As mudanças climáticas globais, sem dúvida, vêm impactanto muitas culturas de plantas agrícolas e pastagens, afetando potencialmente o crescimento e a produtividade das plantas. Os efeitos significativos podem ser causados pelo aumento das concentrações de CO2 e temperatura no quadro da mudança global. As plantas C3 em termos de fotossíntese e produção de biomassa geralmente respondem positivamente em elevado CO2 atmosférico do que as plantas C4. No entanto, os efeitos do elevado CO2 e do aquecimento podem ser mais complexos do que previsto anteriormente, devido às interações desses fatores. O objetivo deste estudo foi avaliar os efeitos do elevado CO2 (600 ppm) e aquecimento (2 °C de aumento sobre a temperatura ambiente) sobre a fisiologia e bioquímica da forrageira tropical C4 Panicum maximum Jacq. cultivada em um Trop-T-Face (Tropical-Temperature free-air controlled enhancement and free-air carbon dioxide enrichment) sem limitação de água e nutrientes. Foi estimado que o elevado CO2 quando combinado com o aquecimento (eC+eT) aumentou a massa seca do colmo (93%), a biomassa seca total (52%), a área foliar específica (AFE) (12%) e reduziu a razão folha/colmo (30%). Aos 30 dias de experimento, os açúcares solúveis totais das folhas aumentaram com o elevado CO2 (eC) e aquecimento (eT) e depois de 80 dias os açúcares redutores e amido reduziram em eC+eT. Em relação aos carboidratos estruturais, o teor de celulose nas folhas não sofreu variação significativa entre os tratamentos, no entanto, o teor de lignina aumentou em 100% sob eC. Além do incremento em biomassa as plantas foram capazes de evitar fotoinibição do aparato fotossintético e peroxidação lipídica. No tratamento eT os níveis de clorofila aumentaram em 12% e os níveis de -tocoferol reduziram em média de 55%. Os níveis de zeaxantina e luteína, o ciclo de xantofila (VAZ) e o estado de-epoxidação (DPS) do ciclo da xantofila foram alterados pelo elevado CO2 e aquecimento somente depois de 60 dias. Conclui-se que o elevado CO2 e o aquecimento apesar de promoverem uma redução no mecanismo de fotoproteção, a eficiência fotoquímica do fotossistema (PSII) não é danificada se as plantas são cultivadas em condições de disponibilidade hídrica e sem limitação nutricional. No entanto, apesar do aumento em biomassa com elevado CO2 combinado com aquecimento, o elevado CO2 parece resultar em diminuição da qualidade da forragem. / Global climate change undoubtedly impact many agricultural plant crops and grasslands, potentially affecting plant growth and yield. Significant effects may be caused by increased temperature and CO2 concentrations in the frame of global change. It is generally thought that C3 plants may respond positively to atmospheric CO2 enrichment than C4 plants in terms of photosynthesis and biomass accumulation. However, the effects of elevated CO2 and warming may be more complex than previously anticipated due to interactions between these factors. The aim of this study was to evaluate the effects of elevated CO2 (600 ppm) and warming (2 °C increase above ambient temperature) over physiology and biochemistry of the tropical C4 forage Panicum maximum Jacq. grown in a Trop-T-FACE (Tropical-Temperature free-air controlled enhancement and free-air carbon dioxide enrichment) facility under well-watered conditions without nutrient limitation. The combination of elevated CO2 and warming (eC+eT) increased stem dry weight (93%), total dry biomass (52%), specific leaf area (SLA) and decreased the ratio leaves/stem (30%). After 30 days of experiment, total soluble sugar of leaves increased under elevated CO2 (eC) and warming (eT) and carbohydrate sugars and starch decreased in elevated CO2 combined with warming, after 80 days. Regarding structural carbohydrates, cellulose content in leaves had no significant variation between treatments, however, lignin content increased 100% under eC. Furthermore, beyond increase in biomass, plants were able to avoid photoinhibition of the photosynthetic apparatus and lipid peroxidation in response to elevated CO2 and warming. In treatment eT chlorophyll levels increased by 12% and -tocopherol levels decreased by 55%. The de-epoxidation state (DPS) of the xanthophyll cycle, an indicator of excess energy dissipation as heat, xanthophyll cycle pool (VAZ) and both zeaxanthin and lutein levels were changed by elevated CO2 and warming only after 60 days. We conclude that the elevated CO2 and warming while promoting a reduction in photoprotection mechanism, the photochemical efficiency of photosystem (PSII) is not damaged if plants are grown under well-watered and adequate nutritional conditions. However, despite growth increase with elevated CO2 combined warming, elevated CO2 appears to result in decreased quality of forage.

