Dissertations / Theses on the topic 'Plant hormones'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Plant hormones.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
Baynham, Mark Kevin. "Gibberellin plant growth hormones." Thesis, University of Sussex, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.328329.
Full textPharmawati, Made, and mikewood@deakin edu au. "A study of the natriuretic peptide hormone system in plants." Deakin University. School of Biological and Chemical Sciences, 1999. http://tux.lib.deakin.edu.au./adt-VDU/public/adt-VDU20060727.145040.
Full textBastian, René. "Characterisation of AtPNP-A - a novel arabidopsis thaliana gene with role in water and salt homeostasis." Thesis, University of the Western Cape, 2009. http://hdl.handle.net/11394/2818.
Full textPlant natriuretic peptides (PNPs) are a novel class of extracellular, systemically mobile molecules that elicit a number of plant responses important in homeostasis and growth. Natriuretic peptides were first identified in vertebrates where they play a role in the regulation of salt and water balance. Subsequent experimental investigations have identified the presence of a natriuretic peptide hormone system in plants. While PNPs have been implicated in various physiological responses such as stomatal guard cell movements and regulation of net water uptake, its biological role has remained elusive. Here we have used co-expression and promoter content analysis tools to understand the biological role of the Arabidopsis thaliana PNP (AtPNP-A). The analysis of AtPNP-A and its co-expressed genes revealed that genes annotated as part of the systemic acquired resistance (SAR) pathway were over-represented, thus suggesting that AtPNP-A may function as a component of plant defense responses and specifically, SAR. The results further show that AtPNP-A shares many characteristics with pathogenesis related (PR) proteins in that its transcription is strongly induced in response to pathogen challenges, thus implying a newly described role for AtPNP-A in pathogen attack. Additional tissue expression analysis also indicated distinct localization of PNP activity in sepals and transcriptional meta-analysis showed that AtPNP-A may play a role in starch breakdown. Therefore, together with the finding that AtPNP-A plays a role in regulating phloem transport, we also hypothesize that AtPNP-A may play a role in phloem unloading in sepals to assist processes such as seed formation in plants. In plants, the second messenger, guanosine 3’,5’-cyclic monophosphate (cGMP) mediates a whole range of important processes including salinity tolerance, disease resistance, drought tolerance and responses to light. Since PNPs regulate water and salt homeostasis via a cGMP-dependent signaling pathways, it is thus important to analyse the transcriptome induced by the second messenger (cGMP) in Arabidopsis thaliana to give a better understanding of its mechanism of action. This study was also supplemented by the analysis of the gibberellic acid (GA) dependent transcriptome, since cGMP also plays a role its transcription pathway. This data analysis, together with promoter content investigation, revealed that genes upregulated after cGMP treatment and down-regulated in the GA insensitive mutant (ga1-3) were enriched with a GA response element (GARE), while no GARE enrichment were observed in genes up-regulated in the ga1-3 mutant. These findings suggest that GARE is indicative of GA-induced and cGMP-dependent transcriptional up-regulation. Gene ontology analysis confirmed previous reports that cGMP is involved in ion homeostasis and indicated that the transcriptional cGMP response is bi-polar in the sense that both genes up- and down-regulated in response to cGMP is involved in cation transport. Additionally, ab initio analysis of genes transcriptionally dependent on cGMP identified CHX8 as a hub gene and promoter content of CHX8 co-expressed genes show enrichment of the GARE motif. The fact that CHX8 has its highest expression levels during male gametogenesis and pollen tube growth, together with our findings, suggest that GA-induced and cGMP- dependent genes may play a key role in ion and water homeostasis in the male gametophyte. Finally, we propose that the type of analysis undertaken here can yield new insights into gene regulation networks and inform experimental strategies to unravel complex transcription regulatory systems under different developmental and stimulus specific conditions.
South Africa
Woods, S. L. "Analysis of plant hormones involved in potato dormancy." Thesis, University of Bristol, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384566.
