[Truncated abstract] There is a well-documented global decline of seagrass meadows in response to anthropogenic pressures. Transplantation of rhizome fragments into denuded areas has been used to enhance natural recovery but nutrient limitation and poor root growth may contribute to low success rates. Addition of nutrients to sediments has been proposed as a means of enhancing growth and survival of seagrass transplants by alleviating nutrient limitation but there is limited information of the effects of nutrient additions to seagrass transplants, particularly root development and morphology. In addition to nutrient limitation, sulphide accumulation in sediments with high organic matter has been shown to reduce seagrass growth and experimental iron additions have been shown to enhance seagrass growth by buffering the development of reduced conditions in organic rich sediments. This thesis examines responses (growth, morphology and nutrient status) of Posidonia australis and Posidonia sinuosa transplants to nitrogen (N), phosphorus (P) and chelated iron (Fe EDTA) additions, and includes a detailed investigation of root growth and morphology in response to these additions. Experiments were carried out in underwater plots in Oyster Harbour, a sheltered estuarine inlet with seasonal river flow, located on the southern coast of Western Australia. In the first experiment, nutrients (N, P and N+P) and Fe EDTA were added to sediment underlying transplants at the end of summer (March 2005). ... Nitrogen (both N and N+P) addition also reduced overall biomass allocation to roots. Nitrogen concentrations increased with N addition in P. sinuosa only but both species had more negative d15N values with N and N+P addition indicating that added N had been taken up. In contrast, P addition had little effect on root growth, and P concentrations only increased in P. australis. However, tissue concentrations of Zn, Co, and Mo in both species increased with P addition. Roots showed limited morphological variation (total root length, mean root diameter, root fineness, specific root length, surface area) in response to nutrient addition. Combined N and P addition increased lateral root density (branches m-1) but had no effect on other morphological parameters of the root compartment. Iron addition had no effect on P. sinuosa but P. australis transplants significantly reduced root growth and productivity, particularly in spring/summer growth period, due to lower primary and lateral growth rates. Overall, N or P additions did not enhance growth although these nutrients were taken up. Iron additions also had little effect on transplant growth. Seagrass transplants had significant root growth although they appeared not to respond to nutrient or iron addition. Both species produced extensive root systems capable of taking up sediment nutrients, which suggests that root development was not a limiting factor in establishment and growth of transplants in the temperate estuary, Oyster Harbour.

La capacité d’une plante à réguler sa croissance racinaire est une composante importante de l’acclimatation aux stress environnementaux. A l’échelle cellulaire, cette régulation est effectuée via le contrôle de la division et de l’élongation des cellules mais les rôles respectifs de chaque processus et leurs interactions sont peu connus. Notamment, l’activité de production de cellules du méristème apical racinaire (RAM) est trop souvent négligée. Dans cette thèse, l’analyse spatiale de la croissance le long de l’apex racinaire et l’analyse temporelle des trajectoires de croissance des cellules ont été couplées pour comprendre les liens existants entre division et élongation cellulaire. Pour cela, j’ai développé un système de phénotypage de la croissance à haute résolution spatio-temporelle qui a été appliqué à l’étude de racines d’un peuplier euraméricain (Populus deltoides × Populus nigra) en réponse à différents stress (stress osmotique, impédance mécanique). Une forte variabilité du taux de croissance racinaire entre individus ainsi que des variations individuelles cycliques de la croissance ont été observées malgré des conditions environnementales contrôlées. L’utilisation de cette variabilité couplée à la quantification de l’activité du RAM a mis en évidence l’importance du taux de production de cellules pour soutenir la croissance racinaire. Ces travaux analysent une nouvelle échelle de variations spatiales et temporelles de la croissance peu prise en compte jusqu’à présent. Hautement applicable à d’autres questions scientifiques, l’analyse du devenir des cellules une fois sortie du RAM est également discutée pour des conditions de croissance non stables / Regulation of root growth is a crucial capacity of plants for acclimatization to environmental stresses. At cell scale, this regulation is controlled through cell division and cell elongation but respective importance of these processes and interactions between them are still poorly known. Notably, the cell production activity of the root apical meristem (RAM) is often excluded. During this thesis, spatial analyses of growth along the root apex were coupled with temporal analyses of cell trajectories in order to decipher the links between cell division and cell elongation. This required the setup of a