Destinée des S-RNases dans les tubes polliniques lors des croisements compatibles et incompatibles

L’auto-incompatibilité (AI) est la capacité génétiquement déterminée d’une plante fertile de rejeter son propre pollen. Chez les Solanacées l’AI dépend des éléments d’un locus fort complexe (locus S) multigénique. L’élément du locus-S exprimé dans le pistil est une ribonucléase (S-RNase) dont le rôle est de dégrader l’ARN chez le pollen self, tandis que l’élément du locus S exprimé dans le pollen est un ensemble de protéines du type F-box, qui sont normalement impliquées dans la dégradation des protéines. Cependant, comment les S-RNases self restent actives lors des croisements incompatibles et comment les S-RNases non-self sont inactivées lors des croisements compatibles ce n’est encore pas clair. Un modèle propose que les S-RNases non-self soient dégradées lors des croisements compatibles. Un autre modèle propose que toutes les S-RNases, self et non-self, soient d'abord séquestrées à l’intérieur d’une vacuole, et elles y resteraient lors des croisements compatibles. Lors de croisements incompatibles, par contre, elles seraient relâchées dans le cytoplasme, où elles pourront exercer leur action cytotoxique. Notre étude tente de répondre à ces questions. Notamment, nous cherchons à mettre en évidence la localisation vacuolaire et/ou cytoplasmique des S-RNases et leur concentration par immunolocalisation, en utilisant un anticorps ciblant la S11-RNase de Solanum chacoense et la microcopie électronique à transmission. Nos résultats montrent que la densité de marquage observée pour les S-RNases cytoplasmiques est significativement plus haute dans les tubes incompatibles que dans ceux compatibles ce qui nous indique que pour qu’un tube pollinique soit compatible il doit contenir une faible densité de S-RNase cytoplasmique.

Les instabilités magnétohydrodynamiques dans EULAG-MHD.

Les mécanismes qui entretiennent le cycle magnétique solaire sont encore aujourd’hui relativement mal compris. Entre autres, certains travaux suggèrent la présence d’insta- bilités magnétohydrodynamiques qui pourraient avoir une influence significative sur la période du cycle par leur capacité à accélérer la destruction des structures magnétiques à grandes échelles. Nous analysons la présence des instabilités au sein des simulations effectuées à l’aide du modèle EULAG-MHD en utilisant premièrement une méthodologie basée sur un proxy spécifique associé à l’instabilité et en le comparant à un proxy similaire, mais pour le cycle magnétique solaire observé dans notre modèle. Cette méthodologie fait ressortir une évolution temporellement cyclique du proxy de l’instabilité avec des amplitudes similaires au proxy du cycle magnétique, mais présentant un léger déphasage. Nous poursuivons cette analyse en appliquant une méthode se basant sur le découpage de “zones instables” via le critère de Tayler dans la zone stable de notre modèle. L’application expose une migration équatoriale d’une zone instable qui débute à très hautes latitudes aux pôles, passe par le champ toroïdal classique, accélère et atteint l’équateur. Cette zone instable semble accélérer la destruction du champ magnétique présent, laissant place au nouveau champ pour la prochaine demie-période du cycle. La combinaison de ces deux analyses permet d’énoncer un scénario plausible qui inclut les effets d’une telle instabilité sur le cycle magnétique ainsi que sur la stabilité globale de notre simulation. Dans ce scénario, il est important de noter que les inversions de polarités semblent indépendantes de cette instabilité, qui ne ferait qu’accélérer le processus de destruction du champ déjà en place.

La planification métropolitaine et le transit-oriented development (TOD) : les nouveaux instruments de la gouvernance du Grand Montréal

