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The tree species Astronium graveolens (Anacardiaceae), Cedrela fissilis (Meliaceae), Gallesia integrifolia (Phytolaccaceae), Parapiptadenia rigida (Fabaceae) and Tabebuia avellanedae (Bignoniaceae) are found in remnants of tropical semideciduous forest in the North and Northwest of Paraná State and interior of the State of São Paulo. This study describes the morphological characteristics of seedlings in order to enable their identification in the field. Seedlings analyzed proved to be morphologically distinct from their cotyledons to eophylls and metaphylls and they may easily be distinguished in the plant community. All species showed leaves with petioles, and only C. fissilis and T. avellanedae presented eophylls. Cedrela fissilis has compounded eophyll, trifoliate, with integral edge, while in T. avellanedae it is simple, with serrated edge. Seedlings of G. integrifolia presented simple mesophyll, while the metaphyslls of C. fissilis, T. avellanedae and A. graveolens metaphylls are compounded; in P. rigida the metaphyll is bipinate. Since seedlings were visually distinct, the field's identification is possible.

The effects of Urucu crude oil on growth and biomass production of Echinochloa polystachya were studied experimentally. Young plants contaminated with 5 oil doses (0 to 2.64 l.m-2) were monitored at 1, 5, 10, 15 and 20 days after exposure. A significant reduction was observed in leaf humidity and the ratio of live aerial/ total biomass related to the increase in oil dosage. Increased exposition time caused a reduction in the number of leaves, aerial biomass, proportion of live aerial/total biomass, total biomass, and an increase of dead aerial biomass. However, root biomass and leaf length were not affected by exposure to oil. The low tolerance of E. polystachya to Urucu crude oil has lead to the mortality of 90% of the plant population in 20 days at the 2.64 l treatment. The death of young individuals of E. polystachya by relatively low dosages of Urucu oil indicates that, in the case of an oil spill in the Amazon varzea, this species would be severely affected, endangering, consequently, the entire environment. Resumo Os efeitos do petróleo cru de Urucu sobre o crescimento e a produção de biomassa da herbácea aquática amazônica Echinochloa polystachya foram estudados experimentalmente em casa de vegetação. Plantas jovens de E. polystachya foram contaminadas com 5 dosagens de petróleo (0 to 2,64 L.m-2) e avaliadas após 1, 5, 10, 15 e 20 dias da exposição. Ao término do experimento foi verificada uma significativa diminuição da proporção de biomassa aérea viva/total, da umidade das folhas e aumento do número de folhas com comprometimento fitossanitário, em resposta ao aumento da dosagem do petróleo. O aumento do tempo de exposição levou à diminuição do número de folhas, biomassa aérea, proporção de biomassa aérea viva/total, biomassa total e um aumento do número de folhas comprometidas e biomassa aérea morta. Contudo, a biomassa de raízes e o comprimento das folhas não foram afetados pela exposição ao petróleo. A baixa tolerância de E. polystachya ao petróleo de Urucu levou à mortalidade de 90% da população de mudas em 20 dias com o tratamento de 2,64 L.m-2. A perda de indivíduos jovens de E. polystachya em doses relativamente baixas do petróleo de Urucu indica que, no caso de um derramamento de óleo na várzea amazônica, esta espécie seria severamente afetada e, consequentemente, todo o ambiente.

