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Coffee seeds are classified as intermediate because they have low tolerance to desiccation and low longevity. Consequently, moisture control and storage conditions are important factors in maintaining the physiological quality of these seeds. Thus, the objective in this work was to evaluate the water content effect on coffee seed longevity. Seeds of five Coffea arabica cultivars from the 2016/2017 crop were used. Part of the harvested seeds was dried in the shade until reach 12% moisture and the other part did not go through drying process, remaining with 40% water content. The seeds were stored in a cold chamber at 10 oC for a period of nine months, and the physiological quality was evaluated every three months by germination, root protrusion, seedlings with expanded cotyledonary leaves, seedling dry mass and enzymatic analysis of catalase enzymes and superoxide dismutase. Regardless of the cultivar, wet seeds coffee storage provides better maintenance of physiological quality for up to nine months. Seedling vigor is reduced throughout the storage period, regardless of seed water content. Made available in DSpace on 2021-06-16T02:20:43Z (GMT). No. of bitstreams: 1 Penido-et-al-Cold-coffee-seeds-storage-with-different-water-content.pdf: 1707728 bytes, checksum: e02efe7c1b6d1bcd01015c9c6a91f6d6 (MD5) Previous issue date: 2021

Temperature is one of the climatic elements that affect most the germination process and seedling development. Thus, the objective of this study was to evaluate the germination and seedling development of cowpea cultivars under increasing temperature. The seeds of the cultivars Acauã, Carijó, Guariba, Gurguéia, Itaim, Juruá, Pajeú, Potengi, Pujante, Rouxinol, Tapahium, and Tumucumaque were kept in germination chamber at temperatures of 20, 25, 30, 35 and 40°C, with photoperiod of 12 h. Cowpea seeds have optimal germination performance and seedling development at temperatures in the range of 30.49 - 35.48°C. The cultivars presented germination percentage above 91% under 40°C, however, the seedling were abnormal. The temperature of 20°C provided germination above 96%, but with a longer period to germinate. The temperature range between 30 - 35°C favored the germination speed index, average time, and seed germination speed, with optimum temperatures varying between the cultivars. The highest rate of normal seedlings was observed at temperatures between 25 and 35°C. Made available in DSpace on 2020-11-10T09:17:00Z (GMT). No. of bitstreams: 1 Optimal-temperature-for-germination-and-seedling-development-of-cowpea-2020.pdf: 397715 bytes, checksum: 39efceef9b2662a9dadff7b62f5e9994 (MD5) Previous issue date: 2020

Handroanthus spongiosus (Rizzini) S. Grose is an endangered tree species. However, its seed quality, storage, and conservation strategies are issues still unexplored. This study aimed to evaluate the physiological quality of H. spongiosus seeds subjected to different storage times, packaging, and environments for their conservation. A completely randomized experimental design was used, in a double factorial arrangement with an additional treatment (recently-harvested seeds), consisted of five storage times (up to 24 months) and six storage conditions, combining packaging types (permeable and impermeable) and environments (room, cold chamber, freezer, and liquid nitrogen conditions). Seed germination percentage and normal seedling percentage, shoot length, root length, and root to shoot dry weight ratio were evaluated. The seed germination and normal seedling percentages of H. spongiosus seeds conserved under room conditions decreased over the storage time. Normal seedling percentages decreased from the 12th month of storage onwards. Low and ultralow temperatures are recommended for short and medium-term conservation of H. spongiosus seeds, since they did not affect the growth of seedlings. Resumo: Handroanthus spongiosus (Rizzini) S. Grose é uma espécie arbórea ameaçada. No entanto, a qualidade de suas sementes, o armazenamento e as estratégias de conservação ainda são questões inexploradas. O objetivo deste trabalho foi avaliar a resposta temporal a diferentes embalagens e ambientes de armazenamento na conservação da qualidade fisiológica das sementes de H. spongiosus. O delineamento experimental foi inteiramente casualizado em esquema fatorial duplo com tratamento adicional (sementes recém-colhidas), considerando cinco períodos de armazenamento (até 24 meses) e seis condições de armazenamento, combinando embalagens (permeável ou impermeável) e ambientes (laboratório, câmara fria, freezer e nitrogênio líquido). Germinação, plântulas normais, comprimento da parte aérea e raiz e relação entre a massa seca de raiz e parte aérea foram avaliadas. As sementes de H. spongiosus mantidas em ambiente de laboratório apresentaram decréscimo na porcentagem de germinação e de plântulas normais ao longo do armazenamento. A porcentagem de plântulas normais diminuiu apenas a partir de 12 meses de armazenamento. Temperaturas baixas e ultrabaixas podem ser indicadas para a conservação da qualidade das sementes em armazenamento a curto e médio prazo, uma vez que o crescimento de plântulas não foi afetado.

