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Qualidade fisiológica e rendimento de sementes de soja submetida a diferentes épocas de dessecação / Physiological quality and yield of soybean seeds subjected to different periods of desiccationWille, Anderson Luiz 19 May 2014 (has links)
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Previous issue date: 2014-05-19 / Sem bolsa / A dessecação é uma técnica que visa a antecipação da colheita, a fim de evitar que as sementes sofram danos excessivos, deterioração e redução da qualidade fisiológica em função do armazenamento em campo. Diante disso, o presente trabalho teve por objetivo verificar a época mais adequada para a aplicação de dessecante em diferentes estádios fenológicos da cultura da soja, bem como sua interferência sobre o rendimento final e a qualidade fisiológica das sementes produzidas. Para tanto, foram realizados 5 tratamentos com 5 repetições cada, em delineamento estatístico inteiramente casualizado, sendo os tratamentos: dessecação em R 6, em R 7.1, em R 7.3 e em R 8.2, além da testemunha - R 9 (sem dessecação). As amostras foram submetidas à análise através do teste de germinação, pelos parâmetros vigor de primeira contagem (%) e germinação (%); do teste de tetrazólio, considerando-se viabillidade (%), vigor (%) e deterioração por umidade (%) e do rendimento final, através do peso de mil sementes (g) e da produtividade (kg.ha-¹). Conclui-se que, se a finalidade da produção de uma lavoura de soja for sua utilização como semente, a melhor época para a dessecação com Diquat seria o estádio R 6, pela maior porcentagem de germinação e vigor; embora torne-se inviável em função dos danos causados no ato da colheita, principalmente pelo alto grau de umidade. Em contrapartida, se a finalidade for grão, a aplicação deve ser feita em estádios mais tardios, preferencialmente em R 8.2, em vista da uniformidade de maturação bem como maior produtividade. / The desiccation is a technique that aims hasten the harvest in order to prevent the seeds from suffering excessive damage, deterioration and loss in physiological quality as a function of the storage field. Therefore, this study aimed at assessing the most appropriate time for the application of Diquat desiccant at different growth stages of soybean, as well as their interference on final yield and physiological seed quality. For this, 5 treatments with 5 replicates in completely randomized design, with treatments were performed: desiccation in R 6, in R 7.1, in R 7.3 and in R 8.2, plus control - R9 (without desiccation). The samples were subjected to analysis by the germination test, by the parameters the vitality first count (%) and germination (%); tetrazolium test, considering feasibility (%), vitality (%) and damage caused by moisture (%) and the final yield, through the thousand seed weight (g) and yield (kg ha-¹). Conclude that if production of a crop a soybean for use as seed, the best time to desiccation with Diquat would be the R 6 stage, due to the higher germination and vigor; although it becomes unfeasible due to the damage caused at the time of harvest, mainly by high humidity. On the other hand, if the aim is grain, application should be made in later stages, preferably in R 8.2, in view of the uniformity of maturation and increased productivity.
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Dispersal and Management of Invasive Aquatic Plants in Mississippi WaterwaysFernandez, Amanda Louise 14 December 2013 (has links)
To understand the flow of water as a factor that influences aquatic vegetation communities and aquatic plant dispersal, custom-made Global Positioning System (GPS) drones were used to monitor the movement of water in Aliceville Lake, Columbus Lake, and Ross Barnett Reservoir, MS. In each reservoir, the drones drifted in the wind-generated surface current. Analysis of wind speeds suggests that a certain wind speed may be necessary to overcome gradient flow. Wind direction and wind speed should be incorporated in future spatial simulation models for aquatic plant dispersal and distribution. An herbicide evaluation on Cuban bulrush (Oxycaryum cubenese) was conducted to determine what herbicides would effectively control the invasive species. Applications made prelowering were more successful than postlowering applications for all herbicides tested with glyphosate, 2,4-D, triclopyr, diquat, imazamox, and imazapyr resulting in 100% mean biomass reduction. For postlowering applications, glyphosate, triclopyr, and diquat are recommended.
