Dissertations / Theses on the topic 'Root system strength and architecture'
To see the other types of publications on this topic, follow the link: Root system strength and architecture.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 35 dissertations / theses for your research on the topic 'Root system strength and architecture.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Docker, Benjamin Brougham. "Biotechnical engineering on alluvial riverbanks of southeastern Australia: A quantified model of the earth-reinforcing properties of some native riparian trees." University of Sydney, 2004. http://hdl.handle.net/2123/1688.
Full textAbstract:
Doctor of Philosophy(PhD)It is generally accepted that tree roots can reinforce soil and improve the stability of vegetated slopes. Tree root reinforcement is also recognised in riverbanks although the contribution that the roots make to bank stability has rarely been assessed due to the reluctance of geomorphologists to examine riverbank stability by geomechanical methods that allow for the inclusion of quantified biotechnical parameters. This study investigates the interaction between alluvial soil and the roots of four southeastern Australian riparian trees. It quantifies the amount and distribution of root reinforcement present beneath typically vegetated riverbanks of the upper Nepean River, New South Wales, and examines the effect of the reinforcement on the stability of these banks. The ability of a tree to reinforce the soil is limited by the spatial distribution of its root system and the strength that the roots impart to the soil during shear. These two parameters were determined for the following four species of native riparian tree: Casuarina glauca, Eucalyptus amplifolia, Eucalyptus elata, and Acacia floribunda. The four species all exhibit a progressive reduction in the quantity of root material both with increasing depth and with increasing lateral distance from the tree stem. In the vertical direction there are two distinct zones that can be described. The first occurs from between 0 and approximately 15 % of the maximum vertical depth and consists of approximately 80 % of the total root material quantity. In this zone the root system consists of both vertical and lateral roots, the size and density of which varies between species. The second zone occurs below approximately 15 % of the maximum vertical depth and consists primarily of vertical roots. The quantity of root material in this zone decreases exponentially with depth due to the taper of individual roots. The earth reinforcement potential in terms of both geometric extent and the quantity of root material expressed as the Root Area Ratio (RAR) varies significantly from species to species. E. elata exhibited the highest values of RAR in soil zones beneath it while E. amplifolia reinforced a greater volume of soil than any of the other species examined. The increased shear resistance (Sr) of alluvial soil containing roots was measured by direct in-situ shear tests on soil blocks beneath a plantation. For three of the species (C. glauca, E. amplifolia, E. elata) Sr increased with increasing RAR measured at the shear plane, in a similar linear relationship. The shear resistance provided by A. floribunda roots also increased with increasing RAR at the shear plane but at a much greater rate than for the other three species. This is attributable to A. floribunda’s greater root tensile strength and therefore pull-out resistance, as well as its smaller root diameters at comparative RARs which resulted in a greater proportion of roots reaching full tensile strength within the confines of the test. Tree roots fail progressively in this system. Therefore determining the increased shear strength from the sum of the pull-out or tensile strengths of all individual roots and Waldron’s (1977) and Wu et al’s (1979) simple root model, would result in substantial over estimates of the overall strength of the soil-root system. The average difference between Sr calculated in this manner and that measured from direct in-situ shear tests is 10.9 kPa for C. glauca, 19.0 kPa for E. amplifolia, 19.3 kPa for E. elata, and 8.8 kPa for A. floribunda. A riverbank stability analysis incorporating the root reinforcement effect was conducted using a predictive model of the spatial distribution of root reinforcement beneath riparian trees within the study area. The model is based on measurements of juveniles and observations of the rooting habits of mature trees. It indicates that while the presence of vegetation on riverbank profiles has the potential to increase stability by up to 105 %, the relative increase depends heavily on the actual vegetation type, density, and location on the bank profile. Of the species examined in this study the greatest potential for improved riverbank stability is provided by E. amplifolia, followed by E. elata, A. floribunda, and C. glauca. The presence of trees on banks of the Nepean River has the potential to raise the critical factor of safety (FoS) from a value that is very unstable (0.85) to significantly above 1.00 even when the banks are completely saturated and subject to rapid draw-down. It is likely then that the period of intense bank instability observed within this environment between 1947 and 1992 would not have taken place had the riparian vegetation not been cleared prior to the onset of wetter climatic conditions. Typical ‘present-day’ profiles are critically to marginally stable. The introduction of vegetation could improve stability by raising the FoS up to 1.68 however the selection of revegetation species is crucial. With the placement of a large growing Eucalypt at a suitable spacing (around 3-5 m) the choice of smaller understorey trees and shrubs is less important. The effect of riparian vegetation on bank stability has important implications for channel morphological change. This study quantifies the mechanical earth reinforcing effect of some native riparian trees, thus allowing for improved deterministic assessment of historical channel change and an improved basis for future riverine management.
2
Kellermeier, Fabian. "Environmental genetics of root system architecture." Thesis, University of Glasgow, 2013. http://theses.gla.ac.uk/4663/.
Full textAbstract:
The root system is the plant’s principal organ for water and mineral nutrient supply. Root growth follows an endogenous, developmental programme. Yet, this programme can be modulated by external cues which makes root system architecture (RSA), the spatial configuration of all root parts, a highly plastic trait. Presence or absence of nutrients such as nitrate (N), phosphate (P), potassium (K) and sulphate (S) serve as environmental signals to which a plant responds with targeted proliferation or restriction of main or lateral root growth. In turn, RSA serves as a quantitative reporter system of nutrient starvation responses and can therefore be used to study nutrient sensing and signalling mechanisms. In this study, I have analysed root architectural responses of various Arabidopsis thaliana genotypes (wildtype, mutants and natural accessions) to single and multiple nutrient deficiency treatments. A comprehensive analysis of combinatorial N, P, K an S supply allowed me to dissect the effect of individual nutrients on individual root parameters. It also highlighted the existence of interactive effects arising from simultaneous environmental stimuli. Quantification of appropriate RSA parameters allowed for targeted testing of known regulatory genes in specific nutritional settings. This revealed, for example, a novel role for CIPK23, AKT1 and NRT1.1 in integrating K and N effects on higher order lateral root branching and main root angle. A significant contribution to phenotypic variation also arose from P*K interactions. I could show that the iron (Fe) concentration in the external medium is an important driving force of RSA responses to low-P and low-K. In fact, P and K deprivation caused Fe accumulation in distinct parts of the root system, as demonstrated by Fe staining and synchrotron X-Ray fluorescence. Again, selected K, P and Fe transport and signalling mutants were tested for aberrant low-K and/or low-P phenotypes. Most notably, the two paralogous ER-localised multicopper oxidases LPR1 and LPR2 emerged as important signalling components of P and K deprivation, potentially integrating Fe homeostasis with meristematic activity under these conditions. In addition to the targeted characterisation of specific genotype-environment interactions, I investigated novel RSA responses to low-K via a non-targeted approach based on natural variation. A morphological gradient spanned the entire genotype set, linking two extreme strategies of low-K responses. Strategy I accessions responded to low-K with a moderate reduction of main root growth but a severe restriction of lateral root elongation. In contrast, strategy II genotypes ceded main root growth in favour of lateral root proliferation. The genetic basis of these low-K responses was then subsequently mapped onto the A. thaliana genome via quantitative trait loci (QTL) analysis using recombinant inbred lines derived from parental accessions that either adopt strategy I (Col-0) or II (Ct-1). In sum, this study addresses the question how plants incorporate environmental signals to modulate developmental programmes that underly RSA formation. I present evidence for novel phenotypic responses to nutrient deprivation and for novel genetic regulators involved in nutrient signalling and crosstalk.
3
Johnson, James. "Quantitative analysis of plant root system architecture." Thesis, University of Nottingham, 2018. http://eprints.nottingham.ac.uk/55601/.
Full textAbstract:
The root system of a plant is responsible for supplying it with essential nutrients. The plant's ability to explore the surrounding soil is largely determined by its root system architecture (RSA), which varies with both genetic and environmental conditions. X-ray micro computed tomography (µCT) is a powerful tool allowing the non-invasive study of the root system architecture of plants grown in natural soil environments, providing both 3D descriptions of root architecture and the ability to make multiple measurements over a period of time. Once volumetric µCT data is acquired, the root system must first be segmented from the surrounding soil environment and then described. Automated and semi-automated software tools can be used to extract roots from µCT images, but current methods for the recovery of RSA traits from the resulting volumetric descriptions are somewhat limited. This thesis presents a novel tool (RooTh) which, given a segmented µCT image, skeletonises the root system and quantifies global and local root traits with minimal user interaction. The computationally inexpensive method used takes advantage of curve-fitting and active contours to find the optimal skeleton and thus evaluate root traits objectively. A small-scale experiment was conducted to validate and compare root traits extracted using the method presented here alongside other 2D imaging tools. The results show a good degree of correlation between the two methods.
4
Linkohr, Birgit Isabel. "The control of root system architecture in 'Arabidopsis'." Thesis, University of York, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.428452.
Full text
5
Ribrioux, Sebastien. "Phosphate control of root system architecture in Arabidopsis." Thesis, University of York, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.247735.
Full text
6
Stokes, Alexia. "Responses of young trees to wind : effects on root architecture and anchorage strength." Thesis, University of York, 1994. http://etheses.whiterose.ac.uk/2438/.
Full text
7
佑脩, 田和, and Yusuke Tawa. "Dynamics and architecture of fine root system in a Cryptomeria japonica plantation." Thesis, https://doors.doshisha.ac.jp/opac/opac_link/bibid/BB13106238/?lang=0, 2019. https://doors.doshisha.ac.jp/opac/opac_link/bibid/BB13106238/?lang=0.
Full text
8
Tracy, Saoirse Rosanna. "The response of root system architecture to soil compaction." Thesis, University of Nottingham, 2013. http://eprints.nottingham.ac.uk/13037/.