Fundação de Amparo a Pesquisa do Estado de Minas Gerais CHAPTER I: Aiming to evaluate factors for application in the development of high quality rootstock, two experiments were conducted in protected environment (glasshouse). Factors such as either the presence or absence of the endocarp on the seed, sources of substrate and different concentrations of poultry litter present in the substrate were evaluated as to their influence on the quality and development of the rootstocks. Substrates of common accessible and utilization among the farmers, such as commercial substrate and poultry litter, were used. The works were conducted at the UFU Fruit culture Sector in Uberlândia/MG. In the first experiment, substrates were evaluated (commercial substrate, soil and soil with addition of 25 % of poultry litter vv-1) and their influence on the development of rootstocks with the utilization of seeds either in the presence or absence of the endocarp. Through the results obtained, it was also found that the process of removal of the seed endocarp favored the development of rootstocks, which occurred in a faster way, helping for them to reach the grafting point earlier than the others. However, from among the substrates used, there were no significant differences among them. As to the substrates, there were no significant differences among them, it follows thus, in a general manner, that there was no direct influence of them upon the development of the rootstocks. CHAPTER II: With the objective of evaluating the development as well as the quality of rootstocks of mango tree, cultivar Coquinho, produced on different sources of substrates in the combination with the seed either in the presence or absence of the endocarp, this work was conducted. The experimental design utilized was with randomized blocks in split plots in time with six treatments and six replications each. In each experimental unit were assessed five containers, each containing a rootstock. The treatments were constituted by the factors presence or absence of the endocarp on the seed in combination with the source of substrate used (soil, soil with the addition of poultry litter at 25 % and commercial substrate). The following characteristics were evaluated: height, stem diameter at stem base height and number of leaves. The evaluations were performed at 60, 75, 90, 105 and 120 days after sowing (DAS), afterwards at the completion of the field measurements, the shoots of the rootstocks were collected and the weighing for obtaining the fresh mass (MF) was proceeded and next the drying of the samples in oven at 65 °C for determination of the dry matter (DM). In relation to the results obtained, it was found that there was no significant difference among the substrates used. Regarding the seeds, there was difference in relation to the removal of the endocarp which was significantly superior and contributed by promoting the growth of the rootstocks in a general manner. CHAPTER III: This study aimed to determine the optimal concentration of poultry litter in addition to soil for production of rootstocks mango Coquinho. The experimental design was randomized blocks in split plot design with six treatments and five replications with one plant per container. The treatments consisted of the addition of chicken manure to soil concentrations of addition of poultry litter in a 5:1 ratio , respectively ( 20 % of poultry litter), addition of chicken manure in the ratio of 3:2 (40 % broiler litter) and soil without addition of poultry litter . The soil used was from subsurface horizons. The substrates were combined with Coquinho mango seeds to grow in the presence and absence of the same core material. Height, stem diameter in the lap height and number of leaves expanded to 60, 75, 90, 105 and 120 days after sowing: the characteristics were evaluated. After the last evaluation at 120 DAS proceeded to shoot harvesting of rootstocks for weighing of fresh mass (FM) and subsequently drying the samples in an oven at 65 °C for weighing the dry matter (DM). The originating rootstock seeds in the absence of endocarp showed faster development compared with those that were seeded endocarp. No significant difference between concentrations of poultry litter. CAPITULO I: Objetivando-se avaliar fatores para aplicação no desenvolvimento de porta-enxertos de qualidade, foram conduzidos, dois experimentos em ambiente protegido (estufa). Fatores como; a presença ou ausência do endocarpo na semente, fontes de substratos e concentrações diferentes de cama de frango presentes no substrato foram avaliados quanto a sua influência na qualidade e no desenvolvimento dos porta-enxertos. Substratos de utilização comum e acessíveis entre os produtores, como substrato comercial e cama de frango foram empregados. Os trabalhos foram conduzidos no setor de Fruticultura da UFU, em Uberlândia/MG. No primeiro experimento, foram avaliados substratos (substrato comercial, solo e solo com adição de 25% de cama de frango vv-1) e sua influência no desenvolvimento de porta-enxertos com utilização de sementes na presença ou ausência do endocarpo. Por meio dos resultados obtidos, observou-se que o processo de retirada do endocarpo da semente favorece o desenvolvimento dos porta-enxertos, reduzindo-se assim, o período de permanência dos mesmos no viveiro, observando-se também que a germinação foi precoce promovendo assim, o desenvolvimento dos porta-enxertos nessa condição da semente. Entretanto, dentre os substratos empregados não houve diferença significativa. No segundo experimento foram avaliadas concentrações de cama de frango em adição ao substrato, nas proporções de 0, 20 e 40% vv-1 e sua interação com a semente na presença ou ausência do endocarpo. Por meio dos resultados obtidos, também se observou que o processo de retirada do endocarpo da semente favoreceu o desenvolvimento dos porta-enxertos, que ocorreu de maneira mais rápida auxiliando para que atingissem o ponto de enxertia mais precocemente que os demais. Quanto aos substratos não houve diferença significativa entre os mesmos, conclui-se assim, de uma maneira geral, que não houve influência direta dos mesmos no desenvolvimento dos porta-enxertos. CAPITULO II: Com o objetivo de avaliar o desenvolvimento, bem como a qualidade de porta-enxertos de mangueira cultivar Coquinho, produzidos em diferentes fontes de substratos na combinação com a semente na presença ou ausência do endocarpo, procedeu-se esse trabalho. O delineamento utilizado foi com blocos casualizados (DBC), em parcelas subdivididas no tempo, com seis tratamentos e seis repetições cada. Em cada unidade experimental foram avaliados cinco recipientes, cada um contendo um porta-enxerto cada. Os tratamentos foram constituídos pelos fatores presença ou ausência do endocarpo na semente em combinação com a fonte de substrato empregada (solo, solo com adição de cama de frango a 25% e substrato comercial). Foram avaliadas as seguintes características: altura, diâmetro do caule na altura do colo e número de folhas. As avaliações foram realizadas aos 60, 75, 90, 105 e 120 dias após a semeadura (DAS), posteriormente ao término das mensurações de campo, a parte aérea dos porta-enxertos foram coletadas e procedeu-se a pesagem para obtenção da massa fresca (MF) e em seguida foi realizada a secagem das amostras em estufa a 65 °C para determinação da massa seca (MS). Em relação aos resultados obtidos, verificou-se que não houve diferença significativa entre os substratos utilizados. Quanto às sementes, houve diferença em relação à retirada do endocarpo que foi significativamente superior e contribuiu promovendo o desenvolvimento geral dos porta-enxertos. CAPITULO III: Objetivou-se determinar a concentração ideal de cama de frango na adição ao solo, para produção de porta-enxertos de mangueira Coquinho. O delineamento experimental foi de blocos casualizados em parcelas subdivididas no tempo, com seis tratamentos e cinco repetições, com uma planta por recipiente. Os tratamentos consistiram na adição de cama de frango ao solo nas concentrações de adição de cama de frango na proporção de 5:1 (20% de cama de frango), adição de cama de frango na proporção de 3:2 (40% de cama de frango) e solo sem adição de cama de frango. O solo empregado foi proveniente de horizontes em subsuperfície. Os substratos foram combinados com sementes de manga cultivar Coquinho em presença ou ausência do endocarpo na mesma. Foram avaliadas as características: altura, diâmetro do caule na altura do colo e número de folhas expandidas aos 60, 75, 90, 105 e 120 dias após a semeadura. Após a última avaliação aos 120 DAS procedeu-se a coleta da parte aérea dos porta-enxertos para pesagem da massa fresca (MF) e posteriormente à secagem das amostras em estufa a 65 °C para pesagem da massa seca (MS). Os porta-enxertos originados de sementes na ausência do endocarpo evidenciaram desenvolvimento mais rápido em relação àquelas que foram semeadas com o endocarpo. Não houve diferença significativa entre as concentrações de cama de frango. Mestre em Agronomia

Seasonally tropical dry forests are among the most threatened environments by climate change. However, these forests, which are at risk of desertification, are still poorly studied and conserved. Seeds of several species endemic to the Caatinga, a Brazilian dry forest, are also understudied, mainly regarding their ability to cope with a hotter and drier climate predicted for the future. For the first time in seeds of Cenostigma microphyllum (Leguminosae), we aimed to study the presence of physical dormancy, temperature and salt tolerance to ascertain the effects of current and future climate on seed germination. Intact and scarified seeds were investigated by incubating at constant temperatures (15 to 40°C) or in NaCl solutions (?0.2 to ?1.0 MPa) at 25 and 30°C. Thermal and osmotic thresholds, as well as thermal time and hydrotime constants, were calculated using linear regressions between the germination conditions and germination rate. To predict germination in the future, a heat sum model based on thermal time and hydrotime was applied to current and future climate scenarios. Seeds of C. microphyllum were permeable to water and did not have physical dormancy. The results indicated that increases in temperature are unlikely to affect germination, despite greater sensitivity to salinity presented at higher temperatures. In a future climate, the reduction in the number of weeks with at least 15 mm rainfall will affect the germination timing for the seeds. Thus, we can conclude that under the most pessimistic climate scenario predicted for the future, the seed germination of C. microphyllum may be restricted, likely leading to low seedling recruitment and establishment. Made available in DSpace on 2020-02-10T18:09:11Z (GMT). No. of bitstreams: 1 Influenceofcurrentandfutureclimate2019.pdf: 561195 bytes, checksum: 4f0fe59113afd021b7841cf4421f61a7 (MD5) Previous issue date: 2019

This study evaluates the effects of hydration and dehydration cycles (HD cycles) on seed germination of four Caatinga tree species (Anadenanthera colubrina var. cebil, Enterolobium contortisiliquum, Pityrocarpa moniliformis and Pterogyne nitens) subjected to different temperatures and determine the thermal upper and lower limits of germination. For this, seeds were subjected to 0, 1, 2 and 3 HD cycles and set to germinate at temperatures of 5, 10, 15, 25, 35, 40 and 45 °C. Germinability and t50 were calculated and the differences of these parameters were compared by two-way ANOVA. In addition, germination rate (GR = 1/t50), as well as ceiling (Tc), optimum (To) and base (Tb) temperatures were calculated to estimate the limits below or above which the seeds fail to germinate. We observed that the more HD cycles, the better the seed responds, especially at extreme temperatures. Seeds of all studied species showed To between 25 and 35 °C, Tb < 10 °C, and Tc > 40 °C. The slope of regression curves for germination rate showed that submitting seeds to HD cycles expands its thermal tolerance range, revealing that this seed pre-treatment can be efficient for species as it increases their tolerance to thermal stress. Resumo: Este estudo avaliou os efeitos dos ciclos de hidratação e desidratação (ciclos de HD) na germinação de sementes de quatro espécies arbóreas da Caatinga (Anadenanthera colubrina var. cebil, Enterolobium contortisiliquum, Pityrocarpa moniliformis and Pterogyne nitens) submetidas a diferentes temperaturas, determinando os limites térmicos para germinação. As sementes foram submetidas a 0, 1, 2 e 3 ciclos de HD e colocadas para germinar nas temperaturas de 5, 10, 15, 25, 35, 35, 40 e 45 °C. Germinabilidade e t50 foram calculados e as diferenças foram comparadas pela ANOVA Dois Fatores. Além disso, a taxa de germinação (GR = 1/t50), bem como temperaturas teto (Tc), ótima (To) e base (Tb) foram calculadas para estimar os limites abaixo ou acima dos quais as sementes não germinam. Foi observado que quanto mais ciclos de HD, melhor é a resposta da semente, principalmente em temperaturas extremas. Sementes de todas as espécies apresentaram To entre 25 e 35 °C, Tb < 10 °C e Tc > 40 °C. A inclinação das curvas de regressão da taxa de germinação mostrou que os ciclos de HD expandem faixa de tolerância térmica das sementes, revelando que esse pré-tratamento pode ser eficiente para as espécies, aumentando sua tolerância ao estresse térmico.

