As the importance of cotton (Gossypium hirsutum L.) to Virginia crop growers has increased, so has the need for more efficient weed control programs. Current cotton herbicides do not control all broadleaf weeds over the entire growing season, and many cotton herbicides must be applied at specific growth stages in order to reduce crop injury. CGA 362622 is an experimental sulfonylurea herbicide that controls many broadleaf weeds at low use rates. Field, greenhouse, and laboratory studies were conducted to evaluate the potential benefit of CGA 362622 to Virginia cotton growers. Postemergence applications of CGA 362622 resulted in moderate crop response that proved transient in all instances and did not affect cotton yield. Broadleaf weed control from herbicide combinations with CGA 362622 generally controlled weeds more consistently than individual herbicide applications. Timely applications of CGA 362622 controlled common ragweed (Ambrosia artemisiifolia L.), common lambsquarters (Chenopodium album L.), annual morningglory species (Ipomoea spp.), and common cocklebur (Xanthium strumarium L.). However, CGA 362622 applications generally did not control spurred anoda (Anoda cristata (L.) Schlecht.), jimsonweed (Datura stramonium L.), velvetleaf (Abutilon theophrasti Medicus), or annual grass species, but combination treatments of CGA 362622 plus pyrithiobac did control velvetleaf, spurred anoda, and jimsonweed. Combinations of CGA 362622 plus glyphosate controlled common lambsquarters and smooth pigweed (Amaranthus hybridus L.) better than glyphosate alone, and in most instances controlled annual morningglory species better than glyphosate applied alone. Timely applications of CGA 362622 plus bromoxynil controlled velvetleaf, smooth pigweed, common ragweed, common lambsquarters, and common cocklebur. Spurred anoda control was generally not acceptable from CGA 362622, bromoxynil, or CGA 362622 and bromoxynil combinations. In laboratory studies, results supported differential absorption, translocation, and metabolism as the main factors for differential tolerance of cotton, spurred anoda, and smooth pigweed to CGA 362622. Rapid translocation and a slow rate of metabolism likely explains the susceptibility of smooth pigweed to this herbicide, while reduced absorption and translocation plus rapid metabolism contribute to CGA 362622 tolerance in cotton. Limited translocation may also explain the intermediate tolerance of spurred anoda to the herbicide CGA 362622. / Ph. D.

Secretion of appropriate amounts of insulin from pancreatic β-cells is crucial for glucose homeostasis. The β-cells release insulin in response to glucose and other nutrients, hormones and neurotransmitters, which trigger intracellular signaling cascades, that result in exocytotic fusion of insulin-containing vesicles with the plasma membrane. Increases of the intracellular concentration of calcium ions ([Ca2+]i) trigger exocytosis, whereas the messenger cyclic adenosine monophosphate (cAMP) amplifies various steps of the secretion process. The protein Epac2 mediates some effects of cAMP, but little is known about its regulation in β-cells. In this study, the spatio-temporal dynamics of Epac2 was investigated in insulin-secreting MIN6-cells and primary β-cells using various cell signaling biosensors and live-cell fluorescence microscopy approaches. Increases in the cAMP concentration triggered translocation of Epac2 from the cytoplasm to the plasma membrane. Oscillations of cAMP induced by glucose and the insulin-releasing hormone GLP-1 were associated with cyclic translocation of Epac2. Analyses of Epac2 mutants showed that the high-affinity cyclic nucleotide-binding domain and Ras-association domains were crucial for the translocation, whereas neither the DEP domain, nor the low-affinity cAMP-binding domain were required for membrane binding. However, the latter domain targeted Epac2 to insulin granules at the plasma membrane, which promoted their priming for exocytosis. Depolarization-induced elevations of [Ca2+]i also stimulated Epac2 translocation, but the effects were complex and in the presence of high cAMP concentrations, [Ca2+]i increases often reduced membrane binding. The stimulatory effect of Ca2+ was mediated by increased Ras activity, while the inhibitory effect reflected reduced concentrations of the membrane phospholipid PtdIns(4,5)P2. Anti-diabetic drugs of the sulfonylurea class, suggested to directly activate Epac2, induced translocation indirectly by depolarizing β-cells to increase [Ca2+]i. Epac2 is an activator of Rap GTPases, and its translocation increased Rap activity at the plasma membrane. It is concluded that the subcellular localization of Epac2 is controlled by a complex interplay between cAMP, Ca2+ and PtdIns(4,5)P2 and that the protein controls insulin release by binding to the exocytosis machinery. These results provide new insights into the regulation of β-cell function and may facilitate the development of new anti-diabetic drugs that amplify insulin secretion.

