A survey of the current status of Rhododendron ponticum in the Peak District and Sheffield area was carried out. It was found to be widespread over much of the area, particularly on free-draining, nutrient-poor, acidic soils, in sheltered, moist situations. It was largely absent from the Carboniferous and Magnesian Limestone Series, from the high altitude Kinder/Bleaklow massif and from areas subject to intensive agricultural or industrial development. Disturbance of habitats through forestry, grazing or recreational activity seems to encourage invasion of suitable areas. The role of mycorrhizal infection in R. ponticum was investigated. Mycorrhizal plants had lower Root/Shoot Ratios, higher Relative Growth Rates and showed increased yield compared to non-mycorrhizal plants. The benefits of infection were strongest on nutrient-poor soils without added nutrients. Infection of roots was visible after around six weeks and the effects of mycorrhizas were increasingly apparent during the following six weeks. The source of fungal inoculum was investigated and considered. The 'interference' phenomenon described by earlier workers was investigated. A mixture of competitive and allelopathic influences upon test seedlings in bioassays was demonstrated. The toxicity . found, was closely related to the presence of R. ponticum roots in the soil. Both living or dead roots produced the effects. These were not removed by nutrient addition. Interference was not dependent on mycorrhizal infection of the R. ponticum roots. To help an understanding of the interference demonstrated, a survey was undertaken of the 'free' phenolic compounds occurring in R. ponticum tissues, associated soil and litter, and in canopy throughfall. These compounds have been implicated in allelopathic interactions involving other members of the Ericaceae. R. ponticum tissues were found to have very high concentrations of 'free' phenolic compounds compared to other plant species examined. Considerable variation in form and amount was found with tissue type and age. Phenolic compounds were detected in associated soil and litter, as well as in canopy throughfall from R. ponticum. It was shown that the interference cannot be fully explained by competition for water and/or nutrients. In some situations a toxic influence perhaps due to aromatic and aliphatic acids released from the roots, has a major effect on the interaction between R. ponticum and associated vegetation. Competition for nutrients and/or water clearly occurs in some field situations, particularly when R. ponticum bushes are encroaching on established vegetation. However, with bare-zones (either in the field or under artificial conditions) competition factors may be almost totally eliminated by the toxicity which inhibits root formation. Since the seedlings have very restricted root development, they are barely able to compete for nutrients or moisture, and the toxic effects dominate the interaction. The natural situation in the field is complicated by the acidification of soils associated with R. ponticum, the physical and chemical effects of its litter, shading and the overall influence of the plant on soils and nutrient cycling. The large quantity of 'free' phenolic compounds in R. ponticum tissues (especially new leaves and new stems) probably have anti-herbivore and/or anti-pathogen functions. This would explain the observed lack of damage to the plant by invertebrate herbivores, diseases or parasites. These compounds would thereby enhance the growth and competitive ability of R. ponticum.

Made available in DSpace on 2014-06-12T15:52:55Z (GMT). No. of bitstreams: 2 arquivo5063_1.pdf: 1943609 bytes, checksum: 6d7975c9116af7673b14d0bd5c4b9475 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2003 / Foram caracterizados citogeneticamente oito acessos, incluindo a linhagem de trigo PF 839197 (Triticum aestivum, 2n = 42), Thinopyrum ponticum PF Ag. el. 84001 (2n = 70) e seis acessos híbridos derivados de PF 839197/PF Ag. el. 84001//2* CEP19 , com cinco ou sete gerações de autofecundação. Cromossomos de PF 839197 e de Ag. el. 84001 foram analisados por hibridização in situ com as sondas pTa794, pTa71, pSc119.2, pAs1 e (AAG)5. A linhagem PF 839197 mostrou padrão de marcas semelhante ao da cultivar Chinese Spring , exceto para o braço 1BS de padrão típico de centeio, sugerindo uma translocação 1BL.1RS, confirmada por hibridização genômica in situ (GISH). O acesso PF Ag. el. 84001 apresentou 17 cromossomos com sítios de DNAr 45S e 5S e três cromossomos apenas com DNAr 5S. Os acessos híbridos foram instáveis mitoticamente, observando-se variação numérica extensa, com mosaicismo em 100% dos indivíduos e maior freqüência de números superiores a 42 cromossomos. Essas variações foram confirmadas pela medição do conteúdo de DNA. Em mitose, verificou-se a presença de cromossomos de separação precoce, cromátides retardatárias, fragmentos cromossômicos e micronúcleos, também evidenciada pela imunocoloração com anti-histona H3 fosforilada. Observou-se que nos cromossomos de separação precoce e nas cromátides retardatárias as histonas não fosforilaram. Essa instabilidade pode ter sido herdada da cultivar CEP 19 , que foi relativamente instável. A GISH, utilizando DNA genômico de Th. ponticum, mostrou que o complemento cromossômico de cinco acessos consiste de 36 a 42 cromossomos de trigo e de 11 a 14 de Thinopyrum, sugerindo que estes últimos tendem a ser transmitidos como conjuntos monoplóides nos anfidiplóides parciais