Eucalyptus cloeziana is one of the highest-density wood species offering significant added value, frequently used in the construction and furniture industries. Despite its suitability, it may be overlooked on account of its propagation difficulties due either to its low rooting cutting capacity or to its seeds having a low germination rate perhaps attributable to the high proportion of indistinguishable impurities within the seed lots. This study aimed to develop an efficient technique for Eucalyptus cloeziana seed processing to increase the physical purity and, consequently, the physiological quality of the seed lot. Three seed lots, separated by size in sieves with 1.18, 1.00, and 0.84 mm square openings, were used. X-ray analyses were carried out, the number of normal seedlings and germination rate identified and the percentage and speed of seedling emergence under greenhouse conditions ascertained. The greenhouse evaluation showed that the seed retained in the 1.18 mm sieve presented viability and vigor twice that of the control. Therefore, the processing technique by size classification is efficient in terms of improving the physical and physiological performance of Eucalyptus cloeziana seed lots. Made available in DSpace on 2021-07-29T18:00:22Z (GMT). No. of bitstreams: 1 Elisa-Beneficiamento-E.-cloeziana.pdf: 2422781 bytes, checksum: 48c4757f17c7f08da85b005b2756a8ff (MD5) Previous issue date: 2021

Knowledge about seed storage behavior is important to preserve plant species. Clitoria fairchildiana R.A.Howard is an endemic species with medicinal properties, it is used in the recovery of degraded land. The objective of this study is to evaluate the effect of drying on the physiological quality of C. fairchildiana seeds. Seeds were oven dried along with silica gel for 18 days and in intervals of 2 or 3 days, samples were removed to assess the seed moisture content. This was done in an oven at 105±3 oC for 24h, using four replicates with 10 seeds each. After undergoing the above-mentioned treatment, a sample of seeds was stored in the freezer (-18 ºC) for 3 months. Sowing was carried out in plastic trays in a sand and sawdust mixture (1:1), previously sterilized in hot water (100 oC) for two hours. Seeds were left to germinate in a laboratory with no temperature and relative humidity control. Germination tests were performed over 14 days with daily counts of the number of emerged seedlings. The percentage of seed germination, abnormal seedlings and dead seeds were obtained 14 days after sowing. The experimental design was completely randomized with four replications of 25 seeds. The reduction of seed moisture content from 18.5% to 5.6% affected physiological seed quality causing a reduction in the germination percentage and an increase in dead seeds and abnormal seedling percentage. C. fairchildiana seeds are classified as intermediate and they can be desiccated up to 8.6% with no reduction in physiology quality. El conocimiento sobre el almacenamiento de semillas es importante para la preservación de especies vegetales. La Clitoria fairchildiana R.A.Howard es una especie endémica con propriedades medicinales utilizada en la reconstitución de áreas degradadas. El objetivo de este estudio fue analizar el efecto del secado en la calidad fisiológica de las semillas de esta especie. Las semillas se secaron en gel de sílice durante 18 días y, en intervalos de 2 o 3 días, se fueron retirando muestras para determinar el grado de humedad. Este se obtuvo en invernadero a 105±3 °C durante 24h, con 4 repeticiones de 10 semillas. Después de obtener el último grado de humedad, se almacenó una muestra de las semillas en frigorífico (-18ºC) durante 90 días. La siembra se hizo en macetas que contenían substrato de arena y serrín, en la proporción de 1:1, previamente hervido en agua durante dos horas. Las macetas permanecieron en laboratorio desprovisto de controles de temperatura y de humedad relativa del aire. La prueba de germinación se desarrolló durante 14 días con cuenta diaria de las plántulas emergidas y, a finales de esta, se determinaron los porcentajes de germinación, las semillas muertas y las plántulas anormales. El delineamento fue completamente casualizado con cuatro repeticiones de 25 semillas por tratamiento. La reducción del grado de humedad del 18,5% a 5,6% afectó a la calidad fisiológica de las semillas acarreando una reducción en la tasa de germinación y un aumento en el porcentaje de semillas muertas y de plántulas anormales. Las semillas de C. fairchildiana se clasifican como intermedias en el almacenamiento y pueden secarse hasta un 8,6% sin alteración en la calidad fisiológica. O conhecimento acerca o armazenamento de sementes é importante para a preservação de espécies vegetais. A Clitoria fairchildiana R.A.Howard é uma espécie endêmica com propriedades medicinais utilizada na reconstituição de áreas degradadas. O objetivo deste estudo foi analisar o efeito da secagem na qualidade fisiológica de sementes dessa espécie. As sementes foram secadas em sílica gel por 18 dias em intervalos de 2 ou 3 dias amostras foram retiradas para determinação do grau de umidade. Este foi obtido em estufa a 105±3oC por 24h, com 4 repetições de 10 sementes. Após obter o último grau de umidade uma amostra das sementes foi armazenada em freezer (-18ºC) por 90 dias. A semeadura foi em vasos contendo substrato de areia e serragem, na proporção de 1:1, previamente cozido em água aquecida por duas horas. Os vasos permaneceram em laboratório desprovido de controles de temperatura e de umidade relativa do ar. O teste de germinação ocorreu durante 14 dias com contagem diária das plântulas emersas e no final desse determinou-se as porcentagens de germinação, sementes mortas e plântulas anormais. O delineamento foi inteiramente casualizado com quatro repetições de 25 sementes por tratamento. A redução do grau de umidade de 18,5% para 5,6% afetou a qualidade fisiológica das sementes acarretando redução na taxa de germinação e aumento na porcentagem de sementes mortas e de plântulas anormais. Sementes de C. fairchildiana são classificadas como intermediária no armazenamento e podem ser secadas até 8,6% sem alteração na qualidade fisiológica.

