Photocopy of typescript. / Digitized by Kansas Correctional Industries

Orientador: Massanori Takaki / Banca: Victor José Mendes Cardoso / Banca: José Eduardo Zaia / Resumo: O objetivo deste trabalho foi conhecer os aspectos envolvidos na germinação de sementes de Tibouchina mutabilis (Vell.) Cogn. (Melastomataceae), espécie característica da encosta úmida da Serra do Mar que ocorre do Rio de Janeiro até Santa Catarina na floresta pluvial da encosta Atlântica. De acordo com a literatura, a espécie é encontrada quase que exclusivamente na mata secundária, onde chega por vezes constituir-se na espécie dominante. Os parâmetros analisados foram: porcentagem final de germinação, velocidade média, o tempo médio e o índice de sincronização e, para maturação, também foi analisada a morfologia do embrião. A faixa ótima de temperatura que proporcionou os melhores valores de porcentagem e velocidade de germinação foi de 25 a 30ºC e na alternância de temperaturas, sob fotoperíodo de 12 horas foi de 20-25°C. As sementes foram sensíveis a luz germinando preferencialmente sob fotoperíodos longos 8 a 12 horas, sendo a quantidade da luz fornecida, determinante na velocidade de germinação, enquanto que a qualidade da luz influenciou as porcentagens finais de germinação, que foi maior nas condições de fotoequilíbrio do fitocromo altos. As sementes embebem no escuro, mas não germinaram na ausência de um período mínimo de 96h de luz. A capacidade germinativa ocorreu com 14 dias pós-antese e a máxima germinação foi atingida aos 21 dias. Observou-se que o melhor indicador de maturação fisiológica para a espécie é o início da abertura natural das cápsulas. Estas características apresentadas indicam que T. mutabilis é uma espécie com características típicas de pioneira / Abstract: The objective of this work was to know the aspects involved in seed germination Tibouchina mutabilis (Vell.) Cogn. (Melastomataceae), feature species of Serra do Mar, occurring from Rio de Janeiro to Santa Catarina, Brazil in Atlantic Forest. The species is found mostly in secondary forest sometimes consisting the dominant species. It was analyzed the final percentage of germination, mean germination rate and daily relative frequency and the synchronization index; It was analyzed the morphology of the embryo and germination capacity during maturation. The range of optimum temperature to germination was of 25 to 30ºC and in the alternating temperature of 20-25°C. The seeds of T. mutabilis were sensitivity to the light, the germination happened preferentially under long photoperiod of 8 to 12h, increase in the light fluence increase the germination rate and increase in the photoequilibrium of phytochrome increase the final percentage germination. The seeds of the T. mutabilis imbibed in darkness, but did not germinate on absence of a minimum period of light 96 hours. The germination capacity appeared in 14 days stage of development, whose embryo in some seeds were partially developed, and the maximum germination capacity was reached in 21 days stage, whose embryo full up the capsule. The best indicator of physiological maturation to this specie is natural open beginning of the capsule. The results showed that T. mutabilis is a pioneer, absolute positive photoblastic specie / Mestre

Extensive areas of potentially productive but depleted range land in the United States are occupied by a weed commonly known aa cluster tarweed (Madia glomerata). Moat attempts at seeding these areas to useful forage plants have resulted in failure. Many of these failures have been attributed to the vigorous competitive growth of tarweed plants. More recent observations of seedings in tarweed areas and laboratory work at the University of Utah indicate that tarweed is not only a strong competitor but may also produce substances which inhibit the germination and growth of other species of plants.

