Protocolos de comunicação seguros são essenciais em ambientes de automação industrial, onde falhas não detectadas na comunicação de dispositivos podem provocar danos irreparáveis à vida ou ao meio-ambiente. Esses protocolos seguros devem ser desenvolvidos de acordo com alguma norma de segurança, como a IEC 61508. Segundo ela, faz parte do processo de implementação destes protocolos, a escolha de técnicas adequadas de validação, entre elas a injeção de falhas, a qual deve considerar um modelo de falhas apropriado ao ambiente de operação do protocolo. Geralmente, esses ambientes são caracterizados pela existência de diversas formas de interferência elétrica e eletromagnética, as quais podem causar falhas nos sistemas eletrônicos existentes. Nos sistemas de comunicação de dados, isto pode levar a destruição do sinal de dados e causar estados de operação equivocados nos dispositivos. Assim, é preciso utilizar uma técnica de injeção de falhas que permita simular os tipos de erros de comunicação que podem ocorrer nos ambientes industriais. Dessa forma, será possível verificar o comportamento dos mecanismos de tolerância falhas na presença de falhas e assegurar o seu correto funcionamento. Para esta finalidade, este trabalho apresenta o desenvolvimento do injetor de falhas FITT para validação de protocolos de comunicação seguros. Esta ferramenta foi desenvolvida para ser utilizada com o sistema operacional Linux. O injetor faz uso do PF_RING, um módulo para o Kernel do Linux, que é responsável por realizar a comunicação direta entre as interfaces de rede e o injetor de falhas. Assim os pacotes não precisam passar pelas estruturas do Kernel do Linux, evitando que atrasos adicionais sejam inseridos no processo de recebimento e envio de mensagens. As funções de falhas desenvolvidas seguem o modelo de falhas de comunicação descrito na norma IEC 61508. Esse modelo é composto pelos erros de repetição, perda, inserção, sequência incorreta, endereçamento, corrupção de dados, atraso, mascaramento e falhas de memória em switches. / Safe communication protocols are essential in industrial automation environments, where undetected failures in the communication of devices can cause irreparable damage to life or to the environment. These safe protocols must be developed according to some safety standard, like IEC 61508. According to it, part of the process of implementing these protocols is to select appropriate techniques for validation, including the fault injection, which should consider an appropriate fault model for the operating environment of the protocol. Generally, these environments are characterized by the existence of various forms of electric and electromagnetic interference, which can cause failures in existing electronic systems. In data communication systems, this can lead to the destruction of the data signal and cause erroneous operation states in the devices. Thus, it is necessary to use a fault injection technique that allows simulating the types of communication errors that may occur in industrial environments. So, it will be possible to verify the behavior of the fault tolerance mechanisms in the presence of failures and ensure its correct functioning. For this purpose, this work presents the development of FITT fault injector for validation of safety communication protocols. This tool was developed to be used with Linux operating system. The fault injector makes use of PF_RING, a module for the Linux Kernel and that is responsible to perform the direct communication between the network interfaces and the fault injector. Thus the packages do not need to go through the Linux Kernel structures, avoiding additional delays to be inserted into the process of receiving and sending messages. The developed fault injection functions follow the communication fault model described in the IEC61508 standard, composed by the errors of repetition, loss, insertion, incorrect sequence, addressing, data corruption, delay, masking and memory failures within switches. The fault injection tests applied with this model allow to properly validate the fault tolerance mechanisms of safety protocols.

Honey bee colonies all over Europe and North America have been declining dramatically for over three decades and is continuing to do so which is causing significant threats to economy, agriculture and ecosystems. The main reason behind the declining colonies is an ectoparasitic mite known as Varroa destructor and viruses vectored by the mite. In previous studies, it has been suggested that a unique mite-resistant subpopulation of honey bees (Apis mellifera) in Gotland, Sweden have developed adaptive tolerance to these viruses as they have managed to survive high mite infestation through natural selection without any mite control treatment. This indicates that there might be a correlation between resistance to Varroa destructor and virus tolerance. This project examined if a correlation between virus resistance and/or virus tolerance can be observed in Varroa-resistant honey bees from unique subpopulations in Europe covering Sweden, Norway, France and Netherlands. Results showed that no correlation could be established based on the findings in this project. However, significant differences in winter colony survival numbers between mite-resistant and mite-susceptible honey bees suggest that tolerance mechanisms could be present in these subpopulations. Further studies are required to verify this hypothesis.