Hog plum tree seeds (Spondias mombin L.) have a complex dormancy mechanism, which causes slow germination and great unevenness. At present, there are no efficient methods to promote seed germination. The objective of the study was to evaluate the effect of storage on overcoming seed dormancy of this Anacardiaceae. Diaspores of two hog plum trees were used, identified as Mother plant 1 and Mother plant 2, established in Tomé-Açu city, PA. Initially, it was investigated whether the structures surrounding the seeds (internal mesocarp and endocarp) prevent water absorption. For this, the diaspores of the two mother plants were sown between blotting paper, with an adequate level of water and, periodically, in the total of 144 hours, the water content of the seeds was computed. The storage studies involved two experiments. In the first, diaspores from both mother plants with a water content of around 5.0% were stored in impermeable packages, for one year, under the following conditions: natural environment of Belém, PA (average temperature of 26.8 °C) and at temperatures of 6 ± 1 ° C and minus 18 ± 2 °. The germinative response of the stored diaspores was compared with those of non-stored diaspores. Prior to storage, selection was made on the diaspores, discarding the small ones. In the second experiment, the germinative response of the diaspores of the two mother plants, stored for zero, one, two, three, four, five and six months, under natural environment conditions of Belém, PA, was evaluated. It was observed that the structures that cover the seeds do not offer restrictions to the water absorption, thus discarding the hypothesis of physical dormancy, without, however, excluding the possibility of mechanical dormancy. The storage of diaspores for one year, regardless of the storage condition, did not affect the germination power of the seeds. On the other hand, responses of great magnitude, in terms of reducing the time required for germination, were obtained when the diaspores were stored under natural conditions and at minus 18±2 °C, indicating that dormancy is naturally overcome by storage . Overcoming dormancy was a little slower when the diaspores were stored at a temperature of 6±1 °C. It was found that the storage of diaspores in an environment with an average temperature of 26.8 °C for three months provides the overcoming dormancy of most of the seeds. The intensity of dormancy varied within and between mother plants. Resumo As sementes de cajazeira (Spondias mombin L.) apresentam complexo mecanismo de dormência, que condiciona germinação lenta e desuniforme. Presentemente, não existem métodos eficientes para promover a geminação das sementes. O objetivo do trabalho foi avaliar o efeito do armazenamento sobre a superação da dormência de sementes dessa Anacardiaceae. Foram utilizados diásporos de duas cajazeiras, identificadas como Planta matriz 1 e Plant matriz 2, estabelecidas no município de Tomé-Açu-PA. Inicialmente, foi investigado se as estruturas que envolvem as sementes (mesocarpo interno e endocarpo) impedem a absorção de água. Para tanto, diásporos das duas plantas foram semeados entre papel mata-borrão, com nível adequado de água e, periodicamente, no total de 144 horas computou-se o teor de água das sementes. Os estudos de armazenamento envolveram dois experimentos. No primeiro, diásporos de ambas as matrizes, com teor de água em torno de 5,0%, foram armazenados em embalagens impermeáveis, durante um ano, nas seguintes condições: ambiente natural de Belém-PA (temperatura média de 26,8°C) e nas temperaturas de 6±1°C e 18±2°C negativos. A resposta germinativa dos diásporos armazenados foi comparada com as de diásporos não armazenados. Antecedendo ao armazenamento, efetuou-se seleção nos diásporos descartando-se os de tamanho diminuto. No segundo experimento, considerou-se a resposta germinativa dos diásporos das duas plantas matrizes, armazenados nas condições de ambiente natural de Belém-PA, durante seis meses, e avaliados mensalmente. Observou-se que as estruturas que recobrem as sementes não oferecem restrições à absorção de água, descartando, portanto, a hipótese de dormência física, sem, no entanto, excluir a possibilidade de dormência mecânica. O armazenamento dos diásporos, durante um ano, independentemente da condição de armazenamento, não afetou o poder germinativo das sementes. Por outro lado, respostas de grande magnitude, em termos de redução do tempo requerido para germinação, foram obtidas quando os diásporos foram armazenados nas condições de ambiente natural e a 18±2°C negativos, indicando que a dormência é naturalmente superada pelo armazenamento. A superação da dormência foi mais lenta quando os diásporos foram armazenados a 6±1°C. Constatou-se que o armazenamento dos diásporos nas condições de ambiente natural de Belém, durante três meses, proporciona a superação da dormência da maior parte das sementes. A intensidade da dormência variou dentro e entre plantas matrizes.

A few years ago, concerns about the need to recover degraded areas and to restructure the landscape began. One of the difficulties to produce native seedlings, among several factors, is the dormancy of the seeds of some species because even in favorable environments the seeds do not germinate. The objective of this study was to evaluate the influence of different methods of overcoming dormancy in the emergence of two species of the Fabaceae family, native to the Cerrado of the northeast of Mato Grosso do Sul, Brazil. Seven treatments were used for both species, where there was a combination of scarification with immersion in water. The dormancy break methods applied to interfere with the germination percentage and the emergence velocity index for both species. To Dimorphandra mollis, the best treatment is a scarification opposite to the hilum followed by immersion in water for 9 hours. To Hymenaea stigonocarpa, the use of at least two scarifications followed by immersion in water favors the percentage of germinated seeds while, two lateral scarifications to the hilum, combined with immersion in water, favors the velocity of the emergence of these seeds. Hace unos años, comenzaron las preocupaciones sobre la necesidad de recuperar áreas degradadas y reestructurar el paisaje. Una de las dificultades para producir plántulas nativas, entre varios factores, es la latencia de las semillas de algunas especies porque incluso en ambientes favorables las semillas no germinan. El objetivo de este estudio fue evaluar la influencia de diferentes métodos para superar la latencia en la aparición de dos especies de la familia Fabaceae, nativas del Cerrado del noreste de Mato Grosso do Sul, Brasil. Se utilizaron siete tratamientos para ambas especies, donde hubo una combinación de escarificación con inmersión en agua. Los métodos de interrupción de la latencia aplicados interfieren con el porcentaje de germinación y el índice de velocidad de emergencia para ambas especies. Para Dimorphandra mollis, el mejor tratamiento es una escarificación opuesta al hilio seguida de inmersión en agua durante 9 horas. Para Hymenaea stigonocarpa, el uso de al menos dos escarificaciones seguidas de inmersión en agua favorece el porcentaje de semillas germinadas, mientras que dos escarificaciones laterales al hilio, combinadas con la inmersión en agua, favorecen la velocidad de aparición de estas semillas. Alguns anos atrás começaram as preocupações com a necessidade de recuperar áreas degradadas e reestruturar a paisagem. Uma das dificuldades para produzir mudas nativas, entre vários fatores, é a dormência das sementes de algumas espécies, porque mesmo em ambientes favoráveis as sementes não germinam. O objetivo deste estudo foi avaliar a influência de diferentes métodos de superação da dormência no surgimento de duas espécies da família Fabaceae, nativas do Cerrado do nordeste do Mato Grosso do Sul, Brasil. Sete tratamentos foram utilizados para ambas as espécies, onde houve uma combinação de escarificação e imersão em água. Os métodos de quebra de dormência aplicados para interferir na porcentagem de germinação e no índice de velocidade de emergência para ambas as espécies. Para Dimorphandra mollis, o melhor tratamento é uma escarificação oposta ao hilo seguida de imersão em água por 9 horas. Para Hymenaea stigonocarpa, o uso de pelo menos duas escarificações seguidas de imersão em água favorece o percentual de sementes germinadas, enquanto duas escarificações laterais ao hilo, combinadas à imersão em água, favorecem a velocidade de emergência dessas sementes.

Selecting genotypes that combine high productivity with high seed quality is a challenge. The exploration of intracultivar genetic variation is an alternative to significantly increase the annual genetic gain and maximize the selection efficiency for both characteristics. The present study aimed to identify intracultivar variation to improve the seed quality of soybean genotypes derived from the commercial cultivar BRS 284, selected using the HSD (Honeycomb Selection Designs) model. Soybean genotypes selected for two years from two environments with contrasting edaphoclimatic characteristics, according to the principles of the HSD selection model, were cultivated under competition by using the experimental model in randomized blocks with four replicates and evaluated regarding the productivity and physiological quality of seeds. The results showed that genotype 284-3 presented a greater mass of 100 seeds, germination, vigour after accelerated ageing test, seedling emergence and emergence speed index than the other genotypes in both environments, with no significant difference in the standard cultivar regarding seed yield. The HSD method was an efficient selection method to identify intracultivar variation to improve cultivar performance. Selecting genotypes that combine high productivity with high seed quality is a challenge. The exploration of intracultivar genetic variation is an alternative to significantly increase the annual genetic gain and maximize the selection efficiency for both characteristics. The present study aimed to identify intracultivar variation to improve the seed quality of soybean genotypes derived from the commercial cultivar BRS 284, selected using the HSD (Honeycomb Selection Designs) model. Soybean genotypes selected for two years from two environments with contrasting edaphoclimatic characteristics, according to the principles of the HSD selection model, were cultivated under competition by using the experimental model in randomized blocks with four replicates and evaluated regarding the productivity and physiological quality of seeds. The results showed that genotype 284-3 presented a greater mass of 100 seeds, germination, vigour after accelerated ageing test, seedling emergence and emergence speed index than the other genotypes in both environments, with no significant difference in the standard cultivar regarding seed yield. The HSD method was an efficient selection method to identify intracultivar variation to improve cultivar performance.

