Submitted by Maria Beatriz Vieira (mbeatriz.vieira@gmail.com) on 2017-04-06T15:02:06Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) dissertacao_andre_pereira_oliveira.pdf: 438653 bytes, checksum: 76c5f05d7a7e119f1320fdbb851349c9 (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2017-04-19T20:19:01Z (GMT) No. of bitstreams: 2 dissertacao_andre_pereira_oliveira.pdf: 438653 bytes, checksum: 76c5f05d7a7e119f1320fdbb851349c9 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2017-04-19T20:21:37Z (GMT) No. of bitstreams: 2 dissertacao_andre_pereira_oliveira.pdf: 438653 bytes, checksum: 76c5f05d7a7e119f1320fdbb851349c9 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-04-19T20:21:54Z (GMT). No. of bitstreams: 2 dissertacao_andre_pereira_oliveira.pdf: 438653 bytes, checksum: 76c5f05d7a7e119f1320fdbb851349c9 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2015-08-21 / Sem bolsa / A perspectiva futura do agronegócio de hortaliças no mundo é oportuna, pela participação crescente do mercado internacional e expansão de oportunidade no mercado interno. Dentro deste contexto, têm ocorrido problemas associados à germinação das sementes de cenoura, em decorrência de contaminação por fungos. Por isso, a hipótese do trabalho é a de que sementes de cenoura podem ser influenciadas no processo germinativo por apresentarem contaminação por fungos e se desinfestadas superficialmente com diferentes tratamentos, estas podem promover um melhor desempenho na germinação e vigor das sementes. Considerando o exposto, o presente trabalho teve por objetivo avaliar a desinfestação superficial com álcool e hipoclorito de sódio, via tratamento de sementes, para o controle de Alternaria spp. e o desempenho fisiológico de sementes de cenoura. O trabalho foi desenvolvido no Laboratório Didático de Análise de Sementes Dr. Flávio Rocha FAEM-UFPel, no Laboratório de Patologia de Sementes e em canteiros preenchidos com areia. Os fatores estudados no experimento foram: método do papel filtro; testes de germinação; primeira contagem de germinação; envelhecimento acelerado; teste de frio sem solo; emergência a campo e comprimento de parte aérea e raiz. O delineamento experimental foi inteiramente casualizado, em esquema fatorial AxB (Fator A: hipoclorito e álcool, e Fator B: tempo (hipoclorito – 0 min; 2,5 min; 5,0 min; 7,5 min e 10,0 min) e (álcool – 0 s; 10 s; 20 s; 30 s; 40 s e 50 s), com quatro repetições. Conclui-se que a utilização de álcool 70% e solução de hipoclorito 1% para desinfestação superficial das sementes não alteram a qualidade fisiológica das sementes de cenoura, Além disso, ambas as soluções são eficazes para reduzir a infestação das sementes com Alternaria spp. Para álcool, uma melhor assepsia é obtida após 30 segundos de imersão. Para hipoclorito 1%, 7 minutos de imersão são necessários para uma melhor assepsia. / The future perspective of vegetable agribusiness in the world is timely, the growing participation of international market expansion opportunity in the domestic market. Within this context, there have been problems associated with the germination of carrot seeds as a result of fungal contamination. Therefore, the hypothesis of this study is that carrot seeds can be influenced in the germination process by presenting fungal contamination and surface disinfected with different treatments, they can promote better performance in germination and seed vigor. Considering the above, the present study was to evaluate the surface disinfection with alcohol and sodium hypochlorite, via seed treatment for the control of Alternaria spp. and the physiological performance of carrot seeds. The study was conducted at the Seed Analysis Laboratory Didactic Dr. Flavio Rocha FAEM-UFPel, at the Seed Pathology Laboratory and flower beds filled with sand. The factors studied in the experiment were: method of filter paper; germination; first count; Accelerated aging; cold test without soil; Emergency field and shoot length and root. The experimental design was completely randomized in a factorial arrangement AxB (Factor A: hypochlorite and alcohol, and Factor B: time (hypochlorite - 0 min, 2.5 min, 5.0 min, 7.5 min and 10.0 min) and (alcohol - 0 sec, 10 sec, 20 sec, 30 sec, 40 sec and 50 sec), with four replications. It follows that the use of 70% alcohol and 1% hypochlorite solution for surface disinfection of the seeds does not alter the physiological quality of carrot seeds. Moreover, both solutions are effective to reduce the infestation of seeds with Alternaria spp. For alcohol, a better sterilization is obtained after 30 seconds of immersion. 1% hypochlorite for seven minutes immersion is needed to better asepsis.

