Efeito da temperatura e a participação do fitocromo no controle da germinação de sementes de embaúba

A embaúba é considerada uma espécie pioneira que ocorre na mata Atlântica, principalmente em borda da mata ou em matas secundárias. O presente trabalho teve como objetivo a análise da influência da temperatura e do modo de ação da luz através de curva de fluência resposta, para a melhor compreensão do comportamento das sementes desta espécie. Através de incubações isotérmicas foi determinada que a temperatura ótima de germinação de sementes de Cecropia glaziovi, situa-se entre 25 e 30ºC e a saturação da indução da germinação com luz branca mediada pelo fitocromo ocorreu com 1W.m-2. Embora as sementes de embaúba necessitem de luz de alta razão de V:VE para a indução do processo, a germinação ocorreu em fluência baixa de luz branca, indicando alta sensibilidade dessas sementes ao ambiente aberto, como borda de matas e pequenas clareiras. Estas características indicam a participação do fitocromo B no controle da germinação de sementes nesta espécie.

Brazilian savanna forest : conservation, medicinal reservoir and bioprospecting

This study aimed to analyse the Brazilian savanna forest from a Legal Reserve (LR) area from a perspective of conservation, reservoir of organic carbon and medicinal biomass for a prospective use of native medicinal plants. An ethnobotanical and ethnopharmacological survey was carried out close to a community settled in the rural area in the south of Tocantins, being selected 9 of the most cited species (cajuí- Anacardium othonianum; inharé-Brosimum gaudichaudii; jatobá-Hymenaeae courbaril; jenipapo-Genipa americana, aroeira-Myracrodruon urundeuva; negramina-Siparuna guianensis; barbatimão- Stryphnodendron obovatum; assa peixe-Vernonia brasiliana, embaúba-Cecropia pachystachya). Crude foliar extracts were subjected to a preliminary phytochemical prospection and triage of secondary metabolites with antimicrobial activity of potential interest in health and familiar agriculture. Phenolic compounds, terpenes and flavonoids were detected in the extracts of most species, which suggests the presence of antimicrobial, antioxidant and anti-insect activities. It was evident the need to better know the LR as a reservoir of medicinal biomass in an area under ecological tension where 35% (610ha) of the property is LR and should be protected by law. Therefore, a forest inventory of live woody species was performed using the allometric or indirect method. This identified a rare remnant of Semidecidual Seasonal Forest amidst the largest world savannah, the Cerrado biome. An analysis of the forest average productivity per basal area (m².ha), aerial live biomass (ton.ha-1) and carbon stock was carried out. The forest fragment was considered relatively rich in species and diversity, although showing signs of disturbance and dominance by a few species. Its horizontal structure suggests biotic regeneration conditions. It is an important reservoir of medicinal plants. Of the families (57.5%) presenting medicinal species, 19 from a total of 33 are represented in the area and contain 44% (27) of the total species (61) and 63% (432) of the total individuals catalogued. Medicinal species have ecological importance for the equilibrium of the local flora and represent 80% of the 10 species with higher Importance Value Index (IVI): Tetragastris altissima, Chrysophyllum marginatum, Oenocarpus distichus, Sclerolobium paniculatum, Simarouba versicolor, Alibertia macrophylla, Siparuna guianensis, Maprounea guianensis, Licania parvifolia e Physocalymma scaberrimum. Medicinal productivity was high for this type of phytophysionomy: 183,2 ton. ha-1 of biomass and 91,51 ton. ha-1 of carbon representing 66% of the total biomass and carbon of this Cerrado forest. From this stage S. guianensis (Siparunaceae) was selected for performing bioassays in order to verify its biological activity against microorganisms of health and agricultural relevance. This is a native aromatic medicinal plant recommended as priority for conservation, with local popular medicinal validation and availability of medicinal feedstock (3300 Kg.ha-1), with the foliar fraction giving 38Kg/ha of crude extract and 5L/ha of essential oil. Foliar crude extracts and essential oil were obtained and tested in vitro using a disk diffusion bioassay. Different concentrations of these natural products were tested against gram-positive bacteria (Staphylococcus aureus ATCC 29213), gram-negative bacteria (Escherichia coli ATCC 25922 and ATCC 35218; Pseudomonas aeruginosa ATCC 10145) and fungi (Candida albicans ATCC 6258 e Fusarium oxysporum). The essential oil inhibited the growth of S. aureus in its crude concentration (380μg.mL-1), as well as diluted to half (190μg.mL-1) and a quarter strength (95μg.mL-1). It’s likely that such action is due to sesquiterpenes major components, such as bisabolol and bisabolene (10.35%), measured by gas chromatography (GC-MS, GC-FID). Extracts did not exhibit any antimicrobial activity against the microorganisms tested. The native medicinal plants prospective market is an alternative that favours the conservation of biodiversity while generating benefits for the development of sustainable family productive activities within local ecosystems instead of the current inappropriate uses. This strengthens conservation policies of Legal Reserve in rural settlements and is in agreement with public policy on global warming and climate changes.

