NITROGEN-SOURCE AND THE EFFECT OF GROWTH-REGULATORS ON AMMONIUM ASSIMILATION ENZYMES IN TISSUE-CULTURE OF CANAVALIA-ENSIFORMIS (L) DC

Ammonium assimilation enzymes in Canavalia ensiformis (L.) DC. calli r espond differentially to the N source in the culture medium when subcu ltured under different hormonal regimes. With 1 mM NH4+ the aminative and deaminative activities of GDH were not affected by the auxin, so t he observed changes were due to the different nitrate concentrations i n the medium. When NH4+ was increased to 5 mM, there was a marked incr ease with NAA and a NO3- dose effect was noticed. GS activity was not affected by the ammonium concentration but it was affected by both nit rate and the auxin type, with NAA promoting higher activities.