Question

The correct ascending sequence with respect to their water potential is

(a) $\pi =-0.8\text{MPa},P=+0.4\text{MPa}$
(b) $\pi =-1.0\text{MPa},P=+0.5\text{MPa}$
(c) $\pi =-0.9\text{MPa},P=+0.2\text{MPa}$
(d) $\pi =-0.3\text{MPa},P=+0.2\text{MPa}$

• A. a, b, c, d
• B. c, b, a, d
• C. c, a, b, d
• D. c, d, b, a

Answer 1

The correct option is B c, b, a, d

Water potential is the potential energy of water per unit volume. It is the measure of free energy or potential energy of water in a system relative to the free energy of pure water. Water potential is denoted by the Greek letter ψ (psi) and is measured in the terms of bars. Water potential can be measured using the formula, ψ = ψπ + ψp where ψπ = Solute Potential or Osmotic Potential and ψp = Pressure Potential or Turgor Potential.

From the question it is given,

(a) : ψπ = -0.8

ψp = 0.4

ψ = -0.8 + 0.4 = -0.4.

(b) : ψπ = -1.0

ψp = 0.5

ψ = -1.0 + 0.5 = -0.5.

(c) : ψπ = -0.9

ψp = 0.2

ψ = -0.9 + 0.2 = -0.7.

(d) : ψπ = -0.3

ψp = 0.2

ψ = -0.3 + 0.2 = -0.1.

Therefore, the correct ascending sequence with respect to their water potential is -0.7, -0.5, -0.4 and -0.1 i.e, c, b, a, and d.

So, the correct answer is option B.