system for phenotyping root growth at a high spatiotemporal resolution which was applied to study the growth of roots from an euramerican poplar (Populus deltoides × Populus nigra) in response to different environmental stresses (osmotic stress or mechanical impedance). An important variability of root growth rate between individuals as well as individual cyclic variations of growth along time were observed despite tightly controlled environmental conditions. Use of this variability coupled with quantification of the RAM activity led us to a better understanding of the importance of the cell production rate for sustaining root growth. This work analyses a new spatiotemporal scale of growth variability poorly considered. Widely applicable to others scientific questioning, temporal analyses of cell fate once produced in the RAM is also discussed for non-steady growth conditions

The purpose of the master's thesis is to study the morphological adaptation of the root systems of petrophytic family Caryophyllaceae to extreme conditions. The work consisted of two blocks: Laboratory experiment to study the growth of Ni-excluder Silene baschkirorum roots on agar plates with the introduction of Ni, Ca, Mg in different combinations in comparison with the Ni-hyperaccumulator Alyssum obovatum. The structural features of the leaves and the underground sphere of the 6 types of Caryophyllaceae from natural habitats with moisture deficiency. The objects of the study were four perennial main-rooted species: Dianthus versicolor, Gypsophila altissima, Silene baschkirorum, Dianthus acicularis, and two annual species – Spergula arvensis and Arenaria serpyllifolia. The influence of Ni, Ca, Mg in different combinations on the growth of roots of seedlings Alyssum obovatum and Silene baschkirorum was studied in a laboratory experiment on agar plates under standard conditions at a constant temperature and a 16-hour photoperiod in accordance with the Protocol with modifications [Xu et al., 2013]. Morphological parameters of the leaf and underground sphere of Caryophyllaceae were measured by standard morpho-anatomical methods during adaptation to moisture deficiency [Иванова, 2014; Таршис, 2007]. The results of laboratory studies have shown that in all variants of the experiment the root system of Alyssum obovatum was in 1,5–5 times better developed than Silene baschkirorum. The introduction of metals stimulated the growth of the root system in A. obovatum and didn’t affect the growth of S. baschkirorum roots. Analysis of the leaf structure in 6 species of Caryophyllaceae growing in conditions of lack of moisture revealed that xeromesophytes Arenaria serpyllifolia, Dianthus versicolor, Gypsophila altissima have low leaf density both per area and per leaf volume in comparison with mesoxerophytic species Silene baschkirorum, Dianthus acicularis, Spergula arvensis. Analysis of the root system and absorbing roots revealed no differences between studied xeromesophytic and mesoxerophytic Caryophyllaceae species. It’s established that the adaptation of the underground sphere of the studied Caryophyllaceae to the moisture deficit is realized by species-specific ways of restructuring of the root system and absorbing roots. The work consists of 3 chapters, 34 pages, includes 67 sources, 1 table and 7 pictures. The materials of the master's thesis were presented at the all-Russian conference of young scientists «Ecology: facts, hypotheses, models», dedicated to the memory of N. V. Glotov on April 10–13, 2018. In July 2019, it is planned to present the materials of this work in the form of a graphic stand at the international conference IAVS 62nd ANNUAL SYMPOSIUM «Vegetation Science and Biodiversity Research» at the University of Bremen, Germany. / Цель выпускной квалификационной работы магистра заключается в изучении морфологической адаптации корневых систем петрофитных гвоздичных к экстремальным условиям. Работа состояла из двух блоков: Лабораторный эксперимент по изучению роста корней исключителя Ni Silene baschkirorum Janisch. на агаровых пластинах с внесением Ni, Ca, Mg в разных комбинациях в сравнении с гипераккумулятором Ni Alyssum obovatum (C. A. Meyer) Turcz. Описание структурных характеристик листьев и подземной сферы у 6 видов сем. Caryophyllaceae из естественных местообитаний с дефицитом влаги. Объектами исследования послужили четыре многолетних стержнекорневых вида: Dianthus versicolor Fisch. ex Link, Gypsophila altissima L., Silene baschkirorum, Dianthus acicularis Fisch. ex Ledeb., и два однолетних вида – Spergula arvensis L. и Arenaria serpyllifolia L. Влияние Ni, Ca, Mg в разных комбинациях на рост корней проростков Alyssum obovatum и Silene baschkirorum изучали в лабораторном эксперименте на агаровых пластинах в стандартных условиях при постоянной температуре и 16-часовом фотопериоде в соответствии с протоколом с модификациями [Xu et al., 2013]. Морфологические параметры листа и подземной сферы гвоздичных при адаптации к дефициту влаги измеряли с помощью стандартных морфо-анатомических методов [Иванова, 2014; Таршис, 2007]. Результаты лабораторных исследований показали, что во всех вариантах опыта корневая система у Аlyssum obovatum была лучше развита, чем у Silene baschkirorum в 1,55 раз. Внесение металлов стимулировало рост корневой системы у А. obovatum и не влияло на рост корней S. baschkirorum. Анализ структуры листа у 6 видов гвоздичных, произрастающих в условиях недостатка влаги выявил, что ксеромезофиты Arenaria serpyllifolia, Dianthus versicolor, Gypsophila altissima отличаются низкой плотностью листьев как в расчете на площадь, так и на объем листа в сравнении с мезоксерофитными видами Silene baschkirorum, Dianthus acicularis, Spergula arvensis.