Full textAbstract:
Soil compaction has been described as the most serious environmental problem caused by conventional agriculture, as it results in several stresses which may interact simultaneously, including increased soil strength, decreased aeration and reduced hydraulic conductivity. Root system architecture (RSA) is the arrangement of roots within the soil matrix and is important because the specific deployment of roots within the soil can determine soil exploration and resource uptake. As roots deliver water and nutrients to growing plants, whilst also providing anchorage, their importance cannot be overstated. Yet, our understanding of how roots interact with the surrounding soil, especially at the micro-scale level, remains limited because soil is an opaque medium, so preventing roots from being visualised without disturbing them. Destructive techniques are commonly employed for the analysis of RSA, however this can result in the loss of key information concerning root architecture, such as elongation rates and root angles and important soil characteristics such as soil structure and pore connectivity. However, X-ray Computed Tomography (CT) has been shown to be a promising technique for visualising RSA in an undisturbed manner. The species considered in this thesis were wheat (Triticum aestivum L.) and tomato (Solanum lycopersicum L.). Further information regarding the response of roots to soil compaction has been achieved through the use of X-ray CT, automatic root tracing software and novel image analysis procedures. Soil compaction significantly affected root length, volume, surface area, angle, diameter, elongation rates and root path tortuosity, however the influence of soil texture on root responses to soil compaction was significant. Moderate compaction benefits root growth in clay soil, possibly due to the greater nutrient and water holding capacity, but adversely affected root growth in loamy sand. The results suggest that there is an optimum level of soil compaction for the different soil types. Roots elongated rapidly between 2-3 days after germination (DAG), it is hypothesised that is related to the mobilization of seed storage substances to the growing roots. The use of transgenic mutants of tomato with altered levels of abscisic acid (ABA) has provided a greater insight into the role of ABA in mediating root responses to soil compaction. This work will enable better phenotyping of plant varieties with enhanced root system traits for resource foraging and uptake. Knowledge of the responses of root systems in heterogeneous soil is vital to validate root phenotypes and overcome future food security challenges.
9
Adu, Michael Osei. "Variations in root system architecture and root growth dynamics of Brassica rapa genotypes using a new scanner-based phenotyping system." Thesis, University of Nottingham, 2014. http://eprints.nottingham.ac.uk/14259/.
Full textAbstract:
There is a need to breed for root systems architectures (RSAs) that optimise soil resource acquisition. This requires high resolution and high-throughput quantification of RSA in as natural an environment as possible. Current imaging techniques are limited by cost, reproducibility, throughput and complexity. This thesis describes (1) the construction of a low cost, high-resolution, root phenotyping platform that requires no sophisticated equipment which is adaptable to most laboratory and glasshouse environments and (2) its application to quantify environmental and temporal variation in RSA between genotypes of Brassica rapa L. The high resolution root phenotyping system (HRP) that was constructed employed 24 scanners and could screen up to 72 individual plants at any time, with the possibility of capturing thousands of root images daily depending on the operational number of scanners and scanning periodicity. Plants were supplied with a complete nutrient solution through the wick of a germination paper. Images of RSA were acquired automatically, over extended periods, using multiple scanners controlled by customised software. The RSA data was used to validate a mechanistic model and mixed effects models were used to describe the sources of variation in traits contributing to RSA. Plants were also grown in rhizoboxes and under varying concentrations of P ([P]ext). Broad-sense heritability (H2), was highest (≥ 0.70) for shoot biomass, length of primary roots (PRs), number of lateral roots (LRs). Coefficients of variation in RSA traits within a genotype were large and ranged between 5 and 103%. It was found that between 4 and 48 replicates were needed to detect a significant difference (95% CI, 50% difference between trait means). Significant differences were found between genotypes in root traits with strong positive correlations among RSA traits and between biomass and RSA traits. Principal component analyses identified 5 significant axes of variation, accounting for approximately 86 and 78% of the variation in the genotypes on paper and soil substrates, respectively. Cluster analysis of the genotypes produced 5 discrete groups. Genotypes with more or less shoot biomass or with bigger or smaller RSA could be distinguished. A density-based 2D model reproduced experimental results accurately by simulating PR length and total length of LRs. Mixed-effects statistical models demonstrated that root traits show temporal variations of various types with significant effects of genotype. All genotypes followed a similar growth pattern with time, but differed in their maximum total root length (TRL), primary root length (PRL) and LR growth. A 3-parameter logistic model satisfactorily described TRL and PRL when genotypes were grown on both paper and soil substrates. On paper substrate, TRL required only a single, random-effect parameter (asymptote), describing maximum TRL. On soil substrate, TRL required two random-effects parameters, asymptote and inflection, describing maximum TRL and time at which ½ of maximum TRL occurs, respectively. Primary root length on both paper and soil substrates required only a single, random-effect parameter, describing maximum PRL. The growth rate of LRs of all ages followed a quadratic function and required only a single, random-effect parameter, describing maximum growth rate. There was variation in specific RSA traits and plasticity in response to [P]ext among genotypes. Length of the apical un-branched zone of the PR increased with increasing [P]ext. Total root length, total LR length and number of LRs was positively correlated with total plant tissue P concentration at low [P]ext but not at high [P]ext. Paper substrate was more suitable for screening seedling root traits but root phenotypes must be validated in situ in the field or in soil media because some differences were evident between data observed on paper and soil substrates. Scanner-based phenotyping of RSA provides economical means of studying the mechanisms underlying the plant-soil interactions and can be used to quantify environmental and temporal variation in traits contributing to RSA. The HRP system can be extended to screen the large populations required for breeding for efficient resource acquisition. The necessity for high replication and time-consuming image analysis could however limit throughput in the phenotyping system.
10
Mairhofer, Stefan. "Extracting root system architecture from X-ray micro computed tomography images using visual tracking." Thesis, University of Nottingham, 2014. http://eprints.nottingham.ac.uk/27739/.
Full textAbstract:
X-ray micro computed tomography (µCT) is increasingly applied in plant biology as an imaging system that is valuable for the study of root development in soil, since it allows the three-dimensional and non-destructive visualisation of plant root systems. Variations in the X-ray attenuation values of root material and the overlap in measured intensity values between roots and soil caused by water and organic matter represent major challenges to the extraction of root system architecture. We propose a novel technique to recover root system information from X-ray CT data, using a strategy based on a visual tracking framework embedding a modiffed level set method that is evolved using the Jensen-Shannon divergence. The model-guided search arising from the visual tracking approach makes the method less sensitive to the natural ambiguity of X-ray attenuation values in the image data and thus allows a better extraction of the root system. The method is extended by mechanisms that account for plagiatropic response in roots as well as collision between root objects originating from different plants that are grown and interact within the same soil environment. Experimental results on monocot and dicot plants, grown in different soil textural types, show the ability of successfully extracting root system information. Various global root system traits are measured from the extracted data and compared to results obtained with alternative methods.
11
Koebernick, Nicolai [Verfasser], Doris [Akademischer Betreuer] Vetterlein, Andrea [Akademischer Betreuer] Carminati, and Andrea [Akademischer Betreuer] Schnepf. "Root water uptake : exploring the role of root system architecture and root-soil interactions with X-ray computed tomography / Nicolai Koebernick ; Doris Vetterlein, Andrea Carminati, Andrea Schnepf." Halle, 2015. http://d-nb.info/1116953978/34.
Full text
12
Zappala, Susan Christine. "The influence of OsAUX1 on root system architecture and phosphorus uptake in rice (Oryza sativa)." Thesis, University of Nottingham, 2014. http://eprints.nottingham.ac.uk/38793/.
Full textAbstract:
Rice (Oryza sativa L.) provides up to 50% of the total calories consumed in countries such as India, Madagascar and Nigeria. As a crop, rice can require significant fertiliser inputs to maintain the required yields. Additionally, climate change has increased the need for rice varieties with improved drought resistance, tolerance to pests and more efficient acquisition of nutrients from soil. One major fertiliser input for rice is phosphate; reducing phosphorus (P) fertiliser use would have environmental and economic implications. Root traits linked to P acquisition in crops include shallow root angle, lateral root proliferation and increases in root hair length and density. Two T-DNA knockout alleles with reduced gravitropic response, Osaux1-1 and Osaux1-2, were used to investigate the influence of shallow root angle on P uptake. OsAUX1 is a rice ortholog for the Arabidopsis thaliana gene AUX1, which controls lateral root growth and gravitropic response. The wildtype and mutant rice plants were grown in soil and non-destructively imaged using X-ray micro Computed Tomography (X-ray CT). In Chapter Three, visualisation of rice roots in soil using X-ray CT was optimised by determining the ideal soil moisture content that would produce the best images. Water in soils has a similar X- ray attenuation density to that of plant roots and can influence segmentation of roots from soil in X-ray CT images. It was found that soil at nominal field capacity (ca. 3 days of drainage) produced the best contrast between soil fractions (organic matter, minerals and pore space) and root material. In Chapter Four, the impact of X-ray dose on root growth was quantified because the experimental design included repeated scanning of the same sample (Chapter Five). It was found that even under repeated scanning, the X-ray doses involved in this work (ca. 15 Gy per sample) did not significantly affect the root architecture and overall plant growth in rice cultivars used. In Chapter Five, Osaux1-1 and Osaux1-2 retained the agravitropic phenotype that was observed on agar-based systems when plants were grown in loamy sand soil. However, when subject to various soil P concentrations and distributions (Chapter Six), Osaux1-1 had similar gravitropic response and P uptake as wildtype. It was unclear what role gravitropism and topsoil foraging played in P uptake for these rice cultivars, if any. OsAUX1 could be linked to P uptake as well as responses to soil P concentration and distribution. Under uniformly low soil P wildtype had a shallower root system distribution than Osaux1-1. Of most interest were the results when sufficient soil P was sequestered to the top 4 cm of the soil column and low P was maintained in the bottom 6 cm. Under these conditions, wildtype took up more overall P, had almost twice the biomass, twice the total root length and twice the surface area when compared to Osaux1-1. This provides evidence that OsAUX1 can be linked to adaptation to P stress and distribution of P in soil through control of fine root characteristics and not necessarily its impact on gravitropic response. Chapter Seven describes the investigation into the impact of OsAUX1 on sub-architectural effects of the root system that could influence P uptake. It was determined that OsAUX1 was involved in root hair density and elongation under varying P availability for agar grown plants. In comparison to wildtype, Osaux1-1 had significant variation in root hair phenotype that seemed unrelated to a P stress response. In flooded environments, root hairs influence the potential for root:soil contact that is integral to P uptake in rice paddies which have reduced soil conditions and mass water flow that can transport plant available soluble P. This reinforces the potential for an interaction between OsAUX1 and P uptake in paddy rice.
