In tissue culture experiments, leaf mesophyll cells are put in a culture medium to form callus. This phenomenon may be called as :
Differentiation
Dedifferentiation
Development
Senescence
The correct option is Option 2) Dedifferentiation. In tissue culture experiments, when leaf mesophyll cells are placed in a culture medium and start to divide and proliferate, they undergo dedifferentiation. Dedifferentiation refers to the process where specialized cells revert to a less specialized or undifferentiated state. In the case of tissue culture, dedifferentiation allows the cells to lose their specialized characteristics and regain their ability to divide and form callus, which is an undifferentiated mass of cells. This process provides an opportunity for researchers to manipulate and regenerate new plants from these dedifferentiated cells.