O presente trabalho procura dar continuidade a uma das linhas de pesquisa desenvolvida pelo Grupo de Química Analítica do Instituto de Química da Universidade de são Paulo: o estudo da formação de complexos. O sistema Hg(II) / S2O2-3 foi analisado potenciometricamente, com a finalidade de identificar o número de complexos formados, assim como estimar as constantes de estabilidade envolvidas no fenônemo de complexação. Tal equilíbrio foi levado a termo a 25,0 ± 0,1°C, e força iônica 2,00M, sendo detectados quatro espécies complexas. O modelo matemático que melhor se ajustou aos dados experimentais fornecidos pelo sistema, conta com os seguintes valores para as constantes globais de formação: β1 1 = x 1024 M-1 (valor atribuído) β2 = (8,0 ± 2,8) x 1027 M-2 β3 = (1,71 ± 0,03) x 1030 M-3 β4 = (3,07 ± 0,77) x 1030 M-4. Na região de baixa concentração analítica de ligante, 5mM, o acesso experimental foi limitado pela precipitação de sulfeto mercúrico sendo impossível obter informaçôes sobre a primeira espécie. O comportamento do mercúrio no sistema Hg(II) / S2O2-3 foi estudado de uma forma mais abrangente, sendo estendido ao meio não complexante, onde o equilíbrio de dismutação do cátion mercuroso governa. Nas mesmas condições de temperatura e força iônica anteriores, foram obtidos alguns parâmetros desse equilibrio, a saber: - potenciais formais de eletrodo: Eo\'Hg(I) / Hg(O) = ( 0,456 ± 0,014 ) V Eo\'Hg(II) / Hg(O) = ( 0,559 ± 0,0016) V Eo\'Hg(III) / Hg(I) = ( 0, 6625 ± 0,0023 ) V - constante do equilibrio heterogêneo: Qp (potenciométrica) = (3 ± 1) x 103 Adicionalmente, foram realizados estudos eletrogravimétricos sobre o mecanismo de oxidação coulométrica do mercúrio metálico, em diversos eletrólitos suporte, merecendo destaque a estabilização do Hg(I) por cloreto, e do Hg (II) por tiossulfato, mostrando que a transferência eletrônica é um processo por etapas. Complementando o estudo do sistema, a potencialidade análitica do tiossulfato na determinação dos cátions do mercúrio foi confirmada em titulações potenciométricas. / The present work belongs to one of the topics developed by the Analytical Chemistry Group in the Chemistry Institute of the são Paulo University: the study of complex formation equilibrium. The Hg(II)/S2O2-3 system was potentiometrically analysed with the purpose of identifying the number of formed complexes as well as computing their stability constants. Such equilibria study was performed at a 25.0 ± 0.1ºC temperature and 2.00 M ionic strengh, mantained with NaClO4. Four stepwise complexes have been detected by a calculus procedure based on non-linear regression. The best formation constants set is: β1 1 = x 1024 M-1 (arbitrary value) β 2 = (8,0 ± 2,8) x 1027 M-2 β3 = (1,71 ± 0,03) x 1030 M-3 β4 = (3,07 ± 0,77) x 1030 M-3. At lower ligand concentration, nearly 5mM, the experimental access was limited by the mercuric sulphide precipitation, being impossible to achieve data on the first specie. The mercury performance in the Hg(II)/S2O2-3 system was more widely studied with concern to the non-complexing media, where the disrnutation of mercurous cation leads. With the same previous temperature and ionic stengh conditions, some equilibria parameters have been determined: - electrode potentials: Eo\'Hg(I) / Hg(O) = ( 0,456 ± 0,014 ) V Eo\'Hg(II) / Hg(O) = ( 0,559 ± 0,0016) V Eo\'Hg(III) / Hg(I) = ( 0, 6625 ± 0,0023) V - heterogeneous equilibria constant: Qp = (3 ± 1) x 103. Electrogravimetric studies about the coulometric oxidation mecanism of metallic mercury have also been executed. The oxidation was carried out at several suporting electrolites, regarding the Hg(II) stabilization by the tiossulphate anion, and the Hg(I) by chloride, showing that the electrochemical transfer occurs in a step by step process. In addition to system study, the analytical potentiality of the tiossulphate on the determination of mercury cationic species was confirmed by potentiometric titulations.

