Respiration in plants


Breathing is the lifesaver of almost every organism irrespective of the plants or animals. In the case of plants, it won`t be appropriate to use the term breathing as they lack lungs, instead, they respire through their leaves.  In other words, plant respiration is the mere exchange of gases without the mechanical action.  Let us discuss the mechanism of plant respiration and the parts of the plants assisting in the respiration.


A brief about plant respiration

Respiration is scientifically divided into external and internal respiration. Internal respiration is also known as cellular respiration where carbon enters in and oxygen exit out of the plant`s system. Plants exchange gases by taking carbon dioxide in and release the oxygen. They use many green parts of the plant, especially the leaves where photosynthesis take place. Precisely, they use stomata (found on the upper layer leaves), lenticels (present in stems) and roots for gas exchange. Through cellular respiration, plants produce glucose molecules with the help of photosynthesis; hence, photosynthesis is closely linked with the plant`s cellular respiration. Plants are autotrophs becasue they produce the food and oxygen required by animals. Plant Respiration and Photosynthesis undergoes following chemical variations to produce the carbon dioxide, water, and heat energy.

i.e.  Oxygen + glucose -> carbon dioxide + water + heat energy. In the case of photosynthesis, oxygen and glucose is released, I.e. carbon dioxide + water+ light energy -> oxygen + glucose.


The Process of Respiration in Plants

Parts of plant



Respiration in Leaves

Leaves are the primary morphological structures necessary for photosynthesis. The exchange of gases takes place through tiny pores found on the leaf`s surface known as stomata. The stromal openings provide an opportunity to absorb the necessary carbon dioxide through the process of diffusion.

Stomal openings in leaf


Respiration In Roots

Although roots doesn’t expose to sunlight, the underground part of the plants is responsible for absorbing the air from the air spaces found between the soil particles. This air is transferred to the green parts of the plant to further distribute into the system.


Respiration In Stems

The air coming in contact with the stem is absorbed and eventually diffused towards the leaves. The stomata found in the leaves allow the air to pass through various parts of the cell for respiration and the process continues as usual. The CO2 produced during this stage also dispersed through the stomata. In higher woody plants, the gaseous exchange is carried out by lenticels.


Aerobic and anaerobic respiration

Aerobic respiration is a form of exchange of gases but in anaerobic respiration, gases are not exchanges. The following table illustrates the differences between anaerobic and aerobic respiration.  

Aerobic Respiration

Anaerobic Respiration

Aerobic respiration takes place both in the cytoplasm and the mitochondria.

Only cytoplasm is responsible for anaerobic respiration

Aerobic respiration demands the presence of oxygen.

Oxygen is not necessary for anaerobic process.

Aerobic respiration help in gas exchange.

Gases are not exchanged during the anaerobic process.

Glucose breaks down into carbon dioxide and water.

Glucose breaks down into ethyl alcohol, carbon dioxide, and energy

All higher organisms such as mammals adapt the aerobic respiration.

Primitive organisms such as bacteria and yeast use anaerobic respiration.


Differences between Respiration and Photosynthesis



It is absent in animals and mammalian species.

Respiration is present in all organisms in different forms.

Photosynthesis produces glucose- foods.

Respiration is an oxidation process

Photosynthesis stores energy.

It helps to release energy.

Photosynthesis is an anabolic process.

Respiration is a catabolic process.

It is an endodermal process.

It is an exothermal process.

Sunlight is required for photosynthesis

It takes place even in the absence of oxygen.


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