Master of Science / Department of Agronomy / Anita Dille / A better understanding of kochia (Kochia scoparia) seed characteristics is necessary for long term management of this increasingly troublesome weed. The objectives were to evaluate maternal environmental factors influencing kochia seed produced in the field and to document variability in dormancy and seed viability produced within a single kochia plant grown in the greenhouse or field. Field experiments were conducted in 2012 and 2013 at the Kansas State Agricultural Research Center in Hays. Two different kochia biotypes from Hays were planted with and without five canopy types, namely corn, soybean, grain sorghum, wheat stubble, and kochia plants. A greenhouse experiment with two generations (F1 and F2) of self-pollination was conducted with the same kochia biotypes. Date of initial flowering and final plant heights were recorded. Plants were harvested when seed was mature and divided into three equal parts (top, middle, and bottom). Seeds were cold treated or not, and approximately 50 seeds were placed in petri dishes with water for germination counts taken over six weeks. Viability of remaining seeds were then tested. For field-grown kochia, plants were taller in corn, sorghum and weedy canopies compared to the absence of a canopy. Seed germination from field grown kochia ranged between 77 and 100% for both treatments. There was reduced germination in the presence of a weedy canopy for both treatments and biotypes (77 to 82%) compared to the absence (93 to 99%), with an increase in hard viable seed in the presence of weedy canopy (5 to 14%). In the greenhouse, the F2 generation produced more immediately germinable seed compared to the F1 generation which had more seed with delayed germinability. Seed from bottom third of F1 and F2 plants had greater total germination (73 and 70%, respectively) compared to the middle (61 and 65%) and top (50 and 59%) thirds of the plant. There was a maternal environmental effect on kochia seed characteristics with implications on generating persistent seed for the future seedbank.

Doctor of Philosophy / Department of Agronomy / Johanna A. Dille / Kochia (Kochia scoparia L. Schrad.), one of the most problematic weeds in the Great Plains of United States, has evolved resistance to some herbicides including glyphosate (5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) inhibitor) which was first reported in western Kansas in 2007. The objectives of this research were to (1) characterize six kochia populations from western Kansas on the basis of glyphosate resistance or multiple herbicide resistance, (2) determine germination characteristics of the populations and evaluate their growth and fecundity in the field, and (3) determine if EPSPS gene amplification responsible for glyphosate resistance in kochia was associated with growth and fecundity cost in the plants. Six kochia populations were from Scott, Finney, Thomas, Phillips, Wallace, and Wichita counties. Based on shikimate assay for glyphosate and recommended field rates for four tested herbicides, three kochia populations (Scott (SC-R), Finney (FN-R), and Thomas (TH-R)) were grouped into glyphosate-resistant (GR) and three populations (Phillips (PH-S), Wallace (WA-S) and Wichita (WI-S)) were grouped into glyphosate-susceptible (GS). All populations were resistant to dicamba (synthetic auxin) and chlorsulfuron (acetolactate synthase inhibitor), however, atrazine (PS II inhibitor) resistance in FN-R was noted as exceptional among the GR populations. Across the three germination temperatures (5, 10 and 15 C), the GR populations consistently had less total cumulative germination and at 15 C, they consistently required more time to attain 50% of maximum cumulative germination than the GS populations. Both the field study and evaluation of relationship between EPSPS gene amplification and plant performance showed that differences in plant height, biomass accumulation and fecundity among populations were not in respect to glyphosate resistance but rather, differences in their inherent ability to grow and produce seeds in the presence or absence of neighbors. This research suggests that fitness differences between GR and GS kochia populations could be identified in germination characteristics but not in their growth or fecundity.

