Nutrition In Plants

Nutrition: -(पोषण) The breaking down of food into various nutrients by chemical processes in the body of all organisms to give out energy is      called nutrition.

Plants make their food by the process of photosynthesis, but animals cannot make their food themselves.

Nutrient: – (पोषक तत्व) The ingredients(अवयव) of food are called nutrients.

There are seven ingredients like Carbohydrates, Fats, Protein, Vitamin, Minerals, water and fibre.

Two types of nutrition:

Autotrophic nutrition (स्वपोषण)

Heterotrophic nutrition (परपोषण)

Autotrophic nutrition: – The mode of nutrition in which organisms make food themselves is called autotrophic nutrition.   Ex: – Green plants

The organisms in which occurs autotrophic nutrition are called autotrophs(स्वपोषी).

Green plants are called autotrophs because they make their food themselves by the process of Photosynthesis.

Photosynthesis: –  The process by which green plants make their own food from water and carbon dioxide in the presence of sun light is called photosynthesis.

The process of photosynthesis takes place in the green leaves of a plant.

Leaves are called the kitchen/factory of plants.

The green plants convert sunlight energy into chemical energy by making carbohydrates.

Oxygen is released during photosynthesis and carbon dioxide takes in by the plants.

Photosynthesis occurs only in daytime hence plants take O2 and release CO₂ in night. This is reason to don’t sleep under the tree in night.

Note-

The food is prepared by the green leaves in the form of a simple sugar called glucose.

The extra glucose is changed into another food called starch. This starch is stored in the leaves of the plant.

Raw materials for building plant’s body

The plants need raw materials such as nitrogen, phosphorus, iron and magnesium, etc., for building their body.

The plants take these materials from the soil.

Nitrogen is essential element used by the plants to make proteins and another compound.

Conditions necessary for photosynthesis/ Raw materials for photosynthesis:

The conditions necessary for photosynthesis to take place are:
Sunlight                Chlorophyll          Carbon Dioxide (CO₂)              Water (H₂O)

The photosynthesis takes place in the following three steps:

1. Absorption of sunlight energy by chlorophyll.

2. Conversion of light energy into chemical energy, and splitting of water into hydrogen and oxygen by light energy.
3. Reduction of carbon dioxide by hydrogen to form carbohydrate like glucose by utilizing the chemical energy.

Stomata: –    The large number of tiny pores present on the surface of the leaves is called stomata.

Stomata presences on the lower surface and edge of leaves. Due to this it decrease the loss of water.

The stomatal pore is surrounded by a pair of guard cells. The opening and closing of stomatal pores are controlled by the guard cells.

The plants obtain CO₂ and O₂ gas through the stomata.

How the plants obtain water for photosynthesis:

Plants absorb water through roots from the soil. The process of absorbing water by plants through the soil is called osmosis.

The water absorbed by the roots of the plants is transported upward through the xylem vessels to the leaves where it reaches the photosynthetic cells.

Site of photosynthesis: Chloroplasts

Photosynthes takes place in the leaves of the plants.

Leaves have green pigment called chlorophyll

Chlorophyll captures the solar energy which is then used to prepare food in plants. So, we can say that Sun is ultimate source of energy for all living organisms.

Other Notes on Photosynthesis

Photosynthesis can also take place in other green parts like green stems, green branches.

The simplest food synthesized by plants is called Glucose (simple carbohydrates).

The glucose made by plants is converted into complex carbohydrates which is called starch.

The simple carbohydrates are used to synthesise other components of food such as proteins carbohydrate, vitamins and fats.

Proteins are nitrogenous substances. Plants prepare proteins with the help of nitrogen which is obtained from the soil. 

Plants use the minerals dissolved in water to convert Glucose (simple carbohydrates) into carbohydrates, proteins and fats.

Photosynthesis is important because

1. 1. It provides food to animals including human beings.
   2. It puts oxygen gas into the air which is essential for breathing and respiration in animals including human beings.

Heterotrophic nutrition: –       The mode of nutrition in which organisms take in readymade food prepared by the plants are called heterotrophic     nutrition.    Ex: –  Animals

The organisms in which occurs heterotrophic nutrition are called heterotrophs(परपोषी).

Types of heterotrophic nutrition in plants

Most of the plants have green pigment called chlorophyll and can make their own food.

Some plants do not have chlorophyll and cannot synthesize their own food are called Heterotrophic plants.

Ex- Venus flytrap, California, Drosera Capensis etc.

Format: –  The mode of nutrition in which plants/animals ………………. for their food (nourishment) is called …………… mode of nutrition.

Parasitic nutrition: – The mode of nutrition in which plants/animals depend on other plants or animals for their food (nourishment) is called            parasites mode of nutrition.

Those plants that dependent on other plants or animals for food are called parasites plants.

Ex: –  Parasites Plants- Cuscuta (akash-bel), Cassytha (amar-bel),

Those animals that dependent on other plants or animals for food are called parasites animals.

1. Endo parasites (inside the host)- hookworms, tapeworms, leeches, Round worm, Puccinia (a fungus)
2. Ecto parasites (outside the host)- Ex-leeches, mosquitos,

The ones on which parasites depend are called hosts. 

A parasite plant climbs on the host plant from which they get all the food.

The host does not get any benefit from the parasite.

The plants that have green leaves and can synthesis their food but they are dependent on other plants for shelter and water are called partial parasitic plants.   Ex – Dodder or cuscuta

Insectivorous mode of nutrition: –         The mode of nutrition in which plants depends on insects for food are called insectivorous mode of            nutrition.         