No limiar do ano de 2012 a população humana chegou a 7 bilhões de pessoas. Há apenas 12 anos atrás, 6 bilhões de seres humanos habitavam nosso planeta. O crescente e acentuado aumento da população tem exigido um uso exacerbado de bens naturais, principalmente do recurso solo, principal via para produção de alimentos. Para aumentar a produção de alimentos, sem aumentar a área cultivada, frequentemente faz-se o uso de pesticidas. Hoje, os herbicidas são os pesticidas mais comercializados, correspondendo à metade do mercado. Dentre seus grupos químicos mais comuns, há um destaque para as sulfonilureias, segunda classe de herbicida mais consumida em todo o mundo, contudo pouco investigada no âmbito da química analítica e ambiental. Uma vez no ambiente, o princípio ativo das sulfonilureias pode se tornar um risco para todo o ecossistema. Nos sedimentos, a sorção dos herbicidas determina quanto destes ficarão retidos na matriz e quanto estará disponível na solução do solo, contaminando os recursos hídricos. Neste sentido, o presente trabalho teve como objetivo realizar estudos que visam a determinar a dinâmica do herbicida etilclorimuron (exemplar da família das sulfonilureias) no ambiente. Estes estudos foram realizados via cinética e isotermas de adsorção em sedimentos. Compararam-se sedimentos com diferentes características em função do uso dado à terra (amostras Zona Agrícola, Zona Pecuária e Estação Ecológica). Para as três amostras, o modelo cinético obtido foi de pseudo-segunda-ordem. A amostra Zona Pecuária foi a que apresentou maior retenção (37,97.102 ug kg-1), logo uma dinâmica mais lenta. As demais amostras não apresentaram diferenças significativas para o processo sortivo (retenção de 29,07.102 e 31,67.102 ug kg-1 para as amostras Zona Agrícola e Estação Ecológica). Todos os sedimentos adsorveram de acordo com o modelo de Freundlich e suas isotermas foram classificadas como sendo do tipo C. A adsorção ocorreu com a formação de multicamadas e interações de natureza física (fisiossorção). O herbicida foi determinado via HPLC-UV. O método analítico foi validado de acordo com os documentos do INMETRO e da ANVISA e quando cabível de valores orientativos, os resultados obtidos se encontram em concordância. / On the threshold of 2012 the human population reached 7 billion of people. Only 12 years ago, 6 billion of human beings inhabited our planet. The growing and accentuated increase of the population has required an overuse of natural resources, especially the soil, main via for food production. Intending to increase the food production, without increasing the area under cultivation, pesticides are often used as an alternative. Nowadays herbicides are the pesticides most commonly traded, corresponding to a half of its market. Among the most common chemical groups, sulphonylureas have a noteworthy, the second most used class of herbicides throughout the world, however little studied in the context of analytical and environment chemistry. Once in the environment, the active principles of sulphonylureas may become a risk to the entire ecosystem. The sorption of herbicides in sediments determines how these will be retained in the matrix and how much will be available in soil solution, contaminating water resources. In this sense, this study aimed to realize studies for determinate the dynamics of chlorimuron ethyl (example of sulphonylurea herbicide family) in the environment. These studies were performed via kinetic and isotherm of absorptions in sediments. Sediments were compared with different characteristics depending of the use of earth (samples: Agricultural Zone, Farming Zone and Ecological Station). For all three samples, the obtained kinetic model was pseudo-second order. The farming Zone showed highest retention (37.97x102 ug kg-1), therefore a slower dynamic. The remaining samples didn\'t showed significant differences for the sorption process (retention of 29.07x102 and 31.67x102 ug kg-1 for Agricultural Zones and Ecological Stations). All sediments adsorbed according to Freundich\'s model and their isotherms were classified as C type. Adsorption occurred with the formation of multilayer and interactions were of physical type (physisorption). The herbicide was determined by HPLC-UV. The analytical method was validated in according with the INMETRO and ANVISA documents and, when appropriated of references values, the results have been in agreement.

