Age, pollen and spores of ODP Site 175-1082

The present-day condition of bipolar glaciation characterized by rapid and large climate fluctuations began at the end of the Pliocene with the intensification of the Northern Hemisphere continental glaciations. The global cooling steps of the late Pliocene have been documented in numerous studies of Ocean Drilling Program (ODP) sites from the Northern Hemisphere. However, the interactions between oceans and between land and ocean during these cooling steps are poorly known. In particular, data from the Southern Hemisphere are lacking. Therefore I investigated the pollen of ODP Site 1082 in the southeast Atlantic Ocean in order to obtain a high-resolution record of vegetation change in Namibia between 3.4 and 1.8 Ma. Four phases of vegetation development are inferred that are connected to global climate change. (1) Before 3 Ma, extensive, rather open grass-rich savannahs with mopane trees existed in Namibia, but the extension of desert and semidesert vegetation was still restricted. (2) Increase of winter rainfall dependent Renosterveld-like vegetation occurred between 3.1 and 2.2 Ma connected to strong advection of polar waters along the Namibian coast and a northward shift of the Polar Front Zone in the Southern Ocean. (3) Climatically induced fluctuations became stronger between 2.7 and 2.2 Ma and semiarid areas extended during glacial periods probably as the result of an increased pole-equator thermal gradient and consequently globally enhanced atmospheric circulation. (4) Aridification and climatic variability further increased after 2.2 Ma, when the Polar Front Zone migrated southward and the influence of Atlantic moisture brought by the westerlies to southern Africa declined. It is concluded that the positions of the frontal systems in the Southern Ocean which determine the locations of the high-pressure cells over the South Atlantic and the southern Indian Ocean have a strong influence on the climate of southern Africa in contrast to the climate of northwest and central Africa, which is dominated by the Saharan low-pressure cell.

Pollen analysis of surface sediments from the Gulf of Guinea and offshore NW-Africa

The areas of marine pollen deposition are related to the pollen source areas by aeolian and fluvial transport regimes, whereas wind transport is much more important than river transport. Pollen distribution patterns of Pinus, Artemisia, Chenopodiaceae-Amaranthaceae, and Asteraceae Tubuliflorae trace atmospheric transport by the northeast trades. Pollen transport by the African Easterly Jet is reflected in the pollen distribution patterns of Chenopodiaceae-Amaranthaceae, Asteraceae Tubuliflorae, and Mitracarpus. Grass pollen distribution registers the latitudinal extension of Sahel, savannas and dry open forests. Marine pollen distribution patterns of Combretaceae-Melastomataceae, Alchornea, and Elaeis reflect the extension of wooded grasslands and transitional forests. Pollen from the Guinean-Congolian/Zambezian forest and from the Sudanian/Guinean vegetation zones mark the northernmost extension of the tropical rain forest. Rhizophora pollen in marine sediments traces the distribution of mangrove swamps. Only near the continent, pollen of Rhizophora, Mitracarpus, Chenopodiaceae-Amaranthaceae, and pollen from the Sudanian and Guinean vegetation zones are transported by the Upwelling Under Current and the Equatorial Under Current, where those currents act as bottom currents. The distribution of pollen in marine sediments, reflecting the position of major climatic zones (desert, dry tropics, humid tropics), can be used in tracing climatic changes in the past.

“Opciones alimenticias para mitigar problemas de inseguridad alimentaria y nutricional en familias pobres de comunidades rurales del municipio de Tisma, Masaya Nicaragua en el año 2014”

El estudio valor a el estado nutricional de las familias en las siguientes comunidades: Santa Cruz, Tisma Grande y la Montañita N o 2, pertenecientes al municipio de Masaya. Se inició con el análisis de sus patro nes de consumo, dando valor al aporte nut ricional de las plantas locales . En esta investigación cualit ativa se aplicaron los siguientes instrumentos : Entrevistas y recorr idos de fincas . De estos se derivan dos estudios de casos. El primero reflejó que los 9 patr ones de consumo poseen suficiencia en cuanto al acceso a alimentos nutritivos superando el 110%. El índice de di versidad de la dieta ( suficiencia ) en la semana, alcanza un rango de 0.89 en Tisma Grande, con valoración deficiente, en Santa Cruz de 0.92 con valoración aceptable y l a Montañita N o 2 de 1.08, con valoración adecuad a . En el aspecto de la diversidad de l a dieta en la semana , los resultados fuer on rangos promedios entre 9.3 y 9.7 significando la existencia de una diver sidad de dieta aceptable. El segundo estudio de caso refleja info rmac ión sobre los tipos de plantas locales con valor nutritivo y las formas de consumo diario determina n do así las siguientes plantas: Espinaca ( Spinacia oleracea ), Quelite ( Amaranthus hybridus ), Espadillo ( Yucca elephantipes ), Verdolaga ( Portulaca olerac ea ), Mora ( Morus nigra), Cojombro (Sicana odorífera), Batata (Ipomoea batatas), Piñuela (Bromelia baratas), Panamá (Sterculia apetala, Tempisque (Sideroxylon capiri), Caimito (Chrysophyllum cainito) entre otras . Definitivamente , podemos detallar que las f amilias consumen alimentos con mayo r aporte calórico que proteínico, ya que consumen alimentos derivados de los lácteos, car nes y dulces. Sin embargo, es importante mencion ar que esto no indica que exista una mala calidad nu tricional en las familias, puest o que el consumo de proteínas no es tan defi ci ente, por eso hace necesario incluir a limentos que permitan compleme ntar el consumo de proteínas al organismo de las familias, logrando así un a dieta balanceada que les permita a las familias mejorar sus condic iones de salud y de vida satisfaciendo así sus necesidades nutricionales diarias en relación al tr ab ajo que realizan día a día en sus pequeñas parcelas productivas.