Sorption and desorption of phosphate on biochar and biochar-soil mixtures

The term biochar refers to materials with diverse chemical, physical and physicochemical characteristics that have potential as a soil amendment. The purpose of this study was to investigate the P sorption/desorption properties of various slow biochars and one fast pyrolysis biochar and to determine how a fast pyrolysis biochar influences these properties in a degraded tropical soil. The fast pyrolysis biochar was a mixture of three separate biochars: sawdust, elephant grass and sugar cane leaves. Three other biochars were made by slow pyrolysis from three Amazonian tree species (Lacre, Ingá and Embaúba) at three temperatures of formation (400 °C, 500 °C, 600 °C). Inorganic P was added to develop sorption curves and then desorbed to develop desorption curves for all biochar situations. For the slow pyrolysis, the 600 oC biochar had a reduced capacity to sorb P (4-10 times less) relative to those biochars formed at 400 °C and 500 °C. Conversely, biochar from Ingá desorbed the most P. The fast pyrolysis biochar, when mixed with degraded tropical mineral soil, decreased the soil's P sorption capacity by 55% presumably because of the high soluble, inorganic P prevalent in this biochar (909 mg P/kg of biochar). Phosphorus desorption from the fast pyrolysis biochar/soil mixture not only exhibited a common desorption curve but also buffered the soil solution at a value of ca. 0.2 mg/L. This study shows the diversity in P chemistry that can be expected when biochar is a soil amendment and suggests the potential to develop biochars with properties to meet specific objectives. © 2013 British Society of Soil Science.

Influência de Cecropia pachystachya na incidência de ácaros (Arachnida, Acari) e de Leptopharsa heveae (Insecta, Hemiptera) em cultivo de seringueira

Cecropia pachystachya is a plant native to the states of Mato Grosso and São Paulo, usually found in rubber tree plantations. The goals of this study were to verify: a) whether the presence of C. pachystachya in rubber tree plantations influences the occurrence of mites in rubber trees; b) whether it can be used as a reservoir of predaceous mites; c) whether it serves as an alternative host for Leptopharsa heveae during the natural senescence of rubber trees. This study was conducted in two rubber tree plantations in São José do Rio Preto, in the state of São Paulo, Brazil. One of them had numerous naturally growing individuals of C. pachystachya, while the other was free of spontaneous plants. We registered high richness of predaceous mites on C. pachystachya, but only 37.5% of them were found on rubber trees, which reveals low displacement rate of mites between the plants. Among the species that were common to both plants, only the predaceous Zetzellia agistzellia and the phytophagous mites Allonychus brasiliensis and Eutetranychus banksi were influenced by the presence of C. pachystachya. The incidence of L. heveae did not differ between the plantations under study and, moreover, C. pachystachya was not used as an alternative host by this insect, since no individuals were registered on its leaves during the natural senescence of rubber trees.

Índice de importância de diferentes espécies de plantas na atração de aves para uma área reflorestada em Piracicaba

A restauração de áreas degradadas pode beneficiar espécies típicas do ambiente original, com a expansão e criação de habitats, tornando-se uma ferramenta de extrema importância para a conservação. Frugívoros atraídos por plantas zoocóricas utilizadas em plantios não apenas podem dispersar sementes dessas plantas como também trazer sementes alóctones, promovendo a diversidade genética local. Assim, é fundamental entender as condições em que o processo de dispersão de sementes opera, a fim de subsidiar programas de recuperação ambiental. Este trabalho avaliou a importância das espécies: embaúba (Cecropia pachystachya), pitanga (Eugenia uniflora), figueira-do-brejo (Ficus insipida), aroeira-pimenteira (Schinus terebinthifolius), pau-pólvora (Trema micranta), fumo-bravo (Solanum mauritianum) na atração de aves frugívoras em uma Área de Preservação Permanente de 6,2 ha replantada em 2006 no município de Piracicaba, São Paulo. Apenas C. pachystachya, E. uniflora e F. insipida foram utilizadas no plantio, o que indica que as outras espécies foram introduzidas pela fauna. Observações focais foram realizadas em pelo menos dois indivíduos de cada espécie, totalizando dez horas de observação por espécie. Foram registradas 29 espécies de aves alimentandose dos frutos. Utilizando-se de uma adaptação da fórmula de Murray (2000) para o índice de importância na atração da avifauna, foram encontrados os valores de 0,086 para C. pachystachya, 0,031 para E. uniflora, 0,020 para F. insipida, 0,123 para S. terebinthifolius, 0,083 para S. mauritianum e 0,623 para T. micrantha. O grande valor observado para essa última em relação às outras pode ser justificado pelo grande número de espécies visitantes e de relações exclusivas, especialmente com aves que são predominantemente insetívoras ou granívoras. A importância de T. micrantha provavelmente se deve à alta concentração de lipídios em seu fruto. Os...