La carotte, légume racine le plus consommé au monde, voit sa production fortement impactée par diverses maladies dont la brûlure foliaire. Cette maladie, provoquée par le champignon nécrotrophe Alternaria dauci, est considérée comme la plus préjudiciable des maladies foliaires de la carotte. Développer des variétés présentant un niveau de résistance fort et durable à cette maladie est l'un des objectifs principaux des sélectionneurs, notamment en cumulant différentes résistances partielles dans un même génotype. Afin d'optimiser un tel cumul, il est nécessaire de comprendre les mécanismes associés à ces résistances. Dans la première partie de cette thèse, nous avons étudié l'implication de métabolites de défense produits par la carotte dans la résistance partielle de la plante à A. dauci. Nous avons montré un effet inhibiteur de la 6- méthoxymelléine (6-MM) et du falcarindiol, sur le développement du champignon. Cet effet est plus important avec le falcarindiol. De plus, la teneur en falcarindiol est supérieure chez le génotype résistant (Boléro) en comparaison avec le génotype sensible (Presto) et, suite à l'inoculation de la plante par A. dauci, la 6-MM s'accumule de façon plus importante dans les feuilles du génotype résistant. Ces molécules de défense pourraient ralentir le développement du champignon et participer ainsi à la résistance. Dans une seconde partie, nous nous sommes intéressés à l'effet de métabolites toxiques produits par le champignon sur des cultures cellulaires de carotte. Nos résultats montrent une corrélation entre le comportement des cellules traitées (viabilité cellulaire, embryogenèse somatique et activité enzymatique) et la sensibilité/résistance des génotypes évaluée au niveau de la plante entière. Parmi les génotypes les plus résistants au champignon, le génotype I2 résiste mieux à l'application d'extraits fongiques que le génotype K3. Ainsi, la résistance partielle de la carotte face à A. dauci semble inclure des résistances aux toxines. Dans le dernier chapitre, nous avons recherché un lien entre la résistance partielle et les mécanismes de défense de la plante, en particulier ceux liés à la voie des jasmonates. Nos premiers résultats montrent la surexpression du gène PR4 chez le génotype résistant K3, comparativement aux autres génotypes, y compris I2. Nous avons par ailleurs recherché des sites polymorphes (SNP) dans les séquences de quatre gènes de défense. Deux gènes (PAL, GLP) présentent un polymorphisme de séquence entre génotypes. Dans le cas de GLP, les SNPs mis en évidence permettent de différencier un génotype sensible (H1) du génotype K3. L'ensemble de ces résultats semble indiquer la présence d'une diversité des modalités de la résistance partielle de la carotte face à A. dauci. Ainsi, la résistance aux toxines semble jouer un rôle plus important chez I2 que chez K3. Inversement, la résistance de K3, et non celle de I2, semble impliquer la voie des jasmonates. Audelà de leur application en amélioration, ces travaux jettent une lueur sur les mécanismes de la résistance partielle, mécanismes encore très peu connus, même parmi les interactions modèles.

