Este trabalho objetivou caracterizar os danos pós-colheita em frutos de laranja &#39;Valência&#39; e de tangor &#39;Murcott&#39;, destinados à exportação, e em frutos de laranjas &#39;Pêra&#39;, &#39;Lima&#39; e &#39;Natal&#39; e de tangor &#39;Murcott&#39;, destinados ao mercado interno, após diferentes etapas do beneficiamento em packinghouse, em 2004 e 2005 e na Ceagesp-SP em 2006; identificar os pontos críticos e a magnitude de impacto em linhas de beneficiamento de citros dos packinghouses; e caracterizar a micoflora ambiental nos packinghouses e nos pontos de revenda de atacadistas da Ceagesp, assim como a micoflora da superfície de equipamentos e instalações e a presença de isolados de Penicillium spp. resistentes a fungicidas nos packinghouses. Frutos cítricos foram coletados na chegada ao packinghouse, após a pré-lavagem, após o desverdecimento, na banca, no palete e na Ceagesp, e armazenados durante 14 a 21 dias a 25&#176;C e 85-90% de UR. A incidência de injúrias foi avaliada visualmente a cada três dias. Para a avaliação da magnitude de impactos nos pontos de transferência da linha de beneficiamento empregou-se uma esfera instrumentada com registrador de aceleração (G). A micoflora ambiental foi amostrada mediante o método gravimétrico, com placas de Petri, contendo meio batata-dextrose-ágar, abertas por dois minutos. A micoflora de superfície de equipamentos e instalações foi amostrada mediante placas Rodac. Observou-se baixa incidência (<3,5%) de podridões nos frutos destinados à exportação. As principais podridões encontradas em laranja &#39;Valência&#39; e tangor &#39;Murcott&#39; foram a podridão peduncular de Lasiodiplodia e a antracnose, respectivamente. Nos frutos para o mercado interno a incidência de podridões atingiu valores médios entre 12,8% e 36,2%, ao final do armazenamento, sendo o bolor verde a principal doença pós-colheita nos diferentes frutos cítricos. As injúrias mecânicas de oleocelose foram crescentes com o beneficiamento até a banca de embalagem e a aplicação de cera reduziu a incidência de frutos murchos. Na avaliação dos impactos na linha de beneficiamento do packinghouse de exportação, 95% dos impactos variaram entre 30-95 G. Já no packinghouse de mercado interno, 94% dos impactos variaram entre 24-131 G. A população fúngica no ambiente e na superfície do packinghouse de exportação foi de 12,3 e 52,3 ufc/placa, respectivamente, enquanto a população fúngica no packinghouse de mercado interno foi de 46,3 e 68,2 ufc/placa, respectivamente. Posição intermediária aos packinghouses foi observada na Ceagesp, com uma população fúngica ambiental de 25,3 ufc/placa. Cladosporium e Penicillium foram os gêneros fúngicos mais abundantes. A contaminação de &#34;zonas limpas&#34; nos packinghouses (lavagem dos frutos, banca, caixa e contêiner) não foi substancialmente menor que nas &#34;zonas sujas&#34; (recepção dos frutos e primeira seleção). A porcentagem de isolados de P. digitatum resistentes a tiabendazol foi de 25,9 no ambiente e de 30,1 na superfície do packinghouse de exportação, enquanto que para imazalil foi de 1,5 no ambiente e de 16,0 na superfície. No packinghouse de mercado interno, a porcentagem de isolados de P. digitatum resistentes a tiabendazol foi de 51,9 no ambiente e de 39,2 na superfície, enquanto que para imazalil foi de 0,1 e 0,9, respectivamente. / The purposes of this work were a) to characterize postharvest injuries in &#39;Valência&#39; oranges and &#39;Murcott&#39; tangors aimed at the external market, and in &#39;Pêra&#39;, &#39;Lima&#39;, &#39;Natal&#39; oranges and &#39;Murcott&#39; tangors aimed at the internal market after different processing stages in a packinghouse in 2004 and 2005, and at Ceagesp-SP in 2006; b) to identify critical points and impact extent on processing lines in packinghouses; c) to characterize the environmental mycoflora in packinghouses and in retail points at Ceagesp; d) to characterize the superficial mycoflora of equipment and facilities, and e) to characterize the presence of isolated Penicillium spp. resistant to fungicides in packinghouses. Fruits were collected at the packinghouse, at their arrival, after pre-washing and degreening, from the packing table, from the pallet and at Ceagesp. They were stored for 14 to 21 days at 25&#176;C and 85-90% RH. The incidence of injuries was visually evaluated every three days. An instrumented sphere with acceleration register (G) was used to evaluate the extent of impacts at the transference points of the citrus processing line. The environmental mycoflora was sampled according to the gravimetric method, using Petri dishes containing potato-dextrose-agar medium opened for two minutes. The superficial mycoflora on equipment and facilities was sampled with Rodac plates. There was low rot incidence (under 3.5%) in fruits aimed at the external market. The main disease affecting &#39;Valência&#39; oranges and &#39;Murcott&#39; tangors were Lasiodiplodia stem-end rot and anthracnose, respectively. Rots averaged between 12.8% and 36.2% at the end of the storage period in fruits aimed at the internal market, and green mold was the main postharvest disease. Oleocellosis increased along the processing stages until the arrival of fruits at the packing table. Wax application reduced the incidence of wilted fruits. Ninety-five percent of the impacts in the packinghouse processing line in fruits aimed at the external market ranged between 30 and 95 G, while 94% of the impacts in fruits aimed at the internal market ranged between 24 and 131 G. The environmental and the packinghouse superficial fungal population in fruits aimed at the external market were 12.3 and 52.3 cfu/plate, respectively, while these populations in fruits aimed at the internal market were 46.3 and 68.2 cfu/plate, respectively. Intermediate values in relation to packinghouses were observed at Ceagesp, where the environmental fungal population was 25.3 cfu/plate. Cladosporium and Penicillium were the most prevailing genera of fungi. The contamination of &#34;clean zones&#34; in the packinghouses (washing of fruits, packing table, boxes and containers) was not substantially lower than contamination in &#34;dirty zones&#34; (reception of fruits and first selection). The percentage of P. digitatum isolates resistant to thiabendazole was 25.9 in the environment and 30.1 on the packinghouse surface for fruits aimed at the external market, while the corresponding data concerning isolates resistant to imazalil were 1.5 and 16.0, respectively. In the packinghouse of fruits aimed at the internal market, the percentage of isolates of P. digitatum resistant to thiabendazole was 51.9 in the environment and 39.2 on the packinghouse surface, while the corresponding data concerning isolates resistant to imazalil were 0.1 and 0.9, respectively.

