Plant Cell Wall Research Related to Evolution and Chemical Defenses

The plant cell wall is composed mainly of polysaccharides some constituted of repeating units of a single sugar, as cellulose or by two or more sugars grouped in repeating oligosaccharide blocks as the galactomannans and xyloglucans. Variations in composition and fine structure of these cell wall polysaccharides have been used as taxonomic markers and in the comprehension of the evolutive process, particularly in the Leguminosae. Partial hydrolysis of these compounds give rise to oligomers, some of which are capable of eliciting the synthesis of defensive substances in plants named phytoalexins. Species which differ in respect to phytoalexin liberation also differ in cell wall composition, particularly in the pectic fraction of the wall. Pectinases (mainly endopolygalacturonases) present in fungi, have been shown to hydrolyze plant cell walls yielding phytoalexin-eliciting oligosaccharides which differ in composition and in eliciting capacity in different species. These differences can be associated with the capacity of a given species to produce phytoalexins. On the other hand, the phytoalexin induction in plants is being used as a method of producing novel bioactive secondary metabolites.

Changes in plant species composition and functional traits along the successional trajectory of a restored patch of Atlantic Forest

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Evolution of species diversity in the genus Chamaecostus (Costaceae): molecular phylogenetics and morphometric approaches

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Genetic and environmental heterogeneity of residual variance of weight traits in Nellore beef cattle

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The adaptive potential of a plant pathogenic fungus, Rhizoctonia solani AG-3, under heat and fungicide stress

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Relationship Among Phenolic Contents, Seed Predation, and Physical Seed Traits in Mimosa bimucronata Plants

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Floral anatomy of Bromeliaceae, with particular reference to the evolution of epigyny and septal nectaries in commelinid monocots

Floral anatomy is described in ten genera of Bromeliaceae, including three members of subfamily Bromelioideae, three Tillandsioideae, and four genera of the polyphyletic subfamily Pitcairnioideae (including Brocchinia, the putatively basal genus of Bromeliaceae). Bromeliaceae are probably unique in the order Poales in possessing septal nectaries and epigynous or semi-epigynous flowers. Evidence presented here from floral ontogeny, vasculature, and the relative positions of nectary and ovules indicates that there could have been one or more reversals to apparent hypogyny in Bromeliaceae, although this hypothesis requires a better-resolved phylogeny. Such evolutionary reversals probably evolved in response to specialist pollinators, and in conjunction with other aspects of floral morphology of Bromeliaceae, such as the petal appendages of some species. The ovary is initiated in an inferior position even in semi-epigynous or hypogynous species. The ovary of all so-called hypogynous Bromeliaceae is actually semi-inferior, because the septal nectary is infralocular; in these species the nectaries have a labyrinthine surface and many vascular bundles. Brocchinia differs from most other fully epigynous species in that each carpel is secretory at the apex and reproductive, rather than secretory, at the base.

The shared influence of phylogeny and ecology on the reproductive patterns of Myrteae (Myrtaceae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Root, shoot and leaf traits of the congeneric Styrax species may explain their distribution patterns in the cerrado sensu lato areas in Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Interspecific variation in the defensive responses of obligate plant-ants: experimental tests and consequences for herbivory

The aggressive behavior of ants that protect plants from herbivores in exchange for rewards such as shelter or food is thought to be an important form of biotic defense against herbivory, particularly in tropical systems. To date, however, no one has compared the defensive responses of different ant taxa associated with the same plant species, and attempted to relate these differences to longer-term efficacy of ant defense. We used experimental cues associated with herbivory-physical damage and extracts of chemical volatiles from leaf tissue-to compare the aggressive responses of two ant species obligately associated with the Amazonian myrmecophyte Tococa bullifera (Melastomataceae). We also conducted a colony removal experiment to quantify the level of resistance from herbivores provided to plants by each ant species. Our experiments demonstrate that some cues eliciting a strong response from one ant species elicited no response by the other. For cues that do elicit responses, the magnitude of these responses can vary interspecifically. These patterns were consistent with the level of resistance provided from herbivores to plants. The colony removal experiment showed that both ant species defend plants from herbivores: however, herbivory was higher on plants colonized by the less aggressive ant species. Our results add to the growing body of literature indicating defensive ant responses are stimulated by cues associated with herbivory. However, they also suggest the local and regional variation in the composition of potential partner taxa could influence the ecology and evolution of defensive mutualisms in ways that have previously remained unexplored.

Diversity of functional traits of fleshy fruits in a species-rich Atlantic rain forest

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Realized evolvability: quantifying phenotypic evolution in a Drosophila clade

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Using visual cues of microhabitat traits to find home: the case study of a bromeliad-living jumping spider (Salticidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Trait-mediated effects on flowers: Artificial spiders deceive pollinators and decrease plant fitness

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Fine-scale microhabitat selection in a bromeliad-dwelling jumping spider (Salticidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)