Made available in DSpace on 2017-07-10T17:37:13Z (GMT). No. of bitstreams: 1 Lucas Guilherme Bulegon.pdf: 2078794 bytes, checksum: ccb242a3255f730bf9153212913cc026 (MD5) Previous issue date: 2016-02-19 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The water deficit causes the plant physiological and biochemical disarray, so is sought ways to reduce these effects and increase the tolerance of plants to water stress. Thus, the present study aimed to evaluate the physiological behavior and biochemical Urochloa ruziziensis inoculated with Azospirillum brasilense via seed and leaf (foliar spray) in conditions induced and controlled water deficit. We used the randomized block design and the treatments, control, inoculation of A. brasilense in seeds, foliar spay application of A. brasilense, combination of seed inoculation and foliar spay application of A. brasilense, segmented into four steps. I - factorial scheme 2x2x13, presence and absence of inoculated seeds, presence and absence of water deficit, and light levels, evaluating gas exchange in moderate drought, severe and rehydration. II - 2x4 factorial scheme, the presence and absence of drought, and the four treatments by assessing daily relative water content, soil moisture and gas exchange. III - was used treatments in drought and irrigated control, being determined, the soluble protein content and the activity of superoxide dismutase, peroxidase (SOD) and catalase, and the contents of chlorophyll a and b, and carotenoid. IV - was the analysis of correlations, track and major components for the plants kept in water restriction and irrigated maintained. The results showed that the use of A. brasilense via seed, makes the culture reach greater photosynthetic activity, less point compensation in severe stress conditions. For water relations, gas exchange and enzyme activity, A. brasilense, inferred positively, especially foliar application, with pronounced effects on stomatal regulation and enzymatic action. By observing the variables linked to maintenance of photosynthesis stood out stomatal conductance (moderate and severe) and SOD (severe). In rehydrating the A. brasilense acted in stomatal and enzymatic regulation, leading to a recovery in order to not harm the plant. It follows that the use of A. brasilense regardless of the form increases the tolerance to water deficit in U. ruziziensis, however foliar application has pronounced effect in relation to the main variables associated with the maintenance of photosynthesis and greater prospect of use / O déficit hídrico causa na planta um descontrole fisiológico e bioquímico, assim busca-se formas para reduzir esses efeitos e aumentar a tolerância das plantas a restrição hídrica. Desta forma, o presente estudo objetivou, avaliar o comportamento fisiológico e bioquímico de Urochloa ruziziensis inoculada com Azospirillum brasilense via semente e foliar, em condições de déficit hídrico induzido e controlado. Utilizou-se o delineamento em blocos casualizados e os tratamentos, controle, inoculação de A. brasilense nas sementes, aplicação foliar de A. brasilense, combinação entre inoculação das sementes e aplicação foliar de A. brasilense, segmentado em quatro etapas. I - Esquema fatorial 2x2x13, presença e ausência da inoculação nas sementes, presença e ausência de déficit hídrico, e níveis de luminosidade, avaliando as trocas gasosas em déficit hídrico moderado, severo e reidratação. II - Esquema fatorial 2x4, a presença e ausência do déficit hídrico, e os quatro tratamentos, avaliando-se diariamente teor relativo de água, umidade do solo e as trocas gasosas. III- Utilizou-se os tratamentos em déficit hídrico e o controle irrigado, determinando-se, o teor de proteínas solúveis e a atividade das enzimas superóxido dismutase, peroxidase (SOD) e catalase, e os teores de clorofila a e b, e carotenoides. IV - consistiu na análise de correlações, trilha e de componentes principais para as plantas mantidas em restrição hídrica e mantidas irrigadas. Os resultados mostraram que o uso de A. brasilense via semente, faz com que a cultura alcance maior atividade fotossintética, com menor ponto de compensação em condições de déficit severo. Para as relações hídricas, trocas gasosas e atividade enzimática, o A. brasilense, inferiu positivamente, se destacando a aplicação foliar, com efeitos pronunciados na regulação estomática e ação enzimática. Ao observar as variáveis ligadas a manutenção da fotossíntese destacou-se a condutância estomática (moderado e severo) e a SOD (severo). Na reidratação o A. brasilense atuou na regulação estomática e enzimática, levando a uma recuperação de forma a não prejudicar a planta. Conclui-se que o uso de A. brasilense independente da forma eleva a tolerância ao déficit hídrico em U. ruziziensis, contudo a aplicação foliar tem efeito pronunciado em relação as principais variáveis ligadas a manutenção da fotossíntese, além de maior perspectiva de uso