13
Arif, Uz Zaman Muhammad. "Delineating Root System Architecture in Rapeseed/Canola (Brassica napus L.) through Molecular and Transcriptomic Approaches." Diss., North Dakota State University, 2018. https://hdl.handle.net/10365/29308.
Full textAbstract:
Root system architecture of plant plays a key role in water and nutrient uptake from the soil, provides anchorage and acts as a storage organ. In this current research, we have focused on the molecular and physiological basis of root system variation in canola (Brassica napus L.). Genome wide association mappings in a diverse canola germplasm panel with ~37,500 and ~30,200 single nucleotide polymorphism (SNP) markers were conducted under greenhouse and field conditions, respectively. A total of 52 significant SNP markers associated with different root architectural traits were identified in the greenhouse study. Majority of the markers were distributed on five chromosomes, A01, A02, A04, C03 and C06, of B. napus. Twenty-two candidate genes related to root growth and development were detected within 50 kbp upstream and downstream of the significant markers. Three of these candidate genes, P-glycoprotein 6 (PGP6), Tetraspanin 7 (TET7) and ARABIDILLO-2, were co-localized with three markers on chromosome C03, A01 and A04, respectively. In the field study, 31 significant SNP markers associated with different root traits were detected. A total of 15 root related candidate genes were identified within 100 kbp upstream and downstream of different significant markers. We also analyzed and compared the transcriptomes from the root systems of spring (weak root system) and winter (vigorous root system) growth habits at two different time points, 30 and 60 days. A total of 169,646 transcripts were analyzed, of which, 582 and 555 transcripts were found to be significantly differentially expressed between spring and winter types at 30 and 60 days, respectively. Several cytokinin and gibberellin associated genes and genes sets were found to be upregulated in spring type compared to winter type at 60 days. Cytokinin has proven inhibitory effect on root system architecture in different crops, whereas, gibberellin promote root elongation but inhibit lateral root growth. Therefore, we suggest that cytokinin and gibberellin may play an important role in root system variation between spring and winter growth habits. Significant marker loci, candidate genes and transcriptome profile identified in this research will assist future research to understand the root system variation in rapeseed/canola.North Dakota State University. Center of Excellence for Agbiotechnology
National institute of Food and Agriculture (U.S.)
Northern Canola Growers Association
14
Dinis, Cati Oliveira. "Cork oak (Quercus suber L.) root system: a structural-functional 3D approach." Doctoral thesis, Universidade de Évora, 2014. http://hdl.handle.net/10174/14573.
Full textAbstract:
The last decades have witnessed the decline and sudden death of the cork oak (Quercus suber L.) in Montado. The complexity of this production system management has lead to a large set of solutions which have been absent by scientific based research findings (such as those related with the cork oak root system) deriving mainly from empirical knowledge application. The present integrated research approach permits a better understanding of the production system vulnerabilities that can result in management modification proposals which will be useful in a near future. To contribute to a more realistic and integrated forest management and planning, a study relying on a morphological evaluation of cork oak root system in a Cambissoil soil, using a 3D digitizing method was performed. Cork oak showed a dimorphic root system with a relative high quantity of sinkers distributed all over the soil profile, one root subsystem at a superficial level until 40 cm depth and another at a deeper level, around 1.20 m depth. Tree biomass allocation was similarly distributed between aerial and root systems. Previously, a study on methodologies for roots excavation - profile washing with water and excavation through high pressure air jet – was carried out. Results showed that for sandy soils the most suitable method is the excavation by high pressure air jet. Both methods showed to be inadequate for clayed soils. Following the evidence that soil compaction could be an important factor for root growth, a study was conducted, in a greenhouse, with cork oak seedlings. Results showed that tap root length and total root biomass (coarse and fine roots) are negatively affected by soil compaction in depth. In regard to the low survival rate of cork oaks regeneration that has been observed in Montado, another complementary study was conducted in a greenhouse where fertilisation, inoculation with mycorrhizal fungi and aminoacids supply were tested. It was concluded that seedlings subjected to fertilisation and inoculation had a more equilibrated growth between shoot and root components. It is expected that the research developed in the present thesis can provide an essential tool for future forest planning and management and for the natural and artificial regeneration processes in cork oak stands, ensuring the maintenance of the typical Montado landscape; Sistema Radical do Sobreiro (Quercus suber L.): Uma Abordagem Estrutural Funcional 3D
Resumo:
Desde as últimas décadas que se tem vindo a testemunhar o declínio e a morte súbita do sobreiro (Quercus suber L.) no Montado. A complexidade da gestão deste sistema de produção engloba um grande conjunto de soluções que, por terem sido ausentes de validação científica (tal como a relacionada com o sistema radical do sobreiro), tem vindo a ser suportado, principalmente, pela aplicação do conhecimento empírico. A presente abordagem integrada permite uma melhor compreensão das vulnerabilidades deste sistema que pode resultar em propostas de alteração de gestão que serão úteis num futuro próximo. De forma a contribuir para uma gestão e planeamento florestal mais realistas e integrados, foi realizado um estudo acerca da avaliação morfológica do sistema radical do sobreiro num cambissolo, usando o método de digitalização 3D. O sobreiro mostrou um sistema radicular dimórfico com uma elevada quantidade relativa de sinkers distribuídos por todo o perfil do solo. Foi observado um subsistema à superfície, até aos 40 cm de profundidade e outro mais profundo, a cerca de 1.20 m. Observou-se também que a biomassa da árvore foi distribuída de forma similar entre os sistemas aéreo e radical. Anteriormente foi conduzido um estudo sobre as metodologias de escavação de raízes - lavagem de perfil com água e escavação por meio de jato de ar de alta pressão. Os resultados mostraram que para solos arenosos, o método mais adequado é o método por meio de jato de ar de alta pressão e, que ambos os métodos mostraram ser inadequados para os solos argilosos. Após a observação de que a compactação do solo pode ser um fator importante para o crescimento das raízes, um estudo foi realizado em ambiente de estufa com plântulas de sobreiro. Os resultados mostraram que o comprimento da raiz principal e a biomassa total de raízes (raízes grossas e finas) foram negativamente afetados pela compactação do solo em profundidade. No que diz respeito à baixa taxa de sobrevivência da regeneração dos sobreiros, outro estudo complementar foi realizado em ambiente de estufa onde a fertilização, a inoculação com fungos micorrizos e o suplemento de aminoácidos foram testados. Concluiu-se que as plântulas submetidas à fertilização e inoculação tiveram um crescimento mais equilibrado entre as componentes aéreas e radicais. Espera-se que a investigação apresentada nesta tese possa proporcionar uma ferramenta essencial para o planeamento e gestão florestal futuros e, contribuir para o sucesso da regeneração natural e artificial dos povoamentos de sobreiro, garantindo a manutenção da paisagem típica do Montado.
15
West, Cortney. "Improving Building Energy Efficiency Through Implementation Of An Active Indoor Rhizospheric Microbe Air Processing System." Thesis, The University of Arizona, 2016. http://hdl.handle.net/10150/612559.
Full textAbstract:
Commercial energy use in Arizona is different from the rest of the United States because of their high demand for air conditioning. Nearly half of the energy used in commercial buildings goes to heating, cooling, and ventilation. In an attempt to reduce overall every use in buildings, looking at these categories led to an examination of ventilation in buildings, which is the main cause for high heating and cooling costs. Ventilation of fresh air is required in order to provide a safe, healthy environment, with acceptable indoor air quality. Indoor air quality and pollution has continuously come to light as a major health concern for building occupants. Chemicals used in manufacturing allow consumers to buy and expose themselves to toxic substances such as volatile organic compounds on a daily basis. With minimal regulations on indoor air, it is important to find ways to better filter and clean it. The traditional solution is ventilation, but more fresh air ventilation means more heating and cooling. This paper explores the research that has been done on plants and phytoremediation and the applicability to indoor air quality. With the proof that certain combinations and amounts of plants can filter the air of volatile organic compounds, systems are explored for indoor air filtration instead of mechanical ventilation. This type of system can greatly reduce heating and cooling costs in buildings due to the reduction of outdoor air being brought in and requiring conditioning. A system of this type is a feasible solution to indoor air quality and can lead to a significant reduction in energy use. The proposed AIRMAPS is a system that in certain quantities can reduce the need for fresh air ventilation by 25%, which in turn has shown through the validation by eQUEST, that the energy used for heating, cooling, and ventilation fans can also be reduced by approximately the same amount. The plants used are spider plant, dumb cane, English ivy, and golden pothos. The average formaldehyde removal by each of these plants is a low approximation of 75% per cubic meter. This paper also considers the growing materials used for the plants; activated carbon, potting soil mix, and grow-stones, as well as their formaldehyde removal capabilities.
16
Kichah, Emmanuelle. "Architecture racinaire des espèces herbacées : diversité de mise en place et plasticité." Thesis, Avignon, 2016. http://www.theses.fr/2016AVIG0675.
