Do Plant Cells Have Lysosomes?3 Facts You should Know


In this post, you will find the information about do plant cells have lysosomes, and detailed facts around it.

Plant cells do not have lysosomes because they have cell wall which act as a barrier and does not allow the entry of unwanted substances. If somehow there is unwanted substance gets into the plant cell, the function of lysosomes will be carried out by vacuoles or sphaerosomes.

Do plant cells have lysosomes?

Plant cell do not posses lysosomes, the lysosomal activity is carried out by sphaerosomes, aleurone grains and vacuoles. Like few exceptions were there, some plants have lysosomes but they are very uncommon. The main reason for plant cell not having lysosomes is that, it contains cell wall which restricts the entry of unwanted substances inside the cell.

However, the presence of lysosomes in the plant cell are not necessary because cell wall act as a main barrier for unwanted substances in plant cell. And if somehow, unwanted substance get into the cell, vacuoles and sphaerosomes perform the function of lysosomes.

Lysosomes are the main component or organelle of the eukaryotic cell. Their main occurrence is found in protistan, protozoans and animal cells with the exception of erythrocytes. Lysosomes are also reported to found in some fungi, seeds, root tips etc.

Why plant cells don’t have lysosomes?

Lysosomal activity is carried out by sphaerosomes, aleurone grains and vacuoles in plant cell. However, the main reason for plant cell not having lysosomes is that, it contains cell wall which restricts the entry of unwanted substances inside the cell. Plant cell do not require lysosomes because they have tough cell wall that blocks the entry of unwanted substances.

A cell may contain number of lysosomes depending upon the phagocytic activity. Like leucocytes have phagocytic activity, the number of lysosomes is very high in them. The size generally range from 0.2-0.8μm in diameter. Lysosomes are resistant to enzymes because their surrounding membrane protects the lysosomes due to high degree of glycosylation of its protein and lipids.

Inside the lysosome, granular fluid is present along with the digestive enzymes. There are fifty hydrolytic enzymes are present inside the lysosomes. The enzymes can act on almost every type of substances except some carbohydrates. The important enzymes present in the lysosomes are : proteases, nucleases, lipases, phosphatases, glycosidases, lysozyme and sulphatases.

What do plants have instead of lysosomes?

The lysosomal activity is carried out by sphaerosomes, aleurone grains and vacuoles in plant cell. However, there are few exceptions in plants that contain lysosomes. The main reason for plant cell not having lysosomes is that, it contains cell wall which restricts the entry of unwanted substances inside the cell.

However, the presence of lysosomes in the plant cell are not necessary because cell wall act as a main barrier for unwanted substances in plant cell. And if somehow, unwanted substance get into the cell, vacuoles and sphaerosomes perform the function of lysosomes.

Why lysosomes are called digestive bags?

The reason for calling them digestive bags is that they contain large number of digestive enzymes. Only a thin membrane separates the hydrolases from the cytoplasm. The membrane do not break normally. The materials are acted upon by lysosomal enzymes that are enclosed in a membrane and the complex fuses with the lysosome so that lysosomal hydrolases do not spill out in the cytoplasm.

do plant cells have lysosomes
1.Material entering a food vacuole through the plasma membrane, a process known as endocytosis. 2. lysosome with an active hydrolytic enzyme comes 3. lysosome fusing with the food vacuole and hydrolytic enzymes entering the food vacuole.4. hydrolytic enzymes digest the food particles from Wikipedia

Lysosome mainly takes part in the intracellular digestion. Digestion of microbes usually takes place through phagocytosis with the help of enzyme lysozyme present in the lysosomes.

What are the components present in the lysosomes?

The membrane of lysosomes contains cortisol, cholesterol, heparin, chloroquine, antihistamine. These all components together called membrane stabilizers. Chloroquine is a stabilizer but its main function is to maintain the lysosomal pH. It is basic in nature and thus increases the pH and lowers the activity of contained enzymes.