Com a continuação do aquecimento global, prevê-se o aumento dos períodos de seca, um dos mais importantes fatores abióticos a afetar o crescimento dos eucaliptos no Brasil. Nessa direção, as práticas silviculturais poderiam adaptar-se para favorecer os mecanismos de adaptação das árvores à seca. Assim, na Estação Experimental de Itatinga, foram avaliados os efeitos da adubação potássica sobre os aspectos produtivos e fisiológicos de um povoamento de Eucalyptus grandis, em primeira rotação, submetido à exclusão parcial de chuva durante trinta meses após o plantio. O dispositivo experimental foi um split plot, com três blocos completos e quatro tratamentos: dois regimes hídricos (100% e 63% das chuvas, com exclusão parcial artificial) e duas doses de K (0 e 4,5 kmol ha-1). A meta foi avaliar a influência da nutrição potássica sobre as características e a atividade fotossintética das folhas. A transpiração foi medida por sensores de fluxo de seiva para estimar a eficiência de transpiração do povoamento. O potencial foliar e as trocas gasosas foliares foram monitorados, enquanto os valores de \'delta\'13C do floema foram medidos, para avaliar o estado hídrico e o funcionamento estomático das árvores, em função da disponibilidade de K e de água. Os resultados mostraram que a adição de K atuou sobre vários mecanismos responsáveis pelo aumento do crescimento e da produção de madeira: aumento da área foliar total e individual, da duração de vida foliar, do tamanho e da turgescência celular foliar, da espessura foliar e dos espaços intercelulares no mesófilo foliar, da capacidade fotossintética, da condutância dos estômatos e do mesófilo, da exportação dos fotoassimilados, produzidos nas folhas-fontes, do fluxo de seiva, da eficiência de transpiração na produção de madeira, pelo aumento da repartição de biomassa nesse compartimento. Folhas com sintomas de deficiência de K mostraram concentrações de nutrientes, espaços intercelulares e atividade fotossintética inferiores, e concentrações de açúcares solúveis superiores, na comparação com o tratamento com K, sugerindo uma ligação entre nutrição, anatomia e fisiologia foliar. Durante o déficit hídrico, o E. grandis mostrou um comportamento isohidrodinâmico, associado ao fechamento estomático, ao ajustamento foliar osmótico, à diminuição na elasticidade das paredes celulares, ao aumento na eficiência de uso da água nas folhas, à diminuição da área foliar total e à rápida absorção da água nas camadas profundas do solo. A partir de aproximadamente 22 meses após o plantio, o estado hídrico das árvores diminuiu: (1) nas parcelas com exclusão parcial de chuva, em relação às parcelas sem exclusão parcial de chuva, e (2) nas parcelas com adição de K, em relação às parcelas sem essa adição. Embora a adição de K melhore as relações hídricas nas folhas, o controle dos movimentos estomáticos e as trocas gasosas foliares, ela agravou o estado hídrico das árvores durante períodos de seca intensa, devido ao maior crescimento e à demanda hídrica. Assim, os efeitos benéficos da adição de K sobre a adaptação à seca das árvores poderiam não contrabalançar o aumento do déficit hídrico durante períodos mais intensos de seca. Em relação às previsões futuras de seca, as empresas florestais, provavelmente, terão de adaptar a fertilização para minimizar a demanda de água e os riscos de mortalidade / Global warming is predicted to exacerbate drought, one of the most important abiotic stress factors affecting eucalypts growth in Brazil. Silvilcultural practices might be adapted to enhance drought adaptation mechanisms of trees. This study examined the effects of K addition on productive and physiological aspects of Eucalyptus grandis stands in first rotation submitted to partial through fall exclusion over thirty months after planting. A large-scale through fall exclusion experiment using a split plot design was conducted with three blocks and four treatments: two water regimes (100% and 63% of through fall with partial artificial exclusion) and two K doses (0 and 4.5 kmol ha-1). The influence of K nutrition on characteristics and photosynthetic activity of leaves was assessed Tree transpiration was measured from sap flow probes to estimate water use efficiency. Foliar water potential and gas exchange were monitored, and phloem \'delta\'13C was measured in order to evaluate tree water status and stomatal regulation depending on K and water availabilities. The results showed that K supply influence various mechanisms responsible for tree growth enhancement: increase in total and individual leaf area, leaf lifespan, cell turgor and cell size due to an increase in turgor, leaf thickness and intercellular spaces, photosynthetic capacity, stomata and mesophyll conductances, photoassimilate export from source leaves and transpiration efficiency for wood production through increase of biomass partitioning to this compartment. Leave with K-deficiency symptoms exhibited lower nutrient concentrations and photosynthetic activity, reduced intercellular spaces, and higher soluble sugar contents compared to healthy leaves, which suggested a strong link between nutrition, leaf anatomy and physiology. The adaptive mechanisms of E. grandis trees to cope with water restriction were an isohydrodynamic behavior associated with stomatal closure, osmotic adjustment, a decrease in wall cell elasticity, an increase in foliar water use efficiency, a decrease in total leaf area and a fast water uptake in very deep soil layers. From approximately 22 months after planting onwards, tree water status was lower: (1) in droughted plots compared to the rain-fed plots and, (2) in K-fertilized plots, compared to the K-unfertilized trees. Although K addition enhanced tree water relations, stomatal control and leaf gas exchange, it exacerbated tree water deficit during severe drought as a result of high water demand throughout tree development. Therefore, the beneficial effects of K supply on tree acclimation to drought may not counterbalance the increase in water deficit during severe water restriction periods compared to the K-unfertilized trees. Regarding future drought previsions, forest managers might have to adapt their fertilization regimes to minimize water demand and risks of mortality

