In order to determine if weed control as practised during the establishment phase of tree growth had a beneficial and long term (over a six to eight year rotation) impact on tree performance, a Eucalyptus hybrid clone (GC304) was planted in a field trial in 1990. The trial was situated in the coastal Zululand region near the KwaZulu-Natal town of Mtunzini. Nine different vegetation management treatments were imposed from establishment. These included a weedy control, a manually weeded treatment, a chemically weeded treatment, a 1.2 m row and 1.2 m inter-row weeding, a 0.5 m radius ring weeding, a complete weeding except for a 0.5 m radius ring around the tree, and the use of two legume cover-crops, Mucuna puriens (cowpea) and Vigna sinensis (velvet bean). Initial improvements in tree performance from these competition control treatments were detected from 60 days after planting, and were maintained over seven growing seasons. This occurred despite the absence of competitive vegetation after the first growing season due to reduced light, following crown canopy closure. There were strong indications that initial competition was mainly for moisture and possibly also for nutrients, rather than competition for light. Initially those trees that had weeds within their immediate vicinity were most affected (weedy control, inter-row weeding and the complete weeding except for a 0.5 m radius around the tree). With time, tree performance was more closely related to an increase in the percentage of the area kept free of weeds. The best performing treatment at felling, the manually weeded control, produced 17.1 % and 38.5 % more merchantable timber than the 1.2 m row weeding and the weedy control, at an increased profit of 8 % and 27 %, respectively. Two forms of competition (interspecific and intraspecific competition) were evident in the weedy control at different stages of tree development in contrast to the one (intraspecific competition) in the manually weeded treatment. Interspecific competition resulted in greater variability between the trees in the weedy control by the time canopy closure had occurred. This differentiation in tree size was further enhanced by asymmetric intraspecific competition once the trees had become established. The onset of intraspecific competition was first detected 995 days after planting for the manually weeded treatment and 1641 days after planting for the weedy control. Of the various competition indices that were tested in order to try and explain this differential growth in terms of individual tree performance, none was able to do so to complete satisfaction. The growth rates of different tree size classes were therefore compared for the weedy control and manually weeded treatment. The diverging slopes of the different stem area classes indicated that the larger trees were growing at the expense of the smaller trees. This type of competition is known as asymmetric intraspecific competition. In addition, a comparison was made between the slopes for the weedy and weedfree treatments for similar stem area classes. No significant difference was detected, indicating that similar size classes in these two treatments grew at similar rates. Trees from three treatments were selected (manually weeded treatment, 1.2 m row weeding treatment and the weedy control) and tested for the wood and pulping properties of density, active alkali consumption, extractable content, screened pulp yield, pulp yield per hectare and fibre length and coarseness. The use of Canonical Variate Analysis to determine if there were differences between the three treatments for the variates measured, indicated that they were significantly different. There was a significantly positive trend of an increase in density, extractable content and active alkali consumption with increased weed control. A possible explanation for this could be that the larger trees of the manually weeded treatment were under more stress (from increased intraspecific competition) during the latter phase of their growth. This was demonstrated by comparing the growth rates for these three treatments. The smaller trees of the 1.2 m row weeding treatment and the weedy control exhibited a lower rate of decline. As no significant difference was detected for screened pulp yield between the treatments, any differences in the pulp yield per hectare values could be attributed to differences in the merchantable volume. There was a 22.6 % and 40.8 % increase in the pulp yield per hectare for the manually weeded treatment in comparison to the 1.2 m row weeding treatment and the weedy control. The planting of cover-crops, although beneficial in terms of weed suppression, caused significant tree suppression. This occurred despite the fact that their initial biomass accumulation was slower than that of the natural weed population. Of the two cover-crops, the use of the velvet bean was not considered suitable due to its vigorous vining habit which affected the growth form of the trees. Subsequent work suggests that if the beneficial qualities of cowpeas are to be realised (that of weed suppression, erosion control and nitrogen fixation), a delay in their planting by three months after establishment of the trees should alleviate any negative impacts on tree growth. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1999.