<p>U radu je analiziran&nbsp; uticaj limunske kiseline na morfolo&scaron;ke, fiziolo&scaron;ke i&nbsp; biohemijske<br />karakteristike&nbsp; odabranih&nbsp; klonova&nbsp; vrba&nbsp; (Salix&nbsp; spp.)&nbsp; gajenih&nbsp; u&nbsp; zemlji&scaron;tu&nbsp; umereno zagađenom&nbsp; kadmijumom&nbsp; (Cd).&nbsp; Definisanjem&nbsp; parametara&nbsp; akumulacije,&nbsp; otpornosti&nbsp; i tolerantnosti različitih klonova vrba na prisustvo kadmijuma u podlozi, kao i uspe&scaron;nosti primene&nbsp; limunske&nbsp; kiseline&nbsp; kao&nbsp; helatora&nbsp; u&nbsp; procesu&nbsp; asistirane&nbsp; fitoremedijacije,&nbsp; mogao&nbsp; bi se&nbsp; identifikovati&nbsp; klon&nbsp; (ili&nbsp; klonovi)&nbsp; pogodan&nbsp; za&nbsp; dekontaminaciju&nbsp; zemlji&scaron;ta&nbsp; zagađenog kadmijumom. Da&nbsp; bi&nbsp; se&nbsp; postigao&nbsp; cilj&nbsp; istraživanja biljke su gajene u polu-kontrolisanim uslovima tokom 3 meseca. Eksperiment je podeljen u dve faze (dve godine istraživanja),zasnovane&nbsp; na&nbsp; razlikama&nbsp; u&nbsp; metodolo&scaron;kom&nbsp; pristupu.&nbsp; Tokom&nbsp; prve&nbsp; godine&nbsp; limunska kiselina je dodata jednom, dok je tokom druge druge godine aplikacija ovog helatora vr&scaron;ena&nbsp; u&nbsp; tri&nbsp; ponavljanja.&nbsp; U&nbsp; radu&nbsp; je&nbsp; analizaran&nbsp; sadržaj&nbsp; i&nbsp; distribucija&nbsp; Cd&nbsp; u&nbsp; zemlji&scaron;tu&nbsp; i<br />različitim&nbsp; biljnim&nbsp; organima&nbsp; (koren,&nbsp; izdanak,&nbsp; mladi&nbsp; i&nbsp; stari&nbsp; listovi);&nbsp; uticaj&nbsp; Cd i&nbsp; limunske kiseline na morfometrijske parametre: visina i prečnik izdanka, masa i povr&scaron;ina listova, broj&nbsp; listova,&nbsp; masa&nbsp; i&nbsp; zapremina&nbsp; korena;&nbsp; na&nbsp; fotosintetičke&nbsp; karakteristike:&nbsp; intenzitet fotosinteze,&nbsp; intenzitet&nbsp; transpiracije,&nbsp; stomatalnu&nbsp; provodljivost,&nbsp; intercelularnu koncentraciju&nbsp; CO2,&nbsp; efikasnost&nbsp; kori&scaron;ćenja&nbsp; vode,&nbsp; koncentraciju&nbsp; fotosintetičkih&nbsp; pigmenata; na mineralnu ishranu i distribuciju makronutrijenata u biljkama (sadržaj azota, fosfora i kalijuma);&nbsp; na&nbsp; sadržaj&nbsp; aminokiseline&nbsp; prolina&nbsp; i&nbsp; cisteina;&nbsp; na&nbsp; aktivnost&nbsp; antioksidativnih enzima&nbsp; (katalaza,&nbsp; askorbat-peroksidaza,&nbsp; gvajakol-peroksidaza),&nbsp; kao&nbsp; neezmiskih antioksidanata poput sadržaja redukovanog glutationa i tiola. Dobijeni&nbsp; rezultati&nbsp; su&nbsp; ukazali&nbsp; na&nbsp; genotipsku&nbsp; specifičnost&nbsp; analiziranih&nbsp; klonova&nbsp; vrba&nbsp; u procesu&nbsp; fitoremedijacije&nbsp; u&nbsp; zavisnosti&nbsp; od&nbsp; primenjenog&nbsp; tretmana,&nbsp; doze&nbsp; Cd&nbsp; i&nbsp; prisustva limunske kiseline. Toksično dejstvo nije bilo jasno uočljivo na morfolo&scaron;kom nivou, dok su&nbsp; primenjeni&nbsp; tretmani&nbsp; signifikantno&nbsp; uticali&nbsp; na&nbsp; fiziolo&scaron;ko-biohemijske&nbsp; procese&nbsp; u biljkama.&nbsp; Sa&nbsp; povećanjem&nbsp; sadržaja&nbsp; Cd&nbsp; u&nbsp; biljkama&nbsp; je&nbsp; utvrđena&nbsp; tendencija&nbsp; smanjenja intenziteta fotosinteze, transpiracije, kao i efikasnosti&nbsp; kor&scaron;ćenja vode, dok je primena limunske&nbsp; kiseline&nbsp; ublažila&nbsp; &scaron;tetan&nbsp; efekat&nbsp; ovog&nbsp; te&scaron;kog&nbsp; metala,&nbsp; &scaron;to&nbsp; je&nbsp; registrovano&nbsp; na<br />kombinovanim tretmanima.&nbsp; Kao odgovor na akumulaciju Cd u biljnom tkivu utvrđena<br />je&nbsp; promena&nbsp; aktivnosti&nbsp; antioksidativnih&nbsp; enzima,&nbsp; kao&nbsp; i&nbsp; neezimskih&nbsp; komponenti<br />odbrambenog&nbsp; sistema&nbsp; za&scaron;tite.&nbsp; Pored&nbsp; toga,&nbsp; u&nbsp; radu&nbsp; je&nbsp; utvrđeno&nbsp; da&nbsp; primena&nbsp; limunske kiseline&nbsp; utiče&nbsp; na&nbsp; usvajanje,&nbsp; akumulaciju&nbsp; i&nbsp; toleranciju vrba na prisustvo Cd,&nbsp; te&nbsp; rezultati ove&nbsp; studije&nbsp; imaju&nbsp; praktičan&nbsp; značaj&nbsp; u&nbsp; usavr&scaron;avanju&nbsp; tehnika&nbsp; fitoremedijacije&nbsp; i dekontaminacije zagađenih područja.