No limiar do ano de 2012 a população humana chegou a 7 bilhões de pessoas. Há apenas 12 anos atrás, 6 bilhões de seres humanos habitavam nosso planeta. O crescente e acentuado aumento da população tem exigido um uso exacerbado de bens naturais, principalmente do recurso solo, principal via para produção de alimentos. Para aumentar a produção de alimentos, sem aumentar a área cultivada, frequentemente faz-se o uso de pesticidas. Hoje, os herbicidas são os pesticidas mais comercializados, correspondendo à metade do mercado. Dentre seus grupos químicos mais comuns, há um destaque para as sulfonilureias, segunda classe de herbicida mais consumida em todo o mundo, contudo pouco investigada no âmbito da química analítica e ambiental. Uma vez no ambiente, o princípio ativo das sulfonilureias pode se tornar um risco para todo o ecossistema. Nos sedimentos, a sorção dos herbicidas determina quanto destes ficarão retidos na matriz e quanto estará disponível na solução do solo, contaminando os recursos hídricos. Neste sentido, o presente trabalho teve como objetivo realizar estudos que visam a determinar a dinâmica do herbicida etilclorimuron (exemplar da família das sulfonilureias) no ambiente. Estes estudos foram realizados via cinética e isotermas de adsorção em sedimentos. Compararam-se sedimentos com diferentes características em função do uso dado à terra (amostras Zona Agrícola, Zona Pecuária e Estação Ecológica). Para as três amostras, o modelo cinético obtido foi de pseudo-segunda-ordem. A amostra Zona Pecuária foi a que apresentou maior retenção (37,97.102 ug kg-1), logo uma dinâmica mais lenta. As demais amostras não apresentaram diferenças significativas para o processo sortivo (retenção de 29,07.102 e 31,67.102 ug kg-1 para as amostras Zona Agrícola e Estação Ecológica). Todos os sedimentos adsorveram de acordo com o modelo de Freundlich e suas isotermas foram classificadas como sendo do tipo C. A adsorção ocorreu com a formação de multicamadas e interações de natureza física (fisiossorção). O herbicida foi determinado via HPLC-UV. O método analítico foi validado de acordo com os documentos do INMETRO e da ANVISA e quando cabível de valores orientativos, os resultados obtidos se encontram em concordância. / On the threshold of 2012 the human population reached 7 billion of people. Only 12 years ago, 6 billion of human beings inhabited our planet. The growing and accentuated increase of the population has required an overuse of natural resources, especially the soil, main via for food production. Intending to increase the food production, without increasing the area under cultivation, pesticides are often used as an alternative. Nowadays herbicides are the pesticides most commonly traded, corresponding to a half of its market. Among the most common chemical groups, sulphonylureas have a noteworthy, the second most used class of herbicides throughout the world, however little studied in the context of analytical and environment chemistry. Once in the environment, the active principles of sulphonylureas may become a risk to the entire ecosystem. The sorption of herbicides in sediments determines how these will be retained in the matrix and how much will be available in soil solution, contaminating water resources. In this sense, this study aimed to realize studies for determinate the dynamics of chlorimuron ethyl (example of sulphonylurea herbicide family) in the environment. These studies were performed via kinetic and isotherm of absorptions in sediments. Sediments were compared with different characteristics depending of the use of earth (samples: Agricultural Zone, Farming Zone and Ecological Station). For all three samples, the obtained kinetic model was pseudo-second order. The farming Zone showed highest retention (37.97x102 ug kg-1), therefore a slower dynamic. The remaining samples didn\'t showed significant differences for the sorption process (retention of 29.07x102 and 31.67x102 ug kg-1 for Agricultural Zones and Ecological Stations). All sediments adsorbed according to Freundich\'s model and their isotherms were classified as C type. Adsorption occurred with the formation of multilayer and interactions were of physical type (physisorption). The herbicide was determined by HPLC-UV. The analytical method was validated in according with the INMETRO and ANVISA documents and, when appropriated of references values, the results have been in agreement.

