Published online by Cambridge University Press: 03 October 2008
Optimum conditions are described for the in vivo measurement of nitrate reductase activity in field-grown cotton leaves. The incubation period depended on light conditions prior to sampling. Addition of 1 mM glycolate had the effect of increasing apparent nitrate reductase activity on most days tested, and followed the general rhythmical pattern exhibited by the enzyme assayed without glycolate. While the in vivo assay appears to correlate well with soil nitrate levels, the choice of assay conditions does not appear to be absolutely critical.