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Zn-biofortification enhanced nitrogen metabolism and photorespiration process in green leafy vegetable Lactuca sativa L.

BACKGROUND
Excessive rates of nitrogen (N) fertilizers may result in elevated concentrations of nitrate (NO3- ) in plants. Considering that many programs of biofortification with trace elements are being performed, it has become important to study how the application of these elements affects plant physiology and, particularly, N utilization in leaf crops. The main objective of the present study was to determine whether the NO3- accumulation and the nitrogen use efficiency was affected by the application of different doses of Zn in Lactuca sativa plants.


RESULTS
Zn doses in the range 80-100 µmol L-1 produced an increase in Zn concentration provoking a decrease of NO3- concentration and increase of the nitrate reductase, glutamine synthetase and aspartate aminotransferase activities, as well as the photorespiration processes. As result, we observed an increase in reduced N, total N concentration and N utilization efficiency. Consequently, at a dose of 80 µmol L-1 of Zn, the amino acid concentration increased significantly.


CONCLUSION
Adequate Zn fertilization is an important critical player in lettuce, especially at a dose of 80 µmol L-1 of Zn, because it could result in an increase in the Zn concentration, a reduction of NO3- levels and an increase the concentration of essential amino acids, with all of them having beneficial properties for the human diet. © 2016 Society of Chemical Industry.