Plastids are special cell organelles found in plant cells which are centers of specialized metabolic activities.
Types of Plastids
Plastids are classified into 3 types.
The Chromoplasts contain pigments. Chromoplasts is the basic element which decide the colour in flowering plants. They are further divided based on the presence of colour.
Pheoplasts contain the pigment fucoxanthin, which is brown in colour. Brown algae, diatoms and dinoflagellates consist of Pheoplasts.
Rhodoplasts contain the red pigment called phycoerythrin. The cells of red algae contain Rhodoplasts.
Leucoplasts are the plastids without colour pigments. Leucoplasts in plants are useful for the storage of starch, oil and proteins.
Chloroplast contains the green pigment chlorophyll a and b. Organisms like Green algae and plants contain Chloroplast.
One form of plastids can be converted into another form .