536 resultados para Cycad Pollination
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Apis mellifera honeybees are social insects of economic importance, by providing honeybee products, and by the pollination of natural areas of vegetation or agricultural areas. The constant use of pesticides, including the thiamethoxam, which is an insecticide belonging to the class of neonicotinoids with neurotoxic action, is subjecting pollinators to situations of severe stress, which has been evidenced by the decrease in the density of honeybees in many parts of the world. By these considerations, the present study aimed to assess the acute toxicity of thiamethoxam for newly emerged workers of A. mellifera, and to investigate the effect of sublethal doses of this insecticide on the survival time and its cytotoxicity to the brain and midgut to the honeybees. It was established the value of the lethal concentration 50 (LC50) equal to 4.28 ng thiamethoxam/μL of food and from it, the sublethal concentrations of 0.428 ng thiamethoxam/μL (CL50/10) and 0.0428 ng thiamethoxam/μL (CL50/100), which were used in bioassays of intoxication of the honeybees. After the bioassays the bees were dissected and the brain and midguts were collected to analyze possible morphological (staining with Hematoxylin-Eosin) and histochemical alterations (Xylidine Ponceau technique, and Feulgen and PAS reactions) caused by exposure to thiamethoxam, and to calculate the lethal time (LT50) for the workers. The duration of the bioassays was 8 days after beginning of feeding. The results obtained showed that the thiamethoxam is toxic to newly-emerged workers of A. mellifera, causing changes in survival time of individuals. This study also shown that the thiamethoxam causes morphological and histochemical alterations on the midgut and brain of workers. These alterations may be reflected in physiological and behavioral changes that can modify the operation of the colony
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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The objective of the present work was to estimate the genetic parameters of morphological traits, such as plant growth, fruit and seed production; and oil content and also to provide a source of superior genetic material for the breeding program of Jatropha curcas. For that, a J. curcas open pollination progeny test was set up in Sao Manuel Experimental Station, of College of Agricultural Sciences (FCA) of Sao Paulo State University (UNESP). The experimental design was of completely randomized blocks with 30 progenies, three replications, and eight plants per linear plot. We evaluated plants height (ALT), number of branches per plant (NRP), number of inflorescences per plant (NINE), number of fruits per plant (NF), weight of fruits (PE), weight of seeds (PS) and oil content % (TO). The software SELEGEN was the used to estimate the genetic parameters. The individual genetic variation coefficients (CVg) and progeny genetic variation coefficients (CVgp) at 24 months were 26.7% and 13.4% for height and 21.2% and 10.6% for number of branches. At 48 months the heritability coefficients among the progeny averages (h(mp)(2)) were 0.41 (ALT); 0.31 (NRP); 0.77 (NINF), and 0.44 (NF). The coefficient of heritability for individual plant level of oil content (TO %) was very low (h(a)(2) = 0.03), therefore, for the heritability of progeny means was higher than the individual level (h(mp)(2) = 0.37). Among progenies, some of them were superior for both, and seed production and oil content. We conclude that the present J. curcas population has enough genetic variability allowing obtaining gains through advanced generations.
