CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / A atividade florestal tem crescido nos Ãltimos anos movimentada pela crescente participaÃÃo nas exportaÃÃes nacionais. A demanda de novas Ãreas cresce a cada ano, e em algumas microrregiÃes o mercado de madeira apresenta importÃncia local como à o caso do Polo moveleiro de Marco localizado no estado do CearÃ. PorÃm essa regiÃo apresenta como principal empecilho para o plantio de espÃcies arbÃreas as caracterÃsticas de baixa disponibilidade hÃdrica que desponta como um dos principais assuntos discutidos em relaÃÃo aos impactos das mudanÃas climÃticas, principalmente em regiÃes Ãridas e semiÃridas. Com o objetivo de avaliar o efeito do estresse hÃdrico no desenvolvimento de plantas arbÃreas, foi conduzido um experimento com seis espÃcies florestais: Astronium fraxinifolium (GonÃalo Alves), Calophyllum brasiliense Cambess. (Guanandi), Tabebuia serratifolia (Vahl.) Nich. (IpÃâamarelo), Tabebuia impetiginosa (IpÃ-rosa), Simarouba amara Aubl. (MarupÃ) e Swietenia macrophylla King. (Mogno) em condiÃÃes irrigadas e de sequeiro. O experimento foi conduzido no municÃpio de AcaraÃ, CearÃ, Brasil (03Â27â06ââS; 40Â08â48ââW, 20m). Foram avaliadas variÃveis de umidade do solo, trocas gasosas, eficiÃncia no uso da Ãgua, temperatura da folha, eficiÃncia fotossintÃtica no uso de nitrogÃnio e fÃsforo, Ãndice SPAD, fluorescÃncia da clorofila, Ãrea foliar especÃfica, grau de suculÃncia foliar, altura da planta, diÃmetro do caule e taxas de crescimento absoluto e relativo. O dÃficit hÃdrico ocasionado pela sazonalidade das chuvas induz reduÃÃes na taxa de fotossÃntese, condutÃncia estomÃtica e transpiraÃÃo. As plantas em condiÃÃo de restriÃÃo hÃdrica aumentam a eficiÃncia intrÃnseca e momentÃnea do uso de Ãgua no perÃodo mais seco. Nas Ãpocas secas as plantas irrigadas controlam melhor a temperatura da folha mantendo-as mais baixas do que a do ar. A relaÃÃo interna/externa de CO2 foi afetada negativamente no mogno, guanandi e ipÃ-amarelo na Ãpoca mais seca. A eficiÃncia fotossintÃtica do uso do nitrogÃnio e fÃsforo à reduzida pelo dÃficit hÃdrico. A baixa disponibilidade de Ãgua no solo reduz a eficiÃncia quÃntica do fotossistema II no mogno e no guanandi. O Ãndice SPAD à reduzido na Ãpoca mais seca no mogno, guanandi e ipÃ-amarelo. As espÃcies ipÃ-amarelo, ipÃ-rosa e marupà irrigadas atà 1 ano, mantiveram um padrÃo de altura e diÃmetro do caule superior Ãs plantas irrigadas permanentemente no perÃodo de 24 meses. O estresse hÃdrico ocasiona quedas nas taxas de crescimento absoluto e relativo em altura e diÃmetro nas seis espÃcies estudadas. O marupà e o ipÃ-amarelo sÃo menos sensÃveis ao efeito do dÃficit hÃdrico, enquanto que o mogno, guanandi e gonÃalo alves sÃo mais afetadas. / The forestry activities have grown in recent years by busy growing participation in national exports. The demand for new areas grows every year, and some microregions wood is local importance such as the furniture Marco Polo located in the state of CearÃ, but the region is the main hindrance to the planting of tree species characteristics of low water availability that emerges as one of the main issues discussed in relation to the impacts of climate change, especially in arid and semiarid regions where the temperature increase being associated with events of strong reduction of the rainfall and increased evaporation. In order to evaluate the effect of water stress on the development of woody plants, an experiment was conducted with six forest species Astronium fraxinifolium, Calophyllum brasiliense Cambess., Tabebuia. serratifolia ( Vahl. ) Nich., Tabebuia impetiginosa, Simarouba amara Aubl. and Swietenia macrophylla King. in irrigated and rainfed conditions. The experiment was conducted in the municipality of AcaraÃ, CearÃ, Brazil (03  27 ' 06'' S 40  08 ' 48'' W. 20m). Variable soil moisture, gas exchange, water use efficiency, leaf temperature, photosynthetic efficiency in the use of nitrogen and phosphorus, SPAD index, chlorophyll fluorescence, specific leaf area, leaf degree of juiciness, and plant height were evaluated stem diameter and exchange absolute and relative growth. Water deficit caused by seasonal rains induces reductions in the rate of photosynthesis, stomatal conductance and transpiration. Plants on condition of water restriction and momentary increase the intrinsic efficiency of water use in the dry season. In the dry season plants irrigated better control the temperature of the sheet holding lower than that of air. The internal/external ratio of CO2 was negatively affected in mogno, guanandi and ipÃ-amarelo in the driest season. The photosynthetic efficiency of use of nitrogen and phosphorus is reduced by water deficit. The low availability of water in the soil reduces the quantum efficiency of photosystem II in mogno and guanandi. The SPAD index is reduced to the driest period in mogno, guanandi and ipÃ-amarelo. The species ipÃ-amarelo, ipÃ-rosa and marupà irrigated to 1 year, maintained a standard height and diameter of the upper stem to plants irrigated permanently within 24 months. Water stress causes declines in absolute and relative rates of growth in height and diameter in all six species. Growth rates follow the seasonal variation of precipitation in non-irrigated plants.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / A cana-de-aÃÃcar possui importÃncia mundial por armazenar grande quantidade de sacarose no colmo. Entretanto, sua produtividade à limitada por regulaÃÃo negativa na taxa fotossintÃtica modulada pela acumulaÃÃo de aÃÃcares no colmo (diminuiÃÃo na forÃa de dreno) ou pela acumulaÃÃo nas folhas (âfeedbackâ negativo). Outro fator responsÃvel pela reduÃÃo na fotossÃntese e acumulaÃÃo de sacarose no colmo à a presenÃa de deficiÃncia hÃdrica. Os mecanismos envolvidos com a reduÃÃo na produÃÃo de sacarose por acumulaÃÃo de aÃÃcares e seca ainda nÃo foram completamente esclarecidos. O objetivo deste trabalho foi avaliar os processos de inibiÃÃo da fotossÃntese e alteraÃÃes no metabolismo de aÃÃcares induzidos por aÃÃcares e deficiÃncia hÃdrica em plantas de cana-de-aÃÃcar. Para tanto, foram realizados dois estudos com plantas de cana-de-aÃÃcar com quatro meses de idade. No primeiro, foi aplicada soluÃÃo exÃgena de sacarose (50 mM) nas folhas expandidas de plantas mantidas em condiÃÃes de casa de vegetaÃÃo, seguidos de experimentos de dose e tempodependente de sacarose em segmentos foliares e finalizado por um experimento com aplicaÃÃo de aÃÃcares exÃgenos (sacarose, glicose e frutose 50 mM) nas folhas expandidas de