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Beltran, Juan David. "Ecological and evolutionary significance of crassulacean acid metabolism in the montane genus Puya (Bromeliaceae)." Thesis, University of Oxford, 2017. https://ora.ox.ac.uk/objects/uuid:fe892c6e-df4e-4900-9a11-6d5b7ca73f22.
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Little is known about the evolution and ecology of crassulacean acid metabolism (CAM) in the genus Puya Molina. CAM is a photosynthetic pathway typified by nocturnal CO2 fixation and is regarded as a water-saving mechanism. Puya is one of the largest genera in the pineapple family (Bromeliaceae), with 226 species distributed across the Andes to Costa Rica and the Guiana Shield, and from sea level to 5000 m. About 21% of Puya species are CAM and at least 10 of these CAM species occur above 3000 m. The main aim of this thesis was to uncover new evidence to understand the ecophysiology and evolution of CAM in the montane genus Puya. The prevalence of CAM and C3 species in Puya was estimated from carbon isotope values of 161 species. The climatic niche of constitutive CAM species and C3 species of Puya was modelled using georeferenced herbarium records and climatic variables to evaluate the differences between their niches. The evolution of CAM in Puya was investigated by reconstructing the ancestral photosynthetic pathway on an AFLP phylogeny and by studying positive selection in the genes encoding the key enzyme phosphoenolpyruvate carboxylase (PEPC). The coldresistance and the thermal lability of PEPC was investigated for high- and low- elevation CAM species of Puya to explore the potential molecular adaptations of CAM plants in high-elevation environments. The present study concludes that the common ancestor of Puya was a cold-resistant plant. This is suggested to explain the prevalence of Puya at highelevations. The evolution of CAM was correlated with changes in the climatic niche, and occurred multiple times in Puya. These multiple origins were not independent because the common ancestor of Puya was likely to be a weak CAM plant (based on a diagnostic Arg679 residue in the PEPC sequence). It is likely that populations of P. chilensis gained CAM by introgression with P. alpestris ssp. zoellneri. Weak CAM photosynthesis and coldxv resistance allowed Puya to colonise the Andes from the south to the north; and, in the process, constitutive CAM and C3 evolved. The later-evolving species in the genus are suggested to have lost their capacity for CAM as they radiated into more mesic habitats during their colonisation of the northern Andes.
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Bartholomew, Dolores Marie. "Isolation and characterization of genes encoding vacuolar membrane proteins from the CAM plant Kalanchoe daigremontiana." Thesis, University of Oxford, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388961.
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Mioto, Paulo Tamaso. "Sinalização do óxido nítrico sobre a regulação do Metabolismo Ácido das Crassuláceas (CAM) em Guzmania monostachia." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/41/41132/tde-02122016-095125/.
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Guzmania monostachia é uma bromélia-tanque epífita que apresenta uma alta plasticidade fotossintética, sendo capaz de regular positivamente o metabolismo ácido das crassuláceas (CAM) em resposta ao déficit hídrico. Também foi visto para essa espécie que o incremento do CAM se dá de forma diferente ao longo do comprimento da folha, sendo mais intenso na região apical do que na basal. Trabalhos anteriores indicaram que o óxido nítrico (NO) parece estar envolvido na regulação do CAM, mas nada se sabe dos mecanismos pelos quais isso ocorre. Uma vez que parecem não existir receptores específicos de NO, acredita-se que ele seja capaz de se ligar diretamente às proteínas, através de um processo conhecido como nitrosilação. O presente trabalho visou determinar se o NO estaria atuando na regulação do CAM em G. monostachia através da nitrosilação de proteínas relacionadas a esse metabolismo. Para tanto, foram feitos três desenhos experimentais. No primeiro, folhas destacadas de G. monostachia foram mantidas por 7 dias em água (controle) ou em uma solução contendo 30% de PEG (déficit hídrico). Durante esse período, foram monitorados parâmetros indicativos de estresse (porcentagem de água, potencial hídrico, além dos teores de clorofilas, carotenoides e proteínas), CAM (atividade da fosfoenolpiruvato carboxilase - PEPC - e acúmulo noturno de malato e citrato) e emissão de NO. Todas as análises foram feitas nas porções basal e apical das folhas. Ao final dos 7 dias de escassez hídrica, também foram feitas dosagens de nitrosotióis totais e a visualização em gel de proteínas nitrosiladas na porção apical. O segundo experimento visou verificar a modulação da atividade de enzimas pela nitrosilação. Para tanto, extratos proteicos de folhas de G. monostachia foram incubados com glutationa reduzida (GSH) ou S-nitrosoglutationa (GSNO) para, em seguida,verificar diferenças nas atividades das enzimas PEPC, malato desidrogenase (MDH), ascorbato peroxidase (APX), catalase (CAT) e isocitrato desidrogenase dependente de NADP+ (NADP-ICDH). No terceiro experimento foi feita a aplicação do sequestrador de NO 2-(4-carboxifenil)-4,4,5,5-tetrametilimidazolina-1-oxil-3-óxido (cPTIO) ou de NO gasoso em folhas destacadas mantidas em PEG ou água, respectivamente. Os resultados mostraram que o aumento do CAM se dá seis dias após o início do tratamento de déficit hídrico, concomitantemente com o aumento na produção de NO. Esses dois fenômenos ocorreram somente na porção apical da folha. A quantidade de proteínas nitrosiladas, no entanto, diminuiu em resposta ao déficit hídrico nesta porção, indicando que o aumento na emissão de NO pode ser oriundo de uma desnitrosilação de proteínas. De fato, a atividade de três (PEPC, APX e NADP-ICDH) das cinco enzimas analisadas mostraram uma diminuição em resposta ao tratamento com GSNO. Dessa forma, o NO parece não se ligar diretamente às enzimas do CAM para regular sua atividade. Mesmo assim, a aplicação de NO gasoso causou um aumento em todos os parâmetros relacionados ao CAM após 5 dias, sugerindo algum tipo de controle transcricional sobre genes relacionados a esse tipo de fotossínteseGuzmania monstachia is an epiphytic tank-bromeliad capable of up-regulating CAM under water deficit. Moreover, the increase in CAM is stronger in the apical portion of the leaf, when compared to the base. Nitric oxide (NO) is a signaling molecule involved in the regulation of CAM, but the mechanisms underlying this phenomenon are still largely unknown. NO is capable of interacting with proteins through a process known as nitrosylation. Here, we investigated whether NO could regulate CAM by protein nitrosylation. In order to do so, we performed three experiments. In the first one, detached leaves were maintained for 7 days in water or in a solution containing 30% of poliethylene glycol 6000 (PEG). During this period, the water percentage, water potential, contents of chlorophylls and carotenoids, phosphoenolpyruvate carboxylase (PEPC) activity, nocturnal malate and citrate accumulation, and NO emission were monitored daily in the basal and apical portions of the leaf. At the seventh day of the water shortage, quantification of total nitrosothiols and in-gel visualization of nitrosylated proteins were also performed in the apical portion. The second experiment consisted in incubating proteic extracts of G. monostachia with reducedglutathione (GSH) or S-nitrosoglutathione (GSNO) to assess the impact of nitrosylation in enzymatic activity. The enzymes selected to this step were PEPC, malate dehydrogenase (MDH), ascorbate peroxydase (APX), catalase (CAT) and NADP+-dependent isocitrate dehydrogenase (NADP-ICDH). The third experiment consisted in the application of the NO scavenger 2-(4-carboxifenil)-4,4,5,5-tetrametilimidazolina-1-oxil-3-óxido (cPTIO) or gaseous NO to leaves maintained in water or in PEG 30%, respectively. The results show that there was an increase of both CAM and NO in the leaf apex at the sixth day of water deficit. The level of nitrosylated proteins, however, decreased in this portion, indicating that the emission of NO may be the result of a de-nitrosylation process. In fact, the activity of three (PEPC, APX and NADP-ICDH) out of five enzymes analyzed decreased with nitrosylation. Therefore, NO does not regulate directly the activity of CAM enzymes. Nevertheless, exogenous NO increased all of the assayed CAM parameters after 5 days, indicating transcriptional control of CAM-related genes
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Fox, Andrew J. "Physiological Response of Crassulacean Acid Metabolism in Agave Americana to Water and Nitrogen." Ohio University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1559122951997819.
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Mioto, Paulo Tamaso. "Sinalização da indução do metabolismo ácido das crassuláceas (CAM) por ácido abscísico e óxido nítrico em Guzmania monostachia (Bromeliaceae)." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/41/41132/tde-11072012-094636/.