The genus Eucalyptus has been planted extensively throughout the world in tropical and subtropical regions, primarily because of its economic importance and use in wood and pulp production. Due to the growing demands for timber, forestry companies need to increase the productivity of available forest land. The genetic improvement of forest trees through selection and breeding involves a lengthy process of scientifically controlled trials focused on short-term and long-term goals using breeding and production populations. This investigation focused on the use of Best Linear Prediction (BLP) and its application to: (1) the prediction of genetic gains for a breeding population and, (2) the selection of superior individuals for clonal production of E. grandis. A CSIR dataset for a 20-year-old progeny trial involving 90 open-pollinated families was obtained. Four traits, namely, diameter at breast height (DBH), stem form, splitting and density were identified for use in this investigation. Relevant data were extracted and a file termed, Dataset created. Dataset was edited, standardized and corrected for the fixed effect of replication using SAS® procedures. Precise and accurate population parameter estimates are fundamental in determining breeding strategies and thus, heritabilities of each trait and phenotypic correlations between traits in Dataset were estimated using SAS® procedures. DBH was found to have the highest heritability (0.600), followed by density (0.492). The estimated heritability for stem form was 0.401 and splitting had the lowest heritability at 0.214. A high positive phenotypic correlation of 0.83 was estimated between DBH and stem form. The phenotypic correlations between other traits were close to zero. An index provides a weighted score for individuals, which takes all relevant information into account and allows individuals or families to be chosen for breeding and production purposes. Consequently, Best Linear Prediction (BLP) of individual breeding values were calculated using MATGEN® (2003). Thereafter, BLP values were used to determine the rankings of individual trees for 15 different selection indices. In order to determine the effect of selection on the change in the population mean of a trait, the breeding population's response to selection was predicted and compared across three selection strategies, namely: (1) individual selection, (2) single-trait index selection, and (3) multiple-trait index selection. The top 8% of individuals in the breeding population were selected for and the genetic gains were predicted. It was found that the response to selection was greatest when using individual selection. Furthermore, DBH had the best selection response for all three strategies as compared to the other traits under investigation. Fifteen indices, considering different numbers and choice of traits, were compared for commonality among rankings of the top 30 individuals. Two methods, namely, (1) a rank-correlation matrix and (2) a manual assessment, were used. The commonality between indices showed that a simple index, considering two traits (DBH and density) was equally effective (93%) in identifying genetically-superior individuals as the more complex index that considered four traits. Furthermore, it was possible to select for only three traits (DBH, splitting, density) and identify the same top 30 individuals as using the index that considered four traits. The researcher's goal was to find the most desirable individuals in the population to be used for production purposes, such as clonal forestry. Consequently, various selection options, specifying certain trait requirements, were used to select superior individuals for use in production and deployment. The "commercial selection" option was the only option successful in obtaining an individual that met the required criteria for the four traits in the population of 475 individuals. The results suggested that breeders should consider large populations and only a few important traits in order to obtain a greater number of individuals suitable for mass propagation in clonal forestry. In order to further investigate the effect of population size on the number of individuals suitable for clonal forestry, a hypothetical population was generated. This was accomplished using between family and within family standard deviation values obtained from Dataset. The large hypothetical population of 1000 individuals produced twelve individuals suitable for production purposes, as opposed to only one in the real population of 475 individuals. This result further indicates that a larger population provides a greater number of individuals appropriate for use in production and deployment. This investigation successfully addressed the aims by: (1) calculating individual breeding values (BLP) and ranking individuals, (2) predicting the breeding population's response to selection, according to three strategies, for the four traits under investigation, and (3) identifying superior individuals for use in commercial clonal forestry. As the work of tree breeders is aimed at improving the growth and quality of trees by increasing the frequency of desirable genotypes in the population, further research could focus on (1) the effect of different sets of economic weightings on index rankings in a population and (2) the influence that population structure has on the optimal genetic gains obtained. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2006.