Protocolos de comunicação seguros são essenciais em ambientes de automação industrial, onde falhas não detectadas na comunicação de dispositivos podem provocar danos irreparáveis à vida ou ao meio-ambiente. Esses protocolos seguros devem ser desenvolvidos de acordo com alguma norma de segurança, como a IEC 61508. Segundo ela, faz parte do processo de implementação destes protocolos, a escolha de técnicas adequadas de validação, entre elas a injeção de falhas, a qual deve considerar um modelo de falhas apropriado ao ambiente de operação do protocolo. Geralmente, esses ambientes são caracterizados pela existência de diversas formas de interferência elétrica e eletromagnética, as quais podem causar falhas nos sistemas eletrônicos existentes. Nos sistemas de comunicação de dados, isto pode levar a destruição do sinal de dados e causar estados de operação equivocados nos dispositivos. Assim, é preciso utilizar uma técnica de injeção de falhas que permita simular os tipos de erros de comunicação que podem ocorrer nos ambientes industriais. Dessa forma, será possível verificar o comportamento dos mecanismos de tolerância falhas na presença de falhas e assegurar o seu correto funcionamento. Para esta finalidade, este trabalho apresenta o desenvolvimento do injetor de falhas FITT para validação de protocolos de comunicação seguros. Esta ferramenta foi desenvolvida para ser utilizada com o sistema operacional Linux. O injetor faz uso do PF_RING, um módulo para o Kernel do Linux, que é responsável por realizar a comunicação direta entre as interfaces de rede e o injetor de falhas. Assim os pacotes não precisam passar pelas estruturas do Kernel do Linux, evitando que atrasos adicionais sejam inseridos no processo de recebimento e envio de mensagens. As funções de falhas desenvolvidas seguem o modelo de falhas de comunicação descrito na norma IEC 61508. Esse modelo é composto pelos erros de repetição, perda, inserção, sequência incorreta, endereçamento, corrupção de dados, atraso, mascaramento e falhas de memória em switches. / Safe communication protocols are essential in industrial automation environments, where undetected failures in the communication of devices can cause irreparable damage to life or to the environment. These safe protocols must be developed according to some safety standard, like IEC 61508. According to it, part of the process of implementing these protocols is to select appropriate techniques for validation, including the fault injection, which should consider an appropriate fault model for the operating environment of the protocol. Generally, these environments are characterized by the existence of various forms of electric and electromagnetic interference, which can cause failures in existing electronic systems. In data communication systems, this can lead to the destruction of the data signal and cause erroneous operation states in the devices. Thus, it is necessary to use a fault injection technique that allows simulating the types of communication errors that may occur in industrial environments. So, it will be possible to verify the behavior of the fault tolerance mechanisms in the presence of failures and ensure its correct functioning. For this purpose, this work presents the development of FITT fault injector for validation of safety communication protocols. This tool was developed to be used with Linux operating system. The fault injector makes use of PF_RING, a module for the Linux Kernel and that is responsible to perform the direct communication between the network interfaces and the fault injector. Thus the packages do not need to go through the Linux Kernel structures, avoiding additional delays to be inserted into the process of receiving and sending messages. The developed fault injection functions follow the communication fault model described in the IEC61508 standard, composed by the errors of repetition, loss, insertion, incorrect sequence, addressing, data corruption, delay, masking and memory failures within switches. The fault injection tests applied with this model allow to properly validate the fault tolerance mechanisms of safety protocols.