O objetivo do trabalho foi avaliar, por meio de variáveis fisiológicas vegetais como fotossíntese, condutância estomática, transpiração foliar, concentração interna de CO2 e temperatura foliar, o efeito de insetos pragas de diferentes hábitos alimentares em suas plantas hospedeiras. Foram estimados os níveis de dano de um sugador, Orthezia praelonga Douglas, 1891, em limão cravo (Citrus limonia L.), e de Leucoptera coffeella (Guérin-Mènevile, 1842), um mastigador, em mudas de café 'Obatã'. Os ensaios foram realizados em condições ótimas de temperatura, com luz e CO2 saturantes, e diferentes porcentagens de área foliar lesionada, obtidas pela variação do número de insetos por folha, no caso de O. praelonga em limão cravo (de 0 a 35 cochonilhas/folha (0-6%), de 40 a 70 cochonilhas/folha (7-13%), de 80 a 220 cochonilhas/folha (14-40%) e >220 cochonilhas/folha (>40%)) ou por tecido vegetal consumido (intervalos de 0-25%, 26-36% e >37%), no caso de L. coffeella em mudas de cafeeiro. As leituras das variáveis fisiológicas vegetais foram feitas com um medidor portátil de fotossíntese (IRGA). Os dados foram analisados por meio de uma regressão não linear, e, nos dois casos, existe uma correlação negativa entre fotossíntese e área foliar lesionada, ou seja, quanto maior a área foliar lesionada, menor a fotossíntese; e o ponto de inflexão negativo da curva, no qual um pequeno aumento na área foliar lesionada resultou em uma grande perda fotossintética, é tomado como referência de nível de dano, sendo que o nível de controle destas pragas, esta abaixo destes valores. A condutância estomática, a transpiração foliar, a concentração interna de CO2 e a temperatura foliar, em ambos os casos, não demonstram uma correlação definida com a intensidade de danos. A transpiração foliar em limão cravo atacado por O. praelonga é maior nos pontos onde também é maior a condutância estomática, e nas folhas de café com ataque de L. coffeella a transpiração foliar mantem-se constante durante toda a curva, semelhante à variável condutância estomática. As relações matemáticas de fotossíntese/concentração interna de CO2, e fotossíntese/condutância estomática são, em ambos os casos, decrescentes, o que demonstra respectivamente queda na eficiência instantânea de carboxilação da rubisco e redução da eficiência intrínseca do uso da água em função do aumento da área foliar lesionada. A análise conjunta dos dados demonstrou que O. praelonga afeta o fotossistema I (PS I) de folhas de limão cravo; enquanto L. coffeella afeta, em primeiro plano, o fotossistema II (PS II). No caso de O. praelonga em limão cravo, determina-se a faixa de 7 a 13% de área foliar lesionada (de 40 a 70 cochonilhas/folha) como sendo o valor de nível de dano, e para L. coffeella em cafeeiro este valor ficou na faixa de 25 a 36% de área foliar lesionada (tecido consumido pelo inseto). Os valores obtidos em laboratório, necessitam ajustes efetivos na determinação do nível de controle destas pragas no campo. A técnica de leitura de fotossíntese mostrou-se adequada a este propósito, e a análise dessa variável demonstrou ser a melhor opção para tal correlação. / The goal of this work was to evaluate the effect of insect pests of different feeding habits in their host plants through readings of plant physiological variables as photosynthesis, stomatal conductance, leaf transpiration, internal carbon dioxide concentration and leaf temperature. Thus, one estimated the injury level of a sucking insect, Orthezia praelonga Douglas, 1891, in 'Rangpur' lime (Citrus limonia L.), and Leucoptera coffeella (Guérin-Mènevile, 1842), a chewing insect, in 'Obatã' coffee seedlings. The trials were carried out under optimum temperature conditions, with saturating light and CO2 , with different injured leaf area percentages, obtained by the variation of the number of insects per leaf, in the case of O. praelonga in 'Rangpur' lime (0-35 mealybugs/leaf (0-6%), 40-70 mealybugs/leaf (7-13%), 80-220 mealybugs/leaf (14-40%), and >220 mealybugs/leaf (>40%)), or through plant tissue consumed (0-25%, 26-36% and > 37% intervals), in the case of L. coffeella in coffee seedlings. Plant physiological variables readings were performed through a portable photosynthesis meter(IRGA). The data were analyzed by means of nonlinear regression, and, in both cases, a negative correlation was observed between photosynthesis and the injured leaf area, that is, the larger the injured leaf area, the lesser the photosynthesis; the negative inflection point of the curve, upon which a slight increase in the injured leaf area resulted in great photosynt hesis loss is taken as a damage level reference, and the control level of these pests is below these values. The stomatal conductance, leaf transpiration, internal CO2 concentration and the leaf temperature, in both cases, showed no defined correlation with the damage intensity. The leaf transpiration in 'Rangpur' lime attacked by O. praelonga is higher in points where the stomatal conductance is higher as well, and in coffee leaves attacked by L. coffeella the leaf transpiration remains constant throughout the curve, similarly to the stomatal conductance variable. The mathematical relationships of photosynthesis/internal CO2 concentration, and photosynthesis/stomatal conductance are, in both cases, decreasing, which respectively shows drop in instant Rubisco carboxylation efficiency and reduction of the intrinsic efficiency of water use according to the increase of the injured leaf area. The joint data analysis showed that O. praelonga affects photosystem I (PS I) of 'Rangpur' lime, while L. coffeella affects, at first, photosystem II (PS II). In the case of O. praelonga in 'Rangpur' lime the 7-13% range of the injured leaf area (40-70 mealybugs/leaf) is determined as the damage level value, and for L. coffeella in coffee the value ranges 25-36% of the injured leaf area (tissue consumed by the insect). The values found in laboratory require field validation for effective adjustments to determine the level to control these insect pests. Overall, the photosynthesis reading technique was shown adequate to this purpose, and the analysis of this variable was the best choice for such correlation.

