Salinity Induced Changes in the Leaf Anatomy of the Mangrove Avicennia Marina Along the Anthropogenically Stressed Tropical Creek

The mangrove Avicennia marina is a dominant mangrove along the anthropogenically stressed tropical Thane creek, west coast of India. Leaf anatomy of the mangrove along the Thane creek, was assessed in relation to stationwise and seasonwise variations in salinity. It was noticed that under the conditions of higher salinity, Avicennia marina showed increased thickness of hypodermal water storage tissue in the leaf (for conservation of water) and produced taller salt extruding glands at the lower epidermis to eliminate more salt; whereas, the thickness of the photosynthetic mesophyllic tissue significantly reduced. At lower salinity or with reduction in salinity in monsoon, contrary to above occurred. These changes probably explain the stunted growth of Avicennia marina in high salinity environment and its vigorous growth at lower salinity

An Approach to Evaluate Soils Influence on Floristic Composition of Natural Grasslands

This trial aims to evaluate floristic composition of most abundant species in three soil typical of Pampa biome on Brazil. The survey was held at Maronna Fundation located on southern Alegrete municipality, on Rio Grande do Sul, Brazil’s state. Regional climate belongs to Koeppen’s Cfa class. Soil types were shallow basalt (Psamments e Orthents), deep basalt (Vertisols) and sandy soil (Acrisols or Ultisols). Floristic composition were evaluated by visual ranking of aerial biomass of the major species (transformed to kg of dry matter per hectare), calibrated by cuts at ground level, according to field procedures of BOTANAL method. Grasses were clustered according to functional groups based on its leaf traits as proposed by Cruz et al. (2010). This approach proposed a ranking of grasses that ranges from its increasing leaf dry matter, and decreasing specific leaf area, from A to C groups. Total forage mass varied according to soil type. Contribution of A, B and C groups on total forage mass range from 40 to 60 %. Paspalum notatum, from B group, were found on the three soils, being more abundant on sandy and shallow basalt soils. Andropogon lateralis, from C group, was dominant on deep basalt soils, while Axonopus affinis, from A group, has higher biomass contribution on the same soil. We concluded that soil type affected floristic composition, even with this simplified diagnosis criteria

Armazenamento de sementes de taperebá em diferentes ambientes.

O taperebá (SpondiasmombinL.) é espécie frutífera originária da América tropical, comum na região Amazônica, onde ocorre no estado silvestre. Sementes de taperebá foram armazenadas durante 180 dias em temperaturas ambiente, de geladeira e freezer, e submetidas a avaliações periódicas para determinação do teor de água, da germinação e do vigor. O delineamento experimental adotado foi em esquema fatorial 3x4 (ambientes de armazenamento x tempo de armazenamento), com quatro repetições. As médias foram comparadas utilizando-se o teste de Tukey a 5%. Observou-se maior desempenho germinativo das sementes de S. mombin antes do armazenamento e nas sementes armazenadas em temperatura ambiente

Composição química do óleo essencial de 40 acessos de sacaca (Croton cajucara Benth) do banco de germoplasma da Embrapa Amazônia Ocidental.

A coleção de germoplasma de sacaca (Croton cajucara Benth.) da Embrapa Amazônia Ocidental teve início em 1997, com acessos coletados em 15 localidades da Região Norte, objetivando realizar o estudo de variabilidade entre elas, a conservação do germoplasma da espécie e selecionar genótipos superiores para a produção de biomassa (folhas) com maior potencial para a produção de óleo essencial rico em linalol. Dois morfotipos, definidos principalmente pela diferença na coloração das folhas, foram identificados na coleção e denominados sacaca branca e sacaca vermelha. Dentro das ações previstas nesta rede, está a avaliação da composição química dos óleos essenciais

Phase diagram of a random-anisotropy mixed-spin Ising model

We investigate the phase diagram of a mixed spin-1/2--spin-1 Ising system in the presence of quenched disordered anisotropy. We carry out a mean-field and a standard self-consistent Bethe--Peierls calculation. Depending on the amount of disorder, there appear novel transition lines and multicritical points. Also, we report some connections with a percolation problem and an exact result in one dimension.Comment: 8 pages, 4 figures, accepted for publication in Physical Review