Question

Identify the compounds used as germicides in vase solutions to improve quality and longevity of cut flowers
(A). Aluminium sulfate
(B). Silver nitrate
(C). 8 - Hydroxyquinoline sulfate
(D). Aminocyclopropane carboxylic acid
Choose the correct answer from the options given below:

• A. (A) and (C) only.
• B. (A), (B) and (D) only.
• C. (B), (C) and (D) only.
• D. (A), (B) and (C) only.

Hint:

To extend the vase life of cut flowers, solutions should contain a carbon source (sucrose), an acidifying agent (citric acid), and a germicide (such as 8-HQS or silver thiosulfate).

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
The post-harvest life of cut flowers is often limited by vascular blockage caused by microbial growth at the cut end of the stem.
Vase solutions contain germicides to inhibit bacteria and fungi, maintaining water uptake and extending flower longevity.

Step 2: Detailed Explanation:
- Aluminium sulfate [A]: Acts as an acidifying agent and germicide in vase solutions.
It lowers pH to around 3.5–4.5, which inhibits microbial growth and improves water uptake.
- Silver nitrate ($\text{AgNO}_3$) [B]: A powerful antibacterial agent.
Silver ions block bacterial colonization at the stem end, preventing vascular occlusion.
- 8-Hydroxyquinoline sulfate (8-HQS) [C]: A widely used germicide and chelating agent in commercial cut flower preservatives.
It suppresses bacterial growth and inhibits stomatal opening to reduce water loss.
- Aminocyclopropane carboxylic acid (ACC) [D]: The immediate biochemical precursor to ethylene.
Ethylene accelerates senescence and petal abscission, so ACC reduces cut flower longevity and is never added to vase solutions.
Therefore, Aluminium sulfate, Silver nitrate, and 8-HQS are used as germicides to preserve cut flowers.

Step 3: Final Answer:
The compounds used as germicides in vase solutions are Aluminium sulfate (A), Silver nitrate (B), and 8-Hydroxyquinoline sulfate (C).