As análises de sementes devem ser realizadas em condições padronizadas para cada espécie, para que assim os resultados possam ser reprodutíveis em qualquer lugar. Sementes da espécie florestal Toona ciliata var. australis têm sido comercializadas no Brasil apesar de não haver condições padronizadas publicadas para sua análise. O objetivo foi determinar informações básicas sobre temperatura e fotoperíodo para o teste de germinação e tempo de embebição e volume de água para condutividade elétrica. Para o teste de germinação as sementes foram incubadas a 15, 20, 25 e 30 °C com 0, 12 e 16 h de luz. A condutividade elétrica foi avaliada até 108 h após imersão das sementes em 50 e 100 mL de água deionizada. As condições de 25 °C e 16 h de luz proporcionaram maior quantidade de plântulas normais. A 15 °C todas as sementes permaneceram duras independente do fotoperíodo utilizado, entretanto, isso se tornou ausente quando foi adicionado luz em temperaturas maiores. O teste de condutividade elétrica deve ser realizado com volume de 50 mL e avaliado após 24 h de embebição. Esse teste também mostrou uma correlação forte entre plântulas normais, sendo considerado então um promissor teste para avaliar o vigor dessa espécie. Seed analysis tests should be performed under standard conditions for each species, so that the results can be reproducible anywhere. Seeds of the forest species Toona ciliata var. australis have been commercialized in Brazil despite no standard conditions for their analysis have been published. The objective was to determine basic information about temperature and photoperiod for the germination test and the imbibition time and volume of water for electrical conductivity. In the germination test the seeds were incubated at 15, 20, 25 and 30 °C with 0, 12 and 16 h of light. The electrical conductivity was evaluated up to 108 h after immersion of the seeds in 50 and 100 mL of deionized water. The conditions of 25 °C and 16 h of light provided higher amount of normal seedlings. At 15 °C all seeds remained hard regardless the photoperiod used, however, it became absent when light was added at higher temperatures. The electrical conductivity test should be performed with a volume of 50 mL and evaluated after 24 h of imbibition. It also showed a stronger correlation between normal seedlings, being a promising vigor evaluation test for this species.

O objetivo desse trabalho foi avaliar a qualidade fisiológica de sementes de Campomanesia aurea O. Berg armazenadas sob duas temperaturas. Sementes da espécie foram secas e armazenadas a 25 °C e 8 °C por 0, 30, 60, 90 e 150 dias. Observou-se diminuição linear de germinação e do índice de velocidade de germinação, com queda mais acentuada para sementes estocadas a 25 °C. Sementes de C. aurea armazenadas a 8 °Cmantiveram viabilidade de 80% por 150 dias, evidenciando o potencial dessa espécie para a produção de mudas em viveiro de forma programada ao longo deste período. The objective of this work was to evaluate the physiological quality of Campomanesia aurea O. Berg seeds stored under two temperatures. Seeds were dried and stored at 25 °C and 8 °C for 0, 30, 60, 90 and 150 days. We observed a linear decrease in germination and germination speed index, with a steeper drop for seeds stored at 25 °C. C. aurea seeds stored at 8°C maintained viability of 80% for 150 days, evidencing the potential of this species for seedlings production if programmed during this period.

O processo de germinação tem início com a embebição, por ocasião da água disponível, a qual desencadeia uma sequência de mudanças metabólicas que culminam com a protrusão da raiz primária, em sementes viáveis. Pela organização do sistema de membranas celulares, um método que pode indicar o nível de vigor das sementes é a condutividade. Objetivou-se avaliar e modelar o processo de embebição de sementes de grão-de-bico, além de estabelecer metodologia eficiente para volume de água, tempo de embebição e número de sementes no teste de condutividade elétrica. Foram utilizados oito lotes, sendo quatro da cultivar BRS Aleppo e quatro da cultivar Cícero que foram submetidos ao teste de germinação e vigor para caracterização inicial. A condutividade elétrica foi conduzida com subamostras de 50 e 75 sementes utilizando 75 e 100 mL de água deionizada, e avaliou-se os períodos 2, 4, 8, 12, 18, 24 e 30 h, mantidas à temperatura de 25 °C. O experimento de condutividade elétrica foi em delineamento inteiramente casualizado com quatro repetições. Para cinética de embebição foi ajustado o modelo de Peleg. A metodologia mais adequada foi a utilização de 75 sementes, volume de 100 mL de água durante 30 h. O modelo de Peleg foi eficiente na descrição do processo de absorção de água, ainda que haja diferenças no potencial fisiológico dos lotes. Made available in DSpace on 2019-12-30T18:08:59Z (GMT). No. of bitstreams: 1 5601164121PB.pdf: 2206532 bytes, checksum: 4f3a0603c4a2447f61765a0c1330c019 (MD5) Previous issue date: 2019

A demanda por sementes florestais nativas vem crescendo, devido a produção de mudas que visam recuperar áreas abandonadas, degradadas e de reflorestamento, tornando-se imprescindível conhecer o comportamento dessas sementes quanto a tolerância à dessecação e armazenamento, visando sua conservação. O objetivo do trabalho foi classificar as sementes de Manilkara huberi quanto à tolerância à dessecação e ao comportamento no armazenamento. Após o beneficiamento das sementes, foram determinados os teores de água das sementes recém-beneficiadas e submetidas ao processo de secagem, seguidos pelos testes de germinação. De acordo com os resultados, conclui-se que as sementes de M. huberi são classificadas como recalcitrantes, por não tolerarem o processo de secagem e o armazenamento em baixas temperaturas. A espécie M. huberi pertence ao grupo de espécies clímax. Made available in DSpace on 2019-11-13T18:14:39Z (GMT). No. of bitstreams: 1 2949Textodoartigo1320811020190225.pdf: 467118 bytes, checksum: 5eb41cb8e890a2089f5731d7dc044e55 (MD5) Previous issue date: 2019

Peroba rosa (Aspidosperma polyneuron) is a native forest species endangered due to intense predatory exploitation. The objective of this study was to evaluate the association and fungi transmission in peroba rosa seeds from four regions of Paraná. Germination and vigor were evaluated using the paper roll method. Sanitary analysis consisted of the detection of endophytic and epiphytic fungi using potato-dextrose-agar medium and Fusarium selective medium. For transmission, non-disinfested seeds were sown in vermiculite and kept in greenhouse. Germination ranged from 9.3% to 60%. Fusarium sp. and Phomopsis sp. were found as epiphytic and also as endophytic. There was transmission of Fusarium sp. and Phomopsis sp. from seeds to seedlings, causing malformation and necrosis on roots and cotyledons. Made available in DSpace on 2019-06-04T00:32:27Z (GMT). No. of bitstreams: 1 2019AlvaroFloramAssociation.pdf: 840203 bytes, checksum: 0f4dde7e10af2dca8606a97989620c54 (MD5) Previous issue date: 2019

Poincianella pyramidalis (Fabaceae), Schinopsis brasiliensis (Anacardiaceae) and Sideroxylon obtusifolium (Sapotaceae) are native species of the Caatinga vegetation from northeastern Brazil and have both biological importance and potential economic uses. Little is known about the water uptake and degradation of storage proteins during seed germination of these species. The aim of this study was to evaluate the imbibition and quantify the amount of storage proteins during seed germination of P. pyramidalis, S. brasiliensis and S. obtusifolium. Two lots of S. obtusifolium seeds with different vigour were used. Four replicates of 20 seeds of P. pyramidalis, S. brasiliensis and S. obtusifolium, were sown onto gerboxes with blotting paper soaked in distilled water and incubated during 72, 200 and 624 hours. Before and after imbibition seeds were weighed and frozen at until the sequential extraction and analysis of the seed storage proteins. Based on our results, we conclude that seed germination of P. pyramidalis, S. brasiliensis and S. obtusifolium has a well-defined triphasic imbibition. All storage proteins content of P. pyramidalis and S. brasiliensis seeds degraded along with the seed imbibition. Likewise, the content of albumins, globulins and glutelins decreased as S. obtusifolium seeds absorbed water.