Il est prévu une augmentation de l’intensité et de la fréquence des sécheresses dans les années à venir à cause des changements climatiques. Puisque la productivité des peupliers est étroitement liée à la disponibilité en eau, il existe un risque de déclin de la production de bois dans les peupleraies. L’optimisation de la biomasse produite en regard de l’eau consommée (efficience d’utilisation de l’eau, WUE) apparaît alors être une question de recherche prometteuse. Des études précédentes ont montré une diversité clonale de WUE chez les peupliers, pilotée principalement par la conductance stomatique (gs). Cependant, gs et l’assimilation en CO2 ne sont pas toujours connectés, ce qui peut conduire à de fortes variations de WUE au niveau foliaire. De plus, puisque la mesure de l’efficience d’utilisation de l’eau au niveau de la plante entière (TE) est laborieuse à mesurer, les expérimentations sont souvent réalisées en serre. Toutefois, les conditions contrôlées d’une serre conduisent à un environnement très différent des conditions naturelles, et les comparaisons de WUE entre conditions contrôlées et naturelles sont rares dans la littérature. Nous avons évalué la diversité des dynamiques stomatiques au sein de génotypes de peupliers sous conditions témoins et sous sécheresse en serre et en pépinière. Nous avons examiné le lien entre différents facteurs physiologiques, morphologiques et moléculaires et les dynamiques stomatiques, ainsi que leur influence sur TE. De plus, nous avons étudié la relation entre différents estimateurs de WUE et ses composantes entre des conditions contrôlées et naturelles. Le contenu en éléments minéraux et l’expression de gènes candidats ont également été quantifiés à deux moments de la journée pour analyser leur relation avec gs. Nous avons observé une variabilité génotypique significative des dynamiques stomatiques à la fois en réponse à l’irradiance et au VPD, de plus modifiée par la sécheresse et les conditions de croissance. La taille et la densité des stomates ainsi que la transpiration foliaire étaient fortement corrélées aux dynamiques stomatiques en serre, mais très peu en pépinière. Ces résultats soulignent l’importance et la complexité de ces mécanismes à l’échelle de la plante entière. WUE au niveau de la feuille et de la plante entière étaient relativement stables au sein des génotypes et entre conditions de croissance, mais bien moins avec la sécheresse. Enfin, des contenus en éléments et des expressions géniques distinctes ont été observées entre faces de la feuille et enter moments de la journée, en lien avec gs. Ces résultats fournissent de précieuses informations pour mieux comprendre les divers mécanismes foliaires pilotant WUE au niveau de la plante entière. / The number of drought events is expected to increase in intensity and frequency as a result of climate change. Since poplar productivity is closely linked to water availability, there is an increasing risk of decline in wood production from poplar plantations. Optimization of the ratio of biomass production to water used (i.e. water use efficiency, WUE) appears therefore as a relevant target for poplar research. Previous studies have shown the clonal diversity of WUE in poplar is driven mainly by stomatal conductance (gs). However gs and photosynthesis are not always tightly coupled which can result in large variations of WUE at leaf level. Additionally, because transpiration efficiency (TE) is laborious to measure, experiments are often conducted in pots in glasshouses. However in controlled conditions the environment is widely different than in the field and comparisons of WUE in controlled and field conditions are scarce in the literature. We assessed the diversity of stomatal dynamics among poplar genotypes under control or drought conditions grown in a glasshouse and in the field. We investigated the link between physiological, morphological and molecular factors and stomatal dynamics, and their influence on TE. Furthermore, we examined the relation between different estimators of WUE and its components between controlled and field conditions. Element content and candidate gene expression in the guard cells were also quantified at two times during the day to analyze their link to stomatal conductance. We found among the four genotypes studied significant genotypic variability of stomatal dynamics to irradiance and VPD which was altered by drought and growing conditions. Stomatal size and density as well as water use, but not WUE, were correlated to stomatal dynamics, emphasizing the importance and complexity of such mechanisms at the whole plant scale. Good agreements between leaf-level and whole-plant WUE among genotypes and between growing conditions were also found. Finally, distinct guard cell element contents and candidate gene expression, between leaf sides and time of day, linked with stomatal conductance draw attention to the diversity of components contributing to TE. These findings provides valuable information to better understand the diverse, sometimes unsuspected, leaf-level mechanisms driving water use efficiency at the whole plant scale.