Full textLeung, Ching-man. "Characterization of two auxin-induced ACC synthase genes in tomatoes." Click to view the E-thesis via HKUTO, 2005. http://sunzi.lib.hku.hk/hkuto/record/B36748845.
Full textVeerappan, Vijaykumar. "Molecular and genetic analysis of the function of cis-cinnamic acid in arabidopsis thaliana /." View abstract or full-text, 2004. http://library.ust.hk/cgi/db/thesis.pl?BIOL%202004%20VEERAP.
Full textIncludes bibliographical references (leaves 78-85). Also available in electronic version. Access restricted to campus users.
McCoy, Mark Christopher. "The effects of phytohormones on growth and artemisinin production in hairy root cultures of artemisia annua l." Link to electronic thesis, 2003. http://www.wpi.edu/Pubs/ETD/Available/etd-0529103-162012/.
Full textHerrington, Edward John. "Light quality effects on in vitro shoot proliferation of Spiraea nipponica." Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/28809.
Full textLand and Food Systems, Faculty of
Graduate
Wai, King-ming. "Purification and characterization of beta-cyanoalanine synthase from rice (Oryza sativa)." Hong Kong : University of Hong Kong, 2001. http://sunzi.lib.hku.hk/hkuto/record.jsp?B23234581.
Full textHove, Runyararo Memory. "Evolutionary development and functional role of plant natriuretic peptide (PNP)-B." Thesis, University of Fort Hare, 2009. http://hdl.handle.net/10353/155.
Full textHays, Dirk B. "The role of plant hormones in Brassica napus embryo development." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq20742.pdf.
Full textWilliams, James Timothy. "Total Synthesis of Bacterial Carbohydrates and Plant-derived Glycopeptide Hormones." Thesis, The University of Sydney, 2016. http://hdl.handle.net/2123/15508.
Full textYuan, Kun Wysocka-Diller Joanna Singh Narendra K. "Functional and genetic analysis of plant transcription factors involved in the plant growth under various environmental conditions." Auburn, Ala, 2008. http://repo.lib.auburn.edu/2007%20Fall%20Dissertations/Yuan_Kun_37.pdf.
Full textAthmani, Salah. "Synthesis of cytokinin analogues." Thesis, University of Salford, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.304608.
Full textRogers, Jennifer Jacqueline Mavis. "Mutational analysis of the maize auxin binding protein, ABP1." Thesis, University of the West of England, Bristol, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.249341.
Full textWard, Jane Louise. "Probing the mechanism of gibberellin 20-oxidase and a structure-activity study of methyl jasmonate and related derivatives." Thesis, University of Bristol, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361109.
Full textHarrison, Polly A. "Partial synthesis of selected gibberellins." Thesis, University of Bristol, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.294577.
Full textOakeley, Edward James. "Promoter analysis of auxin-binding protein genes from Zea mays L. and Fragaria x ananassa." Thesis, University of Bristol, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260811.
Full textTaylor, Catherine. "A mechanism of action of strigolactone." Thesis, University of Cambridge, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.709140.
Full textGarnaat, Carl William 1957. "PHYTOHORMONAL REGULATION OF 3-HYDROXY-3-METHYLGLUTARYL COENZYME A REDUCTASE IN PLANT CELL CULTURES (ABSCISIC ACID, MEVINOLIN)." Thesis, The University of Arizona, 1986. http://hdl.handle.net/10150/276793.
Full textZhang, Tao. "Regulation of EGY1 gene expression by environmental factors and developmental cues /." View abstract or full-text, 2005. http://library.ust.hk/cgi/db/thesis.pl?AMCE%202005%20ZHANG.
Full textBalasubramanian, Rajagopal. "Harlequin (hlq) : an arabidopsis mutant that ectopically expresses Dc3-GUS and shows defects in cell wall morphogenesis /." View Abstract or Full-Text, 2003. http://library.ust.hk/cgi/db/thesis.pl?BIOL%202003%20BALASU.
