Fenologia, produção e qualidade dos frutos de cultivares de mangueira em condições subtropicais

Pós-graduação em Agronomia (Horticultura) - FCA

Avaliação da qualidade fisiológica de sementes de milho de classes de tamanho misturadas para fins de semeadura fluidizada

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Teste de condutividade elétrica e presença de patógenos em sementes de soja

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Absorção de água, germinação e dormência de sementes de mucuna preta

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Danos em sementes de milho em função do mecanismo dosador de semeadora-adubadora

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

População de plantas, ferrugem asiática e produção de soja

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Aspectos ecofisiológicos da germinação, sobrevivência e desenvolvimento inicial de Styrax camporum Pohl. (Styracaceae)

Pós-graduação em Ciências Biológicas (Biologia Vegetal) - IBRC

Aspectos da ecologia do Cuxiú de Uta Hick, Chiropotes Utahickae (Hershkovitz, 1985), com ênfase na exploração alimentar de espécies arbóreas da ilha de germoplasma, Tucuruí-PA

A criação da Usina Hidrelétrica de Tucuruí em 1985, inundou uma área de 2.400 Km² de floresta, originando centenas de ilhas de tamanhos diferentes, onde diversos organismos, dentre eles os cuxiús (Chiropotes spp.), tiveram suas populações fragmentadas. A área de estudo, ilha de Gennoplasrna, possui 129 ha e abriga uma população de Chiropotes utahickae, atualmente com 23 membros, já estudada por Santos (2002). O objetivo principal deste estudo foi descrever aspectos da ecologia do cuxiú de Uta Hick e caracterizar a exploração alimentar de espécies arbóreas. A metodologia utilizada foi baseada em oito dias de coleta mensal de dados, utilizando-se o método de varredura instantânea de um minuto de duração e cinco de intervalo, aplicado paralelamente ás amostragens de árvore-focal e fruto-focal, intercalando-se estes dois tipos. As principais categorias comportamentais foram alimentação, deslocamento, forrageio, repouso e interação social. Foram obtidos 11.277 registros de varredura, 259 de árvore-focal e 711 de fruto-focal durante o período de março a agosto de 2004. Foram gastos 50,6% do tempo em deslocamento, 31,9% em alimentação, 10,6% em repouso, 5,4% em forrageio e 1,2% em interação social. A dieta foi composta principalmente de semente imatura (31,7%), mesocarpo imaturo (21,2%), fruto maduro (18,3%) e flores (14,4%). A comparação com o estudo de Santos (2002) sugere diferenças longitudinais e sazonais. Os frutos explorados variaram de 0,4 cm a 15,3 cm de comprimento e as sementes, de 0,1cm a 2,3 cm. Os cuxiús foram considerados predadores para 74,2% das 31 espécies analisadas. Não houve relação significativa entre o tamanho das sementes e o tipo de interação. Também não existiu relação significativa entre a distância de deposição das sementes e o tamanho destas, sugerindo que o transporte de sementes pelos cuxiús pode estar ligado a outros fatores (dimensão da copa, tamanho do subagrupamento). Após vinte anos de isolamento, os cuxiús pareceram apresentar um padrão comportamental típico do gênero Chiropotes. Esta tolerância ao ambiente fragmentado, pareceu ser evidenciada nesse estudo, pelo intenso consumo do mesocarpo imaturo de ingás (Inga spp.) e de flores de castanheira (Bertholletia excelsa). Flores parecem ser um recurso importante para os cuxiús da área de influência do reservatório de Tucuruí (Santos, 2002; Silva, 2003). Este trabalho vem contribuir para o conhecimento da ecologia da espécie, ressaltando que o monitoramento das populações nas áreas do reservatório de Tucuruí, precisa ser continuado a fim de que se reúna mais informações a respeito da sua organização social, dieta e interferência na comunidade vegetal, necessárias para o planejamento de medidas de manejo e conservação.

