Question

Given below are two statements regarding the root pressure theory of translocation of water in plants.
Statement (I): Under normal conditions, the sap in the xylem cells shows negative hydrostatic pressure.
Statement (II): It also shows high osmotic pressure.
In light of the above statements, choose the most appropriate answer from the options given below.

• A. Both Statement (I) and Statement (II) are correct.
• B. Both Statement (I) and Statement (II) are incorrect.
• C. Statement (I) is correct but Statement (II) is incorrect.
• D. Statement (I) is incorrect but Statement (II) is correct.

Hint:

Xylem sap is under tension during transpiration, and it is a dilute solution with low osmotic pressure.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept
These statements are objections to the root pressure theory, which needs positive pressure in the xylem.

Step 2: Statement I
Under normal conditions, transpiration pulls on the water column, so the sap is under tension. It has negative hydrostatic pressure, so Statement (I) is correct.

Step 3: Statement II
Xylem sap is a very dilute mineral solution, so its osmotic pressure is low, not high. Statement (II) is incorrect.

Final Answer:
Statement I is correct but Statement II is incorrect. \[ \boxed{\text{(C) }\text{Statement (I) is correct but Statement (II) is incorrect.}} \]