</p> / <p>The role of citric acid on morphological, physiological and biochemical characteristics of selected willow clones (Salix spp.) grown in soil with moderately polluted cadmium (Cd)&nbsp; was&nbsp; presented.&nbsp; The&nbsp; aim&nbsp; of&nbsp; this&nbsp; study&nbsp; was&nbsp; to&nbsp; determine&nbsp; the&nbsp; Cd&nbsp; accumulation, translocation&nbsp; and tolerance of different willow clones, as well as the influence of citric acid as a chelator in the assisted phytoremediation process.&nbsp; In order to achieve this goal, plants&nbsp; were&nbsp; grown&nbsp; in&nbsp; semi-controlled&nbsp; conditions&nbsp; for&nbsp; 3&nbsp; months.&nbsp; The&nbsp; experiment&nbsp; was divided&nbsp; into&nbsp; two&nbsp; phases&nbsp; (two&nbsp; years&nbsp; of&nbsp; research),&nbsp; based&nbsp; on&nbsp; differences&nbsp; in&nbsp; the methodological approach, regarding the application of citric acid. During the first-year experiment, citric acid was added once, while in the second year the application of this chelator was performed in three repetitions.&nbsp; The analyses included:&nbsp; the accumulation and distribution of Cd in soil and various plant organs (root, stem, young and old leaves); influence of Cd and citric&nbsp; acid on morphometric parameters: stem hight and diameter, number&nbsp; of&nbsp; leaves,&nbsp; biomass&nbsp; and&nbsp; area&nbsp; of&nbsp; leaves,&nbsp; biomass&nbsp; and&nbsp; volume&nbsp; of&nbsp; the&nbsp; root;&nbsp; on&nbsp; photosynthetic&nbsp; characteristics:&nbsp; net&nbsp; photosynthetic&nbsp; and&nbsp; transpiration&nbsp; rate,&nbsp; water&nbsp; use efficiency, stomatal conductance, intercellular concentration of CO2, concentration of photosynthetic&nbsp; pigments;&nbsp; on&nbsp; mineral&nbsp; nutrition&nbsp; and&nbsp; distribution&nbsp; of&nbsp; macronutrients&nbsp; in plants (nitrogen, phosphorus and potassium content); on the content of the amino acid proline&nbsp; and&nbsp; cysteine;&nbsp; on&nbsp; the&nbsp; activity&nbsp; of&nbsp; antioxidant&nbsp; enzymes&nbsp; (catalase,&nbsp; ascorbate peroxidase,&nbsp; guaiacol&nbsp; peroxidase),&nbsp; as&nbsp; non- enzymatic&nbsp; components&nbsp; such&nbsp; as&nbsp; reduced glutathione and thiol content.<br />The obtained results indicated the genotypic specificity of the analyzed willow clones in the phytoremediation process, depending on the treatment applied, the Cd dose, and the presence of&nbsp; citric acid.&nbsp; The toxic effect was not evident on the morphological&nbsp; level, while&nbsp; the&nbsp; applied&nbsp; treatments&nbsp; showed&nbsp; a&nbsp; significant&nbsp; influence&nbsp; on&nbsp; the&nbsp; physiologicalbiochemical processes in the willows. The net photosynthetic rate, transpiration rate, as well as,&nbsp; water use eficiency&nbsp; showed decreasing with increasing Cd concentration in plant tissue,&nbsp; while&nbsp; the&nbsp; application&nbsp; of&nbsp; citric&nbsp; acid&nbsp; mitigated&nbsp; the&nbsp; harmful&nbsp; effect&nbsp; of&nbsp; this&nbsp; heavy metal, which was registered on combined treatments. In response to the accumulation of Cd in plant tissue, a&nbsp; change in the&nbsp; activity&nbsp; of&nbsp; anti-oxidant enzymes,&nbsp; as&nbsp; well as nonenzymatic&nbsp; components&nbsp; of&nbsp; the&nbsp; defense&nbsp; system&nbsp; has&nbsp; been&nbsp; established.&nbsp; In&nbsp; addition,&nbsp; the<br />application of citric acid showed the promotion role on the&nbsp; absorption, accumulation and tolerance of willows grown in moderately polluted soil cadmium, which has a practical significance in the improvement of phytoremediation techniques and decontamination of polluted soil.</p>

