Introduction to Media Preparation

In plant tissue culture (PTC), the media preparation is the major event.  The growth regulators and the nutrient medium must be formulated correctly to support plant tissue development. This guide walks you through the calculation of stock solutions for plant growth regulators such as IAA and Kinetin, alongside the preparation of MS media.

Stock Solution Calculations

To prepare a stock solution of Indole-3-acetic acid (IAA), determine the desired concentration, typically 1 mM, 10 mM, or 100 mM. Using the formula Mass (g) = Molarity (M) × Volume (L) × Molecular Weight (g/mol), calculate the required amount of IAA, where the molecular weight of IAA is 175.18 g/mol. For example, to prepare 100 mL of a 10 mM stock solution, dissolve 175.18 mg of IAA in a small volume of ethanol (70–100%) or a few drops of 1N NaOH, as IAA is poorly soluble in water. Once fully dissolved, adjust the volume to 100 mL using distilled water or a suitable buffer, such as phosphate buffer. Since IAA is light-sensitive and degrades over time, store the solution in an amber bottle or wrap it in aluminum foil. For long-term storage, keep it at -20°C, while aqueous solutions should be stored at 4°C and used within a few weeks. If preparing higher concentrations, such as 100 mM, using 100% ethanol or DMSO is recommended for better solubility. Additionally, filter-sterilization (0.22 µm filter) is necessary for applications in plant tissue culture.

MS Media Preparation Example

The Murashige and Skoog (MS) medium consists of macro and micronutrients, vitamins, and agar. The concentration of these components can vary based on the specific requirements of the plant being cultured. Below is an example table showcasing typical concentrations:

Overall, precise calculations are fundamental to effective plant tissue culture media preparation. Following this structured approach allows for optimized growth conditions tailored to the requirements of specific plants.