Owing to their short life cycles aquatic macroinvertebrates may quickly respond to environmental modifications by changing the structure of their populations and communities. The aim of this study was to determine the relationship between the composition of aquatic macroinvertebrates associated with Eichhornia crassipes stands, the gradient of water conductivity and biomass of the roots of these stands. At the peak of the floods of 2005, 21 banks of floating aquatic macrophytes dominated by E. crassipes were sampled in the Solimões River (high conductivity > 50 μS cm -1), the confluence of these the rivers Solimões and Negro (medium conductivity > 30 μS cm -1 and ≤ 50 μS cm -1) and Negro River (low conductivity ≤ 30 μS cm -1). A total of 1707 aquatic macroinvertebrates were found, divided into 14 orders and 35 families. The abundance of aquatic invertebrates was higher in stands in the rivers confluence. The increased biomass of roots of E. crassipes led to an increase of abundance and richness of families of macroinvertebrates. The abundance of collector-gatherers, filter feeders and collector-scrapers varied with the type of water; only the abundance of collector-gatherers and collector-filter-varied with the root biomass. The abundance of collector-gatherers, filter feeders and collector-scrapers varied with the type of water, and only the richness of collectors and filter feeders varied with the root biomass. The family richness of collector-scrapers varied with the type of water. The organization of the community depends on the gradient of root biomass, showing that habitat structure is an important factor for the establishment of macroinvertebrates.

The Amazonian wetlands cover a vast area subject to a monomodal flood pulse with an annual amplitude averaging 10 m, which defines an aquatic phase and a terrestrial phase of great biological importance. According to the geological origin and the catchment areas, the physical and chemical properties of the wetland will vary, being defined two major groups, the várzeas and the igapós. Although aquatic herbaceous plants do occur in the two types, higher species richness and densities are typical of the várzeas where aquatic herbaceous species, particularly C4 plants may exhibit high biomass values and net primary production - NPP about three times these of the floodplain forest. The aquatic herbaceous plants are very important in the carbon and nutrient budgets of the várzea, since through their decomposition they promote the enrichment of the aquatic system and associated floodplains, both during the aquatic and terrestrial phases of the hydrologic cycle. The major threats to herbaceous aquatic plants are related to the modification and contamination of the habitats owing to their use in economic activities as cattle and buffalo ranching and agriculture. Degradation improves the susceptibility of these systems to fire especially during the terrestrial phase, resulting in economic losses and further degradation of floodplains. Recently oil spills linked to the petroliferous activities in the region are of major concern demanding further and urgent evaluation. As áreas alagáveis amazônicas cobrem uma vasta extensão de terrenos submetidos a um pulso de inundação monomodal de amplitude média anual de 10 m, definindo uma fase aquática e uma fase terrestre de grande importância biológica. Conforme a origem geológica e as áreas de captação, a físico-química das áreas alagáveis irá variar, sendo definidos dois grandes grupos, as várzeas e os igapós. Apesar das plantas herbáceas aquáticas ocorrerem nessas duas tipologias, a maior riqueza de espécies e densidades são típicas da várzea, onde espécies aquáticas herbáceas, especialmente de plantas C4 podem apresentar valores de biomassa e produção primária líquida - PPL cerca de três vezes os da floresta de várzea. As plantas herbáceas aquáticas são muito importantes no balanço de carbono e nutrientes da várzea, uma vez que através da sua decomposição elas promovem o enriquecimento do sistema aquático e das áreas alagáveis associadas, tanto durante a fase aquática quanto terrestre do ciclo hidrológico. As principais ameaças para plantas herbáceas aquáticas estão relacionadas com a alteração e contaminação do habitat, devido à sua utilização em atividades econômicas como a pecuária de gado e búfalo e agricultura. A degradação aumenta a suscetibilidade destes sistemas ao fogo, especialmente durante a fase terrestre, resultando em perdas econômicas e degradação adicional das áreas alagáveis. Recentemente derrames de óleo decorrentes das atividades petrolíferas na região são motivo de grande preocupação, exigindo urgentemente avaliação adicional.

Several factors may influence the impact of oil on the environment. However, although it is understood that the effect of pollutants may change throughout the year according to seasonal variations in environmental parameters, this effect is poorly studied in the tropical region. The effects of Urucu's crude oil on the vegetative propagation and growth of Echinochloa polystachya were evaluated in a 63 days period, in two experiments, "A" (July-September) and "B" (September-November) planting the species in a greenhouse. In both experiments parts of stems were placed in 2 L of várzea soil contaminated by 6 oil doses, ranging from 0 to 0.231 L oil m-2 soil. In response to dosage increase there was a decrease of total biomass, ratio of live /total biomass, the leaf length and number of leaves. The period of planting influenced the response of plants to the dosage applied due to climate change, with negative effects in the "B" period of higher temperatures. We concluded that the exposure period influence the vegetative propagation and growth of the seedlings, being a spill in the period of the higher temperatures more dangerous for this specie.

