title: High nitrate supply reduces growth in maize, from cell to whole plant.
abstract: Nitrogen (N) is an essential macronutrient that limits agricultural productivity, and both low and high N supply have been suggested to alter plant growth. The overall aim of this work is to study the impact of nitrate (NO3(-)) in maize yield and the possible causes that induce this alteration. High NO3(-) doses did not increase the yield of maize grown neither in the field nor under controlled conditions. In fact, plants grown under controlled conditions for 45 days with NO3(-) concentrations over 5mM showed a decrease in biomass production. This reduction was perceptible in shoots prior to roots, where phytomer expansion was reduced. Cell size and number were also reduced in the leaves of plants with high NO3(-). This alteration was correlated with the increase of 1-aminocyclopropane-1-carboxylic acid in leaves, which was probably translocated from the roots in order to synthesize ethylene. Cytokinins (CKs) also showed a relevant role in this inhibitory effect, increasing in high NO3(-) plants with a reduction in root and shoot growth, inhibition of apical dominance and a strong decrease of leaf expansion, symptoms described previously as "CK syndrome". We propose that high NO3(-) inhibits maize growth by causing hormonal alterations that modify plant growth from cell to whole plant.
authors.affiliation: Department of Plant Biology and Ecology, Faculty of Pharmacy, University of Basque Country UPV/EHU, P° de la Universidad 7, Vitoria-Gasteiz E-01006, Spain. Electronic address: inigo.saiz@ehu.es.
authors.forename: Iñigo
authors.initials: I
authors.lastname: Saiz-Fernández
authors.affiliation: Department of Plant Biology and Ecology, Faculty of Pharmacy, University of Basque Country UPV/EHU, P° de la Universidad 7, Vitoria-Gasteiz E-01006, Spain; Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 11, 783 71 Olomouc, Czech Republic. Electronic address: nuria.de@upol.cz.
authors.forename: Nuria
authors.initials: N
authors.lastname: De Diego
authors.affiliation: Department of Analytical Chemistry, Faculty of Pharmacy, University of Basque Country UPV/EHU, Vitoria-Gasteiz E-01006, Spain. Electronic address: mariacarmen.sampedro@ehu.es.
authors.forename: Maria Carmen
authors.initials: MC
authors.lastname: Sampedro
authors.affiliation: Department of Plant Biology and Ecology, Faculty of Science and Technology, University of Basque Country UPV/EHU, E-48080 Leioa, Spain. Electronic address: amaia.mena@ehu.es.
authors.forename: Amaia
authors.initials: A
authors.lastname: Mena-Petite
authors.affiliation: Department of Plant Production and Protection, Research Institute for Agricultural Development, Basque Country, NEIKER-Tecnalia, Ap. 46, E-01080 Vitoria-Gasteiz, Álava, Basque Country, Spain. Electronic address: aortizb@neiker.net.
authors.forename: Amaia
authors.initials: A
authors.lastname: Ortiz-Barredo
authors.affiliation: Department of Plant Biology and Ecology, Faculty of Pharmacy, University of Basque Country UPV/EHU, P° de la Universidad 7, Vitoria-Gasteiz E-01006, Spain. Electronic address: maite.lacuesta@ehu.es.
authors.forename: Maite
authors.initials: M
authors.lastname: Lacuesta
mesh_terms: D000598:Amino Acids, Cyclic / Q000378:metabolism*; D018533:Biomass; D003583:Cytokinins / Q000378:metabolism; D009566:Nitrates / Q000494:pharmacology*; D009584:Nitrogen / Q000378:metabolism; D019441:Plant Epidermis / Q000166:cytology / Q000187:drug effects / Q000254:growth & development; D018515:Plant Leaves / Q000166:cytology / Q000187:drug effects / Q000254:growth & development; D018517:Plant Roots / Q000166:cytology / Q000187:drug effects / Q000254:growth & development; D018520:Plant Shoots / Q000166:cytology / Q000187:drug effects / Q000254:growth & development; D003313:Zea mays / Q000166:cytology / Q000187:drug effects* / Q000254:growth & development
chemical_list: D000598:Amino Acids, Cyclic; D003583:Cytokinins; D009566:Nitrates; C023863:1-aminocyclopropane-1-carboxylic acid; D009584:Nitrogen
keywords: 1-Aminocyclopropane-1-carboxylic acid; Cytokinins; Nitrate; Ontogeny; Phytomer