
TY  - JOUR
A1  - Ledgard, SF 
A1  - Woo, KC 
A1  - Bergersen, FJ 
T1  - Isotopic Fractionation During Reduction of Nitrate and Nitrite by Extracts of Spinach Leaves
JF  - Functional Plant Biology
JO  - Functional Plant Biol.
Y1  - 1985
VL  - 12
IS  - 6
SP  - 631
EP  - 640
KW  - 
UR  - https://doi.org/10.1071/PP9850631 
N2  - The isotopic fractionations of nitrogen during the reduction of NO3- and NO2- in a cytosolic fraction and in a chloroplast preparation from spinach (Spinacia oleracea L.) leaves were determined. The reduction of NO3- to NH3 was studied using a reconstituted system containing cytosolic extract and intact chloroplasts, while a chloroplast system was used for NO2- reduction. In the reconstituted systems the ratio of nitrate reductase activity to nitrite reductase activity had a large effect on the relative amounts of NO2- and NH3 formed. Ammonia predominated when the nitrate reductase to nitrite reductase activity ratio was 1 : 5 and this ratio was used in the isotopic fractionation studies. Significant isotopic fractionation of N was observed in the reconstituted system but not in the chloroplast system. This indicates that the observed isotopic fractionation was associated with the reduction of NO3- to NO2- by nitrate reductase. The isotopic fractionation (i.e. &#948;15Nproduct - &#948;15Nsubstrate) for this reaction was - 15&#8240;. 
ER  -