Neste trabalho foi avaliado a seletividade de reações biocatalisadas por fungos basidiomicetos frente a compostos bifuncionalizados com os grupos cetona e seleneto (1-2) ou cetona e sulfeto (3-4). Os compostos 1-4 foram sintetizados de acordo com metodologias descritas na literatura. Na síntese dos padrões racêmicos dos β-hidróxi-selenetos 1a-2a e β-hidróxi-sulfetos 3a-4a observou-se que a redução química utilizando NaBH4 levou a formação preferencial dos estereoisômeros cis-(1a-4a). Enquanto que a redução promovida na utilização dos fungos basidiomicetos levou a formação preferencial do estereoisômero trans-(1a-4a). Desta forma duas metodologias complementares para a preparação de β-hidróxi-selenetos e β-hidróxi-sulfetos foram estabelecidas. Cinco linhagens destes fungos (Irpex lacteus CCB 196, Trametes rigida CCB 285, Pycnoporus sanguineus CCB 501, Trametes byssogenum CCB 203, Trametes versicolor CCB 202 ) foram testadas visando à obtenção de β-hidróxi-selenetos (1a-2a) e β-hidróxi-sulfetos (3a-4a) na forma enantiomericamente pura ou enriquecida. Um estudo qualitativo indicou que o fungo Trametes rigida CCB 285 apresentou alta seletividade frente aos compostos utilizados levando aos produtos cis-(1a-4a) e trans-(1a-4a) com elevados valores de excessos enantioméricos (e.e. 99 %). Posteriormente, um estudo quantitativo permitiu o isolamento dos produtos, a determinação dos rendimentos isolados e também a configuração absoluta para os compostos isolados. Na segunda parte deste trabalho avaliou-se a aplicação de fungos Aspegillus terreus em reações de desmetilação/desalquilação de aminas terciárias. Os resultados obtidos indicam que os estes fungos apresentam grande potencial para reações de desmetilação de aminas terciárias aromáticas, sendo que as reações conduzidas em meio neutro (pH = 7) levaram aos produtos desmetilados com bons valores de conversão. No entanto, não foram observadas reações de desalquilação com grupos etila nas condições utilizadas. / In this work was considered the selectivity of reactions biocatalysted by basidiomycetes fungi with bifuncionalized compounds with ketone and selenide groups (1-2) or ketone and thio groups (3-4). The compounds 1-4 were prepared in according with methodologies from literature. During the synthesis of standard racemic β-hydroxyselenides 1a-4a and β-hydroxysulfides 3a-4a we noticed that chemical reduction using NaBH4 led to the preferential formation of the cis-(1a-4a) isomers. On the other hand, the bioreduction promoted by basidiomycetes fungi led to the preferential formation of trans-(1a-4a) isomers. Therefore, two complementary methodologies for preparation of β-hydroxyselenides and β-hydroxysulfides were established. Five strains of basidiomycetes fungi (Irpex lacteus CCB 196, Trametes rigida CCB 285, Pycnoporus sanguineus CCB 501, Trametes byssogenum CCB 203, Trametes versicolor CCB 202) were examined to aim at the preparation of β-hydroxyselenides and β-hydroxysulfides on the enantiomerically pure form. A qualitative study indicated that cells of T. rigida CCB 285 showed high selectivity led to the products cis-(1a-4a) and trans-(1a-4a) in high enantiomeric excess (ca 99 %). After that, a quantitative study allowed us to determine the isolated yields and the absolute configuration for the compounds cis-(1a-4a) and trans-(1a-4a). In the second part of this work was considered the application of Aspergillus terreus fungi in demethylation/dealkylation reactions by tertiary amines. The results indicated that those fungi showed a big potencial for demethylation reaction of aromatic tertiary amines. The reaction done on the pH = 7 led to the demethylated products with good values of conversion. Dealkylation reactions were not observed.

