Question

The osmotic potential and pressure potential of three cells (A,B,C) located in different parts of an actively transpiring plant are given below.

Cell	Osmotic potential (mpa)	Pressure potential (mpa)
A	-0.87	0.44
B	-0.92	0.34
C	-0.68	0.27

Identify these three cells as root hair, root cortical and leaf mesophyll cells respectively.

• A. A, B, C
• B. A, C, B
• C. C, A, B
• D. B, C, A

Answer 1

Answer: (C)

C, A, B

Water potential is calculated by the sum of osmotic potential and pressure potential. Further water moves from higher water potential to lower water potential. The calculated values of water potential for three cells A, B and C are -0.43, -0.58 and -0.41. Thus water will flow from C to A to B. This indicates that cell C must be root hair, A must be root cortex and B must be leaf mesophyll.

So, the correct answer is 'C, A, B'