Jatropha curcas L. is a plant species with many potential applications, especially medicinal uses (hypoglycemic, anti-inflammatory, haemostatic, healing, anti-tumor). The objective of this study was to test germination in moist paper rolls for whole seeds and in vitro for excised embryonic axes, in an attempt to identify the best method to assess the quality of J. curcas seed germplasm, cryopreserved with different water contents. The experimental sample with a 6.2% moisture content (MC) was divided in subsamples which were hydrated and dehydrated for 0 (control), 4, 8, 11 and 24h. The initial germination percentages were 63% for whole seeds and 81% for excised embryonic axes. After exposure to liquid nitrogen (LN), germination percentages were 48% (whole seeds) and 57% (excised embryonic axes). There was no significant difference between germination percentages in embryonic excised from seeds subjected or not subjected to freezing, with different MC. In contrast, there was a reduction of the whole seed germination percentage when exposed to LN (contrast = 0.17, standard error = 0.04, t = 4.09, p = 0.001) and not for the hydration and dehydration treatments. The methodology based on in vitro cultures of the embryonic axis isolated from seeds stored in LN with distinct MC values was more efficient than the standard germination test to evaluate the viability of J. curcas seeds before and after LN storage. RESUMO Jatropha curcas L., é uma espécie com várias aplicações potenciais, principalmente para usos medicinais (hipoglicemina, anti-inflamatório, homeostático, cicatrizante, antitumoral). O objetivo deste estudo foi testar a germinação em rolo de papel para sementes inteiras e in vitro para eixos embrionários excisados visando identificar o melhor método para avaliar a qualidade de germoplasma semente de J. curcas, criopreservado com diferentes teores de água. A amostra experimental com 6,2% de teor de água foi dividida em subamostras que foram hidratadas e desidratadas por 0 (controle), 4, 8, 11 e 24 h. Os percentuais de germinação inicial foram de 63% para sementes inteiras e de 81% para eixos embrionários excisados. Após exposição ao nitrogênio líquido (NL) os percentuais de germinação foram de 48% (sementes inteiras) e 57% (eixos embrionários). Não houve diferença significativa entre os percentuais de germinação de eixos embrionários excisados de sementes com diferentes umidades e submetidas ou não ao congelamento. Em contraste, houve redução de percentuais de germinação das sementes inteiras expostas ao NL (contraste = 0.17, erro padrão = 0.04, t = 4.09, p = 0.001), mas não aos tratamentos de hidratação e desidratação. A metodologia baseada em cultura de eixos embrionários in vitro isolados de sementes armazenadas em NL, com distintos teores de água foi mais eficiente que a germinação padrão para avaliar a viabilidade de sementes J. curcas antes e após a armazenamento em NL.

The aim of the present study was to establish parameters to evaluate melon seeds vigor by ethanol release test using a modified ethylometer and correlate with physiological seed quality, gene expression and enzyme activities alterations. To perform this trial, six seeds lots of yellow melon were submitted to determinations such as moisture content, germination assay and vigor tests. 25 and 50 seeds soaked with 0.5 mL of distilled water and tested after 1, 2, 3, 4, 5, 6 and 24 h at 40 °C. After 0, 6 and 24 h of imbibition, the high and low vigor lots were evaluated for the following enzyme activity: superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (GPX), ascorbate peroxidase (APX) and alcoholic dehydrogenase (ADH). Accumulation of ADH protein was verified using Western Blotting hybridization technique with the primary Anti-ADH antibody. The release of ethanol in 25 seeds, soaked in 0.5 mL of distilled water for 6 h, proved efficient for vigor evaluation and can be related to other traditionally used tests. Enzyme activity varied according to the vigor of the seed lot. For the protein profile, there was variation in the accumulation of proteins of specific molecular weights throughout the soaking periods. There was also variation in expression according to accumulation of ADH protein. The biochemical and molecular tests corroborate with the establishment of the ethanol test as an additional tool to evaluate seed vigor. Made available in DSpace on 2022-09-14T13:05:51Z (GMT). No. of bitstreams: 1 Gene-expression-biochemical-and-physiological-2020.pdf: 1309518 bytes, checksum: 26abe83a9c161fe02e59d5448cc2b354 (MD5) Previous issue date: 2020

Objetivou-se avaliar os efeitos de ácido giberélico em diferentes concentrações e períodos de imersão enquanto promotores da superação da dormência das sementes de Brachiaria humidicola cv. BRS Tupi de diferentes lotes e tempos de armazenamento antes dos tratamentos. Os quatro experimentos realizados contaram com diferentes lotes de sementes, em esquema fatorial em diferentes períodos de armazenamento após a colheita (6, 7, 8 e 9 meses), em que os tratamentos consistiram na imersão das sementes em soluções com diferentes concentrações de ácido giberélico (0; 50; 150; 300 e 600 mg L-1), por três períodos de exposição (12, 24 e 48 h), em comparação a uma testemunha (sem tratamento) em delineamento inteiramente casualizado. As avaliações efetuadas foram: curva de embebição, germinação, índice de velocidade de germinação, primeira contagem de germinação e viabilidade pelo teste de tetrazólio. As sementes responderam positivamente a todos os tratamentos após oito meses de armazenamento, enquanto as testemunhas continuaram dormentes. Nenhum dos tratamentos proporcionou perda na viabilidade e demonstraram possibilidade de armazenamento. Para os períodos acima de 24 h de embebição há risco de protrusão radicular, podendo acarretar em morte da semente. Made available in DSpace on 2018-12-21T23:35:31Z (GMT). No. of bitstreams: 1 Superacaodadormenciaemsementes.pdf: 516311 bytes, checksum: 2a944650cac59bdb6e6b406e80f61847 (MD5) Previous issue date: 2018-12-19 Título em inglês: Overcoming dormancy in Brachiaria humidicola cv. BRS Tupi by using gibberellic acid.

Drylands are predicted to become more arid and saline due to increasing global temperature and drought. Although species from the Caatinga, a Brazilian tropical dry forest, are tolerant to these conditions, the capacity for germination to withstand extreme soil temperature and water deficit associated with climate change remains to be quantified. We aimed to evaluate how germination will be affected under future climate change scenarios of limited water and increased temperature. Seeds of three species were germinated at different temperatures and osmotic potentials. Thermal time and hydrotime model parameters were established and thresholds for germination calculated. Germination performance in 2055 was predicted, by combining temperature and osmotic/salt stress thresholds, considering soil temperature and moisture following rainfall events. The most pessimistic climate scenario predicts an increase of 3.9 °C in soil temperature and 30% decrease in rainfall. Under this scenario, soil temperature is never lower than the minimum and seldomly higher than maximum temperature thresholds for germination. As long as the soil moisture (0.139 cm3 cm3) requirements are met, germination can be achieved in 1 day. According to the base water potential and soil characteristics, the minimum weekly rainfall for germination is estimated to be 17.5 mm. Currently, the required minimum rainfall occurs in 14 weeks of the year but will be reduced to 4 weeks by 2055. This may not be sufficient for seedling recruitment of some species in the natural environment. Thus, in future climate scenarios, rainfall rather than temperature will be extremely limiting for seed germination. Made available in DSpace on 2020-02-21T18:10:31Z (GMT). No. of bitstreams: 1 Rainfallnotsoiltemperaturewilllimittheseedgerminationofdry2020.pdf: 3202683 bytes, checksum: 1a6594dd57f074a3945a09b035657ac6 (MD5) Previous issue date: 2020