As mudanças climáticas globais, sem dúvida, vêm impactanto muitas culturas de plantas agrícolas e pastagens, afetando potencialmente o crescimento e a produtividade das plantas. Os efeitos significativos podem ser causados pelo aumento das concentrações de CO2 e temperatura no quadro da mudança global. As plantas C3 em termos de fotossíntese e produção de biomassa geralmente respondem positivamente em elevado CO2 atmosférico do que as plantas C4. No entanto, os efeitos do elevado CO2 e do aquecimento podem ser mais complexos do que previsto anteriormente, devido às interações desses fatores. O objetivo deste estudo foi avaliar os efeitos do elevado CO2 (600 ppm) e aquecimento (2 °C de aumento sobre a temperatura ambiente) sobre a fisiologia e bioquímica da forrageira tropical C4 Panicum maximum Jacq. cultivada em um Trop-T-Face (Tropical-Temperature free-air controlled enhancement and free-air carbon dioxide enrichment) sem limitação de água e nutrientes. Foi estimado que o elevado CO2 quando combinado com o aquecimento (eC+eT) aumentou a massa seca do colmo (93%), a biomassa seca total (52%), a área foliar específica (AFE) (12%) e reduziu a razão folha/colmo (30%). Aos 30 dias de experimento, os açúcares solúveis totais das folhas aumentaram com o elevado CO2 (eC) e aquecimento (eT) e depois de 80 dias os açúcares redutores e amido reduziram em eC+eT. Em relação aos carboidratos estruturais, o teor de celulose nas folhas não sofreu variação significativa entre os tratamentos, no entanto, o teor de lignina aumentou em 100% sob eC. Além do incremento em biomassa as plantas foram capazes de evitar fotoinibição do aparato fotossintético e peroxidação lipídica. No tratamento eT os níveis de clorofila aumentaram em 12% e os níveis de -tocoferol reduziram em média de 55%. Os níveis de zeaxantina e luteína, o ciclo de xantofila (VAZ) e o estado de-epoxidação (DPS) do ciclo da xantofila foram alterados pelo elevado CO2 e aquecimento somente depois de 60 dias. Conclui-se que o elevado CO2 e o aquecimento apesar de promoverem uma redução no mecanismo de fotoproteção, a eficiência fotoquímica do fotossistema (PSII) não é danificada se as plantas são cultivadas em condições de disponibilidade hídrica e sem limitação nutricional. No entanto, apesar do aumento em biomassa com elevado CO2 combinado com aquecimento, o elevado CO2 parece resultar em diminuição da qualidade da forragem. / Global climate change undoubtedly impact many agricultural plant crops and grasslands, potentially affecting plant growth and yield. Significant effects may be caused by increased temperature and CO2 concentrations in the frame of global change. It is generally thought that C3 plants may respond positively to atmospheric CO2 enrichment than C4 plants in terms of photosynthesis and biomass accumulation. However, the effects of elevated CO2 and warming may be more complex than previously anticipated due to interactions between these factors. The aim of this study was to evaluate the effects of elevated CO2 (600 ppm) and warming (2 °C increase above ambient temperature) over physiology and biochemistry of the tropical C4 forage Panicum maximum Jacq. grown in a Trop-T-FACE (Tropical-Temperature free-air controlled enhancement and free-air carbon dioxide enrichment) facility under well-watered conditions without nutrient limitation. The combination of elevated CO2 and warming (eC+eT) increased stem dry weight (93%), total dry biomass (52%), specific leaf area (SLA) and decreased the ratio leaves/stem (30%). After 30 days of experiment, total soluble sugar of leaves increased under elevated CO2 (eC) and warming (eT) and carbohydrate sugars and starch decreased in elevated CO2 combined with warming, after 80 days. Regarding structural carbohydrates, cellulose content in leaves had no significant variation between treatments, however, lignin content increased 100% under eC. Furthermore, beyond increase in biomass, plants were able to avoid photoinhibition of the photosynthetic apparatus and lipid peroxidation in response to elevated CO2 and warming. In treatment eT