Potencial de alguns defensivos agrícolas naturais para o controle de doenças de mamão papaya na pós-colheita.

As principais doenças que afetam o mamão papaya na pós-colheita são a antracnose (Colletotrichum gloeosporioides) e a podridão causada por Stemphylim lycopersici. Neste trabalho, avaliaram-se os efeitos de extratos de frutos (ES) maduros de sucupira-branca (Pterodons pubescens Benth), leite natural tipo C (LN), leite fermentado por 12 horas a 23°C (LF), leite UHT (LE), leite em pó (LP), pó de diatomito (Protego) a 1,5% e benomil a 0,1%, como fungicida-padrão.Título em inglês: Potential of some natural pesticides to control of post-harvest diseases on papaya

Efeito de defensivos agrícolas naturais no controle de doenças de maracujá-doce e de goiaba na pós-colheita.

As principais doenças que afetam o maracujá-doce na pós-colheita são a antracnose, podridão de Botryodiplodia e a mancha de Alternaria. Para a goiaba, as mais expressivas são a antracnose, podridão de Dothiorella Dominicana e a mancha-preta (Guignardia psidii). Neste trabalho, avaliaram-se os efeitos de extrato de frutos(ES) maduros de sucupira-branca (Pterodons pubescens benth),leite natural tipo C (LN), leite fermentado por 12 horas a 23°C (LF), leite fermentado por 24 horas a 23°C (LFc), leite UHT (LE), leite em pó (LP), pó de diatomito (Protego) a 1,5 %, e benomil a 0,1% como fungicida-padrão. No preparo do ES, 1 kg de frutos maduros foi macerado e colocado em 2,5 litros de etanol, onde permaneceu por 5 dias na ausência de luz. Deste extrato, retiraram-se 600 ml e acrescentaram-se, a este volume, mais 150 ml de água destilada. Com o auxilio de um ventilador, o volume inicial de 750 ml foi concentrado até 150 ml. Destes, retirou-se uma alíquota de 50 ml que foi misturada em um litro de água, compondo o tratamento ES. Os frutos, colhidos de vez, foram imersos nessas caldas por um minuto, colocados em caixas de papelão-padrão e mantidos a 23°C e UR de 65%. O del. exp. Foi inteiramente casualizado com 15 repetições de um fruto. As avaliações foram efetuadas aos 12 dias após os tratamentos, determinando-se a severidade (% da casca do fruto ocupada com lesões) das doenças. Para o maracujá-doce, os melhores resultados foram obtidos com o ES, seguido pelo LN, LE, benomil a 0,1% e diatomito a 1,5%. O LP, LF e LFc foram estatisticamente semelhantes à testemunha. Para a goiaba, o melhor tratamento foi o ES, seguido por benomil a 0,1%, LF, diatomito e LN que foram estatisticamente semelhantes. LFc e LE também apresentaram algum efeito em comparação com a testemunha. LP não foi efetivo.Título em inglês: Effect of natural pesticides to control of post-harvest diseases on sweet passion fruit and guava

Persistent effects of pre-Columbian plant domestication on Amazonian forest composition

The extent to which pre-Columbian societies altered Amazonian landscapes is hotly debated. We performed a basin-wide analysis of pre-Columbian impacts on Amazonian forests by overlaying known archaeological sites in Amazonia with the distributions and abundances of 85 woody species domesticated by pre-Columbian peoples. Domesticated species are five times more likely to be hyperdominant than non-domesticated species. Across the basin the relative abundance and richness of domesticated species increases in forests on and around archaeological sites. In southwestern and eastern Amazonia distance to archaeological sites strongly influences the relative abundance and richness of domesticated species. Our analyses indicate that modern tree communities in Amazonia are structured to an important extent by a long history of plant domestication by Amazonian peoples

Geography and ecology shape the phylogenetic composition of Amazonian tree communities.