Para entender a ocorrência de P. glomerata na várzea amazônica, investigamos as respostas morfo-fisiológicas a longo período de inundação. Durante seis meses, plântulas de P. glomerata foram submetidas a dois tratamentos de inundação (parcial e total) para análise da assimilação fotossintética líquida (A), eficiência quântica do fotosistema II (referido como Fv/Fm), altura, número de folhas, diâmetro do colo do caule (DCC), área foliar e biomassa da planta. Encontramos um decréscimo da atividade de trocas gasosas, das taxas de crescimento e danos foliares com o aumento do nível de inundação. Após seis meses de experimento, a área foliar, a biomassa dos órgãos vegetativos (raiz, caule e folha) e a biomassa total das plântulas inundadas foram menores que das plântulas controle, plântulas não-inundadas. De acordo com o aumento do nível de inundação, a biomassa fotoassimilada foi alocada principalmente para o caule. Somente área foliar específica, razão raiz / parte aérea e massa seca de raiz não apresentaram diferenças entre os tratamentos. As plântulas totalmente inundadas foram fortemente comprometidas, demonstrando ser esta à condição mais crítica para a manutenção do metabolismo fisiológico. P. glomerata foi afetada pelo longo período de inundação, no entanto a espécie revela adaptações morfo-fisiologica que justifica a sua ocorrência em florestas de várzea. To understand the occurrence of P. glomerata in the Amazonian várzea we investigated the morpho-physiological responses to long-term flooding. Seedlings of P. glomerata were subjected to two flooding treatments (partial and total) for six months. Following flooding treatments, we examined light-saturated photosynthesis (A), the potential quantum yield of photosystem II (inferred as the Fv/Fm ratio), height, number of leaves (NF), stem diameter at the base of the plant (DCC), leaf area and plant biomass. We found a decrease in gas exchange parameters and growth rates, whereas leaf damage increased with flooding. After six months of flooding, leaf area, and the total plant biomass as well as the biomass of the vegetative organs (leaf, stem and root) were lower in flooded seedlings than in control, non-flooded plants. As flooding level increased assimilated carbon was mainly allocated to stems. However, flooding treatments had no significant effect on specific leaf area, the root/shoot ratio and dry mass of roots. Totally submerged roots of flooded seedlings were strongly affected, showing to be the most critical condition for maintenance of physiological metabolism. P. glomerata was affected by long-term flooding. Thus, P. glomerata exhibited adjusts morpho-fisiological which makes it possible for this species to occur in the Amazon floodplain forest.

A utilização de plantas para fitorremediação do solo requer que a concentração do poluente esteja dentro dos limites de tolerância da planta para que o tratamento seja eficaz. O rebrotamento e crescimento da herbácea aquática Echinochloa polystachya em solo de várzea contaminado por petróleo de Urucu foram estudados por meio do plantio de propágulos em frascos com 2 L de solo contaminado pela mistura de 7 dosagens de petróleo, distribuídas entre 0 e 0,46 L m-2. O experimento foi realizado em Casa de Vegetação e as plantas foram monitoradas durante 70 dias. Em resposta ao aumento da dosagem do petróleo, houve diminuição da biomassa aérea, da proporção de biomassa aérea viva/aérea total, do comprimento da folha e do número de folhas. A interação entre dosagem e tempo de exposição levou à diminuição do número de folhas, comprimento da folha, altura de inserção da primeira folha e aumento do número de folhas com comprometimento fitossanitário. A utilização de E. polystachya para fitorremediação pode estar limitada a solos com baixas dosagens de petróleo de Urucu. The use of plants for the phytoremediation of contaminated soils requires that the concentrations of the pollutant lay within the limits of tolerance of the plant in order to ensure the efficacy of the treatment. The vegetative propagation and growth of the aquatic herbaceous plant Echinochloa polystachya were studied by planting parts of stems in 2 L of várzea soils previously contaminated by crude oil from Urucu, in 7 different dosages of oil ranging from 0 to 0.46 L m-2. The experiment took place in a green house and the plants were monitored during a 70 days period. Increasing the oil concentration lead to the decrease of the above-ground biomass, the ratio alive aerial biomass/total aerial biomass, leaf length and number of leaves. The interaction between dosage and time of exposition contributed for a reduction in the number and length of leaves, height of insertion of the first leaf, and increase of the number of unhealthy leaves. The use of E. polystachya for phytoremediation may be limited to soils with lower concentrations of crude oil from Urucu.