The removal of lint from cotton seeds is mainly carried out through chemical delinting, but it is an expensive procedure and requires high technology. The objective was to evaluate the physiological quality of Gossypium hirsutum L. seeds delinted by flaming using a thermal delinter prototype. Cotton seeds BRS 286 were flamed in nine settings intensities and compared to chemical delinting and seeds with lint. We analyzed the water content, germination, first count, germination speed index (GSI), length and dry mass of roots and shoots. Using a completely randomized design and the means were compared by Scott-Knott test at 5% probability. In evaluating, the germination percentage did not differ between treatments with chemical and thermal low intensity delinting compared to the control. In vigor tests were observed higher mean values of the chemical treatment to the other treatments, except in GSI test and root dry weight when subjected to thermal delinting of low and medium intensity. The delinting made through the prototype enables efficient results, as well as the chemical delinting with sulfuric acid, without affecting germination and vigor when flamed with low and middle intensity, regardless of the number of active burners. Made available in DSpace on 2019-03-15T18:11:16Z (GMT). No. of bitstreams: 1 108.Physiologicalquality.pdf: 319492 bytes, checksum: b7437069eadf7ad5678721743e65c7c9 (MD5) Previous issue date: 2018

Given that watermelon is a crop widespread around the world, there is considerable interest in verifying how its seeds physiologically behave under unfavorable temperature conditions. This study aimed to evaluate the biochemical changes mobilization and reserves degradation, as well as the enzyme activity, during seed germination and initial growth of watermelon seedlings subjected to thermal stress, using temperature, germination percentage, germination rate and relative germination frequency over the incubation time as evaluation parameters. The experimental design was completely randomized, in a 5 x 3 factorial scheme, with five temperatures (17 ºC, 20 ºC, 25 ºC, 30 ºC and 35 ºC) and three cultivars (Charleston Gray, Fairfax and Crimson Sweet), with 4 replicates of 50 seeds. Germination, seedling growth, reserve degradation and stress protection system were evaluated. Thermal stress caused deleterious effects on watermelon seeds with germination capacity at well defined temperature limits, being 25 ºC the ideal temperature, with the highest percentage of normal seedlings. Sub- (17 ºC) and supra-optimal (30 ºC) temperatures presented more than 80 % of abnormal seedlings. The α-amylase enzyme activity is intense only at the beginning of germination. Under thermal stress, the proline contents increase mainly in the cotyledons. RESUMO Considerando-se que a melancia é uma cultura bem difundida no mundo, há grande interesse em verificar como suas sementes se comportam fisiologicamente sob condições de temperatura desfavoráveis. Objetivou-se avaliar as alterações bioquímicas de mobilização e degradação de reservas, bem como a atividade enzimática, durante a germinação de sementes e crescimento inicial de plântulas de melancia submetidas a estresse térmico, utilizando-se temperatura, porcentagem de germinação, taxa de germinação e frequência relativa de germinação ao longo do tempo de incubação como parâmetros de avaliação. O delineamento experimental foi inteiramente casualizado, em esquema fatorial 5 x 3, com cinco temperaturas (17 ºC, 20 ºC, 25 ºC, 30 ºC e 35 ºC) e três cultivares (Charleston Gray, Fairfax e Crimson Sweet), com 4 repetições de 50 sementes. Foram avaliados a germinação, crescimento de plântulas, degradação de reservas e sistema de proteção ao estresse. O estresse térmico causou efeitos deletérios em sementes de melancia com limites de germinação em temperaturas bem definidas, sendo 25 ºC a temperatura ideal, com o maior percentual de plântulas normais. Temperaturas sub (17 ºC) e supraótimas (30 ºC) apresentaram mais de 80 % de plântulas anormais. A atividade da enzima α-amilase é intensa apenas no início da germinação. Sob estresse térmico, os teores de prolina aumentam principalmente nos cotilédones.

The objetive of this work was to evaluate the effect of different bags and storage environments in maintaining the physiological quality of Erythrina velutina Willd. (mulungu) seeds. E. velutina seeds were collected, processed and placed in Kraft paper and transparent plastic bags,and stored at room temperature (30±5 ºC, 56±6% RH) and cold chamber (10±2 ºC, 74±4% RH) for up to 420 days. Recently harvested seeds and the ones stored for 90, 210, 300 and 420 days were evaluated for water content , germination and seedling vigor. It was observed that the water content of mulungu seeds was altered by storage periods and bagging; germination was not affected during the evaluation period for all environments and bagging. However, this did not mean successful seedling vigor or higher growth and dry biomass accumulation. Even with the decrease in seedling vigor according to storage time, in room temperature, in paper and plastic bags up to 420 days provided a better maintenance of the quality of mulungu seeds Made available in DSpace on 2019-05-18T00:33:07Z (GMT). No. of bitstreams: 1 bARBARA.pdf: 1148521 bytes, checksum: 9c14a1e79f1b0ee716296718e015f382 (MD5) Previous issue date: 2018

Brazilian guava (Psidium guineense Swartz.) is a plant species native from Brazil and present in all Brazilian biomes. This species occurs in the Caatinga biome as a wild fruit that has broad utility and can generate income, as well as provide material for breeding. The objective of this work was to study seed germination of guava accessions collected in two municipalities in Bahia. Seeds imbibition curve was studied. Also, seed germination and seedlings initial growth were evaluated for 44 days on different temperatures (15, 20, 25, 30 and 35 °C), fruit maturation, drying, pre-soaking and priming. Seeds imbibition curve was triphasic in which lag-phase begun after 30 hours imbibition and lasted 256 hours. An effect of guava genotype was observed in seeds physiological quality. Temperatures of 20 and 25 °C were ideal for guava seeds germination. Seeds pre-soaking and priming techniques are feasible to reduce germination time and increase seedling performance. Resumo O araçá (Psidium guineense Swartz) é uma espécie nativa do Brasil e presente em todos os biomas brasileiros. Ocorre na Caatinga de forma silvestre e é uma fruteira que apresenta ampla utilidade, podendo gerar renda além de fornecer material para o melhoramento genético. O objetivo deste trabalho foi estudar o processo germinativo de sementes de quatro acessos de araçá coletados em dois municípios da Bahia. Foi estudada a curva de embebição das sementes, bem como o efeito de diferentes temperaturas (15, 20, 25, 30 e 35°C), estágio de maturação, secagem, pré-embebição e condicionamento osmótico na germinação, vigor e crescimento inicial de plântulas dos acessos de araçá. A curva de embebição das sementes se mostrou trifásica, na qual a fase-lag iniciou após 30 h de embebição e durou 256 h. Foi observado um efeito dos genótipos na qualidade fisiológica das sementes de araçá. As temperaturas de 20 e 25 °C foram ideais para a germinação de sementes de araçá. As técnicas de pré-embebição e condicionamento osmótico das sementes reduziram o tempo de germinação e aumentaram o desempenho das sementes.

