Submitted by (edna.saturno@ufrpe.br) on 2016-12-19T15:34:38Z No. of bitstreams: 1 Orlando de Oliveira dos Santos.pdf: 1008703 bytes, checksum: 47b747aa1eaa483ff683caadd85cd715 (MD5) / Made available in DSpace on 2016-12-19T15:34:38Z (GMT). No. of bitstreams: 1 Orlando de Oliveira dos Santos.pdf: 1008703 bytes, checksum: 47b747aa1eaa483ff683caadd85cd715 (MD5) Previous issue date: 2013-07-30 / This study aimed to evaluate the ecophysiological characteristics of the species Zea mays, Sorghum bicolor and Brachiaria decumbens under water stress conditions in a greenhouse. The experiment was conducted in a completely randomized design, using three species, Zea mays, Sorghum bicolor and Brachiaria decumbens, with 10 plants of each species under two water regimes (control and stress). The parameters evaluated were: soil moisture (Smoisture) vapor pressure deficit (VPD), leaf water potential (Ψleaf); gas exchange (net CO2 assimilation (A), stomatal conductance (gs), transpiration (E) and intrinsic water use efficiency (WUEi)), chlorophyll a fluorescence (photochemical quenching (qP), non-photochemical quenching (NPQ), electron transport rate (ETR) and maximum quantum efficiency in Photosystem II (Fv / Fm)); and biochemical analysis (total soluble carbohydrate (TSC), total free aminoacids (TFA), total soluble protein (TSP), chlorophyll a (Chla), chlorophyll b (Chlb) and carotenoids (car). The data of leaf water potential and soil moisture were submitted to Student's T test with a significance level of 5%. When subjected to 21 days of water deficit, the species Z. mays declined 248% in Ψleaf, 87% in stomatal conductance, 53% in net CO2 assimilation, 84% in transpiration, 156% in intrinsic water use efficiency, 54% in photochemical quenching, 67% in electron transport rate, 10% in Fv / Fm and 17% in chlorophyll a; S. bicolor showed a decrease in Ψleaf about 212%, 42% in stomatal conductance, 26% in net CO2 assimilation, 31% in transpiration, and 40% in electron transport rate; and in the species B. decumbens was observed a decrease in Ψleaf about 105%, 36% in stomatal conductance, 31% in net CO2 assimilation, 24% in transpiration, 34% in intrinsic water use efficiency, 53% in photochemical quenching, 56% in electron transport rate, 54% in total free amino acid content. The species which presented the smallest decrease related to the evaluated parameters was S. bicolor. From 14 analyzed parameters, S. bicolor showed decrease in 5 of them, while the other two species reduced their rates in 9 at least. / Este trabalho teve como objetivo avaliar as características ecofisiológicas das espécies Zea mays, Sorghum bicolor e Brachiaria decumbens sob condição de déficit hídrico em casa de vegetação. O experimento foi conduzido em delineamento inteiramente casualizado, utilizando três espécies forrageiras- Zea mays, Sorghum bicolor e Brachiaria decumbens- com 10 plantas de cada espécie sob dois regimes hídricos (controle e estresse). Os parâmetros avaliados foram: umidade do solo (Usolo), deficit de pressão de vapor (DPV), potencial hídrico foliar (Ψfoliar); trocas gasosas (assimilação líquida de CO2 (A), condutância estomática (gs), transpiração (E) e eficiência intrínseca do uso da água (EUA)); fluorescência de clorofila a (quenching fotoquímico (qP), quenching não fotoquímico (NPQ), taxa de transporte de elétrons (ETR) e eficiência quântica máxima no fotossistema II (Fv / Fm)); e análises bioquímicas (carboidratos solúveis totais (CST), aminoácidos livres totais (ALT), proteínas solúveis totais (PST), clorofila a (Chla), clorofila b (Chlb) e carotenóides (car)). Os dados de potencial hídrico foliar e umidade do solo foram submetidos ao teste T, com nível de significância de 5%. Os demais parâmetros foram submetidos à ANOVA fatorial (Regime hídrico x Turno diário) e quando necessário às médias foram comparadas pelo teste de Student Newman Keul’s com nível de significância de 5%. Quando submetida à 21 dias de déficit hídrico, a espécie Z. mays apresentou uma queda no Ψ foliar de 248%, na condutância estomática de 87 %, na assimilação líquida de CO2 de 53%, na transpiração de 84%, na eficiência do uso da água de 156%, no quenching fotoquímico de 54%, na taxa de transporte de elétrons de 67%, na Fv / Fm de 10% e na Clorofila a de 17%; já o S. bicolor apresentou queda no foliar de 212%, na condutância estomática de 42%, na assimilação líquida de CO2 de 26%, na transpiração de 31% e na taxa de transporte de elétrons de 40%; E na espécie B. decumbens foi observado queda no Ψ foliar de 105%, na condutância estomática de 36%, na assimilação líquida de CO2 de 31%, na transpiração de 24%, na eficiência do uso da água de 34%, no quenching fotoquímico de 53%, na taxa de transporte de elétrons de 56% e no teor de aminoácidos livres totais de 54%. A espécie que apresentou a menor queda relacionada aos parâmetros avaliados foi o S. bicolor. De 14 parâmetros analisados S. bicolor apresentou queda em 5, enquanto que as outras duas espécies avaliadas suas taxas reduziram pelo menos em 9 parâmetros.