Made available in DSpace on 2014-06-11T19:24:41Z (GMT). No. of bitstreams: 0 Previous issue date: 2004-08-25Bitstream added on 2014-06-13T19:52:19Z : No. of bitstreams: 1 calonego_fw_me_botfca.pdf: 1047073 bytes, checksum: 21280f1c5afee5c936363dd679a08263 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Universidade Estadual Paulista (UNESP) / The present study to have to do as aim to determine the log steaming time its involvement on the sawing process and on the drying of Eucalyptus grandis wood. In order to do it so, were used logs with diameter of 20 at <25, 25 at <30 and 30 at <35 cm, from the Horto Florestal, Manduri, São Paulo. The logs were heated during 20 hours at 90ºC of temperature and 100% of relative humidity. For the adaptation of the logs heating general model developed by Steinhagen to make use of thermocouples fixed it logs center and a datalogger recorded the time and real temperature at each minute. Later the logs were sawing for width tangential system and measuring of the defects resulted from the growth stress were performed with intention to evaluate the effect of steaming treatment and the growth stress behavior with logs diameters. The sawn wood was dry in the dry-kiln and were available the dry defects of the sawn wood deriving as much the control logs as the steamed logs. The results indicate that: the log steaming time determination general model developed by Steinhagen don't is applied for eucalypts and that are necessary the use of the adjustment factors that provided the used them model for studied kind; the logs steaming provided the release of a great part of the growth stress, without, however, eliminate them completely, showing, nevertheless, that this treatment to be feasible and advisable for the growth stress relief; there are among the boards a difference on the growth stress magnitude with the logs diameters showing that the bigger logs to produce boards to be inclined cracks and that logs with diameter smaller to develop biggest boards opening during the sawing process; across of the drying schedules used so much boards provided of the control logs as the heated logs don't to presented collapse e that the warping and end checks were smaller in the heated material; the boards provided... (Complete abstract click electronic access below)

Made available in DSpace on 2015-03-26T13:53:33Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1136366 bytes, checksum: 78962870de2c0891b84e47ea7889faea (MD5) Previous issue date: 2013-07-31 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In Brazil, eucalyptus have been planted under different climatic and edaphic conditions. As regard to climate, the plantations have been located in a wide range of conditions, from regions with no restrictions to regions with strong water deficit. Similarly, soils are quite variable in terms of fertility and physical characteristics. The combination of soil and water restrictions can be overcome by the selection of genetic material adapted to such conditions. Soil low fertility can easily be resolved by mineral fertilization, whereas climatic and soil physical restrictions are of more difficult solution. Selecting genotypes adapted to such restrictions has been one of the alternatives adopted in the Brazilian silviculture. Early selection attributes, as biomarkers of such adaptations, including morphological, anatomical and physiological characteristics, are of great practical interest. The objective of this study was to evaluate characteristics and morpho-anatomic adaptations of eucalypt clones, differing in tolerance to water deficit and relate these adaptations to isotopic carbon discrimination (13CO2 (&#61508;)). The study was carried out in commercial eucalypt stands located in two different climate conditions (mean of 900 mm and 1,500 mm per year) on an soil Yellow Ultisol, in the Northeast of Bahia State, Brazil. In both sites, three clones (1277, a hybrid of Eucalyptus urophylla x E. camaldulensis, 1404, E. urophylla, and 1407, a hybrid of E. urophylla x E. grandis) respectively considered of high, medium and low tolerance to water deficit, were planted at 3 x 3 m spacing and the stands were approximately 5 year old at the assessment time. In each site were selected and felled four trees of average size (diameter and height) per clone. At the stem base, a disc of 5 cm width was removed for 13 CO2 (&#61508;) determination. Wood samples were collected from each disc in radial sections, dried in the laboratory