Full textIncludes bibliographical references (leaves 197-236). Also available in electronic version. Access restricted to campus users.
Xing, Ti. "Hormone binding in plants." Thesis, De Montfort University, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.280511.
Full text偉景明 and King-ming Wai. "Purification and characterization of beta-cyanoalanine synthase from rice (Oryza sativa)." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2001. http://hub.hku.hk/bib/B31225275.
Full textFeys, Bart Julienne Frans. "Towards positional cloning of COI1, an arabidopsis gene controlling the response to coronatine and methyl jasmonate." Thesis, University of East Anglia, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317974.
Full textWeir, A. J. "#alpha#-ketogutarate dependent gibberellin hydroxylases and plant growth regultion." Thesis, University of Bristol, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233760.
Full textVerveridis, Philippos. "Characterisation and partial purification of the enzyme responsible for ethylene synthesis from 1-aminocyclopropane-1carboxylic acid in plant tissues." Thesis, University of Reading, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303175.
Full textHoffman, Sister Angela. "Hormonal regulation of cell development and polyphenol biosynthesis in cultured Populus trichocarpa cells /." Full text open access at:, 1989. http://content.ohsu.edu/u?/etd,220.
Full textKatsir, Leron J. "Biochemical characterization of the COI1-JAZ receptor for jasmonate." Diss., Connect to online resource - MSU authorized users, 2008.
Find full textKaliff, Maria. "Genes, hormones and signalling pathways implicated in plant defence to Leptosphaeria maculans /." Uppsala : Dept. of Plant Biology and Forest Genetics, Swedish University of Agricultural Sciences, 2007. http://epsilon.slu.se/2007119.pdf.
Full textRuzvidzo, Oziniel. "Plant Natriuretic Peptides - Elucidation of the Mechanisms of Action." Thesis, University of the Western Cape, 2009. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_5854_1285860491.
Full textSeveral lines of cellular and physiological evidence have suggested the presence of a novel class of systemically mobile plant molecules that are recognized by antibodies generated against vertebrate atrial natriuretic peptides (ANPs). Functional characterization of these immunoanalogues, referred to as immunoreactive plant natriuretic peptides (irPNPs) or plant natriuretic peptides (PNPs), has shown that they play important roles in a number of cellular processes crucial for plant growth and maintenance of cellular homeostasis. Although the various biological roles of PNPs in plants are known, their exact mode of action remains elusive. To elucidate the mechanisms of action for these immunoanalogues, we have prepared a biologically active recombinant PNP from Arabidopsis thaliana (AtPNP-A) and the biological activity was demonstrated by showing its ability to induce water uptake into Arabidopsis thaliana protoplasts. In addition, the molecule was shown to downregulate photosynthesis while at the same time up-regulating respiration, transpiration as well as net water uptake and retention capacities in the sage Plectranthus ecklonii. Further analysis of the recombinant AtPNP-A indicated that the peptide can induce systemic response signalling though the phloem. A recombinant Arabidopsis wall associated kinase-like protein (AtWAKL10) that has a domain organization resembling that of vertebrate natriuretic peptide (NP) receptors was also partially characterized as a possible receptor for the recombinant AtPNP-A. Vertebrate NP receptors contain an extracellular ligand-binding domain and an intracellular guanylate cyclase (GC)/kinase domain and signal through the activity of their GC domain that is capable of generating intracellular cGMP from GTP. The structural resemblance of AtWAKL10 to vertebrate NP receptors could suggest a functional homology with receptor molecules and it is conceivable that such a receptor may recognize PNPs as ligands. The characterization of the recombinant AtWAKL10 showed that the molecule functions as both a GC and a kinase in vitro. This strengthened the suggestion that AtWAKL10 could be a possible AtPNP-A receptor especially considering the fact that AtPNP-A applications to plant cells also
trigger cGMP transients. Furthermore, a bioinformatic analysis of the functions of AtPNP-A and AtWAKL10 has inferred both molecules in plant pathogen responses and defense mechanisms, thus indirectly functionally linking the two proteins.
