Dissertations / Theses on the topic 'Plant abiotic stresses'
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Karim, Sazzad. "Exploring plant tolerance to biotic and abiotic stresses /." Uppsala : Dept. of Plant Biology and Forest Genetics, Swedish University of Agricultural Sciences, 2007. http://epsilon.slu.se/200758.pdf.
Full textSingh, Shardendu Kumar. "DEVELOPING SCREENING TOOLS FOR ABIOTIC STRESSES USING COWPEA [VIGNA UNGUICULATA (L.) WALP.] AS A MODEL CROP." MSSTATE, 2008. http://sun.library.msstate.edu/ETD-db/theses/available/etd-09032008-105843/.
Full textCavaliere, Chiara. "Studies of plant proteomics and metabolomics by means of multidimensional analytical techniques." Doctoral thesis, La Sapienza, 2007. http://hdl.handle.net/11573/916872.
Full textCorso, Massimiliano. "A transcriptomic approach to dissect the effect of grapevine rootstocks on plant tolerance to abiotic stresses and berry ripening." Doctoral thesis, Università degli studi di Padova, 2014. http://hdl.handle.net/11577/3423558.
Full textLa vite (genere Vitis) rappresenta una delle principali specie coltivate su scala mondiale , con una produzione che si avvicina ai 70 milioni di tonnellate e una superficie coltivata di oltre 7 milioni di ettari . Tra le 60 specie all'interno del genere Vitis, Vitis vinifera L. è la più utilizzata per la produzione di vino e distillati. Prima della devastazione della viticoltura europea causata dall'introduzione del parassita fillossera dal Nord America, le varietà di V. vinifera usate per la produzione di vino in Europa non erano innestate. Successivamente, l'utilizzo di portinnesti di origine americana ha permesso di fornire una maggiore resistenza al parassita e ad altre malattie che stavano seriamente compromettendo la viticolture Europea. I portinnesti più usati commercialmente derivano da incroci di svariate specie di vite, tra cui V. berlandieri, V. riparia e V. rupestris, e, oltre a migliorare la resistenza alla fillossera e altri patogeni, conferiscono caratteristiche di tolleranza a stress abiotici (come siccità, elevata salinità e Fe-carenza), regolano la crescita dell’acino, contribuiscono alla maturazione e alla qualità dei frutti, possono alterare alcuni aspetti legati alla qualità in post-raccolta dell’acino. I risultati presentati in questa tesi di dottorato sono parte integrante di un progetto multi- disciplinare chiamato SERRES (selezione di nuovi portinnesti di vite resistenti a stress abiotici attraverso lo sviluppo e la validazione di marcatori molecolari) e finanziato dalla fondazione Ager. La selezione e la caratterizzazione di portainnesti che conferiscano un maggiore grado di tolleranza agli stress abiotici è essenziale per lo sviluppo di modelli agricoli sostenibili e, allo stesso tempo, per l’induzione di un rapporto equilibrato tra fase vegetativa e produttiva, una progressione diversa della maturazione dell’uva, così come, differenze a livello qualitativo. Migliorare la conoscenza delle basi molecolari, biochimiche e fisiologiche della resistenza allo stress è un requisito fondamentale per la selezione di genotipi in grado di far fronte alle condizioni di stress senza conseguenze negative su crescita vegetativa e produzione di uva ad alta qualità. Lo stress idrico ha un impatto enorme sulla produzione agricola, infatti, è uno dei principali fattori che limitano la produttività delle piante e causano una grave riduzione della resa. Sulla base dei modelli climatici globali, che prevedono un aumento delle aree aride nel prossimo futuro, la carenza idrica può diventare il principale fattore limitante per la coltivazione. In questo contesto, i portinnesti potrebbero assumere un ruolo importante nel limitare la perdita di raccolto migliorando l'efficienza dell'uso dell'acqua, il potenziale di sopravvivenza della pianta e la capacità di crescita del frutto in presenza di condizioni avverse come siccità ed elevata salinità del suolo (stress osmotici). Lo