Abstract According to recent clinical treatment, doctors give patients medicines based on clinical experience and biochemical data. However, biochemical data simply provides an initial physiology reaction. Although the data is enough for doctors to diagnose diseases, it does not help much for doctors to indicate the most useful medicine. Therefore, doctors will use the first line, cheap or low dose medicine to cure patients by previous clinical experience. It will not only extend the time of treatment but also lower the medical quality. Not to mention the side effects and increases the cost. Consequently, using SNP¡]Single Nucleotide Polymorphism¡^will help doctors to find out different patients¡¦ genotype and forecast the result of medicine. It will control disease efficiently and decrease the medical costs. Methods: This study will be discussed with an accurate test of how to check the genotypes of diabetes mellitus and predict the result of treatment from pharmacogenetic. The method was using PCR (Polymerase Chain Reaction) and RFLP (Restriction Fragment Length Polymorphism) to analyze patients¡¦ different genotype. Besides, this study uses the One-Way ANOVA to interpret the relationship between ABCC8-E16 and type 2 diabetes. In conclusion, the antidiabetic drugs- Sulfonylurea derivatives are suitable for ABCC8-E16 genotype patients. This result can be a reference for doctors to remedy diabetics. It will not only save the cost but also shorten the time of treatment, and it will impact deeply for personalized medicine in the future. type 2 diabetes, Sulfonylurea, SNP, PCR, RFLP, pharmacogenetic, personalized medicine

Thesis (Ph.D.). / Written for the Dept. of Epidemiology and Biostatistics. Title from title page of PDF (viewed 2008/05/09). Includes bibliographical references.

京都大学 / 0048 / 新制・論文博士 / 博士(農学) / 乙第12881号 / 論農博第2808号 / 新制||農||1028(附属図書館) / 学位論文||H26||N4880(農学部図書室) / 31599 / (主査)教授 冨永 達, 教授 奥本 裕, 教授 宮川 恒 / 学位規則第4条第2項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

Flazasulfuron is one of the newest sulfonylurea (SU) herbicides to be registered for use in the fine turf industry. Flazasulfuron is safe for use on bermudagrass (Cynodon dactylon), and zoysiagrass (Zoysia japonica) yet controls several grass, broadleaf, and sedge weeds. In fine turf, flazasulfuron controls cool-season grasses such as tall fescue (Festuca arundinacea) and perennial ryegrass (Lolium perenne) without harming warm-season grasses. Although SU herbicides like flazasulfuron bring several potential benefits to turfgrass markets, there are also several concerns related to using these herbicides in turfgrass areas. For many plant species, SU herbicides can cause phytotoxicity or death at less than 1 g ai/ha-1indicating small quantities of active ingredient are required to cause problems if herbicide moves in the environment. Herbicide moves to nontarget plants either after it has been applied via lateral relocation or during application via spray drift. Trials were conducted to evaluate flazasulfuron and trifloxysulfuron sodium tracking, runoff and drift in turfgrass environments. Field trials were conducted at six locations across the US to evaluate effects of irrigation, herbicide treatment, nontreated buffer distance, and time of tracking on creeping bentgrass (Agrostis stolonifera) putting green response to dislodged herbicide residues. Although average turf injury did not exceed 2%, significant differences were noted when treated plots were irrigated prior to tracking. In addition, putting green injury was negatively correlated and normalized difference vegetative index was positively correlated with increasing buffer distance. Data indicate the importance of post treatment irrigation to reduce lateral relocation of SU herbicides like flazasulfuron and trifloxysulfuron sodium in turfgrass. In