plantas mantidas em condiÃÃes ambientais controladas em cÃmara de crescimento (fitotron). No segundo estudo, as plantas foram submetidas à suspensÃo de rega por cinco dias em duas condiÃÃes ambientais: casa de vegetaÃÃo com condiÃÃes naturais de temperatura elevada, alto dÃficit de pressÃo de vapor e alta densidade de fluxo de fÃtons fotossintÃticos (estresse severo) e o segundo em condiÃÃes controladas no fitotron (estresse moderado). A aplicaÃÃo de sacarose exÃgena causou mudanÃas no metabolismo de aÃÃcares [alteraÃÃo nos nÃveis de aÃÃcares e atividade de invertase Ãcida solÃvel (SAI) e neutra (NI), sintase de sacarose (SuSy) e sintase de sacarose fosfato (SPS)]. A sacarose causou forte reduÃÃo na assimilaÃÃo de CO2 e em parÃmetros da atividade do fotossistema II. Quando comparada com glicose e frutose, a sacarose causou maior reduÃÃo na fotossÃntese mÃxima, velocidade mÃxima de carboxilaÃÃo da PEPcase (Vpmax) e taxa mÃxima de regeneraÃÃo de PEP (Vpr). AlÃm disso, a sacarose causou forte inibiÃÃo na atividade de Rubisco, diminuiÃÃo no seu estado de ativaÃÃo e reduÃÃo em sua concentraÃÃo (expressÃo), enquanto que a atividade in vitro de PEPcase nÃo foi alterada. A deficiÃncia hÃdrica causou reduÃÃo das taxas fotossintÃticas com decrÃscimos dos parÃmetros de trocas gasosas e de fotoquÃmica, sugerindo limitaÃÃes estomÃticas e nÃo estomÃticas da fotossÃntese. As trocas gasosas foram mais afetadas nas condiÃÃes de casa de vegetaÃÃo em comparaÃÃo com o ambiente controlado. O tratamento de seca causou aumentos nos nÃveis de aÃÃcares solÃveis nas folhas apenas em condiÃÃes ambientais naturais e sob condiÃÃes controladas este tratamento gerou aumentos das atividades de NI e SPS enquanto que as atividades de SuSy e SPS em folhas nÃo foram alteradas. A fotossÃntese mÃxima foi diminuÃda acompanhando os decrÃscimos de Vpmax e Vpr, que foram associadas com diminuiÃÃo nas atividades e expressÃes de PEPcase e Rubisco. Diante dos resultados, concluise que sacarose modula negativamente a fotossÃntese em cana-de-aÃÃcar por exercer uma regulaÃÃo na expressÃo e atividade de Rubisco. Esse efeito induz uma reduÃÃo na taxa de carboxilaÃÃo in vivo de PEPcase provavelmente por um mecanismo indireto via modulaÃÃo da enzima. Por outro lado, a seca modula negativamente a fotossÃntese por mecanismos distintos, afetando as expressÃes e atividades de PEPcase e Rubisco que refletem em reduÃÃo nas taxas de carboxilaÃÃo do PEP. Nas duas situaÃÃes estudadas nÃo foi possÃvel elucidar o papel das mudanÃas no metabolismo de aÃÃcares na regulaÃÃo da fotossÃntese. Portanto, o presente estudo nÃo conseguiu elucidar como sacarose e/ou hexoses modificam a expressÃo e atividade de Rubisco e a seca altera as expressÃes e atividades de PEPcase e Rubisco. / The sugarcane has worldwide importance for storing large amounts of sucrose in the stalk. However, its production is limited by negative regulation in photosynthetic rate modulated by the sugars accumulation in the stalk (decrease in sink strength) or by the accumulation in the leaves (negative feedback). Another factor responsible for the reduction in photosynthesis and sucrose accumulation in the culm is the water deficiency presence. The mechanisms involved in the reduction in sucrose production by accumulation of sugars and drought are not yet completely understood. The aim of this study was to evaluate the inhibition processes of photosynthesis and changes in the metabolism of sugars induced by sugars and water stress in sugarcane plants. Therefore, two studies were conducted with sugarcane plants with four months old. At first, it was applied exogenous sucrose solution (50 mM) in the expanded leaves of plants grown in greenhouse conditions, followed by experiments on dose and timedependent sucrose in leaf segments and finalized by experiment with application of exogenous sugars (50 mM sucrose, glucose and fructose) in the expanded leaves of plants grown in controlled environmental conditions (phytotron). In the second study, the plants were subjected to irrigation suspension for five days in two environmental conditions: a greenhouse with natural conditions of high temperature, high vapor pressure deficit and high photosynthetic photon flux density (severe stress) and the second in phytotron conditions (moderate stress). The exogenous sucrose application caused changes in the sugars metabolism [alteration in sugars levels and activities of invertase acid soluble (SAI) and neutral (NI), sucrose synthase (SuSy) and sucrose phosphate synthase (SPS)]. Sucrose caused a strong reduction in CO2 assimilation and parameters of the activity of photosystem II. When compared with glucose and fructose, the sucrose caused greater reduction in maximum photosynthesis, carboxylation efficiency of PEP (Vpmax) and maximum rate of regeneration of PEP (Vpr). Furthermore, sucrose caused strong inhibition of Rubisco activity, decrease in its state of activation and reduction in its concentration (expression), whereas the PEPcase activity in vitro was unchanged. Water deficit caused decreases in photosynthetic rates, leaf gas exchange and photochemical, suggesting stomatal and non-stomatal limitations of photosynthesis. Gas exchanges were more affected in greenhouse conditions compared to the controlled environment of phytotron. Drought treatment caused increases in the soluble sugars levels in the leaves only in natural environmental conditions and under controlled conditions this treatment led to increases in NI and SPS activities while the activities of SuSy and SPS sheets were not changed. The maximum photosynthesis was decreased following the decrease of Vpmax and Vpr that were associated with a decrease in the PEPcase and Rubisco activities and expressions. Considering the results, it is concluded that sucrose negatively modulates photosynthesis of sugarcane per exercise a regulation in the Rubisco expression and activity. This effect leads to a reduction in the rate of carboxylation in vivo PEPcase probably by an indirect mechanism via modulation of the enzyme. Moreover, drought negatively modulates photosynthesis by different mechanisms affecting the Rubisco and PEPcase expression and activities reflecting reduction in the rates of carboxylation of PEP. In both cases studied was not possible to elucidate the role of changes in the metabolism of sugars in the regulation of photosynthesis. Therefore, the present study did not elucidate as sucrose and/or hexoses modify the Rubisco expression and activity and drought alters the Rubisco and PEPcase expression and activity.

