Evidence for a complex control system for nitrate reductase in wheat leaves

The influence of light on the activity of nitrate reductase in synchronous cultures of Chlorella pyrenoidosa

“…A similar light-dependence of nitrate reductase has been found in several higher plants [4][5][6][7]9, 1 I], pro ducing daily fluctuations of the enzyme activity [8].…”

Diurnal Fluctuations in the Activity of the Enzyme Nitrate Reductase in Lemna paucicostata

“…Diurnal fluctuations in the activity of nitrate reductase were observed for the first time in corn (Hageman et al 1961). Similar fluctuations were later shown in Lolium (Bowerman and Goodman 1971), wheat (Upcroft and Done 1972), soybean (Harper and Hageman 1972) and rice seedlings (Shibata et al 1969). Cohen and Cumming (1974) found an endogenous rhythm in the activity of nitrate reductase in Chenopodium rubrum with peaks at 15, 30 and 45 h. Such rhythmicity has also been observed recently by Steer (1974) and Pearson and Steer (1977) in Capsicum anmium.…”

IMMUNOLOCALIZATION OF NITRATE REDUCTASE IN THE MARINE DINOFLAGELLATE GONYAULAX POLYEDRA (PYRROPHYTA)1

“…In our ongoing studies on diurnal and circadian rhythms in the unicellular dinoflagellate alga, Conyzulnx p o l y d r a , we examined cells from both day and night phases for their ability to bind a NR antibody produced from G o u~n u l a s cells. An earlier study on this enzyme in G o u~a u l a s (Ramalho et al 1995) concluded that NR is synthesized and degraded in a daily rhythm controlled by the cell's biological clock, similar to that for NR regulation in wheat (Upcroft and Done 1972) and tobacco (Deng et al 1990). We, therefore, surmised that the location of NR in day-phase cells, when the enzyme is more abundant and active, should represent the site where this enzyme is active, tvhereas labeling patterns in night-phase cells should show less antibody binding due to the enzyme's nighttime degradation.…”