The medium used for propagation of an explant in vitro is called nutrient medium or culture medium. This medium must provide a carbon source such as sucrose and also inorganic salts, vitamins, amino acids and growth regulators like auxins, cytokinins with or without the use of yeast extract or coconut milk or banana pulp. The culture medium can be kept liquid, made semisolid with gelatin or solidified with agar.