Wetland plants are being used successfully for the phytoremediation of trace elements in natural and constructed wetlands. This study demonstrates the potential of water hyacinth (Eichhornia crassipes), an aquatic floating plant, for the phytoremediation of six trace elements. The ability of water hyacinth to take up and translocate six trace elements—As(V), Cd(II), Cr(VI), Cu(II), Ni(II), and Se(VI)—was studied under controlled conditions. Water hyacinth accumulated Cd and Cr best, Se and Cu at moderate levels, and was a poor accumulator of As and Ni. The highest levels of Cd found in shoots and roots were 371 and 6103 mg kg−1 dry wt., respectively, and those of Cr were 119 and 3951 mg kg−1 dry wt., respectively. Cadmium, Cr, Cu, Ni, and As were more highly accumulated in roots than in shoots. In contrast, Se was accumulated more in shoots than in roots at most external concentrations. Water hyacinth had high trace element bioconcentration factors when supplied with low external concentrations of all six elements, particularly Cd (highest BCF = 2150), Cr (1823), and Cu (595). Therefore, water hyacinth will be very efficient at phytoextracting trace elements from wastewater containing low concentrations of these elements. We conclude that water hyacinth is a promising candidate for phytoremediation of wastewater polluted with Cd, Cr, Cu, and Se.

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Pyrolysis conditions directly influence biochar properties and, consequently, influence the potential use of biochar. In this study, we evaluated the effects of different pyrolysis temperatures (450, 550, 650, 750, 850, and 950 °C) on the hydrogen potential, electrical conductivity, ash content, yield, volatile matter content, elemental analysis, Fourier-transform infrared spectroscopy results, X-ray diffraction results, scanning electron microscopy results, specific surface area, and micropore volume of eucalyptus wood-derived biochar. The degree of linear association between pyrolysis temperatures and biochar properties was examined using the Pearson correlation coefficient. The results showed a positive correlation of the pyrolysis temperature with the hydrogen potential value, electrical conductivity, and elemental carbon. There was a negative correlation of the pyrolysis temperature with the yield, volatile matter content, elemental oxygen, elemental hydrogen, surface area, aromaticity, hydrophilicity, and polarity indexes. The Fourier-transform infrared spectroscopy data indicated an increase in aromaticity and a decrease in the polarity of high-temperature biochar. The increased pyrolysis temperature caused the loss of cellulose and crystalline mineral components, as indicated by X-ray diffraction analysis and scanning electron microscopy images. These results indicated that changing the pyrolysis temperature enables the production of biochar from the same raw material with a wide range of physicochemical properties, which allows its use in various types of agricultural and environmental activities.

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The compounds (I)‐(IV) and (VII) are new natural products from the title species.

The main objective of this work was to evaluate the effects of ultrasound irradiation on the activity of a commercial amylase. A central composite design was carried out to assess the effects of temperature and pH on the enzyme activity in the presence and absence of ultrasound irradiation. The activation energy, the influence of treatment time as well as the substrate concentration on enzyme activity were also determined in the presence and absence of ultrasound irradiation. The results demonstrated that the effect of temperature was less pronounced in the presence of ultrasound, resulting in a decreasing of about 80% in the activation energy in comparison with the value obtained in the absence. The enzyme showed activities about 3 times higher for temperatures up to 40 °C in the presence of ultrasound. The pH negatively affected the activity in the presence of ultrasound, whereas in the absence a positive effect was verified. The ultrasound irradiation is a promising technology to be used in enzymatic reaction due to its positive effects on enzyme activity.

A rtemísia [Tanacetum parthenium (L.) Schultz.-Bip., sinonímia Chrysanthemum parthenium L. Bern.] (Asteraceae) é uma planta medicinal nativa no Sudeste Europeu e Ásia Menor, utilizada na profilaxia da enxaqueca. Apesar da origem européia, encontra-se bem estabelecida na América do Norte e do Sul e no Nordeste da África (Hendriks et al., 1996;Brown et al., 1999). A literatura etnobotânica registra o uso de suas flores e folhas, por via oral e local, no tratamento caseiro de muitas enfermidades como dores de cabeça, mal estar gástrico, diarréia, cóli-cas, reumatismo, câimbra e vermes (Lorenzi & Matos, 2002 (Abad et al., 1995; Berry, 1984; Figueiredo, 1998).Estudos recentes têm indicado que plantas de qualidade podem ser obtidas por meio de sistemas de reduzida irrigação (Morvant et al.,1998). A deficiên-cia de umidade altera vários processos bioquímicos e fisiológicos, e induz respostas metabólicas e fisiológicas como o fechamento estomático, declínio na taxa de crescimento, acúmulo de solutos e substâncias antioxidantes, e expressão de genes específicos de estresse (Steponkus, 1990;Singh-Sangwan et al., 1994). Algumas mudanças podem causar injúria às plantas, no entanto outras ocorrem enquanto a planta ajustase fisiologicamente ao estado de menor disponibilidade de água.Clorofila e carotenóides são os pigmentos biológicos e fotossintéticos mais abundantes no planeta. A perda de pigmentos durante estresse ambiental ou morte prematura é um indicador muito visível de eventos como doenças, aplicação de herbicidas, poluição ambiental, deficiência e toxicidade mineral, deficiência hídrica, extremos de temperatura, exposição a UV-B (Hendry & Price, 1993). Tem sido demonstrada a existên-cia de relação entre índice de intensidade da cor verde e teor de clorofila em várias espécies de plantas. O SPAD-502 é um equipamento, disponível atualmente no mercado, que determina o teor relativo de clorofila, medindo a transmissão de luz vermelha a 650 ηm, re-1 Trabalho executado com apoio do CNPq RESUMOPlantas de artemísia (Tanacetum parthenium L. Schultz-Bip.), cultivadas em vasos com substrato mantido na capacidade de campo, a 90%, a 70% e a 50% da capacidade de campo foram comparadas quanto à altura, acúmulo de massa fresca na parte aérea, teor relativo de clorofila e teor de prolina. O teor relativo de clorofila foi estimado por meio do clorofilômetro SPAD-502, enquanto o teor de prolina foi determinado por colorimetria. Verificou-se reduções de 16% na altura e de 22,5% no acúmulo de massa fresca nas plantas crescidas a 50% da capacidade de campo, em relação àquelas crescidas a 90% da capacidade de campo. O teor relativo de clorofila nas folhas, em quaisquer dos níveis hídricos, decresceu com o tempo, indicando tendência à senescência. Apesar da redução contínua nos níveis de clorofila, as plantas mantidas a 50% da capacidade de campo tiveram, durante todo o tempo acompanhado, teor relativo de clorofila cerca de 30% mais alto comparado às plantas mantidas a 90% da capacidade de campo. O teor de prolina também foi maior nessas ...