Present and Past Research

Underground leaves of Philcoxia trap and digest nematodes
The recently described genus Philcoxia comprises three species restricted to well lit and nutrient-poor soils in the Brazilian Cerrado. The morphological and habitat similarities of Philcoxia to those of known carnivorous plants, along with observations of nematodes over its subterranean leaves, prompted the suggestion that the genus is carnivorous. In this study we reported compelling evidence of carnivory in Philcoxia of the Plantaginaceae, a family in which no carnivorous members are otherwise known. We also documented both a unique capturing strategy for carnivorous plants and a case of a species that traps and digests nematodes with underground adhesive leaves. Our findings illustrate how much can still be discovered regarding the origin, distribution, and frequency of the carnivorous syndrome in angiosperms and, more generally, about the diversity of nutrient-acquisition mechanisms that have evolved in plants growing in severely nutrient-impoverished environments such as the Brazilian Cerrado, one of the world's 34 biodiversity hotspots (Myers et al., 2000).



Philcoxia minensis and the worldwide leaf economics spectrum
Research on carnivorous plants began more than a century ago, yet it is still unclear what are the mechanisms that determine the evolution and/or distribution of these singularities. The cost-benefit models have been, in this context, acting as guidelines to several surveys in recent decades and they appear to be able to elucidate many obscure points regarding the ecology of these species. The genus Philcoxia, endemic to the campos rupestres - fire prone and nutrient poor areas associated with white-sand formations and rocky outcrops - display some characteristics that led to inquiries about its physiology and evolution. Our research group has shown that the species of this genus are carnivorous, but we do not yet know the role that this syndrome plays in the energetic balance of these species. This study aimed to analyse the costs and the benefits of the carnivorous syndrome in Philcoxia minensis in the theoretical context suggested by Thomas J. Givnish (1984).



Physiological and molecular aspects of phosphorus efficiency in Proteaceae and beyond
In my PhD thesis, I analysed several aspects of highly-efficient use of phosphorus (P) in Proteaceae and beyond, with a special focus on the implications of P-efficiency mechanisms on species distribution. In the first chapters, my goal was to analyse the extremely high P-use efficiency of Proteaceae from severely P-impoverished habitats across the Jurien Bay dune chronosequence in south-western Australia and its link with P toxicity. In summary, I found that high sensitivity to calcium (Ca)-enhanced P toxicity is one of the leading factors explaining the distribution of calcifuge Proteaceae, and that this is due to the cell-specific interactions of P and Ca and their effects on the zinc (Zn) metabolism. In the last chapter, I explored the P-allocation pattern of Proteaceae, a trait that partially explains these species’ exceptionally high PPUE and a defining factor explaining the phenomenon of Ca-enhanced P toxicity. I performed the first survey to determine whether the allocation of P to the mesophyll has evolved exclusively in Proteaceae or, alternatively, if it evolved multiple times in other species that naturally occur in P-impoverished environments. In summary, my thesis provides insight into strategies allowing efficient use of P in Proteaceae and beyond, particularly those associated with nutrient allocation patterns at the leaf-tissue level. This is the first time patterns of P allocation are considered in terms of P use efficiency in plants, and the results suggest that these are relevant traits in explaining the functioning of species and their natural distribution. My research also highlights the impact of nutrient-allocation patterns on the phenomenon of P toxicity, which will be useful for the improvement of management practices involving P-sensitive plants.