Water availability is a strategy resource for forest plantation. Many authorities and researches are concerned about the water use and the impact of forest plantation. Water use and water use efficiency have been measuring in all over the world. High productivity of Eucalyptus sp plantation are depend of environmental resources such water, nutrients, light and also genotype resource efficiency. High water use is also associated with high productivity and water use efficiency. Many reports were published about water use in eucalyptus plantation. Water use might vary among 1100 mm to 1300 mm for eucalyptus plantation. Climate conditions, soil characteristics and forest management might influence water use. Currently, studies aim to understand hydrology cycle at the leaf, trees and on landscape scale. Previous studies showed that K fertilizer increase water demand. Leaf biomass and LAI also increase due to K fertilizer application, which suggest increase in water use. Eucalyptus forest plantation may also decrease water discharge in catchment, which might decrease water availability in local scale. However, transpiration varied within soil moisture, precipitation, temperature, atmosphere conditions, fertilizer application, genotype and latitude. The main objective of forest managers was often find a technique regime which forester may use to achieve the target growth rate. Nowadays, it is important to manage the forest taking to account local resource supply, local climate condition and resource availability. These strategies might increase the sustainability of forest plantation. Measurement of physiological functioning might help forests manager to understand the growth response of our forest as result of climate condition and also planning new strategies to increase forest sustainability. / A alta produtividade das florestas de Eucalyptus sp está diretamente associada aos recursos disponíveis no ambiente como água, nutrientes e luz, como também pelo uso eficiente dos recursos por diferentes genótipos. Diversos trabalhos foram realizados sobre o uso da água das florestas de eucalipto. Pesquisadores e gestores florestais sempre são questionados sobre o uso da água e a eficiência do uso da água pelas florestas de eucalipto. Diversos trabalhos mostraram que o uso da água em florestas de eucalipto podem alcançar 1100 mm a 1300 mm. No entanto, essas estimativas podem variar em função das condições edafoclimáticas e de manejo da floresta O objetivo principal dos estudos atuais é entender a dinâmica do ciclo da água em diferentes escalas da floresta, na folha, a árvore e na escala da bacia hidrográfica. Alguns estudos vêm mostrando que a adubação, em particular com potássio, também pode aumentar a demanda de água por parte das árvores. O K propicia aumento de biomassa foliar e IAF das plantas, sugerindo aumento da transpiração das árvores. Estudos na escala da bacia hidrográfica, mostraram que bacias hidrográficas ocupadas por florestas de eucalipto podem reduzir o fluxo superficial dos cursos da água como também o estoque de água nas diferentes camadas do solo, o que pode comprometer a disponibilidade hídrica numa escala local. Por outro lado, alguns trabalhos mostraram que os impactos das florestas plantadas nos recursos hídricos dependem do regime pluviométrico local. Outros fatores podem influenciar o uso da água pelas florestas tais como a capacidade de retenção de água no solo, condições atmosféricas, espaçamento e genótipos. O principal objetivo dos gestores florestais, frequentemente, tem sido a busca por uma técnica de manejo florestal que permita o alcance de altas taxas de produtividade dos genótipos plantados. Atualmente, o manejo florestal não leva em conta a disponibilidade dos recursos ambientais, principalmente a água por meio do regime pluviométrico. Essas estratégias são importantes para aumentar a sustentabilidade das florestas plantadas, principalmente em áreas em que a disponibilidade de água é crítica. A compreensão da dinâmica dos parâmetros fisiológicos pode ajudar os gestores florestais a entenderem as respostas das árvores em função das condições climáticas e planejar estratégias que possam aumentar a sustentabilidade dos plantios florestais de Eucalyptus sp.

