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Accueil du site → Doctorat → Espagne → 2001 → Els fenols, entre el carboni i el nitrogen. Resposta als increments de CO2 atmosfèric i interacció amb el cicle del nitrogen

Universitat Autònoma de Barcelona (2001)

Els fenols, entre el carboni i el nitrogen. Resposta als increments de CO2 atmosfèric i interacció amb el cicle del nitrogen

Castells Caballé, Eva

Titre : Els fenols, entre el carboni i el nitrogen. Resposta als increments de CO2 atmosfèric i interacció amb el cicle del nitrogen

Auteur : Castells Caballé, Eva

Université de soutenance : Universitat Autònoma de Barcelona.

Grade : Doctoral Tesis 2001

Résumé
Phenolic compounds are plant carbon-based secondary metabolites of high interest in ecological studies because they can regulate the strength of some biotic interactions. At specific level, phenolic compound concentrations are determined by abiotic factors such as plant C and N availability. An increasing atmospheric CO2 could influence the synthesis of phenolics and these changes could have further consequences in ecological processes highly related to secondary metabolism. We first studied changes in phenolic concentrations in Mediterranean species growing at elevated CO2. It is generally accepted that increased carbon source for plants results in an increase of carbon-based secondary compounds when growth is limited by other resources. However, the validity of this response is mainly unknown in plants growing in natural conditions. We wanted to know : i) whether there was a genetic variability in the response of phenolic compounds at elevated CO2, ii) the effects of plant diversity in the response of phenolics at elevated CO2, and iii) the long term response of phenolic compounds in plants submitted to elevated CO2. Our results show that, at short term, phenolic concentrations increased under elevated CO2 in plants growing close to natural conditions, and this response was related to the studied species but not to the genotypes, functional groups or plant diversity. At long term, phenolic concentrations had no significant increase in plants growing in naturals conditions. We second studied the role of phenolic compounds in controlling N cycling in Boreal and Mediterranean ecosystems, where soil is N limited. Thus, we analyzed the effects of plant presence from two phenolic compound-bearing species (Ledum palustre and Cistus albidus) on N cycling, as well as the effects of leaf leachates containing high phenolic compound concentrations. Our results shown that leachates can change soil N cycling under both plant species, but these effects are not due to phenolic compounds. We conclude that phenolic compounds are not the main drivers controlling soil N availability in natural conditions

Mots Clés : Cicle del nitrogen — Elevat CO2 — Fenols

Présentation et version intégrale (TDX)

Page publiée le 14 octobre 2015, mise à jour le 31 janvier 2019