Objective: To establish stable transgenic non-toxic plants as a platform for plant-based vaccine production as well as potential oral delivery system of vaccine antigens for sexually transmitted infections (STIs). The concept is to immunize the mucosal immune system present in the gut-associated lymphoid tissues (GALT). HIV-1 p24 subtype C protein has been used as the main antigen model, in parallel with an engineered unique chimeric MOMP antigen from Chlamydia trachomatis serovar E. Methods: Chimeric MOMP and p24 vaccine antigens were successfully inserted into the nuclear genomes of Arabidopsis thaliana and Daucus carota via Agrobacterium-mediated gene transfer. The characteristics of the genetic inserts and corresponding mRNAs and recombinant proteins in planta were described using several methods, including northern, Southern, and western blotting, ELISA, and a commercial HIV Ag/Ab combination assay. Immunogenicity of the antigens was studied in mice models. Results: Transgenes of both plant species expressing p24 or chimeric MOMP were successfully generated. Additional HIV-1 vaccine antigen candidates were introduced and the genetic inserts have been confirmed in Arabidopsis thaliana. The Arabidopsis thaliana expressing p24 and chimeric MOMP were demonstrated to be stable over generations and antigenicity analyses showed that plant-derived HIV-1 p24 and chimeric MOMP retained immunological epitopes when they were expressed in planta. Oral administration of transgenic plant material generated a priming effect of the immune competent cells present in the GALT, shown by the presence of antigen-specific-IgG in mice sera after boosting. Mice immunized with plant-derived HIV-1 p24 antigen were also analyzed for antigen-specific faecal IgA as well as cellular immune responses. However, detectable levels of the two latter immune responses were not observed. The Chlamydia trachomatis chimeric MOMP antigen was further evaluated for its potential as a vaccine antigen candidate, with positive results indicating a more rapid clearance of the Chlamydia trachomatis infection post immunization. Conclusion: Stable non-toxic transgenic plants expressing either HIV-1 p24 or a novel  Chlamydia trachomatis chimeric MOMP antigens have successfully been developed. The two plant-produced STI vaccine antigens have in initial mice feeding studies provided important proof-of-concept for the oral vaccination approach. Now, immunization studies to expand, en-hance, and improve knowledge of the immune responses generated by the orally delivered transgenic plants are of high priority. / Kemi/biokemi

Resumo: A cenoura (Daucus carota L.) é uma hortaliça amplamente empregada na alimentação do brasileiro, constituindo uma rica fonte de cálcio e vitamina A, de fácil digestão e baixo teor de calorias. A cultivar Brasília foi desenvolvido para ser cultivada no verão, apresentando resistência ao calor, com produtividade média de 30 t ha-1 e ciclo médio de 85 a 100 dias. O presente trabalho teve por objetivo avaliar os possíveis efeitos do estresse hídrico e salino no crescimento e nas características morfológicas da cultivar Brasília. O experimento foi conduzido em casa de vegetação, no Departamento de Engenharia Rural da Faculdade de Ciências Agronômicas, Botucatu-SP, nos meses de setembro de 2009 e janeiro de 2010. O manejo hídrico foi estabelecido com base no potencial de água no solo e foram determinados três níveis de água (-0,01; -0,04 e -0,06 MPa), fazendo-se a reposição de água evapotranspirada por pesagem dos vasos. Foram utilizadas quatro doses de cloreto de sódio (1,41; 2,50; 4,50 e 6,45 dS m-1). O ensaio constituiu-se de um fatorial 3x4 (três níveis de água x quatro doses de salinidade). Os parâmetros morfológicos observados foram: altura da parte aérea, massas fresca e seca de parte aérea; massas fresca e seca da parte radicular (bulbo), comprimento da parte radicular (bulbo), diâmetro da parte radicular (bulbo) e produtividade. Foram realizadas três avaliações morfológicas durante os 100 dias após plantio e avaliações diárias de sobrevivência. A análise estatística dos dados foi feita pela análise de variância e teste de Tukey com 5% de probabilidade. Os resultados nas condições deste experimento permitiram as seguintes conclusões: Não foram observadas diferenças significativas... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The carrot (Daucus carota L.) is a vegetable widely used in the Brazilian diet, constituting a rich source of calcium and vitamin A, digestible and low in calories. The cultivar Brasilia was designed to be cultivated in summer, showing resistance to heat, with an average yield of 30 t ha-1 and average cycle from 85 to 100 days. This study aimed to evaluate the possible effects of water stress and salinity on growth and morphological characteristics of the Brasilia cultivar. The experiment was conducted in a greenhouse at the Department of Agricultural Engineering, Faculty of Agronomic Sciences, Botucatu-SP, on September 2009 until January 2010. The water management was based on soil water potential determined and three water levels (-0.01, -0.04 and -0.06 MPa), but with the replacement of water transpired by weighing the pots. We used four doses of sodium chloride (1.41, 2.50, 4.50 and 6.45 dS m-1). The test consisted of a 3x4 factorial (three levels of water salinity x four doses). The morphological parameters were: shoot height, fresh and dry shoot, fresh and dry weight of roots (bulb), length of roots (bulb), diameter of the root (bulb) and productivity. They performed three morphological evaluations during the 100 days after planting and daily assessments of survival. The statistical analysis was performed by ANOVA and Tukey test at 5% probability. The results allowed the following conclusions: there are not observed significant differences on plant development subjected to different minmum soil water potentials (Ψs) = -0,01; -0,04 e -0,06 MPa; the treatments that did not received saline doses showed higher development in relation to aereal part height and bulb length on three available periods (60, 80 e 100 days after planting); the applied saline doses (1,41; 2,50; 4,50 e 6,45 dS m-1 NaCl) did not statistically affect plant development in relation to fresh and dry of aereal... (Complete abstract click electronic access below) / Orientador: Antonio Evaldo Klar / Coorientador: Antonio Ismael Inácio Cardoso / Banca: Hélio Grassi Filho / Banca: Elisandro Pires Frigo / Mestre

Orientador: Norberto da Silva / Banca: Antonio Ismael Inácio Cardoso / Banca: Paulo César Tavares de Melo / Resumo: Com o objetivo de estudar a variabilidade genética para florescimento prematuro e outras características em uma população de cenoura 'Brasília' com produção de sementes sem necessidade de vernalização, foram estimados parâmetros genéticos em três ciclos de seleção em semeadura de outono-inverno. Os três ciclos foram avaliados simultaneamente num único experimento, em 2007, na Fazenda Experimental da Faculdade de Ciências Agronômicas, Campus de Botucatu/UNESP, localizada no município de São Manuel/SP a 22º44'50" de latitude Sul e 48º34'00" de longitude Oeste. Os tratamentos foram constituídos por 48 progênies de meios-irmãos do ciclo original de seleção, 48 progênies de meios-irmãos do primeiro ciclo de seleção, 50 progênies de meios-irmãos do segundo ciclo de seleção e oito testemunhas comuns para os três ciclos: 'Nantes', 'HT-2000', 'Shin Kuroda', 'Brasília' de quatro diferentes procedências e 'Londrina'. Utilizou-se o delineamento experimental de blocos ao acaso, com 3 repetições e parcelas de 2m2 constituídas de oito sulcos transversais de semeadura espaçados de 25 cm de distância. A colheita foi feita 100 dias após a semeadura, com exceção das testemunhas 'Nantes' e 'Shin Kuroda', que por serem mais tardias foram colhidas aos 120 dias após a semeadura. Durante a colheita as raízes foram separadas em comerciais, apresentando comprimento de 17 a 25 cm e menos que 5 cm de diâmetro, sem a presença de cenouras deformadas, deterioradas, quebradas, rachadas e com outros defeitos que as tornem impróprias para o consumo, em refugo, isto é, fora dos padrões comerciais, e em raízes que apresentavam florescimento prematuro. A produção comercial, expressa em gramas, foi avaliada ao nível de parcela e obtida através da massa de raízes comerciais, a produção total, expressa em gramas,...