other studies, herbicides were applied to turfgrass on 7 to 11 % slopes and perennial ryegrass injury was assessed at various distances down slope following an irrigation or rainfall event. Herbicide movement in runoff water was indicated by perennial ryegrass discoloration as much as 18 m below treated plots when excessive herbicide rates were applied to saturated soils. Based on perennial ryegrass injury, flazasulfuron at the rates tested was equivalent or more mobile than trifloxysulfuron sodium and equivalent or less mobile than pronamide when subjected to irrigation or rainfall soon after application to saturated soils. To assess spray drift, a bioassay based on corn height reduction was conducted and corn plants were exposed to potential spray drift in field conditions using conventional turfgrass spray equipment. A sprayer was operated when wind speeds were between 6.4 and 9.6 km h-1 and sentry plants were placed various distances between 0 and 30 m down wind. Wind speeds and direction were confirmed with anemometers and neutrally-buoyant balloons. Herbicide drift was not detected beyond 4.6 m downwind of either herbicide application. Data suggest a 5- to 8-m nontreated buffer area should sufficiently protect neighboring cool-season turfgrasses and other plants against flazasulfuron drift, runoff, and tracking as long as product is not applied to saturated soils and irrigated prior to traffic. / Master of Science in Life Sciences

<p>U okviru doktorske disertacije razvijena je brza i selektivna metoda za<br />određivanje i praćenje ostataka herbicida na bazi sulfonilurea (nikosulfuron,<br />oksasulfuron, tribenuron metil, tritosulfuron, triasulfuron, rimsulfuron i<br />prosulfuron) u zemlji&scaron;tu primenom visoko pritisne tečne hromatografije sa<br />UV detektor sa nizom fotoosetljivih dioda (HPLC-UV-DAD). Razdvajanje<br />sulfonilurea je izvedeno uz primenu Zorbax Eclipse XDB-C18 kolone. U cilju<br />definisanja odgovarajućih uslova analize, ispitan je i definisan uticaj<br />najznačajnijih eksperimentalnih faktora. Usvojeni su sledeći optimalni uslovi<br />gradijentne elucije: mobilna faza acetonitril (A) i 0,1% sirćetna kiselina (B) t<br />= 0 min, 52% A; t = 2-2,5 min, 47% A; t = 2,5-5 min, 52% A, pri konstatnom<br />protoku od 1 mL min-1 i temperaturi kolone od 250C. Na osnovu odziva<br />analitičkog signala, njegove reproduktivnosti i linearnosti, talasna dužina od<br />240 nm je usvojena kao odgovarajuća. Utvrđeno je da je uticaj matriksa bio<br />izražen te je stoga za kvantitativno određivanje sadržaja SU u uzorcima<br />zemlji&scaron;ta primenom HPLC-UV-DAD metode kori&scaron;ćena MMC kalibraciona<br />kriva. Pri analizi ekstrakata nekontaminiranog zemlji&scaron;ta ostvarena je granica<br />kvantitativnog određivanja za nikosulfuron, oksasulfuron, tribenuron metil,<br />tritosulfuron, triasulfuron, rimsulfuron i prosulfuron od 3,16 &mu;g kg-1, 3,40 &mu;g<br />kg-1, 3,76 &mu;g kg-1, 4,13 &mu;g kg-1, 3,60 &mu;g kg-1, 3,04 &mu;g kg-1 i 2,97 &mu;g kg-1,<br />redom. Za potrebe osetljivijih, selektivnijih i tačnijih određivanja SU u<br />zemlji&scaron;tu, definisana je metoda uz primenu tečne hromatografije sa<br />tandemskom masenom spektrometrijom (HPLC-MS-MS). HPLC-MS-MS je<br />kori&scaron;ćena kao referntna tehnika za proveru rezultata koji su dobijeni<br />primenom HPLC uz UV-DAD detektor. Definisan je efikasan postupak za<br />pripremu uzoraka zemlji&scaron;ta u cilju hromatografskog određivanja SU.