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Guyonnet, Julien. "Effet de la stratégie de gestion des ressources des plantes sur l’investissement dans l’exsudation racinaire, et les conséquences sur les communautés bactériennes". Thesis, Lyon, 2017. http://www.theses.fr/2017LYSE1008.
Pełny tekst źródłaRoot exudation is known to influence microbial communities functioning, in particular those involve in nitrogen cycle. (Haichar et al, 2012). It’s linked to plant physiology, which can be evaluated with functional traits, allowing a plant distribution in function of their performance in their environment. Thus, we can distinguish competitive species, with higher photosynthetic capacity and rapid rates of N acquisition, conservative species with the opposite characteristics (Aerts & Chapin, 1999) and intermediate plants, with intermediate characteristics.The objective of this work is to determinate the influence of nutrient management strategiy of 6 poaceae, along a strategies gradient from conservative strategy (Sesleria caerulea and Festuca paniculata), intermediate (Antoxanthum odoratum and Bromus erectus) to competitive strategy (Dactylis glomerata and Trisetum flavescens), on diversity and functioning of total and denitrifying communities.I) Firstly, we studied the link between the plant nutrient management strategy and the root exudates quantity in the root adhering soil (RAS). Then, we determined the influence of the rate of root exudation on potential microbial activities (respiration and denitrification), and with a DNA-SIP (Stable Isotope Probing) approach coupled to high-throughput sequencing, the influence of root exudation on the bacterial structure and diversity of communities colonizing the RAS and the root system. II) Secondly, we studied the link between the plant nutrient management strategy and the nature of molecules exuded in RAS and present in root extracts by analyzing primary metabolites profile to Festuca paniculata, Bromus erectus and Dactylis glomerata, respectively a conservative, an intermediate and a competitive plant. Then, we determined the influence of primary metabolites profile of each plant on semi-real denitrification of communities colonizing RAS of plants. III) Finally, an mRNA-SIP approach is in progress to determine the influence of exuded metabolites on active bacterial communities functioning and the expression of genes involved in denitrification process in RAS and root system. Our results show an influence of the nutrient management strategy on the rate of carbon exudation, the competitive plants exuding more than conservatives ones
Delamare, Jeremy. "Analyses de deux stratégies d’acclimatation à un stress thermique intense reposant sur une thermo-sensibilisation ou une sensibilisation médiée par des bactéries PGPR chez le colza et la caméline". Electronic Thesis or Diss., Normandie, 2023. http://www.theses.fr/2023NORMC243.
Pełny tekst źródłaThe on-going climate changes that we are facing are characterized in particular by modifications of temperature profiles in terms of intensity, duration and repetition of heat waves. These heat waves occur during the reproductive stages of the crops, which are also the most critical for seed yield elaboration and grain quality in crops. Oleaginous species such as rapeseed and camelina, are species particularly impacted by heat stress that cause yield penalties and a lower seed quality. Therefore, to cope with heat stress, it has become necessary to identify new acclimation levers that differ avec genetic and agronomic levers, such as strategies based on plants acclimation. Thermopriming which consist in priming the plants in a way to help them respond more rapidly, effectively, intensively and/or sensitively to heat by a prior exposure of a stress of the same nature could allow the plants to acclimate and develop appropriate response mechanisms. The plant inoculation with Plant Growth Promoting Rhizobacteria (PGPR)-type bacteria is also an acclimation lever increasingly studied, that limit the impacts of abiotic stress such as heat stress. However, although these two types of acclimation levers are mainly studied to limit stress impact on aboveground development and yield, few studies have observed their effects on root morphology and functions such as root exudation. In this thesis we analysed in rapeseed and camelina (i) the effects of a gradual increase in temperature prior a heat stress on yield and grain quality and on root morphology and exudation and (ii) the effects of inoculating two Pseudomonas with PGPR activities in order to limit the impact of heat stress on yield and grain quality. Moreover, in order to understand the impact of heat stress and PGPR inoculation (combined or not) on the plant and associated rhizosphere, the effects of these treatments were studied on root exudation, carbon (C) allocation in the soil-plant system, root morphological traits and soil microbial communities. Our results showed that rapeseed and camelina have contrasting strategies in terms of response to heat stress. Indeed, camelina seems to respond to the stress by increasing its investment to the roots thus improving the quality of exudation and stimulating the activity of microbial communities, unlike rapeseed, which seems to undergo heat stress. In addition, these two species respond differently to the two acclimation strategies applied. In rapeseed, thermopriming reduced C exudation and maintained yield and grain quality, whereas it had a more negative impact on exudation and root morphology in camelina. PGPR inoculation is an acclimation strategy that tends to limit the effects of heat stress on yield and grain quality in rapeseed. However, PGPRs act as an additional sink in rapeseed, impacting its development, exudation and the activity and composition of microbial communities in the rhizosphere. By contrast, camelina is slightly affected by the addition of PGPRs and seems to control the plant/bacteria interactions rather than be affected by them. In short, beneficial effects on plants of these acclimation levers have been evidenced. In addition, it could be interesting to integrate the effects of varietal selection on plant response strategies to stress, and in particular the variability of root functions and interactions with the rhizosphere, in the light of the varietal selection differentially undergone by rapeseed and camelina
Plum, Sara A. "Manipulation of sources and sinks of grasses : growth, photosynthesis and root exudation". Thesis, Bangor University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389504.
Pełny tekst źródłaRoworth, Joshua David. "The characterisation of root exudation and colonisation in the rhizosphere of land plants". Thesis, University of Oxford, 2017. http://ora.ox.ac.uk/objects/uuid:0f21602e-73c7-4470-a598-ec9f16093190.