Full textAbstract:
Dans de nombreux projets de végétalisation, le sol est la principale entrave à l’implantation des végétaux. Il est donc fondamental de connaitre la manière dont les systèmes racinaires se mettent en place dans le sol. La mise en place du système racinaire dans le milieu souterrain correspond à l’expression du patrimoine génétique guidé par les contraintes du sol. A travers ce document nous avons tout d’abord présenté la mise en place des systèmes racinaires des espèces herbacées résultant du patrimoine génétique puis nous avons présenté sa plasticité face à certaines contraintes du sol. Les espèces ne possèdent pas forcément un simple système racinaire mais une combinaison de systèmes racinaires qui se met progressivement en place. Nous présentons dans ce document une typologie et une classification de ces systèmes racinaires selon leur localisation et l’implication de l’organe-support dans la multiplication de l’espèce. Nous nous intéressons aussi à l’effet des contraintes du sol sur la mise en place de l’architecture racinaire : la résistance à la pénétration qui est une contrainte récurrente même dans les terres cultivées et la porosité grossière qui est une contrainte présente dans les sols remaniés. Des expérimentations ont été menées sur une diversité d’espèces herbacées afin de comparer leur architecture racinaire en présence ou non une zone de contrainte. Concernant la résistance à la pénétration, nous retrouvons et généralisons les résultats obtenus par d’autres chercheurs sur d’autres espèces herbacées tels que la diminution du taux de croissance ou l’augmentation du diamètre des racines au niveau de la contrainte. De même, nous retrouvons des traits prédictifs de capacité de pénétration tels que le diamètre apical racinaire et le taux de croissance racinaire et nous mettons en avant la teneur en matière sèche du système racinaire avec une corrélation négative. Concernant la porosité grossière, nous observons un effet sur la croissance racinaire, le diamètre apical racinaire et le développement de primordia lorsque la porosité est très grossièreIn many revegetation projects, the soil is the main obstacle to the establishment of plants. It is therefore essential to know how the root systems are set up in the ground. The root systems establishment is the expression of the genetic heritage guided by the constraints of the environment. In this document we first presented the root systems development of herbaceous species resulting from genetic and then we presented its plasticity face to soil constraints. The species do not have a single root system, but a combination of root systems that are implemented gradually. We present here a typology and classification of root systems depending on their location and on the bearing-organ involvement in the vegetative multiplication of the species. We are also interested in the effect of soil constraints on the development of root architecture: the penetration resistance is a recurring stress even in cultivated land and the gross porosity is a stress present in soils reworked. Experiments were conducted on a variety of herbaceous species to compare their root architecture with or without a stress zone. Regarding the penetration resistance, we find and generalize the results obtained by other researchers on other herbaceous species such as the decreasing root growth rate or the increasing root diameter at the level of the stress. Similarly, we find the traits predicting the penetration such as root apical diameter and root growth rates and we highlight the root dry matter content with a negative correlation. Regarding the gross porosity, we observe an effect on root growth rate, root apical diameter and primordia development when the porosity is very gross
17
Eysholdt-Derzsó, Emese [Verfasser], Margret [Akademischer Betreuer] Sauter, and Dietrich [Gutachter] Ober. "Ethylene Response Factor VII transcription factors control the reshaping of the root system architecture in response to hypoxia / Emese Eysholdt-Derzsó ; Gutachter: Dietrich Ober ; Betreuer: Margret Sauter." Kiel : Universitätsbibliothek Kiel, 2018. http://d-nb.info/1236287878/34.
Full text
18
Frisell, Marcus. "Information visualization of microservice architecture relations and system monitoring : A case study on the microservices of a digital rights management company - an observability perspective." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-233463.
Full textAbstract:
90% of the data that exists today has been created over the last two years only. Part of the data space is created and collected by machines, sending logs of internal measurements to be analyzed and used to evaluate service incidents. However, efficiently comprehending datasets requires more than just access to data, as Richard Hamming puts it; "The purpose of computing is insight, not numbers." A tool to simplify apprehension of complex datasets is information visualization, which works by transforming layers of information into a visual medium, enabling the human perception to quickly extract valuable information and recognise patterns. This was an experimental design-oriented research study, set out to explore if an information visualization of microservice architecture relations combined with system health data could help developers at a Swedish digital rights management company (DRMC) to find root cause incidents, increase observability and decision support, i.e. simplifying the incident handling process. To explore this, a prototype was developed and user tests consisting of a set of tasks as well as a semi-structured interview was executed by ten developers at DRMC. The results concluded that the proposed solution provided a welcomed overview of service health and dependencies but that it lacked the ability to effectively focus on certain services, essentially making it difficult to find root causes. Visualizations like this seems to be best suited for overview-, rather than focused, comprehension. Further research could be conducted on how to efficiently render large complex datasets while maintaining focus and how to account for external factors.90% av alla data som finns idag har skapats under de senaste två åren. En del av datautrymmet skapas och samlas in av maskiner som genererar loggar innehållandes interna systemmätningar för att utvärdera felaktiga tjänster. För att effektivt förstå ett dataset krävs mer än bara tillgång till data, som Rickard Hamming har sagt; “Syftet med datoranvändning är insikt, inte siffror.” Ett verktyg för att förenkla ens uppfattning av komplexa dataset är informationsvisualisering. Det fungerar genom att transformera lager av information till ett visuellt medium, och på så sätt tillåta mänsklig perception att snabbt extrahera värdefull information och utläsa mönster. Det här var en experimentell, design-orienterad, forskningsstudie med syftet att utforska ifall en informationsvisualisering av mikrotjänsters relationer kombinerat med system-hälso-data kunde hjälpa utvecklare på ett svenskt förvaltningsföretag av digitala rättigheter (DRMC) att hitta grundorsaken till felaktiga mikrotjänster samt utöka observerbarhet och beslutstöd, d.v.s. förenkla felhanteringsprocessen. För att utforska detta problem så utvecklades en prototyp som testades genom att låta tio utvecklare på DRMC utföra ett antal olika uppgifter samt svara på en semi-strukturerad intervju. Resultatet visade på att den föreslagna lösningen möjliggjorde en välkommen överblick över systemets hälsa och relationer, men också att den saknade möjligheten att effektivt fokusera på specifika tjänster, vilket ledde till att grundorsaksproblem var svåra att hitta. Visualiseringar som denna verkar fungera bäst för att presentera en överblick av ett system, snarare än ett fokus på specifika tjänster. Framtida forskning skulle kunna utföras för att utreda hur visualiseringar effektivt kan återge komplexa dataset utan att förlora fokus på specifika delar, samt hur externa faktorer kan integreras.
19
Zanella, Gilberto Luiz. "Sistema radicular no melhoramento genético do feijão (Phaseolus vulgaris L.)." Universidade do Estado de Santa Catarina, 2016. http://tede.udesc.br/handle/handle/2406.
Full textAbstract:
Submitted by Claudia Rocha (claudia.rocha@udesc.br) on 2018-03-01T13:14:10Z
No. of bitstreams: 1
PGPV16MA221.pdf: 709992 bytes, checksum: 01719d263cce161954dd5a4f4c6a9805 (MD5)Made available in DSpace on 2018-03-01T13:14:10Z (GMT). No. of bitstreams: 1 PGPV16MA221.pdf: 709992 bytes, checksum: 01719d263cce161954dd5a4f4c6a9805 (MD5) Previous issue date: 2016-12-19
Grain yield in bean (Phaseolus vulgaris L.) is highly affected by abiotic factors such as low soil fertility, water deficiency and high temperatures. The development of new cultivars, more efficient in the absorption of water and nutrients, has been the objective of the vegetal improvement. In this sense, the improvement of the root system, morphology, architecture and root distribution has been focused. The objective of this work was to determine the main component of the genetic variance of the root distribution in beans and to define selection strategies for the improvement of this character. An experiment comprising 40 genetic constitutions, 12 segregating populations in the F4, F5 and F6 generations and 4 fixed populations (parents) was developed during the agricultural years of 2014/15 and 2015/16. The treatments were arranged in increased blocks of Federer with 3 replicates. When the genetic constitutions showed full flowering, profiles were perpendicular to the sowing line and a gradient was placed for the quantification of the root system. The root distribution was evaluated in the binary system (denomination of presence (1) and absence (0) of the roots in each grid of the gradient). An analysis of variance and contrasts of non-orthogonal means (P < 0.05) were performed to test the hypothesis of the study. Both the segregating progenies and the parents have equal root distribution between the evaluation years, 2014/15 and 2015/16. The F4 progenies do not differ in relation to the root distribution when compared to their parents. The progenies (F4, F5 and F6) when compared also did not present significant differences. Throughout the segregating generations, the maintenance of the populations by self-fertilization and consequently the increase of the loci in homozygous resulted in the maximum expression of inbreeding. Thus, considering the predominance of the additive genetic variance and aiming at the formation of a pure line, it is recommended that the root distribution in bean be evaluated from the F4 generation
O rendimento de grãos na cultura do feijão (Phaseolus vulgaris L.) é altamente afetado por fatores abióticos como baixa fertilidade do solo, deficiência hídrica e altas temperaturas. O desenvolvimento de novas cultivares, mais eficientes na absorção de água e nutrientes, tem sido objetivo do melhoramento vegetal. Nesse sentido, tem-se dado enfoque a melhoria do sistema radicular, da morfologia, arquitetura e distribuição radicular. O objetivo do trabalho foi determinar o principal componente da variância genética da distribuição radicular em feijão e definir as estratégias de seleção para o melhoramento deste caráter. Para tanto, um experimento compreendendo 40 constituições genéticas, sendo 12 populações segregantes nas gerações F4, F5 e F6 e 4 populações fixas (genitores) foi desenvolvido durante os anos agrícolas de 2014/15 e 2015/16. Os tratamentos foram dispostos em blocos aumentados de Federer com 3 repetições. Quando as constituições genéticas apresentaram pleno florescimento foram abertos perfis perpendiculares à linha de semeadura e colocado um gradiente para a quantificação do sistema radicular. A distribuição da raiz foi avaliada no sistema binário (denominação de presença (1) e ausência (0) das raízes em cada quadrícula do gradiente). Foi realizada uma análise de variância e contrastes de médias não ortogonais (P < 0,05), para testar as hipóteses do estudo. Tanto as progênies segregantes quanto os genitores apresentam distribuição radicular igual entre os anos de avaliação, 2014/15 e 2015/16. As progênies F4 não apresentam diferença em relação ao caráter distribuição radicular quando comparadas aos seus genitores. As progênies (F4, F5 e F6) quando comparadas também não apresentam diferenças significativas. Ao longo das gerações segregantes, a manutenção das populações por autofecundação e consequentemente o aumento dos locos em homozigose proporcionaram a máxima expressão da endogamia. Assim, visto a predominância da variância genética aditiva e visando a formação de uma linha pura, recomenda-se que o caráter distribuição radicular em feijão seja avaliado a partir da geração F4
20
Alvarez, Flores Ricardo Andrés. "Réponses morphologiques et architecturales du système racinaire au déficit hydrique chez des Chenopodium cultivés et sauvages d'Amérique andine." Thesis, Montpellier 2, 2012. http://www.theses.fr/2012MON20138/document.