Cette thèse croise les concepts de planification, de gouvernance et de transit-oriented development (TOD) par une étude de la production, de la mise en débat et de l'adoption du plan métropolitain d'aménagement et de développement (PMAD) de la Communauté métropolitaine de Montréal (CMM). Elle expose les résultats de quatre années de recherche qualitative sur les impacts de l'épisode du PMAD et de la stratégie TOD de la CMM sur les pratiques planificatrices et les processus décisionnels du Grand Montréal à l'échelle métropolitaine. Elle révèle que la planification métropolitaine et l'objectif de coordination du transport et de l'aménagement en général ainsi que le PMAD et le concept de TOD en particulier y sont des instruments de gouvernance. Les chapitres 2, 3 et 4 présentent la problématique, le terrain d'enquête et la démarche méthodologique de cette recherche. Le chapitre 5 relate l'épisode du PMAD en analysant son contenu, les procédures par lesquelles la CMM l'a produit, mis en débat et adopté, les réactions des parties prenantes de la région quant à ces aspects et la façon dont elles comptent assurer le suivi de sa mise en œuvre. Le chapitre 6 illustre comment cet épisode a fait du PMAD un instrument de gouvernance pour le Grand Montréal en décortiquant le rôle de la participation publique, des médias, des acteurs des milieux régional et local, des élus, de la CMM et de la société civile de la région au sein de ce processus de changement de registre de la planification et de la gouvernance les déployant sur des bases plus stratégiques et collaboratives. Le chapitre 7 montre que cet épisode a aussi fait du TOD un instrument de gouvernance pour le Grand Montréal en détaillant les tenants et aboutissants du processus d'appropriation, de marchand(is)age et d'instrumentalisation du concept par les élites politiques et techniques à des fins de marketing territorial et de construction de capital politique ouvrant la voie à la stabilisation d'une gouvernance en matière d'aménagement métropolitain. Il se dégage de cette thèse que ces profondes transformations que subissent actuellement la planification et la gouvernance exacerbent le caractère symbiotique de la relation qui les unit.

Determination of the laser-induced damage threshold of bulk polymer samples at 1.06 mu m using the pulsed photothermal deflection technique

A pulsed Nd-YAG laser beam is used to produce a transient refractive index gradient in air adjoining the plane surface of the sample material. This refractive index gradient is probed by a continuous He-Ne laser beam propagating parallel to the sample surface. The observed deflection signals produced by the probe beam exhibit drastic variations when the pump laser energy density crosses the damage threshold for the sample. The measurements are used to estimate the damage threshold for a few polymer samples. The present values are found to be in good agreement with those determined by other methods.

Heat stress response for physiological traits in dairy and dual purpose cattle populations on phenotypic and genetic scales

The main objective of this thesis was to determine the potential impact of heat stress (HS) on physiological traits of lactating cows and semen quality of bulls kept in a temperate climate. The thesis is comprised of three studies. An innovative statistical modeling aspect common to all three studies was the application of random regression methodology (RRM) to study the phenotypic and genetic trajectory of traits in dependency of a continuous temperature humidity index (THI). In the first study, semen quality and quantity traits of 562 Holstein sires kept on an AI station in northwestern Germany were analyzed in the course of THI calculated from data obtained from the nearest weather station. Heat stress was identified based on a decline in semen quality and quantity parameters. The identified general HS threshold (THI = 60) and the thermoneutal zone (THI in the range from 50 to 60) for semen production were lower than detected in studies conducted in tropical and subtropical climates. Even though adult bulls were characterized by higher semen productivity compared to younger bulls, they responded with a stronger semen production loss during harsh environments. Heritabilities (low to moderate range) and additive genetic variances of semen characteristics varied with different levels of THI. Also, based on genetic correlations genotype, by environment interactions were detected. Taken together, these findings suggest the application of specific selection strategies for specific climate conditions. In the second study, the effect of the continuous environmental descriptor THI as measured inside the barns on rectal temperatures (RT), skin temperatures (ST), vaginal temperatures (VT), respiration rates (RR), and pulse rate (PR) of lactating Holstein Friesian (HF) and dual-purpose German black pied cattle (DSN) was analyzed. Increasing HS from THI 65 (threshold) to THI 86 (maximal THI) resulted in an increase of RT by 0.6 °C (DSN) and 1 °C (HF), ST by 3.5 °C (HF) and 8 °C (DSN), VT by 0.3 °C (DSN), and RR by 47 breaths / minute (DSN), and decreased PR by 7 beats / minute (DSN). The undesired effects of rising THI on physiological traits were most pronounced for cows with high levels of milk yield and milk constituents, cows in early days in milk and later parities, and during summer seasons in the year 2014. In the third study of this dissertation, the genetic components of the cow’s physiological responses to HS were investigated. Heat stress was deduced from indoor THI measurements, and physiological traits were recorded on native DSN cows and their genetically upgraded crosses with Holstein Friesian sires in two experimental herds from pasture-based production systems reflecting a harsh environment of the northern part of Germany. Although heritabilities were in a low range (from 0.018 to 0.072), alterations of heritabilities, repeatabilities, and genetic components in the course of THI justify the implementation of genetic evaluations including heat stress components. However, low repeatabilities indicate the necessity of using repeated records for measuring physiological traits in German cattle. Moderate EBV correlations between different trait combinations indicate the potential of selection for one trait to simultaneously improve the other physiological attributes. In conclusion, bulls of AI centers and lactating cows suffer from HS during more extreme weather conditions also in the temperate climate of Northern Germany. Monitoring physiological traits during warm and humid conditions could provide precious information for detection of appropriate times for implementation of cooling systems and changes in feeding and management strategies. Subsequently, the inclusion of these physiological traits with THI specific breeding values into overall breeding goals could contribute to improving cattle adaptability by selecting the optimal animal for extreme hot and humid conditions. Furthermore, the recording of meteorological data in close distance to the cow and visualizing the surface body temperature by infrared thermography techniques might be helpful for recognizing heat tolerance and adaptability in cattle.