Simancas, San Martín Bárbara. "Importancia de la vitamina E y los jasmonatos en la respuesta de las plantas ante la distinta disponibilidad de fósforo." Doctoral thesis, Universitat de Barcelona, 2017. http://hdl.handle.net/10803/462069.
Full textPhosphorus is a macroelement essential for the development and growth of all plants. Phosphorus deficiency causes many symptoms in plants, activating their stress response mechanisms. The response of stress in plants is usually based on the level of antioxidants produced and the synthesis of endogenous hormones. We studied the role of vitamin E, an important antioxidant in plants, and the production of jasmonates, a stress response hormone, in response to phosphorus availability. Vitamin E played an important role in controlling longevity, depending on the phosphorus availability. α-Tocopherol increased longevity and prevented senescence in plants under control conditions, excess phosphorus or mild phosphorus starvation. However, α-tocopherol accelerated senescence under severe phosphorus deficiency. Furthermore, vitamin E deficiency increased jasmonates levels, suggesting a trade-off between activating the mechanism of photoprotection and the activation of biotic or chemical defences in plant. A reduced growth and photoprotection in vitamin E mutant´s favours the capacity to synthesize chemical defences, such as jasmonates under abiotic stress conditions, thus suggesting again, a trade-off between growth, photoprotection and chemical defences. Conversely, vitamin E plays a major role in the regulation of fatty acid metabolism and could help transfer signals from chloroplast to the nucleus, suggesting vitamin E influences retrograde signalling. In addition, there are effects of priming on the transcript levels of 45 genes encoding, transcriptions factors mainly associated with growth and stress in wild-types plants in response to low phosphorus availability. Therefore, it appears α-tocopherol not only protects plants from photo-oxidative stress under phosphorus availability, but also controls defence-related transcriptional reprogramming and hormonal modulation. On the other hand, an increased nutrient availability in the soil can alleviate photoinhibition and photo-oxidative stress in the leaves of drought stressed nettle plants, especially in females. Sexratio increased under reduced phosphorus availability, increasing the number of females over males, probably because females are the most vulnerable gender under stress conditions. Females enhanced 12-oxo-phytodienoic acid contents under reduced phosphorus availability. This increase was, however, not accompanied by increases in other jasmonates, thus suggesting specific defensive roles for 12-oxo-phytodienoic acid in females.
Subramanian, Senthil. "Short blue root (sbr), an arabidopsis mutant that ectopically over-expresses and ABA- and auxin-inducible transgene Dc3-GUS and has defects in the cell wall /." View Abstract or Full-Text, 2002. http://library.ust.hk/cgi/db/thesis.pl?BIOL%202002%20SUBRAM.
Full textIncludes bibliographical references (leaves 238-266). Also available in electronic version. Access restricted to campus users.
Cherif, Hayett. "EFFECT OF IBA AND DMSO ON IMPROVING BENCHGRAFT RESPONSE OF VITIS CHAMPINI 'DOG-RIDGE' ROOTSTOCK." Thesis, The University of Arizona, 1985. http://hdl.handle.net/10150/275367.
Full textBjörklund, Simon. "Plant hormones in wood formation : novel insights into the roles of ethylene and gibberellins /." Umeå : Dept. of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, 2007. http://epsilon.slu.se/200781.pdf.
Full textGuinn, Gene, and Donald L. Brummett. "Irrigation and Nitrogen Effects on Plant Hormones, Boll Retention, and Growth of Fruiting Branches." College of Agriculture, University of Arizona (Tucson, AZ), 1987. http://hdl.handle.net/10150/204460.
Full textCampos, Marcelo Lattarulo. "Controle hormonal da defesa à herbivoria em tomateiro." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/11/11144/tde-19052009-081547/.