The forest product industry is keenly interested in extending the normal planting season, as well as in the comparative field performance of standard nursery bare-root seedlings and containerized rooted cuttings. The effect of seasonal planting dates on survival, above and belowground biomass allocation, water relations, gas exchange attributes and foliar carbon isotope composition (δ13C) of two stock types of slash pine (Pinus elliottii Engelm.) were examined. Slash pine bare-root seedlings (BRS) and containerized rooted cuttings (CRC) were hand planted in September, November, January, March and April in three consecutive planting seasons (2000-2001, 2001-2002 and 2002-2003) on three sites with silt loam topsoils in southwestern Louisiana. First-year mean survival of CRC across all planting dates and sites was consistently high at 96 to 98%, whereas BRS survival was significantly (P < 0.0001) lower at 59 to 81% and highly variable among study sites and dates through three planting seasons. Generally, there was a negative relationship between soil moisture at the time of planting and first-year survival of BRS planted September through March in 2001-2002 and 2002-2003 planting seasons, whereas the opposite was observed only for BRS planted in April 2002 and 2003. Survival of CRC was affected very little by the variation in soil moisture. Containerized rooted cuttings had higher early above and belowground biomass, and height and diameter than did BRS. However, three years after planting the size differences between stock types disappeared or became negligible. Early size differences among trees planted September through March also decreased after three years, although September trees were tallest. Growth of the April-planted trees was poor compared to trees planted in other months. Late-planted April trees had higher δ13C values, and higher water-use efficiency in the first growing season compared to earlier planted trees. Differences in δ13C values among the planting dates disappeared in the second growing season. Net photosynthesis rates did not differ considerably between stock types or among planting dates in the second and third growing seasons. This study indicates that it is possible to extend the planting season to as early as September and as late as March by using CRC.

The forest product industry is keenly interested in extending the normal planting season, as well as in the comparative field performance of standard nursery bare-root seedlings and containerized rooted cuttings. The effect of seasonal planting dates on survival, above and belowground biomass allocation, water relations, gas exchange attributes and foliar carbon isotope composition (&#948;13C) of two stock types of slash pine (Pinus elliottii Engelm.) were examined. Slash pine bare-root seedlings (BRS) and containerized rooted cuttings (CRC) were hand planted in September, November, January, March and April in three consecutive planting seasons (2000-2001, 2001-2002 and 2002-2003) on three sites with silt loam topsoils in southwestern Louisiana. First-year mean survival of CRC across all planting dates and sites was consistently high at 96 to 98%, whereas BRS survival was significantly (P < 0.0001) lower at 59 to 81% and highly variable among study sites and dates through three planting seasons. Generally, there was a negative relationship between soil moisture at the time of planting and first-year survival of BRS planted September through March in 2001-2002 and 2002-2003 planting seasons, whereas the opposite was observed only for BRS planted in April 2002 and 2003. Survival of CRC was affected very little by the variation in soil moisture. Containerized rooted cuttings had higher early above and belowground biomass, and height and diameter than did BRS. However, three years after planting the size differences between stock types disappeared or became negligible. Early size differences among trees planted September through March also decreased after three years, although September trees were tallest. Growth of the April-planted trees was poor compared to trees planted in other months. Late-planted April trees had higher &#948;13C values, and higher water-use efficiency in the first growing season compared to earlier planted trees. Differences in &#948;13C values among the planting dates disappeared in the second growing season. Net photosynthesis rates did not differ considerably between stock types or among planting dates in the second and third growing seasons. This study indicates that it is possible to extend the planting season to as early as September and as late as March by using CRC.

Made available in DSpace on 2016-08-12T19:15:30Z (GMT). No. of bitstreams: 1 MaykyFPL_Dissert.pdf: 583480 bytes, checksum: b5156cac19b83224804fef6b4df642d2 (MD5) Previous issue date: 2015-02-23 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / There is no doubt that the effect of weed causes damage to various human activities and especially those for agricultural use. Therefore, if not properly handled, can reduce productivity and production quality due to competition for light, nutrients, and especially water, which is the most abundant resource, while the most limiting to agricultural productivity. This study aimed to assess the potential for competition four weed species by water. The experiment was conducted in a factorial 4 x 2, distributed in a randomized complete block design, with five replications. were studied species malva-branca (Waltheria indica L.); crotalária (Crotalaria retusa L.); mussambê (Cleome affinis DC.) and trapoeraba (Commelina benghalensis L.), with two water regimes (with and without water stress). Plants subjected to water stress had suspended irrigation during flowering, and maintained until the CO2 assimilation rate of plants to morning 9am reached values close to zero, at the resumed irrigation. As from the date irrigation suspension the plants were submitted to the following evaluations: water potential before dawn (&#936;AM) and water potential at noon (&#936;MD) (MPa); photosynthesis (A; CO2 &#956;mol m-2); stomatal conductance (gs; &#956;mol H2O m-2 s-1), and transpiration (E; mmol H2O m-2 s-1) carried out every day until the photosynthetic rates of plants subjected to water stress is to equalize plants without stress. At the end of the experiment was measured leaf area (cm2), the dry mass of roots, stems, leaves and total (g), the chlorophyll content index near the apex of the leaves and the next leaves the base. Was also determined daily water consumption species (mL). The results grouped the plants into two groups: trapoeraba and mussambê, considered conservative, keeping the high water potential and transpiration, being uncompetitive by water, and crotalária and malva-branca, medium investors, able to reduce the water potential and stomatal aperture values higher, resulting in greater potential for competition for water. And in low water availability conditions, the mauve-white is the most competitive for water, because it can maintain high water consumption levels over time / Não há dúvidas de que a interferência das plantas daninhas causa prejuízos a diversas atividades do ser humano e principalmente aquelas destinadas à agricultura. Por isso, se não forem manejadas adequadamente, podem reduzir a produtividade e a qualidade da produção, devido à competição por luz, nutrientes e principalmente água, que é o recurso mais abundante e, ao mesmo tempo, o mais limitante à produtividade agrícola. O presente trabalho teve como objetivo avaliar o potencial de competição de quatro espécies de plantas daninhas por água. O experimento foi conduzido no esquema fatorial 4 x 2, distribuídos no delineamento experimental em blocos casualizados, com cinco repetições. Foram estudadas as espécies malva-branca (Waltheria indica L.); crotalária (Crotalaria retusa L.); mussambê (Cleome affinis DC.) e trapoeraba (Commelina benghalensis L.)], com dois regimes hídricos (com e sem estresse hídrico). As plantas submetidas ao estresse hídrico tiveram a irrigação suspensa por ocasião do florescimento, e mantida até a taxa de assimilação de CO2 das plantas às 9h da manhã atingisse valores próximos a zero, quando foi retomada a irrigação. A partir da data da suspensão da irrigação as plantas foram submetidas às seguintes avaliações: potencial hídrico antes do amanhecer (&#936;AM) e potencial hídrico ao meio dia (&#936;MD) (MPa); fotossíntese (A; &#956;mol CO2 m-2); condutância estomática (gs; &#956;mol H2O m-2 s-1), e a transpiração (E; mmol H2O m-2 s-1) realizadas todos os dias até que as taxas de fotossíntese das plantas submetidas ao estresse hídrico se igualassem à das plantas sem estresse. Ao final do experimento foi mensurada a área foliar (cm2), a massa seca das raízes, caules, folhas e total (g), o Índice de conteúdo de clorofila das folhas próximas ao ápice e das folhas próximas a base. Também foi determinado o consumo de água diário das espécies (mL). Os resultados permitiram agrupar as plantas em dois grupos: trapoeraba e mussambê, consideradas como conservadoras, mantendo o potencial hídrico alto e com baixa transpiração, sendo pouco competitivas por água, e crotalária e malva-branca, medianamente investidoras, capazes de reduzir o potencial hídrico e com valores de abertura estomática mais altos, implicando em maior potencial de competição por água. E em condições de baixa disponibilidade de água, a malva-branca é a mais competitiva por água, pois consegue manter altos valores de consumo de água por mais tempo

