Question

Arrange the following basal media used in tissue culture based on its salt strength as Low $<$ Medium $<$ High

• A. MS Medium $<$ Gamborg's Medium $<$ Knop's Medium
• B. Gamborg's Medium $<$ MS Medium $<$ Knop's Medium
• C. MS Medium $<$ Knop's Medium $>$ Gamborg's Medium
• D. Knop's Medium $<$ Gamborg's Medium $<$ MS Medium

Hint:

MS Medium is renowned for its very high salt concentration (especially nitrogen sources), while Knop's is a historic, dilute formulation. Remembering these two extremes helps you easily identify the correct sequence.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Basal media are nutrient mixtures containing inorganic salts, vitamins, and carbon sources used to sustain plant tissue growth in vitro.
Different media formulations vary significantly in their total mineral concentration, commonly referred to as salt strength.

Step 2: Detailed Explanation:
Let us evaluate the inorganic salt concentration of the three media:
- Knop's Medium: Developed in 1865, this is a historical mineral nutrient solution with very simple, low-concentration mineral salts. It was originally used for basic plant physiology experiments and represents a Low salt strength medium.
- Gamborg's (B5) Medium: Developed in 1968, this medium has intermediate concentrations of inorganic salts, particularly lower levels of ammonium and nitrate compared to MS medium, making it a Medium salt strength formulation.
- Murashige and Skoog (MS) Medium: Formulated in 1962, MS medium features exceptionally high concentrations of macroelements, especially ammonium nitrate and potassium. It represents a High salt strength formulation designed for rapid cell division and regeneration.
Arranging these media in increasing order of salt strength:
\[ \text{Knop's Medium (Low)} < \text{Gamborg's Medium (Medium)} < \text{MS Medium (High)} \]
This matches Option (D).

Step 3: Final Answer:
The correct arrangement of basal media from low to high salt strength is Knop's Medium $<$ Gamborg's Medium $<$ MS Medium.