and submitted to a mass spectrometer. Ten completely expanded and active leaves of the third or fourth worl of branches located at the top, half and base of the crown were also collected from each sampled tree for morphometric analyses and dimension determination (area, width, length and perimeter). An additional leaf was also collected for micrimorphometric analyses (cuticle, epidermis and mesophyll width and intercellular space). In the region of lower precipitation, clone 1277 presented higher &#916;13C, lower leaf area at the top of the crown, lower water diffusion time of leaves at the half and bottom of the crown and less mesophyll intercellular space than the other two clones. All these characteristics are indicators of adaptation to xeromorphic conditions. Therefore, quantitative and qualitative characteristics were associated with the tolerance to water restrictions. Xeric characteristics were more evident on clone 1277, which showed higher tolerance and adaptation to conditions where water restrictions predominate. / O cultivo do eucalipto no Brasil tem ocorrido em diferentes condições edafoclimáticas. Quanto ao clima, os plantios têm sido feitos desde regiões onde não ocorrem déficits até regiões com fortes restrições hídricas. De modo semelhante, há plantios em solos com restrições variáveis quanto à fertilidade e, ou, características físicas. A combinação de tais restrições requer a seleção de material genético que possa suplantá-las. Enquanto a baixa fertilidade do solo pode ser contornada pela técnica de fertilização, a restrição física e climática é de mais difícil solução. A escolha de genótipos tolerantes ao déficit hídrico tem sido a principal opção para plantio em tais condições. Por isso, a definição de biomarcadores dessa tolerância, como alterações morfológicas, anatômicas e fisiológicas, é de alto interesse prático. O objetivo deste estudo foi avaliar características e adaptações morfoanatômicas em clones de eucalipto com tolerância diferencial ao déficit hídrico e sua relação com a discriminação isotópica do 13CO2 (&#61508;). O estudo foi conduzido em plantios comerciais de eucaliptos situados em duas condições edafoclimáticas no norte do estado da Bahia. As árvores tinham, aproximadamente, cinco anos de idade, no espaçamento inicial de 9 m2 por planta, e os plantios se situam em áreas com precipitação média anual de 900 mm e 1500 mm. Em cada área, os clones 1277 (híbrido de E. urophylla x E. camaldulensis), 1404 (E. urophylla) e 1407 (híbrido de E. urophylla x E. grandis), considerados com alta, média e baixa tolerância à seca, respectivamente, foram selecionados em talhões situados em Argissolos Amarelo para avaliações biométricas e fisiológicas. Foram selecionadas e abatidas quatro árvores médias por clone e área e, na base de cada uma, foi retirado um disco do tronco com, aproximadamente, 5 cm de espessura, do qual foram obtidas amostras das seções radiais do lenho para determinação dos isótopos do C. De cada árvore foram, ainda, selecionadas folhas completamente expandidas do terceiro ou quarto nó do ápice para a base do ramo, em três posições distintas da copa: basal, mediana e apical. Foram coletadas dez folhas para cada uma dessas posições as quais foram utilizadas nas análises morfométricas para obtenção da área, largura, comprimento e perímetro. Adicionalmente, uma folha sadia e completamente expandida foi também coletada de cada árvore para as seguintes análises micromorfométricas, em secção transversal: (espessura total, da cutícula, da epiderme e do mesofilo, bem como porcentagem de espaços intercelulares). As características avaliadas foram comparadas pelo teste t a 5% de probabilidade. O clone 1277, mais tolerante à seca, na área com precipitação média anual de 900 mm, mostrou maior &#916;13C em comparação com os demais clones, possivelmente, devido à manutenção da condutância estomática. O clone tolerante (1277), na área com precipitação média anual de 900 mm, apresentou menor área foliar nas folhas do ápice da copa, menor tempo de difusão do vapor de água nas posições basal e mediana, e menores porcentagens de espaço intercelular no mesofilo em todas as posições da copa, características indicadoras de xeromorfismo. Portanto, foram verificadas características qualitativas e quantitativas associadas à tolerância dos clones ao déficit hídrico. As características xeromórficas mais evidentes do clone 1277 lhe conferem maior tolerância e condições de se adaptar e desenvolver sob restrição hídrica.