Made available in DSpace on 2016-08-12T19:18:48Z (GMT). No. of bitstreams: 1 MaykyFPL_Dissert.pdf: 583480 bytes, checksum: b5156cac19b83224804fef6b4df642d2 (MD5) Previous issue date: 2015-02-23 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / There is no doubt that the effect of weed causes damage to various human activities and especially those for agricultural use. Therefore, if not properly handled, can reduce productivity and production quality due to competition for light, nutrients, and especially water, which is the most abundant resource, while the most limiting to agricultural productivity. This study aimed to assess the potential for competition four weed species by water. The experiment was conducted in a factorial 4 x 2, distributed in a randomized complete block design, with five replications. were studied species malva-branca (Waltheria indica L.); crotalária (Crotalaria retusa L.); mussambê (Cleome affinis DC.) and trapoeraba (Commelina benghalensis L.), with two water regimes (with and without water stress). Plants subjected to water stress had suspended irrigation during flowering, and maintained until the CO2 assimilation rate of plants to morning 9am reached values close to zero, at the resumed irrigation. As from the date irrigation suspension the plants were submitted to the following evaluations: water potential before dawn (&#936;AM) and water potential at noon (&#936;MD) (MPa); photosynthesis (A; CO2 &#956;mol m-2); stomatal conductance (gs; &#956;mol H2O m-2 s-1), and transpiration (E; mmol H2O m-2 s-1) carried out every day until the photosynthetic rates of plants subjected to water stress is to equalize plants without stress. At the end of the experiment was measured leaf area (cm2), the dry mass of roots, stems, leaves and total (g), the chlorophyll content index near the apex of the leaves and the next leaves the base. Was also determined daily water consumption species (mL). The results grouped the plants into two groups: trapoeraba and mussambê, considered conservative, keeping the high water potential and transpiration, being uncompetitive by water, and crotalária and malva-branca, medium investors, able to reduce the water potential and stomatal aperture values higher, resulting in greater potential for competition for water. And in low water availability conditions, the mauve-white is the most competitive for water, because it can maintain high water consumption levels over time / Não há dúvidas de que a interferência das plantas daninhas causa prejuízos a diversas atividades do ser humano e principalmente aquelas destinadas à agricultura. Por isso, se não forem manejadas adequadamente, podem reduzir a produtividade e a qualidade da produção, devido à competição por luz, nutrientes e principalmente água, que é o recurso mais abundante e, ao mesmo tempo, o mais limitante à produtividade agrícola. O presente trabalho teve como objetivo avaliar o potencial de competição de quatro espécies de plantas daninhas por água. O experimento foi conduzido no esquema fatorial 4 x 2, distribuídos no delineamento experimental em blocos casualizados, com cinco repetições. Foram estudadas as espécies malva-branca (Waltheria indica L.); crotalária (Crotalaria retusa L.); mussambê (Cleome affinis DC.) e trapoeraba (Commelina benghalensis L.)], com dois regimes hídricos (com e sem estresse hídrico). As plantas submetidas ao estresse hídrico tiveram a irrigação suspensa por ocasião do florescimento, e mantida até a taxa de assimilação de CO2 das plantas às 9h da manhã atingisse valores próximos a zero, quando foi retomada a irrigação. A partir da data da suspensão da irrigação as plantas foram submetidas às seguintes avaliações: potencial hídrico antes do amanhecer (&#936;AM) e potencial hídrico ao meio dia (&#936;MD) (MPa); fotossíntese (A; &#956;mol CO2 m-2); condutância estomática (gs; &#956;mol H2O m-2 s-1), e a transpiração (E; mmol H2O m-2 s-1) realizadas todos os dias até que as taxas de fotossíntese das plantas submetidas ao estresse hídrico se igualassem à das plantas sem estresse. Ao final do experimento foi mensurada a área foliar (cm2), a massa seca das raízes, caules, folhas e total (g), o Índice de conteúdo de clorofila das folhas próximas ao ápice e das folhas próximas a base. Também foi determinado o consumo de água diário das espécies (mL). Os resultados permitiram agrupar as plantas em dois grupos: trapoeraba e mussambê, consideradas como conservadoras, mantendo o potencial hídrico alto e com baixa transpiração, sendo pouco competitivas por água, e crotalária e malva-branca, medianamente investidoras, capazes de reduzir o potencial hídrico e com valores de abertura estomática mais altos, implicando em maior potencial de competição por água. E em condições de baixa disponibilidade de água, a malva-branca é a mais competitiva por água, pois consegue manter altos valores de consumo de água por mais tempo

Baby spinach is a relatively new crop in South Africa with both commercial significance and reputed health benefits. It is known to assist in combating degenerative conditions associated with ageing, such as heart disease, cardiovascular disease, Alzheimer’s disease, cataracts and several forms of cancer. Three parallel NPK trials were conducted to investigate the effects of nitrogen (N), phosphorus (P) and potassium (K) on the growth and development of baby spinach. N and P treatments were arranged as (0, 45, 75, 105, 120 kg.ha -1 N and P), and K treatments were arranged as (0, 63, 85, 127, 148 kg.ha -1) in a randomised complete block designed with four replicates. Results showed that yield, dry matter, chlorophyll content and Leaf Area Index (LAI) were significantly increased by increasing the N application, while K had a significant effect on the LAI but not on yield, dry matter, chlorophyll content or stomatal conductance. Nitrogen treatments quadrupled fresh yield, dry matter and chlorophyll content, reaching maximum impact at 75 kg.ha-1 N. Phosphorus application showed significantly increased yields, dry matter and chlorophyll content, reaching maximum impact at 75 kg.ha-1 P. Therefore, to achieve optimum growth with N and P, 75 kg.ha-1 is recommended. The optimum rates of N, P and K were then used to formulate a NPK combined trial which was arranged as 0, 30:30:40, 45:45:60, 60:60:70, 75:75:90 kg.ha-1 in a randomised complete block design with three replicates. The results showed that maximum impact on yield, chlorophyll content, fresh and dry matter was achieved when combined NPK was applied at 45:45:60 / Agriculture and  Animal Health / M. Sc. (Agriculture)