The release of the seed eating beetle Sulcobruchus subsuturalis for biological control of Caesalpinia decapetala in South Africa has been ongoing since 2000. This is the first post release evaluation of the efficacy of the agent against the weed. The study assessed the phenology of C. decapetala and S. subsuturalis at two sites and included determining the establishment of the beetle on the target weed at 25 study sites. In addition, the effects of S. subsuturalis on seed densities as well as seed germination and seedling recruitment were examined. Furthermore predation by native ants and attacks by native parasitoids were also examined at two release sites. Mature filled pods were available on the tree from September (spring) to March (summer) when the beetle is expected to be reproductively active. The majority of beetle releases by Working for water took place in summer. However the proportion of beetle infested seeds, which were only recovered inside pods in the tree canopy at study sites, was low (0 to 15.5%). Consequently high seed densities and seedling recruitment were observed in the field. In the laboratory, S. subsuturalis did not lay eggs on buried seeds, however seed infestation levels were generally high. Only 8.3% of the seeds containing adults germinated and 6.3% emerged into seedlings. Of the seeds containing larvae, only 14.6% germinated and 2.1% emerged into seedlings. Thus far, S. subsuturalis has failed to maintain high populations on the target weed, possibly due to egg predation by native ants (Crematogaster species, Pheidole megacephala, Messor natalensis and Tetramorium avium) and attacks by native parasitoids. Egg predation reached 100% within 10 days. Egg parasitism by unknown parasitoids ranged between 80 and 93.1% in Limpopo. The parasitic wasp Dinarmus altifrons was recovered once developing inside a C. decapetala seed infested with S. subsuturalis. Further investigations regarding attacks by indigenous parasitoids on S. subsuturalis are required to determine the extent of this problem. Meanwhile releases of S. subsuturalis against C. decapetala should continue. However release efforts need to be improved by (a) using inundative rather than inoculative releases (b) Releasing every year between September and March (summer) and (c) involving land owners, farmers and nature reserve authorities in release activities. Ultimately an additional agent should be sought for release against C. decapetala as the weed may not be the preferred host for S. subsuturalis.

As espécies do gênero Smilax L., conhecidas popularmente como salsaparrilha, são empregadas na medicina popular desde o século XVI, porém essas plantas ainda são exploradas de maneira extrativista. Com o aumento da comercialização de plantas medicinais cresce a necessidade de trabalhos que certifiquem a qualidade da matéria prima. A caracterização anatômica e o perfil químico certamente fornecem uma base mais segura nessa certificação. Visando auxiliar no atendimento da demanda e apontar propostas do manejo sustentável em áreas de ocorrência natural de Smilax fluminensis Steud. os objetivos do presente estudo foram: a) analisar a morfoanatomia dos órgãos vegetativos e indicar as características de valor diagnóstico para essa espécie; b) analisar o perfil químico de S. fluminensis através da Cromatografia Líquida de Alta Eficiência acoplada com Detector de Arranjo de Diodos utilizando-se extratos metanólicos (EMeOH) de raízes, rizóforos e ramos aéreos; c) realizar estudos de germinação de sementes e de propagação vegetativa por estacas de ramos aéreos e subterrâneos e, d) acompanhar ao longo de um ano a capacidade de rebrotamento das plantas no campo. As análises ao microscópio de luz foram realizadas utilizando-se as técnicas usuais para o preparo de lâminas semipermamentes e permanentes. Para as análises no microscópio eletrônico de varredura, amostras de folhas foram fixadas em Karnovsky, desidratadas em série etílica e submetidas ao método do ponto crítico de CO2, montadas sobre suportes de alumínio e metalizadas. As sementes foram submetidas a diferentes temperaturas, sob fotoperíodo diário de oito horas e na ausência de luz. Para o enraizamento de estacas, foram utilizados ramos aéreos e subterrâneos com aproximadamente 20 cm, com duas regiões nodais submetidas ao tratamento com ácido indolbutírico a 100 ppm ou apenas em água destilada. Dentre os caracteres anatômicos que permitiram a delimitação da espécie destacam-se: estômatos anisocíticos e paracíticos presentes na epiderme da face abaxial; cera epicuticular na forma de grânulos globosos; mesofilo homogêneo com ampla câmara subestomática; presença da bainha amilífera nos primeiros entrenós do caule aéreo; presença de endoderme com reforço em U; ausência de meristema de espessamento no rizóforo adulto; presença de exoderme com estrias de Caspary nas raízes brancas e ausência de córtex interno nas raízes marrons. Em relação ao perfil químico, os extratos obtidos apresentaram picos correspondentes às substâncias: ácido clorogênico, ácido