Com o objetivo de avaliar o efeito da cobertura morta, produzida pelos adubos verdes lab-lab (Dolichos lablab L.), guandu-anão (Cajanus cajan (L.) Millsp), crotálaria (Crotalaria juncea L.), guandu (Cajanus cajan (L.) Millsp), milheto (Pennisetum glaucum (L.) Leeke), uma mistura de três coberturas (D. lablab + C. cajan + C. juncea), e a infestação natural do pomar de laranja, composta principalmente por capim-colonião (Panicum maximum Jacq.), sobre as plantas daninhas, bem como avaliar o efeito destas coberturas sobre as seguintes plantas daninhas: poaia (Richardia brasiliensis Gomes.), capim-colonião, erva-palha (Blainvillea biaristata DC.), falsa-serralha (Emilia sonchifolia (L.) DC.), capim-colchão (Digitaria horizontalis (Retz.) Koel.), corda-de-viola (Ipomea grandifolia (Dammer.) O’Donell), picão-preto (Bidens pilosa L.), guanxuma (Sida santaremnensis H. Monteiro.) e tiririca (Cyperus rotundus (L.) Pers.), em condições de pós e pré-emergência, foram instalados dois experimentos em condições de campo e quatro em condições de casa de vegetação, na Escola Superior de Agricultura “Luiz de Queiroz”, Universidade de São Paulo, Departamento de Produção Vegetal, Piracicaba, S.P. O delineamento experimental foi de blocos casualizados para um experimento em campo e blocos casualizados no esquema fatorial para os demais. O manejo mecânico das diferentes vegetações, foi realizado mediante a utilização de roçadeira lateral, marca KAMAQ, modelo NINJA MAC 260 que esta desenhada para projetar o material verde cortado, sobre a projeção da copa da árvore cítrica, formando dessa maneira uma camada de cobertura morta. Os parâmetros avaliados durante a condução dos experimentos, foram os seguintes: avaliações de contagem da infestação de plantas daninhas por vaso e ou por m2 (densidade), determinações de algumas propriedades químicas do solo e avaliações de produção de biomassa das plantas daninhas. Pelos dados obtidos nas condições locais dos experimentos conduzidos pode-se observar que: a utilização de coberturas mortas produzidas pelas distintas vegetações contribui, significativamente, na redução das populações das plantas daninhas, sendo os melhores resultados obtidos com a vegetação natural e a mistura dos adubos verdes; e que a adubação em área total, independentemente da cobertura vegetal utilizada apresenta uma menor densidade de plantas daninhas nas linhas das plantas cítricas. Sendo assim pode se concluir que a utilização de adubos verdes pode contribuir de maneira significativa na redução da comunidade infestante, auxiliando de forma sustentável o manejo integrado de plantas daninhas; além de contribuir com outros benefícios inerentes a utilização dessa prática. / With the objective of evaluating the effect of the mulches produced by the cover crop Dolichos lablab, Cajanus cajan, Crotalaria juncea, Pennisetum glaucum, a mixture of three cover crops (Dolichos lablab + Cajanus cajan + Crotalaria juncea), and a natural infestation in orange tree plantations composed mostly by Panicum maximum on weeds and to evaluate the effect of these cover crop on the following weeds Richardia brasiliensis, Panicum maximum, Blainvillea biaristata, Emilia sonchifolia, Digitaria horizontalis, Ipomea grandifolia, Bidens pilosa, Sida santaremnensis and Cyperus rotundus, in conditions of pos and pre-emergence, two experiments in field conditions and four in greenhouse conditions were carried out at the Superior School of Agricultura "Luiz of Queiroz", University of São Paulo, Plant Production Department, São Paulo, Piracicaba – SP - Brazil. The experimental design used was of randomized blocks for an experiment in the field and randomized blocks in the factorial design for the others. The mechanical management of the different crops was carried out utilizing a KAMAQ lateral rotary mower Ninja Mac 260, designed to throw the cut crops down forming a layer of mulch around the citric plant. The data collected during the experiments were planta/m2 and plant/pot density, determination of some chemical conditions of the soil and weed dry biomass production in g/pot. In the carried out experiments, it could be observed that the use of mulches produced by different crops contributes significantly to reduce weeds. The best results were obtained in a natural infestation and the mixture of three cover crops. The fertilization in the whole area regardless the cover crops, presents a minor density of weeds in the lines of the citric plants. Furthermore, it can be concluded that the use of cover crops contributes widely to reduce weeds, supporting integrated management of weeds and providing with other inherent benefits.