chlorophyll levels increased by 12% and -tocopherol levels decreased by 55%. The de-epoxidation state (DPS) of the xanthophyll cycle, an indicator of excess energy dissipation as heat, xanthophyll cycle pool (VAZ) and both zeaxanthin and lutein levels were changed by elevated CO2 and warming only after 60 days. We conclude that the elevated CO2 and warming while promoting a reduction in photoprotection mechanism, the photochemical efficiency of photosystem (PSII) is not damaged if plants are grown under well-watered and adequate nutritional conditions. However, despite growth increase with elevated CO2 combined warming, elevated CO2 appears to result in decreased quality of forage.

Chickpea (Cicer arietinum) is an important legume crop globally ranked third after dry bean (Phaseolus vulgaris) and field pea (Pisum sativum). It constitutes 20% of the total global pulse production and around 95% of its production and consumption takes place in developing countries. Major constraints to chickpea production in sub Saharan Africa (SSA) have broadly been related to abiotic stresses, particularly drought and heat stresses, predicted to increase due to the global climatic changes.Dueto the imperativeness of research for identifying heat tolerance markers for potential chickpea genotype selection, in chapter two of the thesis, the response of four chickpea genotypes to a natural temperature gradient in the field was assessed using chlorophyll fluorescence, non-structural carbohydrate, gas exchange and grain yield. Field experiments were carried out in two winter seasons at three locations with known differences in temperature in NE South Africa. Results showed two genotypes (Acc#3 and Acc#7) were tolerant to heat stress with an Fᵥ/Fₘ of 0.83-0.85 at the warmer site, while the two sensitive genotypes (Acc#RR-2 and Acc#8) showed lower Fᵥ/Fₘ of 0.78-0.80. Both chlorophyll fluorescence measurements: dark-adapted Fᵥ/Fₘ and Fq'/Fₘ' (where Fq' =Fₘ'–F) measured at comparable high light levels correlated positively with grain yield. The two tolerant genotypes also showed higher photosynthetic rates,starch, sucrose and grain yield than the sensitive genotypes at the warmer site. However, these parameters were consistently higher at the cooler than at the warmer sites. It was concluded that genotypes Acc#RR-3 and Acc#7 are heat tolerant and chlorophyll fluorescence and leaf carbohydrates are suitable tools for selection of heat tolerant chickpea genotypes under field conditions. The coolest site of Polokwane showed favourable conditions for chickpea production.Heat and drought stresses are two abioticfactors that often occur simultaneously and are predicted to increase, consequently hampering plant growth. Response of different species to either stresses is well documented but information on the response of the same genotypes to both stresses in chickpea is limited. We aimed to determine whether previously noted heat stress tolerant genotype (Acc#7) is drought tolerant and the heat sensitive (Acc#8) is drought sensitive, and whether intermittent moisture supply at vegetative stage would induce priming effect to later drought at flowering. At vegetative stage, plants were divided into three groups, non-stressed (watered to 75% field capacity (FC), severe water stress (moisture-withholding for 14 days) and treated to 40% FC throughout the experiment (mild-stress), with recovery for the severely stressed plants after which they were stressed (double-stress) at flowering. Drought treatments at vegetative and flowering growth stages decreased physiological parameters and biomass accumulation in both genotypesexcept low water supply at 40% FC that decreased biomass in Acc#7 but not Acc#8. Double drought stress resulted in priming effect in Acc#7, having higher biomass, chlorophyll fluorescence, stomatal conductance, net photosynthesis, and relative water content in comparison to the introduction of stress only at flowering growth stage, as well as in comparison to Acc#8. These results showed that both Acc#7 and Acc#8 are sensitive to drought whereas