Seed vigor, although not well understood, is a key critical component for yield and is in part due to a well establishment and vigorous stand of canola (<i>Brassica napus</i>) seedling under less than ideal conditions in Western Canada. My objective was to determine what constitutes vigor by studying the response of a black seed line and a yellow seed line imbibed at 8 ºC in either water, saline or osmotic solutions, abscisic acid (ABA), ABA biosynthesis inhibitor, gibberellin (GA4+7), inhibitor of GA biosynthesis and a germination promoter, fusicoccin. Also tested was the effect of seed coat (testa) on seed germination rate and percent germination. Previous studies have established that seed vigor is in part hormonal controlled and genetically controlled. In our study, gene expression was investigated by using transcriptome analysis and hormonal analysis was used to quantitate the changes in hormones and their metabolites during germination. <p> Both the black and the yellow canola seed lines were very sensitive to increasing concentrations of saline and osmotic solutions; however, at the same osmotic potential, osmotic solutions were more inhibitory. The yellow seed line was more sensitive to these conditions than the black seed line. As expected, ABA delayed seed germination, whereas GA4+7 enhanced seed germination and GA4+7 partially overcame the inhibitory effect of ABA. The seed coat was a major factor affecting the germination rate of the yellow seed line; however, GA4+7 overcame the inhibitory effect of the seed coat, whereas ABA exacerbated it. Fusicoccin was more stimulatory to germination than GA4+7; however, unlike GA4+7, it was unable to overcome the inhibitory effect of paclobutrazol, a GA biosynthesis inhibitor. Fluridone, an ABA biosynthesis inhibitor, was unable to overcome the inhibitory effects of a saline solution suggesting that the inhibitory effect was not due to elevated ABA levels. Ethylene, a stimulator of germination, did not appear to be involved in the germination of these two lines. Controlled deterioration at 35 ºC, 85% RH was either partially or completely overcome by exogenous GA4+7. This study demonstrates that the role of hormones, salinity and seed coat on the germination of canola seed under low temperature environmental conditions. <p>During germination, ABA declined while GA4 increased. Higher ABA was found in un-germinated seeds compared to germinated seeds. GA4+7 was lower in seeds imbibed in the saline solution compared to seeds imbibed in water. Un-germinated seeds imbibed in ABA had lower GA4+7 compared to un-germinated seeds imbibed in water; however, the contents of GA4+7 were similar for germinated seeds imbibed in either water or ABA. Phaseic acid (PA) and dihydrophaseic acid (DPA) increased in seeds imbibed in either water, the saline solution or ABA, while they decreased in seeds imbibed in GA4+7. In addition, we found that ABA inhibited GA4 biosynthesis, whereas, GA had no effect on ABA biosynthesis, but altered the ABA catabolic pathway. <p> Gene expression profiles revealed that there are significant differences between un-germinated and germinated seeds. Seeds imbibed in water, GA4+7, a saline solution or ABA had different gene profiles. LEA genes, hormone-related genes, hydrolase-related genes and specific seed germination-related genes were identified and their expression profiles were finely associated with seed germination performance.

Disinfestation using microwaves can be an alternate to chemical methods of killing insects in grain. A pilot-scale industrial microwave dryer operating at 2.45 GHz was used to determine the mortality of life stages of Tribolium castaneum (Herbst), Sitophilus granarius (L.) and Cryptolestes ferrugineus (Stephens) adults in wheat, barley, and rye. Grain samples of 50 g each at 14, 16, and 18% moisture content were infested with stored-grain insects. The samples were then exposed to microwave energy at 200, 300, 400, and 500 W for exposure times of 28 and 56 s. Complete (100%) mortality was achieved for adults of three insect species at 500 W, 28 s and at 400 W, 56 s in barley and wheat. In rye, complete mortality of adult T. castaneum and S. granarius was achieved at 400 W, 28 s and at 300 W, 56 s whereas for C. ferrugineus, complete mortality was achieved at 500 W, 28 s and at 400 W, 56 s. The average temperature of wheat, barley, and rye at 500 W and 28 s was around 80, 71 and 82oC, respectively, and moisture loss was 2.0, 1.9 and 2.5 percentage points, respectively. Among the life stages of T. castaneum in wheat, eggs were the most susceptible followed by larvae, and the least susceptible were the pupae and adults. Among the life stages of T. castaneum in barley and rye, eggs were the most susceptible and adults were the least susceptible with no significant difference between pupae and larvae. There was no significant difference in the mortality of adults at 14, 16, and 18% moisture content barley and rye and the life stages of T. castaneum and S. granarius in rye. Germination of seeds decreased with an increase in power level or exposure time or both. There was no significant difference in the quality characteristics of microwave-heated wheat and rye except for reduced flour yield in rye. The quality of the barley treated at 500 W, 28 s was the same as the control, whereas, there was significant decrease in the quality of barley treated at 400 W, 56 s. / May 2009