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Guzmania monostachia é uma bromélia tanque epífita C3-CAM facultativa, constituindo-se em um modelo muito interessante para estudar a sinalização que ocorre na transição da fotossíntese C3 para CAM. Baseado em resultados obtidos pelo Laboratório de Fisiologia Vegetal do IBUSP, constatou-se que a mudança em questão se dá de forma diferente ao longo do comprimento das folhas dessa espécie, sendo muito mais pronunciada na região apical do que na basal. Outra pesquisa, desenvolvida anteriormente no mesmo laboratório, sugere fortemente que na indução ao CAM, em plantas jovens de abacaxizeiro C3, o óxido nítrico (NO) e o ácido abscísico (ABA) atuam como mediadores dessa resposta. Levando em conta esses fatos, o presente trabalho visou caracterizar a participação do NO e do ABA como sinalizadores do CAM em uma bromélia que é reconhecidamente C3-CAM facultativa na natureza. Além disso, suas folhas apresentam diferentes níveis de expressão do CAM ao longo do comprimento, podendo, assim, constituir-se em um ótimo modelo para estudos de sinalização. Também se buscou, nesta pesquisa,saber se seria possível reduzir o modelo de estudo para folhas destacadas, não necessitando empregar a planta inteira nos experimentais. Após a comparação da fotossíntese entre folhas pertencentes a plantas inteiras e folhas destacadas, concluiu-se que é viável trabalhar com as folhas isoladas.Essas foram induzidas ao CAM por déficit hídrico, proporcionado por uma solução de polietilenoglicol (PEG) na concentração de 30%. O acúmulo noturno de acidez e a atividade das enzimas fosfoenolpiruvato carboxilase (PEPC) e malato desidrogenase (MDH) em três porções foliares (porção basal, mediana e apical) foram usadas para caracterizar o grau de expressão do CAM. O conteúdo d\'água (expresso em porcentagem)foi usado como um indicativo da perda d\'água pelo tecido foliar.A participação do NO no processo de indução ao CAM foi avaliado por meio de dosagens por quimioluminescência, espectrofluorimetria e localização in situ por microscopia de fluorescência. Também foi usado um doador desse radical livre, o nitroprissiato de sódio (SNP). O ABA foi quantificado pela técnica de cromatografia a gás acoplada a espectrômetro de massas (GC-MS). As folhas mudaram seu metabolismo fotossintético de C3 para CAM no sexto dia de incubação com PEG (segundo o acúmulo noturno de ácidos e a atividade da enzima PEPC), mas a primeira queda detectável no teor d\'água ocorreu logo nas 12 primeiras horas, aumentando até 24ª hora. Nos dias seguintes (até o 7º), o menor teor de água foi encontrado na região basal da folha, enquanto que o CAM se expressou com maior intensidade na porção apical, sugerindo a existência de uma sinalização da redução hídrica entre a parte basal e a apical da folha. De fato, foram detectados maiores quantidades de ABA, em resposta ao déficit hídrico imposto pelo PEG, ao longo de todo o comprimento foliar, com maior quantidade na região apical. Teores significativamente maiores de NO foram detectados por espectrofluorimetria nos últimos três dias de experimento, apenas na região apical. A citolocalização do NO corroborou a quantificação por espectrofluorimetria, mostrando um aumento a partir do sexto dia nos ápices foliares. Conclui-se, portanto, que tanto o NO quanto o ABA parecem participar da sinalização do CAM. Possivelmente, o ABA desempenha um papel decisivo quanto à sinalização da diminuição do teor d\'água, devido ao seu aumento em todo o comprimento da folha,enquanto que o NO parece atuar como um mensageiro secundário, importante à indução do CAM na porção apical foliar.Guzmania monostachia is a C3-CAM facultative epiphyte tank bromeliad and a very promising model to study the C3 to CAM transition. Results obtained on the Laboratory of Plant Physiology on IBUSP showed that this transition occurs differently along the leaf blade o this species, as it is much stronger on the apical portion of the leaf, when compared to the basal one. Another research, from the same group, strongly suggests that on the induction of CAM in young pineapple plants is mediated by abscisic acid (ABA) and nitric oxide (NO). Based on both of these results, this work intends to characterize the role of NO and ABA in CAM signaling, using as a model of study a species which is generally accepted to be a facultative CAM on natural conditions. Besides that, G. Monostachia shows different degrees of CAM along the leaf blade, which makes an interesting model of it for signaling studies. It was also attempted to use detached leaves as a valid model of study for this species. Since no remarkable differences were detected between an experiment performed with whole plants or detached leaves alone, it was chosen to carry over the work using only detached leaves. The induction of CAM was performed by drought, using a 30% polyethyleneglycol (PEG) solution. The nocturnal acid accumulation and the activity of phosphoenolpyruvate carboxylase (PEPC) and malate dehydrogenase (MDH) enzymes were measured in three portions of the leaf (basal, middle and apical). The water amount was indicative of the water loss on foliar tissues. NO participation was assessed through chemioluminescence, spectrofluorimetry and in situ localization by fluorescence microscopy. A NO donor was also used. ABA was quantified by gas chromatography associated with mass spectrometry (GC-MS). The leaves changed the photosynthetic metabolism from C3 to CAM on the sixth day after the beginning of PEG exposure (as stated by the nocturnal acid accumulation and PEPC activity), but the decrease in water amount values started soon, after 12 hours of exposure, and stabilizing after 24 hours. The major loss of water percentage was detected on the basal portion, persisting until the seventh day, while on the apical portion, after two days the control and PEG-treated leaves remained similar. Since the C3-CAM change occurred in the apical portion, it is possible to suggest a signal transport from the base to the apex of the leaf in response to water loss. Indeed, the ABA levels remained higher with the water loss along the whole leaf, but with greater intensity on the apical portion. Higher NO levels were also detected on PEG-treated leaves, but only on the apical portion. The in situ localization of NO corroborates the spectrofluorimetry, showing an increase on the sixth day after PEG exposure on the leaf apex. In conclusion, both NO and ABA seem to participate on the signaling of CAM. Possibly, ABA plays a decisive role on indicating drought, because it increases on the whole leaf subjected to PEG, while NO is, maybe, a secondary signal, specific to processes that occur only on the apical portion, such as the CAM induction.
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Maleckova, Eva [Verfasser], Andreas P. M. [Akademischer Betreuer] Weber, and Matias [Gutachter] Zurbriggen. "Regulation of crassulacean acid metabolism (CAM) in the facultative CAM species Talinum triangulare / Eva Maleckova ; Gutachter: Matias Zurbriggen ; Betreuer: Andreas P. M. Weber." Düsseldorf : Universitäts- und Landesbibliothek der Heinrich-Heine-Universität Düsseldorf, 2020. http://d-nb.info/1220503487/34.
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Nascimento, Davi Roncoletta. "Respostas de CAM às variações ambientais na bromélia Dyckia tuberosa (Vellozo) Beer." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/41/41134/tde-21012013-143339/.
