Peroxisomes are one of the most important parts of a cell. These are found in all eukaryotic cells, be they small unicellular organisms or multicellular ones. The single membrane-enclosed organelles are also called microbodies.
Now you might be asking, do these cells of plants have peroxisomes? The answer is yes.
If you have noticed the small vesicles floating around the plant cell in the cytoplasm, they are the peroxisomes. Their diameter ranges from 0.1 to 1 micrometer. Despite their small size compared to the size of the entire cell, they’re a major part.
The reason they are named peroxisomes is that they produce hydrogen peroxide. It also has enzymes for the pentose phosphate shunt.
Are Peroxisomes Present in the Plant Cells?
The answer is yes, plant cells have peroxisomes—and it is one of the most crucial parts of the plant cell.
They act to store Beta-oxidation fatty acid in the plant cells. Besides, they are also responsible for the production of two phytohormones, namely Indole-3-acetic acid or IAA and Jasmonic Acid or JA. These conjuncts with mitochondria and chloroplasts to boost their functions.
What Do They Do in Plant Cells?
Since it is one of the major parts of the plant cell, it has many functions to keep the cell robust and working at its best. Their primary role is to break down organic molecules inside of the cell by oxidation process to produce hydrogen peroxide.
Hydrogen peroxide or H2O2 is then converted into water and oxygen. The peroxisome encloses about 50 different enzymes inside itself. None of it has any contact with the cytoplasm as it is isolated by the lipid bilayer single membrane.
Lipid catabolism takes place by the enzymes of the peroxisome. It basically means the long-chain fatty acid is broken down by the oxidation process. The fatty acid is broken down in the chemical Acetyl Coenzyme A (CoA), which is responsible for the production of a large amount of metabolic energy.
There is also another type of enzyme that is produced by the peroxisome which is responsible for the breaking down of Hydrogen peroxide or H2O2. Peroxisomes are also responsible for the production of phospholipids in the cell.
Are they necessary for plant cell function?
The peroxisome, just like most other major—or even minor organelles in the cell, is very important for the cell to function properly. This, in turn, allows the entire plant to grow by creating a fully functioning system.
For the fixation of carbon into sugar, carbon dioxide or CO2 is needed. But Chloroplast cannot produce Co2 directly. Instead, it produces Glycolate. And peroxisome comes into play here.
This Glycolate is passed through peroxisome for the production of glyoxylate. The Glyoxylate is again converted into Glycine in the peroxisome. Lastly, this Glycine is turned into Serine, and Co2 is produced in this process.
In the presence of sunlight, photorespiration takes place. And that takes place with the help of peroxisomes as well.
Peroxisome produces catalase, which again helps in breaking down the H2O2, which is produced during the conversion of Glycolate into Glyoxylate. A high concentration of H2O2 can be really harmful to the cell, causing an imbalance in the entire system.
That is why peroxisome is a must for the conversion of Glycolate into Glyoxylate, because, without catalase—which is produced only in the peroxisome, the H2O2 will end up damaging the cell. This is the detoxification step of the peroxisome in plant cells.
How do peroxisomes benefit plants?
If the plant cells are benefitted from the presence of peroxisomes in themselves—it automatically means that the entire plant is being benefitted. And plants are hugely benefitted from the existence of these organelles.
Due to allowing all the processes, including Beta-oxidation, helping in the production of Co2, photorespiration in leaves, and so on, glycolates play a significant role in ensuring that the plant is growing and functioning normally.
IAA is responsible for the growth regulation of the plant and the development of the cell. It is responsible for the proper division of cells, differentiation of tissue, and so on. All these make sure the plant is strong and grown. JA is also a growth-regulating substance in the plant’s body.
Conversion of Glycolate and ultimately producing Co2 by the mitochondria takes the help of peroxisomes. And this is one of the most important functions of the peroxisomes. It boosts the metabolism of the plants helping them to grow and fight anything coming in their way to growth.
In higher plants, photorespiration is also a very important process allowing it to respire. This process is also known as oxidative photosynthesis.
Basically, the role of peroxisomes in a plant body is immense. Without the metabolism provided by the peroxisome, it will be impossible for the plant to fight back against anything, and eventually, it will wither away.
How do plant cells compare to other cell types in terms of peroxisome presence and function?
Peroxisomes are not exclusive to plant cells. As mentioned above, these organelles are found in all eukaryotic cells, be it animal cells, plant cells, or the cell of a fungus. But of course, it does not function exactly the same in all cells.
When it comes to planting cells, the function of peroxisome mainly lies in providing a solid metabolic system. And it is done by the conversion of carbon into sugar and providing a proper energy source for the plants to live off of. This is vital for the health of the plant and its parts.
On the other hand, the functions are very different when it comes to animal cells. Here, they work also work in breaking down cholesterol and bile acids helping in the digestion of food.
They also partake in the synthesis of lipids which are used to make myelin. Also, the reason our body is able to handle ethanol is because of peroxisome. Lastly, peroxisomes break down purines to uric acid in the animal body.
Plant cells surely have peroxisomes. And not only that, it is one of the most important parts of the entire cell—keeping balance in the entire body of the plant. Without the proper functioning of the peroxisome, the plant will have a poor metabolic system and eventually die.