title: Zn-biofortification enhanced nitrogen metabolism and photorespiration process in green leafy vegetable Lactuca sativa L.
abstract: 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-1produced 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-1of Zn, the amino acid concentration increased significantly.
  
  
  CONCLUSIONS
  Adequate Zn fertilization is an important critical player in lettuce, especially at a dose of 80 µmol L-1of 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.
authors.affiliation: Department of Plant Physiology, Faculty of Sciences, University of Granada, 18071, Granada, Spain.
authors.forename: Yurena
authors.initials: Y
authors.lastname: Barrameda-Medina
authors.affiliation: Dipartimento di Biologia, Università di Napoli 'Federico II', Complesso Universitario di Monte Sant'Angelo, Via Cinthia, 80126, Napoli, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Lentini
authors.affiliation: Dipartimento di Biologia, Università di Napoli 'Federico II', Complesso Universitario di Monte Sant'Angelo, Via Cinthia, 80126, Napoli, Italy.
authors.forename: Sergio
authors.initials: S
authors.lastname: Esposito
authors.affiliation: Department of Plant Physiology, Faculty of Sciences, University of Granada, 18071, Granada, Spain.
authors.forename: Juan M
authors.initials: JM
authors.lastname: Ruiz
authors.affiliation: Department of Plant Physiology, Faculty of Sciences, University of Granada, 18071, Granada, Spain.
authors.forename: Begoña
authors.initials: B
authors.lastname: Blasco
mesh_terms: D000072759:Biofortification; D005308:Fertilizers / Q000032:analysis; D005527:Food, Fortified / Q000032:analysis*; D005974:Glutamate-Ammonia Ligase / Q000378:metabolism; D018545:Lactuca / Q000737:chemistry / Q000201:enzymology / Q000378:metabolism*; D050901:Nitrate Reductase / Q000378:metabolism; D009566:Nitrates / Q000032:analysis / Q000378:metabolism; D009584:Nitrogen / Q000032:analysis / Q000378:metabolism*; D018515:Plant Leaves / Q000737:chemistry / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism; D014675:Vegetables / Q000378:metabolism*; D015032:Zinc / Q000032:analysis / Q000378:metabolism*
chemical_list: D005308:Fertilizers; D009566:Nitrates; D010940:Plant Proteins; D050901:Nitrate Reductase; D005974:Glutamate-Ammonia Ligase; D015032:Zinc; D009584:Nitrogen
keywords: Lactuca sativa; Zn biofortification; nitrate accumulation; nitrogen use efficiency