Reduction of Nitrate and Nitrite in Barley Leaves in Darkness
Reports are contradictory as to whether nitrate and nitrite are reduced in darkness in green leaves. Several workers report that nitrate is not assimilated in darkness in green leaves (Canvin and Atkins, 1974; Sawhney et al., 1978). Taken as evidence for a light requirement also for nitrite reduction is the coupling of nitrite reduction to photosynthetic electron flow at the level of ferredoxin (Miflin, 1974; Neyra and Hageman, 1974). Sadler and Scott (1974) observed that nitrite reduction is almost completely light-dependent and that the process does not require CO2 fixation in barley leaves. Sawhney et al. (1978) reported that nitrate reduction occurs only in light, so accumulation of toxic levels of nitrite in the dark is avoided. It has been proposed that nitrite is not found in darkness under aerobic conditions because O2 inhibits nitrate reduction (Sawhney et al., 1978; Atkins and Canvin, 1975).
KeywordsNitrate Reductase Green Leaf Nitrate Reduction Nitrate Reductase Activity Barley Leave
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- Sadler, R., and Scott, K. J., 1974, in: “Mechanisms of Regulation of Plant Growth,” R. L. Bieleski, A. R. Ferguson, M. M. Cresswell, eds., Bulletin 12, The Royal Society of New Zealand, Wellington.Google Scholar