Role of light in the regulation of the nitrate reductase level in wheat (Triticum aestivum)

The relationship between light and NR synthesis was studiedin excised wheat leaves. In light, there was a 14 fold increasein the NR level as compared to the dark controls. Sucrose didnot have any effect on NR synthesis. In the dark, a significantamount of intracellular nitrate was detected, but there wasvery little NR activity. Measurement of the decay rates of NRin the dark and light showed that NR activity disappeared fasterin light than in the dark. Exposure to short durations of blue,red and white light caused an increase in the NR synthesis.Further, this response was found to be phytochrome controlled.We propose that the process of nitrate reduction influencesNR synthesis. (Received January 11, 1979; )