Augmented state Kalman filtering for AUV navigation

Addresses the problem of estimating the motion of an autonomous underwater vehicle (AUV), while it constructs a visual map ("mosaic" image) of the ocean floor. The vehicle is equipped with a down-looking camera which is used to compute its motion with respect to the seafloor. As the mosaic increases in size, a systematic bias is introduced in the alignment of the images which form the mosaic. Therefore, this accumulative error produces a drift in the estimation of the position of the vehicle. When the arbitrary trajectory of the AUV crosses over itself, it is possible to reduce this propagation of image alignment errors within the mosaic. A Kalman filter with augmented state is proposed to optimally estimate both the visual map and the vehicle position

Impacto del conflicto armado en la frontera colombo-ecuatoriana y las implicaciones en sus relaciones diplomáticas a partir de la implementación del Plan Colombia hasta diciembre de 2009

Históricamente, las fronteras colombianas han sido porosas, frágiles y descuidadas desde una perspectiva política. La extrema pobreza y la ausencia de instituciones estatales han dejado a las poblaciones vulnerables ante diversos actores armados y a merced de las actividades ilícitas, que inevitablemente se desbordan y afectan los territorios vecinos. El desborde de los efectos del conflicto armado a territorio ecuatoriano, los enfrentamientos e incursiones del ejército colombiano, y la presencia de actores no estatales como los grupos al margen de la ley, han hecho que las relaciones bilaterales se minen, dañando lo que alguna vez fue una cordialidad constructiva entre Colombia y Ecuador. Para analizar esta problemática, se utilizaron las teorías de las relaciones internacionales de Interdependencia y seguridad cooperativa.

How do I get Word 2010 table headers to repeat on subsequent pages

When a table crosses on to 2 or more pages it can be very useful to have the headers appear on all subsequent pages. This video shows how.

En inglés.

El proyecto pretende acercar a los alumnos a una lengua extranjera de forma divertida y atractiva, y despertar su interés por otras culturas. Los objetivos son romper las barreras de comunicación creadas por las diferentes lenguas; motivar a los alumnos en la búsqueda de producciones artísticas en lengua extranjera; favorecer el intercambio de experiencias y creaciones artísticas entre los ciclos; y disfrutar, mejorando la relación entre los miembros de la comunidad educativa. Entre las actividades, destacan audiciones para fijar la pronunciación; representaciones teatrales; murales sobre aspectos socioculturales del Reino Unido; aprendizaje de juegos y canciones para la representación de Música en Inglés; lectura de libros; correspondencia con niños del colegio International School of Madrid; Jornadas de cine en inglés; English Festival; talleres para Infantil; visita de exposiciones, como la de la biblioteca del centro; y el periódico The Pencil, que recoge las producciones de los alumnos expuestas en los pasillos del centro. Se elaboran materiales, como carteles señalizadores; libro de canciones; cartas en inglés; reproducción de monumentos y objetos típicos ingleses, para decorar los pabellones del centro; materiales elaborados en los talleres; el periódico The Pencil; reportaje fotográfico de las actividades para la exposición; vídeo sobre las Jornadas Culturales; e información y fotos sobre las Jornadas Culturales para la página web del centro. Se incluyen como anexos los murales y fichas de vocabulario, letras de canciones y cartas en inglés, tarjetas, móvil, juego Noughs and crosses, memory game, A yellow submarine, dominó, banderas, marcapáginas, puzzles, mapas, el número 3 del periódico The Pencil, el reportaje fotográfico, y el vídeo..

