In plant tissue culture medium, Agar is a gelling agent This about agar is incorrect

The correct option is "does not use in micropropagation work".

Let us understand why this statement about agar is incorrect by analyzing its role and properties in plant tissue culture:
1. What is Agar? Agar is a gelatinous substance obtained from red algae (primarily from the genera Gelidium and Gracilaria). It is widely used as a solidifying or gelling agent in culture media to provide a stable support matrix for growing plant tissues.
2. Stability and Reactivity: Agar is highly favored because it remains stable at incubation temperatures (typically 25 °C for plant tissue culture) and does not react chemically with the media constituents (nutrients, vitamins, and hormones), ensuring that the nutrient composition remains unaltered.
3. Resistance to Enzymatic Degradation: Plants do not produce enzymes capable of digesting agar, which allows the gel structure to remain intact throughout the culture period.
4. Role in Micropropagation: Micropropagation is a technique of cloning plants in vitro on a large scale. Solid or semi-solid media containing agar are standard in micropropagation to hold the explants (plant tissues) in place, allowing them to absorb nutrients and grow shoots and roots. Therefore, saying that agar "does not use in micropropagation work" is factually incorrect because it is one of the most commonly used gelling agents in micropropagation.