Protocolos de comunicação seguros são essenciais em ambientes de automação industrial, onde falhas não detectadas na comunicação de dispositivos podem provocar danos irreparáveis à vida ou ao meio-ambiente. Esses protocolos seguros devem ser desenvolvidos de acordo com alguma norma de segurança, como a IEC 61508. Segundo ela, faz parte do processo de implementação destes protocolos, a escolha de técnicas adequadas de validação, entre elas a injeção de falhas, a qual deve considerar um modelo de falhas apropriado ao ambiente de operação do protocolo. Geralmente, esses ambientes são caracterizados pela existência de diversas formas de interferência elétrica e eletromagnética, as quais podem causar falhas nos sistemas eletrônicos existentes. Nos sistemas de comunicação de dados, isto pode levar a destruição do sinal de dados e causar estados de operação equivocados nos dispositivos. Assim, é preciso utilizar uma técnica de injeção de falhas que permita simular os tipos de erros de comunicação que podem ocorrer nos ambientes industriais. Dessa forma, será possível verificar o comportamento dos mecanismos de tolerância falhas na presença de falhas e assegurar o seu correto funcionamento. Para esta finalidade, este trabalho apresenta o desenvolvimento do injetor de falhas FITT para validação de protocolos de comunicação seguros. Esta ferramenta foi desenvolvida para ser utilizada com o sistema operacional Linux. O injetor faz uso do PF_RING, um módulo para o Kernel do Linux, que é responsável por realizar a comunicação direta entre as interfaces de rede e o injetor de falhas. Assim os pacotes não precisam passar pelas estruturas do Kernel do Linux, evitando que atrasos adicionais sejam inseridos no processo de recebimento e envio de mensagens. As funções de falhas desenvolvidas seguem o modelo de falhas de comunicação descrito na norma IEC 61508. Esse modelo é composto pelos erros de repetição, perda, inserção, sequência incorreta, endereçamento, corrupção de dados, atraso, mascaramento e falhas de memória em switches. / Safe communication protocols are essential in industrial automation environments, where undetected failures in the communication of devices can cause irreparable damage to life or to the environment. These safe protocols must be developed according to some safety standard, like IEC 61508. According to it, part of the process of implementing these protocols is to select appropriate techniques for validation, including the fault injection, which should consider an appropriate fault model for the operating environment of the protocol. Generally, these environments are characterized by the existence of various forms of electric and electromagnetic interference, which can cause failures in existing electronic systems. In data communication systems, this can lead to the destruction of the data signal and cause erroneous operation states in the devices. Thus, it is necessary to use a fault injection technique that allows simulating the types of communication errors that may occur in industrial environments. So, it will be possible to verify the behavior of the fault tolerance mechanisms in the presence of failures and ensure its correct functioning. For this purpose, this work presents the development of FITT fault injector for validation of safety communication protocols. This tool was developed to be used with Linux operating system. The fault injector makes use of PF_RING, a module for the Linux Kernel and that is responsible to perform the direct communication between the network interfaces and the fault injector. Thus the packages do not need to go through the Linux Kernel structures, avoiding additional delays to be inserted into the process of receiving and sending messages. The developed fault injection functions follow the communication fault model described in the IEC61508 standard, composed by the errors of repetition, loss, insertion, incorrect sequence, addressing, data corruption, delay, masking and memory failures within switches. The fault injection tests applied with this model allow to properly validate the fault tolerance mechanisms of safety protocols.