Orientador: Elias Taylor Durgante Severo / Banca: Claudio Angeli Sansígolo / Banca: Geraldo Bortoletto Junior / Abstract: The present study to have to do as aim to determine the log steaming time its involvement on the sawing process and on the drying of Eucalyptus grandis wood. In order to do it so, were used logs with diameter of 20 at <25, 25 at <30 and 30 at <35 cm, from the Horto Florestal, Manduri, São Paulo. The logs were heated during 20 hours at 90ºC of temperature and 100% of relative humidity. For the adaptation of the logs heating general model developed by Steinhagen to make use of thermocouples fixed it logs center and a datalogger recorded the time and real temperature at each minute. Later the logs were sawing for width tangential system and measuring of the defects resulted from the growth stress were performed with intention to evaluate the effect of steaming treatment and the growth stress behavior with logs diameters. The sawn wood was dry in the dry-kiln and were available the dry defects of the sawn wood deriving as much the control logs as the steamed logs. The results indicate that: the log steaming time determination general model developed by Steinhagen don't is applied for eucalypts and that are necessary the use of the adjustment factors that provided the used them model for studied kind; the logs steaming provided the release of a great part of the growth stress, without, however, eliminate them completely, showing, nevertheless, that this treatment to be feasible and advisable for the growth stress relief; there are among the boards a difference on the growth stress magnitude with the logs diameters showing that the bigger logs to produce boards to be inclined cracks and that logs with diameter smaller to develop biggest boards opening during the sawing process; across of the drying schedules used so much boards provided of the control logs as the heated logs don't to presented collapse e that the warping and end checks were smaller in the heated material; the boards provided... (Complete abstract click electronic access below) / Mestre

Submitted by Reginaldo Soares de Freitas (reginaldo.freitas@ufv.br) on 2017-02-15T16:44:38Z No. of bitstreams: 1 texto completo.pdf: 2717053 bytes, checksum: 3c55e425d0ace7c2fad945c8a704e310 (MD5) / Made available in DSpace on 2017-02-15T16:44:38Z (GMT). No. of bitstreams: 1 texto completo.pdf: 2717053 bytes, checksum: 3c55e425d0ace7c2fad945c8a704e310 (MD5) Previous issue date: 2005-02-22 / O crescimento e a dinâmica de copa foram avaliados em plantas de clone de Eucalyptus grandis submetidas a diferentes tratamentos de desrama artificial e desbaste, em Abaeté, MG. Foram utilizadas combinações de diferentes intensidades de desrama (altura de remoção dos galhos a partir do solo), freqüências (número de intervenções necessárias para atingir 6 m de altura livre de galhos) e idade de aplicação da primeira intervenção de desrama (16, 20 e 28 meses de idade). Aos 55 meses de idade, procedeu-se o desbaste, eliminando 35% do número total de árvores em cada parcela do experimento. A fim de comparar o comportamento das árvores em área desbastada e não desbastada, foi realizada uma simulação de desbaste em área não desbastada, selecionando o mesmo número de árvores que seriam eliminadas, caso o desbaste tivesse ocorrido. O índice de área foliar (IAF) apresentou valor médio de 2,75, aos 55 meses de idade, reduzindo para 1,98, logo após a realização do desbaste. Devido à recomposição foliar, seis meses depois, o IAF aumentou para 2,99 e, aos 68 meses, para 3,11, na área desbastada. Aos 68 meses de idade, o IAF na área não desbastada foi 22,64 % mais elevado na área desbastada. A transmissividade da radiação fotossinteticamente ativa (t%) aumentou de 11,96% para 22,73%, logo após o desbaste (55 meses) e, aos 68 meses, reduziu para 16,76%, devido à recomposição foliar das plantas. Aos 68 meses de idade, em área não desbastada, t% foi de 9,55 %, significativamente inferior ao observado em área desbastada. O índice de cobertura vegeta (IC), aos 55 meses de idade, reduziu de 0,83 para 0,69, após a realização do desbaste. Aos 68 meses de idade, o IC foi de 0,70, ou seja, este método foi menos sensível às mudanças do desenvolvimento da copa, comparativamente ao método utilizando o IAF e t%. Aos 68 meses de idade, foi observada grande quantidade de galhos médios e grossos em árvores não desramadas até a altura de 6 m, demonstrando a importância da aplicação de desrama artificial, pois estes galhos são os responsáveis pela presença de nós na madeira. Nesta idade, as plantas da