Plants produce and store many products of secondary metabolism that are released into the environment and can influence direct or indirectly on nearby organisms. Thus, this study investigated the allelopathic potential of extracted soil solution from an area with cover crops according to germination and early development of beggartick. Soil solution was extracted in an area where black oats, turnip and hairy vetch were grown. The concentrated solution was tested in sand substrate while the dilutions were tested in 100; 200; 300 and 400 ml L-1 germitest paper substrate, plus the control treatment on beggartick. Germination was tested for 10 days and the early development for 20 days. Twenty seeds or seedlings were distributed in gerbox, with three replications and the experimental design was completely randomized (CRD). Soil solution showed considerable changes on beggartick germination only in the last collections, mainly with extracted solution in an area cropped with turnip and hairy vetch. The results, in this case, were more significant when germitest was used than with sand substrate. Therefore, it is recommended these cover crops in crop rotation, aiming to reduce beggartick infestation in a long term. Made available in DSpace on 2017-07-20T23:57:15Z (GMT). No. of bitstreams: 1 SeedsGermination.pdf: 351912 bytes, checksum: 55f394648010932cd19d10d324548655 (MD5) Previous issue date: 2015-09-24

The objective of this study was to determine the efficacy of the SVIS® (Seed Vigor Imaging System) to determine squash seed vigor evaluated at different stages of maturation. ‘Jabras’ hybrid seeds, resulting from a cross between Cucurbita maxima (female parent) and Cucurbita moschata (male parent), were used in this study. Seeds extracted from fruit at different maturation stages (harvested at 15, 30, 45, 60 and 75 days after anthesis and stored or not for 20 days after each harvest) were subjected to the following determinations: 100 seed weight, germination, saturated salt accelerated aging, and SVIS®. This computerized system provided data on indexes of seedling vigor and uniformity of seedling development and on seedling growth. Results from SVIS® were similar to information from the other vigor tests performed in this study, detecting significant differences in performance among seeds during the maturation process. This indicates that SVIS® is a reliable alternative for obtaining consistent information on the physiological potential of squash seeds. Resumo: Este trabalho procurou verificar a eficiência do SVIS® (Seed Vigor Imaging System) para determinar o vigor de sementes de abóbora colhidas durante diferentes estádios de maturação. Utilizou-se a cultivar híbrida Jabras, proveniente do cruzamento entre Cucurbita maxima (linhagem feminina) e Cucurbita moschata (linhagem masculina). As sementes foram extraídas de frutos colhidos aos 15, 30, 45, 60 e 75 dias após a antese e armazenados, ou não, durante 20 dias após cada colheita e submetidas às seguintes determinações: massa de 100 sementes, geminação, envelhecimento acelerado com solução saturada de NaCl e SVIS®. Esta análise forneceu dados referentes aos índices de vigor e de uniformidade de desenvolvimento e ao crescimento das plântulas. Os resultados provenientes da análise computadorizada de imagens de plântulas foram semelhantes aos fornecidos pelos outros testes de vigor, detectando diferenças significativas no desempenho das sementes durante o processo de maturação. Isto demostra que o SVIS® é uma alternativa viável para a obtenção de informações consistentes sobre o potencial fisiológico de sementes de abóbora.

The physical quality and physiological performance of seeds may be influenced by numerous factors, including the moisture content at harvest and drying temperature. This study aimed at evaluating the physical quality and physiological performance of black bean seeds (BRS Campeiro cultivar), depending on the moisture content at harvest and drying air temperature. The experiment was conducted under a completely randomized design, in a 3 x 5 (moisture content at harvest x drying air temperature) factorial arrangement, with four replications. The samples were collected when the seeds reached the moisture contents of 35.2 %, 25.2 % and 16.6 %. After harvesting, the seeds were subjected to drying at temperatures of 30 ºC, 35 ºC, 40 ºC, 45 ºC and 50 ºC. The physical quality of the seeds was evaluated by determining the 1,000-seed weight and hectoliter weight. The physiological performance was evaluated by the germination speed index, germination first count, accelerated aging, dry matter, seedling shoot and root length and electrical conductivity. The increase in the drying temperature, regardless of the moisture content at harvest, reduces the physical quality and physiological performance of the seeds. When subjected to drying temperatures lower than 40 ºC, the seeds obtained from the earliest harvests show a better physical quality and physiological performance. RESUMO A qualidade física e o desempenho fisiológico de sementes podem ser influenciados por inúmeros fatores, dentre eles o teor de água na colheita e a temperatura de secagem. Objetivou-se avaliar a qualidade física e o desempenho fisiológico de sementes de feijão preto (cultivar BRS Campeiro), em função do teor de água na colheita e da temperatura do ar de secagem. O experimento foi realizado sob delineamento inteiramente casualizado, em esquema fatorial 3 x 5 (teor de água na colheita x temperatura do ar de secagem), com quatro repetições. As colheitas foram realizadas quando as sementes atingiram os teores de água de 35,2 %; 25,2 %; e 16,6 %. Após a colheita, as sementes foram submetidas a secagem nas temperaturas de 30 ºC, 35 ºC, 40 ºC, 45 ºC e 50 ºC. A qualidade física das sementes foi avaliada por meio da determinação do peso de mil sementes e do peso hectolitro. Já o desempenho fisiológico foi avaliado pelo índice de velocidade de germinação, primeira contagem de germinação, envelhecimento acelerado, matéria seca, comprimento da parte aérea e raiz das plântulas e condutividade elétrica. A elevação da temperatura de secagem, independentemente do teor de água na colheita, reduz a qualidade física e o desempenho fisiológico das sementes. Quando submetidas a temperaturas de secagem inferiores a 40 ºC, as sementes obtidas das colheitas realizadas antecipadamente apresentam melhor qualidade física e desempenho fisiológico.

RESUMO: O teste de condutividade elétrica é um teste de vigor de sementes utilizado para avaliar a qualidade das sementes e complementar o teste de germinação. O tamanho da amostra necessária para a estimação da média de condutividade elétrica de sementes é diretamente proporcional à variabilidade dos dados e confiabilidade desejada na estimativa. Uma técnica adequada para dimensionamento amostral é a utilização de intervalos de confiança, obtidos por reamostragem, com a vantagem de não dependerem da distribuição de probabilidade dos dados. O objetivo deste trabalho foi estimar o tamanho de amostra necessário para o teste de condutividade elétrica individual em sementes de girassol. Foram utilizados 7 lotes de sementes de girassol, sendo 3 da cultivar Hélio 250, 2 da cultivar BRS 323 e 2 da cultivar BRS 324. O teste de condutividade elétrica individual foi realizado com 400 sementes de cada lote, e o tamanho de amostra foi determinado pelo número de sementes a partir do qual a amplitude do intervalo de confiança de 95% (AIC95%) foi menor ou igual a 15, 20, 25, 30 e 35% da estimativa da média. O tamanho de amostra de 483, 257, 172, 115 e 85 sementes é suficiente para a estimativa da média de condutividade elétrica individual de sementes de girassol com AIC95% igual a 15, 20, 25, 30 e 35% da estimativa da média, respectivamente, para todos os lotes e períodos de embebição. ABSTRACT: The electrical conductivity is a seed vigor test used to assess seed quality and complement the germination test. The sample size required to estimate the average electrical conductivity of seeds is directly proportional to the variability of the data and desired reliability in the estimate. A suitable technique for sample dimension is the use of confidence intervals obtained by resampling. This technique has the advantage of not depending on the probability distribution of the data. The objective of this study was to estimate the sample size required for the individual electrical conductivity test in sunflower seeds. Seven lots of sunflower seeds were used: 3 lots of the cultivar Hélio 250, 2 of the BRS 323, and 2 of the BRS 324. The individual electrical conductivity test was conducted with each lot of 400 seeds, and the sample size was determined by the seed number from which the amplitude of the 95% confidence interval (AIC95%) was less than or equal to 15, 20, 25, 30, and 35% of the mean estimate. The sample size of 483, 257, 172, 115, and 85 seeds is sufficient to estimate the average of the individual electrical conductivity of sunflower seeds with an AIC95% equal to 15, 20, 25, 30, and 35% of the mean estimate, respectively, for all lots and soaking periods. Made available in DSpace on 2017-12-11T23:31:00Z (GMT). No. of bitstreams: 1 00068705brag16784499389.pdf: 872671 bytes, checksum: bfc3267462466ee7c31061cd1b40bd3b (MD5) Previous issue date: 2017-12-11