Full textEven though the cultivation of tomato has a high economical importance, this culture is classified as being of elevated risk because of it common infestation by pests and diseases. This problem makes this culture greatly dependent of the application of several agrochemicals, which leads to increase in cost of production, environmental damages and also facilitating the appearance of new pests and diseases. Looking carefully to the problem, it is possible to conclude that a great part of tomato losses are caused by herbivory-arthropods, which are capable of feeding of several parts of the plant, causing, generally, losses in the productivity. However, tomato has natural defense mechanisms against those pests, for example trichomes and allelochemicals, which act poisoning the arthropods, hindering their movement through the plant and/or altering steps of their development. The search for tomato genotypes with great density of trichomes and elevated levels of allelochemicals is nowadays being considered as a hot spot of research, because of the benefits it would provide (for example: a decrease in the cost of production and also a higher productivity). Although it is believed that many plant hormones are involved in the generation of anti-herbivory traits, a great focus has been given only to jasmonic acid because of it clear action in the formation of those traits, such as trichomes, allelochemicals, proteinase inhibitors and many others. The present work objective was to evaluate which hormones are involved in the formation of anti-herbivory traits such as trichome density and allelochemicals and proteinase inhibitors content. For this reason, we made use of several hormonal mutants already introgressed in the Micro-Tom cultivar (which presents benefits as small size and fast life cycle). It was showed that jasmonic acid is an important hormone in the formation of these traits, but other phytohormones also play important roles. Ethylene, gibberellins and auxin alters trichome density indirectly, by altering the area of epidermal cells and thus cell number. Jasmonic acid is a positive regulator of trichome formation, the allelochemicals zingiberene content and also in the formation of proteinase inhibitors. However, brassinosteroids acts by negatively controlling all of those. Interestingly, we observed that this negative control happens through the control of jasmonic acid pathway, a hormonal interaction that was proved by double-mutant analysis. Results obtained in tests with the polyphagous insect Spodoptera frugiperda and the tomato specific pest Tuta absoluta (tomato pinworm) and also with qPCR showed the importance of jasmonic acid, brassinosteroid and their interaction in herbivory defense. Our data suggest that future studies about the formation of antiherbivory traits should be analyzed by focusing the functions not only of jasmonic acid but also brassinosteroid and their antagonist functions.
Zhang, Xunzhong. "Influence of Plant Growth Regulators on Turfgrass Growth, Antioxidant Status, and Drought Tolerance." Diss., Virginia Tech, 1997. http://hdl.handle.net/10919/30739.
Full textPh. D.
Dorans, Alison M. I. "The role of endogenous signals in defence and resistance responses of tomato." Thesis, University of York, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265659.
Full textLeung, Ching-man, and 梁靜雯. "Characterization of two auxin-induced ACC synthase genes in tomatoes." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B36748845.
Full textSCHEERENS, JOSEPH CARL. "HORMONAL CONTROL OF SEX EXPRESSION IN BUFFALO GOURD (CUCURBITA FOETIDISSIMA HBK.)." Diss., The University of Arizona, 1985. http://hdl.handle.net/10150/187938.
Full textJunior, Celso Gaspar Litholdo. "Identificação e expressão de genes da biossíntese do jasmonato na interação entre Theobroma cacao e Moniliophthora perniciosa." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/64/64133/tde-10122009-100915/.
