INHIBITION OF NITRATE ASSIMILATION IN EXCISED WHEAT ROOTS BY VARIOUS RESPIRATORY POISONS

Abstract

The effects of certain respiratory poisons on the complete assimilation of nitrate and on the reduction of nitrate to nitrite by excised roots of wheat seedlings under anaerobic conditions were studied. Roots were allowed to accumulate nitrate from aerated KNO3 solns. and the effects of various treatments on the disappearance of the nitrate in the roots or on the appearance of nitrite were observed. CO had no inhibitory effect on assimilation of accumulated nitrate. Cyanide, azide, and iodoacetate inhibited nitrate assimilation. Formation of nitrite was inhibited by cyanide and iodoacetate. Since azide reacts rapidly with nitrite, the effects of that poison on nitrite formation could not be detd. unequivocally.