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Host-Guest Systems Based on Crown Ether, Cryptand, and Pseudocryptand Hosts with Paraquat, Diquat, Secondary Ammonium, and Monopyridinium Salt GuestsHuang, Feihe 25 March 2005 (has links)
Supramolecular host-guest chemistry is a topic of great current interest. However, the further development of host-guest chemistry is still limited by the number of available host-guest recognition motifs. This makes it necessary and valuable to find new host-guest recognition motifs and apply known host-guest recognition motifs in the preparation of novel supramolecular systems.
By comparing the crystal structures of the host and its taco complex, we proved that folding is a necessary step during the formation of taco complexes. Based on the known bis(m-phenylene)-32-crown-10/paraquat recognition motif, the first solid-state supramolecular poly(taco complex) was prepared.
We demonstrate not only that bis(m-phenylene)-32-crown-10-based cryptands are powerful hosts for paraquat derivatives compared with the simple crown ether, but also that cooperative complexation can be obtained with the cryptand structure. It was shown that the significant improvement in complexation was the result of the combination of the preorganization of the cryptand hosts and the introduction of additional and optimized binding sites. Furthermore, it was demonstrated that improved complexation of bis(secondary ammonium) and bisparaquat salts could also be achieved by the formation of the pseudocryptand structure. We also prepared two dimers of inclusion cryptand/paraquat complexes driven by dipole-dipole and face-to-face p-stacking interactions.
An interesting complex based on dibenzo-24-crown-10 and diquat was prepared. In its crystal structure the diquat guest lies in the concave cavity provided by two dibenzo-24-crown-8 hosts.
Monopyridinium-based [2]- and [3]-pseudorotaxanes were prepared based on the newly discovered bis(m-phenylene)-32-crown-10/monopyridinium salt and cryptand/monopyridinium salt recognition motifs.
Inspired by the formation of solid-state taco complexes between bis(m-phenylene)-32-crown-10 and paraquat derivatives, we designed and synthesized the first cylindrical bis(crown ether) host for paraquat derivatives and studied its complexation with paraquat.
We prepared three slow-exchange C3-symmetric inclusion complexes based on a newly discovered cryptand/trispyridinium recognition motif, in which 1,3,5-trispyridiniumbenzene salts act as guests.
Finally the application of several new and known recognition motifs in the preparation of a supramolecular poly[3]pseudrotaxane, and the first pseudorotaxane-type supramolecular star-shaped polymer, and the first supramolecular hyperbranched polymer was discussed. / Ph. D.
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Survival and Growth Responses of Lithobates Pipiens Tadpoles to anHerbicide and an Algaecide used to Control Aquatic Invasive PlantsThomas, Caitlin B. 24 July 2015 (has links)
No description available.
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Design, Preparation and Characterization of Novel Pseudorotaxanes, Semirotaxanes, Rotaxanes, Non-Covalent Supramolecular Polymers and PolycatenanesNiu, Zhenbin 17 October 2011 (has links)
Design and preparation of novel host/guest systems, such as pseudorotaxanes, semirotaxanes, rotaxanes and catenanes, with high association constants, enhanced yields and the abilities to respond to external stimuli are of great importance and significance due to their topological novelty and potential application. The convergence of supramolecular chemistry with polymer science provides an important way to extend the scope of polymer and material sciences by incorporating designed host/guest systems into polymers, and the resulting non-covalently linked supramolecular polymers are expected to have unusual properties due to their unique architectures compared with traditional polymers.
After discovery of bis(meta-phenylene)-32-crown-10 (BMP32C10) derivative/paraquat complexes, for about a quarter century only “taco”-shaped complexes were observed by X-ray crystallography. Here, by the self-assembly of a BMP32C10 bearing two electron-donating groups (carbazoles) with electron-accepting paraquat derivatives, the first [2]pseudorotaxane and the first pseudocryptand-type poly[2]pseudorotaxane based on BMP32C10 were isolated as crystalline solids as shown by X-ray analyses.