cafeico, rutina, ácido p-cumárico, ácido ferúlico e ácido trans-cinâmico. As melhores porcentagens de germinação foram 80% em 20-30º C no claro e 85% a 30ºC no escuro. Apenas as estacas de ramos subterrâneos enraizaram. Ao final de um ano de acompanhamento das plantas no campo, todas apresentaram em média 4.05 novos brotamentos. As espécies cujas partes utilizadas para o preparo dos medicamentos são as raízes correm maior risco de extinção como é o caso de S. fluminensis. Portanto, a capacidade de propagação por sementes, por estacas e de regeneração de ramos aéreos após a remoção de parte das estruturas subterrâneas aliada ao perfil químico confirma o seu potencial para a exploração econômica de maneira sustentável, sendo uma alternativa para reduzir o extrativismo predatório dessa espécie nativa. / The Smilax L. species, popularly known as salsaparrilha, have been used in folk medicine since the sixteenth century; however, these plants have still been handled in extractive way. With the increasing commercialization of medicinal plants, there is need to study to certify the raw material quality. Anatomical analyses and chemical profile characterization certainly provides a more secure basis to this certification. Aiming to meet the demand and to point proposals for sustainable management of natural occurrence of Smilax fluminensis Steud., the objectives of this study were: a) to analyze the morph-anatomy of vegetative organs and indicate the features of diagnostic value for this species, b) to examine the chemical profile of S. fluminensis by High Performance Liquid Chromatography Coupled with Diode Array Detector using methanol extracts (EMeOH) of roots, rhizophore and stems c) to conduct studies of seed germination and vegetative propagation on cuttings of aerial and subterranean stems and d) to monitor, over a year, the resprouting ability of plants in the field. We carried out the analyses under a light microscopy using the usual techniques for preparing semi-permanent and permanent slides. To perform the analyses under a scanning electron microscopy, leaf samples were fixed in Karnovsky, dehydrated in ethanol series and subjected to critical point method of CO2, mounted on aluminum supports and coated with gold. Seeds were exposed to different temperatures under a daily photoperiod of eight hours and in the absence of light. To analyze the sprouting, aerial and subterranean stems were used with about 20 cm of length, with two nodal regions subjected to treatment with IBA at 100 ppm or in distilled water. Among the anatomical features that enable delimitation of the species are: anisocytic and paracytic stomata in the epidermis of the abaxial surface, epicuticular wax in the form of granules globules, homogeneous mesophyll with large substomatal chambers, presence of starch sheath in the first internodes of the aerial stem, the presence of endoderm-reinforced U and the absence of primary thickening meristem in the adult rhizophore, exodermis with Casparian strips in roots, and the absence of inner cortex in brown roots. Regarding the chemical profile, extracts showed peaks corresponding to the following substances: chlorogenic acid, caffeic acid, rutin, p-coumaric acid, ferulic acid and trans-Cinnamic acid. The best germination was 80% at 20-30ºC under light and 85% at 30ºC in the dark. Only roots sprouted. After one year of monitoring the plants in the field, all had an average of 4.05 new aerial shoots. The species whose roots are used for the preparation of medicines face a greater risk of extinction as is the case of S. fluminensis. Therefore, the ability to spread by seeds, cuttings and shoots regeneration after removal of aerial stems combined with the chemical profile confirms its potential for economic use in a sustainable manner, and an alternative to reduce the predatory extraction of native species.

A pesquisa teve como objetivo estudar procedimentos para a condução dos testes de deterioração controlada, envelhecimento acelerado, condutividade elétrica e lixiviação de potássio, procurando-se verificar sua eficiência para identificação de diferentes níveis de vigor de lotes de sementes de melão (Cucumis melo L.). Para tanto, o estudo foi conduzido em duas etapas, utilizando-se cinco lotes de sementes dos híbridos AF-646 e AF-682. Na primeira foram realizados os testes de germinação, primeira contagem de germinação, Método Agroflora, emergência de plântulas em casa de vegetação e estudos específicos para os testes de deterioração controlada (graus de umidade de 18%, 21% e 24%, a 45ºC, durante 24 e 48 horas), de envelhecimento acelerado, com e sem solução salina (períodos 48, 72 e 96 horas, a 38ºC ou 41ºC), de condutividade elétrica (temperaturas de 20ºC, 25ºC e 30ºC, volumes de 50 e 75mL de água, 25 e 50 sementes e períodos de 1, 2, 4, 8, 12, 16, 20 e 24 horas) e de lixiviação de potássio (25 e 50 sementes, 50 e 75mL de água, a 25ºC e 30ºC, durante 30, 60, e 90 minutos, 2h, 2h e 30 minutos, 3, 4 e 5 horas). Os procedimentos considerados mais promissores