Made available in DSpace on 2014-06-12T15:55:38Z (GMT). No. of bitstreams: 2 arquivo9345_1.pdf: 1943609 bytes, checksum: 6d7975c9116af7673b14d0bd5c4b9475 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2003 / Foram caracterizados citogeneticamente oito acessos, incluindo a linhagem de trigo PF 839197 (Triticum aestivum, 2n = 42), Thinopyrum ponticum PF Ag. el. 84001 (2n = 70) e seis acessos híbridos derivados de PF 839197/PF Ag. el. 84001//2* CEP19 , com cinco ou sete gerações de autofecundação. Cromossomos de PF 839197 e de Ag. el. 84001 foram analisados por hibridização in situ com as sondas pTa794, pTa71, pSc119.2, pAs1 e (AAG)5. A linhagem PF 839197 mostrou padrão de marcas semelhante ao da cultivar Chinese Spring , exceto para o braço 1BS de padrão típico de centeio, sugerindo uma translocação 1BL.1RS, confirmada por hibridização genômica in situ (GISH). O acesso PF Ag. el. 84001 apresentou 17 cromossomos com sítios de DNAr 45S e 5S e três cromossomos apenas com DNAr 5S. Os acessos híbridos foram instáveis mitoticamente, observando-se variação numérica extensa, com mosaicismo em 100% dos indivíduos e maior freqüência de números superiores a 42 cromossomos. Essas variações foram confirmadas pela medição do conteúdo de DNA. Em mitose, verificou-se a presença de cromossomos de separação precoce, cromátides retardatárias, fragmentos cromossômicos e micronúcleos, também evidenciada pela imunocoloração com anti-histona H3 fosforilada. Observou-se que nos cromossomos de separação precoce e nas cromátides retardatárias as histonas não fosforilaram. Essa instabilidade pode ter sido herdada da cultivar CEP 19 , que foi relativamente instável. A GISH, utilizando DNA genômico de Th. ponticum, mostrou que o complemento cromossômico de cinco acessos consiste de 36 a 42 cromossomos de trigo e de 11 a 14 de Thinopyrum, sugerindo que estes últimos tendem a ser transmitidos como conjuntos monoplóides nos anfidiplóides parciais

Made available in DSpace on 2014-06-12T17:20:26Z (GMT). No. of bitstreams: 2 arquivo9348_1.pdf: 548547 bytes, checksum: bf307fe478f3f75642ac66863353f679 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2003 / Foram caracterizados citogeneticamente oito acessos, incluindo a linhagem de trigo PF 839197 (Triticum aestivum, 2n = 42), Thinopyrum ponticum PF Ag. el. 84001 (2n = 70) e seis acessos híbridos derivados de PF 839197/PF Ag. el. 84001//2* CEP19 , com cinco ou sete gerações de autofecundação. Cromossomos de PF 839197 e de Ag. el. 84001 foram analisados por hibridização in situ com as sondas pTa794, pTa71, pSc119.2, pAs1 e (AAG)5. A linhagem PF 839197 mostrou padrão de marcas semelhante ao da cultivar Chinese Spring , exceto para o braço 1BS de padrão típico de centeio, sugerindo uma translocação 1BL.1RS, confirmada por hibridização genômica in situ (GISH). O acesso PF Ag. el. 84001 apresentou 17 cromossomos com sítios de DNAr 45S e 5S e três cromossomos apenas com DNAr 5S. Os acessos híbridos foram instáveis mitoticamente, observando-se variação numérica extensa, com mosaicismo em 100% dos indivíduos e maior freqüência de números superiores a 42 cromossomos. Essas variações foram confirmadas pela medição do conteúdo de DNA. Em mitose, verificou-se a presença de cromossomos de separação precoce, cromátides retardatárias, fragmentos cromossômicos e micronúcleos, também evidenciada pela imunocoloração com anti-histona H3 fosforilada. Observou-se que nos cromossomos de separação precoce e nas cromátides retardatárias as histonas não fosforilaram. Essa instabilidade pode ter sido herdada da cultivar CEP 19 , que foi relativamente instável. A GISH, utilizando DNA genômico de Th. ponticum, mostrou que o complemento cromossômico de cinco acessos consiste de 36 a 42 cromossomos de trigo e de 11 a 14 de Thinopyrum, sugerindo que estes últimos tendem a ser transmitidos como conjuntos monoplóides nos anfidiplóides parciais