CoordenaÃÃo de AperfeiÃoamento de NÃvel Superior / Objetivou-se com esta pesquisa avaliar diferentes tÃcnicas de superaÃÃo de dormÃncia, o comportamento germinativo sob condiÃÃes salinas e de dÃficit hÃdrico, o desenvolvimento de plÃntulas submetidas a diferentes potenciais de solutos com NaCl e relacionar as condiÃÃes estressantes com a mobilizaÃÃo de reservas cotiledonares em plÃntulas de copaÃba (Copaifera langsdorffii Desf.). Os tratamentos de superaÃÃo de dormÃncia constituÃram-se de imersÃes em Ãgua/24, 48 e 72 h; Ãgua quente, 50, 75 ÂC e fervente/10, 15 e 20 min, em H2SO4 (98,08)/15, 30 e 60 min e controle. Para as condiÃÃes estressantes, as sementes foram imersas em 100 mL de soluÃÃo de NaCl ou de PEG 6.000 com potenciais de solutos: [0,0 -0,2, -0,4, -0,6, -0,8 e -1,0 MPa]. Avaliaram-se a embebiÃÃo (durante 168 h), percentagem de germinaÃÃo (%G) Ãndice de velocidade de germinaÃÃo (IVG) e tempo mÃdio de germinaÃÃo (TMG). Para a mobilizaÃÃo das reservas, os tratamentos foram os mesmos potencias de solutos com NaCl. A semeadura foi em papel germitest e a germinaÃÃo em cÃmara do tipo BOD a 25 ÂC com fotoperÃodo de 12 horas, com cinco repetiÃÃes de 25 sementes por tratamento. Os estudos dos efeitos do NaCl nas plÃntulas de copaÃba fez-se em trÃs estÃdios de desenvolvimento: ED 1 (raiz com 5Â2 cm); ED 2 (emissÃo dos protÃfilos) e ED 3 (protÃfilos expandidos), Quinze plÃntulas por repetiÃÃo foram separadas em cotilÃdones e eixos embrionÃrios. Quantificaram-se a massa seca dos cotilÃdones e dos eixos embrionÃrios, os teores de lipÃdios, proteÃnas, amido, aÃÃcares solÃveis, aminoÃcidos e Ãons Na+, K+ e Cl-. Avaliaram-se as atividades das enzimas: lipase, liase do isocitrato, sintase do malato, α e β-amilases e fosforilase do amido nos cotilÃdones de plÃntulas cultivadas em Ãgua destilada e em soluÃÃes de NaCl com potenciais de solutos de 0,0, -0,4 e -0,8 MPa. A imersÃo das sementes de copaÃba em Ãcido sulfÃrico concentrado/60min à eficiente para embebiÃÃo e superaÃÃo da dormÃncia. O PEG 6.000 e o NaCl atrasam a embebiÃÃo. Nas condiÃÃes estressantes, o NaCl -1,0 MPa nÃo influencia no %G, mas, aumenta oIVG e reduz o TMG a partir do potencial de soluto de -0,6, MPa. O PEG reduz o %G a partir de -0,8 MPa com maior efeito no IVG e TMG, do que NaCl. Sementes de copaÃba possuem 42% de lipÃdios, principal reserva. O potencial de soluto de -0,8 MPa inibe a mobilizaÃÃo de reservas e aumenta os teores de Ãons Na+ e Cl- nos cotilÃdones e eixos embrionÃrios de sementes de copaÃba. A inibiÃÃo da mobilizaÃÃo das reservas causada pelo sal aumenta os teores de aÃÃcares solÃveis nos cotilÃdones e inibe o crescimento das plÃntulas. As sementes de copaÃba apresentam forte resistÃncia à entrada de Ãgua, a qual pode ser anulada com imersÃo em Ãcido sulfÃrico concentrado por 60 min. Para o %G, as sementes testadas sÃo tolerantes ao NaCl em -1,0 MPa e intolerantes ao PEG em potenciais de solutos equivalentes. A germinaÃÃo à menos sensÃvel ao NaCl do que a fase de plÃntula. O NaCl em potenciais de solutos abaixo de -0,4 MPa reduzem o crescimento e desenvolvimento inicial de plÃntulas de copaÃba. As atividades das enzimas do metabolismo dos lipÃdios e do amido sÃo inibidas com o aumento da salinidade. / The objective of this research was to evaluate different techniques for breaking dormancy, the germination under saline conditions and drought, the development of seedlings subjected to different potentials of solutes and NaCl stress conditions relate to the cotyledonary reserve mobilization in seedlings Copaifera langsdorffii. The treatments of over come consisted of immersion in water/24, 48 and 72 h, hot water, 50, 75 C and boiling water/10â, 15â and 20â and H2SO4 (98,08%)/15, 30â and 60â min and control. For stress conditions, the seeds were immersed in 100 ml of NaCl or PEG 6000 with a potential of the solute, [0,0 (control), -0,2, -0,4, -0,6, -0,8 and -1,0 MPa]. The water absorption, was evaluated (168 h) germination percentage (G%), germination speed index (GSI) and mean germination time (MGT). For the mobilization of the reserves were used as the same solute potential with NaCl above. Sowing was on paper germitest and germination in a germination chamber of the BOD at 25 ÂC and photoperiod of 12 h, consisting of five replicates of 25 seeds per treatment. Studies of the effects of NaCl was done in three stages of developing an ED (radicle with 5  2 cm) ED 2 (issuing protophilus) and ED 3 (protophilus expanded), taking as reference quiescent seeds (DE 0). 15 seedlings per replicate were separated into cotyledons and axis. Quantified the dry mass of cotyledons and axis, the levels of lipids, proteins, starch, soluble sugars, amino acids and Na+, K+ and Cl-. We evaluated the activities of enzymes: lipase, the isocitrate lyase, malate synthase, α and β-amylases and starch phosphorylase in the cotyledons of seedlings grown in distilled water and in NaCl solutions with solute potential of -0,4 and -0,8 MPa. The water absorption by seeds copaiba was higher and faster in the treatments with boiling water and sulfuric acid. The PEG 6000 and NaCl delayed the time of soaking, Overall, the immersion in H2SO4 performed best in breaking dormancy. In stressful conditions, NaCl had no influence on %G, however, reduced the (IVG) and increased the TMG, the solute potential of -0,6, -0,8 and -1,0 MPa. PEG reduced the %G in solute potential of -0,8 and -1,0 MPa and had a greater effect on IVG and TMG, compared with NaCl. The seeds were quiescent lipids as the main reserve. The increase in salinity inhibited the mobilization of reserves in the cotyledons of the seeds, especially in the solute potential of -0,8 and -1,0 MPa and increasing the concentrations of Na+ and Cl- in the embryonic axis and cotyledons. Inhibition of the mobilization of reserves caused by salt provided an increase in soluble sugars in the cotyledons, this effect inhibited the growth and seedling development. The activities of enzymes in the metabolism of lipids and of starch phosphorylase were significantly inhibited with increasing salinity, with more effectively inhibited the enzymes of lipid metabolism. The seeds have a strong resist entry of water, the immersion of the seed in concentrated sulfuric acid for 60â is effective to remove the barrier. For %G, the copaiba seeds under conditions that were tested are NaCl-tolerant and intolerant to PEG. The germination is less sensitive than the NaCl seedling stage. The NaCl in solute potential below -0,4 MPa negatively affects the growth and early development of seedlings of copaiba

CoordenaÃÃo de AperfeiÃoamento de NÃvel Superior / A pesquisa foi conduzida em casa de vegetaÃÃo no Campus do Pici da Universidade Federal do CearÃ, no perÃodo de janeiro a marÃo de 2006, com o objetivo de estudar a resposta das culturas da mamona (Ricinus communis L.), gergelim (Sesamum indicum L.) e amendoim (Arachis hypogaea L.) a ciclos de deficiÃncia hÃdrica na fase de crescimento vegetativo. Foi avaliado o comportamento de duas cultivares de cada espÃcie, a saber: amendoim, cultivares PI 165317 (grupo âSpanishâ) e 57422 (grupo VirgÃnia); gergelim, cultivares CNPA-G3 e CNPA-G4 e mamona, cultivares Mirante e BRS 149 Nordestina. As sementes foram semeadas em tubos de PVC com 100 cm de comprimento e 15 cm de diÃmetro, em solo de textura arenosa. As cultivares foram submetidas a dois regimes hÃdricos - irrigaÃÃo diÃria e ciclos de deficiÃncia hÃdrica. Foram determinadas variÃveis relativas Ãs condiÃÃes hÃdricas da planta, trocas gasosas, crescimento da parte aÃrea e crescimento e estratificaÃÃo do sistema radicular. A colheita das plantas ocorreu aos 50, 55, 56 dias apÃs o plantio para as culturas do gergelim, amendoim e mamona, respectivamente. As variÃveis potencial hÃdrico, conteÃdo relativo de Ãgua, transpiraÃÃo foliar, fotossÃntese foliar e condutÃncia estomÃtica foram reduzidas nas trÃs culturas em resposta aos ciclos de deficiÃncia hÃdrica. A relaÃÃo entre a temperatura foliar e a ambiente aumentou em resposta ao estresse aplicado. O uso eficiente de Ãgua nÃo foi alterado nas culturas da mamona e amendoim, apresentando reduÃÃo significativa no gergelim em resposta ao dÃficit hÃdrico. A matÃria seca da parte aÃrea, das raÃzes e total, bem assim o volume radicular foram reduzidos em todas as espÃcies em resposta ao dÃficit hÃdrico. A relaÃÃo raiz/parte aÃrea aumentou em resposta ao estresse hÃdrico nas culturas do amendoim e gergelim, enquanto na mamona essa relaÃÃo permaneceu inalterada. O amendoim apresentou a menor partiÃÃo de matÃria seca para as raÃzes; o gergelim ficou numa posiÃÃo intermediÃria e a mamona destinou a maior proporÃÃo de biomassa para as raÃzes. O amendoim apresentou a maior modificaÃÃo da estratificaÃÃo do sistema radicular em resposta ao dÃficit hÃdrico, com um maior aprofundamento das raÃzes. A mamona apresentou a menor resposta e o gergelim ficou numa posiÃÃo intermediÃria. Independentemente do regime hÃdrico as trÃs culturas apresentaram maior proporÃÃo do sistema radicular nos primeiros 25 cm de solo. O nÃmero de folhas e a Ãrea foliar foram reduzidos nas trÃs espÃcies em resposta ao dÃficit hÃdrico. / A greenhouse research was carried out at the Universidade Federal do CearÃ, Campus do Pici, from January to March 2006, with the objectives of studying the response of castorbean (Ricinus communis L.), sesame (Sesamum indicum L.) and peanut (Arachis hypogaea L.) to cycles of water deficit in the early vegetative growth phase. The following cultivars for each crop were evaluated: peanut cultivars PI 165317 (group Spanish) and 57422 (group Virginia); sesame CNPA G3 and CNPA G4; and castorbean Mirante and BRS 149 Nordestina. The seeds were planted in PVC tubes 100 cm log and 10 cm wide, filled with sand soil. The cultivars received two water regime treatments: daily irrigation and cycles of water stress. Several variables were determined relative to plant water status, gas exchange, top and root growth and root system distribution in the soil profile. Plant harvest was accomplished at 50, 55 and 56 days after planting for sesame, peanut and castorbean, respectively. The variables water potential, relative water content, leaf transpiration, leaf photosynthesis and stomatal conductance were reduced in all three crops in response to water stress. The relation between leaf and ambient temperature increased in response to water stress. The water use efficiency was not affected by the stress imposed in castorbean and peanut. On the other hand, in sesame this variable decreased in response to water stress. Tops, roots and total dry matter as well as the root system volume were reduced in all species in response to water stress. Root shoot ratio increased in response to water stress for sesame and peanut, while for castorbean this relation remained unchanged. Among the crops studied, peanut plants had the smallest dry matter partition to the roots; sesame stayed in an intermediary position and castorbean partitioned the higher proportion of dry matter to roots. Peanut showed a large modification in the root system stratification in response to the water stress, with the increase of proportion of the root system in the deep soil. Castorbean showed the smaller response as far as deepening of the root system and sesame retained an intermediary position. All three crops, no matter the water regime was, had the most proportion of the root system in the first 25 cm layer of soil. The leaf number and leaf area were reduced in the three species in response to water stress.

FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / Tropical plant species resist seasonal drought by avoidance or tolerance, keeping or losing leaves, respectively. Since drought resistance is influenced by wood attributes and lignin is a major component of wood, we investigated whether lignin is related to foliar retention time (LR). We selected 22 species, determined the stem lignin content by thioglycolic acid and quantified guaiacyl (G) and syringyl (S) monomers by thioacidolysis and GC-MS analysis. Among these species, we selected 15 species to measure vulnerability to embolism by pneumatic method. In our analyses, were considered measures of wood density, stem water saturation and stem water potential in the dry season, published by other authors. Our analyses showed that there are two ways of surviving drought. A small group of species, for which the lignin does not seem to matter, stores water in the stem and loses leaves right at the end of the rainy season. A large group of species, from early deciduous to evergreens, retains leaves in the dry season for increasingly longer periods the higher the S/G ratio is. Higher values of the S/G ratio allow greater LR by reducing vulnerability to embolism. / EspÃcies de plantas de clima tropical sazonalmente resistem à seca por tolerÃncia ou evitaÃÃo, mantendo ou perdendo folhas, respectivamente. Atributos da madeira estÃo relacionados à resistÃncia à seca e a lignina à um dos principais componentes da madeira. Investigamos se a lignina està relacionada ao tempo de retenÃÃo foliar (LR). Selecionamos 22 espÃcies, determinamos o teor de lignina do caule pelo Ãcido tioglicÃlico e quantificamos os monÃmeros guaiacil (G) e siringil (S) by thioacidolysis e GC-MS analysis. Dentre as espÃcies, selecionamos 15 espÃcies para medir a vulnerabilidade ao embolismo pelo mÃtodo pneumÃtico. IncluÃmos medidas da densidade da madeira, saturaÃÃo de Ãgua no caule e potencial hÃdrico do caule na estaÃÃo seca, publicadas por outros autores. Nossas anÃlises mostraram haver duas maneiras de sobreviver à seca. Um pequeno grupo de espÃcies, para as quais a lignina parece nÃo ter importÃncia, armazena Ãgua no caule e perde folhas logo no final da estaÃÃo chuvosa. Um grande grupo de espÃcies, que vÃo desde decÃduas precoces atà sempre verdes, retÃm folhas na estaÃÃo seca por tempos cada vez mais longos quanto maior a razÃo S/G. Maiores valores da razÃo S/G permitem maior LR por diminuir a vulnerabilidade ao embolismo.

CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior / O fruto do morangueiro (Fragaria x anamassa Duch.) à apreciado no mundo inteiro, sendo o plantio realizado em diversas regiÃes, fato esse que ocorre pela existÃncia de cultivares adaptadas a diferentes climas. PorÃm na regiÃo Nordeste hà um grande desafio aos produtores e pesquisadores, devido principalmente Ãs temperaturas e evapotranspiraÃÃes elevadas e a baixa pluviosidade. Outro desafio à a busca por uma agricultura menos dependente de insumos minerais. Os biofertilizantes apresentam-se como uma importante ferramenta para a produÃÃo vegetal, sendo gerados a partir de produtos naturais obtidos da fermentaÃÃo de materiais orgÃnicos. Em consequÃncia, o objetivo deste trabalho foi de avaliar os efeitos de lÃminas de irrigaÃÃo e doses de biofertilizante bovino de fermentaÃÃo anaerÃbica, sob ambiente protegido do tipo telado, nas condiÃÃes climÃticas de Fortaleza, CearÃ. Para isso, o experimento foi conduzido na EstaÃÃo AgrometeorolÃgica da Universidade Federal do Cearà (UFC), em Fortaleza, no perÃodo de setembro a dezembro de 2012, sob ambiente protegido do tipo telado. O delineamento experimental foi em blocos casualizados em esquema de parcelas subdivididas, em que as lÃminas de irrigaÃÃo foram aplicadas via gotejamento (equivalentes a 33,3; 66,6; 100; 133,3; 166,6 % da evaporaÃÃo medida no tanque classe A, ECA), constituÃndo as parcelas. As quatro doses de biofertilizante bovino (125; 250; 375 e 500 ml semana- planta-Â) foram as subparcelas, com quatro repetiÃÃes. Foram avaliadas as trocas gasosas (fotossÃntese, condutÃncia estomÃtica, transpiraÃÃo e concentraÃÃo interna de CO2; aos 40 e 110 DAT), a biomassa (matÃria seca da raiz, da parte aÃrea e total), as variÃveis de colheita (diÃmetro, comprimento, nÃmero, massa mÃdia dos frutos e produtividade) e de pÃs-colheita (sÃlido solÃveis totais, pH, acidez titulÃvel e relaÃÃo sÃlido solÃveis/acidez titulÃvel). A dose de 375 mL semana- planta- apresenta-se como a melhor dosagem para a cultura do morangueiro no litoral cearense. As funÃÃes geradas para a maioria das variÃveis em funÃÃo das lÃminas de irrigaÃÃo foram polinomiais quadrÃticas, sendo as lÃminas Ãtimas prÃximas a 100% da ECA. A lÃmina de irrigaÃÃo equivalente a 126,92% da ECA e a dose de biofertilizante de 375 mL semana- planta- proporciona o maior desenvolvimento da biomassa. Recomenda-se para uma mÃxima produÃÃo, uma lÃmina de irrigaÃÃo equivalente a 101,35% da ECA e uma dose de biofertilizante de 375 mL semana- planta-Â. / The fruit of the strawberry (Fragaria x anamassa Duch.) Is enjoyed all over the world, with planting accomplished in several regions, a fact that occurs the existence of cultivars adapted to different climates. But in the Northeast there is a big challenge for producers and researchers, mainly due to high temperatures and evapotranspiration and low rainfall. Another challenge is the search for a less dependent on mineral inputs agriculture. Biofertilizers are presented as an important tool for crop production, being generated from natural product obtained from the fermentation of organic materials. In consequence, the aim of this study was to evaluate the effects of irrigation and levels of bovine biofertilizer anaerobic fermentation under protected environment of the screenhouse type, in the climatic conditions in Fortaleza, CearÃ. For this, the experiment was conducted in weather station at the Federal University of CearÃ, Fortaleza, from August to December 2012, protected under the greenhouse type environment. Experimental design was a randomized complete block in a split-plot design in that the irrigation was applied through drip (equivalent to 33.3, 66.6, 100, 133.3, 166.6% of class A evaporation measured in tank, ECA), constituted the main plots. The four levels of cattle biofertilizer (125, 250, 375 and 500 ml plant- week-Â) were the subplots with four replications. Were evaluated gas exchange (photosynthesis, stomatal conductance, transpiration, and internal CO2 concentration; at 40 and 110 DAT), the biomass (dry matter of the roots, shoot and total), the variables of harvest (diameter, length, number,average fruit weight and yield) and postharvest (total soluble solid, pH , titratable acidity and soluble solid ratio / acidity). The dose of 375 mL plant- week- is presented as the best dosage for strawberry culture in CearÃ. The functions generated for most variables depending on irrigation were quadratic polynomial, with the best irrigation depths near in the 100% of ECA. The irrigation depths equivalent to 126.92% of ECA and bovine biofertilizer dose of 375 mL plant- week-Â, provides further development of biomass. It is recommended for maximum production a irrigation depths equivalent to 101.35% of ECA and a bovine biofertilizer dose of 375 mL plant- week-Â.