after priming Acc#7 is better acclimated to drought than Acc#8 associated with osmotic adjustment on leaf relative water content (RWC) and higher capacity to protect photosynthetic activity, making Acc#7 potentially ideal for areas associated with intermittent drought spells. This observation, however, disapproved the hypothesis that Acc#7 is more drought tolerant than Acc#8 but is rather better acclimated than Acc#8, because of its superiority only in primed plants and not those stressed only at either vegetative or flowering stages. The findings emphasise the importance of matching chickpea physiological performance to expected rainfall amounts and distribution in drought prone areas during genotype selection. Chapter four of the thesis was an interrogative proteome analysis of the differences in the heat tolerant and sensitive chickpea (Cicer arietinumL.; Fabaceae) genotypes along a temperature gradient under field conditions which will help in identifying the molecular mechanisms involved in the crop's tolerance. Few studies have thus far combined chickpea physiological and proteome analysis to elucidate the changes in abundance and/or activity of relevant enzymes and expression of heat responsive proteins. In this study, analyses of chlorophyll concentrations, gas exchange, flavonoids and anthocyanin concentrations from a chamber experiment, as well as proteomic parameters from field studies in both the heat tolerant and sensitive genotypes are presented. The heat tolerant genotype Acc#7 maintained unaltered physiological performance at flowering growth stage when exposed to high (35/30°C) and moderate (30/25°C) heat stress, under climate chamber conditions compared to the two heat susceptible genotypes (Acc#RR-2 and Acc#8). Results from the proteomic studies showed an up-regulation in proteins related to protein synthesis (e.g. ribulose bisphosphate carboxylase/oxygenase activase), intracellular traffic (e.g. mitochondrial dicarboxylate/tricarboxylate transporter DTC), defence (e.g. HSP70) and transport (e.g. GTP-binding protein SAR1A-like) in heat tolerant Acc#7 compared to the susceptible Acc#8. Results from KEGG analyses support the involvement of probable sucrose-phosphate synthase and sucrose-phosphate phosphatase proteins in the starch and sucrose pathway,that were up-regulated in the heat tolerant genotype Acc#7. This result was in support of our earlier report where tolerant genotype Acc#7 had higher leaf starch and sucrose concentrations in comparison to the susceptible genotype Acc#8. The presence of these differentially regulated proteins including HSP70, ribulose bisphosphate carboxylase/oxygenase activase, plastocyanin and protoporphyrinogen oxidase shows their potential role in field grown chickpea tolerance to heat stress at flowering growth stage. In conclusion, chlorophyll fluorescence (both Fᵥ/Fₘ and Fq'/Fₘ') and leaf carbohydrates were identified as selection markers that can potentially be used for chickpea phenotyping for heat stress under field conditions with the chlorophyll fluorescence parameters correlating positively with seed yield. Due to its higher biomass, chlorophyll fluorescence (Fᵥ/Fₘ), stomatal conductance, net photosynthesis and RWC, heat tolerant genotype Acc#7 was identified to have better adaptive tolerance to drought stress after priming through exposure to intermittent dry spells than Acc#8. Furthermore, under controlled climate chamber conditions, Acc#7 consistently showed characteristics of tolerance to heat stress while Acc#RR-2 and Acc#8 were heat susceptible. Higher chlorophyll fluorescence, grain yield, chlorophyll concentrations, gas exchange, flavonoids and anthocyanin concentrations for Acc#7 compared to Acc#8 in the climate chamber was further validated by the higher up-regulation of proteins involved in protein synthesis, intracellular traffic, defence and transport in Acc#7 compared to Acc#8. The incorporation of proteomics in heat and drought stress studies will potentially help further the understanding of mechanisms by which the crop responds to these stresses.