Full textWitches broom disease of cacao (Theobroma cacao L.), caused by the basidiomycete Moniliophthora perniciosa is an important disease and the use of resistant varieties is the only economic and environmental long-term solution. Plant hormones are essential in the signaling network involved in the response against a variety of biotic and abiotic stresses. It is well recognized the crucial role of salicylic acid (SA), ethylene (ET) and jasmonate (JA) in plant-pathogen interactions. The mechanism of resistance observed in Theobroma cacao against M. perniciosa does not appear to involve hypersensitivity response mediated by AS signaling, and it is characterized by lower incidence of symptoms and reduction of mycelial growth in resistant material. The response regulated by JA and/or ET is determined by the growth inhibition and a reduction of the colonization of infected tissues by the pathogen, together with an attenuation of symptoms. It is also associated with an induction and production of the protease inhibitors, lytic enzymes and enzymes of secondary metabolism and the genes enconding these enzymes have shown differential expression patterns in samples inoculated with M. perniciosa. It has been recently demonstrated that the production of AS by the fungus M. perniciosa could be associated with a hormonal disorder in the plant, which could therefore help the pathogen in the infective process. Considering this, the hypothesis that JA and/or ET would regulate the interaction of T. cacao with M. perniciosa was formulated in order to be tested by this research work. It is known that the transcription of genes encoding the enzymes of the JA biosynthesis pathway is induced by exogenous application of methyl jasmonate (MJ) and by pathogen, thus, in order to verify the involvement of JA in defense response of cocoa, sequences of genes that encode the enzymes of the JA biosynthesis pathway were isolated, identified, classified and had their identity confirmed by sequencing, and relative quantitative gene expression were evaluated in susceptible \'P7\' and resistant \'CAB 214\' plants of T. cacao. In addition genes Sams, Accox, Pal , Jaz and Della, were evaluated in experiments with application of inducers (AS, ET and MJ) and inoculation with M. perniciosa. Analysis of relative gene expression by RT-qPCR were conducted and \'P7\' seems to have the expression of jasmonate biosynthesis genes in a more intense and more specific manner when treated with MJ, while \'CAB 214\' shows an earlier yet lower response suggesting that the mechanism of positive regulation by the exogenous application of MJ also occurs in T. cacao. For the inoculation, the gene expression results suggest a difference in the transcriptional response from inoculation with M. perniciosa between \'P7\' and \'CAB 214\' in T. cacao. The effect of AS produced by the fungus may not have antagonistic effects in resistant materials such as \'CAB 214\', as indicated by the increase of the transcription of Aos gene that encodes the main enzyme involved in JA biosynthesis, so the defense responses of \'CAB 214\' is possibly triggered by JA signaling, because the central role of AOS in its biosynthesis, and may be part of synergistic ET signaling, indicated by high Samsi expression in resistance material
Wang, You. "Development of yeast-based methods to screen for plant cytokinin-binding proteins." Access electronically, 2004. http://www.library.uow.edu.au/adt-NWU/public/adt-NWU20060123.141512/index.html.
Full textNorberg, Åke. "Isolation and characterization of regulatory peptides and bioactive compounds /." Stockholm : Karolinska institutet, 2004. http://diss.kib.ki.se/2004/91-7349-882-3/.
Full textRobles, Linda Marie. "Characterization of EER4 and SAR1 in relation to their role in ethylene signaling and dampening responses." Diss., [Riverside, Calif.] : University of California, Riverside, 2010. http://proquest.umi.com/pqdweb?index=0&did=2019848141&SrchMode=2&sid=3&Fmt=2&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1274116478&clientId=48051.
Full textIncludes abstract. Available via ProQuest Digital Dissertations. Title from first page of PDF file (viewed May 17, 2010). Includes bibliographical references. Also issued in print.
Bergonci, Tábata. "Análise funcional dos peptídeos RALF em Arabidopsis: avaliação do efeito do hormônio brassinolide em plantas superexpressoras e silenciadas para os genes AtRALF1 e AtRALF34." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/11/11144/tde-29052012-104800/.