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / In this work were studied diverse physiological mechanisms, as the osmotic adjustment, photosynthesis, including gas exchange and chlorophyll fluorescence parameters, as well the oxidative responses in physic nuts submitted to different abiotic stresses as: salinity, drought and high temperature. The first experiment aimed to study the effects of increase of the NaCl concentrations (0, 25, 50, 75 and 100 mM) in the ions accumulate (Na+, Cl- and K+) and some growth variables, as well evaluate the water state and the principals solutes (organic and inorganic) involved on the osmotic adjustment of physic nuts plants under this stressful condition. Physic nuts plants showed sensibility to salt stress, presenting a reduction by 50% in dry matter from by 47 mM of NaCl concentration during 15-d. This sensibility should be due the leaf Na+ and Cl- high accumulation, associated a strong reduction in the K+ concentration, induced by high Na+ content. On the other hand, physic nuts plants were able osmotic adjust to salinity due a severe decrease on the osmotic potential and increase of leaf water state, principally in the higher NaCl levels. Of the solutes studied, was observed that salt ions (Na+ and Cl-) contributed with the most of the osmotic adjustment, while that the K+ contribution was decreased strongly by NaCl. The glycinebetaine compared to proline was more important to the osmotic adjustment of physic nuts leaves, as in the absence as in presence of different NaCl levels in the nutrient solution. The second experiment evaluated the resistance of photosynthetic apparatus of physic nuts plants submitted to different time of exposure (7-d and 14-d of treatment and 3-d of recovery) to salt stress (100 mM of NaCl).The changes caused on photochemistry activity and leaf gas exchange were evaluate by Na+ and Cl- accumulation and decrease of K+/Na+ ratio in the leaves. After 7-d of treatment was observed a major action of osmotic effects. However, after 14-d of treatment, the ionic effects caused by Na+ and Cl- excessive accumulation and by K+/Na+ ratio strong reduction in the leaves, caused permanent damages on the photosynthesis of physic nuts plants due as the stomatal limitations as non-stomatal ones. The third experiment aimed to study the comparative effects between the salt stress (50 mM of NaCl) and water stress (induced for PEG 6000), both with osmotic potential of â0.22 MPa on the photosynthesis, water relations and growth of physic nuts plants. The water stress effects induced for PEG in the leaf growth, electrolyte leakage and leaf gas exchange were more deleterious than by NaCl ones. In the both stresses was observed decrease in the leaf CO2 assimilation due the stomatal and non-stomatal limitations. However, the chlorophyll fluorescence parameters did not affect. The fourth experiment aimed to evaluate the relative contribution of organic and inorganic solutes on the osmotic adjustment of leaves and roots physic nuts plants in different water restriction levels. Of the solutes studied, the K+ and soluble sugar were the most involved in the osmotic adjustment as in the leaves as in roots. Others solutes as, Na+, Cl-, total amino acids and glycibetaine, also presented a effective role in the reduction of osmotic potential in both organs. On the other hand, the leaf proline content, although has increased significantly, was not sufficient to promote an effective participation of this amino acid in the osmotic adjustment of physic nuts plants. The same experiment aimed to observe the isolated and combined effects of water stress and high temperature on the photosynthesis and evaluate the oxidative defenses system in physic nuts plants. The photosynthetic apparatus was more sensitive to water stress than heat ones, been that the combination of them caused deleterious effects yet large in this complex. Additionally, the oxidative damages also were more marked in the combined stress. In general, the data shown that physic nuts plants, although present ability to adjust osmotically to salinity and drought, have their photosynthetic apparatus very affected in this stressful conditions. Even as, the defense system against oxidative damages appears has not been efficient in plants exposure at the drought and heat isolated and combined stresses / In this work were studied diverse physiological mechanisms, as the osmotic adjustment, photosynthesis, including gas exchange and chlorophyll fluorescence parameters, as well the oxidative responses in physic nuts submitted to different abiotic stresses as: salinity, drought and high temperature. The first experiment aimed to study the effects of increase of the NaCl concentrations (0, 25, 50, 75 and 100 mM) in the ions accumulate (Na+, Cl- and K+) and some growth variables, as well evaluate the water state and the principals solutes (organic and inorganic) involved on the osmotic adjustment of physic nuts plants under this stressful condition. Physic nuts plants showed sensibility to salt stress, presenting a reduction by 50% in dry matter from by 47 mM of NaCl concentration during 15-d. This sensibility should be due the leaf Na+ and Cl- high accumulation, associated a strong reduction in the K+concentration, induced by high Na+ content. On the other hand, physic nuts plants were able osmotic adjust to salinity due a severe decrease on the osmotic potential and increase of leaf water state, principally in the higher NaCl levels. Of the solutes studied, was observed that salt ions (Na+ and Cl-) contributed with the most of the osmotic adjustment, while that the K+contribution was decreased strongly by NaCl. The glycinebetaine compared to proline was more important to the osmotic adjustment of physic nuts leaves, as in the absence as in presence of different NaCl levels in the nutrient solution. The second experiment evaluated the resistance of photosynthetic apparatus of physic nuts plants submitted to different time of exposure (7-d and 14-d of treatment and 3-d of recovery) to salt stress (100 mM of NaCl).The changes caused on photochemistry activity and leaf gas exchange were evaluate by Na+ and Cl- accumulation and decrease of K+/Na+ ratio in the leaves. After 7-d of treatment was observed a major action of osmotic effects. However, after 14-d of treatment, the ionic effects caused by Na+ and Cl- excessive accumulation and by K+/Na+ ratio strong reduction in the leaves, caused permanent damages on the photosynthesis of physic nuts plants due as the stomatal limitations as non-stomatal ones. The third experiment aimed to study the comparative effects between the salt stress (50 mM of NaCl) and water stress (induced for xv PEG 6000), both with osmotic potential of â0.22 MPa on the photosynthesis, water relations and growth of physic nuts plants. T e water stress effects induced for PEG in the leaf growth, electrolyte leakage and leaf gas exchange were more deleterious than by NaCl ones. In the both stresses was observed decrease in the leaf CO2 assimilation due the stomatal and nonstomatal limitations. However, the chlorophyll fluorescence parameters did not affect. The fourth experiment aimed to evaluate the relative contribution of organic and inorganic solutes on the osmotic adjustment of leaves and roots physic nuts plants in different water restriction levels. Of the solutes studied, the K+ and soluble sugar were the most involved in the osmotic adjustment as in the leaves as in roots. Others solutes as, Na+, Cl-, total amino acids and glycibetaine, also presented a effective role in the reduction of osmotic potential in both organs. On the other hand, the leaf proline content, although has increased significantly, was not sufficient to promote an effective participation of this amino acid in the osmotic adjustment of physic nuts plants. The same experiment aimed to observe the isolated and combined effects of water stress and high temperature on the photosynthesis and evaluate the oxidative defenses system in physic nuts plants. The photosynthetic apparatus was more sensitive to water stress than heat ones, been that the combination of them caused deleterious effects yet large in this complex. Additionally, the oxidative damages also were more marked in the combined stress. In general, the data shown that physic nuts plants, although present ability to adjust osmotically to salinity and drought, have their photosynthetic apparatus very affected in this stressful conditions. Even as, the defense system against oxidative damages appears has not been efficient in plants exposure at the drought and heat isolated and combined stresses

FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / Um importante mecanismo de sobrevivÃncia celular, realizada pelas espÃcies vegetais em resposta a situaÃÃes adversas ou estressantes, à o acÃmulo de proteÃnas, principalmente as solÃveis, alÃm de aminoÃcidos e outros compostos nitrogenados. Nesse estudo, foi determinada distribuiÃÃo de compostos nitrogenados durante o estresse tÃrmico nas diversas partes da planta. Pode-se observar que com o aumento da temperatura de 25 ÂC para 45 ÂC, houve maior acumulo da fraÃÃo solÃvel em folhas (40%), enquanto que o aumento na fraÃÃo insolÃvel foi de aproximadamente 20% ao passo que o acÃmulo de prolina foi de cerca de cinco vezes nas folhas de cajueiro enquanto que nas raÃzes este aumento foi de apenas uma vez. A concentraÃÃo de aminoÃcidos livres totais foi elevada tanto nas folhas (5%) como nas raÃzes (9%). O conteÃdo de amÃnio sofreu acrÃscimo tanto nas raÃzes (30%) como nas folhas (60%) com a elevaÃÃo da temperatura de 25 ÂC para 45 ÂC. O aumento do conteÃdo de proteÃnas de folhas de cajueiro, induzido pelo calor està relacionado com a mobilizaÃÃo de reservas nitrogenadas a partir de raÃzes e caules e/ou com sÃntese protÃica no tecido foliar. Baseado nessas observaÃÃes, alÃm da deposiÃÃo protÃica durante o estresse tÃrmico, nÃs identificamos padrÃes especÃficos de expressÃo protÃica do cajueiro frente aos estresses abiÃticos isolados e combinados. O padrÃo protÃico de folhas de cajueiro foi comparada por eletroforese bi-dimensional (2D) apÃs os tratamentos: condiÃÃo controle, irrigadas com soluÃÃo Hoagland & Arnon diluÃda a Â, ou submetidas à seca por suspensÃo da rega por 20 dias, e posteriormente tanto as plÃntulas controle como as prÃ-expostas à seca foram submetidas a 25 ÂC ou 45 ÂC. As mudanÃas na expressÃo de proteÃnas foram observadas em 80 proteÃnas de folhas de cajueiro. Na condiÃÃo de calor, 7 proteÃnas aumentaram sua expressÃo e 3 foram aparentemente sintetizadas de novo. Na condiÃÃo de seca, 10 proteÃnas aumentaram sua expressÃo e 2 proteÃnas foram identificadas como plastocianina e ferredoxina. A anÃlise tambÃm mostrou que 17 proteÃnas foram modificadas pelo efeito da combinaÃÃo dos estresses e assim como no estresse tÃrmico, 14 proteÃnas aumentaram sua expressÃo e 2 foram encontradas somente na combinaÃÃo dos estresses. Assim, nossos resultados sugerem que a combinaÃÃo dos estresses deve ser considerada como um novo estado de estresse abiÃtico em plantas, e nÃo simplesmente uma combinaÃÃo de fatores abiÃticos / An important mechanism for survival cell, carried out by the plant species response to adverse or stressful situations, is the accumulation of proteins,especially the soluble proteins as well as amino acids and other nitrogen compounds. In this study, was determined distribution of nitrogen compounds during heat stress in different parts of the plant. It can be observed that with increasing temperature of 25 ÂC to 45 ÂC, there was greater accumulation of soluble fraction in leaves (40%), while the increase in the insoluble fraction was approximately 20% while the accumulation of proline was about five times in the leaves of cashew while this increase in the roots was only once. The concentration of total free amino acids was high both in leaves (5%) and roots (9%). The content of ammonium has increased both in roots (30%) and leaves (60%) with increasing temperature of 25 ÂC to 45 ÂC. Increasing the protein content in the cashew leaves, induced by heat is related to the mobilization of nitrogen reserves from roots and stems and/or protein synthesis in leaf tissue. Based on these observations, in addition to protein deposition during heat stress, we identified specific patterns of protein expression of cashew against specific and combined to abiotic stresses. The protein pattern in cashew leaves was compared by twodimensional electrophoresis (2D) after to the treatments: control conditions, irrigated with Hoagland & Arnon solution diluted to Â, or subjected to drought by suspension of irrigation for 20 days, and then both the control seedlings as the pre-exposed to drought were subjected to 25 ÂC or 45 ÂC. The protein expression changes were in 80 proteins leaves of cashew. In the condition of heat, 7 protein increased the expression and 3 proteins were apparently synthesized de novo. In dry condition, 10 proteins increased their expression and 2 proteins were identified as plastocyanin and ferredoxin. The analysis also showed that 17 proteins were altered by the effect of the stress combination and as well as heat stress, 14 increased expression and 2 were found only in the stress combination. Thus, our results suggest that the stresses combination should be considered as a new state of abiotic stress in plants, and not only as a combination of abiotic factors

FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / A cana-de-aÃÃcar à uma planta de grande potencial econÃmico, sendo utilizada principalmente para produÃÃo de aÃÃcar e biocombustÃveis. O Brasil tem destaque internacional na produÃÃo de cana-de-aÃÃcar, sendo o maior produtor mundial dessa cultura. Apesar dessa lideranÃa, o Brasil està localizado em uma regiÃo tropical e apresenta vÃrias adversidades climÃticas. O estudo da fisiologia da cana-de-aÃÃcar em situaÃÃes de estresse, como deficiÃncia hÃdrica, torna-se fundamental para manutenÃÃo e melhoria da produÃÃo dessa cultura. A cana-de-aÃÃcar à uma espÃcie de fotossÃntese C4, com um mecanismo de concentraÃÃo de CO2. Dessa maneira, espera-se que a crescente elevaÃÃo de CO2 na atmosfera nÃo afete a produtividade da cana-de-aÃÃcar de maneira relevante, mas os estudos acerca do assunto sÃo ainda bem escassos. Diante desse quadro, objetivou-se avaliar a regulaÃÃo da fotossÃntese por deficiÃncia hÃdrica, suprimento de nitrogÃnio e CO2 elevado em plantas de cana-de-aÃÃcar. O CapÃtulo 1 comtempla o estado da arte a respeito do tema em estudo. No capÃtulo 2, foi realizado um trabalho com o objetivo de avaliar as respostas de duas cultivares de cana-de-aÃÃcar consideradas contrastantes em relaÃÃo Ãs respostas à deficiÃncia hÃdrica, IAC SP 94-2094 e IAC SP 95-5000. Estas cultivares foram expostas a dÃficit hÃdrico severo, com suspensÃo da irrigaÃÃo por cinco dias, e recuperaÃÃo, reirrigadas por dois dias apÃs o estresse. O tratamento aplicado foi capaz de afetar fortemente as trocas gasosas, com fechamento estomÃtico nas duas cultivares, levando a fortes reduÃÃes de transpiraÃÃo e assimilaÃÃo de CO2. Os parÃmetros da fluorescÃncia da clorofila a foram afetados, mas nÃo o suficiente para apresentar fotoinibiÃÃo. A cultivar tolerante apresentou maior atividade de PEPcase no estresse, mas a atividade de Rubisco nÃo foi alterada. Na cultivar sensÃvel, nÃo houve alteraÃÃo na atividade de PEPcase enquanto que a atividade de Rubisco foi reduzida em 40% no estresse mas com total recuperaÃÃo. A expressÃo de PEPcase foi aumentada no estresse mas com maior incremento na cultivar tolerante, com padrÃo semelhante na quantidade de rubisco. No capÃtulo 3, foi realizado um trabalho