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: To study the genetic variability for bolting and other characteristics in 'Brasilia' carrots with production of seeds without vernalization, genetic parameters in three cycles of selection in autumn-winter sowing were estimated. The three cycles were evaluated simultaneously in only one experiment in 2007 in the Experimental Farm of the Agronomy School, Botucatu/UNESP Campus, in São Manuel/SP (22ºS44' and 48ºW34'). The treatments were constituted by 48 lineages of half-sibling from the original cycle of selection, 48 lineages of half-siblings of the first cycle of selection, 50 lineages of half-siblings from the second cycle of selection and eight witnesses for the three cycles: 'Nantes', 'HT-2000', 'Shin Kuroda', 'Brasilia' from four different origins and 'Londrina'. The experimental outline of randomized blocks was used, with 3 replications and 2m2 lots of eight sowing transversal ridges spaced out at 25cm of distance. Harvest was carried out 100 days after sowing, exception for 'Nantes' and 'Shin Kuroda' witnesses, which for being late crops had to be harvested 120 days after sowing. During the harvest the roots were separated in commercials, presenting length of 17 the 25cm and less than 5cm of diameter, without the presence of deformed, spoiled carrots, broken, cracked or any other defects for consumption, in rubbish roots, that is out of commercial standards, and in roots presenting bolting. The commercial production, expressed in grams, was evaluated to the level of lots and obtained by the mass of commercial roots. The total production, expressed in grams, was obtained by the addition of the mass of commercial roots and rubbish, except those with premature floral connecting rods. Also obtained the percentage of rubbish mass, the percentage of plants not bolting and the percentage of orange shoulder in relation to the commercial production...(Complete abstract click electronic access below) / Mestre

Ph.d.-afhandling. Den Kongelige Veterinær- og Landbohøjskole, 2002. / Haves også i trykt udg.

<p dir="ltr">Urban agriculture has grown in popularity in recent decades, due to its ability to provide access to healthy fruits and vegetables in urban zones, as well as its importance in fostering knowledge of agriculture within communities. However, urban agriculture may struggle with unique challenges due to its proximity to urban and industrial activities, such as food safety risks due to toxic heavy metals and metalloids which may be present in urban soils in high concentrations. Heavy metals and metalloids (HM) like arsenic, cadmium, and lead are absorbed by plants from the soil, and may accumulate in the plants’ edible tissues, which are consumed by humans. Carrot (<i>Daucus carota</i> L.), in particular, hyperaccumulates these toxic heavy metals in its edible taproots, leading to food safety risks on urban farms.</p><p dir="ltr">One potential way to help address this challenge is to breed carrot varieties with low uptake of HM. In recent years, researchers have identified lines with high and low uptake in greenhouse trials and single location breeding nurseries. However, to be viable, these lines must consistently vary in HM across sites despite differences in environmental and management factors that can also greatly influence HM bioavailability and uptake. Moreover, screening for differences in HM uptake is time-consuming and expensive, and breeders need new tools to select among segregating breeding populations. By using on-farm participatory research as well as advanced phenotyping technologies, we investigate the viability of breeding carrots for HM uptake and the potential of new tools to advance these efforts in order to mitigate the risks on urban farms.</p><p dir="ltr">In the summers of 2021 and 2022, participatory on-farm trials were conducted to determine the HM risks on Indiana urban farms and to investigate the consistency of differences in HM uptake between carrot breeding lines taken from breeding trials (Chapter 2). Results of these trials indicated that while carrot genotype had an effect, there was still significant variability in carrot uptake of arsenic, cadmium and lead between farm sites and years. Results indicated significant differences between site-years, and carrot HM concentrations that correlated strongly with soil concentrations for that particular element. However, there were some site-years with low soil HM content and other soil factors expected to reduce uptake such as pH and phytoavailable zinc concentrations (such as site-year H), that had high carrot HM content. There were significant differences in carrot cadmium (Cd) and arsenic (As) content between carrot breeding lines. For instance, breeding line 3271 had a high As average concentration but low Cd average concentration, while breeding lines 6220 and 2327 had low As and high Cd concentrations. We identify the possibility of other mediating factors, such as uptake of antagonistic micronutrients, or microbe-assisted HM uptake and amelioration that need further attention.