Light-sucrose interaction stimulates nitrate uptake by wheat roots

To improve nitrate uptake efficiency and minimize fertilizer waster, nitrate uptake control was investigated. In the previous work, we found that illuminating shoots can stimulate nitrate uptake by wheat (Triticum aestivum cv. "EM18") roots, which is thought to be via a signal carried through phloem, maybe a sugar. We also found that sucrose could show features of a specific signal of nitrate uptake. A noninvasive technique method with a high-time resolution (minutes) has enabled us to make the comparison between illumination and sucrose supply. Interestingly, the results showed when plants were in the light, the stimulation by external sucrose was less than that in the dark, indicating light affected nitrate uptake co-operatively with externally supplied sucrose. The interaction between light and externally supplied sucrose showed that the mechanism of light effect on nitrate uptake involved sucrose. This work was useful for further investigating its molecular mechanism and ultimately improving nitrogen use efficiency.