Esse estudo tem como hipótese que a variação sazonal da fotossíntese de laranjeira ‘Valência’ está relacionada a fatores ambientais e endógenos. A menor atividade fotossintética durante os meses frios e secos está possivelmente associada à baixa temperatura e ao acúmulo de reservas, podendo ocorrer mesmo em condições de boa disponibilidade hídrica. A alta atividade fotossintética durante os meses quentes e chuvosos é possivelmente induzida pela maior disponibilidade de recursos naturais (água, energia solar e temperatura) e maior demanda por carboidratos, haja vista que nessa ocasião ocorre fluxo vegetativo intenso. O objetivo foi testar a hipótese acima, avaliando a variação anual de algumas características fisiológicas relacionadas à fotossíntese (trocas gasosas, fluorescência da clorofila, potencial de água no ramo e conteúdo foliar de carboidratos) de laranjeiras ‘Valência’ em condições de campo, em Cordeirópolis (SP). A influência da baixa disponibilidade hídrica sazonal foi verificada comparando-se plantas em condições naturais com plantas sob irrigação. A produção e algumas características biométricas foram avaliadas. A maior atividade fotossintética de laranjeiras ‘Valência’ ocorre durante a primavera, sendo induzida pelo aumento da temperatura e disponibilidade hídrica, enquanto que a menor fotossíntese ocorre durante o inverno, quando há baixa temperatura e deficiência hídrica. Durante o inverno, a menor fotossíntese não é associada ao conteúdo total de reservas foliares. Os valores máximos de assimilação de CO2 são observados na primavera, quando as condições ambientais são intermediárias entre o verão e o inverno e há fluxos vegetativo e reprodutivo nas laranjeiras. A alta demanda de carboidratos por esses drenos causa decréscimos no conteúdo de reservas foliares entre outubro e novembro, possivelmente estimulando a fotossíntese na primavera. Embora a fotossíntese das plantas no verão seja maior que no inverno, a atividade fotossintética não alcança valores próximos aos da primavera por limitações de origem bioquímica e estomática. A menor atividade bioquímica é induzida pela maior temperatura do ar em relação à primavera, em especial durante o período vespertino, enquanto que a limitação de origem estomática é causada pela alta demanda evaporativa do ar no verão. Durante o período quente e chuvoso, a atividade fotoquímica se ajusta às condições ambientais e não limita a fixação de carbono. A menor atividade fotossintética durante o inverno é ocasionada pela menor condutância estomática, devida à baixa temperatura do ar e solo. A ocorrência de deficiência hídrica no inverno causa redução do potencial de água nos ramos, diminuindo ainda mais a condutância estomática. No inverno, há limitação bioquímica da fotossíntese devida à baixa temperatura do ar, indicada pela redução da eficiência instantânea de carboxilação. Em relação ao metabolismo fotoquímico, não há indícios de limitação da fotossíntese. / This study has as hypothesis that the seasonal variation of photosynthesis in ‘Valencia’ sweet orange plant is related to environmental and endogenous factors. The lower photosynthetic activity during cold and dry months is possibly associated to low temperature and accumulation of leaf reserves, occurring even in well-watered plants.The higher photosynthetic activity during warm and rainy months is probably induced by higher availability of natural resources (water, sunlight and temperature) and by carbohydrate demand, since there is intense vegetative flush during this period. The objective was to test the above hyphotesis, evaluating the annual variation of some physiological characteristics related to photosynthesis (gas exchange, chlorophyll fluorescence, stem water potential and leaf carbohydrate content) of ‘Valencia’ sweet orange plants under field conditions, in Cordeirópolis (SP). The influence of low seasonal water availability was verified by comparing plants under natural with irrigated plants. Fruit production and some biometric characteristics were evaluated. The highest photosynthetic activity in ‘Valencia’ sweet orange plants occurred in spring, being induced by increase of temperature and water availability, while the lowest photosynthesis occurred in winter, when there is low temperature and water deficiency. During the winter, the lowest photosynthesis is not associated to the total reserve content in leaves. The maximum CO2 assimilation values are observed in spring, when environmental conditions are intermediate between summer and winter and there are vegetative and reproductive flushes in sweet orange plants. The high demand for carbohydrates in those sinks causes reduction in leaf reserve contents between october and november, probably estimulating the photosynthesis in spring. Although the photosynthesis in summer is higher than in winter, the photosynthetic activity does not reach values close to ones observed in spring due to biochemical and stomatal limitations. The low biochemical activity is induced by higher air temperature when compared to spring, mainly during afternoon, while the stomatal limitation is caused by the high air evaporative demand in summer. During the warm and wet period, the photochemical activity adjusts itself to environmental conditions and does not limit the carbon fixation. The low photosynthetic activity during winter is caused by low stomatal conductance as a consequence of low air and soil temperature. The occurrence of water deficiency in winter causes reduction of stem water potential, which is an additional factor leading to reduced stomatal conductance. In winter, there is biochemical limitation of photosynthesis due to low air temperature, as indicated by reduced instantaneous carboxylation efficiency. Regarding the photochemical metabolism, there are not signs of limitation to photosynthesis.