Pełny tekst źródłaHolz, Maire [Verfasser], i Andrea [Akademischer Betreuer] Carminati. "Biophysical factors controlling root exudation and rhizosphere extension / Maire Holz ; Betreuer: Andrea Carminati". Bayreuth : Universität Bayreuth, 2020. http://d-nb.info/1209196565/34.
Pełny tekst źródłaMUELLER, KEVIN E. "INVESTIGATIONS INTO THE USE OF TREES FOR PHYTOREMEDIATION OF PAH CONTAMINATED SOILS". University of Cincinnati / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1123258067.
Pełny tekst źródłaRummel, Pauline Sophie [Verfasser]. "Nitrate uptake, root exudation, and litter quality - crop plant effects on denitrification and its product stoichiometry / Pauline Sophie Rummel". Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2021. http://d-nb.info/1236401689/34.
Pełny tekst źródłaDe, Lucchi Chiara. "Improving key root traits in sugar beet: Fusarium resistance". Doctoral thesis, Università degli studi di Padova, 2016. http://hdl.handle.net/11577/3424410.
Pełny tekst źródłaIl miglioramento genetico delle piante coltivate, basato sull’esplorazione, sull’utilizzo delle risorse genetiche e sulla ricerca genomica avanzata, è prioritario per soddisfare il fabbisogno alimentare di una popolazione mondiale in costante crescita. In particolare, l’introgressione di tratti desiderabili come la resistenza alle malattie e la maggior resa produttiva è fondamentale per garantire la sicurezza alimentare a livello globale. Per accelerare il miglioramento delle piante è essenziale predire le variazioni fenotipiche sviluppando marcatori molecolari legati ai tratti in esame. La selezione assistita da marcatori molecolari può ridurre costi e tempi di ottenimento di nuove varietà rispetto alla selezione basata solo su variazioni fenotipiche. Fra i marcatori molecolari disponibili, le mutazioni di singola base (SNP) sono i più diffusi. La barbabietola da zucchero (Beta vulgaris L.) è la seconda fonte di zucchero al mondo ed è coltivata in tutte le aree temperate. La coltura è colpita da numerosi patogeni e, fra questi, il fungo Fusarium oxysporum causa severi danni. Due differenti forme speciali di Fusarium, Fusarium oxysporum f. sp. betae (Fusarium yellows) e Fusarium oxysporum f. sp. radicis-betae (Fusarium root rot) sono state identificate in barbabietola. La malattia è caratterizzata da avvizzimento e clorosi fogliare con un progressivo deperimento delle foglie, spesso seguito dalla morte dell’intera pianta. I sintomi interni consistono in una discolorazione vascolare con imbrunimento dei fasci vascolari e, nel caso di marciume radicale, è presente un caratteristico annerimento all’esterno della radice principale. Per il controllo del patogeno, l’impiego di fungicidi e le rotazioni colturali non sono efficaci. L’introgressione di geni di resistenza dal germoplasma selvatico è ritenuta la strategia principale per la difesa della coltura. Questo richiede lo sviluppo di marcatori molecolari legati ai geni di resistenza per la selezione assistita degli individui resistenti. Gli obiettivi del lavoro di tesi sono stati i seguenti: (i) valutare la risposta a Fusarium oxysporum f. sp. betae di un’ampia collezione di linee di barbabietola da zucchero (ii) identificare linee resistenti a Fusarium oxysporum da poter utilizzare in futuri programmi di miglioramento genetico e (iii) identificare marcatori molecolari SNP (polimorfismi del DNA a singolo nucleotide) legati alla resistenza a Fusarium da utilizzare in programmi di selezione assistita da marcatori. Il primo contributo del lavoro di tesi descrive lo stato dell’arte dei risultati ottenuti nel miglioramento genetico della barbabietola da zucchero. Il contributo si focalizza sui progressi ottenuti nella resistenza a malattie con metodi di miglioramento genetici classico e con l’impiego di tecniche molecolari utilizzando come fonte di resistenza germoplasma selvatico. E’ stato inoltre considerato il contributo delle nuove tecnologie di sequenziamento e del recente rilascio del genoma di riferimento al miglioramento genetico della barbabietola. Il secondo contributo riguarda la valutazione della risposta a Fusarium oxysporum f. sp. betae di un’ampia collezione di linee di barbabietola da zucchero al fine di identificare linee resistenti e suscettibili. Per raggiungere questo scopo sono state esaminate 29 linee di barbabietola da zucchero. Le piante sono state infettate con due isolati fungini F19 e Fob220a, appartenenti a due gruppi genetici distinti, entrambi altamente patogenici. Dopo l’inoculo, per un periodo di sei settimane, è stato attribuito, per ciascuna pianta, un punteggio da 0 a 5 in base ai vari sintomi di malattia manifestati, quali: avvizzimento fogliare, clorosi e necrosi. Successivamente, le piante sono state raccolte e le radici sono state esaminate per vedere dove era presente marciume radicale, discolorazione e quali piante invece risultavano resistenti al patogeno. Il terzo contributo descrive la risposta di due diverse collezioni di germoplasma di barbabietola da zucchero a isolati di Fusarium oxysporum f. sp. betae. Linee suscettibili, provenienti da USDA-ARS (US) e UNIPD (Università di Padova, Italia), sono state inoculate con tre distinti isolati di Fusarium oxysporum f. sp. betae, l’agente causa di Fusarium yellows. Tutte le linee inoculate hanno sviluppato i sintomi della malattia, ma un grave marciume radicale è stato osservato solo nelle linee provenienti da UNIPD inoculate con isolati che non avevano mai causato marciume radicale nel germoplasma USDA. Il quarto contributo riguarda l’identificazione, su geni candidati, di marcatori molecolari SNPs associati alla resistenza alla malattia. In particolare, sono stati identificati 5 analoghi a geni di resistenza (RGA) dal lavoro di Dohm et al. 2014 e sono stati analizzati tramite analisi High Resolution Melting (HRM) su 96 campioni delle 6 linee più resistenti e più suscettibili a Fusarium. Due varianti, in 2 dei geni testati, sono risultate significativamente associate (p < 0.01) con la resistenza a Fusarium. Le varianti sono state validate attraverso sequenziamento Sanger. Il sequenziamento ha permesso di individuare due marcatori SNPs. L’associazione tra questi due SNPs e la resistenza a Fusarium è stata successivamente validata con il metodo di genotipizzazione Comparative allele-specific PCR (KASPar) su 96 campioni resistenti e 96 campioni suscettibili. La frequenza dell’allele A sia per lo SNP_Bv7_171470 e lo SNP_Bv2_043450 è risultata significativamente più alta negli individui resistenti rispetto a quelli suscettibili. Questi due SNPs potranno essere utilizzati in programmi di selezione genetica al fine di migliorare la resistenza a Fusarium in barbabietola da zucchero.