Aim Amazonia hosts more tree species from numerous evolutionary lineages, both young and ancient, than any other biogeographic region. Previous studies have shown that tree lineages colonized multiple edaphic environments and dispersed widely across Amazonia, leading to a hypothesis, which we test, that lineages should not be strongly associated with either geographic regions or edaphic forest types. Location Amazonia. Taxon Angiosperms (Magnoliids; Monocots; Eudicots). Methods Data for the abundance of 5082 tree species in 1989 plots were combined with a mega-phylogeny. We applied evolutionary ordination to assess how phylogenetic composition varies across Amazonia. We used variation partitioning and Moran's eigenvector maps (MEM) to test and quantify the separate and joint contributions of spatial and environmental variables to explain the phylogenetic composition of plots. We tested the indicator value of lineages for geographic regions and edaphic forest types and mapped associations onto the phylogeny. Results In the terra firme and várzea forest types, the phylogenetic composition varies by geographic region, but the igapó and white-sand forest types retain a unique evolutionary signature regardless of region. Overall, we find that soil chemistry, climate and topography explain 24% of the variation in phylogenetic composition, with 79% of that variation being spatially structured (R2 = 19% overall for combined spatial/environmental effects). The phylogenetic composition also shows substantial spatial patterns not related to the environmental variables we quantified (R2 = 28%). A greater number of lineages were significant indicators of geographic regions than forest types. Main Conclusion Numerous tree lineages, including some ancient ones (>66 Ma), show strong associations with geographic regions and edaphic forest types of Amazonia. This shows that specialization in specific edaphic environments has played a long-standing role in the evolutionary assembly of Amazonian forests. Furthermore, many lineages, even those that have dispersed across Amazonia, dominate within a specific region, likely because of phylogenetically conserved niches for environmental conditions that are prevalent within regions.Na publicação: Joice Ferreira

Biased-corrected richness estimates for the Amazonian tree flora

Amazonian forests are extraordinarily diverse, but the estimated species richness is very much debated. Here, we apply an ensemble of parametric estimators and a novel technique that includes conspecific spatial aggregation to an extended database of forest plots with up-to-date taxonomy. We show that the species abundance distribution of Amazonia is best approximated by a logseries with aggregated individuals, where aggregation increases with rarity. By averaging several methods to estimate total richness, we confirm that over 15,000 tree species are expected to occur in Amazonia. We also show that using ten times the number of plots would result in an increase to just ~50% of those 15,000 estimated species. To get a more complete sample of all tree species, rigorous field campaigns may be needed but the number of trees in Amazonia will remain an estimate for years to come

One sixth of Amazonian tree diversity is dependent on river floodplains.

Amazonia’s floodplain system is the largest and most biodiverse on Earth. Although forests are crucial to the ecological integrity of floodplains, our understanding of their species composition and how this may differ from surrounding forest types is still far too limited, particularly as changing inundation regimes begin to reshape floodplain tree communities and the critical ecosystem functions they underpin. Here we address this gap by taking a spatially explicit look at Amazonia-wide patterns of tree-species turnover and ecological specialization of the region’s floodplain forests. We show that the majority of Amazonian tree species can inhabit floodplains, and about a sixth of Amazonian tree diversity is ecologically specialized on floodplains. The degree of specialization in floodplain communities is driven by regional flood patterns, with the most compositionally differentiated floodplain forests located centrally within the fluvial network and contingent on the most extraordinary flood magnitudes regionally. Our results provide a spatially explicit view of ecological specialization of floodplain forest communities and expose the need for whole-basin hydrological integrity to protect the Amazon’s tree diversity and its function

Unraveling Amazon tree community assembly using Maximum Information Entropy: a quantitative analysis of tropical forest ecology.

In a time of rapid global change, the question of what determines patterns in species abundance distribution remains a priority for understanding the complex dynamics of ecosystems. The constrained maximization of information entropy provides a framework for the understanding of such complex systems dynamics by a quantitative analysis of important constraints via predictions using least biased probability distributions. We apply it to over two thousand hectares of Amazonian tree inventories across seven forest types and thirteen functional traits, representing major global axes of plant strategies. Results show that constraints formed by regional relative abundances of genera explain eight times more of local relative abundances than constraints based on directional selection for specific functional traits, although the latter does show clear signals of environmental dependency. These results provide a quantitative insight by inference from large-scale data using cross-disciplinary methods, furthering our understanding of ecological dynamics