Respiration in plants

Introduction

Breathing is the first and foremost physiological process as most of the organisms required to do this in order to survive. When it comes to plants, it won`t be appropriate to use the term breathing, instead, they respire. The difference between breathing and respiration is that breathing refers to the action of inspiration and expiration where lungs play their role; whereas respiration may or may not involve the action of lungs. Otherwise, respiration is the mere exchange of gases with or without the mechanical action of breathing. Respiration is more of a chemical process whereas breathing refers to the ventilation of air in and out of lungs. Let us discuss the process of respiration in plants and their underlying mechanisms as well as the parts of the plants assisting in this process.

Table of Contents

1. Introduction

2. A brief about plant respiration

3. The Process of Respiration in Plants

    3.1 Respiration in Leaves

    3.2 Respiration In Roots

    3.3 Respiration In Stems

4. Aerobic and anaerobic respiration

5. Differences between Respiration and  Photosynthesis

 

A brief about plant respiration

Like all other animals, plants breathe but technically it is appropriate to use the term plant respiration instead of plant breathing as there are no lungs involved in the process. Unlike animals, plants take carbon dioxide in and give away the oxygen –a revers happen in the case of animals. Plants use stomata (found on the upper layer leaves), lenticels (present in stems) and roots for gas exchange. However, plant leaves play a major role. Respiration is scientifically divided into external and internal. Internal respiration is also known as cellular respiration. In the external respiration, there is inhalation and exhalation but no metabolic respiration is involved whereas in the cell level respiration it is all about chemical, enzymatic and physiologic processes that exchange the co2 and 02. Through cellular respiration, plants produce glucose molecules with the help of photosynthesis; hence, photosynthesis is closely linked with the plant`s cellular respiration. So, all the plants do respire to produce the required food and oxygen for 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 re the primary morphological areas 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 absorb into the system.

 

Respiration In Stems

The air coming in contact with the stem is absorbed and eventually gets 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 gets diffused through the stomata. In higher plants or woody plants, the gaseous exchange is carried out by lenticels.

 

Aerobic and anaerobic respiration

Breathing can be possible in both the presence and absence of oxygen. 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.

The only cytoplasm is responsible for anaerobic respiration

Aerobic respiration requires the presence of oxygen.

Oxygen is not necessary for this form of respiration.

Aerobic respiration help in gas exchange.

Gases are not exchanged in this form of respiration.

Glucose breaks down into carbon dioxide and water.

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

All higher organisms such as mammals have this type of respiration.

Lower organisms such as bacteria and yeast use this type. In other organisms, it occurs during heavy activities

 

Differences between Respiration and Photosynthesis

Photosynthesis  

Respiration

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 is a continuous process happen day and night





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