"Plastid"

Introduction:

Plastids are ovoid, plate-shaped, ribbon-shaped, or stellate-shaped organisms scattered around the nucleus within the cytoplasm. In 1883, Schimper first observed green-colored plastids in plant cells and named their chloroplasts. Later other plastids were discovered.

Classification of Plastids:

Plastids are mainly of two types namely- 

A) Leucoplastids and 

B) Chromatoplastids.

A brief description of the location, color, and function of different types of plastids is as follows:

A) Leucoplastids: Leucoplastids are present in the cells of the parts of the plant body which are deprived of sunlight. They are colorless plastids. But under the influence of sunlight, their color changes and transforms into chromoplast or chloroplast.

Types: According to the shape of the food stored, leucoplasts are divided into three types, namely-

(1) Amyloplast: It is a leucoplastid storing food like sugar or starch.

(2) Aleuroplast: It is a protein or non-meat storage leucoplastid.

(3) Eleoplast: It is a leucoplastid storing food like fat or oil.

Function: The main function of leucoplast is to make food from carbohydrates and store food.

(B) Chromatoplastid: The pigmented plastid is called a chromatoplastid. Chromatoplastid contributes to the color diversity of different plant organs. 

Chromatoplastids are of two types, viz.- (C) Chromoplast and (D) Chloroplast.

(1) Chromoplast: Any color-producing plastid other than green in the plant body is called a chromoplast. Petals of flowers, the color of fruits, or any color other than green is caused by chromoplasts. Sometimes colored shoots and colored roots (radish, carrot, sweet potato) also contain chromoplasts. If necessary, chromoplast to chloroplast or chloroplast to chromoplast is converted. The red color of the young leaves of litchi, gab, Ashoka, etc. shows the presence of chromoplasts. Due to the presence of carotene and xanthophyll in the chromoplast, the color of the chromoplast can be red, yellow, orange, etc. Due to the presence of these pigments in different proportions, different color variations are seen on the petals and fruits.

Functions of Chromoplast:

1) Attracts higher-class animals including insects for pollination.

2) Dispersal of fruits and seeds attracts animals for it.

(C) Chloroplast: The plastids that produce green color in the green parts of plants especially leaves, young branches, unripe fruits, etc. are called chloroplasts. Chloroplast consists of chlorophyll-d, chlorophyll-n, carotene, and xanthophyll. But the color of chloroplast is green due to excess chlorophyll. In higher plants, the chloroplast is usually plate-like in shape.

Functions of Chloroplast:

1) Preparation of sugars with the help of carbon dioxide and water in the process of photosynthesis.

2) Binding of carbon dioxide inside the quant some.

Conclusion:

Plant and algae cells contain a wide variety of structures called plastids. They are engaged in many crucial processes like photosynthesis, starch and pigment storage, and lipid production. Plastids are believed to have started from endosymbiotic microbes and have their own DNA. Plastids are fundamental to the biochemistry of plants and microorganisms.