Question

Given diagram illustrates the changes that occur when a plant cell takes up water. Identify L, M and N and select the incorrect statement regarding the given diagram.

• A. N is the diffusion pressure deficit which becomes zero when L and M are equal in magnitude
• B. In a flaccid cell, value of N becomes equal to that of L
• C. M represents osmotic pressure, which increases when a flaccid cells takes up water
• D. L represents solute potential, which decreases with the increase in turgidity of the cell

Answer 1

The correct option is C M represents osmotic pressure, which increases when a flaccid cells takes up water

Given diagram illustrates the changes that occur when a flaccid plant cell takes up water. L represents osmotic pressure (OP) or solute potential $\left({\psi }_w\right)$, M represent turgor pressure (TP) or pressure potential$\left({\psi }_p\right)$ and N represents diffusion pressure deficit (DPD) or water potential $\left({\psi }_w\right)$.
In a flaccid cell, TP is zero, therefore, DPD$=$OP$-0=$OP. When a flaccid cell is placed in water, it takes up water due to endosmosis, OP of the cell starts decreasing while TP starts increasing. In fully turgid condition, OP and TP become equal so that DPD becomes zero.

So,M represents osmotic pressure, which increases when a flaccid cells takes up water