Qualidade fisiológica de sementes de milho doce classificadas pela espessura e largura

Sweet maize seeds present lower physiologic quality, when compared to regular maize seeds, due to the influence of several features, such as the seed size and shape. Thus, this study aimed at evaluating the seed physiologic quality of two sweet maize cultivars (BR-401 and BR-402), separately classified according to thickness, by using slotted screen sieves (8/64 x 3/4, 9/64 x 3/4, 10/64 x 3/4, 11/64 x 3/4, 12/64 x 3/4 and 13/64 x 3/4), and width, with round screen sieves (17/64, 18/64, 19/64, 20/64, 21/64 and 22/64). For each cultivar, sorted lots were compared with the unrated batch, following a completely randomized design, in a 2x7 factorial scheme, with four replications. The biometric parameters evaluated were sieve retention, 100 seeds weight and water content. The physiologic quality was determined according to the first counting, germination, cold test, accelerated aging, electric conductivity and seedling emergence in the field. The classification with sieves improved the physiologic quality of sweet maize seeds. Seeds with intermediate thickness, for both cultivars, generally presented greater vigor. Concerning width, larger seeds, for the BR-401 cultivar, and intermediate seeds, for the BR-402 cultivar, showed better physiologic quality.

Seasonal variation in the fate of seeds under contrasting logging regimes

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Poda apical para produção de frutos e sementes de abóbora

The tip pruning stimulates the emission of lateral shoots, thus can produce higher number of flowers, fruits and seeds. This work aimed to evaluate the effect of apex pruning on fruit and seed production in pumpkin. The treatments consisted of plants without pruning, with pruning in the sixth, eighth and tenth node of main stem. The experimental design was a randomized block, with six replications. It was studied a line of pumpkin of the Germplasm Bank of the Universidade Estadual Paulista/Faculdade de Ciências Agronômicas. The characteristics evaluated were: number of branches per plant and fruit position in branches of the plant production (number and weight) of fruits per plant, fruit yield, fruit average weight, fruit length and diameter, seed weight per fruit, seed yield and quality (germination test, first count, thousand seed weight, emergence, speed of emergence and accelerated aging). There was a significant difference only for number of secondary branches per plant and thousand seed weight, with larger values for plants that have not been pruned. It was obtained high average of germination (94%) and good fruit (16.9 t ha-1) and seed (148 kg ha-1) yield. The apex pruning does not influence the production of fruits and seeds, as well as the physiological seed quality in pumpkin.

Adaptation and Constraint in the Plant Reproductive Phase

Conservatism is a central theme of organismic evolution. Related species share characteristics due to their common ancestry. Some concern have been raised among evolutionary biologists, whether such conservatism is an expression of natural selection or of a constrained ability to adapt. This thesis explores adaptations and constraints within the plant reproductive phase, particularly in relation to the evolution of fleshy fruit types (berries, drupes, etc.) and the seasonal timing of flowering and fruiting. The different studies were arranged along a hierarchy of scale, with general data sets sampled among seed plants at the global scale, through more specific analyses of character evolution within the genus Rhamnus s.l. L. (Rhamnaceae), to descriptive and experimental field studies in a local population of Frangula alnus (Rhamnaceae). Apart from the field study, this thesis is mainly based on comparative methods explicitly incorporating phylogenetic relationships. The comparative study of Rhamnus s.l. species included the reconstruction of phylogenetic hypotheses based on DNA sequences. Among geographically overlapping sister clades, biotic pollination was not correlated with higher species richness when compared to wind pollinated plants. Among woody plants, clades characterized by fleshy fruit types were more species rich than their dry-fruited sister clades, suggesting that the fleshy fruit is a key innovation in woody habitats. Moreover, evolution of fleshy fruits was correlated with a change to more closed (darker) habitats. An independent contrast study within Rhamnus s.l. documented allometric relations between plant and fruit size. As a phylogenetic constraint, allometric effects must be considered weak or non-existent, though, as they did not prevail among different subclades within Rhamnus s.l. Fruit size was correlated with seed size and seed number in F. alnus. This thesis suggests that frugivore selection on fleshy fruit may be important by constraining the upper limits of fruit size, when a plant lineage is colonizing (darker) habitats where larger seed size is adaptive. Phenological correlations with fruit set, dispersal, and seed size in F. alnus, suggested that the evolution of reproductive phenology is constrained by trade-offs and partial interdependences between flowering, fruiting, dispersal, and recruitment phases. Phylogenetic constraints on the evolution of phenology were indicated by a lack of correlation between flowering time and seasonal length within Rhamnus cathartica and F. alnus, respectively. On the other hand, flowering time was correlated with seasonal length among Rhamnus s.l. species. Phenological differences between biotically and wind pollinated angiosperms also suggested adaptive change in reproductive phenology.

