In the preparation of culture media, different stock solutions (ATOG) are made. Generally stock solutions of major elements are prepared by 10X final concentration whereas minor elements and vitamins are prepared by 1000X final concentration and stored in the freezer.

Stock solutions:

A – NH4NO3

B – KNO3

C – CaCl2.2H2O

D – KH2PO4

E — Molybdenum

CaCl2

KI

F — MnSO4

MgSO4

CuSO4

ZnSO4

G — Na2EDTA

FeSO4.7H2O

1. Dispense 1000 mL of double distilled H2O into the flask. Mark the level and remove 300 mL of H2O.

2. Keep water for boiling.

3. Dissolve appropriate concentration of sucrose when water becomes warm.

4. Pipette out different concentrations of stock solutions into a separate container.

5. Mix all stock solutions thoroughly.

6. Adjust pH of the medium by 0.1N HCl and NaOH.

7. Dissolve agar in boiling water.

8. Dispense culture media into tubes or flask and close with plugs. Autoclave for sterili­zation.