Immunocytochemical evaluation of aquaporins and cell wall components and their influence on foliar water uptake in Andean Melastomataceae.

Andean ecosystems are characterized by high humidity, mainly from rain and fog events. Because of differences in altitude two Andean ecosystems - sub-Andean forest and Páramo -face different environmental pressures that affect leaf anatomy and cell wall composition and, consequently, species foliar water uptake (FWU) capacity. Here, FWU capacity of eight species in the Melastomataceae was evaluated and found to be related to proportions of cell wall components and aquaporins in the two ecosystems. Cellulose was labelled with Calcofluor white, and aquaporin and pectins were labelled with monoclonal antibodies. There were differences in plant FWU capacity in both ecosystems, with higher FWU capacity in sub-Andean forest species than in Páramo forest species. Cell wall components were positively related to FWU, with increased FWU related to pectin and aquaporin content of the plasma membrane. Differences in water availability in the two analysed environments led to differences in FWU capacity that are associated with leaf anatomical traits and cell wall composition. In these two environments, plants with similar traits are selected to respond to given environmental pressures. Traits that favour FWU in sub-Andean forest species may lead to further advances of these species in this environments.

An enhanced calibration of a recently released megatree for the analysis of phylogenetic diversity / Calibração aperfeiçoada de uma megatree lançada recentemente para a análise da diversidade filogenética

Abstract Dated or calibrated phylogenetic trees, in which branch lengths correspond to evolutionary divergence times between nodes, are important requirements for computing measures of phylogenetic diversity or phylogenetic community structure. The increasing knowledge about the diversification and evolutionary divergence times of vascular plants requires a revision of the age estimates used for the calibration of phylogenetic trees by the bladj algorithm of the Phylocom 4.2 package. Comparing the recently released megatree R20120829.new with two calibrated vascular plant phylogenies provided in the literature, we found 242 corresponding nodes. We modified the megatree (R20120829mod.new), inserting names for all corresponding nodes. Furthermore, we provide files containing age estimates from both sources for the updated calibration of R20120829mod.new. Applying these files consistently in analyses of phylogenetic community structure or diversity serves to avoid erroneous measures and ecological misinterpretation.

Resumo Árvores filogenéticas datadas, ou calibradas, em que os comprimentos dos ramos correspondem ao tempo evolutivo de divergência entre os nós, são importantes requisitos para calcular medidas de diversidade filogenética ou de estrutura filogenética de comunidades. O conhecimento crescente sobre a diversificação e sobre o tempo de divergência evolutiva das plantas vasculares fez necessária uma revisão das estimativas de idades dos nós que são utilizadas para a calibração de árvores filogenéticas por meio do algoritmo bladj do pacote Phylocom 4.2. Comparando a mega-árvore R20120829.new, recentemente publicada, e outras duas filogenias calibradas de plantas vasculares, encontramos 242 nós correspondentes. Modificamos esta mega-árvore (R20120829mod.new), inserindo todos os nomes dos nós correspondentes. Além disso, providenciamos dois arquivos com todas as estimativas das idades para uma calibração mais atualizada. Utilizando esses arquivos de maneira consistente nas análises de diversidade ou de estrutura filogenética de comunidades, evita-se incorreções nas datações e imprecisões na interpretação de informações ecológicas.

An enhanced calibration of a recently released megatree for the analysis of phylogenetic diversity.

Dated or calibrated phylogenetic trees, in which branch lengths correspond to evolutionary divergence times between nodes, are important requirements for computing measures of phylogenetic diversity or phylogenetic community structure. The increasing knowledge about the diversification and evolutionary divergence times of vascular plants requires a revision of the age estimates used for the calibration of phylogenetic trees by the bladj algorithm of the Phylocom 4.2 package. Comparing the recently released megatree R20120829.new with two calibrated vascular plant phylogenies provided in the literature, we found 242 corresponding nodes. We modified the megatree (R20120829mod.new), inserting names for all corresponding nodes. Furthermore, we provide files containing age estimates from both sources for the updated calibration of R20120829mod.new. Applying these files consistently in analyses of phylogenetic community structure or diversity serves to avoid erroneous measures and ecological misinterpretation.