A thesis report submitted in partial fulfilment of the requirements for the degree in Master of Science in GIS and Remote Sensing Faculty of Science University of the Witwatersrand. March 2017 Johannesburg, South Africa / Grass nitrogen is the main indicator of forage conditions in a rangeland environment. The main objectives of the research were to map the quality and quantity of common grass communities and to predict Nitrogen (N) content across different grass communities. A machine-learning algorithm of Support Vector Machines (SVM) was tested in the mapping of grass quality and quantity. An overall accuracy of 72.68% was achieved for the mapping analysis which demonstrated the capability of the Sentinel-2 10m resolution in discriminating the spectral properties of different grass communities. The foliar nitrogen was predicted using univariate regression, stepwise multiple linear regression (SMLR), multivariable regression methods, partial least square regression (PLSR) and random forest (RF). Foliar N was predicted using multivariate regression models; the best model was selected based on the highest coefficient of determination (R2) value, and the low root mean square error (RMSE). The best RF model for foliar N estimation was based on the simple ratio (SR) index because the model attained the highest prediction accuracy of 35%. The study demonstrates the applicability of Sentinel-2 MSI utility in mapping and estimation of leaf N at a landscape scale .The results of both regression models (univariate and multivariate) such as random forest and partial least squares indicated that the inclusion of the Sentinel-2 MSI red edge bands provides an opportunity to accurately map and estimate leaf bio-chemical composition using remote sensing techniques. / MT 2017

Large populations o+ black grass bugs, Labops hesperius Uhler, have been observed on extensive acreages o+ range lands. These bugs cause severe damage to the range grasses, lowering their palatability and productivity. This study was to determine whether morphological differences among breeding lines o+ grass species or interspecific hybrids could be correlated with the feeding behavior o+ black grass bugs. I+ so, plant breeders should be able to develop resistant cultivars. To explore this possibility, cultivars and synthetics o+ range grasses, representing the genera, Agropyron, Dactylis, Phalaris and Poa, were exposed to di++erent instar stages was examined under a scanning electron microscope. Leaf pubescence (trichomes) varied in density and size and appeared to be associated with resistance of plants in the genera, Agropyron, to the Labops nymphs (instar stages II and III> but had no relation with the feeding behavior of adult black grass bugs. Plant leaves of the general, Dactylis and Phalaris, were smooth (few and small if any trichomes> and were the least preferred of any of the grasses by all stages of the bugs. Trichomes on leaves of other genera were varied in density and size. Based on percent damage, preference by the nymphs was for the species with intermediate sized trichomes. The adult bugs showed no discrimination in their feeding behavior. Field grown plants developed more trichomes per unit leaf area and appeared to have thicker surface waxes than the same species grown in the greenhouse. For this reason, nymph feeding habits may be different in the field than in the greenhouse. Future studies should perhaps investigate (1) first stage nymph activity on field plants and (2) palatability and/or chemical differences of the grasses.