The first dual component pseudocryptand-type [2]pseudorotaxanes were designed and prepared via the self-assembly of synthetically easily accessible BMP32C10 pyridyl, quinolyl and naphthyridyl derivatives with paraquat. The formation of the pseudocryptand structures in the complexes remarkably improved the association constants by forming the third pseudo-bridge via H-bonding with the guest and π-stacking of the heterocyclic units.
A pseudocryptand-type [2]pseudorotaxane was formed via the self-assembly of a dipyridyl BMP32C10 derivative and a paraquat derivative. Due to the basicity of the pyridyl group, which forms the third pseudo-bridge of the pseudocryptand, this pseudorotaxane represents the first system with acid-base adjustable association constants, i. e., finite both under acidic and neutral conditions.
The first pseudocryptand-type supramolecular [3]pseudorotaxane was designed and prepared via the self-assembly of a bispicolinate BMP32C10 derivative and a bisparaquat. The complexation behavior was cooperative. In addition, the complex comprised of the BMP32C10 derivative and a cyclic bisparaquat demonstrated strong binding; interestingly, a poly[2]pseudocatenane structure was formed in the solid state for the first time.
Two novel BMP32C10 cryptands, bearing covalent and metal complex linkages, were designed and prepared. By employing the self-assembly of these biscryptands, which can be viewed as AA monomers, and a bisparaquat, which can be viewed as a BB monomer, the first AA/BB-type linear supramolecular polymers with relatively high molecular weights were successfully prepared.
Via the self-assembly of two BMP32C10-based cryptands, bearing covalent and metal complex (ferrocene) linkages, with dimethyl paraquat, novel [3]pseudorotaxanes were formed statistically and anticooperatively, respectively.
From a hydroxyl-functionalized secondary ammonium salt a [2]semirotaxane and a [2]rotaxane were prepared successfully with dibenzo-24-crown-8 (DB24C8). X-ray analysis of a single crystal of the [2]semirotaxane confirmed its semirotaxane nature. In addition, the formation of the [2]semirotaxane can be reversibly controlled by adding KPF6 and 18C6 sequentially. This system affords a way to prepare novel supramolecular polymers.
Dibenzo-30-crown-10 (DB30C10) derivatives and pyridine-based DB30C10 cryptands were prepared by employing the templating method established by our group. A [2]pseudorotaxane was prepared based on DB30C10 diol and paraquat diol. The [3]pseudorotaxane formed via the self-assembly between DB30C10 cryptand and bisparaquat diol occurred in a cooperative manner. In addition, a bromo-functionalized DB30C10 cryptand was successfully designed and prepared. An alkyne-functionalized DB30C10 cryptand was designed and is under preparation; its precursors have been prepared successfully. In the future, based on these functionalized cryptands and paraquat salts, AA and AB type monomers will be prepared. Via the self-assembly between these monomers, non-covalent supramolecular polymers with high molecular weight will be afforded.
A novel DB30C10 cryptand bearing an organometallic bridge, ferrocene, was prepared via 1-(3'-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDCI) coupling of the crown ether diol with ferrocene dicarboxylic acid. The cryptand is dimerized in the solid state via π, π-stacking and hydrogen bonds. The ferrocene-based cryptand formed novel [2]pseudorotaxanes with paraquat and diquat PF₆ salts with association constants (Kₐ) of 1.7 ± 0.1 x 10³ and 4.2 ± 0.3 x 10⁴ M⁻¹ in acetone-d₆, respectively.
In order to prepare linear polycatenanes, the preparation of which represent a real synthetic challenge, a series phenanthroline derivatives were designed and prepared. A “U” shaped monomer was successfully prepared in relative high yield with good solubility. In the future, real linear polycatenanes will be prepared. In addition, a novel diphenanthroline-based BMP32C10 derivative was prepared in high yield and the complexation behavior between it and dimethyl paraquat was studied. / Ph. D.
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