L'évolution des systèmes pendant leur vie opérationnelle est incontournable. Les systèmes sûrs de fonctionnement doivent évoluer pour s'adapter à des changements comme la confrontation à de nouveaux types de fautes ou la perte de ressources. L'ajout de cette dimension évolutive à la fiabilité conduit à la notion de résilience informatique. Parmi les différents aspects de la résilience, nous nous concentrons sur l'adaptativité. La sûreté de fonctionnement informatique est basée sur plusieurs moyens, dont la tolérance aux fautes à l'exécution, où l'on attache des mécanismes spécifiques (Fault Tolerance Mechanisms, FTMs) à l'application. A ce titre, l'adaptation des FTMs à l'exécution s'avère un défi pour développer des systèmes résilients. Dans la plupart des travaux de recherche existants, l'adaptation des FTMs à l'exécution est réalisée de manière préprogrammée ou se limite à faire varier quelques paramètres. Tous les FTMs envisageables doivent être connus dès le design du système et déployés et attachés à l'application dès le début. Pourtant, les changements ont des origines variées et, donc, vouloir équiper un système pour le pire scénario est impossible. Selon les observations pendant la vie opérationnelle, de nouveaux FTMs peuvent être développés hors-ligne, mais intégrés pendant l'exécution. On dénote cette capacité comme adaptation agile, par opposition à l'adaptation préprogrammée. Dans cette thèse, nous présentons une approche pour développer des systèmes sûrs de fonctionnement flexibles dont les FTMs peuvent s'adapter à l'exécution de manière agile par des modifications à grain fin pour minimiser l'impact sur l'architecture initiale. D'abord, nous proposons une classification d'un ensemble de FTMs existants basée sur des critères comme le modèle de faute, les caractéristiques de l'application et les ressources nécessaires. Ensuite, nous analysons ces FTMs et extrayons un schéma d'exécution générique identifiant leurs parties communes et leurs points de variabilité. Après, nous démontrons les bénéfices apportés par les outils et les concepts issus du domaine du génie logiciel, comme les intergiciels réflexifs à base de composants, pour développer une librairie de FTMs adaptatifs à grain fin. Nous évaluons l'agilité de l'approche et illustrons son utilité à travers deux exemples d'intégration : premièrement, dans un processus de développement dirigé par le design pour les systèmes ubiquitaires et, deuxièmement, dans un environnement pour le développement d'applications pour des réseaux de capteurs. / Evolution during service life is mandatory, particularly for long-lived systems. Dependable systems, which continuously deliver trustworthy services, must evolve to accommodate changes e.g., new fault tolerance requirements or variations in available resources. The addition of this evolutionary dimension to dependability leads to the notion of resilient computing. Among the various aspects of resilience, we focus on adaptivity. Dependability relies on fault tolerant computing at runtime, applications being augmented with fault tolerance mechanisms (FTMs). As such, on-line adaptation of FTMs is a key challenge towards resilience. In related work, on-line adaption of FTMs is most often performed in a preprogrammed manner or consists in tuning some parameters. Besides, FTMs are replaced monolithically. All the envisaged FTMs must be known at design time and deployed from the beginning. However, dynamics occurs along multiple dimensions and developing a system for the worst-case scenario is impossible. According to runtime observations, new FTMs can be developed off-line but integrated on-line. We denote this ability as agile adaption, as opposed to the preprogrammed one. In this thesis, we present an approach for developing flexible fault-tolerant systems in which FTMs can be adapted at runtime in an agile manner through fine-grained modifications for minimizing impact on the initial architecture. We first propose a classification of a set of existing FTMs based on criteria such as fault model, application characteristics and necessary resources. Next, we analyze these FTMs and extract a generic execution scheme which pinpoints the common parts and the variable features between them. Then, we demonstrate the use of state-of-the-art tools and concepts from the field of software engineering, such as component-based software engineering and reflective component-based middleware, for developing a library of fine-grained adaptive FTMs. We evaluate the agility of the approach and illustrate its usability throughout two examples of integration of the library: first, in a design-driven development process for applications in pervasive computing and, second, in a toolkit for developing applications for WSNs.