Pachycoris torridus (Scopoli, 1772) (Hemiptera: Scutelleridae) is the only representative of the Scutelleridae family of agricultural impact in Brazil. This bug is the main pest of Jatropha curcas (Linnaeus) (Euphorbiaceae), which produces raw material for the production of biodiesel. This study has as objective to evaluate bioecological and chemical aspects of P. torridus in herbivory of J. curcas. The experiments were performed using different methodologies, filed in literature, adapted to the particular insect pest, besides the development of new methodology that evaluated the attractiveness of J. curcas in different direction and distance. The research was developed in the Chemistry Laboratory of Natural Products of the Federal University of Alagoas (LPqRN/UFAL) and in Physiology Laboratory of the Agrarian Science Center (CECA/UFAL) and in the field (in the cities of Maceio and Rio Largo) during the period of May 2011 to January 2015. Younger seedlings were more susceptible to the attack even with smallest infestation, which the pest control must be done when there are signs of infestation in this stage. The sequence of behavioral categories which induced the sexual receptivity before intercourse was described in twelve steps. The intraspecific communication of P. torridus was brokered by emission of compound volatiles within a short distance, vibrational signals, sound and groping, driven by the male and recognized by the female. To make a difference between the patterns already known, the 30 new color patterns can be included in literature records, from number 28 to 57. Jatropha curcas releases kairomones long distances (200m) which isolatedly attracts P. torridus for hosting and herbivory. In the chemical evaluations, the compounds identified in the cuticle of P. torridus were: (E)-2-hexenal, (E)-4-(oxo)-2-hexenal, (E)-2-hexenyl acetate, (E)-2-octenal, undecane, dodecane, 1-tridecene, tridecane, (Z,Z)-2,7-Octadien-1-ol acetate, tetradecane and tetradecanal. Species adults P. torridus release content from metathoracic glands during courtship and copulation to attract the opposite sex, being able to empty their reservoir. That bug doesn’t secrete sexual pheromone and contents of their metathoracic glands submit double behavioral activity (alarm and attractiveness) at different concentrations. The rejection of the males to the females with new color patterns was caused by the presence of the chemical compound 1-Tridecene, as well as by increasing the concentration of the compound (E)-2-Octenal. / Fundação de Amparo a Pesquisa do Estado de Alagoas / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Pachycoris torridus (Scopoli, 1772) (Hemiptera: Scutelleridae) é o único representante da família Scutelleridae de impacto agrícola no Brasil. Esse percevejo é a principal praga da Jatropha curcas (Linnaeus) (Euphorbiaceae), a qual produz matéria-prima para obtenção de biodiesel. O presente trabalho visa avaliar aspectos bioecológicos e químicos de P. torridus na herbivoria de J. curcas. Os experimentos foram realizados por meio de variadas metodologias, protocoladas na literatura, adaptadas as particularidades do inseto-praga, além do desenvolvimento de nova metodologia que avaliou a atratividade de J. curcas em diferentes direção e distância. As pesquisas foram desenvolvidas no Laboratório de Química de Produtos Naturais da Universidade Federal de Alagoas (LPqRN/UFAL), no Laboratório de Fisiologia do Centro de Ciências Agrárias (CECA/UFAL) e no campo (em Maceió e Rio Largo), no período de maio de 2011 a janeiro de 2015. Mudas mais jovens foram mais suscetíveis ao ataque, mesmo com menor infestação, devendo ser feito o controle da praga quando ocorrerem sinais de infestação nessa fase. A sequência de categorias comportamentais que induziu a receptividade sexual antes da cópula foi descrita em doze etapas. A comunicação intraespecífica de P. torridus foi intermediada por emissão de compostos voláteis a curta distância, sinais vibratórios, sonoro e de tateamento, impulsionada