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Simazine and dalapon have been used to control weeds in many crops during the last few years, but in 1963, when this study was begun, their uses in fruit orchards were limited. To study the effects of simazine and dalapon both on the control of weeds and on various metabolic changes in apple (Malis pumila), Montmorency sour cherry (Prunus cerasus), sweet cherry (Prunus avium), and Prunus mahaleb root s tock, experiment s were conducted from 1964 through 1966 in both the field and in the greenhouse. The application of a low do sage of simazine (4 lb/A) to soil around twelve-year-old Montmorency sour cherry trees in the field resulted in 60 to 70 percent weed control, while tree growth, chlorophyll content of the leaves, fruit y i e ld, and fruit quality were enhanced. Simazine applied at the higher dosages (8 and 12 lb/A) gave very good weed control (up to 100 percent) but reduced tree growth, chlorophyll content, and fruit yield and quality. In the greenhouse , the application of simazine at all three levels caused severe damage to R· mahal eb and sweet cherry trees and hence reduced the water uptake , but young apple trees treated with simazine showed no visible damage , although water uptake was reduced. In young sour cherry trees treated with 4 lb/A simazine, slight chlorophyll increase s we re observed , while at the higher dosages , decreases were observed. Simazine applied to the soil surface was absorbed readily by all trees. It accumulated in large amounts in the l eaves compared with the other parts of these plants. Sour cherry trees accumulated more simazine than apple trees. Results from both field and greenhouse trial sindicate that apple trees were comparatively resistant, and sweet cherry and ~ · mahaleb trees were very sensitive. Enzyme analys i s indicated that simazine caused an increase in the activity of peroxidase and polyphenol oxidase in all trees. The activity of catalase and cytochrome oxidase was decreased in f. mahaleb, sweet cherry , and sour cherry trees, but apple trees showed an increase in both catalase and cytochrome oxidase activity. Compared to the other trees , the most tolerant , untreated trees (apple) had relatively high peroxidase and low polyphenol oxidase activity, with moderate catalase and cytochrome oxidase activity . The moderately resistant species ( sour cherry) had moderate peroxidase, catalase, and cytochrome oxidase activity but very low polyphenol oxidase activity , while the sensitive trees (~ . mahaleb and sweet cherry) showed a wide range of enzyme activities . ~ · mahaleb leaves had low peroxidase and catalase activities and high polyphenol oxidase and cytochrome oxidase activities, but sweet cherry leaves had moderate peroxidase and polyphenol oxidase , high catalase, and l ow cytochrome oxidase activities. The movement of simazine in the soil was s low. Regardless of applied amounts, most of the herbicide stayed in the top 0-6 inches of soil after surface application, but movement in t he soil increased as the rate of application increased. The post-emergence application of dalapon to a Montmorency sour cherry orchard reduced weed growth in general, but complete weed control was not observed. Tree growth, chlorophyll content of the l eaves, fruit yield, and fruit quality of dalapon-treated Montmorency sour cherry trees were reduced compared with the untreated control. These reductions became greater as t he dalapon dosage increased .

The herbicide simazine (2-chloro-4,6-bis(ethylamino)- 1,3,5-triazine) was found to have an inhibitory effect on nitrification in pure and mixed cultures of the nitrifying bacteria. Simazine concentrations of 6 and 9ppm inhibited the rate of nitrification in soil perfusion units, and an abnormally high level of nitrite nitrogen was observed in the herbicide treatments. The herbicide had no effect on the growth of Nitrosomonas europaea in shake flask culture, but did inhibit the growth of Nitrobacter agilis. The addition of yeast extract to the culture medium did not reverse the inhibition. Simazine did not inhibit the respiration of N. agilis even at a 100ppm concentration. Five organisms were isolated which could utilize simazine as a sole source of carbon and nitrogen. Pure cultures of these organisms were made and several were identified. / Master of Science

Made available in DSpace on 2016-08-10T10:44:58Z (GMT). No. of bitstreams: 1 ADIBE GEORGES KHOURI.pdf: 2436504 bytes, checksum: 933a9665e66c9bc05685510602f426a8 (MD5) Previous issue date: 2007-01-31 / A cultura do abacaxi sempre se destacou na fruticultura, graças não só às qualidades deste fruto, bastante apreciado em todo mundo, mas principalmente pela rentabilidade da cultura, responsável por sua grande demanda e importância econômica. A necessidade e a ambição de se ter uma produção cada vez maior e melhor fazem com que haja o emprego, por vezes de forma errônea ou irresponsável, de determinados pesticidas, esperando assim, realizar de forma satisfatória a defesa da matéria de origem agrícola, e provocando algumas reações adversas ao consumidor desse produto. Entre os malefícios mais comumente detectáveis existem os diversos processos de manifestações alérgicas e em longo prazo, o desenvolvimento de alguns tipos de câncer. Neste ensaio preocupou-se em identificar a atrazina e simazina, agrotóxicos utilizados na agricultura do abacaxi. Foi realizado o estudo a partir da aplicação de técnicas mais modernas como: extração por solvente, extração em fase sólida (SPE) e cromatografia gasosa de alta resolução (HRGC). Observou-se que amostras consideradas do grupo orgânico apresentaram picos aproximados dos picos de retenção dos pesticidas atrazina e simazina. Os abacaxis comprados em supermercados não apresentaram nenhum resíduo desses pesticidas, o que pode indicar que as exigências de controle de qualidade nestas empresas estão sendo seguidos com mais rigor, enquanto nos abacaxis ditos como orgânicos, parece faltar inspeção por grupos competentes.