A monoetanolamina (MEA) é um composto bifuncional pertencente à classe dos amino-álcoois, muito utilizado em processos industriais envolvendo a remoção de gases ácidos como SO2 , CO2 e H2S. A resina Amberlite XAD-7 é uma resina não-iônica de polaridade intermediária muito utilizada em procedimentos de pré-concentração de compostos orgânicos e íons metálicos. Neste trabalho, estudou-se a interação entre a superfície da resina XAD-7 e a MEA. Massas conhecidas da resina foram colocadas em contato com soluções de MEA em concentrações conhecidas, sob agitação durante certo intervalo de tempo. A quantidade de MEA adsorvida foi calculada considerando-se a diferença entre a concentração inicial e a concentração remanescente no sobrenadante, ambas obtidas a partir de medidas de absorbância, com utilização da reação de Berthelot modificada. Modelos cinéticos de pseudo-primeira e -segunda ordens, além do modelo de difusão intra-partícula, foram aplicados aos dados experimentais obtidos no estudo cinético. Entre estes modelos aplicados, o de pseudo-segunda ordem apresentou excelente ajuste aos dados experimentais. O estudo realizado em um determinado tempo de contato e variando-se a concentração inicial de MEA forneceu resultados experimentais que foram aplicados a três modelos de isotermas (Langmuir, Freundlich e Dubinin-Radushkevich). Destes ajustes, que mostraram excelente concordância, foram obtidos diferentes parâmetros termodinâmicos que definiram algumas características do processo de adsorção. Finalmente, estudos preliminares evidenciaram a retenção de SO32- na superfície da resina XAD-7 modificada com MEA, mostrando a possibilidade da utilização da XAD- 2 7/MEA para extração de SO32- presente em soluções ou de SO2 recolhido em solução alcalina. / Monoethanolamine (MEA) is a bifunctional compound which belongs to the amino- alcohol group, and it is widely used in industrial \"sweetening process\", which is based on the acidic gas (such as SO2 , CO2 and H2S) absorption. Amberlite XAD-7 is a non-polar resin with an intermediate polarity used to pre-concentrate organic compounds and transition metals. In this work, the interaction between the resin surface and MEA was studied. Known amounts of the resin were kept in contact with aqueous solutions of MEA and shaked under a constant rotation and during some defined intervals of time. The amount of adsorbed MEA was calculated as the difference between the initial concentration and remained concentration in the supernatant solution, which was determined applying the Berthelot´s reaction and the spectrophotometry. Kinetic models of pseudo-first and -second orders and intra-particle diffusion model were applied on experimental data collected from the kinetic study. Among these methods, the pseudo-second order model fulled fit on those experimental data. The experiments carried out under a constant time, but by changing the initial MEA concentration, led to other experimental data which were applied to three different isotherm models (Langmuir, Freundlich e Dubinin-Radushkevich). Each model showed a good fit, and for each one, different thermodynamic parameters were calculated and used to describe some adsorption characteristics. Finally, preliminary studies on the retention of SO32- onto the resin surface, previously modified with MEA, showed the possibility to extract SO32- found in aqueous solutions or SO2 recovered in alkaline media.

A remoção de compostos sulfurosos (sulfeto/sulfato) de águas residuárias tem grande importância para a saúde humana e para o ambiente. A biorremediação desses compostos, através da utilização de bactérias fototróficas anoxigênicas apresenta-se como alternativa viável ecológica e economicamente. Neste projeto de pesquisa realizaram-se ensaios em reatores em batelada expostos à iluminação fluorescente, com a finalidade de avaliar a utilização de sulfeto por cultura enriquecida de sulfubactérias fototróficas verdes, proveniente de sedimento de lagoa de estabilização. A avaliação da utilização de sulfeto e os resultados da cinética de crescimento da cultura visam a possibilidade de aplicação das bactérias fototróficas anoxigênicas no tratamento de águas residuárias. Na avaliação cinética de crescimento da cultura enriquecida de sulfubactérias fototróficas verdes foi verificado diminuição na velocidade de crescimento de 0,0346 h-1 para 0,0035 h-1 com o aumento da concentração inicial de sulfeto de 11,4 para 529,6 mg-S/L, respectivamente. O tempo de geração apresentou comportamento crescente com valores iguais a 19,98 h e 119,18 h, respectivamente. Os valores do coeficiente de conversão de sulfeto relativo ao crescimento de microrganismos (Yx/s), apresentaram diminuição progressiva com o aumento da concentração inicial de sulfeto, sendo esta queda mais acentuada no intervalo de concentrações de 40,5 a 147,2 mg-S/L. / The removal of sulphur compounds (sulfide/sulfate) from wastewaters is very important for human and for the environmental. The bioremediation of these compounds, applying anoxigenic phototrophic bacteria has been presented as a possible alternative. The aim of this work is to evaluate the utilization of sulfide by the enrichment of green sulphur bacteria proceeding from stabilization pond sediment, through the realization of batch reactors assays, which are exposed to fluorescent ilumination. The determination of the sulfide utilization and the results of the kinetic growth were done to clarify the possibility of the application of anoxigenic phototrophic bacteria in the wasterwater systems. In kinetic experiments it was observed that the specific rate of bacterial growth changed from 0.0346 h-1 to 0.0035 h-1. Then the initial sulfide concentration was increased form 11.4 mg-S/L to 529.6 mg-L. The doubling time showed an increase from 19.98 h to 119.18 h. The sulfide conversion to microorganism biomass (Yx/s) progressively decrease with the increase of sulfide concentration. Such a decrease was higher in between sulfide concentrations of 40.5 mg-S/L to 147.2 mg-S/L.

