Question

The common chemical agents used as preservative solutions to improve the keeping quality of cut flowers is

• A. Silver thiosulfate
• B. Magnesium sulfate
• C. Sodium chloride
• D. Sodium hydroxide

Hint:

Silver Thiosulfate (STS) is a standard inhibitor of ethylene action in plant research and commercial floriculture.
It works because the silver ion (\( \text{Ag}^+ \)) competes with ethylene for binding to the ethylene receptors.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Cut flowers undergo rapid senescence due to physiological factors such as vascular blockage, water stress, carbohydrate depletion, and the action of the aging hormone ethylene.
To extend the vase life and maintain the aesthetic quality of cut flowers, preservative solutions are used in floriculture.

Step 2: Detailed Explanation:
Let us examine the physiological function of the correct chemical agent:
1. Ethylene-Induced Senescence: Ethylene coordinates petal abscission, wilting, and overall senescence in many cut flowers (such as carnations and orchids).
2. Silver Thiosulfate (STS) (A): STS is an effective anti-ethylene agent.
The silver ion (\( \text{Ag}^+ \)) acts as a competitive inhibitor of ethylene receptors inside plant cells.
By binding irreversibly to these receptors, \( \text{Ag}^+ \) blocks the signal transduction pathway of both endogenous and exogenous ethylene.
Thiosulfate is used as a carrier complex to make the silver ions mobile and less phytotoxic, allowing them to move through the vascular system of the stem.
Exogenous application of STS dramatically delays senescence, prevents premature petal drop, and improves the post-harvest shelf life of cut flowers.
The other options, such as Magnesium sulfate (B), Sodium chloride (C), and Sodium hydroxide (D), do not have specific anti-senescence or anti-ethylene activity.

Step 3: Final Answer:
The chemical agent used to improve the vase life of cut flowers is Silver thiosulfate, which corresponds to option (A).