com o objetivo de avaliar o sistema de defesa anti-oxidativo em plantas de cana-de-aÃÃcar expostas ao estresse hÃdrico moderado. Neste capÃtulo, apenas a cultivar IAC SP 94-2094 foi utilizada e a deficiÃncia hÃdrica foi aplicada atravÃs de ciclos de irrigaÃÃo, com plantas irrigadas a cada cinco dias por um perÃodo de 15 dias e recuperaÃÃo de trÃs dias. O estresse hÃdrico aplicado causou reduÃÃes marcantes na condutÃncia estomÃtica, na transpiraÃÃo foliar e na fotossÃntese lÃquida, com recuperaÃÃo parcial, refletindo em uma menor eficiÃncia do uso da Ãgua e eficiÃncia de carboxilaÃÃo. Os parÃmetros fotoquÃmicos apresentaram modificaÃÃes transitÃrias, completamente revertidas pela recuperaÃÃo. As atividades da Rubisco e PEPcase nÃo mostraram modificaÃÃes, mas houve aumento na quantidade relativa de PEPcase e estado de ativaÃÃo da Rubisco. O estresse hÃdrico aplicado aumentou a peroxidaÃÃo lipÃdica e o conteÃdo de H2O2, induzindo aumentos de atividades de SOD e APX, principalmente APX tilacoidal e Fe-SOD. O perfil de aÃÃcares foi alterado nas plantas estressadas, com aumento de hexoses e diminuiÃÃo do teor de amido nas folhas. O objetivo do capÃtulo 4 foi avaliar as modificaÃÃes fisiolÃgicas e bioquÃmicas em relaÃÃo aos processos fotossintÃticos em cana-de-aÃÃcar submetida a um ambiente de elevado CO2 e baixo suprimento de nitrogÃnio (-N). A fotossÃntese lÃquida foi reduzida nas plantas com CO2 elevado e -N. Os parÃmetros fotoquÃmicos foram reduzidos apenas no tratamento -N, mas sem sinal de fotoinibiÃÃo. As enzimas da carboxilaÃÃo, PEPcase e Rubisco, sofreram regulaÃÃes diferenciadas, tanto pelo alto CO2 como pelo baixo suprimento de nitrogÃnio. A determinaÃÃo de nitrato mostrou acÃmulo nas raÃzes, indicando deficiÃncia no transporte para parte aÃrea. O tratamento âN diminuiu o conteÃdo de aminoÃcidos, proteÃnas solÃveis e nitrogÃnio total. O teor de sacarose foi reduzido em todos os tratamentos. Por fim, verificamos que a cultivar IAC SP 94-2094 possui maior fotoproteÃÃo indicada pelo maior NPQ e possui ainda maior atividade e expressÃo de PEPcase, permitindo melhor performance em perÃodos de dÃficit hÃdrico severo. Quando estudada com dÃficit hÃdrico moderado, as plantas desta cultivar apresentaram uma organizada defesa anti-oxidativa para proteÃÃo contra as espÃcies reativas de oxigÃnio. Quando sob elevada concentraÃÃo de CO2, as plantas de cana-de-aÃÃcar exibem modificaÃÃes estomÃticas e bioquÃmicas, reduzindo a atividade fotossintÃtica pela reduÃÃo da assimilaÃÃo de nitrato e atividade de redutase do nitrato, mostrando uma forte relaÃÃo entre a assimilaÃÃo de carbono e nitrogÃnio. / Sugarcane is plant of great economic potential, mainly utilized to sugar and biofuel production. Brazil has an international importance, leading the world production of this culture. In despite of this high production, Brazil is located in a tropical region and presents several climatic adversities. The study of sugarcane physiology in stress situations, like water deficit, becomes essential to maintenance and improvement of the production. Sugarcane is a C4 species, with a CO2 concentration mechanism. It is expected that the growing elevation of CO2 in the atmosphere does not the sugarcane productivity in a relevant way but the studies about this subject are very scarce. Thus, it was aimed to evaluate the photosynthesis regulation by water deficit, nitrogen supply and high CO2 in sugarcane plants. Chapter 1 contains the state of the art concerning the study theme. In the chapter 2, it was performed an work in order to evaluate the responses to water deficit of two sugarcane cultivars considered contrasting about water deficit, IAC SP 94-2094 and IAC SP 95-5000. These cultivars were exposed to severe water deficit, with withholding water for five days, and recovery, irrigated after for two days after stress. The applied treatment strongly affected the gas exchanges, with stomatal closure in both cultivars, leading to great reductions in transpiration and CO2 assimilation. The chlorophyll a fluorescence parameters were affected, but without photoinhibition. Tolerant cultivar showed higher PEPcase activity in stress, but Rubisco activity was not altered. In the sensitive cultivar there was not alteration in the PEPcase activity whereas Rubisco activity was reduced 40% in stress but totally recovered. PEPcase expression was increased in stress but with a higher increment in sensitive cultivar, with a similar pattern in the Rubisco amount. In the chapter 3, it was performed an work in order to evaluate the antioxidative system in sugarcane plants exposed to mild water stress. In this chapter, IAC SP 94-2094 was utilized and the water deficit was applied with irrigation cycles, with plants irrigated each five days for fifteen days and recovery for three days. Water stress applied caused remarkable decreases in the stomatal conductance, leaf transpiration and net photosynthesis, with partial recovery, causing lower water use and carboxylation efficiencies. Photochemical parameters showed transient changes completely reversible by recovery. PEPcase and Rubisco activities did not show modifications but it was increase in the relative amount of PEPcase and Rubisco activation state. Water stress increased the lipid peroxidation and H2O2 content, inducing increases in SOD and APX activities, mainly thylakoidal APX and Fe-SOD. Sugars profile was altered in stressed plants, with increase in hexoses and decrease in starch content in leaves. The aim of the chapter 4 was evaluate the physiological and biochemical changes in concern to photosynthetic processes in sugarcane exposed to high CO2 and low supply of nitrogen (-N). Net photosynthesis was reduced in plants subjected to high CO2 and -N. Photochemical parameters were decreased only in -N treatment, but with no photoinhibition. Carboxylation enzymes, PEPcase and Rubisco, did suffer differential regulations either by high CO2 or by low nitrogen. Nitrate determination showed accumulation in roots, indicating deficiency in transport to shoot. -N treatment decreased the amino acids content, soluble proteins and total nitrogen. Sucrose content was reduced in all treatments. At last, it was verified that IAC SP 94-2094 cultivar has more photoprotection indicated by higher NPQ and more PEPcase activity and expression, conferring a better performance in severe water deficit periods. When studied under mild water stress, the plants showed an organized anti-oxidative defense for protection against reactive oxygen species. When under high CO2, sugarcane plants exhibit stomatal and biochemical changes, reducing the photosynthetic activity by reduction in nitrate assimilation and nitrate reductase activity, showing a strong relation between carbon and nitrogen assimilation.