<br />Najefikasnija ekstrakcija ostvarena je primenom sme&scaron;e dihlormetanacetonitril<br />(2:1, v/v), zaki&scaron;eljene sirćetnom kiselinom (0,8%, v/v), uz dodatak<br />uree (0,3 g/ 10g zemlji&scaron;ta). Postupak mikrotalasne estrakcije u zatvorenom<br />sistemu omogućio je najbolje uslove za ekstrakciju SU. U cilju izdvajanja SU,<br />iz matriksa ekstrakata zemlji&scaron;ta, primenjena je ekstrakcija na čvrstoj fazi (SPE) sa silika gelom kao adsorbensom. Definisana metoda za određivanje<br />ispitivanih SU, kao i razvijeni postupak pripreme uzoraka, uspe&scaron;no je<br />primenjen u analizi realnih uzoraka zemlji&scaron;ta. Veoma dobre vrednosti testa<br />povrata ostvarene pri analizi primenom HPLC-UV-DAD metode, potvrdile su<br />pre svega ispravnost postupka pripreme uzoraka, a delom i kompletne<br />metode. Tačnost razvijene metode za određivanje SU u zemlji&scaron;tu potvrđena je<br />paralelnim analizama uzoraka zemlji&scaron;ta kori&scaron;ćenjem HPLC-MS-MS.<br />Primenom Studentovog t-testa (upareni), utvrđeno je da se rezultati paralelnih<br />analiza statistički značajno ne razlikuju (P=95%). Istraživanja u okviru<br />disertacije obuhvatila su i praćenje disipacije nikosulfurona, rimsulfurona,<br />oksasulfurona i prosufurona u različitim komercijalnim dozama primene<br />tokom 50 dana u polju na tri različite dubine (0-15 cm, 15-30 cm i 30-45 cm),<br />kao i laboratorijskim uslovima na dve temperature (250C i 300C). Vreme<br />polurazgradnje (DT50) ispitivanih SU (nikosulfuron, oksasulfuron i<br />prosulfuron) definisano Mitttag-Lefler-ovom funkcijom u ogledima u<br />laboratorijskim uslovima na 250C iznosilo je 0,65 dana (50 g ha-1 a.k.), 0,64<br />dana (160 g ha-1 a.k.) i 0,66 dana (30 g ha-1 a.k.), redom, a na 300C za<br />nikosulfuron 0,20 dana (50 g ha-1 a.k.) i prosulfuron 0,49 dana (50 g ha-1 a.k.).<br />DT50 za ispitivane SU u polju, takođe definisano Mitttag-Lefler-ovom<br />funkcijom, iznosilo je 72 minuta (0,05 dana), 0,23 dana, 0,12 dana i 0,15<br />dana, za nikosulfuron, rimsulfuron, oksasulfuron i prosulfuron, redom.<br />Značajno veća disipacija koja je utvrđena istraživanjima u okviru ove<br />disertacije najverovatnije je uzrokovana uticajem abiotičkih i biotičkih<br />procesa, kao i faktora spolja&scaron;nje sredine.</p> / <p>In this thesis a fast and selective method for determination and monitoring<br />of residues sulfonylurea herbicides (SU) (nicosulfuron, oxasulfuron,<br />tribenuron methyl, tritosulfuron, triasulfuron, rimsulfuron and prosulfuron)<br />in soil, by applying high-performance liquid chromatography with UV<br />detector with diode array diodes (HPLC-UV-DAD) was developed. The<br />separation of the sulfonylurea was performed by use of a Zorbax Eclipse<br />XDB-C18 column. In order to define appropriate conditions of analysis,<br />the influence of the most significant the experimental factors was<br />investigated and defined. The following optimal conditions for gradient<br />elution: mobile phase acetonitrile (A) and 0.1% acetic acid (B) t = 0 min,<br />52% A; t = 2-2.5 min, 47% A; t = 2.5-5 min, 52% A were adopted at a<br />constant flow rate of 1 mL min-1 and column temperature of 250C. On<br />basis of the response of the analytical signal, its reproducibility and<br />linearity, the wavelength of 240 nm was adopted as an appropriate. The<br />influence of the matrix was expressed and therefore for the quantitative<br />determination of investigated SU in soil samples application of HPLCUV-<br />DAD methods was used MMC calibration curve. In the analysis of<br />extracts of nocontaminated soil limits of quantitation for nicosulfuron,<br />oxasulfuron, tribenuron methyl, tritosulfuron, triasulfuron, rimsulfuron and<br />prosulfuron was achieved 3.16 &mu;g kg-1, 3.40 &mu;g kg-1, 3.76 &mu;g kg-1, 4.13 &mu;g<br />kg-1, 3.60 &mu;g kg-1, 3.04 &mu;g kg-1 and 2.97 &mu;g kg-1, respectively. The method<br />by using liquid chromatography-tandem mass spectrometry (HPLC-MSMS)<br />was defined in order to find more sensitive, more selective and more<br />accurate way to determine concentration SU in soil. HPLC-MS-MS was<br />used as the reference technique for checking results that have been<br />obtained by HPLC with UV-DAD detector. An efficient procedure<br />preparation of soil samples for the purpose chromatographic determination<br />of SU was defined. Using a mixture of dichloromethane-acetonitrile (2: 1,<br />v / v), acidified with acetic acid (0.8%, v / v), with the addition of urea (0.3<br />g / 10 g soil) was applied as the most effective way for extraction SU.