La enseñanza de Inglés mediante ordenador.

El proyecto intenta, a partir de un enfoque comunicativo, unir enseñanza de idiomas y tecnología, la segunda como aplicación coherente de las ventajas del ordenador para este tipo de enseñanza. Pretende además, despertar el interés del alumno por el uso del ordenador y desarrollar en él destrezas operativas y manipulativas respecto de éste como instrumento de trabajo. Otro de los objetivos era mejorar las destrezas comunicativas y secuenciar la adquisición de otras destrezas de lecto-escritura acercando el proceso de adquisición de la L2 al de la L1 (lengua materna). A comienzos del curso 93-94 se comenzó la progresiva integración del CALL dentro del programa de Inglés del curso con una dedicación de una o dos horas semanales de las cinco dedicadas al idioma. Se llevó a cabo en la sala de ordenadores del centro a la que acudían en grupos de 22 personas y 2 alumnos por ordenador. Se aplicó a un total de 200 alumnos de quinto, sexto,séptimo, octavo y primero de BUP que ya conocían la metodología desde su incorporación al centro y a otros grupos especiales de preparación de los exámenes Cambridge. Se seleccionaron 11 temas : People, Inventions and Discoveries, Travelling, Ecology, Animals, Sports, Future, Free Time, Cinema, Music and Nature. Los contenidos seleccionados eran de dos tipos: los que proporcionaban los programas adquiridos, en la mayoría de los casos secuenciados por niveles y por temas, y los que el profesor y los alumnos incorporaban con el editor. Una vez elegido el vocabulario que se consideraba que los alumnos debían trabajar en estos niveles educativos, se procedió a la elaboración de los ejercicios donde se incluían los items seleccionados. Para ello se recogieron 6 actividades tipo, relacionadas con la adquisición de vocabulario y con su evaluación. Estos fueron básicamente: definición, palabras que faltan, ordenar una frase, verdad-mentira, elección múltiple, cloze. Se comprobó que la individualización e interacción de alumnos con el ordenador repercute en la eficacia, y el CALL es especialmente efectivo en el caso de la lecto-escritura, y para la adquisición de vocabulario y la transferencia de vocabulario pasivo a activo. Queda demostrado que el CALL es un medio de enseñanza que debe tener un lugar integrado en el conjunto de recursos didácticos del programa. Se utilizaron los programas: Striptext, Time, Numbers and Prepositions, Reading Exercices, Fast Fingers, Coptone Down, Nought and Crosses, Rank Order, Multitester, Dealing with texts, Comparative and Superlative, First Certificate, Which Word, Anagrams, Alphagrame, Mind Word, Word Order, Vocabulary WordStore.

