Question

Which of the following will be present in the highest amount in the plant tissue culture media

• A. $\text{H}_3\text{BO}_4$
• B. $\text{NH}_4\text{NO}_3$
• C. NAA
• D. Glycine

Hint:

Macronutrients (such as $\text{NH}_4\text{NO}_3$, $\text{KNO}_3$, and $\text{CaCl}_2 \cdot 2\text{H}_2\text{O}$) are added in gram or high-milligram quantities per liter, whereas micronutrients and vitamins are added in microgram or low-milligram quantities.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Plant tissue culture formulations (such as Murashige and Skoog, or MS medium) consist of macronutrients, micronutrients, vitamins, amino acids, carbon sources, and plant growth regulators. These components are added in vastly different quantitative ranges.

Step 2: Detailed Explanation:
Let us compare the typical concentrations of these components in standard MS medium:
- Ammonium nitrate ($\text{NH}_4\text{NO}_3$): A major macronutrient that serves as a primary source of nitrogen. It is added in macronutrient quantities, typically around $1650 \text{ mg/L$} ($20.6 \text{ mM}$).
- Boric acid ($\text{H}_3\text{BO}_4$): A micronutrient needed in small quantities, typically around $6.2 \text{ mg/L$}.
- Glycine: An organic amino acid supplement added in trace amounts, typically around $2.0 \text{ mg/L$}.
- Naphthaleneacetic acid (NAA): A synthetic auxin plant growth regulator used in hormone amounts, typically ranging from $0.1\text{ to 2.0 \text{ mg/L}$}.
Therefore, the macronutrient $\text{NH}_4\text{NO}_3$ is present in the highest concentration by weight.

Step 3: Final Answer:
The compound present in the highest concentration is $\text{NH}_4\text{NO}_3$.