Анализ корневой системы и поглощающих корней не выявил различий между ксеромезофитными и мезоксерофитными видами изученных гвоздичных (сем. Caryophyllaceae). Установлено, что адаптация подземной сферы изученных гвоздичных к дефициту влаги реализуется видоспецифичными путями перестройки корневой системы и поглощающих корней. Работа состоит из 3 разделов, 34 страниц, включает в себя 67 источников, 1 таблицу и 7 рисунков. Материалы магистерской диссертации были представлены на Всероссийской конференции молодых ученых «Экология: факты, гипотезы, модели», посвященной памяти Н. В. Глотова 1013 апреля 2018 г. В июле 2019 года планируется представить материалы данной работы в форме стенда на международной конференции IAVS 62nd ANNUAL SYMPOSIUM «Vegetation Science and Biodiversity Research» в Бременском университете, Бремен, Германия.

Analyse de la diversité inter et intra-spécifique des paramètres de l’architecture des systèmes racinaires chez les Solanacées. Les racines des plantes jouent un rôle important pour garantir productivité et résistance à de nombreux stress. Dans le nouveau contexte agricole, l’importance de ce système racinaire et de sonarchitecture sont remises au premier plan. Notre étude porte sur la dynamique de l’architecture racinaire des solanacées, qui contient un ensemble d’espèces horticoles importantes pour l’alimentation. Notre travail porte sur 32 génotypes, parmi 3 groupes d’espèces: aubergines, piments et tomates.Dans cette étude, nous proposons tout d’abord une analyse de la diversité inter et intraspécifique de l’architecture racinaire à travers l’évaluation d’un ensemble de traits qui sont aussi les paramètres d’un modèle dynamique de simulation (ArchiSimple : Pagès et al, 2012). Cette première évaluation a été faite en pots, en utilisant un milieu très favorable à la croissance des plantes et à l’enracinement. Nous montrons que les traits racinaires choisis présentent en effet des variations d’origine génétique, généralement plus fortes entre espèces qu’au sein des espèces. Nous avons également observé des corrélations entre certains traits qui révèlent des compromis ou des coordinations dans les processus de développement.Pour aller plus loin dans la signification des traits racinaires choisis et leur stabilité vis‐à‐vis des conditions environnementales, nous avons également évalué ces traits en conditions de culture hydroponique. C’est un milieu reconnu comme radicalement différent, intéressant pour les possibilités de visualisation des racines qu’il offre. Un dispositif avec des rhizotrons hydroponiques a été construit spécifiquement pour cette expérimentation. Nous avons confirmé, dans ces nouvelles conditions, les différences d’origine génétique entre les différents génotypes utilisés. De plus, nous avons comparé de manière systématique les valeurs de traits mesurés avec celles de la précédente expérimentation. Certains traits se révèlent stables ou très corrélés (e.g. diamètres, distances interramification)alors que d’autres présentent des différences beaucoup plus fortes (e.g. vitesses de croissance, vitesses d’émergence des racines adventives).Une troisième expérimentation, utilisant différentes combinaisons de greffage entre génotypes, nous a permis d’approfondir la question du contrôle des traits par des interactions au sein de la plante: soit à courte distance au sein du système racinaire, soit à plus longue distance parle système aérien. Deux traits importants ont été étudiés (le diamètre apical et la densité de ramification) en utilisant des combinaisons de génotypes ayant des valeurs contrastées par rapport à ces traits. Il en ressort des réponses très différentes, avec un effet marqué du greffon sur les111RésuméBui H.H. (2015), Diversité inter- et intra-spécifique des paramètres racinaires chez les Solanacées diamètres, révélant qu’une partie au moins du contrôle de ce trait est effectuée par le système aérien, et un effet faible ou inexistant du greffon sur la densité de ramification, révélant un contrôle local de ce trait, par des interactions à courte distance entre les racines. Cette expérimentation par greffage a montré un potentiel très intéressant pour mettre en lumière divers mécanismes de contrôle des traits au sein de la plante entière.Cette étude mérite d’être prolongée par des analyses plus systématiques des déterminismes de variation des traits de l’architecture racinaire, et par des simulations par modèle qui permettront de synthétiser les conséquences des variations de traits sur les performances globales des systèmes racinaires pour la prospection du sol. / Analysis of the inter and intra specific diversity of the parameters of the root system architecture in the Solanaceae.Plant roots play an important role to ensure the productivity and the resistance to manystresses. In new agricultural context, the importance of root system and its architecture are placed