Modelling, control and supervision for a class of hybrid systems

The aim of this thesis is to narrow the gap between two different control techniques: the continuous control and the discrete event control techniques DES. This gap can be reduced by the study of Hybrid systems, and by interpreting as Hybrid systems the majority of large-scale systems. In particular, when looking deeply into a process, it is often possible to identify interaction between discrete and continuous signals. Hybrid systems are systems that have both continuous, and discrete signals. Continuous signals are generally supposed continuous and differentiable in time, since discrete signals are neither continuous nor differentiable in time due to their abrupt changes in time. Continuous signals often represent the measure of natural physical magnitudes such as temperature, pressure etc. The discrete signals are normally artificial signals, operated by human artefacts as current, voltage, light etc. Typical processes modelled as Hybrid systems are production systems, chemical process, or continuos production when time and continuous measures interacts with the transport, and stock inventory system. Complex systems as manufacturing lines are hybrid in a global sense. They can be decomposed into several subsystems, and their links. Another motivation for the study of Hybrid systems is the tools developed by other research domains. These tools benefit from the use of temporal logic for the analysis of several properties of Hybrid systems model, and use it to design systems and controllers, which satisfies physical or imposed restrictions. This thesis is focused in particular types of systems with discrete and continuous signals in interaction. That can be modelled hard non-linealities, such as hysteresis, jumps in the state, limit cycles, etc. and their possible non-deterministic future behaviour expressed by an interpretable model description. The Hybrid systems treated in this work are systems with several discrete states, always less than thirty states (it can arrive to NP hard problem), and continuous dynamics evolving with expression: with Ki ¡ Rn constant vectors or matrices for X components vector. In several states the continuous evolution can be several of them Ki = 0. In this formulation, the mathematics can express Time invariant linear system. By the use of this expression for a local part, the combination of several local linear models is possible to represent non-linear systems. And with the interaction with discrete events of the system the model can compose non-linear Hybrid systems. Especially multistage processes with high continuous dynamics are well represented by the proposed methodology. Sate vectors with more than two components, as third order models or higher is well approximated by the proposed approximation. Flexible belt transmission, chemical reactions with initial start-up and mobile robots with important friction are several physical systems, which profits from the benefits of proposed methodology (accuracy). The motivation of this thesis is to obtain a solution that can control and drive the Hybrid systems from the origin or starting point to the goal. How to obtain this solution, and which is the best solution in terms of one cost function subject to the physical restrictions and control actions is analysed. Hybrid systems that have several possible states, different ways to drive the system to the goal and different continuous control signals are problems that motivate this research. The requirements of the system on which we work is: a model that can represent the behaviour of the non-linear systems, and that possibilities the prediction of possible future behaviour for the model, in order to apply an supervisor which decides the optimal and secure action to drive the system toward the goal. Specific problems can be determined by the use of this kind of hybrid models are: - The unity of order. - Control the system along a reachable path. - Control the system in a safe path. - Optimise the cost function. - Modularity of control The proposed model solves the specified problems in the switching models problem, the initial condition calculus and the unity of the order models. Continuous and discrete phenomena are represented in Linear hybrid models, defined with defined eighth-tuple parameters to model different types of hybrid phenomena. Applying a transformation over the state vector : for LTI system we obtain from a two-dimensional SS a single parameter, alpha, which still maintains the dynamical information. Combining this parameter with the system output, a complete description of the system is obtained in a form of a graph in polar representation. Using Tagaki-Sugeno type III is a fuzzy model which include linear time invariant LTI models for each local model, the fuzzyfication of different LTI local model gives as a result a non-linear time invariant model. In our case the output and the alpha measure govern the membership function. Hybrid systems control is a huge task, the processes need to be guided from the Starting point to the desired End point, passing a through of different specific states and points in the trajectory. The system can be structured in different levels of abstraction and the control in three layers for the Hybrid systems from planning the process to produce the actions, these are the planning, the process and control layer. In this case the algorithms will be applied to robotics ¡V a domain where improvements are well accepted ¡V it is expected to find a simple repetitive processes for which the extra effort in complexity can be compensated by some cost reductions. It may be also interesting to implement some control optimisation to processes such as fuel injection, DC-DC converters etc. In order to apply the RW theory of discrete event systems on a Hybrid system, we must abstract the continuous signals and to project the events generated for these signals, to obtain new sets of observable and controllable events. Ramadge & Wonham¡¦s theory along with the TCT software give a Controllable Sublanguage of the legal language generated for a Discrete Event System (DES). Continuous abstraction transforms predicates over continuous variables into controllable or uncontrollable events, and modifies the set of uncontrollable, controllable observable and unobservable events. Continuous signals produce into the system virtual events, when this crosses the bound limits. If this event is deterministic, they can be projected. It is necessary to determine the controllability of this event, in order to assign this to the corresponding set, , controllable, uncontrollable, observable and unobservable set of events. Find optimal trajectories in order to minimise some cost function is the goal of the modelling procedure. Mathematical model for the system allows the user to apply mathematical techniques over this expression. These possibilities are, to minimise a specific cost function, to obtain optimal controllers and to approximate a specific trajectory. The combination of the Dynamic Programming with Bellman Principle of optimality, give us the procedure to solve the minimum time trajectory for Hybrid systems. The problem is greater when there exists interaction between adjacent states. In Hybrid systems the problem is to determine the partial set points to be applied at the local models. Optimal controller can be implemented in each local model in order to assure the minimisation of the local costs. The solution of this problem needs to give us the trajectory to follow the system. Trajectory marked by a set of set points to force the system to passing over them. Several ways are possible to drive the system from the Starting point Xi to the End point Xf. Different ways are interesting in: dynamic sense, minimum states, approximation at set points, etc. These ways need to be safe and viable and RchW. And only one of them must to be applied, normally the best, which minimises the proposed cost function. A Reachable Way, this means the controllable way and safe, will be evaluated in order to obtain which one minimises the cost function. Contribution of this work is a complete framework to work with the majority Hybrid systems, the procedures to model, control and supervise are defined and explained and its use is demonstrated. Also explained is the procedure to model the systems to be analysed for automatic verification. Great improvements were obtained by using this methodology in comparison to using other piecewise linear approximations. It is demonstrated in particular cases this methodology can provide best approximation. The most important contribution of this work, is the Alpha approximation for non-linear systems with high dynamics While this kind of process is not typical, but in this case the Alpha approximation is the best linear approximation to use, and give a compact representation.

