Question

You are given three cells, a root hair, a cell of the inner cortical layer and a cell of the mesophyll. Arrange them in ascending order of DPD.

• A. Root hair < Cortical cell < Mesophyll
• B. Cortical cell < Mesophyll < Root hair
• C. Mesophyll < Root hair < Cortical cell
• D. Root hair < Mesophyll < Cortical cell

Answer 1

The correct option is A Root hair < Cortical cell < Mesophyll

The diffusion of water takes place from the region of lower DPD to the region of higher DPD in the process of osmosis. When water is absorbed in plants, it passes from root hair to the cortical region. Then it passes through the vascular tissue and finally reaches the leaf mesophyll. Thus, the DPD will be lowest in the root hair and highest in the leaf mesophyll, while that of the cortical region will be intermediate. Hence, the correct order is:
Root hair < Cortical cell < Mesophyll.