stress idrico porta a molti cambiamenti morfologici e fisiologici, tra cui ridotta espansione della parte aerea, limitazione della crescita radicale, diminuzione della traspirazione fogliare e dell’efficienza fotosintetica, accumulo di ioni e osmoliti, attivazione di processi di disintossicazione e parallelamente la regolazione a livello trascrizionale di un elevato numero di geni. In seguito allo stress idrico, si innesca uno stress secondario legato all’accumulo di specie reattive dell'ossigeno (ROS), quali H2O2, O2-, -OH, 1O2 e NO. Le ROS sono responsabili della maggior parte dei danni ossidativi nei sistemi biologici e nelle componenti cellulari. Un rigoroso controllo dei livelli delle ROS è obbligatorio per la sopravvivenza delle piante e il cross-talk tra l’accumulo di ROS lo stato redox è parte integrante di un preciso controllo omeostatico che gioca un ruolo fondamentale nella risposta agli stress. Le piante innescano svariati meccanismi di riduzione del livello di ROS (ROS-scavenging) volti all’induzione dell’espressione di geni che codificano per gli enzimi superossido dismutasi (SOD) , catalasi (CAT), ascorbato perossidasi e glutatione perossidasi. Recentemente è stato condotto uno studio di caratterizzazione a livello biochimico e fisiologico di M4 [(V. vinifera x V. Berlandieri) x V. berlandieri cv Resseguier n.1], un nuovo genotipo di vite candidato ad essere utilizzato come portinnesto. Questo genotipo, studiato dal 1985 dal gruppo di ricerca DiSAA dell'Università degli studi di Milano, è stato selezionato per la sua alta tolleranza allo stress idrico (WS) e salino (SS). Se confrontate con il genotipo commerciale 101.14, le piante di M4 sottoposte a deficit idrico hanno mostrato una maggiore capacità di tolleranza e una più elevata attività fotosintetica anche in condizioni di stress gravi. Nella prima parte di questa tesi sono stati osservati i risultati ottenuti da un’analisi trascrittomica condotta su larga scala (RNA -Seq), effettuata su foglie e radici dei portinnesti M4 e 101.14 campionati in condizioni di stress idrico progressivo (5 time-points). Le analisi fisiologiche sono state effettuate sulle piante trattate (deficit idrico, WS) e di controllo (irrigate, WW) lungo tutto il campionamento. L'analisi multifattoriale, che è stata condotta sui dati mRNA-Seq, ci ha permesso di valutare il peso di tre diverse componenti sulla risposta allo stress: genotipo ( R : 101.14 e M4 ), tipo di stress imposto (Trattamento, T : WW e WS) e time-point considerato ( P : T1 - T4 ). Con questa analisi stato inoltre possibile identificare i geni differenzialmente espressi (GDE) legati all’azione specifica o combinata di questi fattori (R:T , R:P , T:P e R:T:P). In WS radice si è sempre osservati un numero maggiore di GDE rispetto alla foglia. Una prima osservazione generale confrontando i risultati delle analisi multifattoriali eseguite su foglie e radici, è che nel tessuto radice il "trattamento" sembra essere la variabile che ha un impatto maggiore sull’espressione genica, mentre nel tessuto fogliare il peso del genotipo (portinnesto) sembra essere il più elevato. Questa osservazione non è sorprendente, considerato che il sistema radicale è il primo organo a percepire lo stress causato dalla carenza idrica e quello principale atto alla risposta. In questo caso è chiaro che il tipo di trattamento imposto rappresenta la variabile principale che influenza l’espressione genica mentre l'effetto del genotipo è meno determinante. Con i dati RNA-seq è stata eseguita una “Differential Cluster Analysis” (DCA), che si basa sul confronto delle correlazioni tra le espressioni dei trascritti di un organismo “reference” e di un “target”. Questa analisi ci ha permesso di identificare i pattern di co-espressione genica (T1-T4) conservati e pattern non-conservati tra M4 e 101.14. Per quanto riguarda gli ormoni vegetali, è stata osservata un’induzione dei geni legati ad auxine, jasmonati ed etilene