Ces travaux voulaient démontrer que l'hydrolyse d'herbicides dans le sol, l'hiver comme l'été, est catalysée par l'acidité de surface des minéraux argileux. Le manque d'eau pouvant limiter la réaction, l'hydrolyse a d'abord été étudiée dans l'eau. La demi-vie d'hydrolyse acide du diuron dans l'eau a été estimée à 320 et 5,2 ans, à 0 et 22 °C respectivement, entre pH 1 et -1 où la vitesse de la réaction plafonne. Par contre en 16 semaines, la quantité initiale d'atrazine ou de simazine dans l'eau est réduite de 20 % à pH 2,0 à 0 °C, et 3,3 à 22 °C. Une nouvelle équation, basée sur la fonction acide Ho plutôt que le pH, impliquant les triazines neutre, mono-, di- et triprotonées, a été proposée pour prédire la demi-vie en solutions très acides. Deux pellicules plastiques, l'une en polyethylene basse densité (LDPE), l'autre en chlorure de polyvinyle (PVC) plastifié, ont été testées comme support transparent dans l'UV-Visible de films minces d'argile imprégnés d'herbicide. Le LDPE absorbe moins dans cette région spectrale. Sa faible polarité entraîne toutefois de sérieux problèmes d'étalement et d'adhésion de l'argile. Le PVC libère du HCl(g), mais en quantité négligeable et limitée à 21 °C. L'hydrolyse acide de l'atrazine et du diuron à la surface de films d'argile supportés par la pellicule de PVC, a été étudiée à -4 et 21 °C, par spectroscopie UV-Visible de transmission. Les formes -K, -Ca, -Mg, -Zn, -Fe, -Al et -H de deux smectites et d'une vermiculite ont été préparées. Les argiles homoioniques déshydratées à l'air libre n'ont montré aucune activité catalytique vis-à-vis des herbicides en 16 semaines, à l'exception de la montmorillonite-H où l'atrazine est protonée au-dedans de 24 heures. Cette réactivité s'explique seulement par l'accessibilité de l'atrazine neutre à l'espace interfoliaire de la montmorillonite-H, et l'acidité de surface particulièrement élevée de celle-ci. L'atrazine n'est pas hydrolysée sur la montmorillonite-H en raison de l'insuffisance d'eau disponible. L'absence de protonation de l'atrazine sur les autres argiles, lorsque l'ouverture des feuillets permet son accès, découle de leur trop forte teneur en eau résiduelle. Le diuron ne pénètre pas dans l'espace interfoliaire des argiles.

Made available in DSpace on 2016-08-10T10:45:28Z (GMT). No. of bitstreams: 1 MARCIA HELEN DIAS DA MOTA.pdf: 3096457 bytes, checksum: 373749bd3d6a0daeadeb7605ced335a9 (MD5) Previous issue date: 2007-01-31 / In this work, were analyzed samples of apples purchased at several locations in the city of Goiânia, Goiás, in order to verify that they are contaminated with residues of the herbicides atrazine and simazine, widely used in the brazilian agriculture. For this, tests were made with a certified samples grown without addition of these products (white) and compared the results with tests performed on real samples of the fruit consumed by the general population. The sample was macerated and homogenized with C18, placed in a column with silica gel and eluted again with 10 ml of acetone. Then it was evaporated and eluded again in 1.0 ml of acetone, in order to be applied in the chromatograph. The technique used was gaseous chromatography, whose methodology is widely known by the scientific community, and was chosen by both the precision as the availability of the equipment. The development of this work is an attempt to provide further foundation for the struggle for development of sustainable agriculture, which carries a negative influence on less than current practice. / Neste trabalho, foram feitas análises de amostras de maçãs, adquiridas em diversas localidades da cidade de Goiânia, Goiás, com o intuito de verificar se as mesmas estão contaminadas com resíduos dos herbicidas atrazina e simazina, amplamente utilizados na agricultura brasileira. Para isso, foram feitos testes com amostras certificadamente cultivadas sem adição desses produtos (branco) e comparados os resultados com os testes efetuados nas amostras reais, do fruto consumido pela população em geral. A amostra foi macerada e homogeneizada com C18, colocada em uma coluna com sílica gel e eluída com 10 mL de acetona. Em seguida, o filtrado foi evaporado e rediluído em 1,0 mL de acetona, a fim de ser aplicado no cromatógrafo. A técnica utilizada foi a da cromatografia gasosa, cuja metodologia é de amplo conhecimento da comunidade científica, e foi escolhida tanto pela precisão quanto pela disponibilidade de aparelhagem. O desenvolvimento deste trabalho é uma tentativa de fornecer mais alicerces para a luta pelo desenvolvimento de uma agricultura sustentável, que exerça uma influência negativa relativamente menor que as atuais práticas.