RT info:eu-repo/semantics/article T1 Nitrogen form and concentration interact to affect the performance of two ecologically distinct Mediterranean forest trees A1 Uscola Fernández, María Mercedes A1 Oliet Palá, Juan Antonio A1 Villar Salvador, Pedro A1 Díaz-Pinés , Eugenio A1 Jacobs , Douglass F. K1 Ammonium K1 Ecophysiology K1 Growth K1 Nitrate K1 Pinus halepensis K1 Quercus ilex K1 Medio Ambiente K1 Environmental science AB Most studies examining inorganic N formeffects on growth and nutrition of forest trees have beenconducted on single species from boreal or temperateenvironments, while comparative studies with species fromother biomes are scarce. We evaluated the response of twoMediterranean trees of contrasting ecology, Quercus ilex L.and Pinus halepensis Mill., to cultivation with distinctinorganic N forms. Seedlings were fertilized with differentNH4?/NO3- proportion at either 1 or 10 mM N. In bothspecies, N forms had small effects at low N concentration,but at high N concentration they markedly affected theplant performance. A greater proportion of NH4? in thefertilizer at high N caused toxicity as it reduced growth andcaused seedling death, with the effect being greater in Q.ilex than in P. halepensis. An increase in the proportion ofNO3- at high N strongly enhanced growth relative to lowN plants in P. halepensis but had minor effects in Q. ilex.Relatively more NH4? in the fertilizer enhanced plant Pconcentration but reduced K concentration in both species,while the opposite effect occurred with NO3-, and these effects were enhanced under high N concentration. We conclude that species responses to inorganic N forms were related to their ecology. P. halepensis, a pioneer tree, had improved performance with NO3 - at high N concentration and showed strong plasticity to changes in N supply. Q. ilex, a late successional tree, had low responsiveness to N form or concentration. SN 1612-4669 YR 2014 FD 2014 LK http://hdl.handle.net/10017/37430 UL http://hdl.handle.net/10017/37430 LA eng NO Ministerio de Educación y Cultura DS MINDS@UW RD 30-nov-2023