Full textAbstract:
Le genre Chenopodium comprend environ 150 espèces réparties sur l'ensemble du globe et établies dans une large gamme de milieux. En Amérique du Sud, différentes espèces, cultivées comme C. quinoa Willd. et C. pallidicaule Aellen, ou sauvages comme C. hircinum Schrader, sont distribuées sur des gradients pédoclimatiques allant du niveau de la mer au Chili, jusqu'à plus de 4000 m d'altitude sur l'altiplano boliviano-péruvien, sur des sols plus ou moins profonds et riches en nutriments, et sous des climats allant du tropical humide jusqu'au froid aride. Ces espèces sont phylogénétiquement apparentées, et on admet généralement que C. quinoa a été domestiqué à partir de C. hircinum et qu'une partie de son génome proviendrait de C. pallidicaule. Leur large distribution dans des écosystèmes naturels ou agricoles et leur plus ou moins grande tolérance aux contraintes du milieu, font de ce groupe d'espèces un modèle intéressant pour examiner la diversité des réponses des plantes, notamment face à la faible disponibilité en eau dans le sol. La totalité de l'eau nécessaire à la vie de ces plantes passant par le système racinaire, nous nous sommes intéressés aux variations intra- et interspécifiques de l'architecture et de la croissance des racines et à leurs réponses au déficit hydrique, en faisant l'hypothèse que les plantes provenant d'un milieu aride ou d'un système de culture à faible usage d'intrants, ont développé des traits racinaires qui leurs permettent d'accroître l'acquisition des ressources du sol. Pour tester cette hypothèse nous avons comparé la croissance et le développement racinaire de plantes de deux écotypes de C. quinoa de régions plus ou moins arides, et de populations de C. pallidicaule et de C. hircinum, placées dans des conditions de culture contrôlées non limitantes ou déficitaires en eau, en pots et en rhizotrons. Les principaux résultats de ce travail de thèse montrent que, malgré de grandes différences dans la production de biomasse et la morphologie aérienne, les populations étudiées présentent toutes la même typologie racinaire. Elles diffèrent entre elles par plusieurs traits d'architecture et de morphologie racinaire qui déterminent la capacité d'exploration et d'exploitation des ressources du sol. Certains de ces traits, comme la vitesse d'élongation de la racine principale, présentent une grande plasticité de réponse au déficit hydrique. D'autres traits, comme la longueur spécifique des racines, sont moins plastiques mais présentent des différences interspécifiques importantes. Ces variations de l'architecture des plantes forment des syndromes adaptatifs favorisant la survie des plantes dans les milieux les plus contraignants. Mots clés : Chenopodium quinoa, Chenopodium hircinum, Chenopodium pallidicaule, système racinaire, architecture racinaire, topologie racinaire, ontogénie, rhizotron, élongation racinaire, analyses de croissance, espèces cultivées, espèces sauvages, croissance racinaire, morphologie racinaireThe genus Chenopodium comprises about 150 species distributed all around the world and over a wide range of environments. In South America, differents species, either cultivated as C. quinoa Willd. and C. pallidicaule Aellen, or wild as C. hircinum Schrader, are distributed over pedoclimatic gradients from the sea level in Chile, up to an altitude of 4000 m in the altiplano of Bolivia and Peru, on soils more or less thick and rich in nutrients, and under climates from tropical humid to arid and cold. These species are phylogenetically related, and it is generally admitted that C. quinoa was domesticated from C. hircinum and that part of its genome comes from C. pallidicaule. Their wide distribution in natural and crop ecosystems and their more or less strong tolerance to environmental constraints, make this group of species an interesting model for examining the diversity of responses of the plants, in particular facing a low disponibility of resources in the soil. As all the water necessary for the life of the pass through the root system, we focused our interest in the intra- and interspecific variations in the root growth and architecture, and their responses to the water deficit, with the hypothesis that plants from arid habitats or from low-input agrosystems, developed root traits that allowed them to increase the acquisition of resources in the soil. To test this hypothesis we compared the root growth and development in plants of two ecotypes of C. quinoa from more or less arid regions, and of populations of C. pallidicaule and C. hircinum, placed under non-limiting or water deficit growth conditions, in pots and in rhizotrons. The main results of this research show that, despite large differences in biomass production and morphology of the aerial plant part, the studied populations showed the same root typology. They differed by several traits of root architecture and morphology which control the capacity of the plant to explore and exploit the soil resources. Some of these traits, such as the taproot elongation rate, showed a high plasticity in response to the water deficit. Other traits, like the specific root length, were less plastic but showed large interspecific differences. These variations in plant root architecture conforms adaptive syndromes that favor the plant survival in the most limiting environments. Key words : Chenopodium quinoa, Chenopodium hircinum, Chenopodium pallidicaule, root system, root architecture, topological index, ontogeny, rhizotron, root elongation, plant growth analysis, cultivated species, wild species, root growth, root morphology
21
Saint, Cast Clément. "Modélisation du développement architectural, de l'acclimatation au vent dominant et de l'ancrage du système racinaire du pin maritime." Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0018/document.
Full textAbstract:
Plus de la moitié des pertes de bois dans les forêts européennes sont dues aux tempêtes. Une connaissance des mécanismes impliqués dans la stabilité mécanique des arbres est alors capitale. L’ancrage de l’arbre dans le sol constitue l’une des composantes principales du maintien mécanique de l’arbre. Il est principalement déterminé par l’architecture du système racinaire et son interaction mécanique avec le sol. Au cours de son développement, l’arbre modifie ses dimensions et se complexifie. Plus particulièrement, le système racinaire semble s’acclimater (ex : croissance en diamètre plus importante) aux déformations engendrées par le vent. L’ensemble de ces modifications conduit à une évolution des mécanismes à l’origine de l’ancrage au cours du développement de l’arbre. L’étude expérimentale de cette fonction est compliquée car les racines sont difficilement mesurables en continu dans le sol. Nous avons alors mis au point une approche numérique pour décrire la croissance du système racinaire et la distribution des déformations dues au vent. Une grande base de données structurée en chronoséquence de systèmes racinaires numérisés (Pinus pinaster) a été mobilisée. Comme l’étude de la structure et des fonctions des racines est plus efficiente quand la différentiation entre racines est prise en compte, nous avons d’abord formalisé les types racinaires du système racinaire du pin maritime à partir d’une technique de classification (« k-means clustering ») réalisée avec quatre variables. La classification des racines latérales du pin maritime nous a permis d’identifier 5 types racinaires au cours du développement du pin maritime. Ce regroupement explique 70% de la variabilité de notre base de données. Chaque système racinaire est caractérisé par trois grosses racines horizontales émises par la souche. Les racines montrent une forte différentiation pour leur tropisme, avec une direction de croissance soit horizontale soit verticale. La structure de la partie centrale du système racinaire est pratiquement complète dès l'âge de 4 ans. Sur la base des types racinaires identifiés, nous avons calibré un modèle architectural (RootTyp ; Pagès et al. 2004) pour le pin maritime. Treize paramètres pour chaque type racinaire ont été estimés par l’intermédiaire de la base de données, d’informations issues de la littérature et d’une procédure d'optimisation. Une modélisation réaliste du système racinaire jusqu'à 50 ans n’a pu être obtenue qu'en implémentant au modèle RootTyp de nouveaux processus biologiques : la diminution de la ramification avec la croissance de la racine et la diminution de la vigueur des racines avec l'ordre de ramification. Malgré ces améliorations, les systèmes racinaires de la base de données présentent des diamètres plus importants à proximité de la souche par rapport aux systèmes racinaires simulés. Ce biais systématique est principalement attribué à l’acclimatation des racines au vent dominant. Les altérations de croissance dues aux contraintes pédologiques ont également été implémentées grâce à l’amélioration du module de sol du modèle architectural.Enfin, pour comprendre les mécanismes à l’origine de l’acclimatation des racines nous avons combiné plusieurs modèles pour prédire la distribution spatiale des déformations dans des maquettes simplifiées de systèmes racinaires à 4, 6 et 13 ans, pour trois régimes de vent spécifiques à la région étudiée. D’après les simulations, les déformations des racines sous l'effet du vent diminuent avec l’âge, en raison de l’augmentation de la rigidité des racines. Cela suggère une plus forte réponse thigmomorphogénétique aux stades jeunes. Les modifications structurelles et anatomiques du système racinaire par acclimatation au vent s’expliquent principalement par les distributions des déformations et des contraintes dans les racinesStorms cause more than 50% of the timber loss in European forests. However, forest tree anchorage mechanisms throughout their lifespan are not fully understood, especially the strong acclimation of root systems to common winds. This lack of knowledge is mainly due to technical difficulties: neither the root structure nor the mechanical contribution of the roots could be characterized continually. Thus we set up a numerical approach to model the development of the root system and to describe the strains resulting from common winds. This generic approach has been developed using Pinus pinaster grown in sandy soils as model species.Seven datasets of excavated root systems from 0 to 50 years were employed. The assessment of root structure and functions is more powerful if the differentiation of root system in several root types is considered. We first proposed an automatic classification of roots with the k-means clustering algorithm. Four root traits were chosen as classifiers, including three geometric architectural traits, which can be precisely assessed whatever the tree/root age. Clustering yielded similar five groups of laterals roots at all ages, explaining 70% of the variability. The three largest lateral roots per tree were all horizontal roots branching from stump and the other lateral roots show a large differentiation for tropism: nearly all the roots were horizontal or vertical roots. The framework of the central part of the root system can be almost completed in 4-year-old trees (3.5 cm collar diameter). We then calibrated the existing RootTyp (Pagès et al. 2004) architectural model for P. pinaster for each of the root types defined by the cluster analysis. We used the database combined with a literature review and an optimization method to get accurate values for 13 parameters by root types. We devoted effort to validate our model calibration. In order to model architecture of the root system, damping properties had to be implemented to yield realistic outputs up to the mature stage. Branching varied as a function of distance from the root base, and growth capacity decreased with branching order. Nevertheless, the root diameters of simulated root systems were generally underestimated. This was certainly due to root growth plasticity to the prevailing wind, an acclimation facet not taken into account at this calibration step. Growth alterations due to a cemented horizon were reproduced using the new calibrated soil module. Then, the wind acclimation of roots was numerically investigated by examining the root mechanical stimuli due to wind. A chain of biomechanical models was used to predict the spatial distribution of stress and strain in simplified root systems at 4, 6 and 13-year-old as a result of three levels of usual winds. According to simulations, the strain amplitude decreased with tree growth due to the increasing root system stiffness. This suggests larger thigmomorphogenetic responses at young stages. The modifications of the structural and wood root properties related to wind acclimation were largely explained by the stress and strain distribution in the root system
22
Yang, Ming. "Ancrage racinaire des arbres : modélisation et analyses numériques des facteurs clés de la résistance au vent du Pinus pinaster." Thesis, Bordeaux, 2014. http://www.theses.fr/2014BORD0279/document.