área desbastada apresentaram maior quantidade de folhas e galhos vivos em estratos mais baixos da copa do que na área não desbastada, em razão da maior competição na área desbastada. A quantidade de manta orgânica acumulada no solo, aos 55 meses de idade, foi 5,48, 3,37 e 0,50 t/ha, e, aos 68 meses de idade, foi 5,23, 4,64 e 1,26 t/ha de folha, galho e casca, respectivamente. Aos 68 meses de idade, não foi verificada diferença signifi- cativa, ao nível de 5% de probabilidade, entre os tratamentos de desrama artificial, para o crescimento em altura, diâmetro e volume, independentemente da idade de aplicação da primeira intervenção de desrama. Nesta idade, o crescimento diamétrico das árvores remanescentes em área desbastada foi superior ao das plantas superiores, em área não desbastada. Aos 55 e 68 meses de idade houve maior proporção de árvores com maior diâmetro nas parcelas que receberam a primeira intervenção de desrama aos 20 meses de idade. Em resumo, verificou-se que a desrama artificial utilizada não afetou negativamente o crescimento das plantas do clone estudado, porém, deve ser realizada o mais cedo possível para obter maior produção de madeira limpa. Também, foi observado que este clone apresenta elevada capacidade de recomposição da copa um ano após desbaste, indicando que as árvores remanescentes deverão apresentar elevada taxa de crescimento em diâmetro. / Growth and crown dynamics of an Eucalyptus grandis clone, submitted to artificial pruning and thinning, were studied in Abaeté, MG, Brazil (latitude 19o16’34”S and longitude 45o44’56”W). Plants were submitted to various combinations of pruning intensities (height from the ground for branch removal) frequencies (number of interventions needed to reach 6 m height free of branches), and age of the first intervention (16, 20 and 28 months-old). At the age of 55 months, thinning was applied by removing 35% of the total number of trees in each plot of the experiment. Leaf area index (LAI) decreased from 2.75 to 1.98 immediately after thinning. A significant LAI recovery was verified six months after thinning, when reached 2.99, increasing up to 3.11 at the age of 68 months. The LAI of the non thinned forest was 22.6% higher than that of the thinned forest, at the age of 68 months. This indicates the capacity of remnant trees after thinning to keep expanding their crown. Photosynthetic active radiation transmissivity (t%) increased from 11.9 to 22.7%, shortly after thinning, and, at the age of 68 months, it reduced to 16.8%, due to leaf recover. In the non thinned forest, transmissivity was 9.6%, which is significantly smaller than in the thinned forest. The vegetation cover index obtained from digital photographs, at the age of 55 months, reduced significantly with thinning, from 0.83 to 0.69, and, at the age of 68 months, it was only 0.70, showing that this method was less sensitive to crown dynamic, if compared to the method using the LAI and t%. By the age of 68 months, a great quantity of medium and large branches was observed on trees which were not pruned up to the height of 6 m from the soil, showing the importance of the artificial pruning. These branches are responsible for the presence of knots in the sawn boards. At this age, the plants in the thinned forest showed a greater quantity of leaves and live branches in the lower strata than those in the non thinned forest, due to the higher competition in the non thinned forest. Litter accumulation, at the age of 55 months, was of 5.48, 3.37 and 0.50 ton/ha of leaves, branches and bark, respectively. No significant differences, at 5% probability, were observed between the artificial pruning treatments, for the growth in height, diameter and volume, independently of the age of the first pruning intervention, up to 68 months. At this age, the growth in diameter of the remaining (superior) trees in the thinned forest was slightly higher than for the superior trees in the non thinned forest. At 55 and 68 months of age, it was observed a greater proportion of larger trees in the plots that received the first pruning intervention at the age of 20 months, as compared to those pruned at 16 and 28 months. The overall results indicated that pruning treatment applied to this clone had no detrimental effect on plant growth. Therefore, it should be applied as early as possible to produce larger extension of clear wood. Also, based on the crown recovery of the clone studied, one year after thinning, it can be expected that the remnant tree will present higher diameter growth rate. / Não foi localizado o cpf do autor.