En raison des activités anthropiques croissantes, de larges sites sont contaminés par les métaux lourds qui affectent les systèmes biologiques. La souche Oidiodendron maius Zn pourrait être un organisme intéressant dans un programme de bioremédiation étant à la fois un champignon mycorhizien éricoïde et une souche tolérante aux métaux lourds. Pour comprendre les mécanismes de la tolérance de cette souche, trois approches différentes ont été menées.La première approche a abouti à la génération de mutants du gène superoxyde dismutase 1 (OmSOD1). Il s'agit de la première délétion d'un gène par recombinaison homologue chez un champignon mycorhizien. Nous démontrons que l'absence d'OmSOD1 cause un déséquilibre dans l'homéostasie rédox et un changement dans le dialogue entre le champignon et sa plante hôte.La deuxième approche a été basée sur la complémentation fonctionnelle d'un mutant de levure en utilisant une banque d'ADNc d'O. maius. Nous décrivons les premiers transporteurs d'un champignon mycorhizien éricoïde capables de conférer la tolérance au Zn dans des levures. Deux gènes ont été isolés et nommés OmCDF et OmFET. L'expression hétérologue de ces deux gènes dans différents mutants de levure a permis de conférer la tolérance au Zn. De plus, OmCDF a également permis de conférer la tolérance au Co. Nos données suggérent que OmCDF est un transporteur de Zn responsable du transfert du Zn cytoplasmique vers le réticulum endoplasmique, tandis que l'expression d'OmFET pourrait neutraliser la toxicité engendrée par le Zn en augmentant le contenu du Fe dans la cellule. La troisième approche a concerné le criblage d'une collection de mutants aléatoires d'O. maius sur Zn, Cd et ménadione. Nous décrivons la caractérisation d'un mutant dans le gène nmr. Dans ce mutant, une diminution de la teneur en glutamine et asparagine, ainsi qu'une réduction de l'activité de la glutamine synthétase ont été enregistrées. Les liens possibles entre la tolérance au stress oxydatif et le métabolisme azoté sont discutés. / Due to increasing anthropogenic activities, large areas are highly contaminated by heavy metals which are affecting biological systems. Oidiodendron maius strain Zn could be an interesting organism in a bioremediation program being both an ericoid mycorrhizal fungus and a heavy metal-tolerant strain. To understand the mechanisms underlying the oxidative stress tolerance of this strain, three different approaches were used. The first approach allowed us to obtain superoxide dismutase 1 (SOD1) null mutants. The most important technical advance in this work was the first successful disruption of a gene by homologous recombination in a mycorrhizal fungus. We demonstrate that the lack of OmSOD may cause an imbalance in the redox homeostasis and an alteration in the delicate dialogue between the fungus and its host plant. The second approach was based on a yeast functional complementation screening using an O. maius cDNA library. In this work we report the first transporters of an ericoid mycorrhizal fungus capable of conferring Zn tolerance to yeast transformants. Two full-length cDNAs were isolated and named OmCDF and OmFET. The heterologous expression of these two genes in various yeast mutants conferred resistance to zinc. Additionally, OmCDF expression also conferred Co tolerance. We provide evidence that OmCDF functions as a Zn transporter responsible for relocating cytoplasmic Zn into the endoplasmic reticulum, whereas expression of OmFET could counteract Zn toxicity by increasing Fe content of cells. The third approach consisted in the screening of a collection of O. maius random-mutants on Zn, Cd and menadione. We report the characterization of an O. maius-mutant that carries a mutation in the nmr gene. In this mutant, a decrease of glutamine and asparagine pools, and a reduction of the activity of glutamine synthase were recorded. Possible links between the oxidative stress tolerance and the nitrogen metabolism are discussed.

