Elaioplasts

Elaioplasts are lipids storage plastids (organelle enclosed in a membrane that is present in the cells of plants, algae, and certain other eukaryotic species). Elaioplast is the leucoplast specialised in storing lipids, proteins, fats, and oil. Leucoplasts are colourless, non-photosynthetic plastids. Leucoplasts are used for the storage of fat, oil, starch, and proteins.

Leucoplasts can be categorised into three categories based on their functions:

i) Amyloplasts: Amyloplasts are double-enveloped organelles responsible for starch storage and synthesis.

ii) Proteinoplasts or Aleuroplast: Proteinoplasts are organelles that assist plants in storing the proteins required by plants. They are commonly found in seeds.

iii) Elaioplasts: Elaioplasts are responsible for storing fats and oils that the plant requires. It is found in the liverworts and seeds of monocotyledons plants. 

Functions of Elaioplasts

The elaioplasts are found mainly in the non-photosynthetic part of the plants (monocots and liverworts. Elaioplasts are also responsible for forming fatty acids, lipids, and terpenes in citrus plants. For example, exine formation during pollen development.

Since elaioplast is a type of leucoplast with amyloplasts, proteinoplasts are mainly used to store starch, proteins, and fats.

Elaioplasts are filled with oils and fatty acids and appear rounded in shape. It serves as a suitable hydrophobic sink for the buildup of carotenoids (plant pigments responsible for the colour of plants). Elaioplast is found in the layer of cells of tapetum or tapetal layer in the anther of some flowers in monocotyledons plants, embryonic leaves of seeds, seed endosperms, citrus fruits, etc.

Elaioplast plays an essential role in pollen maturation. Plastoglobuli, which are lipid-filled microcompartments, store oils in the body.

Elaioplast is used for short-term oil storage and synthesis. For long-term oil storage, oleosomes are used, generally found in seeds. Oleosomes are derived from the rough endoplasmic reticulum. 

Elioplasts, like all other plastids, reproduce by binary fission, which happens independently of the division of the parent cell, a trait that suggests that they are descended from bacteria, particularly cyanobacteria (blue-green algae), as their ancestors. As a consequence of this binary fission, which occurs just before cytokinesis (the stage of binary fission in which the cytoplasm of the parent cell is split into two), the products are transported to the daughter cells as a component of the cytoplasm of the daughter cells.

The plastome, which is a plastid genome, is found in the elaioplast. As a result, elaioplasts are capable of interconversion with other forms of plastids. Elaioplasts are much smaller in size as compared to chloroplasts.

Functions of Amyloplast 

Amyloplast is a specialised storage leucoplast founded in the storage tissues and roots. Amyloplasts store and synthesise starch through the polymerization of glucose in plants. Starch synthesis by amyloplast depends on carbon transportation from the cytosol (liquid medium inside the cell).

Amyloplasts have the ability to respond to gravity, and they assist the root in growing downward. Due to its close relationship to the chloroplast (a plastid that contains chlorophyll and is responsible for photosynthesis), amyloplast may convert into the chloroplast, such as when a potato tuber is exposed to light and becomes green. Amyloplast may be found in subterranean stems as well as cereal grains such as rice and wheat. Amyloplasts are also capable of creating a short-lived starch substance known as transient starch. At night, when photosynthesis is not taking place, this type of starch is temporarily stored in chloroplasts, where it will be broken down and used for energy production.

Functions of Aleuroplast

Aleuroplast is also known as Proteinoplasts. It is a protein specialised leucoplast found in the maze, brazil nuts, and various plant seeds. It contains the crystalline bodies of protein. Since aleuroplast has the crystalline bodies of proteins, these bodies act as activity sites for the enzyme involving these proteins. They also participate in amino acids synthesis.

The aleuroplast has fewer thylakoids (compartments inside chloroplasts and cyanobacteria that are membrane-bound. They serve as the location of the photosynthetic processes that are light-dependent).  Aleuroplasts are specialised in producing and storing proteins. Aleuroplasts are smaller in size compared to the chloroplast.

Difference between elaioplast, amyloplast, and aleuroplast

Conclusion 

 The primary function of the elaioplasts is the storage and metabolism of lipids. Elaioplasts are colourless since they belong to leucoplast, which lacks pigments. Elaioplasts, aleuroplast and amyloplast are the types of leucoplast, which is a type of plastid. The functions of the elaioplasts, aleuroplast and amyloplast are explained in detail with examples of plants containing them. The difference between all the leucoplasts is explained in detail.