Cell Wall Pigment Formation of in vitro Cultures of the Liverwort Ricciocarpos natans.

The liverwort Ricciocarpos natans has been cultivated on Gamborg B5 medium with different levels of ammonium, nitrate, phosphate and sucrose. The formation of the cell wall pigments riccionidin A and B was shown to be dependent on the level of these nutrients as well as on the intensity of light. A decrease in nitrogen supply (mainly nitrate) induced the formation of both wall pigments, whereas phosphate and high levels of sucrose inhibited the pigment synthesis. Decreasing the illumination rate led to lower anthocyanidin contents. Dedifferentiated cultures also produced wall pigments, but their amount was much lower compared to differentiated cultures.