para cada teste, nesta primeira fase, foram comparados na segunda etapa, que também incluiu os testes de germinação, primeira contagem de germinação, Método Agroflora e emergência de plântulas em casa de vegetação. Diante dos resultados obtidos, concluiu-se que os testes de deterioração controlada (24%/45ºC/24h) e de envelhecimento acelerado (procedimento tradicional e com solução salina), utilizando a combinação 41ºC/72h, apresentam sensibilidade suficiente para avaliação do potencial fisiológico de sementes de melão. O teste de condutividade elétrica não constitui em opção eficiente para avaliação do vigor das sementes, enquanto o teste de lixiviação de potássio necessita de estudos adicionais para adequar sua metodologia e viabilizar a sua utilização para sementes de melão, considerando-se, inclusive, os prováveis efeitos do genótipo. / This research was conducted to study and select procedures for the controlled deterioration, accelerate aging, electrical conductivity and potassium lixiviation tests, to verify their sensitivity to identify different vigor levels of melon (Cucumis melo L.) seed lots. Five seed lots each from the hybrids AF-646 and AF-682 were used. In the first experimental stage, the following tests were performed: germination, germination first count, Agroflora Method and seedling emergence. Specific studies were also conducted to the following tests: controlled deterioration (seed moisture content of 18%, 21% and 24%, at 45ºC, for 24 and 48 hours), traditional accelerated aging, saturated salt accelerated aging (for 48, 72 and 96 hours, at 38 o C or 41 o C), electrical conductivity (25 or 50 seeds imbibed in 50mL or 75mL water, 20 o C, 25 o C and 30 o C, for 1, 2, 4, 8, 12, 16 and 20 hours) and potassium leachate (25 or 50 seeds, imbibed in 50mL and 75mL, at 25 o C and 30 o C, for 30, 60, 90, 120, 150, 180, 240 and 300 minutes). The procedures considered the most promising for each test in the first stage were compared, in the second stage. The later stage also included germination, germination first count, Agroflora Method and seedling emergence tests. From the results, it was concluded that controlled deterioration (24%/45 o C/24h) and accelerate aging (traditional procedure and salt saturated) tests, using the 41 o C/72h combination, showed to be sufficiently sensitive for the evaluation of the physiological potential of melon seeds. The electrical conductivity test does not constitute an efficient option for the vigor evaluation, while the potassium lixiviation test needs further studies in order to adjust its methodology and enable its use for melon seeds, also considering the probable genotype effects.

O presente trabalho foi realizado visando estabelecer metodologia para o teste de germinação e verificar a possibilidade de uso do teste de raios-X para avaliar a qualidade de sementes de aroeira-branca. Foram utilizados quatro lotes de sementes colhidas em áreas da região sul de Minas Gerais, no ano de 2001. As condições de execução do teste de germinação foram determinadas com base nas percentagem e velocidade de germinação das sementes sob nove faixas de temperatura em um gradiente linear entre 15 e 35 °C e sobre os substratos papel mata-borrão, areia e vermiculita. Para o teste de raios-X, as sementes foram radiografadas e classificadas em função do estádio de desenvolvimento e da morfologia, normal e anormal, dos embriões; após o teste de germinação, procedeu-se a comparação da anatomia das sementes com as respectivas plântulas/sementes resultantes. Os resultados permitiram concluir que: (1) o teste de germinação deve ser conduzido a 27 °C, sobre substrato vermiculita e as contagens efetuadas aos 20 e 45 dias após sua instalação; (2) o teste de raios-X é eficiente na detecção de danos e anormalidades nos embriões prejudiciais à germinação. / The present work was carried out with the objective to establish a methodology for the germination test and to verify the possibility to use the X-rays in the evaluation of 'aroeira-branca' seed quality. Four seed lots collected in different places in the south region of the State of Minas Gerais in 2001 were used. The conditions for performing the germination test were determinated basing on the percentage and on the rate of seed germination under nine ranges of temperature in a linear gradient between 15 and 35°C and on substrates of blotters, sand and vermiculite. For the X-ray test, radiography of seeds were made as well as classification in relation to stage of development and morphology, normal and abnormal, of embryo; the germination test was run aiming to detect possible relationship between seedlings/seeds and the respective anatomy as revealed by radiographic pictures. It was concluded that the germination test for 'aroeira-branca' seeds may be run at 27 °C on vermiculite substrate; records have to be made on twenty and forty-five days after the begining of the test. The X-ray test was seen to be able to detect successfully damages and abnormalities in embryos of 'aroeira-branca' seeds.