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Plantas com o tipo fotossintético CAM podem suportar condições de baixa disponibilidade de água através de um sistema de concentração de gás carbônico que aumenta a eficiência de uso da água através de uma fixação inicial do CO2 durante a noite, em condições de baixo déficit de pressão de vapor entre a folha e a atmosfera. Esse processo favorece a ocupação de regiões áridas e de sítios onde a água pode se tornar rapidamente indisponível. A ocorrência desse tipo fotossintético abrange uma grande amplitude de táxons, incluindo a família Bromeliaceae. Entre as espécies de Bromeliaceae que apresentam CAM encontra-se Dickya tuberosa, uma espécie que apresenta uma grande abundancia nos afloramentos rochosos associados ao monumento natural da Pedra Grande - Atibaia - SP. Nesse local, D. tuberose apresenta um papel relevante na vegetação associada à superfície de rocha exposta como componente essencial das comunidades denominadas \"ilhas de vegetação\". As condições predominantes no afloramento rochoso da Pedra Grande são de grande escassez de solo e água, além de extrema exposição. As variações na disponibilidade de água no afloramento rochoso seriam devidas, entre outras causas, ao tamanho das ilhas de solo onde D. tuberose ocorre e as características de declividade e orientação da vertente da superfície rochosa onde a ilha esta instalada. A partir das observações no ambiente natural, pergunta-se se os padrões de assimilação em D. tuberose relacionados ao CAM apresenta variações associadas as características das ilhas de solo onde ocorre. Para investigar esta relação, plantas de D. tuberose foram estudadas em campo e em condições semi-controladas em casa de vegetação. A técnica utilizada para caracterização dos padrões de CAM foi a de titulação da acidez do mesofilo. Tanto em grupos experimentais submetidos a períodos distintos de suspensão da rega como em amostras obtidas diretamente do campo, observam-se padrões de variação da acidez que podem ser associados a variações no suprimento hídrico. As variações foram caracterizadas através da diferença na acidez entre o inicio da manha e o final da tarde. A redução na amplitude da variação coincidiu com a intensidade da restrição no suprimento hídrico. Entretanto, a variação foi associada a redução do valor da acidez no final do dia, o que estaria associado a uma redução na recaptura do CO2 durante o período de iluminação. A maior influencia detectada nas plantas em campo foi a umidade relativa do ar. Conjectura-se um papel da assimilação de água através das folhas de D. tuberose como um atributo essencial a ocupação do substrato rochoso na Pedra Grande - AtibaiaPlants with crassulacean acid metabolism are able to support conditions of low availability of water through a carbon dioxide concentration system which increases the efficiency of use of water through an overnight CO2 fixture under low deficit of vapor pressure between the leaf and the atmosphere. This process favors the occupation of arid regions and places where water can quickly become unavailable. The occurrence of this type photosynthetic covers a wide range of taxa, including the Bromeliaceae family. Among the species of Bromeliaceae presenting CAM is Dickya tuberose, a species that has a great abundance on rocky outcrops associated with natural monument of Pedra Grande - Atibaia - SP. At this site, D. tuberose has a role in vegetation associated with surface rock exposed as an essential component of communities called \"vegetation islands\". The conditions prevailing in the rocky outcrop of Pedra Grande are of great scarcity of land and water, and extreme exposure. The variations in water availability in rocky outcrop would be due, among other reasons, the size of the islands where vegetation D. tuberose occurs and the characteristics of inclination and orientation of the slope of the rocky surface where the island is installed. From the observations in the natural environment, wonders whether the patterns of assimilation in D. tuberose related to CAM presents variations associated characteristics of vegetation islands where it occurs. To investigate this relationship, plants of D. tuberose were studied in field and semi-controlled conditions in a greenhouse. The technique used to characterize patterns of CAM was the titration acidity of the mesophyll. In both experimental groups undergoing different periods of suspension of irrigation as in samples obtained directly from the field, there are patterns of variation in acidity that may be associated with variations in water supply. The changes were characterized by the difference in acidity between the early morning and late afternoon. The reduction in amplitude of the variation coincided with the intensity of the restriction in water supply. However, the variation was associated with reduced acidity value at the end of the day, which would be associated with a reduction in the recapture of CO2 during the illumination period. The major influence detected on plants in the field was the relative humidity. It is conjectured a part of the assimilation of water through the leaves of D. tuberose as an essential attribute of the occupation of substrate in Pedra Grande - Atibaia
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Fondom, Nicolas Yebit. "PHYSIOLOGICAL AND BIOCHEMICAL ADAPTATIONS IN SOME CAM SPECIES UNDER NATURAL CONDITIONS: THE IMPORTANCE OF LEAF ANATOMY." Oxford, Ohio : Miami University, 2009. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=miami1260552594.
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Pereira, Paula Natália. "Divisão espacial da atividade das enzimas PEPC e da NR e sua regulação por citocininas em folhas de Guzmania monostachia induzidas ao CAM." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/41/41132/tde-19122012-215637/.
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Estudos anteriores realizados no Laboratório de Fisiologia Vegetal do IBUSP com Guzmania monostachia demonstraram que quando essas plantas são submetidas ao déficit hídrico ocorre a indução do CAM, com maior expressão desse metabolismo na porção foliar apical. Para outra espécie (Vriesea gigantea), foi verificada a maior atividade da enzima nitrato redutase (NR) na porção basal durante o período diurno. Em uma bromélia terrestre (Ananas comosus) foi observada a sinalização por citocininas tanto na indução da expressão gênica, quanto na ativação da NR. Outros laboratórios evidenciaram que plantas de Mesembryanthemum crystallinum induzidas ao CAM apresentaram uma provável regulação negativa da fosfoenolpiruvato carboxilase (PEPC) por citocininas. Em decorrência desses conhecimentos acumulados, surgiram novos questionamentos: haveria variações diuturnas da atividade das enzimas PEPC e NR nas diferentes porções das folhas de G. monostachia induzidas ao CAM? A maior disponibilidade de esqueletos carbônicos à noite (acúmulo de acidez) influenciaria positivamente a atividade da NR, deslocando seu pico de atividade para o período noturno? As variações dos teores endógenos de citocininas acompanhariam as possíveis mudanças da atividade da PEPC e da NR, indicando, assim, a participação dessa classe hormonal na regulação dessas enzimas? O presente trabalho teve por objetivo principal investigar uma possível regulação da atividade das enzimas PEPC e NR por citocininas em folhas destacadas da bromélia epífita com tanque, Guzmania monostachia (Bromeliaceae) induzidas ao CAM. Foi esperado com esta pesquisa aprofundar os estudos sobre a inter-relação entre o comportamento fotossintético, a capacidade de assimilação de nitrogênio e a possível regulação das atividades da PEPC e da NR por citocininas endógenas. Análises de acidez titulável, ácidos orgânicos, amido endógeno e da atividade da enzima malato desidrogenase (MDH) foram realizadas, confirmando a indução do CAM nas folhas isoladas de G. monostachia mantidas em polietilenoglicol (PEG) a uma concentração de 30%. O uso desse composto foi eficiente na redução do conteúdo relativo de água e na imposição da deficiência hídrica foliar. Além disso, pôde-se verificar a maior expressão do CAM na porção apical das folhas mantidas em PEG 30%, quando comparada à porção basal. Análises da atividade da PEPC e da NR permitiram verificar a separação espacial dessas enzimas. A primeira apresentou maior atividade no ápice foliar, enquanto a segunda mostrou a maior atividade na porção basal. Apesar disso, não foi observada a separação temporal dessas enzimas, uma vez que ambas apresentaram picos de atividade noturna. A maior atividade da NR durante o período escuro (01 hora) foi verificada nas folhas-controle ou sob deficiência hídrica. Esse resultado sugere que outros fatores, diferentes do metabolismo CAM, influenciaram para a ocorrência da maior atividade dessa enzima durante o período noturno. Os resultados obtidos ainda sugerem que as citocininas possivelmente atuaram como um regulador negativo para a atividade da PEPC durante o dia, uma vez que os maiores níveis endógenos desse hormônio foram observados durante esse período, enquanto a maior atividade dessa enzima foi verificada durante a noite, quando os teores de Z+iP decaíram significativamente. A aplicação de Z ou iP resultou também num decréscimo da atividade dessa enzima. Por outro lado, as citocininas atuaram como um provável regulador positivo para a atividade da NR, uma vez que a maior atividade noturna dessa enzima foi antecedida em 3 ou 6 horas pelos maiores níveis endógenos de citocininas na porção basal das folhas mantidas em água ou PEG 30%, respectivamente. A aplicação de citocininas-livres aumentou significativamente a atividade da NR na base das folhas destacadas mantidas em água ou PEG 30%Prior studies undertaken in the Laboratory of Plant Physiology on IBUSP with Guzmania monostachia have shown that during water shortage, CAM induction occurs with greater expression in the apical portion of the leaf. In the case of another species (Vriesea gigantean), more intense nitrate reductase (NR) enzyme activity was observed in the basal portion during the daytime. In a certain terrestrial bromeliad (Ananas comosus), signaling by cytokinins, both in the induction of gene expression as well as NR activation, was observed. According to other laboratories, the cytokinins seem to play a negative regulation of phosphoenolpyruvate carboxylase (PEPC) in CAM induced Mesembryanthemum crystallinum plants. As a result of accumulated knowledge, new questions have arisen, such as: Are there daily variations in PEPC and NR enzymes activity in the different portions of CAM induced leaves of G. monostachia? Would the more pronounced nocturnal availability of carbon skeletons (accumulation of acidity) positively influence NR activity, with consequential displacement of its peak of activity to this period? Would variations in endogenous cytokinins concentration accompany possible changes in PEPC and NR activity, thereby indicating the participation of this hormonal class in their regulation? The main aim in the present study was to investigate the possible regulation of PEPC and NR activity by cytokinins in detached CAM-induced leaves of the epiphyte tank bromeliad Guzmania monostachia (Bromeliaceae). The expectations with this research were to study more deeply the inter-relationship between photosynthetic behavior, the capacity for nitrogen assimilation and the possible regulation of PEPC and NR activity by endogenous cytokinins. Analyses of titratable acidity, organic acids, endogenous starch and malate dehydrogenase (MDH) enzyme activity confirmed CAM induction in isolated leaves of G. monostachia kept in polyethylene glycol (PEG) at a concentration of 30%. The use of this compound was efficient in reducing relative water content and imposing leaf water deficiency. Furthermore, compared to the basal portion, greater CAM expression could be observed in the apical portion of leaves kept in PEG 30%. Analyses of PEPC and NR activity allowed detecting their mutual spatial separation, seeing that, in the first greater activity was concentrated in the leaf apex, while in the second this was more pronounced in the basal portion. Even so, no temporal separation could be observed, since peak of activity for both occurred at night. The peak of nocturnal NR activity (1 hour) was observed in control leaves or those undergoing water deficiency, thereby implying that factors, other than CAM metabolism, exerted an influence on the occurrence of more intense activity of this enzyme at this time. Furthermore, there were indications that cytokinins possibly act as a negative regulator of PEPC activity during the daytime, when the highest endogenous levels of this hormone were observed, whereas it was apparent that the most intense activity of this enzyme actually occurred at night, when Z+iP rates decreased significantly. Z or iP application also induced a decrease in the activity of this enzyme. On the other hand, the cytokinins acted as a positive regulator of NR activity, since the nocturnal peak of activity of this enzyme was preceded by 3 or 6 hours by higher endogenous levels of cytokinins in the basal portion of leaves maintained in water or PEG 30%, respectively. The application of free cytokinins induced a significant increase in NR activity in the base of detached leaves kept in water or PEG 30%
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Bispo, Simone Mesquita. "Variação na composição isotópica do carbono e nitrogênio da matéria orgânica e biomassa da coroa foliar de Aechmea aquilega (Salisb.) griseb bromeliaceae em caatinga, agreste e mata atlântica de Sergipe." Universidade Federal de Sergipe, 2011. https://ri.ufs.br/handle/riufs/4447.