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Dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science. School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg, South Africa / In the forestry industry the requirement for the maintenance of a broad genetic base is integral to the success of breeding programmes such as those for Eucalyptus grandis, an important species to the South African forestry industry. Plant cryopreservation is an economical option to maintain such a genetic base, as it allows storage of vegetative materials at sub-zero temperatures, while maintaining juvenility. However, successful cryopreservation of this sub-tropical species has been restricted by its sensitivity to cryopreparative drying. As a consequence, the viability of material is reduced even before reaching the freezing stage. Despite this abiotic stress restriction, evidence of upstream ‘cross-talk’ implying downstream ‘cross-tolerance’ has suggested the possibility that cold acclimation may improve the tolerance responses towards dehydration stress by means of ‘cross-acclimation’. It was therefore the aim of the study to understand some of the physiological and biochemical responses of in vitro E. grandis shoots to different non-freezing low (chilling) temperatures and exposure periods, and to establish an appropriate ‘cross-acclimation’ regime for the physical drying pre-treatment. E. grandis shoot clusters (4-8 leaves and 2-5 axillary buds) were exposed to the chilling temperatures of 5°C, 10°C or 15°C for 1 or 3 days. The physiological and biochemical responses were evaluated, and thereafter the appropriate cold acclimation (or ‘cross-acclimation’) regime selected. The appropriate physical drying time was also selected for shoot clusters according to their physiological responses. When the appropriate regimes had been determined, the physiological and biochemical responses of shoot clusters treated consecutively to cold acclimation and then physical drying were evaluated. The physiological responses evaluated were water content, viability, and vigour (i.e. the number of visible axillary buds and shoots produced over 2 weeks). The biochemical responses measured were the concentrations of: 1) total soluble sugars, 2) starch, 3) phenolic acid, and 4) superoxide. The data suggested that the appropriate cold acclimation regime was treatment at 10°C for 3 days. This was based on the accumulation of the high levels of phenolic acid (3.05 ± 0.09 mg GAE.g-1 FWS) and positive vigour responses (11.90 ± 0.60 visible axillary buds/week and 3.10 ± 0.20 visible shoots/week), compared with the other chilling temperature treatments. The appropriate drying time selected for shoot clusters was 80 min over activated silica gel to achieve a water content of 0.32 ± 0.04 g water.g-1 FWS. In the dried material there were high levels of soluble sugars (47.65 ± 1.90% of the fresh weight of shoots) and unknown components that accounted for 48.10 ± 1.86% of the fresh weight, followed by phenolic acid (3.09 ± 0.05%) and proline (0.490 ± 0.011%). Despite these measured responses, viability of the shoots was impacted by drying, dropping to 88.9 ± 3.9%. When shoot clusters were pre-treated at 10°C for 3 days and then physically dried, viability of all (100%) the material was retained and the water content did not drop as low as with physical drying alone, dropping to 0.52 ± 0.05 g water.g-1 FWS. The biochemical responses showed that tolerance was strongly dependent on a high proportion of soluble sugars (83.66 ± 1.48% of the fresh weight of shoots) and phenolic acid (3.77 ± 0.12%), followed by proline (0.406 ± 0.018%). The study had confirmed that ‘cross-acclimation’ through means of cold acclimation (chilling pre-treatment at 10°C for 3 days) can induce ‘cross-tolerance’ towards physical drying, where osmotic adjustments and osmoprotection appeared to have been improved. It is therefore possible that this may have the potential to improve survival during the latter stages of the cryopreservation procedure, despite the higher retention of water in shoot clusters after drying.

Este trabalho trata dos aspectos geográficos e históricos dos eucaliptos, na Austrália e no Brasil, com atenção especial para a situação no Vale do Paraíba, estado de São Paulo. O trabalho possui três capítulos, nos quais são tratados temas pertinentes à questão dos eucaliptos no Brasil. Existem diferentes tipos de plantios de eucaliptos, em áreas urbanas e rurais, com finalidades comerciais e não-comerciais. Focou-se principalmente os extensos plantios em áreas rurais, com finalidade comercial. Os resultados das medições e informações coletadas demonstram que no Vale do Paraíba paulista ocorrem impactos ambientais positivos e negativos a partir do cultivo de eucaliptos, exigindo medidas para minimizar os impactos negativos e recuperar as áreas rurais da região. / This work deals of geographics and historic aspects of eucalyptus, in Australia and Brazil, with particular emphasis for the situation in the region of Vale do Paraíba, São Paulo state. The work have three chapters, where are treated the relevant themes related to the eucalyptus in Brazil. There are different types of eucalyptus plantations, in urban and rural areas, for commercial and not commercial purposes. Focused mainly the extensive plantations in rural areas, for commercial purposes. The results of the measures and informations collected show that in the Vale do Paraíba region, occurring positive and negative environmental impacts, from the cultivation of eucalyptus, requiring measures to minimize negative impacts and recover the rural areas of the Region.

