Question

Given below are two statements, one is labelled as Assertion (A) and other one labelled as Reason (R).
Assertion (A) : Over watering is very harmful to chrysanthemum plants, hence proper drainage in the field and pots should be maintained for commercial cultivation.
Reason (R) : Over watering causes yellowing of leaves and mortality of chrysanthemum plants due to insufficient supply of oxygen for root respiration resulting in rotting of roots.
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:

To prevent root rot in potted chrysanthemums, use a well-draining potting medium containing sand, compost, and loam in equal parts, and ensure container drainage holes remain open.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Plants require oxygen in the soil root zone for normal cellular respiration.
Waterlogging displaces air in soil pores, creating an anaerobic environment that impairs root function.

Step 2: Detailed Explanation:
- Assertion (A) is correct: Chrysanthemums are highly sensitive to waterlogging. Excess moisture promotes soil-borne pathogens and root rot, making adequate drainage essential in both field and container cultivation.
- Reason (R) is correct: Overwatering saturates soil pores, limiting the oxygen supply required for root respiration.
This oxygen deficiency causes roots to rot, which impairs nutrient uptake.
The loss of active root surface area leads to foliar yellowing (chlorosis) and eventually causes plant mortality.
Since the lack of root zone oxygen directly explains why waterlogging is harmful, Reason (R) is the correct explanation of Assertion (A).

Step 3: Final Answer:
Both (A) and (R) are correct, and (R) is the correct explanation of (A).