DIURNAL FLUCTUATIONS IN NITRATE UPTAKE AND NITRATE ACCUMULATION IN LETTUCE (LACTUCA SATIVA L.).

Experiments were carried out to study the diurnal fluctuation of nitrate accumulation of outer leaves and nitrate uptake of roots in Lactuca sativa (lettuce) plants cv LM 6211. The plants were cultivated in a Nutrient Film Technique system with 10 mmol NO₃ 1^-1 in the nutrient solution.
It was found that the nitrate uptake in plants grown under a normal dark/light regime had two peaks, one during the early part of the night, and the second at about midday.

Nitrate accumulation within the leaf tissue showed a single peak during the night period.
Plants given a low light period which was during the night were found to have only one nitrate uptake peak during the daytime.

Workshop on Ecological Aspects of Vegetable Fertilization in Integrated Crop Production in the Field

Gilda A. Carrasco, S. W. Burrage

https://doi.org/10.17660/ActaHortic.1993.339.12