How do you induce callus formation in nutrient medium?

Explanation

In sterilized MS nutrient medium, the explant of size 1-2 cm sterile segment of leaf stemtuber or root is placed. The nutrient medium is supplemented with growth hormones like auxins. The explants in the medium is incubated at `25 pm 2^@C` in the culture chamber with alternate light and dark period of 12 hrs to induce cell division. The cells on the upper surface of the explant start dividing to form callus, which is a mass of unorganised cells or tissues grown invitro in culture medium.