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The bromeliads are conspicuous elements of the landscape and vegetation of Brazil, in the state of Sergipe occurs in the Atlantic forest ecosystems in the ecotone and caatinga. Bromeliads have an semiarid environment in adaptive capacity to occupy various habitats both on the ground, rocks and trees is partly attributed to its CAM photosynthetic response type obligatory and/or facultative. Isotopic studies to determine the leaf carbon isotope values show that these range from -10 to -28 of PDB standard. This study analyzed the isotopic composition of carbon and nitrogen organic matter and leaf in the crown of Aechmea aquilega at three habitats: Caatinga (white forest sclerophilous), Atlantic forest (Pirambu) and a transition area between Atlantic Forest and Caatinga, an exception area of white sand-quartizose. In each habitat were collected 4 bromeliads that live in isolated bush and four plants in the ground substrates with the objective of evaluating the hypothesis of facilitation of bromeliad-tank as accumulator of organic matter. The leaves and organic matter of the crown leaves were dried in a ventilated oven, crushed, sieved and made isotopic analysis of carbon-13, nitrogen-15, and total C:N on CENA-USP laboratories. The results of analysis of content C: N and isotope ratios showed significant variations of carbon and nitrogen in the crown of leaves, as well as the total abundance in both leaf biomass and particulate organic matter. Plants of Caatinga and Atlantic Forest obligatory assimilate carbon, while the ecotone of the bromeliads, the National Park of Serra de Itabaiana responded as much as in CAM binding to isolated bushes just as the composition of bromeliads is probably of autoctone origin-open grassy areas. The isotope ratio of the 15N is 22 times more enriched in the bromeliad leaf biomass of scrub plants in relation to the white sands and 2.6 higher than in the Atlantic forest habitat, while the particulate organic matter was enriched in all habitats, but the source this organic matter require explanation, however, the study supported the hypothesis on the functional role of facilitation in the three bromeliad habitats. According to the study, we observed that the adaptive success of higher plants associated with scrub bushes when the same was not observed in other habitats. In white sands bromeliads-tank, the substrate is sandy-quartzes hot, highly permeable, facilitating evaporation and drought in the summer suggesting that there is a condition of great stress, which these tank bromeliads are well adapted to soil and not on trees.Estudos isotópicos para determinar os valores dos isótopos do carbono foliar mostram que estes variam -10 a -28 do padrão PDB. Este estudo analisou a composição isotópica do Carbono e Nitrogênio foliar e a matéria orgânica acumulada na coroa foliar de Aechmea aquilega de três habitats: Caatinga (Poço Verde), Mata Atlântica (Pirambu) e em um área de transição Mata Atlântica Caatinga (Areia Branca). Em cada habitat foi coletado quatro bromélias que vivem em moitas e quatro plantas isoladas em substratos do chão com o objetivo de avaliar a hipótese de facilitação da bromélia-tanque como acumuladora de matéria orgânica. As folhas e a matéria orgânica da coroa foliar foram secas em estufa ventilada, trituradas, peneiradas e as análises isotópicas do carbono, nitrogênio, teor de carbono e nitrogênio total foram realizadas no CENA-USP. Os resultados das analises de teor C:N e razões isotópicas mostraram variações significativas do carbono e nitrogênio na coroa foliar, assim como na abundância total tanto na biomassa foliar como na matéria orgânica particulada. As plantas da Caatinga e Mata Atlântica assimilam carbono facultativamente, enquanto as bromélias do ecótono, Parque Nacional da Serra de Itabaiana responderam como CAM obrigatórias tanto quando em moitas como isoladas, assim como estas bromélias tem composição de origem autóctone provavelmente de áreas abertas-graminosa. A razão isotópica do N15 é 22 vezes mais enriquecido na biomassa foliar das bromélias da Caatinga em relação às plantas das Areias Branca e 2,6 maiores que em habitat de Mata Atlântica, enquanto a matéria orgânica particulada em todos habitats foi enriquecida, porém a origem desta matéria orgânica necessita de explicações, todavia, o estudo apoiou a hipótese de facilitação no papel funcional da bromélia nos três habitats. De acordo com o estudo, foi observado que o sucesso adaptativo maior das plantas da Caatinga quando associada a moitas o mesmo não foi verificado nos outros habitats. Nas Areias Brancas, o substrato arenoso-quartizoso é quente, altamente permeável, favorecendo a evaporação e déficit hídrico no verão o que sugere que haja uma condição de grande estresse, a qual essas bromélias-tanque estão bem adaptadas no solo e não nas árvores.
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Davies, J. A. "Functional genomics of nocturnal carboxylation in Crassulacean acid metabolism." Thesis, University of Liverpool, 2017. http://livrepository.liverpool.ac.uk/3021607/.
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Jones, Alexander M. "Fuel Yield Potential of Field Grown Agave americana L. Based on Water Soluble Carbohydrates, Acid Extractable Carbohydrates, and Enzymatic Digestibility Compared to Other Advanced Biofuel Feedstocks." Ohio University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1501173804378294.
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Goodsall, Christopher William. "The role of pyrophosphate dependent phosphofructokinase in Crassulacean acid metabolism plants." Thesis, University of Cambridge, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361686.
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Paul, Matthew J. "Studies of crassulacean acid metabolism in Mesembryanthemum crystallinum and Kalanchoe daigremontiana." Thesis, University of Leicester, 1988. http://hdl.handle.net/2381/35336.
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Studies of crassulacean acid metabolism in Mesembryanthemum crystallinum and Kalanchoe daigremontiana Matthew J. Paul Studies of crassulacean acid metabolism (CAM), were undertaken in Kalanchoe daigremontiana and in the inducible CAM plant Mesembryanthemum crystallinum. Irrigation of M. crystallinum plants with 400 mM NaCl initiated CAM activity; CAM was deinduced by saturating the cultivation soil with water. Diel fluctuations and amounts of malic acid in M. crystallinum correlated with levels of endogenous inorganic phosphate (Pi). However, growth of M. crystallinum plants at varying concentrations of exogenous Pi resulted in an inverse relationship between these components. Indeed, diel fluctuations of malic acid in C3 M. crystallinum grown at 0 Pi were CAM-like. Cellular compartmentation of Pi and multi-functional roles of Pi and malic acid may explain these phenomena. The response of carbohydrate levels in M. crystallinum to photon fluence rate revealed that in conditions of restricted assimilate supply the CAM form partitioned carbohydrate preferentially as starch. Investigations of the control of this partitioning implicated differences in the properties of cytosolic fructose 1, 6 bisphosphatase between C3 and CAM M. crystallinum. Growth of M. crystallinum at varying exogenous Pi concentrations demonstrated less perturbation of starch accumulation at high Pi in the CAM form. The involvement of fructose 1, 6 bisphosphatase and Pi in carbohydrate partitioning is discussed. Dry matter data, carbohydrate levels and saturation of carbohydrate accumulation and malic acid decarboxylation at 250 umol m-2 s-1 in CAM M. crystallinum indicated low productivity. Preferential partitioning of carbohydrate into starch, the adoption of CAM and growth in a saline environment may contribute to this. CAM induction in M. crystallinum was accompanied by the accumulation of pinitol. Preparations of protoplasts, vacuoles and chloroplasts showed pinitol to be chloroplastic at a probable concentration of about 230 mM and cytosolic at about 100 mM. No pinitol was detected in vacuoles. Pinitol, a putative compatible solute, may contribute to osmotic adjustment particularly in chloroplasts in response to the cellular accumulation of NaC1. There was no indication of a causal link between pinitol and CAM.
