Question

Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : Transpiration plays an important role in the upward movement of water. Reason (R) : Water continues to rise upward to maintain the turgidty of the cells for various metabolic processes even in the absence of the transpiration. In the light of the above statements, choose the most appropriate answer from the options given below :

• A. Both (A) and (R) are correct and (R) is the correct explanation of (A)
• B. Both (A) and (R) are correct but (R) is not the correct explanation of (A)
• C. (A) is correct but (R) is not correct
• D. (A) is not correct but (R) is correct

Hint:

Remember that transpiration acts like a drinking straw; if you stop sucking at the top (no transpiration), the liquid column stops rising up the straw.

Answer 1

The Correct Option is C

Step 1: Concept
The upward movement of water and dissolved minerals from the roots to the upper parts of a plant body is driven primarily by a continuous pulling force known as transpiration pull.

Step 2: Meaning
Transpiration is the loss of water vapor from the aerial surfaces of a plant. This evaporative process creates a negative hydrostatic pressure gradient that draws water upward through the xylem tissue.

Step 3: Analysis
Assertion (A) is completely correct because transpiration pull is the primary force responsible for the bulk upward ascent of sap in tall trees. Reason (R) states that water continues to rise upward even in the complete absence of transpiration; this is incorrect because without the cohesive tension created by transpiration, large scale upward movement cannot be sustained, causing plants to wilt during extended periods of zero transpiration.

Step 4: Conclusion
Since Assertion (A) is true but Reason (R) is false, the most appropriate choice is option (3), which corresponds to structural option (C). Final Answer: (C)