Effects of nitrogen level on purslane antioxidant activity.

The high antioxidant activity of purslane, Portulaca oleracea L., gives it a high nutritional and functional value. The commercial production of purslane has increased in Portugal, making it necessary to know the effects of inputs, mainly nitrogen, on the antioxidant activity. The main goal of this study was to evaluate the influence of nitrogen application on purslane antioxidant activity. The experiment was carried out with for treatments: 30, 60 and 90 kg/ha of nitrogen. Plants of golden-leaf purslane were grown in Styrofoam-boxes filled with substrate and fertigated two times per week, over four weeks with ammonium nitrate solution (16.9% NO3-N and 16.7 NH4+-N). The increase in the nitrogen level decreased the water-soluble proteins content. However the ascorbate, phenols content as well as antioxidant activity measured by FRAP method was not affected by nitrogen level. Plants shoot antioxidant activity, measured by DPPH method decreased significantly in the treatment with 90 kg N/ha (26.20 g/g gallic acid). On the other hand, plant shoot antioxidant activity mediated by peroxidases was higher in treatment 30 kg N/ha (0.459 µmol min-1/mg prot.). Application of 60 kg N/ha allowed a vigorous plant growth without disturb its antioxidants and conservation properties.

Hospedabilidade de plantas daninhas a Meloidogyne enterolobii.

O objetivo deste trabalho foi avaliar a hospedabilidade de dezesseis espécies de plantas daninhas, Acanthospermum australe, Ageratum conyzoides, Alternanthera tenella, Amaranthus hybridus, A. viridis, Bidens pilosa, Digitaria horizontalis, Eleusine indica, Euphorbia heerophylla, Hyptis sauaveolens, Ipomoea grandifolia, I. nil, Portulaca oleracea, Solanum americanum, Sida cordifolia e tagetes sp. ao nematoide-das-galhas, Meloidogyne enterolobil.

Potencial de uso da erva medicinal Cybopogon citratus no controle de fitopatógenos do feijoeiro e plantas daninhas em áreas irrigadas.

Para avaliar a erva medicinal Cymbopogon citratus (capim-limao) no controle de fitopatogenos e de plantas daninhas em feijoeiro, foram instalados experimentos utilizando diferentes subprodutos da planta. O oleo essencial de C. citratus a 10% obtido de folhas inibiu totalmente o crescimento micelial de Fusarium solani f. sp phaseoli, Sclerotinia sclerotiorum e Rhizoctonia solani, ao passo que Sclerotium rolfsii apresentou-se menos sensivel, apesar da substancia reduzir significativamente o diametro medio das colonias do fungo. Tambem o oleo de C. citratus a 10% promoveu inibicao total da germinacao de sementes de Digitaria horizontalis (capim-colchao), Sorghum halepense (capim-massambara), Bidens pilosa (picao-preto), Euphorbia heterophylla (amendoim-bravo, leiteiro) e Raphanus raphanistrum (nabica). O oleo inibiu parcialmente a germinacao de Echinochloa crusgalli (capim-arroz) e nao afetou a germinacao de Portulaca oleracea (beldroega). Em casa de vegetacao, o oleo de folhas a 10% afetou a emergencia do feijoeiro, enquanto o po (folha seca moida) incrementou a emergencia para 97% contra 75% e 88% em solos infestados com R. solani e F. solani, respectivamente. Em condicoes de campo, observou-se reducao da incidencia de F. solani e R. solani nas parcelas tratadas com suspensao aquosa de oleo de C. citratus a 1% e 5% no sulco de plantio e em tratamento de sementes a 0,5%. A analise da producao nao evidenciou diferencas significativas entre os tratamentos. Para verificar o efeito da combinacao do uso de C. citratus e da reducao de doses dos herbicidas, foram ultilizados os herbicidas pos-emergentes fomesafen e fenoxaprop-etil nas doses usadas pelo produtor (0,619 l ia/ha de cada produto) e a 80% destas doses. As especies de plantas daninhas predominantes foram: P. oleracea, Eleusine indica (capim-pe-de-galinha) e Amaranthus deflexus (caruru).