Question

Given below are two statements, one is labelled as Assertion (A) and other one labelled as Reason (R).
Assertion (A) : Potassium accelerates the translocation of photosynthates from leave to tubers, increase higher root yield in sweet potato.
Reason (R) : The quality characters like starch and protein contents decreases with increase in potassium in sweet potato.
In 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:

Because tuber crops like sweet potato, cassava, and potato have exceptionally high potassium requirements to support starch translocation, they are often referred to as 'potassiophilic' crops.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Potassium (K) is an essential macronutrient known as the "quality element" in crop nutrition.
It plays a major role in enzyme activation, stomatal regulation, and the synthesis and translocation of carbohydrates.

Step 2: Detailed Explanation:
Let us evaluate both statements individually:
- Assertion (A): Sweet potato is a tuberous root crop.
Potassium plays a key role in activating ATPase enzymes, which provide the energy needed to load sucrose into phloem vessels.
This accelerates the translocation of photosynthates (sugars and starches) from the leaves (source) to the underground tuberous roots (sink), directly increasing root size and yield.
Therefore, Assertion (A) is correct.
- Reason (R): This statement asserts that quality characters like starch and protein content decrease with increased potassium application.
This is incorrect. Because potassium directly drives starch synthesis and enzyme activation, applying potassium actually increases the starch and protein content of sweet potato tubers, improving their nutritional and culinary quality.
Therefore, Reason (R) is incorrect.
Thus, (A) is correct, but (R) is incorrect.

Step 3: Final Answer:
The correct option is (C) as (A) is correct but (R) is not correct.