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Huber, John Anthony. "Exploring the Possibility of Photosynthetic Plasticity in Agave sensu lato." BYU ScholarsArchive, 2016. https://scholarsarchive.byu.edu/etd/6403.
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Crassulacean acid metabolism (CAM) provides desert plants with distinct advantages over the C3 and C4 photosynthetic pathways in harsh climates where water is scarce. CAM is, however more metabolically costly than C3 or C4 photosynthesis, and some plants, such as Mesembryanthemum crystallinum, facultatively utilize CAM when water is abundant, and water conservation unnecessary. In such situations, these plants behave akin to a C3 plant when photosynthesizing. CAM is divided into four phases, with each phase displaying unique metabolic processes. Certain changes, including changes in the timing of CO2 fixation, stable carbon isotope ratios, and tissue malic acid content accumulation patterns can indicate that a plant has shifted from CAM to C3 photosynthesis. Such shifts have been observed to be regulated primarily by water availability and ontogenic development. While facultative CAM is well documented in species like Mesembryanthemum crystallinum, and it has not been studied extensively in Agave with the exception of Agave deserti, and Agave angustifolia. A better understanding of this phenomenon would apply to the agricultural growth of this genus. This study aimed to trigger C3 to CAM shifts in Agave sensu lato species, in order to expand upon the findings of previous studies, and better understand the prevalence of facultative CAM expression in the genus. Gas exchange and stable carbon isotope measurements were taken from 2-month-old, 10-month-old, and mature agaves grown in controlled ocnditions. Tissue acid content measurements were taken from mature plants. Despite the Agave sensu lato species in this study being subjected to moisture applications ranging from dry to saturated, we were unable to observe any distinct shifts from CAM to C3 photosynthesis in any of the species tested for both seedlings and mature plants. Diel net CO2 fixation rates also increased with age, and water applications for seedlings, and decreased with heavy irrigation in mature plants. Stable carbon isotope ratios revealed that some carbon in the plant tissues was fixed by rubisco, and that some species (Polianthes tuberosa, Prochnyanthes mexicana) had carbon isotope ratios of a C3 plant, but these ratios did not change with different irrigation treatments. Malic acid accumulation remained typical of CAM plants for the species tested as well, with one exception in Polianthes tuberosa. As such, we conclude that the Agave sensu stricto species tested in this study are obligate CAM plants, and that they perform poorly mature individuals are over-watered. Additionally, the Agave sensu lato species P. mexicana, and P. tuberosa appear to be C3 plants given the results of this study.
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Warren, Mark Anthony. "Tonoplast proton-translocating ATPase from the crassulacean acid metabolism plant Kalanchoe daigremontiana." Thesis, University of Edinburgh, 1993. http://hdl.handle.net/1842/27028.
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Roberts, Andrew. "Crassulacean acid metabolism and photosynthetic plasticity in the genus Clusia : an ecophysiological study." Thesis, University of Newcastle Upon Tyne, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.360879.
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Haider, Muhammad Sajjad. "Impact of crassulacean acid metabolism on carbon balance and growth of Mesembryanthemum crystallinum." Thesis, University of Newcastle Upon Tyne, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.427390.
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Haslam, Richard Philip. "Adaptations of the bromeliad Tillandsia usneoides to the epiphytic niche." Thesis, University of Newcastle Upon Tyne, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.285690.
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Bupphada, Phaitun. "Functional genomics of Crassulacean acid metabolism in the monocot biomass feedstock crop Agave sisalana." Thesis, University of Liverpool, 2015. http://livrepository.liverpool.ac.uk/2053199/.
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Certain Crassulacean acid metabolism (CAM) crops have been recognised as having great potential for the production of renewable biomass for bioenergy production from seasonally dry lands. The work described in this thesis sought to investigate the functional genomics of CAM development and light/ dark regulation in the obligate CAM species Agave sisalana. Semi-quantitative RT-PCR analysis was employed to study the regulation of CAM genes in leaf tissues. The transcript levels of the CAM genes phosphoenolpyruvate carboxylase (AsPPC) and pyruvate orthophosphate dikinase (AsPPDK) were highest in the mature tip, lower in the young, expanding base, and very low to undetectable in the most basal white tissue of the youngest fully expanded leaf from ~3-month-old plants. The PEPC kinase gene (AsPPCK) did not show a clear pattern of differential regulation of its transcript level between the leaf tip and base. CO2 exchange measurements, immuno-blotting of known CAM proteins and malate measurements further confirmed CAM induction in the leaf tip. Furthermore, this is the first report of a circadian rhythm of CO2 fixation in a monocot CAM species. The phosphorylated form of PEPC was only detected in the leaf tip in the dark. Sucrose was highest in the leaf tip, and showed strong light/ dark regulation and clear evidence for circadian clock control. A putative sucrose metabolism-related gene, cell wall invertase (As_cwINV), exhibited strong light/ dark regulation and a robust circadian rhythm in the leaf tip. De novo transcriptome assembly using Illumina RNA-sequencing data totalling ~90 Gbp was generated from light and dark samples of the white basal, pale green basal, and dark green tip sections of the youngest fully expanded leaf sampled in the light (2 h before dusk) and dark (2 h before dawn). Differential expression analysis identified novel CAM-induced transcription factor genes AsNAC (c566713_g1), AsWRKY (c571790_g2), and AsPLATZ (c541787_g1), which exhibited a robust pattern of both light/ dark regulation and circadian clock control, which was established using Q-RT-PCR analysis. Overall, this study provides a high quality whole transcriptome assembly and quantitative analysis resource underpinning future functional genomics studies of CAM in A. sisalana. The CAM-induced and circadian clock controlled transcription factors identified in this study could also be investigated further through generating stable transgenic RNA interference lines or other approaches to determine their functions. This study has also proposed a novel CAM pathway showing leaf development and light/ dark regulation of CAM genes, including the fructan metabolism pathway, thereby providing a better understanding of how fructan might be synthesised and accumulated and turned over to supply part of the PEP required for nocturnal CO2 fixation, in addition to the utilisation of sucrose by CAM in the A. sisalana leaf.
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Bohn, Andreas. "Analysis and Simulation of Circadian Multi-Oscillator Systems in a Crassulacean Acid Metabolism Plant." Phd thesis, [S.l. : s.n.], 2003. http://tuprints.ulb.tu-darmstadt.de/367/1/abohn_dr_1.pdf.
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Crassulacean acid metabolism (CAM) is an adaptation of photosynthetic organisms to drought stress: improved water-use efficiency is achieved by an optimized temporal arrangement of photosynthetic subprocesses, which are driven by an endogenous pacemaker, i.e. a circadian clock. The present work deals with the hypothesis that the circadian rhythm of gas-exchange of entire leaves of the CAM plant Kalanchoë daigremontiana has to be understood as the collective signal of the population of cells in the leaf. In this multi-oscillator picture, certain features of the whole-leaf rhythm can be understood as a desynchronization of the population due to noise and synchronization due to common environmental stimuli, respectively. This hypothesis is checked by comparison of numerical simulations of uncoupled populations of two different phenomenological models of circadian rhythms to experimental data obtained from monitoring the spatio-temporal metabolic dynamics in the leaf by means of chlorophyll-fluorescence imaging. The comparison shows that the features of the whole-leaf rhythm are also exhibited by each individual cell, hence the predicted emergence of new effects at the population level cannot be confirmed. Further spatio-temporal analyses and simulations suggest that pattern formation and the appearance of synchronized clusters in the leaf are induced by spatially heterogeneous fluctuations of environmental parameters. A further focus of interest is on the analysis of multi-variate time-series of whole-leaf gas exchange. Comparison of numerical simulations based on a physiological model of CAM to experimental data suggests that circadian rhythm generation cannot be understood by considering a single pacemaker situated at the metabolic level. Rather, evidence is presented that the observable rhythms are the output of a functional network of multiple original oscillators, situated at multiple levels from gene expression to stomatal guard cells. Future work, both experimental and numerical, is proposed to address questions of pattern formation by spatial heterogeneity, as well as unraveling the network structure of circadian rhythm generation in CAM.
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Slocombe, Stephen Peter. "Changes in enzyme profile during the induction of crassulacean acid metabolism in Mesembryanthemum crystallinum." Thesis, University of Leicester, 1991. http://hdl.handle.net/2381/35351.
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Niechayev, Nicholas Alexander. "The Environmental Productivity and Photosynthetic Light Response of Agave americana:A Potential Semi-Arid Biofuel Feedstock." Ohio University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1468518584.