<br />Microwave extraction process in a closed system allowed the best<br />conditions for the extraction of SU. In order to extract SU from matrix<br />exctracts soil the solid phase the extraction (SPE) with silica gel as an<br />adsorbent was used. The defined method for determination of investigated SU, as well as the developed procedure of sample preparation, was<br />successfully applied in the analysis of real samples of soil. The correctness<br />of procedure of sample preparation was confirmed with very good values<br />of recovery test which was applied in the analysis by using HPLC-UVDAD.<br />The accuracy of the developed method for determination of SU was<br />confirmed by coupled analysis soil samples using HPLC-MS-MS. The<br />results of parallel analysis does not differ significantly at 95% confidence<br />level. It was obtained using Student t-test (paired). The method developed<br />in this thesis was used for monitoring the dissipation of nicosulfuron,<br />rimsulfuron, oxasulfuron prosufuron, in different commercial doses of<br />application during 50 days in field at three different depths (0-15 cm, 15-<br />30 cm and 30-45 cm) and for laboratory conditions at two temperatures<br />(25&ordm;C and 30&ordm;C). The half-life time (DT50) of investigated SU were<br />calculated by use of Mitttag-Lefler function in experiments under<br />laboratory conditions at 25&ordm;C. The values of DT50 for nicosulfuron,<br />prosufuron and oxasulfuron read: 0.65 days (50 g ha-1 a.k.), 0.64 days (160<br />g ha-1 a.k.) and 0.66 days (30 g ha-1 a.k.), respectively. In the same type of<br />experiments at 30&ordm;C we get DT50 for nicosulfuron equals 0.20 days (50 g<br />ha-1 a.k.) and for prosulfuron equals 0.49 days (50 g ha-1 a.k.). The values<br />of DT50 on experiments in field were obtain also by use of Mitttag-Lefler&#39;s<br />function, and half-life times for nicosulfuron, rimsulfuron, oxasulfuron and<br />prosufuron from the commercially recommended doses, equal 72 minutes<br />(0.05 days), 0.23 days, 0.12 days and 0.15 days, respectively. Significantly<br />greater dissipation which was determined in this thesis was probably<br />caused by the influence of abiotic and biotic processes as well as<br />environmental factors.</p>

A tolerância da cultura de milho aos herbicidas do grupo das sulfoniluréias, aplicados em condições de pós-emergência é variável em função do híbrido cultivado. Da mesma forma, tem sido observada tolerância diferencial ao nicosulfuron entre as cultivares de arroz melhoradas para tolerar os herbicidas imazethapyr + imazapic (AHAS-tolerante). Desta forma, este trabalho foi desenvolvido com o objetivo de avaliar: a seletividade do herbicida nicosulfuron, aplicado em condições de pós-emergência, a híbridos de milho e cultivares de arroz AHAS-tolerante. No experimento com a cultura do milho, foram estudados dez híbridos designados comercialmente por DKB 370, DKB 990, AG 6020, AG 9040, AS 1551, AS 1572, SWB 585, BX 1149, BM 620 e BM 128, sendo o delineamento experimental adotado em blocos casualizados, com cinco tratamentos e quatro repetições. Os tratamentos utilizados em g i.a. ha-1 foram: nicosulfuron + atrazina a 20 + 1500; nicosulfuron + atrazina a 40 + 3000; nicosulfuron a 50; nicosulfuron a 60, bem como a testemunha capinada, aplicados no estádio fenológico de quatros folhas expandidas (V4). Os híbridos que foram tolerantes a todos os tratamentos, não apresentando