Os óleos essenciais são metabólitos secundários extraídos de plantas e apresentam diversas propriedades para fins medicinais. O objetivo deste trabalho foi caracterizar o óleo essencial de folhas secas de E. staigeriana, verificar sua atividade antimicrobiana e antibiofilme frente a bactérias gram-positivas e gram-negativas e avaliar a expressão dos genes de virulência e resistência em Listeria monocytogenes e Enterococcus faecalis resistente a vancomicina (VRE) na ausência e presença de concentração sub-inibitória do óleo essencial, por PCR quantitativo em tempo real (qPCR). A caracterização do óleo foi realizada por cromatografia gasosa acoplada a massa (GC-MS) verificou-se a presença de 21 compostos, sendo os constituintes majoritários o geranial (28,67 %), neral (19,68 %) e limoneno (17,29 %). A ação antimicrobiana foi avaliada e observou-se que o óleo apresentou atividade frente a bactérias gram-positivas, com diâmetros de halos de inibição de 0 a >45 mm. A concentração inibitória mínima (CIM) foi determinada para bactérias gram-positivas, sensíveis e resistentes a agentes antimicrobianos como VRE, e variou de 0,19 a 6,25 %. Ação antibiofilme do óleo foi avaliada tanto na formação, quanto sob um biofilme pré-estabelecido. O óleo essencial apresentou capacidade de inibir a formação do biofilme de todas as cepas testadas, mas pouca ou nenhuma capacidade de remoção do biofilme pré-formado. Na análise de expressão gênica por qPCR para L. monocytogenes, verificou-se que três dos genes de estresse celular (sufS, sod e degU) apresentaram uma diferença significativa na presença do óleo. Para a cepa de E. faecalis VRE, nenhum gene selecionado apresentou alteração na expressão gênica. Como conclusão, este estudo demonstrou que o óleo essencial de folhas secas de E. staigeriana possui atividade antimicrobiana do frente a bactérias gram-positivas e sem atividade em gram-negativas. / Essential oils are secondary metabolites extracted from plants and they have been showing several medicinal properties. The aim of this study was to characterize the essential oil extracted from dry leaf of E. staigeriana, as well as to verify the antimicrobial and anti-biofilm activities against gram-positive and gram-negative bacteria, and to evaluate the expression of virulence and resistance genes in Listeria monocytogenes and Enterococcus faecalis vancomycin resistant (VRE) in the absence and presence of sub-inhibitory concentration of the essential oil by quantitative real time PCR (qPCR). The oil characterization was performed by CG-MS and it was verified the presence of 21 compounds, being the geranial (28.67 %), neral (19.68 %) and limonene (17.29 %) the major compounds. The antimicrobial activity was evaluated and it was observed that the essential oil has effect against gram-positive, with inhibition zone diameter ranges from 0 to 45 mm. The minimum inhibitory concentration (MIC) was determined, to sensible and resistant gram-positive bacteria to antimicrobial agents, such as VRE, and varied between 0.19 to 6.25 %. The anti-biofilm action of the oil was verified on formation, and under a pre-established biofilm. The essential oil showed capacity to inhibit the biofilm formation for all tested strains, but few or no ability to remove the pre-established biofilm. In the analysis of gene expression by qPCR for L. monocytogenes, three cell stress genes (sufS, sod and degU) with significant difference in the presence of the oil. For E. faecalis VRE strain no one of the selected genes showed alteration in the gene expression. In conclusion, this study demonstrates the potential of essential oil from dry leaf of E. staigeriana for future use in the control of gram-positive bacteria.