DELAYED NH3 AND N2O UPTAKE BY MAIZE LEAVES

N-15 was used to give evidence of NH3 and N2O absorption by maize leav es. A short-term labelling method (90 min) was chosen with high NH3 co ncentration (40 mul l-1) to assess uptake mechanisms. Two initial entr y pathways were suggested for NH3: fast uptake with immediate metaboli sm and fast storage with progressive metabolism. A storage compartment delayed NH3 absorption after exposure. Similar mechanisms might be in volved in N2O uptake.