reduções de produção, foram DKB 370, AG 9040, AS 1551 e BM 620. Os tratamentos de nicosulfuron em mistura com atrazina nas doses de 20 + 1500 e 40 + 3000 g ha-1 de i.a. foram seletivos para todos os híbridos testados. As doses de nicosulfuron a 50 e 60 g i a ha-1 foram as mais fitotóxicas do experimento, os híbridos DKB 990, AG 6020, AS 1572, SWB 585, BX 1149 e BM 128 apresentaram redução de produção para ambas as dose. Para os híbridos AG 6020 e SWB 585 ocorreu diferenças de producão entre os tratamentos de nicosulfuron a 50 e 60 g i a ha- 1, o que indica suscetibilidade ao nicosulfuron. A tolerância ao nicosulfuron das duas cultivares de arroz AHAS-tolerante IRGA 422 CL e Puitá CL INTA foi testada em um outro experimento. Os tratamentos resultaram de esquema do tipo fatorial 2 x 8, em que duas foram as cultivares de arroz e oito foram as doses de nicosulfuron (0; 6,25; 12,5; 25; 50; 100; 200 e 400 g i.a.ha-1). Foram realizadas avaliações visuais de sintomas de fitotoxicidade aos 15 e 20 dias após a aplicação (DAA) e aos 20 DAA avaliou-se o comprimento de raiz, comprimento da parte aérea das plantas e massa seca de cada cultivar separadamente. Os dados foram submetidos à aplicação do teste F na análise da variância posteriormente a aplicação de regressões não lineares do tipo log-logístico. A cultivar IRGA 422 CL tolerou maiores doses de nicosulfuron quando comparada com a cultivar Puitá CL INTA. / The tolerance of the crop corn to the sulfonylurea herbicides, sprayed in post emergence conditions, is variable according to the hybrids that is cultivated. Likewise, it has been observed differential tolerance to nicosulfuron among rice cultivars bred to tolerate the herbicides imazethapyr + imazapic (AHAS-tolerant). Therefore, this research was developed in order to evaluate the selectivity of the herbicide nicosulfuron, sprayed in post emergence conditions, to corn hybrids and AHAS-tolerant rice cultivars. In the experiment with the crop corn, it was studied ten hybrids commercially designated as DKB 370, DKB 990, AG 6020, AG 9040, AS 1551, AS 1572, SWB 585, BX 1149, BM 620 e BM 128, being the experimental design adopted romdomized completely blocks, with five treatments and four replications. The treatments used in g a.i. ha-1 were: nicosulfuron + atrazine at 20 + 1,500; nicosulfuron + atrazine at 40 + 3,000; nicosulfuron at 50; nicosulfuron at 60, as well as a check weed free, sprayed in the phenological stage of four expanded leaves (V4). The hybrids that were tolerant to all treatments, with no yield reduction, were DKB 370, AG 9040, AS 1551 e BM 620. The treatments of nicosulfuron in mixture with atrazine at the rates of 20 + 1,500 e 40 + 3,000 g ha-1 of i.a. were selective to all hybrids tested. The rates of nicosulfuron at 50 and 60 g a.i. ha-1 were the least selective of the experiment, the hybrids DKB 990, AG 6020, AS 1572, SWB 585, BX 1149 and BM 128 showed yield reduction. For the hybrids AG 6020 and SWB 585 there were diferences in the yield among treatments of nicosulfuron 50 and 60 g a.i. ha-1, indicating low tolerance to nicosulfuron. The tolerance to nicosulfuron of the AHAS-tolerant rice cultivars IRGA 422 CL and Puita CL INTA was tested in another experiment. The treatments were obtained from a factorial design 2 x 8, with two rice cultivars and eight rates of nicosulfuron (0, 6.25, 12.5, 25, 50, 100, 200 and 400 g a.i.ha- 1). Visual observations of phytotoxicity symptoms were evaluated at 15 and 20 days after treatments (DAA) and at 20 DAA it was evaluated the root and shoot length and dry biomass of each cultivar separately. The data were submitted to F test in the analysis of variance followed by the application of non linear regressions log-logistic type. The cultivar IRGA 422 CL tolerated higher rates of nicosulfuron when compared to the cultivar Puita CL Inta.