Full textLike in animals, plant peptide hormones play important roles in growth, development and defense. RALF is a peptide hormone ubiquitous in plants that was first isolated from tobacco leaves. Although its function has not been established, the information gathered so far suggest its involvement with basic aspects of cellular biology, probably cellular elongation. RALF peptides in Arabidopsis are found in a multigene family of 37 members. Transgenic plants overexpressing AtRALF1 under the control of the strong constitutive promoter 35S, show a semi-dwarf phenotype and root growth inhibition. A similar phenotype was also observed when AtRALF23 was overexpressed. AtRALF23, as opposed to AtRALF1, is inhibited by brassinosteroids. These facts suggest that different RALF peptide hormones, despite the convergence to the same function, show a unique relationship with other hormones. The goal of this work was to contribute to the determination of the function of RALF peptides in plants and to clarify the inter-relationship between RALF and the other plant hormones. With that in mind, the isoforms AtRALF1 and AtRALF34 were selected based on primary structure similarity/dissimilarity and pattern of gene expression. Plants with high levels of expression or silenced for both genes were obtained and evaluated. The gene construct AtRALF1-GFP was introduced in Arabidopsis under the control of the 35S promoter and fluorescence was observed in the endoplasmic reticulum, Golgi apparatus and apoplast. Genes previously reported as induced in 35S:AtRALF1 plants were validated and used in AtRALF1 peptide and brassinolide experiments. Taken together our results suggest an antagonistic effect of the peptide AtRALF1 regarding the elongation effect of brassinolide in hypocotyls and roots. Plants with high levels of AtRALF1 are resistant to exogenously applied brassinolide, and do not show typical responses to the steroid hormone. The antagonism between the two hormones was also suggested by the gene expression analysis of the AtRALF1 and brassinolide inducible genes.
Wheelhouse, Nicholas Mark. "The effect of amino acids on growth hormone action in ovine hepatocytes." Thesis, University of Aberdeen, 1999. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=185765.
Full textSantos, Valdinei Moreira dos. "Agrochemicals on growth and hormonal relations of \'Micro-Tom\' and Arabidopsis roots under water deficit conditions." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/11/11144/tde-06012017-171318/.
Full textAs crescentes preocupações oriundas a partir dos atuais debates sobre mudanças climáticas somadas ao descontrolado crescimento da população mundial têm dado espaço para o uso de insumos agrícolas naturais, objetivando sustentabilidade na agricultura. Diante de tais preocupações, é importante pensar antecipadamente e encontrar maneiras de aumentar a produção e a qualidade de alimentos, em um ambiente de supostas mudanças climáticas. Substâncias naturais, como bioestimulantes à base de alga, estão ganhando relevância como melhoradores da produtividade e tolerância a estresses abióticos com crescentes usos na agricultura. Diante desse cenário, é importante compreender os efeitos e modos de ação dessas substâncias na fisiologia das plantas para permitir o desenvolvimento de produtos consistentes e garantir aos produtores soluções que atendam às suas necessidades. Portanto, este estudo foi realizado com o objetivo de entender o papel de agroquímicos (reguladores vegetais clássicos e biostimulantes à base da alga) sobre o desenvolvimento radicular e relações hormonais do tomateiro \'Micro-Tom\' e Arabidopsis sob condições de estresse hídrico. Foi testada a habilidade de extratos Ascophyllum nodosum (ANE) em estimular respostas hormonais em condições de seca e estresse osmótico. Foram realizados experimentos com duas plantas-modelo: Arabidopsis que é largamente utilizada em estudos científicos de plantas e o tomateiro \'Micro-Tom\', uma planta-modelo mais adequada para estudos aplicados à agricultura sob condições tropicais. Foram utilizados mutantes hormonais e linhas-repórter de tomate cultivadas em condições de seca para o estudo dos efeitos dos reguladores vegetias e extratos de alga no crescimento radicular e respostas hormonais, respectivamente. Além disso, foram testados in vitro os efeitos dessas substâncias no crescimento radicular de plântulas de Arabidopsis em condições de estresse osmótico. O desenvolvimento radicular do tomateiro e Arabidopsis foi negativamente afetado pela ocorrência do déficit hídrico causado por seca e estresse osmótico, respectivamente. Inibidores de giberelinas afetaram apenas o crescimento radicular do mutante com baixo nível endógeno giberelinas (gib-3). Extratos da mesma espécie de alga apresentaram diferentes efeitos no crescimento radicular de plântulas de Arabidopsis e resposta hormonal em raízes de tomateiro. ANE A e B aprensenta efeitos opostos no desenvolvimento de raízes. ANE A promove o crescimento radicular enquanto ANE A inibe. ANEs pouco influenciam as respostas auxínicas, contudo, essas substâncias alteram o balanço entre entre ácido abscísico e etileno sob condições de estresse hídrico por seca. A padronização da composição de extratos de alga somada aos estudos sobre os seus efeitos fisiológicos e moleculares em culturas é crucial para o estabelecimento desses insumos agrícolas como uma das soluções para as necessidades atuais e futuras da produção de alimentos.