A baixa disponibilidade de nutrientes na exploração da pastagem é um dos principais fatores que interfere tanto na produtividade como na qualidade da forrageira. O presente trabalho objetivou avaliar os efeitos de combinações de doses de nitrogênio com doses de enxofre para a Brachiaria brizantha cv. Marandu, cultivada em solução nutritiva, utilizando sílica como substrato, em um experimento conduzido em casa-de-vegetação, em Piracicaba-SP, no período de setembro a dezembro de 2001. Utilizou-se um esquema fatorial 5 2 fracionado, com 13 combinações assim definidas, para nitrogênio e enxofre na solução nutritiva: 14 e 3,2; 14 e 32; 14 e 80; 126 e 12,8; 126 e 64; 210 e 3,2; 210 e 32; 210 e 80; 336 e 12,8; 336 e 64; 462 e 3,2; 462 e 32 e 462 e 80 mg L -1 , as quais foram distribuídas segundo delineamento estatístico de blocos ao acaso, com quatro repetições. Foram realizados dois cortes nas plantas, ocasiões em que se separou a parte aérea em folhas emergentes, lâminas de folhas recém-expandidas, lâminas de folhas maduras e colmos mais bainhas. Após o segundo corte as raízes foram separadas do substrato e tiveram o comprimento e a superfície avaliados. Os resultados demonstraram que a interação entre as doses de nitrogênio e enxofre foi significativa para o número total de perfilhos, o número total de folhas expandidas, o teor de clorofila, a área foliar, a produção de massa seca da parte aérea, a concentração de nitrogênio em folhas emergentes e nas raízes, a concentração de enxofre e a relação N:S em folhas emergentes, lâminas de folhas recém-expandidas e lâminas de folhas maduras em um ou ambos os cortes. Para a atividade da redutase do nitrato não foi observada significância quer para a interação entre as doses de nitrogênio e enxofre, quer para as doses individuais de nitrogênio e enxofre. A máxima concentração de nitrogênio (31,6 g kg -1 ) nos componentes do capim foi observada nas folhas emergentes na dose de nitrogênio de 462 mg L -1 por ocasião do primeiro corte. Para o enxofre a máxima concentração (2,8 g kg -1 ) foi observada nos colmos+bainhas na dose de nitrogênio de 14 mg L -1 , à época do segundo corte. A relação N:S nas lâminas de folhas recém-expandidas variou de 2,8:1 a 37,2:1 sendo o mínimo observado com muito baixo suprimento de nitrogênio e o máximo dessa relação ocorrendo com fornecimento de alta dose de nitrogênio combinada com baixa disponibilidade de enxofre. É necessário suprir enxofre quando se incrementa a disponibilidade de nitrogênio para o capim-Marandu. / The low availability of nutrients in the exploration of the grassland is one of the main factors to interfere in grass productivity and quality. This experiment had the objectives of evaluating the effects of combinations of nitrogen and sulphur rates to Brachiaria brizantha cv. Marandu, grown in nutrient solution, using ground quartz as substrate. The experiment was carried out in a greenhouse located Piracicaba, São Paulo State from September to December of 2001. It was a incomplete factorial set in radomized blocks with four replications, and the 13 combinations of nitrogen and sulphur were: 14 and 3.2; 14 and 32; 14 and 80; 126 and 12.8; 126 and 64; 210 and 3.2; 210 and 32; 210 and 80; 336 and 12.8; 336 and 64; 462 and 3.2; 462 and 32; 462 and 80 mg L -1 . Forage grass was harvested twice and in each one plant tops were separated in emergent leaves, lamina of recently expanded leaves, lamina of mature leaves and culms plus sheaths. After the second harvest roots were taken from the substrate and had the lenght and surface determined. The results showed significant interaction between nitrogen and sulphur rates for the number of total tillers, number of total expanded leaves, chlorophyll concentration (SPAD), leaf area, plant tops dry weight, nitrogen concentration in emergent leaves and in the roots, and sulphur concentration and N:S ratio in emergent leaves, lamina of recently expanded leaves and in lamina of mature leaves in the Marandu grass at one or both harvests. Significant interaction between nitrogen and sulphur rates in the first harvest in the dry matter yield of the top parts. It was not significant either the interaction between nitrogen and sulphur rates or nitrogen and sulphur rate. Maximum nitrogen concentration (31.6 g kg -1) was found in emergent leaves at the nitrogen rate of 462 mg L -1, in the first harvest. Sulphur concentration was maximum in the culms plus sheaths (2.8 g kg -1) on nitrogen rate of 14 mg L -1 at the second harvest. The N:S ratio in the lamina of recently expanded leaves ranged from 2.8:1 to 37.2:1, with the minimum value observed with the very low nitrogen supply and the maximum with high nitrogen rate combined with low sulphur availability. There is a need of sulphur supply when nitrogen is made highly available to Marandu grass.

