Photosynthetic strategies and Phosphorus use efficiency of Asteraceae species in campo rupestre

• Ano de defesa: 2022
• Autor(a) principal: Braga, Cecília Tavares Neves
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Universidade Federal de Viçosa; Manejo e Conservação de Ecossistemas Naturais e Agrários
• Palavras-chave em Português: Plantas - Fisiologia; Fotossintese; Fósforo; Campos Rupestres (Solo); Fisiologia Vegetal
• Link de acesso: https://locus.ufv.br//handle/123456789/30342; https://doi.org/10.47328/ufvcaf.2022.008

The threatened brazilian ferruginous campo rupestre, also known as canga is a fire prone and nutrient impoverished landscape, with high diversity of functional traits. The plant species found in this environment are generally characterized as of slow growth, higher leaf mass per area (LMA) and leaf dry mass content (LDMC), limited more by phosphorus (P) than nitrogen (N) when compared to other grasslands. In chapter one, a bibliographical review was conducted in order to establish the current state of P nutrition in those landscapes. In chapter two, the field work, conducted in the Serra da Calçada (MG, Brazil) during the rainy season of 2021 and 2022 was described. This work’s main goal was to understand the diversity of strategies to acquire and use P in Asteraceae species from ferruginous campo rupestre, regarding their functional traits and photosynthetic performance. To accomplish this, five Asteraceae species were selected: Dasyphyllum velutinum, Baccharis reticularia, Lychnophora pinaster, Trixis vauthieri and Hololepis pedunculata. A high diversity of functional traits, such as LMA, LDMC, foliar area and nutrient concentration was found. Some of which can be directly and indirectly related to the diversity of strategies to better absorb and use P. The species showed, in general, 70% mycorrhizal colonization and retranslocation rates of 77% and 65% for P and N, respectively. Even though these species have a diversity of functional traits, their photosynthetic P-use efficiency and P fractions (metabolic, nucleic acid, lipidic and residual) showed no significant difference. Finally, it was concluded that the diversity of functional traits found in Asteraceae species is most likely related by its phylogeny and the history of evolution of Asteraceae in the ferruginous campo rupestre. The ecological filters imposed by nutrient availability pressure during their evolutionary path have converged into a similar physiological performance. Keywords: P-fractions. Canga. Nutritional strategies. Photosynthetic P-use efficiency. Mycorrhiza. Convergence.