nelle radici di M4 sottoposte a stress, mentre una sovra-regolazione degli stessi trascritti è stata osservata in 101.14. La categoria metabolica più interessante, emersa dall’analisi DCA, è quella legata ai metaboliti secondari. Infatti sono stati individuati diversi GDE legati a questa categoria sia in radice che in foglia di M4, indotti in condizioni di stress, ed è stata evidenziata una forte specificità di espressione tra i due tessuti. Infatti, in condizioni di carenza idrica, radici e foglie del genotipo tollerante M4 mostrano rispettivamente una maggiore induzione dei geni legati agli stilbeni (i.e. STS) e ai flavonoidi (e.g. CHS, F3H, LDOX, FLS). Il ruolo di questi geni potrebbe essere legato al controllo e al bilanciamento delle specie reattive dell’ossigeno (ROS), in aggiunta ai classici meccanismi di ROS-scaveging (meccanismi antiossidanti primari). In presenza di stress idrico, M4 potrebbe attuare meccanismi differenziali in radice e foglie che portano alla produzione di molecole, come resveratrolo e flavonoidi, correlate ad un sistema antiossidante secondario presente solo nel portinnesto più tollerante. La maggiore tolleranza allo stress idrico di M4, in confronto a quanto osservato in 101.14, potrebbe essere relativo a questi eventi. Nella seconda parte di questa tesi, è stato valutato l’effetto dei portinnesti M4 e 1103P su sviluppo, maturazione e qualità delle bacche di Cabernet Sauvignon (CS). Per questo esperimento sono stati campionati da piante di CS/M4 e CS/1103P acini interi a 45, 59 e 65 giorni dopo la piena fioritura (GDF). Successivamente la maggior parte delle bacche di CS/M4 avevano raggiunto l’invaiatura, si è quindi deciso di separare bucce e polpe per i campionamenti successivi, condotti a 72, 86 e 100 GDF. Sulla base dei parametri fisici (volume e colore) e chimici (solidi solubili totali, SSC), i due portinnesti hanno mostrato una diversa influenza sulla cinetica di sviluppo e maturazione delle bacche di CS. Per identificare le stesse fasi di sviluppo dei frutti raccolti da CS/1103P e CS/M4, è stato condotta un’analisi di espressione preliminare, mediante sistema real-time PCR, sui geni coinvolti nella biosintesi di fenoli, zuccheri e acidi organici. Questo approccio ha permesso di identificare la fase verde a 45 DAFB in entrambe le combinazioni d’innesto, mentre l’invaiatura è stata individuata a 72 e 86 DAFB rispettivamente per CS/M4 e CS/1103P. Le analisi mRNA-seq e micro-RNAseq sono state effettuate sulle bacche in fase di pre-invaiatura (45 GDF), invaiatura (72 GDF per CS/M4 e 86 GDF per CS/1103P) e epoca di raccolta tradizionale di CS (100 GDF). Le analisi statistiche sono state condotte sui dati RNA-seq confrontando il rapporto tra i dati di espressione di CS/M4 e CS/1103P ad ogni punto della cinetica e per entrambi i tessuti. Le analisi di “clusterizzazione” e di arricchimento hanno evidenziato la presenta di un elevato numero di GDE legati a metabolismi auxinici. Le auxine hanno un ruolo fondamentale durante lo sviluppo e sulla maturazione della bacca, si è quindi deciso di concentrare la nostra attenzione su questa classe ormonale e di eseguire una caratterizzazione e un’analsi filogenetica delle famiglie geniche ARF e AUX / IAA sul genoma di PN40024. Il ruolo delle auxine in questi processi è stato studiato anche in un altro un altro lavoro presentato in questa tesi, durante il quale è stato dimostrato che un trattamento sugli acini d’uva in fase di pre-invaiatura con l’auxina sintetica NAA causa un ritardo nella maturazione, che si manifesta a livello fisiologico e di espressione genica, parallelamente alle quali è stata osservata l’induzione di un elevato numero di trascritti atti a controllare l’omeostasi delle auxine. Le analisi condotte con il software HORMONOMETER hanno suggerito che il recupero omeostatico atto a portare i livelli dell’ormone a concentrazioni meno elevate è avvenuto a soli 7 giorni dal trattamento. Questa ipotesi