Question

Given below are two statements, one is labelled as Assertion (A) and other one labelled as Reason (R).
Assertion (A): Over watering of chrysanthemum plants is very harmful for their proper growth and development.
Reason (R): Over watering cause yellowing of leaves and mortality of plants due to 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:

Chrysanthemums are highly susceptible to root rot caused by wet, poorly drained soils. Always ensure a well-drained growing medium to avoid waterlogging and root decay.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Water management is a critical aspect of cultivating greenhouse and field ornamentals like Chrysanthemum (Chrysanthemum morifolium).
While plants require adequate moisture for cellular turgor, nutrient uptake, and photosynthesis, excessive soil moisture (waterlogging) creates an anaerobic environment around the roots.
This oxygen deprivation impairs root respiration and leaves the plant susceptible to soil-borne pathogens.

Step 2: Detailed Explanation:
Assertion (A) is correct:
Chrysanthemums have a shallow, fibrous root system that is highly sensitive to waterlogged conditions.
Over-watering or poor soil drainage is harmful to their growth, leading to stunted plants, poor flower quality, and eventual plant death.
Thus, Assertion (A) is correct.
Reason (R) is correct:
When the soil is saturated with water, the air spaces between soil particles are filled with water, depriving the roots of oxygen.
This anaerobic condition prevents the roots from carrying out normal respiration, leading to root rot (typically caused by fungal pathogens like Pythium, Phytophthora, or Rhizoctonia).
As the root system decays, it can no longer absorb water and nutrients.
This root damage manifests above-ground as interveinal yellowing (chlorosis) of the leaves, wilting, and eventually the death (mortality) of the plant.
Therefore, Reason (R) is not only correct but also explains why over-watering is harmful to chrysanthemums.

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