Made available in DSpace on 2014-06-11T19:30:58Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-04-15Bitstream added on 2014-06-13T19:01:06Z : No. of bitstreams: 1 simao_e_dr_rcla.pdf: 1042430 bytes, checksum: d22cdd3ae2be9d5d0c52334b9d702626 (MD5) / As metodologias propostas nos programas de recuperação de áreas degradadas têm demonstrado que uma das grandes dificuldades encontradas na recomposição de determinadas formações vegetais, é a falta de conhecimento das características adaptativas de cada espécie. Neste contexto, o objetivo do estudo foi conhecer os aspectos ecofisiológicos da germinação, sobrevivência e desenvolvimento inicial de Styrax camporum Pohl. (Styracaceae) sob diferentes condições hídricas e de solo, em condições controladas e no ambiente natural. Para tanto, foram avaliados em laboratório: influência do estresse hídrico, temperatura e luz sobre a germinação, sobrevivência e desenvolvimento inicial de S. camporum; tamanho das sementes; temperaturas constantes de 10 a 45 °C com intervalo de 5 °C; diferentes condições de luz; estresse hídrico (variações do potencial de água em três temperaturas a 20, 25 e 30°C); efeito da condição de luz, substrato e conteúdo de água no desenvolvimento inicial. Em campo, foram avaliadas: emergência; simulação de um banco de sementes; sobrevivência e desenvolvimento de mudas plantadas sob um gradiente de luz e umidade. A faixa ótima de temperatura para germinação de sementes foi de 25 a 30°C, sobre o substrato vermiculita. As sementes da espécie foram insensíveis a luz branca embora sob baixa razão V/VE a porcentagem de germinação foi menor. A heterogeneidade de tamanho das sementes não resultou em diferenças na porcentagem final de germinação As sementes de S. camporum apresentaram redução significativa da porcentagem de germinação sob baixo potencial de água. Os resultados indicam que a sazonalidade hídrica do solo influencia a germinação e desenvolvimento inicial das plantas, assim como a termoperiodicidade durante a estação seca aumenta o sincronismo e velocidade de germinação. As sementes da espécie estudada formam... / The methods proposed for programs of recovery of degraded areas indicated that the main difficulty is the lack of knowledge regarding adaptive characteristics of each species. In this context, the objective of the study was to analyse the ecophysiological aspects of germination, survival, and initial development of Styrax camporum Pohl. (Styracaceae) under different water and soil conditions in laboratory as well as in natural environments. In the laboratory we studied the influence of temperature, light, and water stress on germination, survival, and initial development of S. camporum; size of seeds; constant temperatures of 10 to 45°C with 5 °C intervals; different light conditions; water stress (at three temperatures, 20, 25, and 30°C); effect of light conditions, substrate, and water content on the initial development. In the field we evaluated the emergence; simulation of a seed bank; survival and development of seedlings planted over a range of light and humidity conditions. The optimal temperature range for seed germination was between 25 and 30°C. The seeds of the species were light insensitive, although under low V:VE ratio, the percentage of germination decreased. The heterogeneity of seed size did not result in differences in the final percentage of seed germination. The S. camporum seeds showed significant decrease in percentage of germination under conditions of low water potential. The results indicate that the seasonality of the water in the soil influences the germination and initial development of the plants, and the thermo-periodicity during the dry season increases the synchronism and germination rate. The seeds of S. camporum form the temporary seed bank. The germination and development of the seedlings of the species in the field are synchronized with the periods in which light, temperature, and water conditions of the soil are suitable. The seedlings... (Complete abstract click electronic access below)

Orientador: Massanori Takaki / Banca: Victor José Mendes Cardoso / Banca: Gustavo Habermann / Banca: José Marcos Barbosa / Banca: José Eduardo Zaia / Resumo: As metodologias propostas nos programas de recuperação de áreas degradadas têm demonstrado que uma das grandes dificuldades encontradas na recomposição de determinadas formações vegetais, é a falta de conhecimento das características adaptativas de cada espécie. Neste contexto, o objetivo do estudo foi conhecer os aspectos ecofisiológicos da germinação, sobrevivência e desenvolvimento inicial de Styrax camporum Pohl. (Styracaceae) sob diferentes condições hídricas e de solo, em condições controladas e no ambiente natural. Para tanto, foram avaliados em laboratório: influência do estresse hídrico, temperatura e luz sobre a germinação, sobrevivência e desenvolvimento inicial de S. camporum; tamanho das sementes; temperaturas constantes de 10 a 45 °C com intervalo de 5 °C; diferentes condições de luz; estresse hídrico (variações do potencial de água em três temperaturas a 20, 25 e 30°C); efeito da condição de luz, substrato e conteúdo de água no desenvolvimento inicial. Em campo, foram avaliadas: emergência; simulação de um banco de sementes; sobrevivência e desenvolvimento de mudas plantadas sob um gradiente de luz e umidade. A faixa ótima de temperatura para germinação de sementes foi de 25 a 30°C, sobre o substrato vermiculita. As sementes da espécie foram insensíveis a luz branca embora sob baixa razão V/VE a porcentagem de germinação foi menor. A heterogeneidade de tamanho das sementes não resultou em diferenças na porcentagem final de germinação As sementes de S. camporum apresentaram redução significativa da porcentagem de germinação sob baixo potencial de água. Os resultados indicam que a sazonalidade hídrica do solo influencia a germinação e desenvolvimento inicial das plantas, assim como a termoperiodicidade durante a estação seca aumenta o sincronismo e velocidade de germinação. As sementes da espécie estudada formam... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The methods proposed for programs of recovery of degraded areas indicated that the main difficulty is the lack of knowledge regarding adaptive characteristics of each species. In this context, the objective of the study was to analyse the ecophysiological aspects of germination, survival, and initial development of Styrax camporum Pohl. (Styracaceae) under different water and soil conditions in laboratory as well as in natural environments. In the laboratory we studied the influence of temperature, light, and water stress on germination, survival, and initial development of S. camporum; size of seeds; constant temperatures of 10 to 45°C with 5 °C intervals; different light conditions; water stress (at three temperatures, 20, 25, and 30°C); effect of light conditions, substrate, and water content on the initial development. In the field we evaluated the emergence; simulation of a seed bank; survival and development of seedlings planted over a range of light and humidity conditions. The optimal temperature range for seed germination was between 25 and 30°C. The seeds of the species were light insensitive, although under low V:VE ratio, the percentage of germination decreased. The heterogeneity of seed size did not result in differences in the final percentage of seed germination. The S. camporum seeds showed significant decrease in percentage of germination under conditions of low water potential. The results indicate that the seasonality of the water in the soil influences the germination and initial development of the plants, and the thermo-periodicity during the dry season increases the synchronism and germination rate. The seeds of S. camporum form the temporary seed bank. The germination and development of the seedlings of the species in the field are synchronized with the periods in which light, temperature, and water conditions of the soil are suitable. The seedlings... (Complete abstract click electronic access below) / Doutor

O presente trabalho foi realizado visando estabelecer metodologia para o teste de germinação e verificar a possibilidade de uso do teste de raios-X para avaliar a qualidade de sementes de aroeira-branca. Foram utilizados quatro lotes de sementes colhidas em áreas da região sul de Minas Gerais, no ano de 2001. As condições de execução do teste de germinação foram determinadas com base nas percentagem e velocidade de germinação das sementes sob nove faixas de temperatura em um gradiente linear entre 15 e 35 °C e sobre os substratos papel mata-borrão, areia e vermiculita. Para o teste de raios-X, as sementes foram radiografadas e classificadas em função do estádio de desenvolvimento e da morfologia, normal e anormal, dos embriões; após o teste de germinação, procedeu-se a comparação da anatomia das sementes com as respectivas plântulas/sementes resultantes. Os resultados permitiram concluir que: (1) o teste de germinação deve ser conduzido a 27 °C, sobre substrato vermiculita e as contagens efetuadas aos 20 e 45 dias após sua instalação; (2) o teste de raios-X é eficiente na detecção de danos e anormalidades nos embriões prejudiciais à germinação. / The present work was carried out with the objective to establish a methodology for the germination test and to verify the possibility to use the X-rays in the evaluation of 'aroeira-branca' seed quality. Four seed lots collected in different places in the south region of the State of Minas Gerais in 2001 were used. The conditions for performing the germination test were determinated basing on the percentage and on the rate of seed germination under nine ranges of temperature in a linear gradient between 15 and 35°C and on substrates of blotters, sand and vermiculite. For the X-ray test, radiography of seeds were made as well as classification in relation to stage of development and morphology, normal and abnormal, of embryo; the germination test was run aiming to detect possible relationship between seedlings/seeds and the respective anatomy as revealed by radiographic pictures. It was concluded that the germination test for 'aroeira-branca' seeds may be run at 27 °C on vermiculite substrate; records have to be made on twenty and forty-five days after the begining of the test. The X-ray test was seen to be able to detect successfully damages and abnormalities in embryos of 'aroeira-branca' seeds.

