Question

Are the different types of plastids interchangeable? If yes, give examples where they are getting converted from one type to another.

Answer 1

Introduction to plastids

Plastids are of three basic types:

• Leucoplast (colourless plastid)
• Chromoplast (coloured plastids like red, yellow, orange etc.)
• Chloroplast (green colored plastid)

Depending on the circumstances, one type of plastid may get converted into another type.


Chloroplast changing to chromoplast

When the proportion of carotenoid pigment increases and loss of chlorophyll occurs, the chloroplasts get converted to chromoplast. This happens during ripening of fruits like tomatoes or chillies when they turn red from their unripe green color.


Leucoplast changing to chloroplast

In potatoes, leucoplasts are responsible for storage of starch. Exposure of a part of the potato tuber to sunlight causes it to acquire green colour. This happens as the leucoplasts get changed into chloroplasts.


Leucoplast changing to chromoplast

Leucoplast can also get converted into chromoplasts. For example, the development of some pigments like carotenoids in carrot occurs due to replacement of leucoplasts