Media - Plants in nature can synthesize their own food material. In contrast, plants growing in vitro are heterotrophic, Le., they cannot synthesize their own food material. Plant tissue culture media therefore require all essential minerals plus a carbohydrate source usually added in the form of sucrose and also other growth hormones (regulators and vitamins). Growth and morphogenesis of plant tissues in vitro are largely governed by the composition of the culture media. Although the basic requirements of cultured plant tissues are similar to those of whole plants, in practice nutritional components promoting optimal growth of a tissue under laboratory conditions may vary with respect to the particular species. Media compositions are thus formulated considering specific requirements of a particular culture system. 'For example, some tissues show better response on a solid medium while others prefer a liquid medium.