A pesquisa teve como objetivo estudar procedimentos para a condução dos testes de deterioração controlada, envelhecimento acelerado, condutividade elétrica e lixiviação de potássio, procurando-se verificar sua eficiência para identificação de diferentes níveis de vigor de lotes de sementes de melão (Cucumis melo L.). Para tanto, o estudo foi conduzido em duas etapas, utilizando-se cinco lotes de sementes dos híbridos AF-646 e AF-682. Na primeira foram realizados os testes de germinação, primeira contagem de germinação, Método Agroflora, emergência de plântulas em casa de vegetação e estudos específicos para os testes de deterioração controlada (graus de umidade de 18%, 21% e 24%, a 45ºC, durante 24 e 48 horas), de envelhecimento acelerado, com e sem solução salina (períodos 48, 72 e 96 horas, a 38ºC ou 41ºC), de condutividade elétrica (temperaturas de 20ºC, 25ºC e 30ºC, volumes de 50 e 75mL de água, 25 e 50 sementes e períodos de 1, 2, 4, 8, 12, 16, 20 e 24 horas) e de lixiviação de potássio (25 e 50 sementes, 50 e 75mL de água, a 25ºC e 30ºC, durante 30, 60, e 90 minutos, 2h, 2h e 30 minutos, 3, 4 e 5 horas). Os procedimentos considerados mais promissores para cada teste, nesta primeira fase, foram comparados na segunda etapa, que também incluiu os testes de germinação, primeira contagem de germinação, Método Agroflora e emergência de plântulas em casa de vegetação. Diante dos resultados obtidos, concluiu-se que os testes de deterioração controlada (24%/45ºC/24h) e de envelhecimento acelerado (procedimento tradicional e com solução salina), utilizando a combinação 41ºC/72h, apresentam sensibilidade suficiente para avaliação do potencial fisiológico de sementes de melão. O teste de condutividade elétrica não constitui em opção eficiente para avaliação do vigor das sementes, enquanto o teste de lixiviação de potássio necessita de estudos adicionais para adequar sua metodologia e viabilizar a sua utilização para sementes de melão, considerando-se, inclusive, os prováveis efeitos do genótipo. / This research was conducted to study and select procedures for the controlled deterioration, accelerate aging, electrical conductivity and potassium lixiviation tests, to verify their sensitivity to identify different vigor levels of melon (Cucumis melo L.) seed lots. Five seed lots each from the hybrids AF-646 and AF-682 were used. In the first experimental stage, the following tests were performed: germination, germination first count, Agroflora Method and seedling emergence. Specific studies were also conducted to the following tests: controlled deterioration (seed moisture content of 18%, 21% and 24%, at 45ºC, for 24 and 48 hours), traditional accelerated aging, saturated salt accelerated aging (for 48, 72 and 96 hours, at 38 o C or 41 o C), electrical conductivity (25 or 50 seeds imbibed in 50mL or 75mL water, 20 o C, 25 o C and 30 o C, for 1, 2, 4, 8, 12, 16 and 20 hours) and potassium leachate (25 or 50 seeds, imbibed in 50mL and 75mL, at 25 o C and 30 o C, for 30, 60, 90, 120, 150, 180, 240 and 300 minutes). The procedures considered the most promising for each test in the first stage were compared, in the second stage. The later stage also included germination, germination first count, Agroflora Method and seedling emergence tests. From the results, it was concluded that controlled deterioration (24%/45 o C/24h) and accelerate aging (traditional procedure and salt saturated) tests, using the 41 o C/72h combination, showed to be sufficiently sensitive for the evaluation of the physiological potential of melon seeds. The electrical conductivity test does not constitute an efficient option for the vigor evaluation, while the potassium lixiviation test needs further studies in order to adjust its methodology and enable its use for melon seeds, also considering the probable genotype effects.