Leucoplasts

Leucoplasts

What is a Leucoplast?

Leucoplasts are colorless plastids found in non photosynthetic tissues of plants. They serve various functions, for example storage of starch, lipids, or proteins. A leucoplast may also perform biosynthetic functions such as the synthesis of fatty acids, amino acids, and various other compounds. Although they vary in shape, a leucoplast is usually much smaller than a chloroplast.

Proteinoplasts

Proteinoplasts contain crystalline bodies of protein and are often the sites of enzyme activity involving those proteins. Proteinoplasts are found in many seeds, such as brazil nuts and peanuts. Proteinoplasts were identified in the 1960s and 1970s as having large protein inclusions that are visible with both light microscopes and electron microscopes. It is uncertain whether they are in specialist protein storage organelles as amyloplasts are starch storage plastids and elaioplasts are oil storage plastids. A book written in 2007 noted that no scientific research had been published in the previous 25 years on proteinoplasts, and that we know very little about them.

Statoliths: sensing gravity

In the root cap there is a special subset of cells, called statocytes. Inside the statocyte cells, some specialized amyloplasts are involved in the perception of gravity by the plant (gravitropism). They are also found in the endodermic layer of the inflorescence stem.

Elaioplasts are a type of leucoplast that is specialized for the storage of lipids in plants. Elaioplasts house oil body deposits as rounded plastoglobuli, which are essentially fat droplets. Relativity little is known about Elaioplasts, and the true extent of their functions are still being determined.

Elaioplasts

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Amyloplasts:

Amyloplasts are responsible for the synthesis and storage of starch granules, through the polymerization of glucose. Amyloplasts also convert this starch back into sugar when the plant needs energy. Large numbers of amyloplasts can be found in fruit and in underground storage tissues of some plants, such as in potato tubers. Amyloplasts are starch grains.

Amyloplasts and chloroplasts are closely related,

and amyloplasts can turn into chloroplasts; this

is for instance observed when potato tubers are

exposed to light and turn green.

Randi Block

Why Are Leucoplasts Important?

- They are sites for enzyme activity involving proteins.

- They synthesize Heme, which is used in Hemoglobin

-They synthesize fatty acids

- They store and produce the sugars, and complex starches that we eat each day, and use for energy.

- They control the way that plants grow

- They can synthesize almost all of the 20 amino acids

No other organelle can do what I do!

Leucoplasts in Potato Cells

Leucoplasts can be seen quite easily in potatoes because amyloplasts (a type of leucoplast) store the starch that makes up potatoes.

Plastids are the site of manufacture and storage of important chemical compounds used by the cell. Plastids are also a specialized class of cellular organelles that carry their own genome and have formed a symbiotic relationship with the eukaryotic cell.