Respiration In Plants

All living organisms, including plants, receive their energy required for their survival from a chain of chemical reactions called respiration.

What is Respiration

Respiration is a biochemical process, which is defined as the movement of air between the external environment and the cell, tissues of a living species. In this process, oxygen gas is inhaled in and carbon dioxide gas is exhaled out. It is referred to as a metabolic process, as an organism obtains energy by oxidizing nutrients and releasing waste products.

Also, refer to Respiration – A Life Process

Do Plants Breathe?

Yes, like animals and humans plants also breathe.

Plants do require oxygen for respiration which in return give out carbon dioxide. Unlike animals and humans, plants do not have any specialized structures for gaseous exchange but they have stomata (present in leaves) and lenticels (present in stems) which are involved in the exchange of gases. Compared to animals and humans, plant roots, stems, and leaves respire at a very lower rate.

It is important to note here that respiration is not equal to breathing. Breathing is just a part of respiration that takes place in both humans and animals. Plants respire throughout its lifespan as the plant cell require energy for their survival, but plants do not breathe as humans and animals do.  They breathe through the process called Cellular respiration.

In this process of cellular respiration, plants produce glucose molecules through photosynthesis process by capturing the solar energy and converting it into glucose. There are many live experiments to prove that plants do breath. All plants do respire to provide energy for their cells to stay active or alive.

Let’s have a glance at the process of respiration in plants.

The Process of Respiration in Plants

During respiration, very little amount of gas exchanges takes place within the different parts of the plants. Therefore, each part takes care of its own energy requirements.

Roots, stems, and leaves of plants exchange gases for respiration separately. As we all know, leaves have tiny pores called stomata, which is used for the exchange of gases. The oxygen, taken in through stomata is used by cells in the leaves to break down glucose into carbon dioxide and water.

Respiration in Plants

Respiration In Roots

Roots, the underground part of the plants absorb air from the air spaces present between the soil particles. Thus, the oxygen absorbed through roots are used to release energy which is later utilized for the transportation of minerals and salts from the soil.

Respiration in Roots

We are aware of the fact that plants have the unique ability to photosynthesize. Photosynthesis is the process by which plants prepare their own food. It takes place only in the parts of plants that contain chlorophyll, i.e. only in the green parts of the plants. The process of photosynthesis is so prominent that it sometimes masks the process of respiration in plants. However, we must know that respiration in plants occurs throughout the day while photosynthesis process takes place only in the presence of light. Therefore, at night the respiration in plants becomes prominent.

That is why we often hear that people are asked not to sleep under a tree at night. This may cause suffocation due to the excessive presence of carbon dioxide released by trees as a result of respiration.

Respiration In Stems

Respiration In Stems- Lenticels

In the case of the stem, the air gets diffused in the stomata and passes through various parts of the cell for respiration. The carbon dioxide produced during this stage also diffuses through the stomata. In higher plants or woody plants, the gaseous exchange is carried out by lenticels.

Respiration In Leaves

Respiration In Leaves - Opening and Closing the Stomata

Leaves comprise of tiny pores referred to as stomata. The exchange of gases takes place via stomata through the process of diffusion. Each stoma is controlled by Guard Cells. The opening and closing of the stoma help in the exchange of gases between the atmosphere and the interior of Leaves.

Differences between Respiration and Photosynthesis

Photosynthesis   Respiration
This process is common to all green plants containing chlorophyll pigments. This process is common to all living things including plants, animals, birds, etc.
It synthesizes foods. It oxidizes foods.
It stores energy. It releases energy.
Photosynthesis is an anabolic process. Respiration is a catabolic process.
It requires cytochrome. It also requires cytochrome.
It is Endothermal process. It is Exothermal process.
It is comprised of products like sugar, oxygen, and water as products. It is comprised of products like hydrogen and carbon-dioxide.
During Photosynthesis, radiant energy is converted into potential energy. During Respiration, potential energy is converted into kinetic energy.
It takes place only in the presence of sunlight. It takes place continuously throughout the life process from birth to death.

Also, refer to the Difference Between Photosynthesis and Cellular Respiration

Types of Respiration

There are two main types of respiration.  

Aerobic Respiration

  • Aerobic Respiration

This type of respiration occurs within the mitochondria of all eukaryotic organisms. In this process, food molecules are completely oxidized into the water, carbon dioxide and energy is released in the presence of oxygen. All higher organisms respire aerobically and this process requires atmospheric oxygen.

  • Anaerobic Respiration

This type of respiration occurs within the cytoplasm of prokaryotic organisms like bacteria and yeast. In this process, less energy is released due to the incomplete oxidation of food in the absence of oxygen. Carbon dioxide and Ethyl alcohol are produced during anaerobic respiration.

Also, refer to Respiration  and its Types 

Important Questions for you?

  • How do plants breathe?

All green plants breathe through the process of Cellular respiration. In this process, nutrients obtained from the soil are converted into energy and are used for different cellular activities.

  • Do plants breathe at night?

Yes, plants breath throughout its life span both during the day and night. The chemical equation of cellular respiration is expressed as  — oxygen + glucose -> carbon dioxide + water + heat energy.

  • Name the respiratory organ in woody stems?

In hard and woody stems, respiration or the exchange of gases takes place through lenticels. They are the small pores, scattered all over the bark and are found in all trees.

  • What is the role of stomata in plant’s respiration?

Stomata are the tiny pores located on the epidermis of leaves, stems, and other organs. During Cellular respiration, stomata facilitate gas exchange by opening and closing of the pores.

  • Which part of roots is involved in the exchange of respiratory gases?

Root hairs, the tubular extensions of the epidermis are involved in the exchange of respiratory gases.

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Practise This Question

The product of anaerobic respiration in muscles is: