The Tropical savannas of central Brazil (cerrado) and the Everglades wetland (Florida) ecosystems are ideal systems to study landscape spatial mosaics and their interactions. Both ecosystems show a variety of plant physiognomies distributed within small spatial scales and elevation gradients. Such variety of plant physiognomies provide an opportunity to investigate the roles of climate, topography, nutrient availability and water table dynamics as determinants of plant physiognomic distributions, and their role in shaping regional systems. South Florida Wetlands and the tropical savannas of central Brazil are examples of hydrologically-controlled ecosystems. In hydrologically-controlled ecosystems water sources, the availability of nutrients, and the patterns of water movement play important roles in determining vegetation structure and function. The main objective of this study was to understand ecosystem level processes that shape different physiognomies in two hydrologically-controlled ecosystems. I conducted field work at the IBGE ecological reserve, a field experimental station located in Brasilia, Brazil. I also worked at the Everglades National Park in an area located near the south entrance of the Park in Homestead, Florida. I carried out three interconnected studies investigating water and nutrient dynamics: (1) In a Brazilian savanna I manipulated levels of litter input and measured changes to soil properties, organic matter decomposition and tree growth. I found that changes in litter input affect soil physicochemical properties and soil biochemical processes. I also found that litter dynamics influence tree growth through their effects on soil physicochemical properties. (2) I also studied the effect of water table depth and its temporal variation on spatial patterns of vegetation distribution in the cerrado landscape. I monitored diurnal and seasonal changes in water table depth along two tree-density and topographic gradients. In addition, I measured woody species composition, growth rates of four tree species, litter production, soil nutrients, and nutrient resorption efficiency along those two gradients. I found that water table depth has an important role in determining the spatial distribution of cerrado physiognomies; it also affects tree growth, species composition and nutrient resorption efficiency. (3) In the Everglades I studied patterns of underground water uptake by two vegetation types. I monitored seasonal and diurnal changes in water table depth in a Hammock forest, in a stand dominated by the invasive woody species Schinus terebinthifolius, as well as the water level in an adjacent lake. I estimated stand level transpiration using two different approaches: with sap flow measurements and diurnal oscillations in water table levels. Then, I calculated the total quantity of groundwater withdrawn by evapotranspiration for the wet and dry seasons in the Hammocks and in the exotic invaded site and then compared the results. I found that water uptake by Everglades trees is well coupled to diurnal changes in water table depth and that the amount of water withdrawn from the groundwater was larger during the wet season than during the dry season. Finally, I detected hydrological feedbacks between different vegetation types and nearby bodies of water. Results of this study contributes to the current knowledge of ecosystem level processes in tropical and subtropical ecosystems where water circulation and water availability play a dominant role in shaping vegetation structure and function.

Submitted by (lucia.rodrigues@ufrpe.br) on 2016-08-31T10:53:10Z No. of bitstreams: 1 Maria Alice Vasconcelos da Silva (1).pdf: 762537 bytes, checksum: c100c2c556639aa3d440082da1ef7bb5 (MD5) / Made available in DSpace on 2016-08-31T10:53:10Z (GMT). No. of bitstreams: 1 Maria Alice Vasconcelos da Silva (1).pdf: 762537 bytes, checksum: c100c2c556639aa3d440082da1ef7bb5 (MD5) Previous issue date: 2007-08-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This work aimed to study the effect of water deficit on gas exchange, leaf water potential, dry matter production, and some biochemical aspects of Schinus terebinthifolius Raddi. young plants. A research project was developed, under greenhouse conditions, at the Laboratório de Fisiologia Vegetal, Departamento of Biologia of Universidade Rural de Pernambuco between November, 2005 to February, 2006. Seedlings with 3 month-old and sexually propagated were cultivated in containers containing 5.5 kg of soil. The entirely randomized experimental design was used, with four water treatments (100%, 75%, 50% and 25% to field capacity-FC), with four replicates. Plants under 25% FC were re-watered to 100% FC once after stomatal closure. After 15 days of acclimation period have started the water treatments. The experimental period lasted for 74 days. Transpiration (E), diffusive resistance (Rs), leaf temperature (Tfol), air temperature (Tar), relative humidity of the air (UR), photosynthetically active radiation (PAR), and vapor pressure deficit (VPD) were evaluated at midday each seven days. At the end of the experimental period, leaf water potential (Yf) was measured at midday. Leaves (LDM), stems (SDM), roots (RDM), and total dry masses (TDM), root to shoot ratio (R/Sh), and leaves (LBA), stems (SBA) and roots biomass allocation (RBA) were determined. In addition, carbohydrates, free proline, soluble protein and free amino acids contents were analyzed. In plants under 25% field capacity, stomatal closure was observed after 11 days of water treatments. At the time plants were re-watered to 100% FC. After 24 h plants re-watered recovered the stomatal aperture, which remained open until the end of the experimental period. Water deficit decreased the leaf water potential (Yf) in plants grown at 25% FC (-2.2 MPa) when compared with the 100% FC treatment (-1.1 MPa). Plants grown under 75% FC producted higher LDM, SDM and RDM than the other treatments. Differences among treatments to biomass allocation were not observed, but there was a tendency to plants grown under 25% of FC to increase more biomass allocation than the other treatments. The water stress reduced carbohydrates contents and increased soluble protein and amino acids. However, differences to proline content were not verified among water treatments. These results suggest that this species is tolerate to low humidity levels in the soil and that the level of 75% of FC is the best to cultivate it in the initial fase of development. / Com o objetivo de estudar os efeitos do déficit hídrico sobre as trocas gasosas, o potencial hídrico foliar, a produção de matéria seca e alguns aspectos bioquímicos de plantas jovens de Schinus terebinthifolius Raddi, foi desenvolvido um trabalho em casa de vegetação do Laboratório de Fisiologia Vegetal do Departamento de Biologia da Universidade Federal Rural de Pernambuco, no período de novembro de 2005 a fevereiro de 2006. Utilizaram-se mudas com três meses de idade, propagadas sexuadamente, as quais foram transferidas para vasos de polietileno contendo 5,5 kg de solo. Adotou-se um delineamento experimental inteiramente casualizado, representado por quatro tratamentos hídricos (100% da Capacidade de pote; 75% CP; 50% CP; 25% CP) com quatro repetições. Após 15 dias sob aclimatação, procedeu-se o início dos tratamentos hídricos. Durante o período experimental foram efetuadas medições das trocas gasosas do vapor d’água às 12 horas em intervalos de 7 dias. Avaliou-se a transpiração (E), a resistência difusiva (Rs), a temperatura foliar (Tf), a temperatura do ar (Tar), a umidade relativa do ar (UR), a radiação fotossinteticamente ativa (RFA) e o déficit de pressão de vapor (DPV). No final do período experimental foi mensurado o potencial de água da folha (Yf) às 12 horas e determinado o peso da matéria seca das folhas (MSF), dos caules (MSC), das raízes (MSR), a matéria seca total (MST), a relação raiz/parte aérea (R/Pa) e a alocação de biomassa para as folhas (ABF), caules (ABC) e para as raízes (ABR). Além disso, foram analisados os teores de carboidratos, de prolina livre, proteínas solúveis e aminoácidos livres. O fechamento estomático ocorreu em plantas submetidas a 25% CP, aos 11 dias após a diferenciação dos tratamentos hídricos quando as plantas foram reirrigadas para 100% CP. Após 24 horas houve recuperação da abertura estomática mantendo-se até o final do experimento. O déficit hídrico reduziu o potencial hídrico foliar (Yf) nas plantas do tratamento estresse moderado (–2,2 MPa) quando comparado com o controle (-1,1 MPa). As plantas do tratamento 75% CP se destacaram em relação aos demais tratamentos, por produzirem mais matéria seca para as folhas (MSF), caule (MSC) e raízes (MSR). Com relação à alocação de biomassa, não houve diferença significativa entre os tratamentos, porém houve uma tendência do tratamento 25% CP alocar mais biomassa para do que os demais tratamentos. Em relação aos solutos orgânicos, o déficit hídrico provocou reduções nos teores de carboidratos e aumento no teor de proteínas e aminoácidos, não havendo diferença entre os tratamentos para os teores de prolina. Os resultados sugerem que a aroeira é tolerante a baixos níveis de umidade no solo e que o nível de 75%CP é o mais indicado para o cultivo desta espécie na fase de muda.

