, but animals and most other organisms are called heterotrophs as they take in ready-made food prepared by the plants

Leaves are called food factory of plants, as the synthesis of food takes place in leaves of plants. Water and minerals present in soil are absorbed by roots and transported to leaves via stem. Carbon dioxide from air is taken in through tiny pores on surface of leaves called stomata.

Refer section B answer no 3.

There are vessels inside a plant which run like pipes throughout the root, stem branches and leaves, by going through these vessels water and minerals are transported to leaves from roots.

Chlorophyll is the green colour pigment which helps leaves to capture energy from sunlight to carry out the food making process of plants by the leaves.

Chlorophyll is the green colour pigment which helps leaves to capture energy from sunlight to carry out the food making process of plants by the leaves. It is the green photosynthesis pigment which provides energy necessary for photosynthesis.

Photosynthesis is the food manufacturing process of green plants containing chlorophyll, in presence of sunlight, with the help of carbon dioxide and water to synthesise carbohydrates. The equation for the process is as follow:
Carbon dioxide + water —————> carbohydrate + Oxygen

Stomata are the tiny pores present on the surface of leaves which helps in exchange of gases, the pores in stomata are surrounded by guard cells.

Take a potted plant which has been exposed to sunlight and pluck a leave from the plant. Then boil it in water for 5 min to soften it and then place the leave in a test tube containing alcohol ,place the test tube in a beaker containing water gently heat the beaker till the alcohol dissolves in the chlorophyll and the leaves loses its green colour. Now wash the leaf with water and then place it on a plate and add a few drops of iodine solution the parts that turn blue black show the

All living organisms require food. Plants can make their food themselves by organic substances but animals including humans cannot make their food themselves. They get it from plants or animals that eat plants. Thus, humans and animals are directly or indirectly dependent on plants.

Living organisms need food to build their bodies, to grow, to repair damaged parts of their bodies and provide with energy to carry out life processes.

Only certain parts of plant like leaves have green pigment called chlorophyll. So Leaves are called the food factories of plants. Besides leaves, photosynthesis also takes place in other green parts of the plant like in green stems and green branches. The desert plants have scale or spine like leaves to reduce loss of water by transpiration. These plants have green stems which carry out the process of photosynthesis.

The body of living organisms are made of tiny units called cells, therefore Cell are called the building blocks of living organism. Cells can be seen only under the microscope. Some organisms are made of single cell they are called Unicellular. Ex. Amoeba, Paramecium etc. While others are made of multicells and are called multicellular. Ex. man, tree etc.

The cell is enclosed by a thin outer boundary, called the cell membrane Many cells have a distinct, centrally located spherical structure called the nucleus. The nucleus is surrounded by a jelly-like substance called cytoplasm.

Chlorophyll, sunlight, carbon dioxide and water are necessary to carry out the process of Photosynthesis.

Algae contain chlorophyll which gives them green colour and because of chlorophyll it can also prepare their own food by photosynthesis.

The main components presents in carbohydrates are carbon, hydrogen and oxygen.

Soil has certain bacteria that convert gaseous nitrogen into a usable form and release it into the soil. These soluble forms are absorbed by the plants along with water. By adding fertilizers rich in nitrogen to the soil farmers also made nitrogen available for plants.

The mode of by which parasitic organism get and synthesize their food is called parasitic nutrition. Example Cucuta. It does not have chlorophyll; it takes readymade food from the plant on which it is climbing. The plant on which it climbs is called a host. In a parasitic nutrition only one of the partners is benefited and other is not.

There are few plants which can trap insects and digest them. Such plants may be green or of some other colour. Such insect-eating plants are called insectivorous plants. Example: Venus Flytrap and Pitcher plant

This mode of nutrition in which organisms take in nutrients in solution form from dead and decaying matter is called saprotrophic nutrition. Plants which use saprotrophic mode of nutrition are called saprotrophs. Example Fungi that secrete digestive juices on the dead and decaying matter and convert it into a solution. Then they absorb the nutrients from it.

Refer section B answer no 26.

Some organisms live together and share shelter and nutrients. This is called symbiotic relationship. E.g. an alga, and a fungus live together fungus provides shelter, water and minerals to the alga and, in return, the alga provides food which it prepares by photosynthesis. In this kind of association both partners are benefited.

Nutrients are replenished in soil by following ways:

• By spreading manure or fertilizers that contain nutrients such as nitrogen in the fields
• By the bacterium Rhizobium that is commonly present in rot nodules of leguminous plant that can take atmospheric nitrogen and convert it into a soluble form like nitrates.

Symbiosis is the type of nutrition in which two different kinds of organisms depend on each other for their nutrition. In this both the organisms are benefitted by each other e.g., lichen is a symbiotic association between algae and fungi. In this one alga and one fungus live together and remain in symbiotic relationship.

Rhizobium is a type of bacteria that cannot make its own food and lives in the roots of gram, peas, moong beans and other legumes, it converts atmospheric nitrogen into useable form which increases the fertility of soil, and legumes provide food and shelter to the bacteria.

When an insect lands in the pitcher, the lid closes and the trapped insect gets entangled into the hair. The insect is digested by the digestive juices secreted in the pitcher.