Nitrate assimulation in shoot-forming tobacco callus cultures

Summary The contents of nitrogen-containing compounds and the activities of nitrate assimilating enzymes were determined in tobacco callus cultured under shoot-forming and non-shoot-forming conditions. Whole tissue and tissues cut into top and bottom portions were examined. Highes levels of total-N, protein-N, nitrate and ammonium-N, as well as higher activities of nitrate and nitrite reductases were found in shoot-forming whole tissue and in the shoot-forming bottom portion of tobacco callus in comparison to the non-shoot-forming proliferating tissues throughout the culture period. These findings indicate that enhanced nitrogen assimilation occurs during de, de novo shoot organogenesis. This work was supported by NSERC of Canada Grant No. A-6467 to T.A.T.