Experimentelle Untersuchung von Phasenübergängen im kolloidalen Modellsystem harter Kugeln

Die vorliegende Arbeit behandelt den fluid-kristallinen Phasenübergang sowie den Glasübergang anhand von kolloidalen Hart-Kugel(HK)-Modellsystemen. Die Untersuchungen erfolgen dabei im Wesentlichen mit unterschiedlichen Lichtstreumethoden und daher im reziproken Raum. rnDie Analyse der Kristallisationskinetik zeigt, dass es bei der Kristallisation zu signifikanten Abweichungen vom Bild der klassischen Nukleationstheorie (CNT) kommt. Diese geht von einem einstufigen Nukleationsprozess aus, wohingegen bei den hier durchgeführten Experimenten ein mehrstufiger Prozess beobachtet wird. Vor der eigentlichen Kristallisation kommt es zunächst zur Nukleation einer metastabilen Zwischenphase, sogenannter Precursor. In einer zweiten Stufe erfolgt innerhalb der Precursor die eigentliche Nukleation der Kristallite. rnDurch weitere Analyse und den Vergleich des Kristallisations- und Verglasungsszenarios konnte das Konzept der Precursornukleation auf den Vorgang der Verglasung erweitert werden. Während die Kristallnukleation oberhalb des Glasübergangspunktes zum Erliegen kommt, bleibt der Prozess der Precursornukleation auch bei verglasenden Proben erhalten. Ein Glas erstarrt somit in einem amorphen Zustand mit lokalen Precursorstrukturen. Die Korrelation der gemessenen zeitlichen Entwicklung der strukturellen sowie der dynamischen Eigenschaften zeigt darüber hinaus, dass das bisher unverstandene Ageing-Phänomen von HK-Gläsern mit der Nukleation von Precursorn zusammenhängt.rnEin solches mehrstufiges Szenario wurde bereits in früheren Veröffentlichungen beobachtet. Die im Rahmen dieser Arbeit durchgeführten Messungen ermöglichten erstmals die Bestimmung von Kristallnukleationsratendichten (Kristall-NRD) und Ratendichten für die Precursornukleation bis über den Glasübergangspunkt hinaus. Die Kristall-NRD bestätigen die Resultate aus anderen experimentellen Arbeiten. Die weiteren Analysen der Kristall-NRD belegen, dass die fluid-kristalline Grenzflächenspannung bei der Nukleation entgegen den Annahmen der CNT nicht konstant ist, sondern mit ansteigendem Volumenbruch linear zunimmt. Die Erweiterung der CNT um eine linear zunehmende Grenzflächenspannung ermöglichte eine quantitative Beschreibung der gemessenen Kristall- sowie der Precursor-NRD, was den Schluss zulässt, dass es sich in beiden Fällen um einen Boltzmann-aktivierten Prozess handelt. rnUm die beobachteten Abweichungen des Nukleationsprozesses vom Bild der CNT näher zu untersuchen, wurden die kollektiven Partikeldynamiken in stabilen Fluiden und metastabilen Schmelzen analysiert. Im klassischen Bild wird angenommen, dass die kollektive Partikeldynamik beim Vorgang der Nukleation keine Rolle spielt. Anhand der Resultate zeigen sich Abweichungen in der Dynamik stabiler Fluide und metastabiler Schmelzen. Während die kollektive Partikeldynamik in der stabilen Schmelze von der Struktur entkoppelt ist, tritt oberhalb des Phasenübergangspunktes eine Kopplung von Struktur und Dynamik auf. Dabei treten die Abweichungen zunächst in der Umgebung des ersten Strukturfaktormaximums und somit bei den am stärksten besetzten Moden auf. Mit steigender Unterkühlung nehmen die Anzahl der abweichenden Moden sowie die Stärke der Abweichungen zu. Dieses Phänomen könnte einen signifikanten Einfluss auf den Nukleationsprozess und somit auf die Kristallisationskinetik haben. Die Analyse der Dynamik im stabilen Fluid zeigt darüber hinaus Hinweise auf eine Singularität bei Annäherung an den fluid-kristallinen Phasenübergangspunkt.rnDes Weiteren wurden im Rahmen der vorliegenden Arbeit erstmals Ratendichten für die heterogene Nukleation eines HK-Systems an einer flachen Wand mittels statischer Lichtstreuung (SLS) bestimmt. Die Ergebnisse der Messung zeigen, dass die Nukleationsbarriere der heterogenen Nukleation annähernd Null ist und folglich eine vollständige Benetzung der Wand mit einer kristallinen Monolage vorliegt. Die Erweiterung der Untersuchungen auf gekrümmte Oberflächen in Form von sphärischen Partikeln (Seeds) stellt die erste experimentelle Arbeit dar, die den Einfluss eines Ensembles von Seeds auf die Kristallisationskinetik in HK-Systemen untersucht. Die Kristallisationskinetik und die Mikrostruktur werden abhängig von Größe und Anzahldichte der Seed-Partikel signifikant beeinflusst. In Übereinstimmung mit konfokalmikroskopischen Experimenten und Simulationen spielt dabei das Radienverhältnis der Majoritäts- zur Minoritätskomponente eine entscheidende Rolle.