Allergies are considered atopic diseases, or diseases that cause the immune system to create an abnormal amount of IgE antibodies when the body is exposed to an allergen. Allergies affect many people around the world, however many studies have shown a higher rate of allergy in developed countries when compared to developing countries. This discrepancy is hypothesized to be in part because of a decrease in parasitic infections, which have shown to have a protective effect for autoimmune-type diseases, like allergies. There are not many long-term, effective allergy treatments, however a promising allergen-specific immunotherapy technique uses a vaccine that targets B cell epitopes with the hope of increasing the amount of IgG antibodies as opposed to IgE specific antibodies to decrease the likelihood of an allergic reaction. This paper proposes a study that combines the protective effects of a parasite infection with a helminth infection and a B cell epitope vaccination, an already studied BM32 vaccine, to improve allergy symptoms of those with grass pollen allergy. This combination treatment will aim to decrease the number of symptomatic days, eosinophil count found at a scratch test site, and IgE antibodies found within the blood in grass pollen allergic people during peak grass pollen season.

For decades man has been interested in selection and hybridization of crop plants, but it has not been until in comparatively recent years that anything of importance has been done toward the improvement of perennial forage grasses. Replies to questionnaries on grass breeding submitted to various agricultural institutions in 1936 revealed the fact that selection for improvement was then under way with a large number of grasses. Limited activities in this field have been in progress for 16 years or more, but organized and intensive grass breeding activities, for the most part, have been inaugurated only within the last ten years. Many improved strains of grasses have been developed by selective breeding in foreign countries but very few of these have shown outstanding value in the United States. In fact, they are generally inferior. There is a great deal of interest at the present time in this country in the field of grass breeding, but the smallness of the floral parts of some grasses makes the work of controlled hybridization tedious and slow. A simple, inexpensive, accurate method for bulk hybridization would be useful and would speed up the work. The study herein reported was designed to throw further light on the possibility of bulk hybridization. The technic involves immersion of inflorescences in water heated to specific temperatures to effect enactivation of pollen. As a necessary corollary, the desired pollen is then applied by any of several methods. Several investigators, mentioned below, have shown that controlled heat treatments applied to inflorescences near the time of anthesis are effective in seriously reducing the viability of pollen without having a similar effect on the female gametophyte. However, none has demonstrated good female fertility following complete male sterilization. It has become apparent that influences of the plants' environment other than the heat of the emasculation treatment must be taken into consideration. In the present study, which was conducted on three important forage grasses, smooth bromegrass (Bromus intermis), crested wheatgrass (Agrpyron cristatum), and bluestem wheatgrass (Agropyron smithii), the general findings of earlier investigators are substantiated and in addition evidence is presented to show (1) the sterilizing effect of the isolation bag and (2) the existence of a daily cycle in the efficiency of emasculation of treatments at critical temperatures.

I studied the acquisition of foraging skills by lambs eating shrub or grass in three experiments. The general approach was to isolate those skills involved in prehending forage from those related to the acceptance of novel foods. Treatment lambs received 15 times more exposure to grass or shrub than did control lambs. Lambs were tested in 2.5 x 2.5 meter monocultures of shrub or grass 5 min/d, on two separate occasions. Height, bulk density and spatial arrangement of plant material were controlled during testing. In Experiment 1, I studied the acquisition of foraging skills by lambs on monocultures of shrubs. I found that inexperienced lambs ingested less forage per unit time than experienced lambs because they had less developed prehension skills. Lambs were more successful at plucking individual leaves than breaking twigs from branches or stripping 1 eaves. Lambs emphasized prehension patterns that were most successful. In Experiment 2, I explored the extent to which foraging skills gained on shrub or grass are specific to shrub or grass. Grass-experienced lambs were more successful at prehending and ingesting grass than were shrub experienced lambs. No statistical differences were observed between shrub- and grass-experienced lambs at prehending and ingesting shrub although numerical values were higher for shrub- than grass-experienced lambs. I hypothesize that a relationship exists between plant form, prehension pattern and foraging experience. In Experiment 3, I studied the degree to which lambs experienced with grass or shrub vary in their ability to prehend and ingest vegetative and flowering grass. Grass- and shrub-experienced lambs ingested more flowering than vegetative grass per unit time. Grass-experienced lambs were more efficient than shrub-experienced lambs at prehending and ingesting vegetative and flowering grass. Shrub-experienced lambs experienced more difficulty at prehending flowering compared to vegetative grass while grass-experienced lambs did not.

