Photocatalytic decomposition of diclofenac potassium using silver-modified TiO(2) thin films

The effects of silver insertion on the TiO(2) photocatalytic activity for the degradation of diclofenac potassium were reported here. Techniques such as X-ray diffraction, scanning electron microscopy and UV-Vis spectroscopy were used to comprehend the relation between structure and properties of the silver-modified TiO(2), thin films obtained by the sol-gel method. The lattice parameters and the crystallinity of TiO(2) anatase phase were affected by inserted silver, and the film thickness increased about 4 nm for each 1 wt.% of silver inserted. The degradation of diclofenac potassium and by-products reached an efficiency of 4.6 mg(C) W(-1) when the material was modified with silver. Although the first step of degradation involves only the photochemical process related to the loss of the chlorine and hydrogen atoms. This cyclization reaction leads to the formation of intermediate, which degradation is facilitated by the modified material. (C) 2007 Elsevier B.V. All rights reserved.

Nutrient cycling in a RRIM 600 clone rubber plantation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Mineralogy and forms of potassium in red yellow latosol of a guava (Psidium guajava) tree orchard

A trial was conducted during 1994-95 to study the effect of potassium fertilization on a guava (Psidium guajava L.) culture for 3 years. The control plots (without K) showed fruit production and potassium exportation that did not agree with the levels obtained by chemical analysis of the soil. Physical, chemical, mineralogic and morphologic analyses were performed on the red yellow latosol to identify minerals able to supply potassium, with emphasis on the fact that guava trees have a considerably widespread root system. The results obtained confirmed the presence of minerals in this soil that can supply potassium to the trees through weathering. Feldspars were identified in the silt fraction and micas in the clay fraction by X-ray diffractometry. The determination of total potassium revealed that the silt fraction of the soil had the largest absolute amounts of potassium, followed by clay. However, in view of its greater content, clay was the fraction that contributed most to the total amounts of potassium detected.

Non-nutrient heavy metals in tomato plants cultivated in soil amended with biosolid and sugar-cane bagasse compost

In this study, non-nutrient heavy metal concentrations (Cd, Cr, Ni and Pb) were measured in composts during the composting process, in compost/Red-yellow Latosol mixtures, and in tomato plants. Composts were produced using sugar-cane bagasse, biosolids and cattle manure in the proportions 75-0-25, 75-12.5-12.5, 75-25-0, 50-50-0 or 0-100-0 (composts with 0, 12.5, 25, 50 and 100% biosolids). The composts were applied to the soil, in 6 treatments and a control (mineral fertilization). Control and the 0% biosolids treatments received inorganic nitrogen and all the treatments received the same amount of N, P and K. Tomato plants were cultivated in 24-L pots, in a green house in Jaboticabal, SP, Brazil. The experiment had a split plot design, in randomized blocks. Cadmium, Cr, Ni and Pb concentrations were determined during the composting process (7, 27, 57, 97 and 127 days after compost mounting), in soil (0 and 164 days after mixing) and plants. The samples were subjected to digestion with HNO 3, H2O2 and HCl and the metals were determined by AAS. Negative correlations were observed between Cd, Cr and Pb in the compost and Cd, Cr and Pb plant uptake, as well as Ni in the compost and Ni concentration in the plants. The concentrations of Cd, Cr, Ni and Pb increased during composting. Only Cd levels increased when compost was applied to the soil. The roots accumulated Cr, Ni and Pb, the stems and leaves, Cd and Ni and the fruits did not accumulate any of the metals studied. The composts with biosolids did not increase Cd, Cr, Ni and Pb uptake by plants.

Carbon isotope composition as a tool to control the quality of herbs and medicinal plants

Isotope screening is a simple test for determining the photosynthetic pathway used by plants. The scope of this work was to classify the photosynthetic type of some herbs and medicinal plants through studies of the carbon isotope composition (δ13C). Also, we propose the use of carbon isotope composition as a tool to control the quality of herbs and medicinal plants. For studies of δ13C, δ 13C‰ = [R (sample)/R (standard) - 1] × 10-3, dry leaves powdered in cryogenic mill were analyzed in a mass spectrometer coupled with an elemental analyzer for determining the ratio R = 13CO2/12CO2. In investigation of δ13C of 55 species, 23 botanical families, and 44 species possessed a C3 photosynthetic type. Six species found among the botanical families Euphorbiaceae and Poaceae were C4 plants, and 5 species found among the botanical families Agavaceae, Euphorbiaceae, and Liliaceae possessed CAM-type photosynthesis. Carbon isotope composition of plants can be used as quality control of herbs and medicinal plants, allowing the identification of frauds or contaminations. Also, the information about the photosynthetic type found for these plants can help in introducing and cultivating exotic and wild herbs and medicinal plants.