è fortemente supportata dalla sovra-regolazione di geni coinvolti nella coniugazione (GH3 -like) e nell'azione ( IAA4 e IAA31 -like) delle auxine. Considerando questi risultati, le differenze osservate tra CS/M4 e CS/1103P durante lo sviluppo e la maturazione della bacca potrebbero essere collegate ad una diversa regolazione dell’auxina. Infatti, i dati di espressione (mRNA-seq, microRNA-seq e qPCR) evidenziato importanti differenze nel metabolismo auxinico tra le due combinazioni d’innesto. I nostri dati suggeriscono un coinvolgimento importante dell’ormone nel controllo dello sviluppo/maturazione della bacca grazie all’espressione di legati, da un lato all’azione delle auxine (ARF e AUX/IAA) e, dall'altro , all’omeostasi di questo ormone attraverso trascritti coinvolti nella coniugazione (GH3) e nel trasporto (PIN e ABCB). In questo contesto , anche i miRNA hanno un ruolo importante, in particolare esercitando un controllo sulla trascrizione dei geni ARF (e.g. miR160 e miR167). In fase di pre-invaiatura, le auxine hanno un’azione positiva sulla trascrizione dei geni che controllano le dimensioni della bacca (e.g. espansine) e di geni legati alla famiglia delle ARF (ad esempio VvARF8A e VvARF1A ). Parallelamente all'induzione di geni che appartengono alla famiglia ARF, è stata osservata l’induzione di trascritti che controllano i livelli (e.g. VvGH3-1) e l'azione (VvIAA9, VvIAA15A, VvIAA16) dell’ormone, suggerendo un’accurata regolazione dei livelli auxinici in queste fasi importanti dello sviluppo del frutto. Inoltre, il controllo dei livelli di auxina nella bacca d’uva sembra essere legato anche ad altri meccanismi legati all’induzione di geni legati al trasporto ormonale durante le fasi precoci (ABCBs) e tardive (PIN) della maturazione del frutto. Tenendo conto delle differenze osservate tra CS/M4 e CS/1103P nell’espressione di trascritti legati al metabolismo dell’auxina, questo ormone sembra esercitare un’azione negativa su alcuni geni legati alla maturazione della bacca (e.g. flavonoidi), ma la sua induzione nella fase di pre-invaiatura potrebbe essere necessaria per far scattare altri processi metabolici coinvolti nella maturazione dell’acino d’uva.
Kancharla, Jahnavi Reddy. "Generation of Transgenic Medicago Sativa Overexpressing "Osmotin-Chitinase" Gene Chimera." TopSCHOLAR®, 2011. http://digitalcommons.wku.edu/theses/246.
Full textMachin, Franklin Qasim. "Development of a system for high throughput screening of agrochemicals affecting plant growth behaviour." Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/31117.
Full textFantaye, Chalie Assefa Verfasser], Jonathan [Akademischer Betreuer] [Gershenzon, Ralf [Akademischer Betreuer] Oelmüller, and Ted [Akademischer Betreuer] Turlings. "The roles of plant sesquiterpenes in defense against biotic and abiotic stresses / Chalie Assefa Fantaye. Gutachter: Jonathan Gershenzon ; Ralf Oelmüller ; Ted Turlings." Jena : Thüringer Universitäts- und Landesbibliothek Jena, 2014. http://d-nb.info/1062536177/34.
Full textFantaye, Chalie Assefa [Verfasser], Jonathan [Akademischer Betreuer] Gershenzon, Ralf [Akademischer Betreuer] Oelmüller, and Ted [Akademischer Betreuer] Turlings. "The roles of plant sesquiterpenes in defense against biotic and abiotic stresses / Chalie Assefa Fantaye. Gutachter: Jonathan Gershenzon ; Ralf Oelmüller ; Ted Turlings." Jena : Thüringer Universitäts- und Landesbibliothek Jena, 2014. http://d-nb.info/1062536177/34.
Full textAlmaghamsi, Afaf. "EFFECTS OF ABIOTIC STRESSES ON SORBITOL AND RIBITOL ACCUMULATION AND SORBITOL BIOSYNTHESIS AND METABOLISM IN TOMATO [Solanum lycopersicum L.]." UKnowledge, 2019. https://uknowledge.uky.edu/pss_etds/119.
Full textMASACHCHIGE, C. N. N. NANAYAKKARAWASAM. "STUDY OF THE EFFECT OF ABIOTIC AND BIOTIC STRESS ON THE GROWTH DEVELOPMENT AND SECONDARY METABOLISM OF MEDICINAL PLANT SPECIES." Doctoral thesis, Università degli Studi di Milano, 2012. http://hdl.handle.net/2434/168729.