Scott, Gavin D. "Root system traits and root longevities in two contrasting cultivars of Trifolium repens (White clover)". Thesis, University of Aberdeen, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.425002.
Pełny tekst źródłaPatel, Dhaval V. "Dissecting natural variation of root traits in arabidopsis thaliana accessions". Thesis, University of Nottingham, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.503910.
Pełny tekst źródłaHeras, Ambros Paloma. "Barley root traits for improved subsoil exploration and resource capture". Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/43532/.
Pełny tekst źródłaGougherty, Steven W. "Exudation Rates and δ13C Signatures of Bottomland Tree Root Soluble Organic Carbon: Relationships to Plant and Environmental Characteristics". The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1448818110.
Pełny tekst źródłaBergmann, Joana [Verfasser]. "Root traits and their effect in plant-soil interactions / Joana Bergmann". Berlin : Freie Universität Berlin, 2018. http://d-nb.info/1159900531/34.
Pełny tekst źródłaGriffiths, Marcus. "Identifying wheat root traits and regulatory genes for nitrogen uptake efficiency". Thesis, University of Nottingham, 2018. http://eprints.nottingham.ac.uk/48611/.
Pełny tekst źródłaValverde-Barrantes, Oscar Jesus. "A phylogenetic perspective on fine root ecology: assessing the role of root evolution on fine root functional traits and ecological interactions in woody angiosperms". Kent State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=kent1384641579.
Pełny tekst źródłaNazemi, Ghasemali <1976>. "Genetic basis of variation for root traits and response to heat stress in durum wheat". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amsdottorato.unibo.it/7166/1/nazemi_ghasemali_tesi.pdf.
Pełny tekst źródłaNazemi, Ghasemali <1976>. "Genetic basis of variation for root traits and response to heat stress in durum wheat". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amsdottorato.unibo.it/7166/.
Pełny tekst źródłaPogiatzis, Antreas. "Comparative response of six grapevine rootstocks to inoculation with arbuscular mycorrhizal fungi based on root traits". Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/61809.
Pełny tekst źródłaIrving K. Barber School of Arts and Sciences (Okanagan)
Biology, Department of (Okanagan)
Graduate
Yang, Luojin [Verfasser], Klaus [Akademischer Betreuer] [Gutachter] Dittert, Petr [Gutachter] Karlovsky i Andrea [Gutachter] Carminati. "Root exudation pattern of sugar beet (Beta vulgaris L.) as influenced by light intensity and P deficiency / Luojin Yang. Betreuer: Klaus Dittert. Gutachter: Klaus Dittert ; Petr Karlovsky ; Andrea Carminati". Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2016. http://d-nb.info/1109046499/34.
Pełny tekst źródłaFrost, Aaron Desmond James, i n/a. "The Reciprocal Relationship Between Conduct Problems, Callous Unemotional Traits, and Parenting Behaviour". Griffith University. School of Psychology, 2006. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20070109.094343.
Pełny tekst źródłaKiran, Aysha [Verfasser]. "Genetic and phenotypic analysis of complex seed and root traits in oilseed rape (Brassica napus L.) / Aysha Kiran". Gießen : Universitätsbibliothek, 2015. http://d-nb.info/1068874821/34.
Pełny tekst źródłaHerz, Katharina [Verfasser]. "Drivers of intraspecific variation of plant functional traits, plant performance and root exudates in German grasslands / Katharina Herz". Halle, 2017. http://d-nb.info/1142155315/34.
Pełny tekst źródłaThomas, C. L. "High throughput phenotyping of root and shoot traits in Brassica to identify novel genetic loci for improved crop nutrition". Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/43440/.
Pełny tekst źródłaRadanielson, Mariot Ando. "Identification de nouveaux traits de sélection pour améliorer la productivité en situation de déficit hydrique chez le tournesol". Thesis, Montpellier, SupAgro, 2011. http://www.theses.fr/2011NSAM0013/document.