Realizaram-se estudos potenciostáticos e potenciodinâmicos do comportamento eletroquímico do estanho em meio ácido de perclorato de sódio desaerado, com adições sistemáticas de ácido cítrico. Paralelamente aos ensaios eletroquímicos acompanhou-se o estado superficial do eletrodo com microscópio de luz refletida e microscópio eletrônico de varredura (SEM). Foi constatada, inicialmente, a ocorrência da redução do perclorato em presença do eletrodo de estanho. A redução do perclorato de sódio 0,5 M no eletrodo de estanho ocorre durante catodizações em meio ácido, no intervalo de potenciais de -0,7 V a -1,3 V; sendo que a presença do óxido facilita a redução. A geração de CI- deve ocorrer após a redução do cloreto básico de estanho. A presença do ácido cítrico reduz, mas não inibe completamente, a formação de cloreto, e causa a formação de uma camada de óxido que contém átomos de estanho e cloro. O potencial crítico de corrosão foi determinado em meio de perclorato de sódio 0,5 M, no intervalo de pH de 1,0 a 4,0. Os resultados obtidos mostraram que o tipo de corrosão depende do pH. Em pH 3,0 e 4,0, a formação de pite é antecedida pela formação de uma camada de óxido, que pode ser descrita por um modelo de dissolução-precipitação. A nucleação e o crescimento dos pites envolvem uma série de contribuições de corrente: corrente de formação do óxido, corrente de nucleação instantânea e corrente de nucleação progressiva. A formação dos pites, em pH=4,0, ocorre em duas etapas: nucleação instantânea tridimensional seguida de crescimento controlado por difusão hemisférica (nucleação progressiva). A presença de cloreto agrava a corrosão do estanho com e sem a presença de ácido cítrico. A concentração mínima do ácido orgânico para inibir a corrosão por pite do estanho em CIO4- 0,5 M é de 10-2 M, para o intervalo de pH estudado. A influência de adições sistemáticas de ácido cítrico no perfil potenciodinâmico do estanho foi observada. A concentração mínima do ácido orgânico para modificar a curva I/E do estanho em CIO4- 0,5 M é de 10-2 M, para o intervalo de pH estudado. A presença do ácido orgânico causa a formação de óxidos mais estáveis que são detectados em dois picos de corrente. No primeiro ocorre a oxidação de espécies adsorvidas de acordo com o modelo de Srinivasan e Gileadi. No segundo, ocorre a oxidação de espécies em solução onde a formação do filme pode ser descrita pelo modelo de Muller e Calandra. / Potentiodynamic and potentiostatic studies of the electrochemical behaviour of tin in sodium perchlorate deaerated, with and without citric acid, were carried out. Besides the electrochemical experiments, the electrode surface was investigated by scanning electron microscopy (SEM) and by a metallographic microscope. The electrochemistry of tin in sodium perchlorate has been found unexpectediy to be complicated by the reduction of the perchlorate anion. The reduction process has been shown to take place through a potential region comprising the negative side of the double layer region and the positive side of the hydrogen region (-0,7 V &#8804; E &#8804; -1,3 V). The presence of oxide on the electrode surface favours the reduction. The reduction may occur in two steps: the formation of basic tin chloride followed by its reduction, producing CI-. The presence of citric acid reduces, but don\'t inhibits completely, the formation of chloride, during reduction, and induces the growth of an oxide layer which contains Sn and CI atoms. The breakdown potential was determined in sodium perchlorate 0,5 M in the pH range from 1,0 to 4,0. The results showed that the type of corrosion - pitting or general corrosion - depends on pH. At pH 3,0 and 4,0 the pit initiation is preceeded by the formation of an oxide layer, described by a dissolution-precipitation model for metal passivation. Pit nucleation and growth involve a number of contributions which were distinguished through the analysis of current transients at constant potentials. At pH 4,0, pit growth occurs in two steps and can, in principie, be described by instantaneous nucleation followed by progressive nucleation. The inhibiting effect of citric acid on pitting corrosion is recognized by the shift of the breakdown potentials to more positive values. The minimum concentration of the organic acid to inhibit pitting of tin is 10-2 M. The influence of systematic additions of citric acid on the potentiodynamic profile of tin in NaCIO4 0,5 M was observed. The minimun concentration of the organic acid to change the I/E curves is 10-2 M, in the pH range from 1,0 to 4,0. The scan rate dependence in the potential region of formation and reduction of the film showed that in a first stage adsorption occurs, according to Srinivasan and Gileadi\'s model. In the second stage, the v1/2 dependence found can be explained by ohmic resistance control, on the basis of Muller\'s passivation model.