Carbon isotope composition as a tool for quality control of herbs, spices and medicinal plants

Isotope screening is a simple and cheap test for determining the photosynthetic pathway used by plants. The scope of this work was to classify the photosynthetic type of Melissa officinalis L. and Cymbopogon citratus [DC.] Stapf, through studies of the carbon isotope composition (δ13 C), and we are proposing the use of carbon isotope composition results as a tool to control the quality of medicinal plants. For studies of δ 13C (13 C% = [R (sample)/R (standard) - 1] × 10 -3), dried, powdered leaves were analyzed in a mass spectrometer coupled with an elemental analyzer for determining the ratio R (R = 13CO2/12CO2). As results, M. officinalis presented a C3 photosynthetic type, and C. citratus presented a C4 photosynthetic type. The carbon isotope composition from this study can be used as quality control of M. officinalis adulterants.

Cloreto de potássio revestido em efeito residual no feijoeiro de inverno irrigado na região de cerrado

In order to maintain the nutrients available to plants have been studied controlled release fertilizers. In this context, the objective was to evaluate the residual effect of doses of potassium chloride, coated or not, applied in the corn crop, regarding the crop components and grains yield of irrigated winter common bean, cultivated in followed, in Cerrado region. The experiment was conducted in Selvíria - MS, Brazil, 51°22- west longitude and 20°22- south latitude, in a clayey Oxisol, in 2009 and 2010. A randomized block design with four repetitions was used, disposed in a factorial scheme 4 x 2, being: four K2O doses (0, 40, 80 and 120 kg ha-1) and two potassium sources (potassium chloride and coated potassium chloride by polymers) applied at sowing in the corn crop. The coated potassium chloride by polymers have the same residual effect as conventional KCl, because it provides results similar for the K and chlorophyll leaf contents, crop components and grains yield of winter common bean irrigated. The increment of potassium doses in the previous crop (corn) have residual effect, because it influenced positively the number of grains per plant in 2009 and increased linearly the chlorophyll leaf content and the grains yield of winter common bean irrigated in 2010, regardless of the source used for K.

Doses de N e K aplicadas via fertirrigação e espaçamento entre plantas influenciando o desenvolvimento, a produtividade e as relações hídricas em melancieira com e sem sementes

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Níveis de potássio em solução nutritiva, desenvolvimento de plantas e a produção de óleo essencial de mentha piperita L

Pós-graduação em Agronomia (Horticultura) - FCA

Crescimento de plantas de Corymbia citriodora (Hook.) K. D. Hill & L. A. S. Johnson sob diferentes doses de potássio e níveis de umidade do solo

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Crescimento e acúmulo de nutrientes do meloeiro rendilhado cultivado em substrato

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação de métodos e extratores químicos na determinação de silício disponível em solos cultivados com cana-de-açúcar

Pós-graduação em Agronomia (Energia na Agricultura) - FCA

Densidades populacionais e épocas de plantio na cultura da couve-flor, híbrido Verona 284

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Murcha-de-curtobacterium do feijoeiro: ocorrência em Santa Catarina, comportamento de genótipos e efeito de nitrogênio e potássio

Pós-graduação em Agronomia (Proteção de Plantas) - FCA

Respostas fisiológicas de genótipos de Eucalyptus grandis x E. urophylla à disponibilidade hídrica e adubação potássica

Conduziu-se este trabalho, com o objetivo de estudar as respostas fisiológicas de cinco genótipos de eucalipto à disponibilidade hídrica e adubação potássica. As mudas foram plantadas em vasos preenchidos com sete litros de um Neossolo Quartzarênico, com baixo teor natural de potássio (0,2 mmol c.dm-3 K), e submetidas a dois regimes de irrigação (RI1 - diário e RI2 - irrigação suspensa até o aparecimento de sintomas iniciais de murcha), sem (K0) e com suprimento de potássio (K1 - 200 mg.dm-3 K2O), em casa de vegetação. Avaliou-se a taxa fotossintética (A), condutância estomática (gs), transpiração (E), índice de conteúdo de clorofila (ICC), conteúdo relativo de água (CRA), eficiência fotoquímica (Fv/Fm), eficiência intrínseca (EUAintr) e instantânea no uso da água (EUAinst) e potencial hídrico foliar (Ψf). O experimento foi estabelecido no delineamento de blocos ao acaso, em esquema fatorial 5 x 2 x 2 (5 genótipos, 2 regimes de irrigação e 2 níveis de adubação potássica), com cinco repetições. À exceção da eficiência fotoquímica, as demais características apresentaram alterações significativas no regime RI2, com redução nos valores de A, gs e E e aumento em ICC e EUAinst. O suprimento de potássio nas plantas do RI2 proporcionou maiores valores de A, gs, E e CRA. Dos genótipos avaliados, o G1 é o mais resistente e o G2 o mais sensível à deficiência hídrica. Conclui-se que a adubação potássica pode amenizar os efeitos negativos da deficiência hídrica nos estádios iniciais de crescimento de eucalipto.