Pełny tekst źródłaThis work was an attempt to assist sunflower breeding program by crop physiology knowledge to sustain and to improve productivity under water deficit. The approach was based on using SUNFLO-CLIMATOR, a biophysical crop modelling to identify the limiting factors to plant productivity. These factors were considered as potential new traits for breeding program. Their assessment for this objective corresponded to four criteria: genotypic variability, impact on plant productivity, heritability and simplified phenotyping method. Thus, traits related to genotypic parameters of three processes were analysed: phenology, architecture and soil water uptake. Their variability was evaluated on field and greenhouse experiments carried out with 19 inbred lines and 125 hybrids. Sensitivity analysis of plant yield, simulated with SUNFLO-CLIMATOR model, was then done to estimate the impact of the parameter variability among the studied genotypes. Quantitative genetic analyses were used to evaluate their heritability and the combining ability of the parental inbred lines.Large phenotypic variability was observed for each parameter with a significant “genotype” effect. Thermal time for flowering displayed high heritability about H² = 0.78. Thermal time to physiological maturity (M3) displayed high environmental effect on its variability. Its genotypic variability would probably need new way of modelling such as the development of a seed growth module. Architectural traits related to canopy size and shape presented also lower heritability (0.20 ≤ H² ≤ 0.39) and their impact on plant productivity depends on their interaction. However the trait position of the largest leaf A2gen and its leaf area A3gen could be yet used to screen the best inbred lines for improving radiation interception efficiency of the hybrids during the grain-filling phase.Root depth is a relevant trait for deeper soil. Its access remains difficult and time consuming. For shallower or medium depth soil, higher water extraction capacity seemed allow higher plant yield with linear relationship about 0.8 – 1.5 q ha-1 more per 1% decrease of soil water content minimal for water extraction. The index of water extraction (IEgen) displayed high value of heritability (0.77 ≤ H² ≤ 0.83). The genotypic parameters A2gen, A3gen, IEgen were confirmed with genetic resources to enhance plant productivity under water deficit. Research for their molecular marker would be a next step for this work and an issue for a new selection assisted by marker molecular and plant modelling
Mgbeahuruike, Anthony Christian. "A study of the traits associated with the biocontrol activity of Phlebiopsis gigantea /". Uppsala : Dept. of Forest Mycology and Pathology, Swedish University of Agricultural Sciences, 2009. http://epsilon.slu.se/11605615.pdf.
Pełny tekst źródłaHecht, Vera Lisa [Verfasser]. "Root and shoot phenotypic traits and their expression in response to sowing density in spring barley (Hordeum vulgare) / Vera Lisa Hecht". Bonn : Universitäts- und Landesbibliothek Bonn, 2019. http://d-nb.info/1221669427/34.
Pełny tekst źródłaSharma, Sundrish. "Characterization of quantitative loci for morphological and anatomical root traits on the short arm of chromosome 1 of rye in bread wheat". Diss., [Riverside, Calif.] : University of California, Riverside, 2009. http://proquest.umi.com/pqdweb?index=0&did=1899491951&SrchMode=2&sid=1&Fmt=2&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1269025605&clientId=48051.
Pełny tekst źródłaIncludes abstract. Title from first page of PDF file (viewed March 18, 2010). Includes bibliographical references. Issued in print and online. Available via ProQuest Digital Dissertations.
Bakhshandeh, Shiva. "Effect of Climate Change and Soil Management on Water and Nutrient Uptake for Sustainable Yield of Wheat Genotypes with Different Root Traits". Thesis, The University of Sydney, 2018. http://hdl.handle.net/2123/18649.
Pełny tekst źródłaZamora-Ledezma, Ezequiel. "Evidences for an indirect effect of root functional traits and plant composition on soil microbial activities in Mediterranean rangelands : a spatial and temporal approach". Thesis, Montpellier 2, 2013. http://www.theses.fr/2013MON20176/document.
Pełny tekst źródłaIt is increasingly recognized that the understanding of ecosystem functioning requires a combined above- and belowground approach, because of the importance of feedbacks between plants and soil. Plant community structure may affect soil functioning by altering the quantity and the quality of resources entering the soil. Abiotic controls on soil microbial processes are well documented, but potential effects of plant composition and root traits are poorly understood. The study was conducted in Mediterranean grasslands located in southern France. We selected 12 contrasting communities along a gradient of soil resource availability, which is mainly driven by soil texture. The aims of the thesis were to evaluate: i) the response of plant composition and leaf and root traits measured at the community level along the soil gradient and across seasons, ii) their effect on three soil microbial processes involved in carbon (C) and nitrogen (N) cycling, i.e. substrate-induced respiration (SIR), nitrifying (NEA) and denitrifying enzyme activities (DEA). In sandy soils (unproductive plots) plant communities had a conservation strategy at the leaf level and an acquisitive strategy at the root level suggesting a strong plasticity of root traits in response to resource limitation; rates of SIR and NEA were higher. Opposite pattern was observed in clay productive soils. DEA did not vary along the gradient. We did not find evidence of a species richness, evenness, or plant biomass effect on SIR and NEA. However, we demonstrated that they were strongly influenced by plant functional composition (abundance of graminoids), and particularly by root traits. Our most innovative finding evidences that NEA, and to a lesser extent SIR, were positively correlated with root nitrogen (N) concentration and negatively correlated with C/Ncom, whereas analogous leaf traits have only minor effect on microbial activities. Our results suggested that the chemical quality of roots is the main driver of soil activities and this was confirmed across the seasons. We highlight strong seasonal variations in plant community composition, root traits and soil microbial activity, except DEA. Seasonal variations in root traits were interpreted as a relative change in the proportion of young versus old roots and suggested an asynchrony between above– and belowground growth. We showed for the first time evidences that in natural conditions, seasonal changes in root functional traits could be implicated in driving NEA and SIR. This result demonstrates the need to further develop studies allowing a better understanding of the role of root traits as soil functioning drivers
Thosago, Setshele Standford. "Response of selected cowpea lines to low soil phosphorus and moisture stress conditions at Ukulima Farm in Limpopo Province". Thesis, University of Limpopo, 2015. http://hdl.handle.net/10386/1585.
