NUTRIENT REQUIREMENT FOR OPTIMAL-GROWTH OF SUGARCANE SUSPENSION CELLS - NICOTINIC-ACID IS AN ESSENTIAL GROWTH-FACTOR

The usually used complex growth medium containing yeast extract was substituted to achieve optimal growth of sugarcane suspension cells in a chemically defined medium. The intention was to reveal special growth factors which are needed for sugarcane cells in culture, to learn about nutrient requirement of sugarcane parenchyma and to lay a basis for continuous culture of sugarcane cells with defined nutrients in limitation. It was found that yeast extract has to be substituted by a) an amino acid mixture, which corresponds to the total nitrogen content of yeast extract including the peptides, b) some elevation of phosphate and c) especially essential, an additional provision of nicotinic acid above the level which is already present in the usual vitamin mixtures. Extra supply of other nutrient elements had no growth-promoting effect. The amino acids could be replaced by ammonium salts provided that the resulting acidification of the medium was kept low, either by buffers or by continuous medium replacement. The newly formed chemically defined medium may be applicable for the cultivation of all those plant cells which, because of lack of nitrate uptake or nitrate reduction, are unable to grow on Murashige-Skoog medium or other media, which rely on nitrogen nutrition by nitrate.