Full textAbstract:
Les tempêtes hivernales causent des pertes en bois qui s’élèvent à 50% du volume des dégâts dans les forêts européennes. Les phénomènes de déracinement des arbres (chablis) sont les plus fréquents or ils sont encore mal compris. Cette thèse vise à mieux comprendre le processus de déracinement de l’arbre et à identifier les traits structuraux et matériels (racines, sol) ayant un effet du premier ordre sur l’ancrage racinaire dans le cas du Pinus pinaster. Un modèle d’éléments finis a été développé et permis de simuler et suivre la chronologie des ruptures successives au cours du déracinement. Un seuil de rupture globale de l’ancrage est ainsi défini comme une résultante de l’architecture et de la résistance des matériaux en jeu (racines, sol). Cela devrait permettre à terme d’améliorer les modèles de risque au vent qui actuellement n’incluent pas de relation mécaniste pour le chablis. Dans la même logique, nous nous sommes appuyés sur les données expérimentales pour construire une architecture simplifiée du système racinaire du P. pinaster. L’importance des différentes composantes sur le mécanisme d’ancrage a été étudiée et le rôle essentiel joué par le pivot et les racines traçantes montré. Ce résultat confirme de nombreuses études expérimentales et théoriques et pour la première fois permet de quantifier ces effets. Le nombre de paramètres pertinents pourra ainsi être réduit pour exprimer l’ancrage. Cela ouvre des perspectives intéressantes pour simplifier l’utilisation du modèle pour l’appliquer à d’autres espèces, d’autres conditions de sol et différentes pratiques sylvicolesWinter storms cause 50% of wood damage by volume to European forests. Tree uprooting isthe most frequent phenomenon during storms ; however the mechanism is not well understood.This thesis aims to better understand the tree uprooting process and to identify both rootstructural features and material properties which have first-order effects on tree anchoragestrength for the case ofPinus pinaster. A Finite Element Model has been developed and allowedsimulating and tracking the sequential root breakage during the course of tree overturning. Anoverall tree anchorage strength is thus defined as the resultant of contribution of root systemarchitecture and material strength (roots, soil). This would allow improving the risk modelswhich currently don’t include any mechanistic relationships to describe tree uprooting. In thesame spirit, we have relied on root architectural data to build a simplified root system patternwith features ofP. pinaster. Importance of different root components has been studied andthe essential role of the taproot and shallow roots demonstrated. This result has confirmednumerous experimental and theoretical studies and for the first time quantified these impacts.Therefore the number of relevant parameters can be reduced to express overall root anchorage.This opens new prospects to simplify the model in order to apply to other species under othersoil conditions and considering different silvicultural practices
23
Chenlemuge, Tselmeg [Verfasser], Markus [Akademischer Betreuer] Hauck, Christoph [Akademischer Betreuer] Leuschner, and Dirk [Akademischer Betreuer] Gansert. "Drought Adaptation of the Fine Root System and Hydraulic Architecture of Larix sibirica at its Southern Distribution Limit General introduction / Tselmeg Chenlemuge. Gutachter: Markus Hauck ; Christoph Leuschner ; Dirk Gansert. Betreuer: Markus Hauck." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2015. http://d-nb.info/1065044720/34.
Full text
24
Ghestem, Murielle. "Quelles propriétés racinaires et quelles espèces-outils pour la stabilisation des points chauds de dégradation en Chine du Sud ?" Phd thesis, AgroParisTech, 2012. http://pastel.archives-ouvertes.fr/pastel-00855792.
Full textAbstract:
La Chine est actuellement confrontée à de sérieux problèmes environnementaux et est listée parmi les pays qui contribuent le plus à la pollution et à la destruction de l'environnement mondial. En particulier, la Chine du Sud est une zone naturellement sujette aux glissements de terrain à cause de conditions tectoniques, climatiques et anthropiques particulièrement défavorables. Depuis la fin des années 1990, l'Etat chinois a mis en place des politiques de reforestation de grande envergure. mais il existe des lacunes de connaissances qu'il convient de combler. En particulier, le choix des espèces les plus adaptées n'est pas aisé parce que les processus par lesquels les plantes stabilisent les pentes ont besoin d'être mieux compris.En introduction, afin de mieux préciser les périmètres qui cadrent cette thèse, sont présentées la situation de la Chine du Sud au regard des glissements de terrain, la discipline d'éco-ingénierie et les solutions qu'elle peut apporter. Ainsi, ce travail (i) se concentre sur des espèces végétales locales, (ii) se limite aux glissements de terrain superficiels, et (iii) concerne à la fois les processus mécaniques et hydriques entre le sol et les racines. A l'intérieur de ces cadres, la thèse a pour objectif de répondre à la question scientifique : quels sont les propriétés racinaires qui influencent la stabilisation des pentes ? La réflexion est ensuite appliquée aux plantes de Chine du Sud afin d'identifier les meilleures espèces-outils. Pour répondre à cette question, à la fois les données de terrain (en Chine du Sud), les expériences de laboratoire (en France) et la formulation de concepts sont mobilisées. Les résultats sont organisés en deux chapitres. Le premier pose la question de l'efficacité de la présence de racines pour stabiliser les pentes, tous d'abord sous l'angle des processus mécaniques, puis sous l'angle des processus hydriques. Le deuxième chapitre permet d'identifier un panel de traits pertinents et non redondants évaluant l'efficacité d'une espèce pour la stabilisation des pentes puis s'appuie sur ce panel afin de sélectionner les espèces chinoises les plus efficaces. Enfin, la discussion aborde les limites de ce travail et propose de nouvelles pistes de recherche.Du point de vue mécanique comme du point de vue hydrique, c'est la conjonction des effets des racines de structure et des racines fines qui importe. Les racines de structure sanas racines fines ne sont pas optimales et peuvent même faire apparaître des lignes de fragilité. Plus précisément, les racines de structure sont particulièrement bienvenues vers l'aval de la pente pour des raisons à la fois mécaniques et hydriques. Les racines fines seules ne sont pas optimales non plus, elles peuvent faire apparaître localement des zones de faiblesse qui, si elles sont proches, participeront au déclenchement d'un glissement de terrain. Des ramifications racinaires denses améliorent la stabilité mécanique. Orientées vers l'aval de la pente, elles améliorent la stabilité hydrique. Les autres traits racinaires pertinents pour évaluer l'efficacité des racines à stabiliser le sol sont la contrainte et la déformation maximale en tension, la concentration en azote et la concentration en sucres solubles.
25
El, Debbagh Nabil. "Analyse de la diversité de processus de développement racinaire chez les Prunus : aptitude au bouturage et réponses à la contrainte hydrique." Thesis, Avignon, 2016. http://www.theses.fr/2016AVIG0676/document.
Full textAbstract:
La sélection des nouveaux porte-greffes du genre Prunus a pour principal objectif d’utiliser lavariabilité génétique existant au sein des différentes espèces de Prunus afin de créer un matérielvégétal innovant, performant au plan agronomique et résistant à différentes contraintes biotiques etabiotiques. L’exploitation de la variabilité génétique s'appuie sur le phénotypage des différentsindividus présents dans les collections de ressources génétiques pour les caractères recherchés. Celapermet de sélectionner des génotypes spécifiques pour améliorer un trait donné.Dans cette étude constituée de deux parties, nous avons exploré la diversité génétique au seindu genre Prunus pour ce qui concerne deux traits importants : l’aptitude au bouturage et les réponsesde certains porte-greffes à la contrainte hydrique.Dans la première partie l’aptitude au bouturage ligneux a été explorée dans une collectiongénétique de 222 génotypes. Les résultats obtenus montrent une variabilité considérable entre les sousgenresAmygdalus et Prunophora et également une variabilité interspécifique au sein de chaque sousgenre.La réussite au bouturage est nettement améliorée chez les hybrides interspécifiques dont un desparents appartient à l’espèce P cerasifera.Dans la deuxième partie nous avons étudié les réponses à la contrainte hydrique chez neufgénotypes couramment utilisés comme porte-greffes. Nous avons comparé trois régimes hydriquesdifférents : témoins, stressés et recouvrés. L’humidité du substrat est maintenue à la capacité au champtout au long de l’expérience pour les plants témoins, par contre l’arrosage a été arrêté pendant 14 jourspour les plants stressés, puis il a été repris pendant 10 jours pour les plants recouvrés. Durant cetteexpérience, nous avons effectué des mesures morphologiques et physiologiques sur la partie aérienneainsi que des excavations à la fin de chaque phase pour examiner les modifications au niveau dusystème racinaire. Sur la partie aérienne, la contrainte hydrique a provoqué une diminutionsignificative de la photosynthèse nette, de la transpiration totale, de la conductance stomatique, et del’expansion des feuilles.Le système racinaire a répondu à cette contrainte par plusieurs modifications. D’abord, le ratio racines/pousses a augmenté pour 4 génotypes (GF305, GF677, Montclar et Myrobolan1254). Ensuite, lesdifférents traits de l’architecture racinaire ont montré des modifications sous l’effet de la contraintehydrique : la longueur de la zone apicale non ramifiée (LZANR) qui traduit l’élongation racinaire,ainsi que les diamètres apicaux des racines ont diminué chez tous les génotypes. Par conséquent lesracines se sont affinées et ont réduit leur croissance en longueur. Produire des racines plus finesaugmente la surface de contact entre les racines et le sol et améliore la capacité d’absorption. Unediminution de la distance inter-ramification a été observée chez les plants stressés. Cette modificationpourrait s’expliquer par le fait que les plantes produisent plus de racines latérales en profondeur oùl’eau est souvent plus disponible. De plus, les racines latérales produites étaient également plus fines.Au plan qualitatif, les génotypes ont eu des réponses semblables, mais l’intensité de la réponse a variéselon les génotypesIn breeding programs of Prunus rootstocks the aim is to use the existing genetic variabilitywithin Prunus species in order to create new rootstock genotypes with excellent agronomic traits, andimproved resistance to biotic and abiotic stresses.Exploitation of the genetic variability is based on the evaluation of phenotypic variation amongindividuals within genetic collections for desirable traits. This make possible to select specificgenotypes to improve a given trait.This study consists of two parts; we explored the genetic diversity within the genus Prunusregarding two important characteristics: rooting ability of hardwood cuttings and responses of somerootstocks to water stress.In the first part, rooting ability of hardwood cuttings was evaluated among 222 genotypespreserved in genetic collection. The results show considerable variability among the sub genusAmygdalus, Prunophora, and also an interspecific variability within each of them. Rooting ability byhardwood cutting was significantly improved in interspecific hybrids if one parent belongs to Pcerasifera species.In the second part of this study we studied the responses of nine genotypes, commonly usedrootstocks, to water stress. We applied three treatments: control, water stress and recovering.Soil moisture was maintained at field capacity through all stages of the experiment for the controlplants. On the contrary we stopped watering during 14 days for the stressed plants, and then we rewateredthe recovered plants for 10 days.During this experience, we performed morphological and physiological measurements on the aboveground parts of plants and we excavated plants at the end of each phase to observe root systemmodifications.Aboveground parts of plant responded to water stress by a significant decrease in net photosynthesis,total transpiration, stomatal conductance and leaf expansion.Root system responded to water stress by several modifications:Four genotypes (GF305, Montclar, GF677 and Myrobolan) showed a significant increase in root toshoot ratio under drought conditions. We also detected morphological modifications on the differenttraits of root architecture in response to water stress.The length of the apical unbranched zone LAUZ and the apical diameter were decreased forall genotypes, consequently, roots became finer and reduced their rate of elongation. Fine rootsenhance the surface of contact between roots and soil which in turn improve the acquisition of waterunder drought condition.The inter-branch distance also responded, and it tended to decrease under the water stress treatment.The decrease in inter-branch distance can be explained by a production of more lateral roots in deeplayers, where water was more available, moreover these new laterals roots were also finer.Qualitatively, a common response to water stress was observed on the different traits of the rootsystem architecture, but we showed a genotypic effect determining the level of the response
26
Li, Jun-Wei, and 李潤威. "Mechanical Conversion Model of Shear Strength Increment Due to Root in Soil~Root System." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/33594888385997306189.