tothe forefront. Our study focuses on the root architecture dynamics of Solanaceae, which contains aseries of important horticultural species for the alimentation. Our work was based on 32 genotypesbelonging to three groups of species: aubergines, capsicums, and tomatoes.In this study, we propose firstly an analysis of inter‐ and intra ‐ specific diversity of rootarchitecture through evaluating a set of traits which are also the parameters of a dynamic simulationmodel (ArchiSimple: Pagès et al, 2012). The experiment in pots with a very favorable condition forplant growth and rooting was conducted for the first evaluation. It showed that the selected roottraits present an effect of genetic ‐ originated variations and this effect is usually stronger amongspecies than within species. We also found correlations between certain traits, which revealcompromises or coordinations in the developmental processes.In order to go deeper into the signification of selected root traits and their stability toenvironmental conditions, we also evaluated these traits in hydroponic culture. This environment isradically different, and interesting for its possibilities to visualize the roots. An experimental setupwith hydroponic rhizotrons was specially built for this experiment. In the new conditions, the genetic‐ originated differences between different genotypes used also were found. In addition, wecompared systematically the traits values with those of the previous experiment. Certain traits arestable or highly correlated (e.g., apical diameter, inter‐branch distance), while others are muchdifferent (e.g., root growth rate, emission rate of adventitious roots).In a third experiment, we used different grafting combinations between genotypes todeepen the question of the control of root traits by interactions within plant: either short distancecontrol within root system or long distance control by aerial system. Two important root traits (apicaldiameter and branching density) have been studied by grafting between genotypes which havecontrasting values on these traits. The different responses appear: a significant effect of scion ondiameters, which indicate that at least of this trait is controlled by shoot system, and a weak effect orno effect of scion on branching density, revealing the local control of this trait, by short distanceinteractions between the roots. This experiment showed a great potential of grafting to highlightvarious control mechanisms of root traits within whole plant.AbstractBui H.H. (2015), Diversité inter- et intra-spécifique des paramètres racinaires chez les Solanacées 113This study deserve to be extended by more systematic analysis of determinisms of variationsof root architecture traits, and by using simulation model which allow to integrate the consequencesof traits variations on global performances of root system for prospecting of soil.

No description available.

This thesis compares the in situ water balance of common annual production systems (wheat, lupin, subclover and serradella) with a grazed perennial system (lucerne) at a site in the Avon Catchment, Western Australia. Using a physically-based water balance approach the value of a plant based solution in redressing the hydrological imbalance that has become a feature of much of the dryland agricultural region of Western Australia is investigated. The effectiveness of lucerne in providing greater available storage for buffering large rainfall events, as compared to the annual systems, is illustrated. Continued transpiration following out-of-season rainfall events maintains a larger available storage capacity. In contrast, the annual systems that are fallow over summer only withdrew a small fraction of water by soil evaporation between rainfall events. Under annual systems, the profile moisture store was sequentially increased to the extent that additional increments of rainfall could potentially contribute to deep drainage. A particular focus of this study has been to investigate the presence of soil constraints to root growth, and to assess how these constraints affect the water balance. A site survey indicated the soil penetration resistance was sufficient to impose a physical constraint to root growth. Published literature on the site shows soil acidity is also at a level imposing chemical constraints to root growth. A root growth model “Rootmodel”, for predicting root growth with and without soil constraints is examined in detail as a method for providing root growth parameters for inclusion into the numerical water balance model, SWIM based on Richard’s equation. Functions developed from “Rootmodel” adequately describe the effect of profile limitations to root growth, such as soil strength, moisture availability and temperature. Recommendations are made for inclusion of a growth suppressing function in “rootmodel” based on the chemical limitation of low pH. The effects of soil acidity on the root growth of several species is investigated experimentally and the resultant root data provided a reference point by which the simplified prediction of root growth built into SWIM could be adjusted using a linear reduction function. A similar linear reduction function is also employed to impose a physical constraint in the form of high penetration resistance.