A aprendizagem cooperativa como estratégia promotora de inclusão no 1º Ciclo

Deste Trabalho de projeto faz parte uma intervenção junto de uma turma que inclui um aluno considerado com necessidades educativas especiais. A intervenção ocorreu numa turma do 1º ano de escolaridade, numa escola de uma cidade do Alto Alentejo, onde está o aluno desencadeador da nossa ação, diagnosticado com a Síndrome de Prader-Willi. Considerando que a intervenção necessita de ser fundamentada em pressupostos teóricos que sustentem as opções realizadas, no enquadramento teórico são tratados os temas: inclusão, organização e funcionamento da educação especial, aprendizagem cooperativa e estratégias na sala de aula e por último a síndrome de Prader-willi. Relativamente ao enquadramento metodológico, atendendo ao facto da investigação ser realizada numa turma onde vamos intervir, leva a que se trate de uma investigação em que a componente reflexiva teve um papel decisivo em todas as fases do trabalho, tendo-se optado por uma metodologia qualitativa assente nos princípios da investigação-ação. Utilizámos diversos métodos para a recolha de dados, nomeadamente a análise documental, a observação naturalista, a entrevista e a sociometria, o que nos permitiu recolher várias perspetivas sobre o mesmo contexto e proceder a cruzamentos entre elas. Da caracterização da turma, do aluno e dos contextos, partimos para uma intervenção estruturada, numa dinâmica de planificação, ação, avaliação e reflexão, geradora de práticas educativas diferenciadas e inclusivas. Pretendemos, com a intervenção, criar uma dinâmica cooperativa e de colaboração no grupo da turma, para que se alcance uma situação de inclusão educativa, em que os alunos aprendem todos e com todos, para conseguirem obter sucesso educativo. Os resultados obtidos indicam-nos que o aluno está incluído e que ao longo das sessões de trabalho foi mantendo um nível de interação mais positivo com os colegas. As atividades desenvolvidas tiveram impacto sobre todos os alunos e não apenas sobre o aluno desencadeador da ação.