Full textAbstract:
碩士國立中興大學
水土保持學系所
97
In this study, two dimensional (2-D) finite element numerical simulations were carried out on the pull-out resistance and the shear strength of soil/root system of Indiacharcial trema. Based on the field investigations of Indiacharcial trema root morphology, one can establish a 2-D numerical model of soil/root system to simulate the pull-out test at field site. Through the comparison of simulated pull-out mechanical behaviors with those from measurements, the effectiveness of the proposed 2-D numerical procedures can be verified. It was indicated the simulated pull-out resistance versus pull-out displacement curve (or P~Lp curve) and the ultimate pull-out resistance Pu are in good agreement with those from measurement. Subsequently, a 2-D numerical model of soil/root system identical with the pull-out test was repeatedly used for the simulation of direct shear test to estimate the shear strength increment ΔSr resulted from root system. Eventually, using the numerical results of Pu and ΔSr values, a mechanical relationship between Pu and ΔSr (orΔSr=f(Pu) function) for soil/root system are proposed. The relationship offers the stability analysis of vegetated slope a convenient mechanical conversion model which enables a direct transformation of pull-out resistance into shear strength increment of root system and an immediate application to 2-D slope stability analysis. As a result, to establish an individual ΔSr=f(Pu) function for various plant roots using the large quantity of existing data bank from in-situ pull-out test in near future, it is suggested to regard the proposed working procedures as a practical and useful reference example.
27
Kuo, Wei-Jung, and 郭濰榕. "A Study on Soil Resistance Shear Strength Increment of Root System." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/mezv48.
Full textAbstract:
碩士中原大學
土木工程研究所
103
With the growth of concern about ecological and environmental issues in Taiwan, vegetation revetment engineering has become an essential method for stabilizing river embankment project in recent years. Based on researches of roots system mechanics, plant roots system for the calculation of soil shear increments has gradually come to light. This study refers to the pull-out test analysis of foundation piles, then derives a series of pull-out formula and the application of simplified roots system mechanics. Both theoretical concepts and situ test references were integrated to carry out the analysis of soil resistance shear strength, hope it can be applied to assess the safety and applicability of the vegetation revetment. Mechanical properties of the willow works revetment was mainly discussed for the entire study. Fazi river willow works revetment engineering in Taichung was chosen to be the situ pull-out test address. Two different types of test were conducted here, including direct shear tests on sampling soils and the situ pull-out tests of roots system, to acquire soil parameters using in the following derivation, which aimed to obtain the increments of resistance shear strength of roots system. Furthermore, for the purpose of assessing whether willow works revetment would reach the destruction situation, this study also considered the effect of stream drag force, destruction of the plants bend of mechanics led by water flow, and deriving pull-out formula as well as other theories. The consequence shows that willow works can achieve a high resist invasion strength, also indicates this ecological engineering methods can be achieved the resist destruction strength as same as traditional construction methods.
28
Huang, Bo-Shun, and 黃伯舜. "The Conversion Model of the Increased Shear Strength Due to Roots in Soil-Root System." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/51610330627195863145.
Full textAbstract:
博士中興大學
水土保持學系所
99
In this study, a mechanical conversion model was developed through numerical procedures to correlate the increased shear strength of soil-root system due to roots with plant root parameters of basal diameter of plant D, ultimate pull-out resistance of root Pu, and the average tensile strength of roots Tr. Meanwhile, the model can be used to determine the required strength parameters for the stability analysis of vegetated slope and expedite the efficiency of analysis. Firstly, three species of plants, namely, Trema orientalis (L.) Blume (India charcoal trema, ICT), Lagerstroemia subcostata Koehne (Subcostate crape myrtle, SCM), Hibiscus taiwanensis S. Y. Hu (Cotton rose, CR) commonly used for the slope vegetation in Taiwan were selected for the field investigations. In the investigation the basic properties of root system such as root morphology, root diameter, root area ratio, and root growth characteristics were surveyed in field site. Moreover, a series of laboratory tensile strength tests and in-situ pull-out tests were performed to determine the tensile strength of root material and the ultimate pull-out resistance of soil-root system respectively. Using the root morphology and root material parameters, one can establish a 2-D numerical model of soil-root system to simulate the in-situ pull-out behaviors and relevant parametric study. Through the comparisons of the simulated pull-out force versus pull-out displacement curves (or P-Lp curves) and the ultimate pull-out resistance of soil-root system Pu with those from measurements, the validities of the numerical model, simulation procedures and various input material parameters can be verified. Subsequently, the identical 2-D numerical model of soil-root system with that used in pull-out test was repeatedly adopted for the simulation of direct shear test to estimate the increased shear strength ΔSr of soil-root system due to roots. Eventually, integrating the data from : (1) field measurements: the dry root weight Wr, number of lateral root NLR, basal diameter of plant D, ultimate pull-out resistance Pu, (2) laboratory tests: the maximum tensile load of single root tmax, and (3) numerical simulations: the simulations of ultimate pull-out resistance Pus , increased shear strength due to roots ΔSr, one can propose four mechanical conversiton models for soil-root system: (1)ΔS r=f(D), (2)ΔSr=f(Pu), (3) ΔSr=f(D, Pu, Wr, NLR), and(4) ΔSr = f(Tr, Ar, As). The above four conversion models play an important role in the quantitative analyses of the stability of vegetated slope in which the models enable a fast estimation for the increased shear strength due to roots ΔSr through the associated physical and mechanical parameters of soil-root system.
29
Zurek, Paul Roman. "Quantitative Trait Locus Mapping Reveals Regions of the Maize Genome Controlling Root System Architecture." Diss., 2014. http://hdl.handle.net/10161/9399.
Full textAbstract:
Root system architecture (RSA) is the spatial distribution of roots of individual plants. As part of a collaborative effort I adapted a gellan gum based system for imaging and phenotyping of root systems in maize. This system was first used to perform a survey of 26 distinct maize varieties of the Nested Association Mapping (NAM) population. The analysis of these data showed a large amount of variation between different RSA, in particular demonstrating tradeoffs between architectures favoring sparse, but far reaching, root networks versus those favoring small but dense root networks. To study this further I imaged and phenotyped the B73 (compact) x Ki3 (exploratory) mapping population. These data were used to map 102 quantitative trait loci (QTL). A large portion of these QTL had large, ranging from 5.48% to 23.8%. Majority of these QTLs were grouped into 9 clusters across the genome, with each cluster favoring either the compact of exploratory RSA. In summary, our study demonstrates the power of the gellan based system to locate loci controlling root system architecture of maize, by combining rapid and highly detailed imaging techniques with semi-automated computation phenotyping.
Dissertation
30
Chapman, Kelly. "The roles of CEP-CEPR1 signalling in controlling root system architecture in Arabidopsis thaliana." Phd thesis, 2021. http://hdl.handle.net/1885/232589.
Full textAbstract:
Plants utilise their roots systems to acquire nutrients and moisture, in order to sustain growth and yield. To coordinate root growth plants must integrate multiple local and systemic signals, including metabolite and peptide hormones. In this thesis, the C-TERMINALLY ENCODED PEPTIDE (CEP) peptide hormone family and their corresponding major receptor, CEP RECEPTOR 1, were studied in Arabidopsis thaliana.
Lateral roots comprise the majority of the root system, however, the distinct mechanisms controlling their growth are poorly understood. Here, we identified novel roles for CEP-CEPR1 signalling in negatively controlling lateral root (LR) growth in response to photosynthetically-derived carbon. We demonstrated that cepr1 mutants had longer LRs in the presence of sucrose, which was due to a greater cell number in the LR meristem, and an increased length of mature LR cells. Transcriptomic analysis identified that sucrose upregulated CEP5-8 in two Arabidopsis ecotypes. In addition, genes with basally perturbed expression in cepr1-1 overlap with wild type sucrose-responsive genes significantly. We subsequently observed that exogenous CEP5 inhibited LR growth by reducing LR meristem size and mature cell length. This result is consistent with CEP-CEPR1 acting to curtail the extent of sucrose-dependent LR growth. Reciprocal grafting indicates LR growth inhibition requires CEPR1 activity in both local and systemic circuits. Our results reveal a new role for CEP-CEPR1 signalling in controlling LR growth in response to sucrose.