O nitrogênio tem sido indispensável na formação, manutenção e recuperação de pastagens e seu efeito tem mostrado ser dependente do suprimento de enxofre, pela relação desses nutrientes no metabolismo vegetal. Objetivou-se: a) estudar combinações de doses de nitrogênio e de enxofre em solo suportando capim-Braquiária (Brachiaria decumbens) em degradação; b) avaliar o efeito do nitrogênio e do enxofre na eficiência no uso de água pelo capim; c) caracterizar as formas de nitrogênio e de enxofre no solo, antes, durante e após as adubações desses nutrientes; d) determinar a influência das combinações desses nutrientes em características nutricionais e produtivas do capim em recuperação. Coletaram-se amostras com plantas + solo em cilindros de 15 cm de diâmetro e 20 cm de profundidade num Neossolo Quartzarênico de uma pastagem em degradação. Utilizaram-se cinco doses de nitrogênio (0; 100; 200; 300 e 400 mg dm-3) e cinco doses de enxofre (0; 10; 20; 30 e 40 mg dm-3), combinadas em estudo de superfície de resposta baseado em desenho experimental composto central modificado de um fatorial 52 fracionado. Realizaram-se três cortes nas plantas com intervalos regulares de 30 dias. O fornecimento simultâneo de nitrogênio e enxofre na adubação aumentou a área foliar e a produção de massa seca, o número de perfilhos e melhorou a eficiência no uso de água pelo capim. A adubação com nitrogênio teve efeito isolado para o número de perfilhos e produção de massa seca no segundo e no terceiro crescimentos. O número de folhas foi influenciado pelas doses de nitrogênio e de enxofre de forma isolada, no primeiro crescimento e pelas doses de nitrogênio no segundo e no terceiro crescimentos. As relações entre as doses de nitrogênio e as de enxofre para as máximas produções foram de maneira geral em torno de 10:1. A adubação nitrogenada resultou em aumento na produção de massa, o comprimento e a superfície das raízes. O valor SPAD dependeu da combinação de doses de nitrogênio e de enxofre apenas no primeiro crescimento e teve efeito do nitrogênio no segundo e no terceiro crescimentos. As concentrações de nitrogênio e de enxofre no capim atingiram máximos valores nas doses mais elevadas. A baixa relação N:S de 7:1 no capim na não aplicação de nitrogênio indicou maior demanda de nitrogênio do que de enxofre. A interação entre as doses de nitrogênio e de enxofre não foi significativa para as características químicas avaliadas no solo. O pH do solo diminuiu quando o nitrogênio foi aplicado. A matéria orgânica no solo não variou após três períodos de crescimento do capim. A adubação com nitrato de amônio aumentou os teores de nitrogênio total, nitrogênio nítrico e nitrogênio amoniacal no solo. O teor de nitrogênio na forma amoniacal foi superior ao da forma nítrica no solo. A adubação com sulfato de cálcio aumentou os teores de enxofre total e de enxofre sulfato no solo. A aplicação principalmente de nitrogênio, mas também de enxofre, influenciou o estádio nutricional do capim-Braquiária e conseqüentemente a sua recuperação. / Nitrogen is required for pastures establishment, maintenance and production recovery, and its effect has depended on sulphur supply, for the relationship between these nutrients in plant metabolism. The objectives were: a) to study the combinations between nitrogen and sulphur rates in soil with Signal grass (Brachiaria decumbens) under degradation; b) to evaluate the effect of nitrogen and sulphur on the water use efficiency by grass; c) to determine the nitrogen and sulphur in the soil, before, in the course of the combinations between these nutrients on productive and nutritional characteristics of the recovering grass. Samples of plants plus soil were collected in cylinders of 15 cm diameter and 20 cm depth from an Entisol with a degrading pasture. Five rates of nitrogen (0; 100; 200; 300 and 400 mg dm-3) were combined with five rates of sulphur (0; 10; 20; 30 and 40 mg dm-3) in a response surface methodology based on a central composite design modified from a fractional 52 factorial. Three harvests were done after each 30 days of plants growth. The supply of nitrogen and sulphur together increased Signal grass leaf area, dry matter yield, number of tillers and improved the water use efficiency by the grass. Nitrogen rates had effects on the number of tillers and dry matter yield at the second and third harvests of the grass. The number of leaves was changed by both nitrogen and sulphur rates at the first growth, and by nitrogen rates at the second and third growths. Maximum dry matter yields were attained when nitrogen and sulphur