**5. Summary**

The suitable sterilisation method for stevia seeds is method D, which gave 14.29% per cent contamination, while that of Chicory was method C, which gave 30% per cent contamination. However, for Bee balm and *Rhodiola krylovii,* the four methods used for sterilisation and cultivation yielded very high percentage contamination of 100%, which signifies that Bee balm and *Rhodiola krylovii* need a different method of sterilisation, and this can be concluded that each plant cell requires a specific sterilisation method for increasing yield and lowering microbial contamination. The use of growth regulators for callus formation and shoot regeneration should be used when obtaining the callus of medicinal plants. Hence, this can be seen in the cultivation process of callus of Chicory, Bee balm, and *Rhodiola krylovii,* which showed an increased growth rate and percentage contamination of 62.5% for both chicory and Bee balm and 75% while the callus of the same plants grown in media without Kinetin showed no growth. They had a very high percentage contamination of 100% for the same plant species (see **Figure 25**).

**Figure 25.** *Obtaining cell cultures of medicinal plants.*
