Plant tissue culture: Case study 3 - Tissue culture in teaching - Pictures of effects of tissue culture media on African violet

These pictures show the effects of changing the composition of a tissue culture medium that was designed originally for micropropagation of the common house plant, the African Violet.

The control medium contains: 4.71g. l^-1 Murashige and Skoog Inorganic salts medium, 0.5 mg.l^-1 naphthalene acetic acid (NAA, an auxin), 0.5 mg. l^-1 benzylamine purine (BAP, a cytokinin) and 3% sucrose, solidified by 1% agar. This Table summarises the composition of the medium.

Each picture shows the effect on the pattern of differentiation of increasing or decreasing one component of this medium. All are of approximately the same size of the original explant (1 cm square) The Figures are at a similar magnification.


Control Growth medium is optimised for regeneration of plantlets. The explant is completely covered with green shoots, and roots are developing on the lower surface (some visible at the sides).
No sucrose (0%) Very few shoots have developed on the explant. No roots and no callus.
Sucrose reduced to 1% Shoots developed on edges of upper surface, and some root development has occured.
Sucrose increased to 5% Shoots have developed over the surface of the explant, along with roots from the lower surface. The result is comparable with the control medium.
No BAP Profuse development of roots and a reduced number of shoots. Undifferentiated callus is developing at the edges of the explant.
BAP reduced to 0.1 mg. l^-1 More balanced development of roots and shoots. However, undifferentiated callus is developing at the edges of the explant.
BAP increased to 5.0 mg. l^-1 Reduced development of roots, shoots develop around edge of explant. Callus has initiated.
No NAA Poor shoot development and no roots.
NAA reduced to 0.1 mg. l^-1 Poor shoot development and no roots. Extensive callus generation.
NAA increased to 5.0 mg. l^-1 Profuse development of roots over the explant upper and lower surface, and few shoots. Some callus.
No MS salts No sign of regeneration from explant at all.
MS salts reduced to 0.47 g. l^-1 Some root growth but reduced development of shoots.
MS salts increased to 9.52 g. l^-1 Shoots developed on upper surface of explant. No roots or callus.