rates were at about 10:1 ratio. Nitrogen supply affected grass roots by increasing roots dry weight, length and surface. SPAD values changed with combined rates of nitrogen and sulphur at the first growth, and with nitrogen rates at the second and third growths. Nitrogen and sulphur concentrations were at maximum when maximum rates of these nutrients were applied. The low 7:1 N:S ratio in the grass with no nitrogen supply suggested higher demand for nitrogen than sulphur. The interaction between nitrogen and sulphur rates was not significant for the evaluated soil chemical parameters. Soil pH decreased when nitrogen was applied. Soil organic matter content did not change after the growth periods of the grass. Ammonium nitrate supply resulted in increases in total nitrogen, nitrate and ammonium in the soil. Ammonium concentration in the soil was higher than nitrate. Calcium sulphate application resulted in increases in total sulphur and sulphate-sulphur in the soil. The application of mainly nitrogen, but also of sulphur, affected the nutritional status of Signal grass, and its recovery.

Les cultures intermédiaires multi-services (CIMS) implantées en interculture entre deux cultures de rente permettent de produire de nombreux services écosystémiques. Parmi les familles d’espèces utilisées comme CIMS, les crucifères réduisent efficacement la lixiviation de nitrate et de sulfate en captant l’azote (N) et le soufre (S) minéral du sol (services de piège à N et à S). Les crucifères ont aussi la capacité de contrôler les pathogènes via des composés biocides issus de l’hydrolyse de métabolites secondaires appelés glucosinolates (GSL). L’objectif de nos travaux de recherche est d’évaluer les performances en termes de services écosystémiques liés à l’azote, au soufre et au potentiel de bio-contrôle d’une grande diversité de mélanges bispécifiques de crucifères et de légumineuses en comparaison aux CIMS pures. Nous avons réalisé des expérimentations sur 2 sites contrastés (région de Toulouse et Orléans, France) et sur 2 années pour tester les performances de mélanges crucifère-légumineuse en comparaison aux espèces pures. Les espèces testées sont i) pour les crucifères : colza, moutarde blanche, moutarde brune, moutarde éthiopienne, navet, navette, radis, roquette, et ii) pour les légumineuses : trèfle Egyptien, trèfle incarnat, vesce commune, vesce pourpre, vesce velue, pois, soja, féverole et lupin blanc. Nos travaux de recherche montrent que les mélanges crucifère-légumineuse peuvent produire simultanément divers services écosystémiques avec un haut niveau d’expression, allant de 2/3 (production de GSL, engrais vert à N et S), à quasiment 100% (piège à N et S) du service produit par la famille d’espèce pure la plus performante. La concentration et les types de GSL ne changeant pas en mélanges, les interactions des crucifères avec leurs pathogènes restent identiques. Via une revue de littérature nous concluons également que le service de bio-contrôle des cultures pures de crucifères peut être maintenu en mélanges crucifère-légumineuse sur une grande diversité de pathogènes et adventices tout en réduisant les potentiels dis-services sur les auxiliaires et sur le cycle de l’azote. / Multi-services cover crops (MSCC) grown during fallow period between two cash crops provide various ecosystem services. Among species used as MSCC, crucifers can efficiently prevent nitrate and sulphate leaching by catching residual soil mineral nitrogen (N) and sulphur (S) afterthe preceding cash crop (N and S catch crop services). Crucifers also have a unique capacity to suppress pathogens due to the biocidal hydrolysis products of endogenous secondary metabolites called glucosinolates (GSL). The aim of our study was to assess the provision of various ecosystem services linked to N, S cycles and biocontrol potential for a wide range of bispecific crucifer-legume mixtures in comparison to sole cover crops of legume and crucifer. We carried out experiments in 2 contrasted sites (Toulouse and Orléans regions, France) during 2 years in order to assess these services and the compatibility of various bi-specific crucifer-legume mixtures. We tested a great diversity of species, such as i) crucifers : rape, white mustard, Indian mustard, Ethiopian mustard, turnip, turnip rape, radish and rocket, and ii) legumes: Egyptian clover, crimson clover, common vetch, purple vetch, hairy vetch, pea, soya bean, faba bean, and white lupin. Our study demonstrated that crucifer-legume mixtures can provide and mutualize various ecosystem services by reaching from 2 thirds (GSL production, S and N green manure) to the same level ofservice (N and S catch crop) than the best sole family of species. GSL profile and concentration did not change in mixtures meaning that crucifer-pests interactions were identical. Through a literature review we also illustrated that biocontrol services of crucifers could be largely maintained in crucifer-legume mixtures for a wide range of pathogens and weeds while reducing potential disservices on beneficials and increasing N related service

