Question: 113: The phenomenon by which the undividing parenchyma cells start to divide mitotically during plant tissue culture is called as :
(1) Differentiation
(2) Dedifferentiation
(3) Redifferentiation
(4) Secondary growth
Answer: Option (2)
Explanation:
In plant tissue culture, mature parenchyma cells normally do not divide and are considered differentiated cells.
When these mature parenchyma cells regain the ability to divide mitotically, the process is known as dedifferentiation.
During dedifferentiation, specialized cells lose their specific structural and functional characteristics and become meristematic in nature.
This process leads to the formation of callus, which is a mass of actively dividing undifferentiated cells.
Differentiation refers to the process by which meristematic cells become specialized.
Redifferentiation occurs when dedifferentiated cells again specialize into different cell types.
Secondary growth involves increase in girth of plant organs and is not related to tissue culture.
Hence, the correct answer is dedifferentiation.