Seed vigor, although not well understood, is a key critical component for yield and is in part due to a well establishment and vigorous stand of canola (<i>Brassica napus</i>) seedling under less than ideal conditions in Western Canada. My objective was to determine what constitutes vigor by studying the response of a black seed line and a yellow seed line imbibed at 8 ºC in either water, saline or osmotic solutions, abscisic acid (ABA), ABA biosynthesis inhibitor, gibberellin (GA4+7), inhibitor of GA biosynthesis and a germination promoter, fusicoccin. Also tested was the effect of seed coat (testa) on seed germination rate and percent germination. Previous studies have established that seed vigor is in part hormonal controlled and genetically controlled. In our study, gene expression was investigated by using transcriptome analysis and hormonal analysis was used to quantitate the changes in hormones and their metabolites during germination. <p> Both the black and the yellow canola seed lines were very sensitive to increasing concentrations of saline and osmotic solutions; however, at the same osmotic potential, osmotic solutions were more inhibitory. The yellow seed line was more sensitive to these conditions than the black seed line. As expected, ABA delayed seed germination, whereas GA4+7 enhanced seed germination and GA4+7 partially overcame the inhibitory effect of ABA. The seed coat was a major factor affecting the germination rate of the yellow seed line; however, GA4+7 overcame the inhibitory effect of the seed coat, whereas ABA exacerbated it. Fusicoccin was more stimulatory to germination than GA4+7; however, unlike GA4+7, it was unable to overcome the inhibitory effect of paclobutrazol, a GA biosynthesis inhibitor. Fluridone, an ABA biosynthesis inhibitor, was unable to overcome the inhibitory effects of a saline solution suggesting that the inhibitory effect was not due to elevated ABA levels. Ethylene, a stimulator of germination, did not appear to be involved in the germination of these two lines. Controlled deterioration at 35 ºC, 85% RH was either partially or completely overcome by exogenous GA4+7. This study demonstrates that the role of hormones, salinity and seed coat on the germination of canola seed under low temperature environmental conditions. <p>During germination, ABA declined while GA4 increased. Higher ABA was found in un-germinated seeds compared to germinated seeds. GA4+7 was lower in seeds imbibed in the saline solution compared to seeds imbibed in water. Un-germinated seeds imbibed in ABA had lower GA4+7 compared to un-germinated seeds imbibed in water; however, the contents of GA4+7 were similar for germinated seeds imbibed in either water or ABA. Phaseic acid (PA) and dihydrophaseic acid (DPA) increased in seeds imbibed in either water, the saline solution or ABA, while they decreased in seeds imbibed in GA4+7. In addition, we found that ABA inhibited GA4 biosynthesis, whereas, GA had no effect on ABA biosynthesis, but altered the ABA catabolic pathway. <p> Gene expression profiles revealed that there are significant differences between un-germinated and germinated seeds. Seeds imbibed in water, GA4+7, a saline solution or ABA had different gene profiles. LEA genes, hormone-related genes, hydrolase-related genes and specific seed germination-related genes were identified and their expression profiles were finely associated with seed germination performance.

Thesis (M. Sc.)--University of Hong Kong, 1972. / Typewritten.

Thesis--Auburn University, 2010. / Abstract. Includes bibliographic references.

No description available.

No description available.