Pełny tekst źródłaCowpea (Vigna unguiculata L. Walp) is an important grain legume grown in many parts of the world mostly by smallholder (SH) farmers. Low soil phosphorus (P) and drought stress are major constraints to legume production and threaten food security. Root architecture is a spatial configuration of the root system which is influenced by moisture status and P uptake. A field experiment was conducted at Ukulima farm near Modimolle in Waterberg district during 2012/13 summer growing season. The treatments comprised of two levels each for soil P (low and high) and moisture status (water stress and well-watered); and eight cowpea genotypes (Tvu 4632, Tvu 6365, Tvu 9848, Tvu 15445, Tvu 16408, Tvu 15143, Oloyin and IT00K-1217). The low P level implied the available P in the soil measured in situ, which was less than 8 mg kg-1 while the high P level entailed fertilization at the rate of 40 kg P ha-1 application to achieve approximately 35 mg P kg-1 of soil . The root traits measured included angle of adventitious and basal roots, number of basal roots, tap root diameters at 5, 10, 15 and 20 cm soil depths; lateral branching densities at depth 5,10 and 15 cm, nodule score, deep score, shallowness score, 3rd order branching density, and 1.5 branching densities at 5 and 10 cm depth. Plant parameters measured were plant height, number of pods per plant, number of seeds per pod, length of the pods, unshelled weight, shelled weight and number of primary and secondary branches. Photosynthetic parameters measured were photosynthetic rate, intercellular CO2 concentration, water conductance, transpiration rate, vapour pressure deficits, sample cell CO2, sample cell H2O and relative humidity in the cell. All treatment factors were combined as split-split plot arrangement fitted into randomized complete block design; with four replicates. Results indicate that the lateral root branching density at 5 and 10 cm differed significantly (P≤0.05) across cowpea genotypes. Genotype showed significant effect on taproot diameter at 10 cm. Moisture status and P level exerted significant effect on cowpea genotypes 15 cm. There were significant differences (P≤0.05) for lateral root branching density observed at 5 and 10 cm depth in P rates x genotype interaction. Statistical analysis showed that P levels and cowpea genotypes had significant effects (P≤0.05) on mean plant height, biomass and highly significantly effects (P≤0.01) on number of branches, days to physiological maturity and mean pod length. The interaction between cowpea genotype and moisture stress condition significantly (P≤0.05) affected hundred (100) seed weight. Cowpea genotype Tvu16408 obtained highest grain yield of 3240 kg ha-1 and lowest was by IT00K1217 which obtained grain yield of 1256 kg ha-1. Results showed that photosynthetic rate, water conductance, transpiration rate, sample cell CO2, sample cell H2O, relative humidity in the cell, intercellular CO2 and vapour pressure deficit differed significantly (P≤0.05) across cowpea genotypes. Soil moisture condition and cowpea genotype exerted significant (P≤0.01) effect on photosynthetic rate, water conductance, transpiration rate, sample cell CO2, sample cell H2O and relative humidity in the cell. Variation in P levels had no significant effect on the measured photosynthetic parameters. Oloyin genotype had the highest photosynthetic rate followed by Tvu 4632 while cowpea genotype Tvu 9848 had the least photosynthetic rate. Interaction of moisture stress and cowpea genotype had a significant effect on intercellular CO2 concentration. Water stress reduced the intercellular CO2 concentration of Oloyin, Tvu 6365 and 4632 but resulted in a significant increase in intercellular CO2 concentration in Tvu 9848 genotype. Results showed that variation in soil P level exerted a significant (P≤0.05) effect on grain tissue P content and uptake, and a highly significant (P≤0.01) difference in P content across the various cowpea genotypes. Moisture stress exerted a significant (P≤0.05) difference on P uptake. The results showed that P levels and cowpea genotype variation exerted significant (P≤0.05) effects on P content, P uptake and nitrogen (N) uptake. Moisture status and cowpea genotype variation exerted significant (P≤0.05) effects on total N and N uptake. Cowpea genotype Tvu 9848 obtained more total N content (4.37%), while the lowest total N content was obtained by cowpea genotype Tvu 15445 with 3035 mg kg-1. The interaction between cowpea genotype and moisture status exerted a significant (P≤0.05) effect on N and P uptake of immature green pods harvested. There is a need to conduct more studies to identify cowpea genotypes, their root architecture and agronomic measures that can do well under xvii drought stress and low soil P conditions. Research needs to be conducted to enhance cowpea productivity under both low soil P and drought stress. Keywords: cowpea genotypes; moisture stress; phosphorus fertilisation; root traits
Romillac, Nicolas. "Effets de l’introduction du pois dans une succession de cultures sur certaines communautés végétales et bactériennes et leurs fonctions écosystémiques associées". Thesis, Université de Lorraine, 2015. http://www.theses.fr/2015LORR0266/document.
Pełny tekst źródłaCrops species modify resources availability and perturbation regimes perceived by the communities of organisms residing in the agroecosystems and, as a consequence, can lead to alteration of ecosystem functions useful to crop production, such as nitrogen and sulfur mineralization or crop-weeds competition, realized by weeds or microorganisms. Our objective was to study the effect of a legume, pea, when introduced in a crop succession, on weed communities and microbial communities involved in protein decomposition and sulfate ester mineralization, which are the main forms of N and S, respectively, in agricultural soils. To do so, we performed experiments in controlled conditions used data from a 5-years field experiment. In controlled conditions, we showed that pea during its development modify through its root functional traits several enzymatic activities involved in N decomposition/mineralization. However, in the field experiment, climatic factors were the main drivers of the microbial communities involved in N and S decomposition/mineralization. Moreover, pea selected weed communities that were functionally different from weed communities growing in other crops such as oilseed rape. However, this effect did not persist under the following crop. As a conclusion, our results suggest that pea modifications of microbial communities are weak compared to other factors such as climatic factors. However, pea effects on weed communities are strong but short lived. Those results highlight the complementarity of microcosm and field experiments, and the necessity of long term field experiments to take into account climate variability
Sayed, Mohammed Abd El-Aziz Abd El-Haliem [Verfasser]. "QTL Analysis for Drought Tolerance Related to Root and Shoot Traits in Barley (Hordeum vulgare L.) / Mohammed Abd El-Aziz Abd El-Haliem Sayed". Bonn : Universitäts- und Landesbibliothek Bonn, 2011. http://d-nb.info/101624875X/34.