Das Wurzelwachstum von Winterweizen wurde erfasst und modelliert, um teilflächenspezifisches Boden- und Düngemanagement zu verbessern. Die Variation von Wurzellängendichten im Feld wurde über zwei Vegetationsperioden hinweg an zwei unterschiedlichen Standorten in Ostdeutschland untersucht. Zur Auswertungserleichterung der hohen Anzahl an Wurzelproben, wurde eine halbautomatische Methode zur Bildanalyse von Wurzeln entwickelt. Der Einfluss von Änderungen bezüglich Bodenwasserstatus und Bodendichte bzw. Durchdringungswiderstand auf das Wurzelwachstum wurde untersucht. Die erhobenen Felddaten dienten gleichzeitig dazu, die Bodenwasser- und Wurzelwachstumsberechnung des Modells CERES-Wheat zu validieren. Das Modell simulierte die unterschiedlichen Bodeneigenschaften sowie die Wurzellängendichten und Bodenwassergehalte nur unzureichend. Der Effekt von Änderungen der Niederschlagsmengen auf die Simulationen von Wurzellängendichten und Bodenwassergehalten wurde anhand einer Unsicherheitsanalyse getestet und war extrem gering. Des Weiteren wurde eine Methode für praktische Zwecke entwickelt, mit der die Generierung von räumlich hoch aufgelösten Bodeninformationen unter Verwendung limitierter Eingangsdaten möglich ist. Die Modellkalkulationen basieren auf der Dempster-Shafer-Theorie. Anhand von multitemporal und multimodal erfassten Bodenleitfähigkeitsdaten, die Eingangsdaten für den Modellansatz sind, wurden Bodentypen und Texturklassen bestimmt. Das Modell generiert eine digitale Bodenkarte, die flächenhafte Informationen über Bodentypen und Bodeneigenschaften enthält. Die Validation der Bodenkarte mit zusätzlich erhobenen Bodeninformationen ergab gute bis sehr gute Ergebnisse. / Winter wheat root growth was measured and modelled to improve site-specific soil and fertilizer management in commercial wheat fields. Field variations in root length densities were analysed at two contrasting sites in East-Germany during two vegetation seasons. A semi-automated root analysing method was developed to facilitate analyses of large numbers of samples. Influences of variations in soil water states, bulk densities and penetration resistances on spatial distributions of roots were quantified. Differences in soil characteristics were large between the two sites and affected root growth considerably. The same field data was used for validating the soil moisture and root growth calculations of the widely applied growth model CERES-Wheat. Simulations of root length densities, soil physical properties and soil water contents were inadequate. The effects of changes of rainfall variabilities on simulated root length densities and soil water contents were tested by uncertainty analysis but were negligible low. A methodology for generating soil information for practical management purposes at a high degree of spatial resolution using limited input information was developed. The corresponding model calculations were carried out based on the Dempster and Shafer theorem. Soil types and texture classes were determined with multimodally and multitemporally captured data of soil electrical conductivities which are required input data of the new model approach. The model generates a digital map with extensive information of spatial variations in soil properties. The validation of the generated soil map with soil data from independent measurements yielded close correlation between measured and calculated values.

The nuclear pore complex (NPC) is perhaps the largest protein complex in the eukaryotic cell, and controls the movement of molecules across the nuclear envelope. The NPC is composed of up to 30 proteins termed nucleoporins (Nups), each grouped in different sub-complexes. The transmembrane ring sub-complex is composed of Nups responsible for anchoring the NPC to the nuclear envelope. Bioinformatic analysis has traced all major sub-complexes of the NPC back to the last eukaryotic common ancestor, meaning that the nuclear pore structure and function is conserved amongst all eukaryotes. In this study Arabidopsis T-DNA knockout lines for these genes were investigated to characterise gene function. Differences in plant growth and development were observed for the ndc1 knockout line compared to wild-type but gp210 plants showed no phenotypic differences. The double knockout line gp210 ndc1 was generated through crosses to observe plant response to the knockout of two anchoring-Nup genes. No synergistic affect from this double knockout was observed, suggesting that more, as yet unidentified Nups function the transmembrane ring in plants. The sensitivity to nuclear export inhibitor leptomycin B (LMB) was tested also for knockout lines, although growth sensitivity to the drug was not observed. Nucleocytoplasmic transport of knockout lines was measured in cells transformed by particle bombardment. To express fluorescent protein constructs actively transported through the NPC, localisation of protein determined the nucleocytoplasmic transport of the cell. The ndc1single knockout and the double knockout gp210 ndc1 exhibited decreased nuclear export. Further experiments in determining NDC1 localisation and identification of other Nups in the transmembrane ring sub-complex would bring a more comprehensive understanding to the plant NPC.