Do Plants Need Oxygen? Respiration & Plant Energy Explained


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Just like animals, plants also need oxygen for survival. Therefore, oxygen is an important constituent of plant life. It is required for breaking down sugars through a process called respiration (cellular respiration). 

Plants need oxygen for respiration which occurs in the cell’s mitochondria. Here, oxygen is used to break down complex sugars produced during photosynthesis, and energy, carbon dioxide, and water is produced. This process is called anaerobic respiration and the energy produced is used for plant growth.

Respiration is responsible for proper growth and maintaining the life span of plant tissues. 

Do Plants need Oxygen?

Why do plants need oxygen

Oxygen is a precious treasure both for the plants and the animals on Earth. In the absence of oxygen, plants may not be able to break the glucose molecule. 

No respiration will occur, and the plant will die.

Respiration usually occurs during the nighttime; plants consume oxygen, which plays a part in the breakdown of glucose to maintain the carbon cycle in every cell. 

During the daytime, plants use oxygen for the process of photosynthesis which is then exhaled as a by-product.

As a result, plants do not use oxygen during the daytime as it is not needed to make or synthesize food. 

How Plants Use Oxygen

Where Does Oxygen Come From?

Oxygen needed for food breakdown by the plant and for animals generally comes from the oceans. 

Plants like kelp, algal plankton, and phytoplankton are responsible for producing oxygen in bulk quantities. 

According to scientists, almost 50 to 60 percent of oxygen comes directly from oceans.

Prochlorococcus, a tiny photosynthetic organism alone, produces about 20 percent oxygen in the entire biosphere.

Whereas on the other hand, the plant itself prepares oxygen during the mechanism of photosynthesis. 

That oxygen is utilized by the animals as well as by plants during nighttime for their normal functioning. 

Moreover, oxygen is also present in the atmosphere in an abundant quantity. 

Plants intake this oxygen at nighttime with the help of the special apertures or the lenticels that are generally present on the trunk of the plant body. 

During the daytime, plants cannot utilize the oxygen that comes from the ocean (by the ocean plants ) or the atmosphere. 

This is because plants are producing their oxygen as a by-product during photosynthesis.

Photosynthesis reaction:

Photosynthesis reaction

How do Plants get Oxygen?

Plants get oxygen from the air around them by intake through the stomata where it enters the plants and is used by the mitochondria in plant cells. This is called aerobic respiration. 

Respiration reaction:

Respiration

Air contains approximately 20.8% oxygen. 

Plants, like humans, plants use oxygen in the same way, for respiration. 

Respiration is a process in living organisms involving the production of energy, typically with the intake of oxygen and the release of carbon dioxide from the oxidation of complex organic compounds. 

Stomata are cell structures found on the epidermis of tree leaves that are involved in the exchange of carbon dioxide and water between plants and the atmosphere.

Plant Stomata

There are two types of respiration in plants:

Photo-Respiration

Photorespiration is where respiration takes place in the presence of light. 

Dark Respiration 

During dark respiration, carbon dioxide is released without the presence of light. 

PhotorespirationDark respiration
Photorespiration means the process of respiration which takes place where carbon dioxide is given out which is the opposite process of photosynthesis.Dark respiration is a form of respiration in which carbon dioxide is released without the presence of light.
Photorespiration is dependent on lightDark respiration is independent of light.
Photorespiration is dependent on the Calvin cycleDark respiration does depend on the Calvin cycle.
Photorespiration involves a glycolate pathway.Dark respiration involves the glycolate pathway, Krebs cycle, and terminal oxidation.
In photorespiration, one molecule of NH3 is released per molecule of CO2.In dark respiration, there is no production of NH3.
Photorespiration is an energy waste process.Dark respiration is an energy-producing process.
The temperature required for photorespiration is 25-35℃.Dark respiration is not temperature sensitive.
[Source]

The Plant Cell

Plant cells are eukaryotic cells present in green plants, photosynthetic eukaryotes of the kingdom Plantae. Their distinctive features include primary cell walls containing cellulose, hemicelluloses, and pectin [Source]

Plant Cell

Parts of the Plant Cell

Cell Membrane –

The cell membrane, also called the plasma membrane, is found in all cells and separates the interior of the cell from the outside environment.

Chloroplast –

Chloroplasts are plant cell organelles that convert light energy into relatively stable chemical energy via the photosynthetic process

Nucleus –

Stores the cell’s hereditary material, or DNA, and it coordinates the cell’s activities, which include intermediary metabolism, growth, protein synthesis, and reproduction (cell division).

Vacuole – 

Stores water and maintains turgor pressure in a plant cell. It also pushes the contents of the cell toward the cell membrane, which allows the plant cells to take in more light energy for making food through photosynthesis.

Mitochondria –

Mitochondria are the main sources of energy for each cell, and therefore for the plant as a whole.

What Plant Cell uses Oxygen

The mitochondria are the part of the plant cell that uses oxygen in the respiration process. 

The mitochondria are the powerhouse of the cell because it takes the food from photosynthesis and breaks it down in the presence of oxygen and makes energy for the plant to use. 

Different cells have different amounts of mitochondria cells present and can produce varying quantities of energy at a time depending on the oxygen supply and demand. 

How Much Oxygen Do Plants Need?

Plant Leaf under microscope showing cells

Plants need oxygen, especially at night time for respiration (gaseous exchange) or the purpose of homeostasis. 

At night time, they need an abundant supply of oxygen for their cellular activities. So it is commonly said to avoid sleeping under plants or trees at night. 