To further observe CEPR1-dependent changes in LR development, we developed a soil-based rhizobox system. This allowed us to view RSA over time in mature plants, and demonstrated that CEPR1 controls root system width in soil-grown Arabidopsis. The cepr1 mutants had a narrower RSA, which results from a steeper LR gravitropic set-point angle (GSA). Consistently, the application of CEP3 increased GSA in wild type but not in the CEP receptor mutants. Grafting showed that CEPR1 control of LR GSA occurred via the shoot only, and was, therefore, at least partially separable from its control of LR growth.
Auxin signalling is known to reduce LR GSA. Therefore, we examined if CEP-CEPR1 signalling controlled LR GSA via an intersection with auxin signalling. Both cepr1 mutants exhibited an increase in rootward auxin transport, suggesting that an alteration to auxin transport may be responsible for the steeper GSA in cepr1 mutants. Consistent with this hypothesis, the application of auxin to wild type shoots induced a steeper GSA and auxin transport inhibitors counteracted the steep GSA phenotype of the cepr1 mutant. Using a DII-VENUS auxin signalling reporter line, we showed that CEP3 treatment applied specifically to the shoots increased DII-VENUS fluorescence in roots within 2 hours.
Cytokinin acts as an anti-gravitropic offset in the determination of LR GSA. To assess if cytokinin and CEP-CEPR1 signalling intersected, we treated mutants defective in cytokinin signalling with CEP3. Consistent with an intersection, we showed that specific cytokinin pathway mutants have similar LR GSA phenotypes to cepr1 mutants. Conversely, we also found that cepr1-3 is partially resistant to the effects of tZ on LR GSA, suggesting that cytokinin and CEP-CEPR1 signalling converge in the control of LR GSA. However, when grown in soil rhizoboxes cytokinin pathway mutants did not fully phenocopy cepr1-3, indicating cytokinin alone is not sufficient to cause the steep RSA of cepr1 mutants. A mutant defective in specific CEP-CEPR1 downstream targets, cepd1,2, had a wild type-like RSA in soil. These results suggest that other downstream targets contribute to the control of RSA by CEP-CEPR1 and cytokinin signalling.
Collectively, these results indicate that CEP-CEPR1 signalling controls multiple facets of root growth and RSA in response to both nitrogen and carbon status.
31
Hsu, Chia-Pin, and 許家賓. "The shear strength increase provided by root system of three plant species（Linden hibiscus、Japannese mallotus, and China berry-tree）." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/28891958012255857820.
Full textAbstract:
碩士國立高雄第一科技大學
營建工程所
96
This research attempts to discuss three kind of plant root system growth state to provide the shearing strength increase with it the relations, plants by the achievement lives carries on plant of choice reference the stability of slope processing. The in situ direct shear test took root reinforced soil mass with vegetation（Linden hibiscus、Japannese mallotus, and China berry-tree） and soil mass without roots, and controls the soil moisture content in 12~14%. After test, investigation of plants roots, soil test, and tensile test for plants roots. In computation overall roots of plant，the result estimated the increment of peak shear strength (ΔS) offered by vegetation (Linden hibiscus) was around 9.1% of the root tensile strength (tR)；the increment of peak shear strength (ΔS) offered by vegetation (Japannese mallotus) was around 12.8% of the root tensile strength (tR)；the increment of peak shear strength (ΔS) offered by vegetation (China berry-tree) was around 9.6% of the root tensile strength (tR). The computation of roots which pass the shear cross-section only, the result estimated the increment of peak shear strength (ΔS) offered by vegetation (Linden hibiscus) was around 1.34% of the root tensile strength (tR)；the increment of peak shear strength (ΔS) offered by vegetation （Japannese mallotus）was around 24.1% of the root tensile strength (tR)；the increment of peak shear strength (ΔS) offered by vegetation (China berry-tree) was around 1.49% of the root tensile strength (tR). Plant root morphology have an top root of vegetation（Japannese mallotus）better than by the lateral root primarily of vegetation（Linden hibiscus、China berry-tree）on increase of shearing strength of roots.
32
Bu, Lake. "Design of secure and trustworthy system-on-chip architectures using hardware-based root-of-trust techniques." Thesis, 2019. https://hdl.handle.net/2144/36148.
Full textAbstract:
Cyber-security is now a critical concern in a wide range of embedded computing modules, communications systems, and connected devices. These devices are used in medical electronics, automotive systems, power grid systems, robotics, and avionics. The general consensus today is that conventional approaches and software-only schemes are not sufficient to provide desired security protections and trustworthiness.
Comprehensive hardware-software security solutions so far have remained elusive. One major challenge is that in current system-on-chip (SoCs) designs, processing elements (PEs) and executable codes with varying levels of trust, are all integrated on the same computing platform to share resources. This interdependency of modules creates a fertile attack ground and represents the Achilles’ heel of heterogeneous SoC architectures.
The salient research question addressed in this dissertation is “can one design a secure computer system out of non-secure or untrusted computing IP components and cores?”. In response to this question, we establish a generalized, user/designer-centric set of design principles which intend to advance the construction of secure heterogeneous multi-core computing systems. We develop algorithms, models of computation, and hardware security primitives to integrate secure and non-secure processing elements into the same chip design while aiming for: (a) maintaining individual core’s security; (b) preventing data leakage and corruption; (c) promoting data and resource sharing among the cores; and (d) tolerating malicious behaviors from untrusted processing elements and software applications.
The key contributions of this thesis are:
1. The introduction of a new architectural model for integrating processing elements with different security and trust levels, i.e., secure and non-secure cores with trusted and untrusted provenances;
2. A generalized process isolation design methodology for the new architecture model that covers both the software and hardware layers to (i) create hardware-assisted virtual logical zones, and (ii) perform both static and runtime security, privilege level and trust authentication checks;
3. A set of secure protocols and hardware root-of-trust (RoT) primitives to support the process isolation design and to provide the following functionalities: (i) hardware immutable identities – using physical unclonable functions, (ii) core hijacking and impersonation resistance – through a blind signature scheme, (iii) threshold-based data access control – with a robust and adaptive secure secret sharing algorithm, (iv) privacy-preserving authorization verification – by proposing a group anonymous authentication algorithm, and (v) denial of resource or denial of service attack avoidance – by developing an interconnect network routing algorithm and a memory access mechanism according to user-defined security policies.
4. An evaluation of the security of the proposed hardware primitives in the post-quantum era, and possible extensions and algorithmic modifications for their post-quantum resistance.
In this dissertation, we advance the practicality of secure-by-construction methodologies in SoC architecture design. The methodology allows for the use of unsecured or untrusted processing elements in the construction of these secure architectures and tries to extend their effectiveness into the post-quantum computing era.
33
Benešová, Šárka. "Vývojová terminace aktivity apikálního meristému kořene." Master's thesis, 2016. http://www.nusl.cz/ntk/nusl-351460.
Full textAbstract:
Development Related Termination of the Root Apical Meristem Activity Abstract Root system architecture is modulated through growth and branching of individual roots, while the growth is strictly regulated via long term apical meristem (RAM) maintenance and cell elongation. RAM activity is not consistent during root on- togeny, which was shown in several dicotyledonous species as change in root meristem structure and decline in root growth rate during individual root development. This thesis is focused on changes in extent and arrangement of meristematic tissues and their derivatives within adventitious roots of Acorus calamus and Oryza sativa during long term cultivation. Changes in meristem and elongation zone length, the root cap length, radial tissue complexity, as well as the changes in root hair emergence, etc., are put into relation with quantified expression level of selected important regulatory elements taking part in RAM maintenance (WOX and SCR family transcription factors). Methodology and approach for future research in this field are outlined. Keywords: Root, Apical Meristem, Root System Architecture, RAM Termination
34
Chenlemuge, xxx. "Drought Adaptation of the Fine Root System and Hydraulic Architecture of Larix sibirica at its Southern Distribution Limit General introduction." Doctoral thesis, 2014. http://hdl.handle.net/11858/00-1735-0000-0023-9980-9.
Full text
35
Alqahtani, Mashael Daghash Saeed. "The role of PQL genes in response to salinity tolerance in Arabidopsis thaliana and barley." Diss., 2019. http://hdl.handle.net/10754/660184.
Full textAbstract:
Increasing salinity is a worldwide problem, but the knowledge on how salt enters
the roots of plants remains largely unknown. Non-selective cation channels
(NSCCs) have been suggested to be the major pathway for the entry of sodium
ions (Na+) in several species. The hypothesis tested in this research is that PQ
loop (PQL) proteins could form NSCCs, mediate some of the Na+ influx into the
root and contribute to ion accumulation and the inhibition of growth in saline
conditions. This is based on previous preliminary evidence indicating similarities in
the properties of NSCC currents and currents mediated by PQL proteins, such as
the inhibition of an inward cation current mediated by PQL proteins by high external
calcium and pH acidification. PQL family members belonging to clade one in
Arabidopsis and barley were characterized using a reverse genetics approach,
electrophysiology and high-throughput phenotyping. Expression of AtPQL1a and
HvPQL1 in HEK293 cells increased Na+ and K+ inward currents in whole cell
membranes. However, when GFP-tagged PQL proteins were transiently
overexpressed in tobacco leaf cells, the proteins appeared to localize to
intracellular membrane structures. Based on q-RT-PCR, the levels of mRNA of
AtPQL1a, AtPQL1b and AtPQL1c is higher in salt stressed plants compared to
control plants in the shoot tissue, while the mRNA levels in the root tissue did not
change in response to stress. Salt stress responses of lines with altered
expression of AtPQL1a, AtPQL1b and AtPQL1c were examined using RGB and
chlorophyll fluorescence imaging of plants growing in soil in a controlled
environment chamber. Decreases in the levels of expression of AtPQL1a,
AtPQL1b and AtPQL1c resulted in larger rosettes, when measured seven days
after salt stress imposition. Interestingly, overexpression of AtPQL1a also resulted
in plants having larger rosettes in salt stress conditions. Differences between the
mutants and the wild-type plants were not observed at earlier stages, suggesting
that PQLs might be involved in long-term responses to salt stress. These results
contribute towards a better understanding of the role of PQLs in salinity tolerance
and provide new targets for crop improvement.