Plant tissue culture is a collection of techniques used to grow plant cells, tissues, or organs in sterile conditions on a nutrient culture medium. It is fundamental to plant biotechnology, enabling micropropagation, genetic modification, germplasm conservation, and the production of secondary metabolites.

The theoretical basis of plant tissue culture is totipotency, the ability of any plant cell to regenerate a complete plant under appropriate conditions. This property is exploited in micropropagation, where explants are cultured to produce multiple cloned plantlets.

Culture media contain macro- and micronutrients, a carbon source (typically sucrose), vitamins, and plant growth regulators. Murashige and Skoog (MS) medium is the dominant formulation. Auxins such as indole-3-acetic acid (IAA) and naphthaleneacetic acid (NAA) promote root initiation, while cytokinins such as benzylaminopurine (BAP) and kinetin stimulate shoot formation. The ratio of auxin to cytokinin determines the developmental pathway.

Callus culture involves growing undifferentiated cell masses from explants on medium with balanced auxin and cytokinin levels. Callus can be used for secondary metabolite production or as starting material for cell suspension cultures. Somatic embryogenesis produces embryo-like structures from somatic cells, which can develop into complete plants. Anther and microspore culture produce haploid plants for breeding programs.

Micropropagation proceeds through explant establishment, shoot multiplication, rooting, and acclimatization. The multiplication stage uses cytokinin-rich medium to induce axillary shoot proliferation. Rooted plantlets are transferred to soil in a stepwise acclimatization process.

Applications include rapid propagation of elite cultivars, production of disease-free plants through meristem tip culture, conservation of endangered species, and large-scale production of secondary metabolites in bioreactors.