O bioma Pampa é um dos biomas mais diversos em espécies de gramíneas do mundo. Pesquisas apontam, contudo, que essa diversidade vem sendo diminuída ao longo dos anos devido à disseminação da forrageira exótica popularmente conhecida como capim-annoni. Somados à isso, eventos de queimadas e pastejo intensivo também contribuem para sua destruição. Um dos fatores importantes na retomada das espécies nativas é o mapeamento das regiões infestadas para planejamento de ações de combate. Visando contribuir esforços, este trabalho promove um estudo a fim de investigar a performance de descritores de textura aplicados no reconhecimento de imagens de forrageiras comumente encontradas no Pampa. Foram utilizadas imagens obtidas de forma manual e também por meio de uso de VANT nas faixas do espectro visível e infravermelho próximo. Dentre as técnicas empregadas para extração de características, destaca-se a Volumetric Bouligand-Minkowski. Trata-se de um descritor baseado em um modelo fractal, aplicado com sucesso em vários cenários. Os resultados mostraram que este modelo pode ser eficaz em determinadas circunstâncias, podendo atingir acurácia de até 99,6%. Em outros cenários, porém, métodos clássicos como os descritores GLCM e LBP apresentaram resultados superiores. Por fim, vale destacar que são analisados os comportamentos de determinadas técnicas diretamente em um processo de segmentação, ratificando, assim, o quão eficazes podem ser tais descritores. / The Pampa biome is one of the most diverse biomes in species of grasses in the world. However, some studies point out that diversity has declined over the years due to the spread of an exotic grass, popularly known as annoni grass. In addition, fires and intensive grazing events also contribute to its destruction. One important action that may contribute to recover native species is the mapping of infested regions so that planning can be devised to combat the annoni grass. This work proposes a study to investigate the performance of texture descriptors applied to recognition of images containing species commonly found in Pampa. We have employed not only manual images, but also UAV in the visible and near-infrared spectrum. Among the techniques used to extract characteristics, Volumetic Bouligand-Minkowski stands out. This descriptor is based on Fractal theory and has been successfully applied to many fields. The results have shown that this model can be effective in certain circumstances, and can reach up to 99.6% accuracy. However, classic methods such the descriptors GLCM and LBP presented better results in other cases. Finally, it is worth mentioning that the behavior of certain techniques are analyzed directly in a segmentation process, thus corroborating how effective these descriptors can be.

<p>Studies in tropical regions have shown that trees and grasses respond differently to fire, grazing and browsing. In African savannas, the responses to fire, grazing and browsing are different, determined by negative or positive correlations. Browsing may have other consequences than grazing because instead of increasing woody biomass it reduces it, causing increase in grass growth, leading to increase in fuel that results in more intense fires and decrease in woody biomass. Fire and herbivory are an important interactive disturbance factors affecting vegetation succession and the tree-grass dynamics in savanna environment. Several of the fire-herbivory interactions are landscape level effects, which is shown in 2 models. My hypothesis is that the tree-grass balances are determined by interactions of both grazing and fire. There have come new scientific data about fire and herbivory and the interaction effects on tree-grass dynamic and succession in the savanna. By analyzing my hypothesis through a comparison between hypotheses, Intermediate disturbance hypothesis, Janzen-Connell hypothesis and the Huston hypothesis, I propose several scenarios of the savanna tree-grass dynamics in East Africa, as a result of this comparison.</p>