</p><p dir="ltr">In the fall of 2022, a study was conducted to investigate the possibility of using phenotyping technologies such as RGB and hyperspectral imaging to detect Cd stress in carrot and attempt to predict uptake (Chapter 3). RGB (red green blue) is a digital color model in which cameras can capture important visual cues compiled from information about each pixel. Hyperspectral imaging uses cameras to capture wavelengths beyond the visible spectrum, which can detect plant stress indicators like increased anthocyanin content for specific environmental stresses. Results of this trial were useful, with some time points and indices noting differences between carrot lines. For instance, RGB factors hue and fluorescence as well as hyperspectral reflectance plots and vegetative indices swirNDVI and ANTH were the most diagnostic. Breeding lines 6636 and 8503 showed the greatest separation between Cd treated and control carrots in imaging indices. However, further studies will be needed to optimize this approach for breeding programs.</p><p dir="ltr">This research demonstrates that growing carrots on most urban farms in Indiana is safe. The studies also provide further evidence that it will be possible to help lower food safety risks by selecting carrot varieties with low HM uptake, and phenotyping can help to advance these efforts. At the same time, new research to understand how soil factors such as microbiomes influence HM bioavailability and uptake on urban farms are also needed to further reduce potential risks. In the meantime, farmers should continue to test their soil for HM and take appropriate actions to reduce risks such as using raised beds and soil amendments that can bind metals like biochar. Consumers should also continue to wash and peel their carrots before consumption, as well as consume a balanced diet with a diverse set of vegetables and other crops.</p>

[ES] El calcio (Ca2+) es un catión esencial que juega un papel fundamental en todos los organismos vivos. Desde el punto de vista funcional, el Ca2+ actúa como un segundo mensajero que regula distintos procesos celulares. Trabajos anteriores indican que la señalización mediante Ca2+ podría estar implicada en las primeras etapas de la inducción de la embriogénesis in vitro de las plantas, pero el verdadero papel del Ca2+ en este proceso es aún desconocido. Por eso, el principal objetivo de la presente Tesis es el estudio del papel del Ca2+ en la embriogénesis in vitro mediante dos sistemas in vitro: la embriogénesis somática y la embriogénesis de microsporas. Para determinar la importancia de la homeostasis del Ca2+ en la inducción de la embriogénesis y las dinámicas de los niveles de Ca2+ durante la inducción y el establecimiento de embriones somáticos y derivados de microsporas, se utilizaron tratamientos químicos y se detectaron los niveles de Ca2+ mediante sondas fluorescentes y sensores cameleon codificados genéticamente, visualizados con microscopía fluorescente y confocal. Observamos que el aumento de Ca2+ es un marcador temprano en la inducción de la embriogénesis in vitro y que los niveles de Ca2+ durante la embriogénesis in vitro son dinámicos en todos los sistemas estudiados. Además, las oscilaciones en los niveles de Ca2+ podrían estar relacionadas con los procesos de diferenciación que ocurren en las células inducidas una vez une el Ca2+ a la calmodulina. Mostramos que un aumento de Ca2+ dentro de un rango definido de concentración tiene un efecto positivo, dependiendo del sistema, en la producción de embriones, siendo más sensibles aquellos sistemas basados en suspensiones de células aisladas que aquellos que usan tejidos como explantes. Finalmente, estudiamos