Made available in DSpace on 2014-08-20T13:25:40Z (GMT). No. of bitstreams: 1 Tese_Denise_dos_Santos_colaresl.pdf: 673518 bytes, checksum: 7c45d65e0fc8e9a1e7438b33e7da2bab (MD5) Previous issue date: 2009-04-23 / Aluminum is the most abundant metal in the earth s crust. Under acidic conditions, aluminum is solublized to its ionic form, which shows toxicity to plants. Aluminum rapidly inhibits root elongation and subsequently the uptake of water and nutrients, resulting in significant reduction of crop production on acid soils. Rice is one of the most aluminum-tolerant species among economically important crops. However, the physiological mechanism responsible for the high aluminum tolerance in rice has not been elucidated. On the other hand, rice genome is a model for the Poaceae and shows high sinteny with this family of plants. In this work, 30 rice cultivars were evaluated under four aluminum concentrations in hidroponic system. The genetic variability between the rice cultivars was evaluated through multivariated analysis. According to the tolerance response observed, 10 genotypes were selected to be evaluated in relation to a dose x time of exposition experiment. Finally, the expression of the gene OsFRDL1 was quantified in two rice cultivars differing in aluminum tolerance. There was variability in relation to aluminum tolerance between the 30 rice cultivars evaluated. The most tolerant genotypes were IAC 500, BRS Liderança and BRS Curinga and the sensitive ones were BR-IRGA 410, IAS 12-9 Formosa and Arroz da Terra. The tolerant cultivars IAC 500, BRS Liderança and BRS Curinga showed high genetic similarity and are promising genotypes for crosses aiming to increase aluminum tolerance in the progenies. Cultivars responded in a different way to the dose x time of exposition to aluminum experiment. Forty-eight hours of exposition to a solution containing an aluminum concentration of 14 mg L-1 showed to be the best combination of treatments to perform the screening of tolerant and sensitive cultivars. The expression of the gene OsFRDL1 was higher in the aluminum tolerant cultivar Farroupilha than in the aluminum-sensitive cultivar BRIRGA 410. / O alumínio é o metal mais abundante da crosta terrestre, estando presente, em sua maior parte, sob formas não prejudiciais às plantas. Condições de reduzido pH, entretanto, originam a espécie fitotóxica Al3+, que se constitui em um dos principais fatores limitantes à produção agrícola em solos ácidos. O principal sintoma da toxidez causada por alumínio é um rápido decréscimo no crescimento radicular, dificultando a absorção de água e nutrientes pela planta. O arroz é considerado, dentre as culturas de importância econômica, como uma das mais tolerantes a esse metal. Apesar disso, os mecanismos dessa elevada tolerância não são ainda conhecidos. Por outro lado, seu genoma é modelo para as poáceas, além de apresentar elevada sintenia com essa família de plantas. Com o objetivo de caracterizar 30 cultivares de arroz quanto à tolerância ao alumínio, as mesmas foram submetidas a quatro níveis do metal em solução nutritiva. Através de análise multivariada, foi avaliada a variabilidade existente entre os genótipos. Com base na resposta ao estresse, dez cultivares foram escolhidas para serem analisadas em relação ao aumento no tempo de exposição a diferentes doses de alumínio. Por fim, foi avaliada a expressão do gene OsFRDL1 em dois genótipos contrastantes quanto à tolerância ao alumínio. Foi verificada variabilidade em relação à tolerância ao alumínio entre as 30 cultivares. As mais tolerantes foram IAC 500, BRS Liderança e BRS Curinga, enquanto as mais sensíveis foram BR-IRGA 410, IAS 12-9 Formosa e Arroz da Terra. BRS Curinga, BRS Liderança e IAC 500, tolerantes ao alumínio, apresentaram elevada similaridade genética e são promissores para serem utilizados em cruzamentos que visem à obtenção de progênies superiores para tolerância ao alumínio. Através do experimento que combinou doses de alumínio x tempos de exposição foi possível verificar que os genótipos respondem de forma diferenciada ao aumento no tempo de exposição às diferentes concentrações de alumínio. A melhor combinação para diferenciar genótipos foi de 48 horas de exposição a 14 mg L-1 de alumínio. A expressão do gene OsFRDL1 foi maior na cultivar Farroupilha, tolerante ao alumínio, do que na BR-IRGA 410, sensível ao metal.