Pennisetum Rich, is one of the most important genera in the family Poaceae because it includes forage and crop species such as Pennisetum purpureum Schumach. and Pennisetum glaucum (L.) R. Br. Both P. purpureum and P. glaucum have a number of cultivars and varieties arising due to natural crossing which are very difficult to distinguish morphologically. P. purpureum and P. glaucum also hybridize naturally because they are protogynous and cross pollinated. The resulting hybrids are highly sterile and resemble P. purpureum. Lepidopteran stem borers cause great yield loss in maize produced by resource-poor farmers in Africa and are managed by habitat management or push-pull strategies, in which P. purpureum cultivars and hybrids are used as a trap crop. The aims of this project were to genotype different P. purpureum cultivars and hybrids using Amplified Fragment Length Polymorphism (AFLP) as well as Random Amplified Polymorphic DNA (RAPD) in order to identify cultivars and hybrids and possible misidentifications, assess the congruency of results between AFLPs and RAPDs and to attempt to relate these results to the oviposition preference of Chilo partellus for different P. purpureum cultivars. The individuals to be fingerprinted were collected from several countries in sub-Saharan Africa, a few from the USA and one from China. The AFLP analysis of these individuals were done with primer combinations EcoRI/MseI and Mlul/Msel on polyacrylamide gels and an ABI 3130 xl Genetic Analyzer respectively. The automated sequencer visualized more bands than the polyacrylamide gels. The RAPD technology was not developed any further after 17 primers were tested and no polymorphic bands detected. Overall results indicated that cultivars did not cluster according to geographical origin, and cultivars known by popular names did not always cluster together, indicating diversity within the cultivar or misidentifications. An example of a misidentification is the cultivar Green Gold being no other than cultivar Harare, or cultivar Swaziland 3 being cultivar Sanitas. Proper management by nursery managers cannot be stressed enough, as this will prevent plants getting mixed up, causing confusion. There was no relationship between the relatedness of cultivars and moth oviposition preference. The AFLP technology could be a powerful tool for the DNA fingerprinting and molecular characterization of this grass species, but poor germ plasm management negates its application. / Thesis (M. Environmental Science)--North-West University, Potchefstroom Campus, 2008.

Kura clover (Trifolium ambiguum) is a perennial legume species that has been found to have exceptional persistence in the United States, Australia and New Zealand. There are two challenges that impede the incorporation of Kura clover into pasture mixtures in Alberta. The first is the lack of available seed, and the second is poor establishment success in mixtures with highly competitive grass species. A series of experiments were conducted to (i) address the potential for seed production in a central Alberta environment and (ii) to determine alternative strategies for establishment in mixtures. Kura clover successfully flowered and produced seed under central Alberta growing conditions. Seed production was greater from the cultivar Endura than Cossack. Kura clover seed production was not affected by row spacing however, yield was greater when clover was planted at 3 or 6 kg/ha versus 9 or 12 kg/ha. Seed yield ranged from 80 kg/ha to 350 kg/ha. Establishing Kura clover with a cover crop reduced flowering and seed production. Corn (Zea mays) was the least competitive cover crop, followed by faba bean (Vicia faba L.). Canola (Brassica napus), peas (Pisum sativum L.), barley (Hordeum vulgare) and triticale (X Tritosecale) reduced Kura clover seed yield and are not recommended as cover crops. Comparison of above and below ground competition between Kura clover and meadow bromegrass (Bromus biebersteinii), indicated that below ground competition has the greatest impact on Kura clover seedling growth. Altering seeding rate and delaying introduction of the grass species by up to two months significantly improved Kura clover establishment in mixtures. Kura clover survival in established pastures was higher with physical than chemical sod suppression of the standing forage. Dry matter yield of Kura clover was greatest when defoliated at 6 week intervals. Challenges still remain regarding seed production and establishment of Kura clover. However, we successfully addressed the major concerns regarding the potential of Kura clover in Alberta. / Plant Science