Question

Which of the following is required for wet-heat sterilization in plant tissue culture experiments?

• A. Laminar flow
• B. Filtration assembly
• C. Oven
• D. Autoclave

Hint:

Remember that "wet heat" is always more effective than "dry heat" at the same temperature because moisture significantly increases the penetration and heat transfer capability of the steam.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Sterilization is the process of eliminating all forms of microbial life, including spores. In plant tissue culture, several methods are used: dry heat, wet heat, filtration, and surface sterilization. Wet-heat sterilization relies on high-pressure steam to denature proteins and destroy cell membranes of contaminants.

Step 2: Detailed Explanation:
The Autoclave is the specialized equipment designed for wet-heat sterilization. It works on the principle of a pressure cooker; by increasing the pressure inside the chamber, the boiling point of water is raised. Under standard laboratory conditions, an autoclave operates at \(121^{\circ}\)C at 15 psi (pounds per square inch) for approximately 15 to 20 minutes. This combination of heat and moisture is highly effective at killing even the most heat-resistant bacterial endospores. It is used to sterilize culture media, glassware, and plasticware that can withstand high temperatures.
Other options serve different purposes: Laminar flow provides a sterile workspace using HEPA-filtered air but does not sterilize materials. Filtration assemblies are used for "cold sterilization" of heat-labile liquids (like hormones or vitamins) that would decompose in an autoclave. A Hot air oven is used for dry-heat sterilization, typically at \(160^{\circ}\)C to \(180^{\circ}\)C for several hours, suitable for glassware but not for liquids.

Step 3: Final Answer:
The Autoclave is the essential instrument for wet-heat sterilization in laboratory settings.