Respiration in plants:

Plants are also living beings as like other animals. They also require energy for their growth and development. The chain of chemical reactions, by which plants fulfil their energy needs is said to be respiration in plants. In another way, we can say it is a process by which cells obtain chemical energy by the intake of oxygen and the release of carbon dioxide.

As we know the plant is also a living being like us, several questions arise in our mind. Do plants breathe? What is the process of respiration in plants? Do plants also have organs for respiration like us? The answer to all these questions is provided in this article. Read further to clear your doubts related to respiration in plants.

Do plants breathe?

• Yes of course! Plants also breathe by taking oxygen and releasing carbon dioxide.
• As animals have specialized organs to breathe, plants exchange gases through stomata, lenticels and roots.
• Stomata is present in leaves and lenticels are there in roots.
• The rate of respiration in plants is very slow as compared to animals.
• As we discussed the difference between breathing and respiration in the previous article. Both are the different process.
• The process of breathing in plants carries on the cellular respiration in plants.

Respiration process in plants:

• Respiration process involves different parts of the plants i.e. leaves, stem and roots.
• There is very little amount of gas exchanges takes place at each part.
• Therefore, each part fulfils their own energy requirements.
• In the leaves, there are tiny pores which are stomata where the gaseous exchange take place.
• Respiration in plants occurs 24 hours while photosynthesis takes place only in the presence of light.
• The amount of carbon dioxide released in the daytime is much less than the amount of oxygen produced as a result of photosynthesis.
• At night one is advised not to sleep under the tree as it may cause suffocation due to excess carbon dioxide released due to respiration.
• The oxygen diffuses in the plant through stomata and cells in the leaves uses it to break down glucose into carbon dioxide and water.

Glucose + Oxygen → Carbon Dioxide + Water + Energy

Respiration in different parts of plants:

As earlier discussed different parts of plant performs respiration separately. So let’s read about their mechanism separately.

Respiration in Roots:

• Respiration in plants also takes place through roots.
• Oxygen mixed air is present in the space between soil particles.
• Root has root hairs (lies at spaces between soil particles) by which the oxygen gets absorbed into roots.
• From root hairs, the absorbed oxygen supplies to all the parts of roots for respiration.
• Within the roots, carbon dioxide the product, releases from the same root hairs.

Respiration in Stems:

• Plants having green stem (mainly herbs and shrubs) has stomata present in it.
• Oxygen from the air diffuses in through stomata and Carbon dioxide released from the same surface.
• While the trees having hard and woody stem has lenticels present in it by which exchanges of gases takes place.
• Lenticels are loosely packed dead cells, present as small pores on the bark of woody plants or old roots uprooted from the earth.
• By the process of diffusion, oxygen reaches the intercellular spaces of the interior tissues and carbon dioxide released into the atmosphere. Thus the process of respiration in stems continues.

Respiration in Leaves:

• The leaves of a plant contain tiny pores which are stomata.
• Through stomata the exchange of air in leaves take place.
• At the lower surface of leaves of the plant, stomata are present in large number.
• Opening and closing of stomata are regulated by guard cells (bean shaped) present in it.
• Oxygen from the surrounding gets diffused in through stomata and carbon dioxide formed in plant gets released in the surrounding through stomata itself.
• Thus respiration process continues by these process.

Steps involved in the mechanism of respiration:

There are two major steps in the mechanism of respiration in plants:

• Glycolysis:

The conversion of glucose into pyruvic acid involving a series of enzymatic reactions in the process of respiration in plants. These reactions take place in the cytosol. These series of reactions is glycolysis.

Glucose → (enzymatic action) → Pyruvic acid

• Kreb’s cycle:

Kerb’s cycle involves the process of conversion of pyruvic acid into carbon dioxide, water and energy. The pyruvic acid formed after the process of glycolysis moves into mitochondria. At this place, several enzymes catalyse the reactions and their is formation of CO₂ and water. This series of enzymatic reactions is Krebs cycle.

Pyruvic Acid → (enzymatic action inside mitochondria) → CO₂ + Water

Differences between Photosynthesis and Respiration:

There are two types of respiration i.e. Aerobic and anaerobic respiration. You can refer to the respiration page.