Tesis por compendio / [ES] La sequía y la salinidad son los factores ambientales que más afectan a las plantas, aunque en general, las plantas mediterráneas están bien adaptadas a las condiciones adversas. Las previsiones estiman que debido al calentamiento global las condiciones ambientales se volverán más estresantes, especialmente en las zonas semi-áridas y áridas como muchas áreas de la Península Ibérica. Estas condiciones pueden afectar a la presencia de muchas especies silvestres, en especial, de las que ya de por si están amenazadas, son raras o endémicas. Tanto la sequía como el estrés salino provocan la activación de una serie de mecanismos de defensa o respuesta de las plantas, que incluyen entre otros, el control del transporte iónico, la acumulación de solutos compatibles u osmolitos, y la activación de sistemas antioxidantes. Para contribuir a la conservación y/o reintroducción de las especies de interés en hábitats prioritarios se ha realizado un estudio multidisciplinar abarcando los parámetros que pueden afectar sus poblaciones, como el clima, el suelo, y la vegetación acompañante, junto a estudios comparativos sobre las respuestas a la sequía y a la salinidad. Para entender mejor los mecanismos de tolerancia se han incluido en el estudio además de los taxones de interés conservacionista, especies relacionadas genéticamente con diferentes niveles de tolerancia. El estudio presenta dos objetivos principales: i) establecer la tolerancia relativa al estrés hídrico y salino de las especies en base a su distribución en la naturaleza y en los análisis realizados en campo y, en función de la inhibición relativa de su crecimiento bajo condiciones provocadas de estrés; y, ii) evaluar los cambios bioquímicos inducidos por el estrés analizando diferentes mecanismos de respuesta (inhibición de la fotosíntesis, transporte iónico, acumulación de osmolitos, mecanismos antioxidantes). / [CA] La sequera i la salinitat són els factors ambientals que més afecten les plantes, encara que en general, les plantes mediterrànies estan ben adaptades a les condicions adverses. Les previsions estimen que a causa del calfament global les condicions ambientals es tornaran més estressants, especialment en les zones semi-àrides i àrides com moltes àrees de la Península Ibèrica. Aquestes condicions poden afectar la presència de moltes espècies silvestres, especialment, de les que ja de per si estan amenaçades, són rares o endèmiques. Tant la sequera com l'estrès salí provoquen l'activació d'una sèrie de mecanismes de defensa o resposta de les plantes, que inclouen entre altres, el control del transport iònic, l'acumulació de soluts compatibles u osmolits, i l'activació de sistemes antioxidants. Per a contribuir a la conservació i/o reintroducció de les espècies d'interès en hàbitats prioritaris s'ha realitzat un estudi multidisciplinari abastant els paràmetres que poden afectar les seues poblacions, com el clima, el sòl, i la vegetació acompanyant, al costat d'estudis comparatius sobre les respostes a la sequera i a la salinitat. Per a entendre millor els mecanismes de tolerància s'han inclòs en l'estudi a més dels tàxons d'interès conservacionista, espècies relacionades genèticament amb diferents nivells de tolerància. L'estudi presenta dos objectius principals: i) establir la tolerància relativa a l'estrès hídric i salí de les espècies sobre la base de la seua distribució en la naturalesa i en les anàlisis realitzades en camp i, en funció de la inhibició relativa del seu creixement sota condicions provocades d'estrès; i, ii) avaluar els canvis bioquímics induïts per l'estrès analitzant diferents mecanismes de resposta (inhibició de la fotosíntesi, transport iònic, acumulació de osmolits, mecanismes antioxidants). / [EN] Drought and salinity are the environmental factors that most affect plants, although in general Mediterranean plants are well adapted to adverse conditions. Predictions estimate that, due to global warming, environmental conditions will become more stressful, especially in semi-arid and arid areas, such as many areas of the Iberian Peninsula. These conditions may affect the presence of many wild species, especially those that are already threatened, rare or endemic. Both drought and salt stress cause the activation of a series of defence or response mechanisms in plants, which include, among others, the control of ionic transport, the accumulation of compatible solutes or osmolytes, and the activation of antioxidant systems. To contribute to the conservation and/or reintroduction of species of interest in priority habitats, a multidisciplinary study has been carried out covering parameters that may affect their populations, such as climate, soil and accompanying vegetation, together with comparative studies on responses to drought and salinity. To better understand tolerance mechanisms, genetically related species with different levels of tolerance have been included in the study, in addition to taxa of conservation interest. The study has two main objectives: i) to establish the relative tolerance to water and salt stress of the species according to their distribution in nature and based on field analyses and, according to the relative inhibition of their growth under stress-induced conditions; and, ii) to evaluate stress-induced biochemical changes by analysing different mechanisms (inhibition of photosynthesis, ionic transport, osmolyte accumulation, antioxidant mechanisms). / This research was partially funded by Project AICO/2017/039 from the Generalitat Valenciana. / González Orenga, S. (2021). Mecanismos de tolerancia a estrés salino e hídrico en plantas endémicas, raras o amenazadas [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/168443 / TESIS / Compendio