The effects of crop load and berry exposure on the composition of Marlborough Sauvignon blanc grapes and wine from the Brancott vineyard, Blenheim, were explored. Commercially grown, 2-cane and 4-cane Sauvignon blanc vines were used with a row orientation of north-south. Two exposure treatments were imposed in the following manner: complete leaf removal was undertaken in the fruit zone and 50% shade cloth was erected to give a uniform shading treatment to half the trial vines. Weekly thirty-berry and whole bunch samples were taken from each of the 32 plots with the exception of the veraison period when two samples per week were taken. Vine vigour was assessed using pruning and leaf area per vine data. Harvest occurred on different dates for 2-cane and 4-cane pruned vines so that fruit attained from both treatments had similar °Brix. Fruit was processed at the Lincoln University winery. Must analysis and wine analysis were undertaken. As expected, 4-cane vines had almost double the yield of 2-cane vines. Higher crop load significantly reduced leaf area per shoot and shoot thickness. Lower leaf area to fruit ratio for 4-cane berries resulted in delayed onset of veraison and slowed the rate of sugar accumulation. Crop load, which limited leaf area to fruit ratio, appeared to be the dominant factor in determining timing of grape physiological ripeness as expressed by °Brix over other factors such as fruit exposure. Malic acid, tartaric acid, IPMP (iso-propylmethoxypyrazine) and IBMP (iso-butyl-methoxypyrazine) were lower at equivalent °Brix in 4-cane compared with 2-cane berries. Significantly higher concentrations of quercetin were found in exposed compared to shaded berries. Must analysis showed a significant influence of crop load on berry titratable acidity and pH, reflecting berry ripening results. Exposure significantly increased the concentrations of nitrogenous compounds in 4-cane must yet showed no influence on 2-cane must. After wine processing lower malic acid concentrations in wines made from 100% exposed fruit became evident in lower wine titratable acidity but showed no influence on wine pH. Bentonite addition to wines had a small but statistically significant influence on wine by reducing pH, titratable acidity and alcohol. Bound sulphur concentrations were significantly higher in 4-cane versus 2-cane wines. At harvest, methoxypyrazine levels in grapes and wines were very low; IBMP concentrations where significantly lower than those normally found in Sauvignon blanc wines from Marlborough. This was attributed to the absence of basal leaves from the shoots of ripening berries. The results suggest that leaf area to fruit ratio is a powerful determinant of grape and wine quality.

<p>Since the start of the industrialisation, the deposition of nitrogen and sulphur and the atmospheric concentrations of greenhouse gases have increased. The main objectives of this study were to find how these changes in climate and deposition can change the vegetation of mire ecosystems and the growth of <i>Sphagnum</i>species. Two main approaches were applied: re-investigated of two mires previously investigated 40-50 years ago and experiment manipulations. </p><p>The plant species diversity had decreased on one of the two re-investigated mires (Skattlösbergs Stormosse; central Sweden), but the total number of species was unchanged on the other (Åkhultmyren; southern Sweden). On Skattlösbergs Stormosse, an acidification was found in the high pH areas, coinciding with reduction in rich fen species. At Åkhultmyren, there was a similar reduction in pH, but the changes in the plant composition also indicated increased nutrient levels and a drier mire surface. Therwere large changes in species composition on Åkhultmyren. For instance <i>Scheuchzeria palustris</i> had disappeared from the investigated area. Further, the cover of Scots pine (<i>Pinusylvestris</i>) had increased, which can be explained by a changed ground-water table regime. Monitoring of pines growing on a bog over a ten-year period showed that pines growing higher above the ground-war table had higher survival than lower-growing pines.