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Wood, Daniel. "Genetic and environmental enablers of the evolution of Crassulacean Acid Metabolism in submerged aquatic plants." Thesis, University of Sheffield, 2018. http://etheses.whiterose.ac.uk/20350/.
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Elliott, Stewart M. "Signals and constraints for the induction of crassulacean acid metabolism in the model halophyte Mesembryanthemum crystallinum." Thesis, University of Newcastle Upon Tyne, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.437558.
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Barrera, Zambrano Victoria Andrea. "Implications of leaf anatomy and stomatal responses in the Clusia genus for the evolution of Crassulacean acid metabolism." Thesis, University of Newcastle Upon Tyne, 2012. http://hdl.handle.net/10443/1534.
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The tropical genus Clusia which contains species with C3, Crassulacean acid metabolism and C3/CAM properties is an interesting model to dissect anatomical, physiological and molecular traits that underpin the evolution of CAM photosynthesis. About 7 % of higher plants perform CAM, a specialised photosynthetic pathway, characterized by CO2 uptake during the night mediated via the enzyme phosphoenolpyruvate carboxylase (PEPC) and keeping stomata shut for much of the day. CAM confers high water use efficiency (WUE) and has long been considered an adaptation to drought stress and high irradiance. In some species like Clusia CAM facilitates remarkable photosynthetic plasticity in dealing with changing environments. Thus, CAM plants are important and challenging model organisms for investigating plant responses to global climate change and for examining the anatomical and physiological traits that underpin enhanced water use efficiency. In this thesis strong relationships were found between the magnitude of CAM photosynthesis in eight species of Clusia (C. hilariana, C. alata, C. rosea, C. lanceolata, C. aripoensis, C. grandiflora, C. tocuchensis and C. multiflora) and six leaf anatomical traits (stomatal size, stomatal density, % intercellular air space, length of mesophyll exposed to air space, cell size and specific leaf area) . These relationships point to leaf anatomical features as important in the evolution of CAM, and also have implications for the behaviour of stomata and their response to light. It was found that CAM species of Clusia have lower densities of larger stomata compared with C3 species of Clusia. The CAM species of Clusia still maintain a high WUE and it was hypothesised that this was a consequence of robust circadian control of stomatal conductance which was maintained under different light regimes. To examine the response of CAM stomata to contrasting light regimes and to test if circadian oscillations in stomatal conductance are disrupted under different wavelengths of light, gas exchange measurements were recorded during 48 hours under constant light regimes (either white light, blue light, red light or darkness) for C. rosea a constitutive CAM plant, and C. multiflora, a constitutive C3 plant. It was found that the species responded differently to variation in light regimes and the response of stomata to blue light in the CAM Clusia had not been lost, as proposed by previous workers. The larger stomata of C. rosea responded faster to changes in light intensity during the photoperiod compared with those of C. multiflora, but this did not happen during the night. It was hypothesised that the kinetic responses of the CAM stomata might be important for optimising carbon gain and reducing water loss under changing environmental conditions at the start and end of the day. Furthermore, circadian control of stomatal conductance was found to be mediated by both photoreceptors and metabolism, including photosynthesis and carbohydrate metabolism in CAM and C3 Clusia plants. A molecular approach was taken to probe the mechanisms underpinning the contrasting responses to light. The differential transcript abundance, of photoreceptors involved in stomatal opening (phototropin 1 and phototropin 2) and circadian regulation (cryptochrome 2 and phytochrome A) was examined for C. rosea and C. multiflora under different constant light regimes using semi-quantitative reverse transcription- PCR and Real Time PCR. Diel expression patterns of phototropins were found to differ between the C3 and CAM species in terms of transcript abundance, the level of control exerted by circadian clock over the transcripts and the response of transcripts to different light regimes. It was concluded that stomatal responses to light in Clusia species must be mediated by a coordinated labour of different photoreceptors to exert control over water loss and CO2 assimilation. Further work is required to assess the expression and regulation of photoreceptors at the stomatal guard cell level. Having more knowledge regarding the function of stomata in CAM plants and their implications for WUE should help inform efforts for improving the water use of crop species in the light of environmental challenges such as desertification and global warming.
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Waller, J. L. "Characterisation of transcription factors with potential roles in the circadian optimisation of Crassulacean acid metabolism in Kalanchoë fedtschenkoi." Thesis, University of Liverpool, 2015. http://livrepository.liverpool.ac.uk/3000503/.
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Crassulacean acid metabolism (CAM) is a metabolic adaptation of photosynthesis that is optimised via strict temporal regulation of its biochemistry by the circadian oscillator. CAM plants achieve high water use efficiency and thus thrive in seasonally dry regions unsuitable for C3 food crops such as rice or wheat. Climate change and the associated challenges of global food and energy security, mean that CAM research is currently of urgent and pressing need, as CAM may reveal methods for the generation of more water use efficient crops. The efficiency of CAM is optimised by the circadian clock, through the regulation of PHOSPHOENOLPYRUVATE CARBOXYLASE KINASE (PPCK) expression and nocturnal CO2 fixation, but the signalling pathway between the central clock and CAM has yet to be elucidated. Whole genome sequencing and detailed RNA-seq datasets for C3 and CAM leaves of the model CAM species Kalanchoë fedtschenkoi have enabled the discovery of novel genes that could function to link CAM to the circadian clock. Three CAM-induced and clock-controlled transcription factor (TF) genes were identified from the RNA-seq datasets: MYB-LIKE 439 (KfMYB439), CAM-INDUCED BZIP1 (KfCIB1) and CYCLING DOF FACTOR2 (KfCDF2). Both over-expressor and RNAi knockdown transgenic lines of K. fedtschenkoi were generated for each TF, facilitating the further elucidation of their biological functions. Over 200 transgenic lines were screened for altered expression levels, and changes to the dawn and dusk levels of key CAM metabolites: malate and starch. Four transgenic lines for each TF, two over-expressor and two RNAi lines, were used for detailed phenotypic analysis of CAM-associated traits. Transgenic perturbation of any one of the three TFs caused small but widespread changes to the transcript levels of core clock- and CAM-associated genes. KfMYB439 is a REVEILLE family TF related to the clock gene CIRCADIAN CLOCK ASSOCIATED1 (CCA1). Data revealed that KfMYB439 functioned close to the core circadian oscillator. Mis-regulation of KfMYB439 led to the perturbation of efficient dark CO2 fixation, reduced levels of starch and malate, and reduced productivity during drought. KfCIB1, was found to feed back to influence the core circadian clock as well as regulating CAM. In constant light conditions, KfCIB1 mis-expression led to perturbed timing of KfCCA1 and TIMING OF CAB1 (KfTOC1) . KfCIB1 mis-regulation also impacted on stomatal control. At dusk and dawn, large and rapid changes in stomatal conductance resulted in spikes of CO2. Mis-expression also resulted in small improvements in productivity in water-limited environments. KfCDF2 was found to function not only in the clock control of CAM, but also in the photoperiodic control of flowering time. In terms of CAM and the clock, KfCDF2 mis-expression caused changes to CCA1, TOC1 and PPCK expression, and arrhythmic CO2 fixation in constant conditions. It also impacted on water retention during drought, with both over-expressor and RNAi lines displaying higher succulence than the wild type lines after 90 days of drought. KfCDF2 over-expression in both K. fedtschenkoi and K. laxiflora caused constitutive flowering in long days, whereas wild type plants never flowered. Q-RT-PCR analysis of flowering pathway genes revealed that KfCDF2 over-expression impacted on transcript levels for CONSTANS (CO) and FLOWERING LOCUS T (FT); key proteins in the day-length dependent induction of flowering. Results suggested that all three TFs likely function in the circadian optimisation of CAM, although whether or not the often small effects were direct or indirect will require further work. Future Chromatin Immunoprecipitation and sequencing experiments will reveal the target genes regulated by these TFs, and the identification of other novel CAM-induced genes from the RNA-seq data, will allow the pathway between the circadian clock and CAM to be elucidated in much greater detail.
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Meszter, Zsolt Roland. "Molecular characterisation of transcription factors with potential roles in the circadian regulation of Crassulacean acid metabolism in Kalanchoe fedtschenkoi." Thesis, University of Liverpool, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.539485.
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Costa, Fernanda Reinert Thome. "On the Bromeliaceae of the restinga of Barra de Marica in Brazil : environmental influences on the expression of crassulacean acid metabolism." Thesis, University of Newcastle Upon Tyne, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.261237.
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Freschi, Luciano. "Sinalização hormonal e do óxido nítrico na indução do metabolismo ácido crassuláceo em Ananas comosus." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/41/41132/tde-28012009-162750/.