Memoria para optar al Título Profesional de Ingeniero Agrónomo. Mención: Producción Animal. / En la Estación Experimental Germán Greve, es posible encontrar Thinopyrum ponticum naturalizada, especie en la cual se realizo un estudio para cuantificar la tasa de recuperación y el valor nutritiva de esta, luego de someterla a tres diferentes alturas y frecuencias de corte. Luego de seleccionar una exclusión en un sector donde destacaba la presencia de la especies, se montaron nueve tratamientos los cuales correspondieron a las combinaciones de las frecuencias de corte de 20, 40 y 80 días y a las alturas de residuo de 8, 16 y 24 cm. Cada tratamiento conto con 10 repeticiones, con un universo total de 90 plantas en estudio. Los resultados mostraron que fue posible obtener mayor producción de materia seca a frecuencias de corte de 80 días, independiente de altura de corte, pero se debe considerar las frecuencias de corte más bajas que podrían llegar a igualar esta producción en una temporada. A pesar de no existir diferencia significativa en las alturas de corte efectuadas, es posible inferir que a alturas más severas es posible obtener mayor producción de materia seca, manteniendo un tiempo adecuado de receso para no provocar un deterioro de la pradera. Dentro de los análisis de valor nutritivo de agropiro, se obtuvo que la proteína bruta fue afectada significativamente por la frecuencia y altura de corte, obteniendo los valores más altos en los manejos en que se dejo una menor altura de residuo. En cambio, la fibra detergente neutro solo se vio afectado por la frecuencia de corte, tendiendo a obtener mayores niveles al someter al pastizal a periodos mas prolongados entre cortes. Debido al desgaste de la pradera en estudio, el corte reiterativo, sobre todo a la menor altura, provoco una muerte progresiva de las plantas, por lo que no fue posible extender el ensayo más tiempo luego del corte realizado a los 80 días. Dadas las características y resultados de este ensayo, Thinopyrum ponticum, es una especie que posee un gran potencial pastoril que es importante desarrollar sobre todo para sectores con condiciones adversas para otras plantas. / In Experiment Station Germán Greve, you might find Thinopyrum ponticum naturalized species in which a study was conducted to quantify the rate of recovery and nutritious value of this, then subjecting it to three different heights and cutoff frequencies. After selecting an exclusion in a sector where the main finding of the species, nine treatments which corresponded to the combinations of the frequencies of 20, 40 and 80 days and residue heights of 8, 16 and 24 cm were mounted. Each treatment had 10 replicates with 90 plants total universe of study. The results showed that it was possible to obtain higher dry matter production at frequencies of 80 days, independent of cutting height, but should be considered frequencies lower court could reach production in a match this season. Despite the absence of significant difference in the heights of cut made, it is possible to infer that a more severe stage is possible to obtain higher dry matter production, maintaining an adequate break time to not cause a deterioration of the meadow. Within the analysis of nutritional value of wheatgrass, it was found that the crude protein was significantly affected by the frequency and cutting height, obtaining higher values in the ways in which a lower height of residue left. Instead, neutral detergent fiber was affected only by the cutoff frequency, tending to get higher levels to submit to pasture to longer periods between cuts. Due to wear prairie study, the repetitive cutting, especially at the lowest height, caused a progressive death of plants, so it was not possible to extend the test no longer a cut made after 80 days. Given the characteristics and results of this trial, Thinopyrum ponticum, is a species that has great potential pastoral development is especially important for areas with adverse conditions for other plants.

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