Question

Arrange the root hair, cortical cell and mesophyll cell in ascending order on the basis 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

Water flows from a region of lower DPD (diffusion pressure deficit) to higher DPD. When roots absorb water, it moves from root hair cells to the root cortex cells and then passes on through xylem to the leaf mesophyll cells from where it leaves the plant body and goes to the atmosphere in form of water vapour. Hence, root hair cells will have lowest DPD, root cortical cells will have next higher DPD and leaf mesophyll cells will have highest DPD in the plant body, which will be less as compared to the atmosphere.

Thus, the correct answer is option A.