Pełny tekst źródłaFort, Florian. "Stratégies d’acquisition des ressources des plantes prairiales sous contraintes hydrique et minérale - Rôle du système racinaire dans la réponse aux facteurs structurant les communautés". Phd thesis, Toulouse, INPT, 2013. http://oatao.univ-toulouse.fr/10428/1/Fort.pdf.
Pełny tekst źródłaGroleau-Renaud, Virginie. "Contrainte mécanique et exsudation racinaire du maïs : incidence de la morphologie du système racinaire". Vandoeuvre-les-Nancy, INPL, 1998. http://docnum.univ-lorraine.fr/public/INPL_T_1998_GROLEAU_RENAUD_V.pdf.
Pełny tekst źródłaBeyer, Friderike Verfasser], Christoph [Akademischer Betreuer] Leuschner i Dirk [Akademischer Betreuer] [Hölscher. "Fine root traits, belowground interactions and competition effects on the rhizosphere of Fagus sylvatica and Fraxinus excelsior saplings / Friderike Beyer. Gutachter: Christoph Leuschner ; Dirk Hölscher. Betreuer: Christoph Leuschner". Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2013. http://d-nb.info/104430622X/34.
Pełny tekst źródłaHunter, Kirsten, i n/a. "Affective Empathy in Children: Measurement and Correlates". Griffith University. School of Applied Psychology, 2004. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20040610.135822.
Pełny tekst źródłaGhestem, 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.
Pełny tekst źródłaGrimal, Jean-Yves. "Influence de l'exsudation racinaire de Zea mays L. Sur mobilisation de formes de phosphore difficilement biodisponibles". Vandoeuvre-les-Nancy, INPL, 1994. http://www.theses.fr/1994INPL058N.
Pełny tekst źródłaTremblay-Boeuf, Valérie. "Effets des contraintes mécaniques sur l'exsudation racinaire du maïs". Vandoeuvre-les-Nancy, INPL, 1995. http://www.theses.fr/1995INPL079N.
Pełny tekst źródłaAndrade, Bianca Ott. "Interação solo-vegetação campestre:estudos de caso em diferentes escalas ecológicas". reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2014. http://hdl.handle.net/10183/148772.
Pełny tekst źródłaWhereas in temperate regions the abiotic-biotic relationship is well-known, in the tropics and subtropics our understanding is still preliminary. There is an urgent need to determine abiotic factors that control vegetation patterns in order to give support to restoration and conservation approaches. The present thesis analyses the relationship between abiotic factors and grassland vegetation in three original research papers (chapters I, II and III) and a review paper (chapter IV). In the first three papers, vegetation variance in response to abiotic factors was analyzed at different ecological scales; and in the fourth, the variance in biotic and abiotic factors in response to degradation process was discussed with a more applied view. Thus in this thesis the aim is to answer the following questions: (I) Which differences can be found in functional plant traits and allocation strategies within species at different levels of water and nutrient availability?; (II) How variable are physical and chemical parameters in different spatial scales; and are there soil parameters that can more accurately explain plant distribution in different spatial scales? (III) How much of RS grassland vegetation variance can be explained by soil and climatic properties; and which climatic and soil properties better explain these vegetation patterns? In chapter IV a conceptual model of grassland degradation is presented and applied to Rio Grande do Sul (RS) grasslands. To address these questions I used species-level data in a calcareous grassland in Germany (chapter I); community-level data in six sites in RS, South Brazilian grasslands (chapter II and III); and a review of literature studies concerning RS grassland degradation and restorability (chapter IV). The results showed that: (I) at a intraspecific level, the study species showed two allocation strategies in relation to resource stress, while the responses of individual traits to the soil treatments were consistent across species; (II) soil parameters variation are related to the measurement scale applied and the vegetation variance often responds to different soil parameters at different scales; (III) climatic and soil properties explained 45% of vegetation variance between biomes in RS grasslands and the main factors controlling its variance are annual precipitation and percent aluminum saturation; and (IV) the conceptual model is displayed as biotic and abiotic changes along the axes and can serve as a general framework to study degradation and restorability of tropical and subtropical grasslands, and further it may facilitate decisions on alternative management and conservation. As a general conclusion, the grassland vegetation responds to changes in the environment in different scales and may use different strategies to overcome environmental selective forces and degradation process. The understanding of this relationship is of high importance to facilitate decisions on alternative management and conservation.
Demenois, Julien. "Quelle influence des symbioses mycorhiziennes et des traits racinaires sur l'érosion des sols tropicaux ? Application à la restauration écologique des écosystèmes forestiers dégradés de Nouvelle-Calédonie sur Ferralsols développés sur substrats ultramafiques". Thesis, Paris, AgroParisTech, 2017. http://www.theses.fr/2017AGPT0011.