pelo macho e reconhecida pela fêmea. Para diferenciar dos padrões já conhecidos, os 30 novos padrões cromáticos podem ser incluídos nos registros da literatura, a partir do no28 até 57. A espécie J. curcas emite cairomônios a longa distâncias (200m) que atraem isoladamente P. torridus para hospedagem e herbivoria. Nas avaliações químicas os compostos identificados na cutícula de P. torridus foram: (E)-2-Hexenal, (E)-4-(oxo)-2-Hexenal, Acetato de (E)-2-hexenila, (E)-2-Octenal, Undecano, Dodecano, 1-Trideceno, Tridecano, Acetato de (Z,Z)-2,7-octadien1-ol, Tetradecano e Tetradecanal. Adultos da espécie P. torridus liberam conteúdo das glândulas metatorácicas durante a corte e cópula, para atrair o sexo oposto, chegando a esvaziar seu reservatório. Esse percevejo não secreta feromônio sexual e o conteúdo de suas glândulas metatorácicas apresentam dupla atividade comportamental (alarme e atratividade) em concentrações diferentes. A rejeição dos machos as fêmeas com novos padrões cromáticos foi ocasionada pela presença do composto químico 1-Trideceno, bem como pelo aumento na concentração do composto (E)-2-Octenal.

La llegada de plantas exóticas fuera de su rango de distribución original y su posterior asentamiento en ecosistemas naturales no es una excepción en las Islas Baleares. En la actualidad tenemos 308 especies no nativas naturalizadas y subespontáneas que representan el 16% del total de la flora Balear. En esta tesis se ha evaluado el estado de la cuestión a nivel global y local. Se ha confeccionado el primer catálogo de flora introducida y se ha analizado cuales de ellas son más abundantes y peligrosas; así como también qué ecosistemas son más vulnerables a la introducción de éstas. También se ha profundizado en el conocimiento de dos de las especies exóticas más peligrosas en el litoral Balear: Carpobrotus edulis y C. affine acinaciformis. Se ha evaluado su influencia sobre la polinización, su tasa de crecimiento bajo diferentes escenarios ambientales, se ha confeccionado un modelo de crecimiento y se ha evaluado su impacto sobre la composición y estructura de las comunidades nativas. / L'arribada de plantes exòtiques fora del seu rang de distribució original i el seu posterior assentament a ecosistemes naturals no és una excepció a les Illes Balears. A l'actualitat tenim 308 espècies no natives naturalitzades i subespontànies que representen el 16% del total de la flora Balear. En aquesta tesi s'ha avaluat l'estat de la qüestió a nivell global i local. S'ha confeccionat el primer catàleg de flora introduïda i s'han analitzat quines d'elles són més abundants i perilloses; així com també quins ecosistemes són més vulnerables a la introducció d'aquestes. També s'ha profunditzat en el coneixement de dues de les espècies exòtiques més perilloses del litoral Balear: Carpobrotus edulis y C. affine acinaciformis. S'ha avaluat la seva influència damunt els vectors de pol·linització, la taxa de creixement a diferents escenaris ambiental, s'ha confeccionat un model de creixement, i s'ha avaluat el seu impacte damunt la composició i estructura de les comunitats natives. / The constant arrival of exotic plants into areas outside their original distribution range and further settlement in natural ecosystems is not an exception in the Spanish Balearic archipelago. At the moment we have 308 non native species (naturalized and casual), the 16% from the total Balearic flora. This thesis has evaluated the exotic plant problematic at global and local level. We have elaborated the first exotic plants list, its distribution and abundance, as well as its degree of impact on the more vulnerable environments. We went deeply into the knowledge of two very invasive plants along the coast of the Balearic islands: Carpobrotus edulis y C. affine acinaciformis. We have evaluated its influence over pollen transmission, its growth rate at different environmental conditions, we have too elaborated a non liner growth model and its impact on composition and structure in natural communities