Study the following table showing the components of water potential in closely arrange mesophyll cells namely A, B and C
`{:("Cell","Osmotic Potential (MPa)","Pressure Potential (MPa)"),(A,-0.21,0.05),(B,-0.22,0.02),(C,-0.23,0.05):}`
Identify two of the following , which show the correct direction of water movement between two cells .
`I. ArarrB. II BrarrC `
`III.CrarrA. IV CrarrB`

Options

A. I ,II
B. II, III
C. I ,IV
D. II,IV

Answer

To solve the question, we need to calculate the water potential for each of the cells (A, B, and C) using the formula for water potential (Ψw):

\[ \Psi_w = \Psi_p + \Psi_s \]

Where:
- Ψw = Water potential
- Ψp = Pressure potential
- Ψs = Osmotic potential

### Step 1: Calculate Water Potential for Cell A
Given:
- Osmotic Potential (Ψs) for A = -0.21 MPa
- Pressure Potential (Ψp) for A = 0.05 MPa

Using the formula:
\[ \Psi_w(A) = Ψp + Ψs = 0.05 - 0.21 \]
\[ \Psi_w(A) = -0.16 \, \text{MPa} \]

### Step 2: Calculate Water Potential for Cell B
Given:
- Osmotic Potential (Ψs) for B = -0.22 MPa
- Pressure Potential (Ψp) for B = 0.02 MPa

Using the formula:
\[ \Psi_w(B) = Ψp + Ψs = 0.02 - 0.22 \]
\[ \Psi_w(B) = -0.20 \, \text{MPa} \]

### Step 3: Calculate Water Potential for Cell C
Given:
- Osmotic Potential (Ψs) for C = -0.23 MPa
- Pressure Potential (Ψp) for C = 0.05 MPa

Using the formula:
\[ \Psi_w(C) = Ψp + Ψs = 0.05 - 0.23 \]
\[ \Psi_w(C) = -0.18 \, \text{MPa} \]

### Step 4: Compare Water Potentials
Now we have the water potentials:
- Ψw(A) = -0.16 MPa
- Ψw(B) = -0.20 MPa
- Ψw(C) = -0.18 MPa

Water moves from regions of higher water potential to lower water potential. Thus, we can determine the direction of water movement:
- A (-0.16) to B (-0.20): Water moves from A to B.
- C (-0.18) to B (-0.20): Water moves from C to B.

### Step 5: Identify Correct Directions of Water Movement
Now we can analyze the given options:
- I. A → B (Correct)
- II. B → C (Incorrect, as water moves from higher to lower potential)
- III. C → A (Incorrect, as water moves from higher to lower potential)
- IV. C → B (Correct)

### Conclusion
The correct directions of water movement are:
- I. A → B
- IV. C → B