In the last decades, intensive research has been carried out in order to replace oil-based polymers with bio-based polymers due to growing environmental concerns. So far, most of the barrier materials used in food packaging are petroleum-based materials. The purpose of the barrier is to protect the packaged food from oxygen, water vapour, water and fat. The mechanical and barrier properties of coatings based on starch-plasticizer and starch-poly(vinyl alcohol) (PVOH)-plasticizer blends have been studied in the work described in this thesis. The plasticizers used were glycerol, polyethylene glycol and citric acid. In a second step, polyethylene coatings were extruded onto paperboard pre-coated with a starch-PVOH-plasticizer blend. The addition of PVOH to the starch increased the flexibility of the film. Curing of the film led to a decrease in flexibility and an increase in tensile strength. The flexibility of the starch-PVOH films was increased more when glycerol or polyethylene glycol was added than citric acid. The storage modulus of the starch-PVOH films containing citric acid increased substantially at high temperature. It was seen that the addition of polyethylene glycol or citric acid to the starch-PVOH blend resulted in an enrichment of PVOH at the surface of the films. Tensile tests on the films indicated that citric acid acted as a compatibilizer and increased the compatibility of the starch and PVOH in the blend. The addition of citric acid to the coating recipe substantially decreased the water vapour transmission rate through the starch-PVOH coated paperboard, which indicated that citric acid acts as a cross-linker for starch and/or PVOH. The starch-PVOH coatings containing citric acid showed oxygen-barrier properties similar to those of pure PVOH or of a starch-PVOH blend without plasticizer when four coating layers were applied on a paperboard. The oxygen-barrier properties of coatings based on a starch-PVOH blend containing citric acid indicated a cross-linking and increase in compatibility of the starch-PVOH blends. Polyethylene extrusion coating on a pre-coated paperboard resulted in a clear reduction in the oxygen transmission rate for all the pre-coating formulations containing plasticizers. The addition of a plasticizer to the pre-coating reduced the adhesion of polyethylene to pre-coated board. Polyethylene extrusion coating gave a board with a lower oxygen transmission rate when the paperboard was pre-coated with a polyethylene-glycol-containing formulation than with a citric-acid-containing formulation. The addition of polyethylene glycol to pre-coatings indicated an increase in wetting of the pre-coated paperboard by the polyethylene melt, and this may have sealed the small defects in the pre-coating leading to low oxygen transmission rate. The increase in brittleness of starch-PVOH films containing citric acid at a high temperature seemed to have a dominating effect on the barrier properties developed by the extrusion coating process. / Over the last few decades, industry and academia have made joint efforts to generate knowledge about renewable barrier materials in order to replace the oil-based barrier materials currently used in food packaging. This work has focused on the possibility of producing a material with high oxygen barrier properties including polyethylene as a moisture protection. The flexibility of starch films was increased by adding poly(vinyl alcohol) (PVOH) to the starch and the addition of a plasticizer to the starch-PVOH blend films further increase the flexibility of the films. The plasticizers used were glycerol, polyethylene glycol and citric acid. Curing of the films reduce their flexibility. The addition of citric acid to a starch-PVOH blend increased the compatibility of the starch-PVOH blend and affected the barrier properties of the coating layers containing citric acid. When a sufficient number of coating layers was applied, the starch-PVOH-citric-acid coatings showed oxygen-transmission-rate-values similar to those of the pure PVOH and of the starch-PVOH blend without plasticizers. Polyethylene extrusion coating on pre-coated paperboard resulted in a clear reduction in the oxygen transmission rate of all the pre-coating recipes based on starch-PVOH blends. The polyethylene extrusion coating showed a higher oxygen transmission rate for a board pre-coated with citric-acid-containing recipes than for a board pre-coated with polyethylene-glycol-containing recipes.

Lanthanum orthoborate (LaBO3) has aroused interest of scientists for many decades because of their remarkable properties and potential applications. They provide favorable magnetic properties for various applications. Additionally, they possess high VUV transparency and exceptional optical damage when they compose with rare earth elements. This study comprises the synthesis of pure lanthanum orthoborate, europium, dysprosium and terbium doped lanthanum orthoborate by two methods with v three fuels, citric acid, glycine and urea. LaBO3 has already been synthesized by various methods, however / in this work, two alternative roads are suggested, microwave assisted method and sol-gel microwave assisted method. The second task of the work is to find out the best luminescent product by altering the synthesis conditions, type of the doping material and the doping amount of the rare earth element. For the microwave assisted combustion method, urea was used as a fuel. After synthesis in the microwave oven, further heating up to 950&deg / C was performed. For the microwave assisted sol-gel method, citric acid and glycine were used. After obtaining the gel mixture, the product is synthesized in the microwave oven at 1200 W for ten minutes. For this route, again 950&deg / C heating for 2 hours was performed. Powder X-ray diffraction method was employed for the characterization of the material. The morphological properties of doped and un-doped materials were studied by SEM (Scanning Electron Microscope) and TEM (Transmission Electron Microscope). Besides, FT-IR (Fourier Transform Infra red) spectrometry analyses were performed to detect the differences in the bond structure and also to identify the corresponding bands. Luminescence studies were performed to detect the best emission intensities by using Fluorescence spectroscopy. The XRD patterns confirmed that lanthanum orthoborate production was successful by three precursors. The space group is Pnma, and the crystal system is orthorhombic with the unit cell dimensions / a= 5.8761(1)

The present study assessed and compared the influence of the root canal treatment with and without passive ultrasonic irrigation with 17% ethylenediaminetetraacetic acid (EDTA) and 10% citric acid on the sealing of pre-molars root canal fillings. A hundred and fifteen single-rooted, human mandibular pre-molars, with oval canal, were selected. The teeth were prepared with rotatory instrumentation and irrigated according to the following protocols (n=23): G1, 17% EDTA + US; G2, 17% EDTA; G3, 10% citric acid + US; G4, 10% citric acid and a control group, 2,5%.sodium hypochlorite (NaOCl). The specimens were filled according to the no compaction technique and then inserted to a device for measuring the glucose leakage. Leakage was assessed through a Glucose Kit in a spectrophotometer at 7 and 30 days. Kruskal-Wallis test results showed less leakage on passive ultrasonic irrigation groups, with both test solutions (p<0,05). Mann-Whitney analysis showed that teeth treated with 17% EDTA showed less leakage levels then the ones treated with 10% citric acid (p<0,05). Passive ultrasonic irrigation with chelating solutions, specially EDTA, results in a better sealing of root canal filling Key-words: passive ultrasonic irrigation; sealing; root canal filling; citric acid. / O objetivo desse estudo foi avaliar comparativamente a influência do tratamento do canal radicular com e sem irrigação ultrassônica passiva com ácido etilenodiaminotetracético 17% (EDTA) e ácido cítrico 10% sobre o selamento da obturação de canais radiculares de pré-molares. Foram utilizados cento e quinze pré-molares inferiores humanos de canal único e oval. Os elementos foram preparados com instrumentação rotatória e irrigados segundo os seguintes protocolos (n=23): G1, EDTA 17% + US; G2, EDTA 17%; G3, ácido cítrico 10% + US; G4, ácido cítrico 10% e um grupo controle, hipoclorito de sódio (NaOCl) 2,5%. Todos os elementos foram obturados segundo a técnica da não compactação e em seguida inseridos em um dispositivo de infiltração de glicose. As medidas de infiltração foram analisadas através de um Kit Glicose em espectrofotômetro nos intervalos de tempo de 7 e 30 dias. Os resultados do teste de Kruskall-Wallis mostraram haver menor infiltração nos grupos nos quais foi utilizada a irrigação ultrassônica, com ambas as soluções teste (p<0,05). Segundo a análise de Mann-Whitney, o tratamento com EDTA 17% proporcionou menores níveis de infiltração comparado ao ácido cítrico 10% (p<0,05). A ativação ultrassônica de soluções quelantes durante o preparo, especialmente com o EDTA, melhora o selamento da obturação do canal radicular.