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A expressão do metabolismo ácido crassuláceo (CAM) nas plantas C3-CAM facultativas pode ser fortemente modulada por uma variedade de sinais ambientais e endógenos. Visto que plantas de abacaxizeiro (Ananas comosus, variedade Smooth Cayenne) podem apresentar comportamento fotossintético do tipo C3 ou CAM quando cultivadas in vitro, o presente trabalho buscou analisar a participação de quatro classes hormonais (ácido abscísico, citocininas, auxinas e etileno), do cálcio citossólico (Ca2+cit.) e do óxido nítrico (NO) na regulação da expressão do CAM nessa bromélia. Para tanto, os teores endógenos desses sinalizadores foram quantificados durante a indução e a reversão do CAM em abacaxizeiro. Além disso, também foram realizadas análises do grau de expressão do CAM em plantas tratadas com esses compostos sinalizadores ou com seus inibidores de síntese, transporte ou percepção. Os dados obtidos evidenciaram uma correlação positiva entre os teores endógenos de ácido abscísico (ABA) e a expressão do CAM em abacaxizeiro, uma vez que a indução e a reversão do CAM foram acompanhadas de, respectivamente, aumentos e reduções no conteúdo foliar desse hormônio. Em consonância com esses resultados, o fornecimento de ABA exógeno resultou na indução do CAM em plantas mantidas na ausência de estresse hídrico, indicando, portanto, um efeito estimulatório desse hormônio sobre a expressão do CAM em A. comosus.Entretanto, constatou-se que a inibição do acúmulo de ABA não afetou a indução do CAM em resposta ao estresse hídrico, sugerindo que a transição de C3 para CAM em abacaxizeiro pode ocorrer tanto por uma via de sinalização dependente de ABA quanto por uma via independente de ABA. De modo inverso, os dados indicaram que as citocininas atuariam como reguladoras negativas da expressão do CAM em abacaxizeiro, uma vez que a aplicação desse hormônio inibiu parcialmente a indução do CAM em resposta ao estresse hídrico e, além disso, o conteúdo endógeno das quatro citocininas analisadas foi inversamente proporcional ao grau de expressão do CAM nessa bromélia. As auxinas e o etileno, por sua vez, parecem não estar envolvidos na regulação dos processos de indução e de reversão do CAM em abacaxizeiro. Por outro lado, os dados obtidos indicaram, de forma inédita, um papel sinalizador positivo do NO sobre a expressão da fotossíntese CAM. Verificou-se, por exemplo, que a aplicação de NO exógeno promoveu um aumento considerável na expressão do CAM em plantas de abacaxizeiro e, de modo condizente, foi observado um incremento na produção desse radical livre durante a transição da fotossíntese C3 para CAM em resposta ao estresse hídrico. Além disso, foi interessante constatar que a elevação na síntese de NO nos tecidos foliares de abacaxizeiro ocorreu principalmente no parênquima clorofiliano, sendo este tecido um dos principais alvos das alterações metabólicas necessárias para o estabelecimento da fotossíntese CAM. Os resultados também sugerem que o NO atuaria como um mensageiro secundário do sinal do ABA na indução do CAM, já que a produção desse radical livre aumentou consideravelmente nas plantas tratadas com ABA e, em paralelo, tratamentos com seqüestrador de NO bloquearam parcialmente a indução do CAM em resposta ao ABA. Por fim, os tratamentos com quelante ou ionóforo de cálcio evidenciaram que o aumento na concentração citoplasmática desse íon desempenha uma função crucial na regulação da indução de A. comosus ao CAM em resposta ao estresse hídrico. De acordo com os resultados, alterações na concentração Ca2+ citossólico parecem representar um ponto de convergência entre as vias de sinalização dependente e independente de ABA que levam à indução do CAM em abacaxizeiro. Em conjunto, os dados obtidos no presente trabalho indicam que o ABA, o NO e o Ca2+ citossólico interagem durante os eventos que sinalização que resultam na transição de C3 para CAM em abacaxizeiro, enquanto que as citocininas parecem reprimir a expressão da fotossíntese CAM.The Crassulacean acid metabolism (CAM) expression in C3-CAM facultative plants can be strongly modulated by a diversity of environmental and endogenous signals. Since pineapple (Ananas comosus, variety Smooth Cayenne) plants can perform either C3 or CAM photosynthesis when grown in vitro, this work attempted to investigate the involvement of four hormonal classes (abscisic acid, cytokinins, auxins and ethylene), cytosolic calcium (Ca2+cit.) and nitric oxide (NO) on the regulation of CAM expression in this bromeliad. To achieve this, the levels of these signaling compounds were measured during the pineapple C3-to-CAM induction and the CAM-to-C3 reversion. Furthermore, the degree of CAM expression in plants treated with these compounds and their inhibitors of synthesis, transport or perception was also analyzed. The data obtained showed that the endogenous levels of ABA were positively correlated with the degree of CAM expression in pineapple, since the C3-to-CAM transition and the CAM-to-C3 reversion in this bromeliad were preceded by, respectively, increases and decreases in the ABA leaf content. Consistent with these results; exogenously applied ABA increased the CAM expression in plants maintained in the absence of water stress, thus, indicating a stimulatory effect of this hormone on the A. comosus CAM expression. However, the inhibition of ABA accumulation did not affect the CAM induction by water stress, suggesting that the pineapple C3-to-CAM transition can occur via both ABA-dependent and ABA-independent signaling pathways. On the opposite, the data indicated that cytokinins act as negative regulators of CAM expression in pineapple, since the adding of this hormone partially inhibited the CAM induction by water stress and, additionally, the endogenous levels of the four cytokinins analyzed were inversely proportional to the degree of CAM expression in this bromeliad. Auxins and ethylene, conversely, seem not to be involved in the regulation of the C3-to-CAM transition and the CAM-to-C3 reversion in pineapple. On the other hand, the data obtained indicated, by the first time, a positive signaling role for the NO on the expression of CAM photosynthesis. For instance, it was observed that the exogenously applied NO increased the CAM expression in pineapple plants and, in agreement; there was an elevation in the production of this free radical during the water stress-induced C3-to-CAM transition. Additionally, the elevation of the NO synthesis in the pineapple leaf tissues occurred mainly in the chlorenchyma, which is the plant tissue responsible for most of the metabolic changes necessary to the CAM photosynthesis establishment. The results also suggested that the NO may act as a second messenger of the ABA signal in the pineapple CAM induction, since the production of this free radical in ABA-treated plants increased considerably and, in parallel, treatments with a NO scavenger partially blocked the ABA-induced C3-to-CAM transition. Finally, treatments with calcium chelator or ionophore indicated that the increase in the cytosolic concentration of this ion plays a crucial role in the regulation of the CAM induction by water stress in A. comosus.According to the results, changes in the concentration of Ca2+ cytosolic seem to represent a convergence point between the ABA-dependent and ABA-independent signaling cascade leading to CAM induction in pineapple. Taken together, the data obtained in the present work indicated that ABA, NO and cytosolic Ca2+ interact during the signaling events leading to the pineapple C3-CAM transition, while the cytokinins seem to repress the expression of CAM photosynthesis.
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Cai, Pu Ren, and 蔡溥仁. "Calcium ions/calmodulin dependent stomatal behavior in Kalanchoe daigermontiana, a crassulacean acid metabolism (CAM) plant." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/29zx75.
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LIAO, CHENG-KANG, and 廖成康. "The enhancement of crassulacean acid metabolism in mesembryanthemumcrystallinum L. by abscisic acid." Thesis, 1992. http://ndltd.ncl.edu.tw/handle/07162246856796227406.