The effect of root inundation on the leaf emissions of ethanol, acetaldehyde and acetic acid in relation to assimilation and transpiration was investigated with 2ĝ€"3 years old tree seedlings of four Amazonian floodplain species by applying dynamic cuvette systems under greenhouse conditions. Emissions were monitored over a period of several days of inundation using a combination of Proton Transfer Reaction Mass Spectrometry (PTR-MS) and conventional techniques (HPLC, ion chromatography). Under non-flooded conditions, none of the species exhibited measurable emissions of any of the compounds, but rather low deposition of acetaldehyde and acetic acid was observed instead. Tree species specific variations in deposition velocities were largely due to variations in stomatal conductance. Flooding of the roots resulted in leaf emissions of ethanol and acetaldehyde by all species, while emissions of acetic acid were only observed from the species exhibiting the highest ethanol and acetaldehyde emission rates. All three compounds showed a similar diurnal emission profile, each displaying an emission burst in the morning, followed by a decline in the evening. This concurrent behavior supports the conclusion, that all three compounds emitted by the leaves are derived from ethanol produced in the roots by alcoholic fermentation, transported to the leaves with the transpiration stream and finally partly converted to acetaldehyde and acetic acid by enzymatic processes. Co-emissions and peaking in the early morning suggest that root ethanol, after transportation with the transpiration stream to the leaves and enzymatic oxidation to acetaldehyde and acetate, is the metabolic precursor for all compounds emitted, though we can not totally exclude other production pathways. Emission rates substantially varied among tree species, with maxima differing by up to two orders of magnitude (25ĝ€"1700 nmol m−2 min −1 for ethanol and 5ĝ€"500 nmol m −2 min−1 for acetaldehyde). Acetic acid emissions reached 12 nmol m−2 min −1. The observed differences in emission rates between the tree species are discussed with respect to their root adaptive strategies to tolerate long term flooding, providing an indirect line of evidence that the root ethanol production is a major factor determining the foliar emissions. Species which develop morphological root structures allowing for enhanced root aeration produced less ethanol and showed much lower emissions compared to species which lack gas transporting systems, and respond to flooding with substantially enhanced fermentation rates and a non-trivial loss of carbon to the atmosphere. The pronounced differences in the relative emissions of ethanol to acetaldehyde and acetic acid between the tree species indicate that not only the ethanol production in the roots but also the metabolic conversion in the leaf is an important factor determining the release of these compounds to the atmosphere.

This research describes the influence of biotic and abiotic characteristics on fish fauna structure that inhabits the stands of aquatic macrophytes Eichhornia azurea and Eichhornia crassipes. 182 individuals were sampled belonging to 27 fish species in Camaleão lake, Central Amazonia. Values of dissolved oxygen and water temperature varied from 2.11 to 4.02mgL-1 and 29.17 to 30.93°C for the stands of E. crassipes, and from 1.29 to 2.59mgL-1 and 28.32 and 29.95°C for E. azurea. The highest number of fish species (24), individuals (134), biomass of roots (1572gm-2) belonged to E. azurea. Significantly differences among the stands were obtained to emerged portions (p