Made available in DSpace on 2016-06-02T19:51:26Z (GMT). No. of bitstreams: 1 DissLAS.pdf: 1610456 bytes, checksum: 384963044acc35e1a9c43651ac50d949 (MD5) Previous issue date: 2006-12-18 / In the last decade there has been a growth on society concern with topics related to epics, citizenship, human rights, economic development and social belonging. In this sense, all kinds of organizations are more and more worried on reaching and showing performance related to environment protection, socially and economically correct, controlling the impacts of its relations, processes, products and services in society according to its politics and its social responsibility goals. However, many doubts concerning what really is socially responsible in practical application, therefore in its speech. Although there has been indicators that point to the industries mentality and posture change related to its engagement in the social space. The reasons which promoted it are still doubtful. Probably this reasons must achieve specific shaping in specific realities as well, so the importance of the study: a contributions on the comprehension as how the industrial social responsibility is configured in the Sao Paulo´s orange-juice complex. Thus, the objective of this work is to design a framework of industrial social responsibility in the citric section of the São Paulo State and therefore there has been developed a case study of three different important agents in this reproductive chain. Throughout this study there is a search to build up an analysis in the comprehension of this issues on what concerns to be socially responsible, approaching and existent dynamic in the sector environmental institution that reinforces the adoption and the restructuring of acts related to industrial social responsibility. As a result it has been notice that the socially responsible acts are acts which has been an adaptation from pressure received by each agent, as well as they are isomorphic within each segment since it can be verified the existence of realities, power and legitimacy very different among the agents. It has also been noticed that the activities has been well accepted by human resources professionals and that the industrial social responsibility has been taken as a management tool. / Nas últimas décadas tem crescido a mobilização e a preocupação da sociedade com temas associados à ética, cidadania, direitos humanos, desenvolvimento econômico e sustentável e inclusão social. Neste sentido, organizações de todos os tipos estão cada vez mais preocupadas em atingir e demonstrar desempenhos ambientais, econômicos e sociais adequados, controlando os impactos de suas relações, processos, produtos e serviços na sociedade, de forma consistente com sua política e com seus objetivos de responsabilidade social. No entanto, muitas dúvidas persistem a respeito do que seja ser socialmente responsável na prática, assim como no discurso. Apesar de já existirem, de modo geral, indicadores que sinalizam para a mudança de mentalidade e posturas das empresas quanto ao seu engajamento no espaço social, as razões que provocaram tal engajamento ainda geram dúvidas. Provavelmente, tais razões devem ganhar contornos específicos em realidades também especificas, o que acaba por exigir estudos em diferentes ambientes. Daí a importância desse estudo: a contribuição para compreender como a responsabilidade social empresarial se configura no setor citrícola paulista. Assim, o objetivo deste trabalhado é desenhar um arcabouço de responsabilidade social empresarial no setor citrícola do Estado de São Paulo e para tanto, realizou-se um estudo de caso com três diferentes atores importantes desta cadeia produtiva. Com este estudo buscou-se construir uma análise do entendimento destes, no tocante a ser socialmente responsável, abordando a dinâmica existente no ambiente institucional do setor, que reforça a adoção e estruturação de ações relativas a responsabilidade social empresarial. Como resultado percebeu-se que as ações de responsabilidade social são ações adaptativas às pressões sofridas por cada ator, bem como são isomórficas dentro de cada segmento pois, no caso do setor em estudo, pode-se verificar a existência de realidades, poder e legitimidade bem diferente entre os atores. Constatou-se, também, que as atividades foram abraçadas pelos profissionais de recursos humanos e que a responsabilidade social empresarial passou a ser vista como uma ferramenta de gestão.

Made available in DSpace on 2014-10-09T12:44:53Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:59:46Z (GMT). No. of bitstreams: 1 07160.pdf: 4424646 bytes, checksum: 4938889fd9a885e62dfeaafc99b1274d (MD5) / Dissertacao (Mestrado Profissionalizante em Lasers em Odontologia) / IPEN/D-MPLO / Instituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN-SP; Faculdade de Odontologia, Universidade de Sao Paulo