Abad, Juan Carlos Guerrero. "Identificação da subtilase responsável pelo processamento do prepopeptídeo AtRALF1 em Arabidopsis thaliana." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/11/11137/tde-09022012-162000/.
Full textSince the 90s, a new family of molecules of protein origin and with hormone characteristics has been studied in plants. This group of new molecules, collectively named peptide hormones, is involved in defense, reproduction, growth and development. RALF, one of these peptides, is ubiquitous in plants and is involved in plant development. In Arabidopsis there are 34 RALF-like genes (AtRALFs). Our group has shown that AtRALF1 is processed from a larger precursor by a subtilase. Arabidopsis has 56 subtilases, our goal is the identification of the specific subtilase that is responsible for the AtRALF1 processing. Prediction of subcelular localization and in silico gene expression analysis, both confirmed by RT-PCR expression analysis and chimeric proteins with green-fluorescent protein, allowed the reduction of the initial 56 candidates to only 7 subtilases. Crosses between knockout mutants or RNAi plants expressing low levels of subtilases with overexpressors of AtRALF1 identified the subtilases AtSBT6.1 (At5g19660) and AtSBT5.3 (At2g04160) as potentialy involved in the prepropeptide AtRALF1 processing.
Vilarrasa, Blasi Josep. "Spatial analysis of brassinosteroid signaling in the stem cell niche of Arabidopsis primary root = Caracterització molecular de la funció de BRI1 en les cèl•lules mare de lʼarrel dʼArabidopsis." Doctoral thesis, Universitat de Barcelona, 2014. http://hdl.handle.net/10803/277540.
Full textAquesta tesi doctoral té com a objectiu principal investigar els efectes de les hormones vegetals esteroides, Brassinosteroids (BRs), durant el desenvolupament de lʼarrel primària dʼArabidopsis thaliana (Arabidopsis). Per tal dʼassolir aquest objectiu hem realitzat una caracterització genètica, fisiològica i anàlisi cel•lular de mutants de BRs. Així mateix, sʼha descobert una nova ruta de senyalització que controla les divisions de les cèl•lules mare mediades per BRs, Els nostres resultats experimentals mostren com els BRs controlen la homeòstasi de les cèl•lules mare de lʼarrel. En concret, els BRs promouen la diferenciació de les cèl•lules mare de la columel•la i la divisió dʼun grup de cèl•lules mitòticament inactives que actuen en el manteniment de les cèl•lules mare, el centre quiescent (QC). Mitjançant un abordatge microgenòmic hem identificat un nou element de la ruta de senyalització dels BRs específic de les cèl•lules mare, BRAVO (Brassinosteroids at Vascular and Organizing Centre). BRAVO és un factor de transcripció R2R3 de la família MYB (MYB56), que actua com a regulador negatiu de les divisions de QC. Els nostres resultats mostren un model de regulació negativa, on BES1 reprimeix directament i interacciona amb BRAVO, creant un interruptor molecular que controla les divisions del QC. El treball realitzat durant aquesta tesis doctoral permet proposar una nova funció dels BRs en el control de les cèl•lules mare. BRAVO dóna plasticitat a les cèl•lules mare per a poder respondre al dany sobre lADN, així com robustesa per evitar-lo. El control de la homeòstasi de les cèl•lules mare en plantes és vital per entendre lʼadaptació dʼaquests organismes sèssils i la longevitat que presenten algunes espècies.