Those plants that eat insects are called insectivorous plants.      

Ex: –  Pitcher plant, Venus fly trap etc.

Those animals that eat insects are called insectivorous animals.

Ex: –  Frog, Lizard, Snake etc.

These types of plants purely depend on other insects and small animals for their nutrition.

Pitcher plants trap small insects inside the pitcher and insects are digested by the digestive juices secreted in the pitcher plants.

Insectivorous plants grow in those soils which do not contain sufficient nitrogen mineral.

These types of plants are green and carry out photosynthesis to obtain a part of food.

An insectivore plant absorbs nutrients from an insect. The digestive juices that secrete by cells of the plant digest the insect.

Saprophytic mode of nutrition: – The mode of nutrition in which organisms or plants that obtain their nutrition from dead and decaying organic      matter is called Saprophytic mode of nutrition.

Those plants which obtain their nutrition from dead and decaying organic matter are called saprotrophs. 

Ex: –  Moulds, mushrooms, yeasts and some bacteria.

Saprotrophs secrete digestive juices onto dead and decaying matter to dissolve it and then absorb nutrients from it.

hose animals which obtain their nutrition from dead and decaying organic matter are called saprotrophs.       

         Ex: –  Moulds, mushrooms, yeasts and some bacteria.

Symbiotic mode of nutrition: –     The mode of nutrition in which there is a close relation between two different plants of different categories

are called Symbiotic mode of  nutrition.

In such type of association both the plants get benefited.

Ex- Certain fungi live in the roots of the trees. In this case tree provides nutrients to fungi and in return receives help from it to take up water and nutrients from the soil.

How nutrients are replenished in the soil

We know that plants continuously take nutrients from the soil in order to synthesize food. As a result of this amount of nutrients in the soil decreases.

Nutrients in the soil are replenished by adding fertilisers and manures.

Fertilisers and manures contain plants nutrients and minerals like nitrogen, phosphorus and potassium.

Another way to replenish soil is to grow leguminous crops (for example gram, peas, pulses etc.) in the soil.

The bacteria Rhizobium can take atmospheric nitrogen and convert it into a soluble form.

But Rhizobium cannot make its own food. So it lives in the roots of gram, peas, moong, beans and other legumes and provides them with nitrogen. In return plants provide food and shelter to the bacteria.

Thus plants and bacteria have a symbiotic relationship here.

Why are Nitrogenous fertilizers not added in soil in which leguminous plants are grown?

Nitrogenous fertilizers are not added in soil in which leguminous plants are grown because a bacteria Rhizobium can take atmospheric Nitrogen  and convert it into a soluble form that the plants can absorb.

How will you test a leaf for starch? Mention any precaution you will take?

1. Pluck a leaf from a plants which has been exposed to sunlight.
2. Boil it for about few minutes in water to soften it.
3. Place it in a test tube containing alcohol.
4. Place this test tube in a beaker of water and warm the water gently until the alcohol begins to boil. (caution: Do not allow the water in the beaker to boil).
5. The alcohol will dissolve the chlorophyll and the leaf will lose its green color.
6. Wash the leaf in the warm water to remove the alcohol.
7. Now spread the leaf out on a white tile and pour iodine solution on it with water.
8. Hold it up against the light.
9. You will observe that parts of the leaf become blue black. These parts of the leaf have starch in them.

How do plants get Nitrogen to synthesize proteins?

Answer: The air contains large amounts of Nitrogen but plants cannot absorb Nitrogen directly. They get Nitrogen in two ways: –

Soil contains certain bacteria called Rhizobium that can convert atmospheric Nitrogen into water – soluble compounds. Plants absorb these compounds along with water to get Nitrogen.

Farmers add fertilizers rich in Nitrogen to the soil. These are absorbed by plants.

Why are manures and fertilizers added to the soil in a form?

Answer: Manures and fertilizers are added to the soil to enrich the soil with required nutrients and nitrogen, so that plants grow rapidly and nutrients get replenished in the soil. These fertilizers add nutrients like Nitrogen, Phosphorus, Potassium to the soil.

Distinguish between parasites and partial parasites in plants giving one examples of each

Parasitic Plants	Partial Parasitic Plants
The plants which obtain their nutrients from other plants are called parasitic plants. Ex- mistletoe plant or loranthus	The plants that have green leaves and can synthesis their food but are dependent on other plants for shelter and water are called partial parasitic plants. Ex- Dodder or cuscuta

Why do organism need to take food?

Answer: Food is needed by all living organisms for four main purposes:

1. An important function of food is to help a living organism to grow, if enough food is not given or it is not of right kind, growth will not be sufficient or healthy.
2. Second important function of food is to provide energy.
3. We need energy for doing physical work. We use more energy when we run than we walk and less energy when we sleep.
4. Food is also needed by living beings for replacement and repairing their damaged body parts.
5. Food gives us resistance against diseases and protects us from infections.

How humans and animals are directly or indirectly dependent on plants.

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

Question: Give a brief description of the process of synthesis of food in green plants.

Answer: The process by which the green plants synthesize their own food in the presence of sunlight and chlorophyll by taking carbon dioxide from the atmosphere and water from the soil is known as photosynthesis. Green plants require four things to prepare their own food. These are :

1. Carbon dioxide, absorbed from the atmosphere through stomata present on the leaf surface.
2. Water, absorbed from the soil, through the root system.
3. Chlorophyll, present in the leaf.
4. Light, coming from the sun. During photosynthesis, food is synthesized. Oxygen is released in the process.