Asociación entre caracteres biométricos y calidad fisiológica en semillas de tomate (Solanum lycopersicum L.)

La clasificación de las semillas de especies olerícolas se realiza principalmente por peso y tamaño, con criterios similares a los aplicados en cereales y leguminosas, en que se asocia positivamente estos atributos físicos con la calidad fisiológica. No obstante lo anterior, en diversas especies de hortalizas la información es escasa y contradictoria al respecto, lo que motiva la realización de la presente investigación. En semillas de tomate (Solanum lycopersicum L.) se determinó el efecto del peso y tamaño sobre la calidad fisiológica expresada como germinación y vigor. Además, se correlacionaron los resultados de las pruebas de evaluación de calidad fisiológica y se describieron variables del crecimiento y desarrollo. Se utilizaron lotes de diferentes variedades de semillas híbridas de cuatro temporadas, producidas en un clima templado cálido con lluvias invernales y estación seca prolongada (32º 54’ y 34° 21´ latitud Sur). Se midió peso y tamaño de semillas, además en dos temporadas se evaluaron las características internas de área y peso de embrión y área de endospermo. Se determinó la calidad de las semillas con la prueba de germinación y según fuera el año de estudio se midió vigor con las pruebas de envejecimiento acelerado, de plantas útiles al trasplante y de plántulas emergidas. Con análisis de imágenes y rayos X se extrajeron datos del tamaño externo e interno de las semillas y plántulas. Los lotes se compararon mediante análisis de varianza y las medias con la prueba de Tukey, la asociación entre dos variables se determinó con correlaciones de Pearson, las variables de peso y tamaño de la semilla y su relación con las pruebas de calidad, se analizaron mediante regresiones múltiples. Se utilizó un nivel de significación de 0,05 de probabilidad. Los resultados indicaron que el tamaño y no el peso de las semillas de tomate, diferenciaron calidad entre lotes en las diversas variedades. La prueba de germinación tuvo una baja sensibilidad para discriminar lotes, además de una escasa correlación con las características físicas de las semillas, cuando hubo asociación, la relación fue débil y negativa. La prueba de vigor de envejecimiento acelerado diferenció lotes y presentó escasa asociación con las características físicas de las semillas. El número de semillas germinadas en la prueba de envejecimiento acelerado se explicó por el efecto del tamaño de las semillas, mientras que las fracciones de descarte se asociaron con el peso de las mismas. La prueba de vigor de plantas útiles al trasplante no discriminó entre lotes. Tuvo una asociación débil con el peso y tamaño de las semillas. El modelo asociado a esta relación explicó con un alto coeficiente de determinación que el peso de la semilla influyó sobre la emergencia temprana, mientras que la relación fue menor y negativa con plantas de mayor desarrollo. La prueba de vigor de plántulas emergidas discriminó lotes de semillas con plántulas de 3 a 5 días después de siembra. Hubo escasa y débil asociación entre esta prueba y las características de peso y tamaño las semillas. El modelo de predicción de plántulas emergidas fue particular en cada temporada, cuando hubo un coeficiente de determinación alto influyó negativamente el peso o tamaño de la semilla. Entre las pruebas de calidad fisiológica evaluadas en semillas de tomate hubo escasas correlaciones significativas. Entre germinación y vigor las correlaciones significativas fueron débiles y sólo se encontraron en algunas temporadas de evaluación. Entre las pruebas de vigor no hubo asociación. En las pruebas de vigor de plantas útiles al trasplante y de plántulas emergidas, los cotiledones alcanzaron el mayor porcentaje de materia seca y se correlacionaron fuertemente con la materia seca total. En la prueba de plántulas emergidas la materia seca de las radículas diferenció parcialmente lotes de semillas al igual que la longitud total y de las radículas. La longitud de la radícula se correlacionó fuertemente con la longitud total de plántulas. ABSTRACT Seed selection for olericultural species is mainly carried out considering weight and size with similar criteria to those applied in cereals and legumes where size and physiological quality are favorably associated. However, information about several species is limited and contradictory regarding the above, leading to the present research. In tomato (Solanum lycopersicum L.) seeds, the effect of weight and size on the physiological quality expressed as germination and vigor was determined. In addition, results of quality evaluation tests were correlated and variables of growth and development were described. Batches of hybrid seeds from four seasons were used. These seeds were produced in a mild warm climate with winter rainfalls and long dry season (32º 54’ and 34° 21´South Latitude). Seed weight and size were determined, additionally internal characteristics such as embryo area and weight as well as endosperm area were evaluated in two seasons. The quality of seeds was established using the germination test and, depending on the year of the study, vigor was measured through accelerated aging tests for plants useful for transplanting and emerged seedlings. Using imaging analysis and X rays, data regarding external and internal size of seeds and seedlings were obtained. Batches were compared through ANOVA and means using Tukey’s test; the association between both variables was determined with Pearson correlations, whereas variables of seed weight and size and their relation to quality tests were analyzed through multiple regressions. A significance level of 0.05 probability was used. Results showed that the size (but not the weight) of tomatoes differentiates quality between batches from several seasons. The germination test was not sensitive enough to discriminate batches in addition to having a limited correlation with the characteristics of seeds, when they were associated, the relation was weak and unfavorable. Vigor test for accelerated aging made the difference between batches and presented low association with physical characteristics of the seeds. The number of germinated seeds in the accelerated aging test was explained by the effect of the seed size, whereas cull fractions were associated with their weight. The vigor test of plants useful for transplanting did not discriminate between batches. The association with seed weight and size was weak. The model associated to this relation explained, with a high coefficient determination, that the seed weight had influence on early emergence, whereas the relation was minor and unfavorable with more developed plants. Vigor test of emerged seedlings discriminated batches of seeds with seedlings of 3 to 5 days after sowing. There was a limited and weak association between this test and the characteristics of seed weight and size. The prediction model for seedlings emerged was particular in each season, when the determination coefficient was high, seed weight and size influenced negatively. Among the physiological quality tests evaluated in tomato seeds, significant correlations were negligible. Between germination and vigor, significant correlations were poor, being only found in some evaluation seasons. There was no association in the vigor tests. In vigor tests for plants useful for transplanting and emerged seedlings, cotyledons reached the highest percentage of dry matter and were strongly correlated with total dry matter. In the test of emerged seedlings, dry matter of radicles partially differentiated batches of seeds as well as total length and radicles. Radicle length was strongly correlated with total seedlings length.