Lasioderma serricorne (F.) (Fabricius, 1792) (Coleoptera: Anobiidae) is a cosmopolitan plague popularly known as a tobacco beetle that attacks a wide variety of stored agricultural products, like soybeans, escavating galleries in the grains while feeding and consequently generating losses to the producers by the loss of quality and value of the seeds. Due to the risks of intoxication and environment contamination with chemical residues, as well as the emergence of resistant individuals, other approaches to the control of L. serricorne have been sought. The host plant kairomones are molecules with potential for application as food attractants in traps for monitoring and capture insects. On the other hand, the evaluation of essential oils (EO) of native plants cultivated locally, can contribute to the discovery of useful compounds as natural repellents or bio-insecticides, also generating tools useful in integrated pest management (IPM). The objective of this study was to investigate and identify the volatile organic compounds released by stored soybeans from 3 varieties cultivated in Brazil with attractiveness to adults L. serricorne (soybean marketed in large supermarket chains in Maceió-AL and two varieties EMBRAPA BRS284 and BRS360RR) and to test the EO activity of the mature fruits of Schinus terebinthifolius, in order to promote the prospection of natural compounds with potential for application in the integrated management of this pest in storage environments. The attractiveness of grains and extracts prepared by dynamic headspace collection was evaluated in 4-arm olfactometer behavioral bioassays, while the isolation and identification of the bioactive compounds were carried out using gas chromatography coupled to electroanthennography (GC-EAG) and gas chromatography coupled to mass spectrometry (GC-MS). Five EAG-active compounds were identified in the extracts of soybeans: 1-octen- 3-ol, 3-octanol, 1- nonanol, linalool and limonene. The behavioral response of L. serricorne in 4-arm olfactometer bioassays to synthetic compounds was statistically significant for 1- octen-3- ol, 3-octanol, 1-nonanol and linalool, while the attraction for the 4 synthetic blend was comparable to that verified for soybeans. The activity of the EO extracted by steam-drag of the mature fruits of S. terebinthifolius (3 replicates) harvested from matrices located on the A. C. Simões Campus of UFAL, Maceió-AL, on L. serricorne adults was tested in 4-arm olfactometer bioassays , in two concentrations (1 and 10 μL), while the EO composition was analyzed by GC-FID and GC-MS. EO repellency was checked at a dose of 10 μL. A total of 14 compounds were identified in S. terebinthifolius EO, with the main components being β-pinene (49.8%), α-pinene (33.49%), 3-carene (5.85%), germacrene-D (2.08%) and bornylene (1.21%). The attractive compounds identified from the soybean grains act as kayromones for L. serricorne, while the S. terebinthifolius EO has repellent activity against this pest, so the results obtained here can be applied in the development of bioproducts for the integrated management of L. serricorne in and around storage environments, favoring the rational use of insecticides. / Lasioderma serricorne (F.) (Fabricius, 1792) (Coleoptera: Anobiidae) é uma praga cosmopolita conhecida popularmente como besourinho do tabaco que ataca uma grande variedade de produtos agrícolas armazenados, dentre eles a soja, escavando galerias nos grãos enquanto se alimentam e consequentemente gerando prejuízos aos produtores pela perda da qualidade e valor das sementes. Devido aos riscos de intoxicação e de contaminação do meio ambiente com resíduos químicos, assim como o surgimento de indivíduos resistentes, outras abordagens para o controle de L. serricorne tem sido buscadas. Os cairomônios das plantas hospedeiras são moléculas com potencial para aplicação como atraentes alimentares em armadilhas para monitoramento e captura de insetos. Por outro lado, a avaliação de óleos essenciais (OE) de plantas nativas cultivadas localmente, pode contribuir para a descoberta de compostos úteis como repelentes ou bioinseticidas naturais, gerando também ferramentas úteis manejo integrado de pragas (MIP). O objetivo desse estudo foi investigar e identificar os compostos orgânicos voláteis liberados pelos grãos de soja armazenados de três variedades cultivadas no Brasil com atratividade para adultos de L. serricorne (soja comercializada em grandes cadeias de supermercados em Maceió-AL e duas variedades EMBRAPA BRS284 e BRS360RR) e testar a atividade do OE dos frutos maduros de Schinus terebinthifolius, a fim de promover a prospecção de compostos naturais com potencial para aplicação no manejo integrado dessa praga em ambientes de armazenamento. A atratividade dos grãos e de extratos preparados por coleta dinâmica do headspace dos grãos foi avaliada em bioensaios comportamentais em olfatômetro de 4 braços, enquanto o isolamento e identificação dos compostos bioativos foram realizados pelas técnicas de cromatografia gasosa acoplada à eletroantenografia (CG-EAG) e cromatografia gasosa acoplada à espectrometria de massas (CG-EM). Cinco compostos EAG-ativos foram identificados nos extratos dos grãos de soja: 1-octen- 3-ol, 3-octanol, 1-nonanol, linalol e limoneno. A resposta comportamental de L. serricorne em bioensaios em olfatômetro de 4 braços aos compostos sintéticos foi estatisticamente significativa para 1-octen- 3-ol, 3-octanol, 1- nonanol e linalol, enquanto a atração pela mistura dos 4 compostos sintéticos foi comparável à verificada para os grãos de soja. A atividade do OE extraído por arraste a vapor dos frutos maduros de S. terebinthifolius (3 repetições) colhidos de matrizes localizadas no campus A. C. Simões da UFAL, Maceió-AL, sobre adultos de L. serricorne foi testada em bioensaios em olfatômetro de 4 braços, em duas concentrações (1 e 10μL), enquanto a composição do OE foi analisada por CG-FID e CG-EM. Foi verificada repelência do OE na dose de 10 μL. Foram identificados 14 compostos no OE de S. terebinthifolius, sendo os componentes principais: β-pineno (49,8 %), α-pineno (33,49 %), 3-careno (5,85 %), germancreno-D (2,08 %) e bornileno (1,21 %). Os compostos atrativos identificados a partir dos grãos de soja atuam como cairomônios para L. serricorne, enquanto o OE de S. terebinthifolius possui atividade repelente contra essa praga, portanto os resultados aqui obtidos podem ser aplicados no desenvolvimento de bioprodutos para o manejo integrado de L. serricorne dentro e ao redor de ambientes de armazenamento, favorecendo a utilização racional de inseticidas.