If there is excess of liposoluble vitamins (K, E, D and  A), hormones, bile salts, ubiquinone, X rays and UV rays make the lysosome membrane weak and fragile. The substances that make the membrane fragile are called membrane labilisers.

Biogenesis of Lysosomes

Lysosomes are formed from Golgi apparatus. During the function, lysosomes changes their morphological and physiological states. There are two forms of lysosomes, primary and secondary. Primary lysosomes are true lysosomes. They are formed from the maturing face of Golgi body and spreads in the  cytoplasm. Lysosomes contain hydrolases enzymes in the form of minute granules.

Secondary lysosomes are of three kinds, heterophagosomes, autophagosomes and residual bodies. Secondary lysosomes are formed when primary lysosomes are combined with pinosomes and phagosomes. Phagosomes helps in bringing out the food materials from outside to inside the cell. Two or more heterophagosomes are fused together to form big digestive vacuole, these digestive vacuoles digests the big food complex materials with the help of hydrolytic enzymes.

What is autophagy?

Autophagy is the digestion of unwanted organelle that become degenerated during alternative development. The unwanted cell organelles are enclosed in smooth membrane or isolation envelope that forms isolation body. Few to several lysosomes are combined with isolation body to form autophagic vacuole. Digestion takes place with the help of acid hydrolases enzyme.

Difference between autophagy and autolysis

AutophagyAutolysis
It is the digestion of the cell organelle or reserve food material.It is the digestion of the whole cell.
Formation of isolation body takes place. An isolation body is not produced.
Few to several lysosomes are combined with isolation body to form autophagic vacuole.No such vacuole like structures are formed.
Lysosomal membrane does not break.Lysosomal membrane breaks down.
Enzymes remain restricted inside the autophagic vacuole.Enzymes can pass out through membrane into the cytoplasm.
Autophagy comes into play when there is not enough food reserve or starvation of cell.It is resorted for the removal of whole cells and tissues.
Autophagy provides nourishment during starvation.Whole cell is digested, no nourishment is provided.
An example is, autophagy reabsorbs the useless structures during metamorphosis.It occurs in damaged cell and reabsorption of of tadpole tail during metamorphosis.

Functions of Lysosomes.

  • Intracellular digestion or heterotrophy occurs through phagosomes and digested with the help of lysosomes.
  • Lysosomes also helps in osteogenesis or extracellular digestion that passes out the hydrolases enzyme through ephagy which helps in digestion of cartilage matrix and paves the way for deposition of matrix of bone.
  • During starvation, lysosomes helps in break down of proteins and fat molecules. In more severe conditions, lysosomes also breakdown the cell organelle to get nourishment.
  • They are highly present in the leucocytes and macrophages for the digestion of bacteria and other unwanted substances.
  • Lysosomes play crucial role in the initiation of mitosis.
  • Lysosomes dissolves the stored food reserve in seeds for germination.

Define Ephagy

Residual body helps in passing out the undigested substances in contact with plasmalemma by Ephagy and Exocytosis. In liver cell and muscle cells, residual bodies do not throw the substances outside the cell. Instead they load the cells and bring about ageing. Lipofuscin granules are derived from residual bodies that are present in nerve cells.

Conclusion

Plant cell do not posses lysosomes, the lysosomal activity is carried out by sphaerosomes, aleurone grains and vacuoles. the presence of lysosomes in the plant cell are not necessary because cell wall act as a main barrier for unwanted substances in plant cell. And if somehow, unwanted substance get into the cell, vacuoles and sphaerosomes perform the function of lysosomes.

Saif Ali

Hi, I am Saif Ali. I obtained my Master's degree in Microbiology and have one year of research experience in water microbiology from  National Institute of Hydrology, Roorkee. Antibiotic resistant microorganisms and soil bacteria, particularly PGPR, are my areas of interest and expertise. Currently, I'm focused on developing antibiotic alternatives. I'm always trying to discover new things from my surroundings.  My goal is to provide readers with easy-to-understand microbiology articles. If you have a bug, treat it with caution and avoid using antibiotics to combat SUPERBUGS. Let's connect via LinkedIn.

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