Pełny tekst źródłaTropical forest ecosystems cover nearly half of the world's forest area. These ecosystems provide basic services for the well-being of our societies (e.g. regulation of material flows, soil preservation) are particularly affected (loss and degradation of forests) by global changes. New Caledonia, and its ultramafic substrates, is no exception to this trend. Mining and fires are responsible for forest regression, fragmentation, degradation and soil erosion. The archipelago is ranked among the hotspots of global biodiversity and the ecological restoration of these ecosystems is a major challenge. The objective of this thesis is to contribute to the ecological restoration of the forests of New Caledonia in order to limit the erosion of soils on ultramafic substrates and is part of the disciplinary field of the ecology of restoration. The scientific objective is to study the influence of mycorrhizal symbiosis and root traits on the erosion of Ferralsols developed on ultramafic substrates through a multi-scale approach. In the first part, we highlight the floristic and structural characteristics of plant communities on ultramafic substrates. These suggest an increased expression of the root traits of dominant species in monodominant forests. The central place of fire and cyclones in the dynamics of plant succession is also emphasized, as well as mycorrhizal symbioses in maintaining the monodominance of Nothofagus aequilateralis. In the second part, our work suggests the existence of a biotic threshold between degraded ligno-herbaceous maquis and ligno-herbaceous maquis. Repeated fires would be the main cause of crossing this threshold. The increase in plant biomass would be the key factor contributing to the stability of the aggregates between these two stages. Thus, fire protection combined with the promotion of plant successions through the use of potentially facilitating species such as Costularia arundinacea could be an efficient strategy for limiting erosion of Ferralsols. In addition, the influence of plant (e.g. floristic composition) and fungal communities (e.g. biomass) on the stability of aggregates is clearly highlighted. The third part aims to evaluate the ability of plant species, combined with mycorrhizal fungi, to increase the stability of aggregates, but also to identify root traits and mycorrhizal associations contributing to this increase. In this section, we demonstrate that the combination of high values for “Root Mass Density - Root Length Density – percentage of fine roots” is effective in increasing aggregate stability. Moreover, the efficacy of this combination of root traits is enhanced by mycorrhizal symbiosis. Thus, of the three plant species evaluated, Costularia arundinacea would be the most effective tool species for increasing the stability of aggregates. This work allowed us to highlight the influence of root traits and mycorrhizal symbiosis on the stability of soil aggregates on Ferralsols on ultramafic substrates, at the scale of plant communities or at the level of plant species. To our knowledge, these results are the first to be acquired on this type of soil. These results make it possible to formulate proposals for the ecological restoration of forest ecosystems in New Caledonia in order to limit soil erosion on ultramafic substrates, but also to sketch new avenues of research
Polania, Perdomo José A. "Morpho-physiological analysis of adaptive responses of common bean (Phaseolus vulgaris L.) to drought stress". Doctoral thesis, Universitat Autònoma de Barcelona, 2016. http://hdl.handle.net/10803/400243.
Pełny tekst źródłaCommon bean (Phaseolus vulgaris L.) is the most important food legume in the diet of poor people in the tropics. This legume is cultivated by small farmers and is usually exposed to unfavorable conditions with minimum use of inputs. Drought and low soil fertility, especially phosphorus (P) and nitrogen (N) deficiencies, are major limitations to bean yield in smallholder systems. Beans can derive part of their required N from the atmosphere through symbiotic nitrogen fixation (SNF). Drought stress severely limits SNF ability of plants. Identification of traits associated with drought resistance contributes to improving the process of designing bean genotypes adapted to these conditions. Field studies were conducted at the International Center for Tropical Agriculture (CIAT), Palmira, Colombia to determine the relationship between grain yield and different parameters in elite lines selected for drought resistance over the past decade. The selected traits were effective use of water (EUW), canopy biomass, remobilization of photosynthates to grain (pod partitioning index, harvest index and pod harvest index) and SNF ability. Moreover, in field trials we also validated the use of 15N natural abundance in grain tissue to quantify phenotypic differences in SNF ability for its implementation in breeding programs aiming to improve SNF in common bean. Carbon isotope discrimination (CID) was used for estimation of water use efficiency (WUE) and effective use of water (EUW). A set of 36 bean genotypes belonging to the Middle American gene pool were evaluated under field conditions with two levels of water supply (irrigated and rainfed) over two seasons. Additionally, a greenhouse study was conducted at CIAT using plastic cylinders with soil inserted into PVC pipes, to determine the relationship between grain yield and different root parameters such as total root length, fine root production and visual root growth rate in same group of elite lines under drought stress. Resistance to terminal drought stress was positively associated with EUW combined with a deeper and vigorous root system, better plant growth, and superior mobilization of photosynthates to pod and seed production, but negatively associated with days to flowering and days to physiological maturity. Based on phenotypic differences in CID, leaf stomatal conductance, canopy biomass and grain yield under drought stress, the tested lines were classified into two groups, water savers and water spenders. These groups also differ in their root characteristics, water spenders with a vigorous and deeper root system and water savers genotypes with a moderate to shallow root system and more presence of fine roots. We used 15N natural abundance method to compare SNF ability estimated from shoot tissue sampled at mid-pod filling growth stage vs. grain tissue sampled at harvest. The results showed a significant positive correlation between nitrogen derived from the atmosphere (Ndfa), estimated using shoot tissue at mid-pod filling, and Ndfa estimated using grain tissue at harvest. The method showed phenotypic variability in SNF ability under both drought and irrigated conditions. A significant reduction in SNF ability was observed under drought stress. We suggest that the method of estimating Ndfa using grain tissue (Ndfa-G) can be applied in bean breeding programs to improve SNF ability. Using this method of Ndfa-G, we identified bean lines that combine greater SNF ability with higher grain yield under drought stress. Better SNF ability under drought stress was related with superior presence of thick roots. Superior N uptake from the soil was associated with a large root system with more presence of fine roots. Pod harvest index, grain CID and Ndfa using grain tissue could be a useful selection criterion in breeding programs to select for drought resistance in common bean.
Zwicke, Marine. "Impacts d'une canicule sécheresse sur le fonctionnement et la structure des communautés végétales de l'écosystème prairial". Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2013. http://tel.archives-ouvertes.fr/tel-01020033.
Pełny tekst źródłaRossi, Lorenzo Matteo Walter. "Embankment as a carbon sink : a study on carbon sequestration pathways and mechanisms in topsoil and exposed subsoil". Thesis, Montpellier, 2019. http://www.theses.fr/2019MONTG083.
