Controlling ethylene in vitro — which additive is used to inhibit ethylene effects during culture?

Introduction / Context:
Ethylene accumulation in closed vessels can suppress morphogenesis and induce physiological disorders in plant cultures. Various additives are used to mitigate this, either by reducing biosynthesis, adsorbing molecules, or blocking perception.

Given Data / Assumptions:

• The question seeks a culture additive that effectively inhibits ethylene's impact.
• Practical tissue culture usage prioritizes reliable suppression of ethylene responses.
• We compare organic acids, adsorbents, and silver complexes.

Concept / Approach:

Silver thiosulfate (STS) releases Ag+ that binds ethylene receptors, blocking ethylene perception and thereby neutralizing ethylene's inhibitory effects on growth and regeneration. While some chemicals (e.g., AVG or AOA) inhibit ethylene biosynthesis, STS is widely used in vitro because it robustly suppresses ethylene action. Activated charcoal can adsorb hormones and phenolics but is nonspecific and can remove beneficial compounds; organic acids do not specifically inhibit ethylene pathways.

Step-by-Step Solution:

Verification / Alternative check:

Protocols for cut flowers and micropropagation commonly use STS dips or medium supplements to reduce ethylene sensitivity and prevent abscission or vitrification.

Why Other Options Are Wrong:

Citric and succinic acids are pH/antioxidant agents; they do not target ethylene. Activated charcoal is nonspecific and can remove PGRs. Cobalt salts can affect ACC oxidase but are less commonly used due to toxicity and inconsistency in culture.

Common Pitfalls:

Equating “inhibits ethylene biosynthesis” with “inhibits ethylene effects.” In practice, STS is chosen to suppress ethylene action reliably in vitro.

Final Answer:

Silver thiosulfate (STS)