A mobilidade no sector bancário português

Devido ao período difícil que o país atravessa é importante para todos os sectores empresariais e também, para a banca, que não se percam clientes para a concorrência, de modo a conseguir fidelizá-los. Os consumidores têm o direito de eleger o banco onde pretendem que exista uma relação. Desta forma, perante o mercado existente e os produtos que as instituições bancárias oferecem num determinado momento, os consumidores têm de analisar as várias propostas dos bancos e esta escolha tem por base diversos fatores: o preço, a localização do banco, qualidade de atendimento, etc. No caso de um determinado consumidor não estar satisfeito com o serviço prestado pelo seu banco, quer em termos de preços ou qualidade, tem o direito de mudar de banco. No entanto, e perante a crise que se atravessa, os bancos colocam alguns entraves na saída do cliente para o banco concorrente, nomeadamente, custos de mudança. Estes custos refletem, principalmente, as comissões de encerramento de produtos bancários. Assim, para que a mobilidade dos clientes se realize sem entraves, os bancos devem simplificar as medidas de modo a facilitar este processo de transferência dos clientes, para outras instituições.

Developmental changes in the germinability, desiccation tolerance, hardseededness, and longevity of individual seeds of Trifolium ambiguum

Background and Aims: Using two parental clones of outcrossing Trifolium ambiguum as a potential model system, we examined how during seed development the maternal parent, number of seeds per pod, seed position within the pod, and pod position within the inflorescence influenced individual seed fresh weight, dry weight, water content, germinability, desiccation tolerance, hardseededness, and subsequent longevity of individual seeds. Methods: Near simultaneous, manual reciprocal crosses were carried out between clonal lines for two experiments. Infructescences were harvested at intervals during seed development. Each individual seed was weighed and then used to determine dry weight or one of the physiological behaviour traits. Key Results: Whilst population mass maturity was reached at 33–36 days after pollination (DAP), seed-to-seed variation in maximum seed dry weight, when it was achieved, and when maturation drying commenced, was considerable. Individual seeds acquired germinability between 14 and 44 DAP, desiccation tolerance between 30 and 40 DAP, and the capability to become hardseeded between 30 and 47 DAP. The time for viability to fall to 50 % (p50) at 60 % relative humidity and 45 °C increased between 36 and 56 DAP, when the seed coats of most individuals had become dark orange, but declined thereafter. Individual seed f. wt at harvest did not correlate with air-dry storage survival period. Analysing survival data for cohorts of seeds reduced the standard deviation of the normal distribution of seed deaths in time, but no sub-population showed complete uniformity of survival period. Conclusions: Variation in individual seed behaviours within a developing population is inherent and inevitable. In this outbreeder, there is significant variation in seed longevity which appears dependent on embryo genotype with little effect of maternal genotype or architectural factors.

Unilateral incompatibility in Capsicum (Solanaceae): Occurrence and taxonomic distribution

Background and aims Unilateral incompatibility (UI) occurs when pollinations between species are successful in one direction but not in the other. Self-incompatible (SI) species frequently show UI with genetically related, self-compatible (SC) species, as pollen of SI species is compatible on the SC pistil, but not vice versa. Many examples of unilateral incompatibility, and all those which have been studied most intensively, are found in the Solanaceae, particularly Lycopersicon, Solanum, Nicotiana and Petunia. The genus Capsicum is evolutionarily somewhat distant from Lycopersicon and Solanum and even further removed from Nicotiana and Petunia. Unilateral incompatibility has also been reported in Capsicum; however, this is the first comprehensive study of crosses between all readily available species in the genus. Methods All readily available (wild and domesticated) species in the genus are used as plant material, including the three genera from the Capsicum pubescens complex plus eight other species. Pollinations were made on pot-grown plants in a glasshouse. The number of pistils pollinated per cross varied (from five to 40 pistils per plant), depending on the numbers of flowers available. Pistils were collected 24 h after pollination and fixed for 3-24 h. After staining, pistils were mounted in a drop of stain, squashed gently under a cover slip and examined microscopically under ultra-violet light for pollen tube growth. Key results Unilateral incompatibility is confirmed in the C. pubescens complex. Its direction conforms to that predominant in the Solanaceae and other families, i.e. pistils of self-incompatible species, or self-compatible taxa closely related to self-incompatible species, inhibit pollen tubes of self-compatible species. Conclusions Unilateral incompatibility in Capsicum does not seem to have arisen to prevent introgression of self-compatibility into self-incompatible taxa, but as a by-product of divergence of the C. pubescens complex from the remainder of the genus. (C) 2004 Annals of Botany Company.