Pełny tekst źródłaCarbon (C) sequestration is receiving increasing scientific and political attention in a framework of greenhouse gasses mitigation. However, geotechnical soils have been neglected for their C sequestration potential, with the global attention focusing on agricultural and natural soils. In the present thesis project we aim to assess the potential of geotechnical embankments as C sink, and, through the study of plant species and soils showing contrasting features, shed light on SOC sequestration mechanisms and the role of the different actor involved. We aim not only to quantify the C gained and lost in soil, but even its origin (fresh new C input or old preexistent C) and how it is partitioned in different C pools characterized by different C stability (quality of stored C). First, we evaluated the C storage in different pools under soil sowed with 12 different herbaceous species in a 10 months experiment. Assessing different root traits allowed understanding the influence of root economic spectrum on C storage. We showed how traits linked to high labile C are linked to a higher C increase in the stable SILT+CLAY pool (<20µm). Root traits related to a low input of recalcitrant, instead, favor accumulation in the unstable POM fraction. Thanks to a 183 days stable isotope labelling experiment (CO2 constantly enriched with 13C) we were able to study the C dynamics in different C pools under two species (L. perenne and M. sativa) sowed on two soil (topsoil, 0-30cm depth and subsoil brought to the surface, 110-140 cm depth) showing contrasting characteristics. We evidenced the great interest of bridging C origin and C pools when studying soil C fates, allowing unveiling processes those more traditional methods would hide. New C and old C showed synergetic covariation, with lower old C losses associated to higher new C inputs. This is in good accordance with the Preferential Substrate Utilization hypothesis (Cheng and Kuzyakov, 2005). The Preferential Substrate Utilization hypothesis was also validated with the study of priming effect and soil respiration, that showed higher plant derived C in respired CO2 when plant C input were high, while increasing old C mineralization when plant C input were low, i.e. in subsoil. We observed significant plant derived new C input in the SILT+CLAY fraction (<20µm, highly stable) supporting evidence of the in vivo entombing effect in the soil Microbial Carbon Pump hypothesis (Liang et al., 2017). The species effect mainly occurred on new C input, but it was overpowered by the soil effect, with lower C storage in low quality soil (low nitrogen and microbial biomass and activity). In general, microbiological conditions were the main driver for new C accumulation and old C loss, and helped to explain why no effect of soil C saturation – a central theory in recent studies on C sequestration - was find in the protected carbon. Such fundamental understanding of plant-soil interactions help us to better optimize soil and vegetation management for road embankment revegetation
Leyval, Corinne. "Intéractions bactéries-mycorhizes dans la rhizosphère du pin sylvestre et du hêtre : Incidences sur l'exsudation racinaire et l'altération des minéraux". Nancy 1, 1988. http://www.theses.fr/1988NAN10169.
Pełny tekst źródłaYang, Luojin. "Root exudation pattern of sugar beet (Beta vulgaris L.) as influenced by light intensity and P deficiency". Thesis, 2016. http://hdl.handle.net/11858/00-1735-0000-0028-87DC-8.
Pełny tekst źródłaHenry, Amelia Lynch Jonathan P. "Root traits for sustainable low-input agro-ecosystems". 2008. http://etda.libraries.psu.edu/theses/approved/WorldWideIndex/ETD-2974/index.html.
Pełny tekst źródłaHagerty, Christina H. "Mapping QTL for root rot resistance, root traits, and morphological trait in a common bean recombinant inbred population". Thesis, 2013. http://hdl.handle.net/1957/38263.
Pełny tekst źródłaGraduation date: 2013
Han, Tsung-Han, i 韓宗翰. "Developing A System for Quantifying Root Traits of Rice Seedlings in 3D". Thesis, 2017. http://ndltd.ncl.edu.tw/handle/x5mne5.
Pełny tekst źródła國立臺灣大學
生物產業機電工程學研究所
105
Roots are important organs of plants. Root system architecture (RSA), the spatial configuration of roots, of rice (Oryza sativa L.) has shown a high degree of diversity. RSA needs to be quantified with high accuracy to understand the relationship between RSA and functionality of rice roots. This study developed a three-dimensional (3D) imaging system to quantify the RSA of rice seedling roots of 15 varieties. In this work, rice seedlings were cultivated in glass tubes filled with transparent jelly culture medium for ten days. The two-dimensional (2D) side-view images of the seedlings were acquired using the imaging system. Silhouettes of rice roots were then identified from the 2D side-view images using image recognition technology. Three-dimensional images of the rice roots were next reconstructed using the silhouettes and space-carving algorithm. A ground truth was used to validate the accuracy of the system. Last, RSA traits of rice seedling root of 15 varieties were quantified.
Lin, Shih-Hung, i 林士弘. "Quantitative trait loci mapping for rice root traits under salinity stress at seedling stage". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/71038137113645207736.
Pełny tekst źródła國立臺灣大學
農藝學研究所
102
Rice is one of the major crops in the world. Because human population grows, increasing rice production is necessary to meet human’s need. Salinity is a common abiotic stress to affect crop production, and rice is one of salt sensitive crops, therefore maintaining rice growth vigor under salt condition is an important issue. Root system is a major physical interaction between plants and soil substrates, it affects nutrients and salt absorption. In this research, we used two populations as study materials, one is recombinant inbred lines population derived from a cross between indica and temperate japonica, and a global diversity panel with 196 accessions. We measured root length under normal and salt condition at seedling stage, and found out degree of root growth vigor inhibited by salinity stress differs by root types. We used high density SNP markers to map QTLs controlling shoot and root growth in response to salt stress, many QTLs in RILs and in global diversity panel were mapped in this study. Although there was positive correlation between root and shoot traits under salinity stress, no identical QTLs were mapped. We selected accessions with good performance under salinity stress, these accessions will be good breeding materials to improve root vigor in elite cultivars, and through molecular assisted selection, QTLs with positive effect can be introduced to elite cultivars efficiently.