Miniaturised in vitro multiplication and/or regeneration of plant material under aseptic and controlled environmental conditions on specially prepared media that contain substances necessary for growth; used for three general types of tissue: excised embryos (= embryo culture); shoot-tips (= meristem culture or mericloning); and pieces of tissue that range from bits of stems to roots. Four stages of plant tissue culture have been defined by Murashige:

Stage I. Establishment of an aseptic culture.

Stage II. The multiplication of propagules.

Stage III. Preparation of propagules for successful transfer to soil (rooting and hardening).

Stage IV. Establishment in soil.