The Regulation of Genuine Light Effect and Diurnal Rhythms on Nitrate Uptake by Plant Roots

Nitrate uptake can be affected by light. However, the genuine effect of light and darkness (e.g. changing the intensity of light received by the above-ground part of plants) is different from the internal diurnal variation (biological clock), which also has a certain effect on N uptake and could be affected by light. In order to better understand their difference, the research situation of nitrate uptake affected by light effects and diurnal regulation has been systematically summarized here. Among the reported researches, studies on Holcus lanatus, Populus tremula, Ricinus communis, etc. clearly showed that it was the diurnal variation. Reported studies on Hordeum vulgare, Lactuca ativa and Triticum aestivum mainly showed light/dark effects. Some reported studies reflected that nitrate uptake was affected by both, indicating that plants were not only affected by diurnal variation, but also regulated by light. To better investigate the influence of light on nitrate uptake, it is necessary to compare the differences between diurnal variation and light effect.