Full textAbstract:
博士國立臺灣大學
農藝研究所
80
Mesembryanthemum crystallinum L. 植物在高濃度鹽分處理下或水分逆境下， 光 合作用由 C3 型代謝轉移為 CAM （ Crassulacean acid metabolism ）型代謝， 搮類物種稱為可誘致的 CAM 植物（ inducible or facultative CAM plant ）。 由於生理及生化上昏特質，CAM植物可於夜間固定CO2，減少水分散失，適應缺水環 境， 因此利用此誘發性的 CAM 特質，可探討高等植物如何透過生理反應的調節及 基因的表理，以適應不良的環境。 逆境下植物荃爾蒙有明顯變化，其中離層酸（ abscisic acid，ABA ）扮演重要角 色。 逆境下大量累積的離層酸可能與植物的適應性有關， 因此推測可誘致的 CAM 植物在鹽害或缺水環境下，亦可能有離層酸的累積，其與光合作用的調節，尤其與 PEPCase基因表現，是目前研究的方向之一。 本試驗以 M. crystallinum 植物為材料， 分別澆灌 400mM NaCl、 100 μ M ABA 及 15 ％ PEG-6000 於土壤。 利用間接式酵素免疫法（ indirect enzyme-linked immunosorbent assay， ELISA ）分析內生荷爾蒙離層酸變化與 PEPcarboxylase 活性之關係，並分析氣孔導度、蘋果酸及可滴定酸的含量日夜週期消長情形，以確 定 CAM 代謝進行。最後利用 fluridone 抑制離層酸的合成，探討環境因子、離層 酸與 CAM代謝之關係。 本試驗結果顯示，利用間接式酵素免疫分析，檢測（＋） -cis-ABA 皂濃度範圍可 達 0.05 至 5.00 pmol/well， 由平行測試的結果瞭解， 葉片組織經 PVP 管柱、 C18 短管柱及高效能液相層析儀純化步驟，即可進行間接式酵素免疫分析。四週齡 植株葉片皂內生離層酸濃度很低，外加鹽處理無法促進內生離層酸濃度及 PEPCase 活性增加，推測幼齡基離層酸昏合成受阻，可能影響 PEPCase 基因的活化。 五週 齡植株雖然內生離層酸濃度低，但可因鹽、PEG 及外加離層酸處理，促進葉片離層 酸濃度於 24 小時快孰增脅，fluridone 處理以抑學內生離層酸合成，再加鹽處理 並不能促進 PEPCase 活性增加。 此外對照組部分的植株，則隨離層酸累積的高峰 ，並且隨株齡增加，氣孔導度、蘋果酸理促進 PEPCase 活性及 CAM 代謝提早表現 ，內生離層酸濃度昏增加是一重要因素，推測離層酸可能是調節 Ppcl 基因起動區 域的活化因子。 #9205652 #9205652
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Ping, Chia-Yun, and 平嘉雲. "Crassulacean Acid Metabolism in Phalaenopsis aphrodite subsp. formosana during Different Developmental Stages." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/47978895966316779612.
Full textAbstract:
碩士臺灣大學
園藝學研究所
98
Mature Phalaenopsis is a typical CAM plant, which is characterized by opening stomata during the night and fixing CO2 by PEPC and thus showing a diurnal fluctuation of titratable acids. However, no remarkable day/night titratable acidity rhythm was detected during the protocorm stages, which suggested that the protocorm stages of Phalaenopsis may not undergo the CAM photosynthesis pathway but C3 pathway. Therefore, the objective of this study is to prove the existence of a photosynthetic transition from C3 to CAM coping with the ontogenetic development in the CAM orchids. Phalaenopsis aphrodite subsp. formosana were prepared according to the seven developmental stages we defined, and the CO2 uptake, malate accumulation, PEPC activity, PEPC and PEPC kinase were investigated. Stages before generation of the primary leaf from protocorm, no net CO2 uptake during the night but the day, and no significant daily change in malate accumulation and PEPC activity indicated that the stages was without CAM characters and behaved nearly-C3. As the protocorm developed the first leaf, the day/night malate change and PEPC activity were first observed; however, the gas exchange remained like the C3 pattern. The CAM characters were getting much more typical along with the leaf maturation, and the seedling ready to transfer out from the flask had turned into an obligate CAM plant just as the mature plant. The expression of PPC, encoded for PEPC, revealed a constitutional pattern in all organs at all developmental stages indicated that the PEPC did not play an important role in the CAM ontogenetic development. Moreover, the expression patterns of PaPPCK, encoded for PPCK (PEPC kinase) were in agreement with the physiological characters just mentioned above. Therefore, we conclude that the photosynthesis shift from C3 to CAM during the ontogenetic development in Phalaenopsis and PaPPCK played a key role in transition. CAM-cycling occurred in the critical stage, protocorm with the primary leaf, which spaced the protocorm and mature plant.
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Wu, Chau-Hui, and 吳昭慧. "The Regulation of Crassulacean Acid Metabolism in Mesembryanthemum crystallinum L. by Ethylene." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/24558475848074426722.
Full textAbstract:
碩士國立臺灣大學
農藝學系
82
1. M. crystallinum plants were maintained in a growth chamber under a 16-h light / 8-h dark cycle and a PPFD of 180 μmol m-2 s-1. Endogenous ACC level was decreased and PEPDCase activity was enhanced in 5-week-old plants treated with 400 mM sodium chloride . Upon spraying ethephon, the sodium chloride-stressed plants exhibited a significant decrease in PEPCase activity and minimal diurnal fluctuation in total titratable acidity and malate content in the leaves. 2. Under the same growing conditions, the ice plants treated with ABA did not show any significant change in PEPCase activity in the leaves. Nocturnal accumulation of total titratable acidity and malate was higher in expression was inhibited by the spray of ethephon. 3. When the 4-week-old plants grown under low PPFD (180 μmol m-2 s-1) were transferred to high PPFD (600 μmol m-2 s-1) for 1 week, the PEPCase activity and ABA content were 6 times higher than those of the plants grown continuously under low PPFD. The treatments of both sodium chloride and ABA exhibited the effect of increasing PEPCase activity in the leaves of ice plants under high PPFD condition. 4. The ice plants responded to sodium chloride similarly with an increase in ABA level under both high and low PPFD irradiation although a much higher level of ABA content was observed under the former condition. ABA accumulation, but not PEPCase activity, was inhibited in the sodium chloride treated plants when ethephon was applied. 5. The results from electrophoretic and western immunoblotting studies indicated that under low PPFD, the amount of PEPC polypeptide was increased and the amount of Rubisco polypeptide was decreased during the developmental course of the plants or under sodium chloride stress. However, the spray of ethephon tended to increase the amount of Rubisco polypeptide and decrease the amount of PEPC polypeptide.
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Barrett, Melissa S. "Carbon acquisition in variable environments: aquatic plants of the River Murray, Australia." 2008. http://hdl.handle.net/2440/47987.
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This thesis considers the implications of changes in the supply of resources for photosynthesis, with regard for modes of carbon acquisition employed by aquatic plants of the River Murray. Carbon supplies are inherently more variable for aquatic plants than for those in terrestrial environments, and variations are intensified for plants in semi-arid regions, where water may be limiting. In changeable environments the most successful species are likely to be those with flexible carbon-uptake mechanisms, able to accommodate variations in the supply of resources. Studies were made of plants associated with wetland habitats of the Murray, including Crassula helmsii, Potamogeton tricarinatus, P. crispus and Vallisneria americana. The aim was to elucidate the mechanisms of carbon uptake and assimilation employed, and to determine how flexibility in carbon uptake and/or assimilation physiology affect survival and distribution. Stable carbon isotopes were used to explore the dynamics of carbon uptake and assimilation, and fluorescence was used to identify pathways and photosynthetic capacity. The studies suggest that physiological flexibility is adaptive survival in changeable environments, but probably does not enhance the spread or dominance of these species. V. americana is a known bicarbonate-user, and it is shown here that it uses the Crassulacean Acid Metabolism (CAM) photosynthetic pathway under specific conditions (high light intensity near the leaf tips) concurrently with HCO[subscript]3 - uptake, while leaves deeper in the water continue to use the C[subscript]3 pathway, with CO₂ as the main carbon source. However, V. americana does not use CAM when under stress, such as exposure to high light and temperature. The diversity of carbon uptake and assimilation mechanisms in this species may explain its competitive ability in habitats associated with the Murray. In this way it is able to maximise use of light throughout the water column. In shallow, warm water, where leaves are parallel to the surface, CAM ability is likely to be induced along the length of the leaf, allowing maximal use of carbon and light. The amphibious C. helmsii is shown to use CAM on submergence, even where water levels fluctuate within 24 hours. This allows continued photosynthesis in habitats where level fluctuations prevent access to atmospheric CO₂. It appears that stable conditions are most favourable for growth and dispersal, and that the spread of C. helmsii is mainly by the aerial form. Carbon uptake by P. tricarinatus under field conditions is compared with that of P. crispus to demonstrate differences in productivity associated with aqueous bicarbonate and atmospheric CO₂ use. P. tricarinatus uses HCO[subscript]3 - uptake to promote growth toward the surface, so that CO₂ can be accessed by floating leaves. Atmospheric contact provides access to light and removes the limitation of aqueous diffusive resistance to CO₂, thereby increasing photosynthetic capacity above that provided by submerged leaves.http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1320380
Thesis (Ph.D) -- University of Adelaide, School of Earth and Environmental Sciences, 2008
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Nelson, Elizabeth Amber. "Functional convergence of crassulacean acid metabolism: A study of functional anatomy in a convergent photosynthetic pathway." 2006. http://link.library.utoronto.ca/eir/EIRdetail.cfm?Resources__ID=450437&T=F.
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Bohn, Andreas [Verfasser]. "Analysis and simulation of circadian multi-oscillator systems in a crassulacean acid metabolism plant = Analyse und Simulation circadianer Multioszillatoren-Systeme in einer Crassulaceen-Säurestoffwechsel-Pflanze / von Andreas Bohn." 2003. http://d-nb.info/968776981/34.
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