Cuticular wax composition contributes to different strategies of foliar water uptake in six plant species from foggy rupestrian grassland in tropical mountains.

The cuticle is the outermost region of the epidermal cell wall of plant aerial organs. The cuticle acts as a two-way lipid barrier for water diffusion; therefore, it plays a vital role in foliar water uptake (FWU). We hypothesised that the chemical composition of the cuticular waxes influences the FWU strategy that plants adopt in a foggy tropical ecosystem. We analysed the leaf cuticular waxes of six plant species known by their different FWU strategies, in both qualitative and quantitative approaches, to test this hypothesis. We also investigated the fine structure of the plant cuticle by scanning electron microscopy. Neither the total wax loads nor the amounts of single wax compound classes correlated to the FWU. In contrast, the qualitative chemical composition of the cuticular waxes was related to the water absorption speed but not to the maximum water absorbed. The presence of wax crystals might interfere with the FWU. Our findings suggest that a complex three-dimensional network of the cuticular compounds contributes to different strategies of FWU in six plant species from foggy tropical mountaintops.

In silico pharmacological prediction and cytotoxicity of flavonoids glycosides identified by UPLC-DAD-ESI-MS/MS in extracts of Humulus lupulus leaves cultivated in Brazil.

Ethanolic (EB) extract and hexanic (SH) and hydromethanolic (SEM) sub-extracts of Humulus lupulus leaves were submitted to cytotoxicity evaluation and to phytochemical methods. The effect of EB and SEM on cellular cycle was evaluated by propidium iodide method and the phases were quantified through flow cytometry. The cytotoxicity assessment was done using T24 and MRC5 cells, with EB and SEM (25-1200 µg/mL). By means of UPLC-DAD-MS/MS data were identified the flavonoids astragaline, nicotiflorin, kaempferol-7-O-rutinoside, robinin, hyperin, rutin, quercetin-7-O-rutinoside and manghaslin. EB (800 µg/mL) and SEM (1200 µg/mL) reduces the T24 cell viability. These extracts at 25 µg/mL stimulate the growth of MRC5 cells, evidencing a selective cytotoxicity. After 24 h of the treatment with extracts was not observed cycle arrest of T24 cells. The bioactivity prediction of the flavonoids was evaluated in silico through in house Active-IT software and PASSonline which indicated potential activity as antitumoral, cytotoxic, anti-inflammatory, antiparasitic, antimicrobial, antiviral and others.

Monitoring of forest components reveals that exotic tree species are not always invasive in areas under ecological restoration.

Exotic species are known to become invasive in several ecosystems, including areas undergoing restoration. But does that always happen? We monitored the tree layer, seed rain, and regenerating layer of 10-year and 20-year-old forests under restoration in southeast Brazil to verify if planted exotic trees were behaving as invasive; if they were influencing the species richness and abundance of regenerating native plants; and the probabilities of exotic trees perpetuating over time. Data from the three forest components (trees, seed rain, and regenerating) were collected in 12 permanent plots of 100 m2 each in each study area. Collected data were analyzed through generalized linear models (GLM) and Markov chains. We verified that exotic species were not behaving as invasive species. Of the five species planted, Acacia mangium, Syzygium cumini, and Psidium guajava were dispersing seeds but recruiting only six new individuals. In general, the species richness and abundance of exotic trees were not related to the richness and abundance of regenerating native plants. In addition, the chances of individuals' transition between forest components were in most cases nil, so that exotic species should continue not to spread in the 10- and 20-year-old forests. We assume that biotic resistance was occurring in the assembled communities and this prevented exotic trees from behaving as invaders. Monitoring of forest components helped to better understand the role of non-native species in the dynamics of these novel ecosystems. Monitoring also indicated that not all recovering forests need management actions against exotic trees after a decade or two of restoration.

Phanerogamic flora and vegetation of Itacolomi State Park, Minas Gerais, Brazil / Flora Fanerogâmica e Vegetação do Parque Estadual do Itacolomi, Minas Gerais, Brasil

Abstract Located in the municipalities of Ouro Preto and Mariana, in the Quadrilátero Ferrífero (QF) of Minas Gerais, the Itacolomi State Park (ISP) shelters more than 7,000 ha of remnants of Atlantic Forest and campos rupestres. The QF region has high biodiversity and is being highly impacted, mainly by mining activities. Aiming to organize the available floristic information and to support related research, this study presents the list of phanerogamic species of the ISP and the major vegetation types. This survey was carried out from October/1992 to July/2006, by monthly field trips. Besides authors´ personal collections, other records were assembled from herbarium databank. A total of 1623 taxons belonging to 122 families were listed. The families with higher species richness were Asteraceae, Fabaceae, Melastomataceae, Poaceae and Orchidaceae. The vegetation is represented by campos rupestres (51% of the total area), followed by montane forests (40%) and anthropogenic disturbed areas (9%). The greatest species richness occurs in campos rupestres. Several species are threatened and/or endemic. The knowledge of phanerogamic flora of ISP can help the Management Plan of this Unit of Conservation. It is also a contribution for future-related studies of the flora of ISP, Minas Gerais and Brazil.

Resumo O Parque Estadual do Itacolomi (PEIT) localiza-se nos municípios de Ouro Preto e Mariana, no Quadrilátero Ferrífero de Minas Gerais e abriga mais de 7.000 ha de remanescentes de mata atlântica e campos rupestres. A região do QF possui alta biodiversidade vegetal e está sobre alto impacto, principalmente pela mineração. O objetivo deste estudo foi apresentar a lista das espécies fanerogâmicas e os principais tipos vegetacionais desse Parque, no intuito de organizar a diversidade florística existente, além de servir como suporte para pesquisas correlatas subsequentes. O levantamento florístico foi realizado de outubro/1992 a julho/2006 por excursões mensais ao campo. Foram também incluídas na listagem registros ocorrentes em banco de dados de herbários. Foram identificados 1623 táxons, pertencentes à 122 famílias. As famílias mais representativas foram Asteraceae, Fabaceae, Melastomataceae, Poaceae e Orchidaceae. A vegetação do PEIT é constituída por campos rupestres (51% da área do parque), seguido pelas florestas montanas (40%) e por formações antrópicas (9%). A maior riqueza de espécies ocorre nos campos rupestres. Diversas espécies figuram em listas de espécies ameaçadas de extinção e outras são endêmicas. O conhecimento da flora fanerogâmica do Parque Estadual do Itacolomi pode subsidiar o Plano de Manejo dessa Unidade de Conservação e contribuir para futuros trabalhos correlatos nesta área, além de suprir conhecimentos para a flora de Minas Gerais e do Brasil.