el papel de la calosa durante la embriogénesis somática, observando que la inhibición de la deposición de calosa impide el desarrollo embrionario, lo que sugiere una relación entre la formación de una barrera de calosa y el establecimiento de la identidad embrionaria en las células somáticas. / [CAT] El calci (Ca2+) és un catió essencial que juga un paper fonamental en tots els organismes vius. Des del punt de vista funcional, el Ca2+ actua com a un segon missatger que regula diferents processos cel·lulars. Treballs anteriors indiquen que la senyalització mitjançant el Ca2+ podria estar implicada en les primeres etapes de la inducció de l'embriogènesi in vitro de les plantes, però el paper real del Ca2+ en aquest procés encara és desconegut. Per això, el principal objectiu de la present Tesi és l'estudi del paper del Ca2+ en l'embriogènesi in vitro mitjançant dos sistemes in vitro: l'embriogènesi somàtica i l'embriogènesi de micròspores. Per tal de determinar la importància de l'homeòstasi del Ca2+ en la inducció de l'embriogènesi i les dinàmiques dels nivells de Ca2+ durant la inducció i l'establiment d'embrions somàtics i derivats de micròspores, es van utilitzar tractaments químics i es van detectar els nivells de Ca2+ mitjançant sondes fluorescents i sensors de cameleon codificats genèticament, visualitzats amb microscòpia fluorescent i confocal. Vam observar que l'augment de Ca2+ és un marcador primerenc en la inducció de l'embriogènesi in vitro i que els nivells de Ca2+ durant l'embriogènesi in vitro són dinàmics en tots els sistemes estudiats. A més, les oscil·lacions en els nivells de Ca2+ podrien estar relacionades amb els processos de diferenciació que tenen lloc en les cèl·lules induïdes una vegada uneix el Ca2+ a la calmodulina. Vam mostrar que un augment de Ca2+ dins d'un rang definit de concentració té un efecte positiu, depenent del sistema, en la producció d'embrions, essent més sensibles aquells sistemes basats en suspensions de cèl·lules aïllades que aquells que usen teixits com a explants. Finalment, vam estudiar el paper de la cal·losa durant l'embriogènesi somàtica, i vam observar que la inhibició de la deposició de cal·losa impedeix el desenvolupament embrionari, la qual cosa suggereix una relació entre la formació d'una barrera de cal·losa i l'establiment de la identitat embrionària en les cèl·lules somàtiques. / [EN] Calcium (Ca2+) is an essential cation that plays fundamental roles in all living organisms. From a functional point of view, Ca2+ acts as a second messenger that regulates different cellular processes. Previous works point to the fact that Ca2+ signaling may be involved in the early stages of induction of in vitro plant embryogenesis, but the actual role of Ca2+ in this process remained unveiled. Thus, the main goal of the present Thesis is to study the role of Ca2+ in in vitro embryogenesis using two in vitro systems: somatic embryogenesis and microspore embryogenesis. Chemical treatments and detection of Ca2+ with fluorescent probes and genetically-encoded cameleon sensors imaged by fluorescence and confocal microscopy were performed to determine the importance of Ca2+ homeostasis for induction of embryogenesis and the dynamics of Ca2+ levels during the induction and establishment of somatic and microspore-derived embryos. We observed that Ca2+ increase is an early marker of induction of in vitro embryogenesis and Ca2+ levels during in vitro embryogenesis are dynamic in all the systems we studied. Moreover, Ca2+ oscillations might be related to the differentiation processes that take place in the induced cells upon binding to calmodulin. We showed that Ca2+ increase within a defined range has system-specific positive effects in embryo yield, being more sensitive those systems using isolated cell suspensions rather than those using tissues as explants. Finally, we studied the role of callose during somatic embryogenesis, and we observed that inhibiting callose deposition prevents embryo development, which suggests a relationship between the formation of a callose barrier and the establishment of embryo identity in somatic cells. / Calabuig Serna, A. (2023). Multidisciplinary study of the role of calcium in plant in vitro embryogenesis [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/196022