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / Uma questÃo central em ecologia refere-se à distribuiÃÃo e abundÃncia das espÃcies, e como estes atributos sÃo influenciados por fatores biÃticos e abiÃticos. O nicho de regeneraÃÃo expressa os limites de condiÃÃes biÃticas e abiÃticas toleradas e/ou requeridas durante o processo de regeneraÃÃo de uma espÃcie. Esse processo envolve desde a produÃÃo de sementes atà o recrutamento de juvenis, incluindo a dispersÃo e germinaÃÃo de sementes, e estabelecimento de plÃntulas. Qualquer fator que diminua a probabilidade de sobrevivÃncia, em qualquer etapa da regeneraÃÃo, pode reduzir o tamanho da populaÃÃo, sendo este efeito conhecido como gargalo demogrÃfico. Dentro desse contexto, nosso objetivo foi avaliar como fatores biÃticos e abiÃticos podem afetar o processo de regeneraÃÃo inicial em espÃcies da caatinga, sugerindo possÃveis preditores de suas abundÃncias. As espÃcies focais foram Poincianella bracteosa (Tul.) L.P. Queiroz, que apresenta alta densidade de indivÃduos adultos em Ãreas de caatinga e Libidibia ferrea (Mart. ex Tul.) L.P. Queiroz, que possui baixa densidade nessas Ãreas e ocorre, preferencialmente, nas margens de rios temporÃrios. Portanto, a escolha das espÃcies deveu-se ao contraste de abundÃncia entre elas, o que as tornam bons modelos para compreender a relaÃÃo entre nicho de regeneraÃÃo e abundÃncia. No manuscrito I, os fatores estudados foram predaÃÃo prÃ-dispersÃo e dormÃncia de sementes. Os frutos das espÃcies foram coletados em Ãrea de caatinga localizada na Fazenda Experimental Vale do Curu/UFC, no municÃpio de Pentecoste-CE. No experimento de predaÃÃo, realizamos a biometria dos frutos (n=100/espÃcie), em seguida, estes foram beneficiados e as sementes classificadas em trÃs grupos (sadias, mal-formadas e predadas). Para cada espÃcie, calculou-se a taxa de predaÃÃo e contabilizou-se o nÃmero de insetos predadores. No experimento de dormÃncia, as sementes sadias de ambas as espÃcies foram submetidas a seis tratamentos prÃ-germinativos. Ao final do ensaio, calculou-se a porcentagem de germinaÃÃo, Ãndice de velocidade de germinaÃÃo e tempo mÃdio de germinaÃÃo. L. ferrea apresentou maior taxa de predaÃÃo de sementes do que P. bracteosa e baixo potencial de germinaÃÃo, pois, suas sementes possuem tegumento fortemente impermeÃvel à Ãgua. Nossos resultados sugerem que os fatores estudados podem afetar a regeneraÃÃo inicial de L. ferrea e parecem nÃo ter efeitos significativos para P. bracteosa. No manuscrito II, o fator estudado foi o estresse hÃdrico. Avaliamos caracterÃsticas morfolÃgicas e fisiolÃgicas de plÃntulas submetidas a diferentes regimes hÃdricos (10, 40, 70 e 100% da capacidade de campo) durante 85 dias, em casa de vegetaÃÃo localizada na EstaÃÃo MeteorolÃgica/UFC, em Fortaleza-CE. P. bracteosa apresentou caracterÃsticas de espÃcie de baixo-recurso, que conferem vantagens ecolÃgicas em condiÃÃes de estresse, enquanto L. ferrea apesentou caracterÃsticas de espÃcie de alto-recurso. Nossos resultados sugerem que os atributos da âSÃndrome de resistÃncia ao estresseâ podem favorecer a alta abundÃncia de P. bracteosa em Ãreas de caatinga. No manuscrito III os fatores estudados foram o estresse hÃdrico e a herbivoria. Avaliamos o crescimento inicial e a sobrevivÃncia das plantas em condiÃÃes naturais de disponibilidade hÃdrica sazonal e ataque de insetos herbÃvoros, em Ãrea de caatinga localizada na Fazenda Experimental Vale do Curu/UFC. Plantas jovens (dois meses de idade) de ambas as espÃcies foram submetidas a dois tratamentos, controle e inseticida. Mensalmente, foram realizadas medidas de altura, diÃmetro e nÃmero de foliÃlulos durante um ano (abril/2013 - abril/2014). As taxas de crescimento em altura e diÃmetro foram calculadas para diferentes perÃodos: chuvoso/2013, seco/2013 e chuvoso/2014. A herbivoria foi avaliada durante as estaÃÃes chuvosas (2013/2014), contabilizando-se o nÃmero de foliÃlulos com danos causados por insetos. TambÃm foram realizadas medidas de trocas gasosas durante as estaÃÃes chuvosa e seca/2013. As espÃcies nÃo apresentaram diferenÃas significativas nas taxas de crescimento, mas L. ferrea foi mais susceptÃvel à herbivoria e à seca do que P. bracteosa. Nossos resultados sugerem que, durante o estÃgio de planta juvenil, os efeitos do estresse hÃdrico associados aos danos cumulativos da herbivoria podem limitar a regeneraÃÃo natural de L. ferrea em Ãreas de caatinga, sendo os efeitos pouco expressivos na regeneraÃÃo de P. bracteosa. / A central question in ecology refers to the distribution and abundance of species, and how these attributes are influenced by biotic and abiotic factors. The regeneration niche expressed limits biotic and abiotic conditions tolerated and/or required during the regeneration process of a species. This process involves from producing seed until recruitment of juvenile, including seed dispersal, germination, and seedling establishment. Any factor that decreases the probability of survival at any stage of regeneration can reduce the size of the population, and this effect is known as demographic bottleneck. In this context, the aim of this study was to evaluate how biotic and abiotic factors can affect the natural regeneration process and to suggest possible predictors of species abundance. The focal species were Poincianella bracteosa (Tul.) LP Queiroz, who has a high abundance of adults in caatinga areas and Libidibia ferrea (Mart. Ex Tul.) LP Queiroz, who has low abundance in these areas and occurs preferentially on the banks temporary rivers. The choice of species is due to the contrast of abundance between them, which makes them good models for understanding the relationship between regeneration niche and abundance. In the manuscript I, studied factors were pre-dispersal predation and seed dormancy. The fruits were collected in caatinga area located at the Fazenda Experimental Vale do Curu/UFC in the city of Pentecoste-CE. In the predation experiment, conducted biometrics fruits (n=100/species), then fruits have benefited and the seeds were classified into three groups (healthy, malformed and preyed). For each species, we calculated the rate of predation and recorded the number of predator insects. In the dormancy experiment, healthy seeds of both species were subjected to six pre-germinative treatments. At the end of the test, was calculated the germination percentage, germination speed index and average germination time. L. ferrea showed the highest seed predation than P. bracteosa and low germination potential, since its seeds have strongly coat impermeability to water. Our results suggest that the factors can affect the regeneration of L. ferrea and seem to have no significant effects on P. bracteosa. In the manuscript II, the studied factor was water stress. We assess morphological and physiological characteristics of seedlings under different water regimes (10, 40, 70 and 100% of field capacity) for 85 days, in a greenhouse located at the Meteorological Station/ UFC, in the city of Fortaleza-CE. P. bracteosa showed features of species low-resource, which provide ecological benefits in conditions of stress, while L. ferrea showed features of species high-resource. Our results suggest that the attributes of "Stress resistance syndrome" may favor the high abundance of P. bracteosa in areas of caatinga. In the manuscript III the factors studied were water stress and herbivory. We evaluate the initial growth and survival of seedlings under natural conditions of seasonal water availability and attack insect herbivores on caatinga area located at the Fazenda Experimental Vale do Curu/UFC. Seedlings (two months of age) of species were submitted to two treatments, control and insecticide. Monthly, were performed measures of height, diameter and number of leaflets for one year (April/2013 - April/2014). Growth rates in height and diameter were calculated for different periods: rainy/2013, dry/2013 and rainy/2014. The herbivory was conducted during the rainy seasons (2013/2014), counting the number of leaflets with insect damage. Were also conducted measurements of gas exchange during the rainy season and dry/2013. The species showed no significant differences in growth rates, but L. ferrea was more susceptible to herbivory and drought than P. bracteosa. Our results suggest that during the seedling stage, water stress associated with cumulative damage of herbivory may affect the natural regeneration of L. ferrea in areas of caatinga and is little significant in the regeneration of P. bracteosa.