Developmental Morphology of a Dimorphic Grass Inflorescence: The Brazilian Bamboo Eremitis (Poaceae)
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Premise of research.The highly specialized grass inflorescence varies with respect to phyllotaxis, with the reproductive meristem forming primary lateral branches that are either spirally arranged or distichous. The Brazilian bamboo Eremitis is highly unusual in that it has a dimorphic inflorescence, typically composed of an apical gynecandrous whorl of both male and female spikelets and basal whorls of male spikelets. Although not closely related to them, Eremitis shares some structural similarities with some early-divergent grasses.Methodology.We use SEM and LM to describe the development of the reproductive structures of Eremitis to clarify our understanding of the highly specialized grass inflorescence and flower.Pivotal results.Developmental studies show that the inflorescence of Eremitis is actually partially whorled and partially distichous. The apical whorl is abortive. The female spikelet is not terminal on the axis, in contrast with the majority of grasses. All the male spikelets are distichously attached to the inflorescence axis and separated into groups. There is a hollow style with two vascular bundles.Conclusions.The strong morphological similarities between Eremitis and some early-divergent grasses are here supplemented by several anatomical similarities, perhaps due to a shared pollination syndrome.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Population genetics theory predicts loss in genetic variability because of drift and inbreeding in isolated plant populations; however, it has been argued that long-distance pollination and seed dispersal may be able to maintain gene flow, even in highly fragmented landscapes. We tested how historical effective population size, historical migration and contemporary landscape structure, such as forest cover, patch isolation and matrix resistance, affect genetic variability and differentiation of seedlings in a tropical palm (Euterpe edulis) in a human-modified rainforest. We sampled 16 sites within five landscapes in the Brazilian Atlantic forest and assessed genetic variability and differentiation using eight microsatellite loci. Using a model selection approach, none of the covariates explained the variation observed in inbreeding coefficients among populations. The variation in genetic diversity among sites was best explained by historical effective population size. Allelic richness was best explained by historical effective population size and matrix resistance, whereas genetic differentiation was explained by matrix resistance. Coalescence analysis revealed high historical migration between sites within landscapes and constant historical population sizes, showing that the genetic differentiation is most likely due to recent changes caused by habitat loss and fragmentation. Overall, recent landscape changes have a greater influence on among-population genetic variation than historical gene flow process. As immediate restoration actions in landscapes with low forest amount, the development of more permeable matrices to allow the movement of pollinators and seed dispersers may be an effective strategy to maintain microevolutionary processes.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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This study aimed to verify the effect of vibration of plants in the production of fruits and seeds and in the physiological quality of the seeds of the “Malagueta” pepper in a protected cultivated area with open and closed sides. The experiment was conducted at the Experimental Farm of the School of Agronomic Sciences of Universidade Estadual Paulista (FCA/UNESP), located in the city of São Manuel (SP). Two treatments were carried out, which consisted of plants that did and did not undergo vibration. Plants were vibrated manually by swinging the wire attached to the supporting bamboo for about 5 seconds, twice a day for 11 weeks. The design was a randomized block with six repetitions. The same experiment was conducted in two protected environments, with and without anti-aphids screens on the sides, cultivated in the same season. For the comparison of environments, a combined analysis was performed considering each environment as a separate experiment. The characteristics evaluated were: weight and number of fruits per plant; weight, diameter and length of fruit; weight and amount of seeds per fruit; and plant height. For the analysis of seed quality, the characteristics evaluated were: germination percentage; first count of germination; dry matter of seedlings; seedling emergence in substrate; and seedling emergence speed index. Regardless of the environment, vibration affects the physiological quality of seeds. The presence of pollinator insects benefited the production and quality of “Malagueta” pepper seeds and increases the fruit weight.
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The aim of this study was to evaluate the production of eggplant fruit according to plant vibration in two types of protected environments, with and without an aphid-proof screen, preventing or permitting the entry of pollinators. Two eggplant hybrids (Roxelle, clear purple color and round shape fruits, and Kokushi, purple color and elongated fruits), two vibration treatments (with or without plant vibration), and two environments (with or without screen) were assessed. It was concluded that the presence of insects in the open environment increases marketable fruit yield only in hybrid Roxelle (2120 and 1172 g plant-1, with and without insects, respectivelly), the number of seeds per fruit in both hybrids in treatment without plant vibration (average of 584 and 110 seeds, with and without insects, respectivelly), and that plant vibration may partially replace the absence of pollinator insects in a closed environment protected with a screen, with an increase in fruit yield.
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Controlled pollination is an important tool in a forest genetic improvement program, which permits to choose parents and make specific crosses maximizing gains and providing superior genotypes in less time than conventional pollination. To verify the needs of the forest companies regarding the conduction of controlled pollination orchards in the breeding program, a specific questionnaire was sent in September 2011 to companies associated to IPEF. The objective of the questionnaire was to collect basic information about the current situation of controlled pollination orchards and check the main difficulties and demands related. It was found that use of the controlled pollination orchard has begun to be used by companies in the Brazilian forest sector just a few years ago and is considered to be very important in breeding programs in order to shorten the time to obtain new genotypes; but there is still need of crucial information regarding the management of these orchards. The main demands are: Basic concepts of flowering induction; homogeneity of flowering; hormonal induction and alternative techniques for flowering; relationship between management and genotypes used; variations in the flowering of different genotypes; management of the orchard in the different phenological phases; process of grafting typesand interaction between graft and rootstock, irrigation systems; species identification and flowering map.