</p><p>Experimental addition of nitrogen during 3-4 years reduced <i>Sphagnum </i>growth in bogs and poor fens repressenting a wide range of ambient nitrogen deposition. A changed interspecific competitive relation was found between <i>S. lindberg</i>and <i>S. balticum</i> when increasing nitrogen influx, but the competitive relations between two hummock-growing species pairs did not change in a three-year nitrogen fertilization study. Sulphur additiodid not affect the production or length increment in <i>S. balticum</i>. An increased temperature reduced <i>Sphagnum </i>growth, but there were no indications of altered competitive relationshipbetween hummock and hollow inhabiting <i>Sphagnum </i>species in a four-year experiment.</p>

In dieser Arbeit wurde das reaktive Anlassen von dünnen Kupfer-Indium-Schichten in elementarem Schwefel mittels energiedispersiver Röntgenbeugung untersucht. Durch die simultane Aufnahme der Röntgenspektren und der Messung der diffusen Reflexion von Laserlicht der Wellenlänge 635 nm an der Oberfläche der Probe während des Schichtwachstums von CuInS<SUB>2</SUB> konnte eine Methode zur Prozesskontrolle für ein Herstellungsverfahren von CuInS<SUB>2</SUB> etabliert werden. <br><br>Die Bildung von CuInS<SUB>2</SUB> aus Kupfer-Indium-Vorläuferschichten wird dominiert von Umwandlungen der intermetallischen Phasen. CuInS<SUB>2</SUB> wächst innerhalb der Aufheizperiode ab einer Temperatur von ca. 200°C aus der Phase Cu₁₁In₉. Jedoch zerfällt letztere metallische Phase in Cu₁₆In₉ und flüssiges Indium bei einer Temperatur von ca. 310°C. Das flüssige Indium reagiert im Falle von Kupferarmut mit dem Schwefel und führt zu einem zusätzlichen Reaktionspfad über InS zu CuIn₅S₈. Unter Präparationsbedingungen mit Kupferüberschuss wird das Indium in einer intermetallischen Phase gebunden.<br><br>Erstmals konnte die Phase Digenite bei Temperaturen über 240°C beobachtet werden. Beim Abkühlen auf Raumtemperatur wandelt sich diese Phase unter dem Verbrauch von Schwefel in Covellite um.<br><br>Für Proben mit Kupferüberschuss konnte eine Wachstumskinetik proportional zur Temperatur beobachtet werden. Dieses Verhalten wurde durch eine stress-induzierte Diffusion als dominierenden Reaktionsmechanismus interpretiert. Dabei werden während der Bildung von CuInS<SUB>2</SUB> durch unterschiedliche Ausdehnungen der metallischen und sulfidischen Schichten eine Spannung in der CuInS<SUB>2</SUB>-Schicht induziert, die nach Überschreiten einer Grenzspannung zu Rissen in der CuInS₂-Schicht führt. Entlang dieser Risse findet ein schneller Transport der Metalle zur Oberfläche, wo diese mit dem Schwefel reagieren können, statt. Die Risse heilen durch die Bildung neuen Sulfids wieder aus. / In this work the reactive annealing of thin copper and indium films in elemental sulphur was investigated by energy dispersive X-ray diffraction. Measuring simultanously laser light diffusively reflected from the growth surface, a simple method for process monitoring could be established. The process monitoring using 635 nm laser light can now independently be used in production.<br><br>The growth of CuInS<SUB>2</SUB> from copper-indium precursors is dominated by transitions between intermetallic phases. CuInS<SUB>2</SUB> growths in the heat up period above 200 °C from the phase Cu<SUB>11</SUB>In<SUB>9</SUB>. However the latter metallic phase decomposes into Cu<SUB>16</SUB>In<SUB>9</SUB> and liquid indium at a temperature of 310 °C. The liquid indium reacts in the case of copper deficiency with sulphur to InS. This leads to an additional reaction path via InS to CuIn<SUB>5</SUB>S<SUB>8</SUB>. Under preparation conditions with copper excess to the contrary, indium is bound in an intermetallic phase.<br><br>For the first time the phase Digenite could be observed in a growth experiment at temperatures above 240 °C. During cool down to room temperature this phase transforms to Covellite by consumption of sulphur.<br><br>For samples with copper excess a growth kinetic proportional to the temperature was observed. This behaviour is interpreted by a stress induced reaction mechanism: During the formation of CuInS<SUB>2</SUB>, strain in the CuInS<SUB>2</SUB> thin film is induced due to different expansion coefficients of the metallic and sulphurous phases. After transgression of a certain strain limit, cracks within CuInS<SUB>2</SUB> are formed. Along these cracks, fast transport of metallic species to the surface can occur. There these species can react with the sulphur. The cracks can heal up by the formation of new sulphides.