Direct seeding to restore rainforest species: Microsite effects on the early establishment and growth of rainforest tree seedlings on degraded land in the wet tropics of Australia

Reforestation in tropical areas is usually attempted by planting seedlings but, direct seeding (the artificial addition or sowing of seed) may be an alternative way of accelerating forest recovery and successional processes. This study investigated the effects of various sowing treatments (designed to create different microsite conditions for seed germination) and seed sizes on the early establishment and growth of directly sown rainforest tree species in a variety of experimental plots at three sites in the wet tropical region of north-cast Queensland, Australia. The different sowing treatments were found to have significant effects on seedling establishment. Broadcast sowing treatments were ineffective and resulted in very poor seedling establishment and high seed wastage. Higher establishment rates occurred when seeds were buried. Seed size was found to be an important factor affecting establishment in relation to micro-site condition. In general, larger seeded species had higher establishment rates at all three sites than species of small and intermediate seed size, but only in sowing treatments where seeds were buried. Overall these results suggest that direct sowing of seed can be used as a too] to accelerate recolonisation of certain rainforest tree species on degraded tropical lands, but initial success will be dependent on the choice of sowing method and its suitability for the seed types selected. The results also indicate that the recruitment of naturally dispersed tree species at degraded sites is likely to be severely limited by the availability of suitable microsites for seed germination. Consequently the natural recovery of degraded sites via seed rain can be expected to be slow and unpredictable, particularly in areas where soil compaction has occurred. (c) 2006 Elsevier B.V. All rights reserved.