Because plants require the maximum amount of oxygen, it may be a great cause of reducing the oxygen content. 

So it may cause suffocation, and the person sleeping under the tree might collapse due to the deficiency of oxygen. 

So by this common discussion, we can easily sum up that oxygen is essential for the survival of the plants or we can assume that how much quantity of oxygen would be needed or required by the plants as well. 

Do Plant Roots Need Oxygen?

Green Plant roots in aquaponics

Yes, of course, plants require a great deal of oxygen to grow and nourish their roots properly. 

It is commonly stated that the growth of a plant’s body occurs maximum at the tips of the roots or the twigs or branches. 

So for the proper growth of the roots, sufficient amounts of oxygen would be required. 

For this purpose, plants adapt to absorb maximum oxygen from their surroundings. See how to increase dissolved oxygen in water for plants.

One of the main reasons for proper root growth is that longer roots would help the plant take in more water from an underground area of the soil. 

An evident fact that roots need oxygen is in aquaculture. When plants are grown in both aquaponic and hydroponic water, root health is crucial to plant health and is directly linked to the dissolved oxygen present in the water. 

A sufficient amount of oxygen results in healthy white roots while oxygen-deficient environments can lead to dark and rotting roots. 

The overall result is poor plant health as the roots fail to absorb nutrients from their surroundings. 

Can Plants Survive Without Oxygen?

No, plants cannot live without oxygen. They will eventually die if they do not get the required amount of oxygen, just like the animals. 

Plants feed on oxygen to carry out the process of respiration.

In the absence of oxygen, plants cannot break the molecules of glucose down.

As a result, the unbroken glucose molecules would not be able to produce the required amount of energy needed by the plant body to accomplish its daily activities. 

So the absence of energy due to the lack of oxygen would be a cause of death and decay of the plant body parts.

However, the plants will make their maximum efforts to fulfill the energy requirements by breaking some of the food molecules in the absence of oxygen. 

But this will produce the least amount of energy that would not be able to perform all of the activities of the plants. 

So the plant may collapse. It is commonly stated that plants can not live without oxygen, and it is hundred percent true. 

Further research shows that:

In the absence of oxygen, acidification occurs within the cells of the plant which are transformed into lactate and ethanol, this forms the foundation for fermentation. 

Therefore without oxygen plants will essentially ferment and die. 

Fermentation reaction:

Anaerobic Respiration

Can Plants Produce Oxygen to Sustain Themselves?

In an enclosed environment such as a terrarium, plants can live for years by recycling the profits and byproducts of photosynthesis and respiration. 

A terrarium is an enclosed ecosystem where plants and microbes live in perfect symbiosis with each other. No external gases or nutrients are added. Only light is provided from the outside. 

Even though plants produce oxygen through photosynthesis, they cannot survive without it. 

The Process of Photosynthesis

Do Plants Use More Oxygen During The Daylight or at Night?

A general observation is that plants use more oxygen at night, and the least amount of oxygen is used in the daytime. 

It is because at day time, due to the sunlight, plants carry out a process known as photosynthesis to manufacture their food. 

During the process, an excessive amount of oxygen is prepared as a by-product.

So they produce oxygen by themselves under sunlight. 

But at night, the mechanism of photosynthesis cannot occur because of the absence of sunlight, so they need oxygen in maximum concentration to carry out all of their other activities except food synthesis.

From what was discussed, plants cannot survive or live in the absence of oxygen due to many of their cellular activities that require their presence. 

Even shortage of oxygen for a limited time may also be a significant cause of the expiry of the plant. 

How do Plants Purify the Air?

Plants purify the air through photosynthesis. The plant absorbs carbon dioxide through its leaves where a chemical reaction occurs with the chlorophyll in the presence of light which produces glucose (food for plants) and oxygen which is released back into the air.

Plants clean the air within our living space by “breathing” in the air via their stomata, found on the underside of their leaves, and pores in their roots. 

Harmful compounds such as VOCs (Volatile Organic Compounds) are produced by various materials in our home and offices which are then filtered by plants which in turn releases oxygen into the air we breathe.

Does Soil Need Oxygen?

Roots

As explained above, roots need oxygen for the production of food to grow. 

In nature, most of the oxygen deficiency in plants is caused by waterlogging whereby all the pore spaces in the soil are taken up by water causing the roots to stifle which in turn stifles the entire plant. 

This results in the yellowing of leaves and plants’ leaves dropping. 

Oxygen Absorption by the roots supplies the plant with the majority of oxygen is required to survive. 

Microbes

Microbes are living organisms that live within the soil breaking down organic matter into nutrients for the plant to absorb. 

The process in which the organic matter is broken down requires energy. Microorganisms use available oxygen from the soil for respiration to create the energy needed to perform such tasks. 

Worms

Worms found in soil

Worms are larger organisms that also live in the soil and get oxygen via the process of diffusion. 

They respire by absorbing oxygen through their skin which is then carried to the areas required by a network of capillaries. 

Worms are much larger than microbes and will use up more oxygen. 

Without oxygen, these soil organisms will also suffocate and die. 

Will Plants Grow Bigger if Given More Oxygen?

Rubisco, one of the most important enzymes in photosynthesis, can bind to O2, leading to less efficient photorespiration, instead of photosynthesis.

High amounts of oxygen aren’t going to be more beneficial in plants with respect to their growth.

JayLea

JayLea has a passion for plants and has been gardening since 2015. He has valuable knowledge about gardening and houseplant care and can answer everyday practical questions that every plant owner has.

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