Full textTufail, Muhammad Aammar. "Use of plant growth promoting endophytic bacteria to alleviate the effects of individual and combined abiotic stresses on plants as an innovative approach to discover new delivery strategies for bacterial bio-stimulants." Doctoral thesis, Università degli studi di Trento, 2021. http://hdl.handle.net/11572/305571.
Full textAlberto, Diana. "Molecular mechanisms of plant-xenobiotic interactions : involvement of stress, development and hormone signaling regulations." Thesis, Rennes 1, 2017. http://www.theses.fr/2017REN1B055.
Full textHerbicides are pollutants of high concern due to their environmental ubiquity resulting from extensive use in modern agriculture and persistence in soil and water. Degradation events on active molecules mediated by microorganisms, by plants and by natural processes give rise to a plethora of herbicide metabolites of unknown impact on ecosystems. Study of plant behavior toward such complex mixtures of xenobiotic structures is important to evaluate the effects of contaminations, especially in the context of residual pollution. In order to understand the mechanisms underlying the action of this diversity of compounds, the model plant Arabidopsis thaliana was confronted to variable doses of the widely-used triazine herbicide atrazine, and of two of its metabolites, desethylatrazine and hydroxyatrazine. Short exposure to varying concentrations of atrazine, desethylatrazine and hydroxyatrazine was found to affect early growth and development in various dose-dependent and distinct manners. These differential effects pointed out to the multiple involvement of non-canonical mechanisms, directly affecting respiration and root development. In order to identify these mechanisms, which are activated in the absence of major adverse physiological effects, a genome-wide transcriptomic analysis was carried out. All of the triazines under study induced coordinated and specific changes in gene expression. Functional analysis of differentially expressed genes and of their promoters revealed that signaling pathways related to plant hormones, low energy sensing, environmental stresses and biotic interactions were involved in low-dose triazine responses. In particular, triazines affected the expression of genes known to be regulated by cytokinins. Interestingly, this family of plant hormones shares similar chemical features with triazine compounds. Developmental studies on plants bearing mutations in cytokinin sensing and signaling pathways were then carried out under variable triazine exposures. The identification of specific interactions between triazine compounds and cytokinin-signaling components highlighted potential mechanisms of competition and/or antagonism. The characterization of such signal transduction modifications and perturbations will be useful to assess herbicide efficiency in crop systems and xenobiotic contamination impact on natural plant communities. Finally, the identification of crosstalk processes between xenobiotic, abiotic and biotic stress signaling gives novel insights into the interplay between chemical pollution and climate change stressors
Ali, Mohammed Shamsher. "Molecular analysis of plant acclimation to abiotic stress." Thesis, University of Newcastle Upon Tyne, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.250106.
Full textMadeo, M. "MEDICINAL PLANT RESPONSE TO ABIOTIC AND BIOTIC STRESS." Doctoral thesis, Università degli Studi di Milano, 2010. http://hdl.handle.net/2434/150114.
Full textBalfagón, Sanmartín Damián. "High temperatures modified plant responses to abiotic stress situations." Doctoral thesis, Universitat Jaume I, 2020. http://hdl.handle.net/10803/669627.
Full textLas plantas cultivadas se ven afectadas por numerosas condiciones ambientales adversas al mismo tiempo. Cuando dos o más factores abióticos afectan a las plantas de manera simultánea se crea una nueva condición de estrés, diferente a la provocada por los estreses individuales. La temperatura de la superficie terrestre está aumentando, y esto viene acompañado por otros cambios medioambientales. Todos estos cambios afectan a las zonas de cultivos de todo el mundo y a la producción agrícola. El objetivo principal de esta tesis es estudiar el impacto en la fisiología de las plantas de diversos estreses abióticos en combinación con las altas temperaturas. Para conseguir este propósito, este trabajo se ha enfocado en el estudio de las respuestas fisiológicas, hormonales y transcriptómicas de las plantas a diferentes condiciones de estrés para obtener una visión global del mecanismo de tolerancia de las plantas a situaciones complejas de estrés abiótico.
South, Kaylee. "Improving abiotic and biotic stress tolerance in floriculture crops." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1595499762154056.
Full textMendu, Venugopal. "ROLES OF MICRORNAS IN PLANT ABIOTIC STRESS, DEVELOPMENT AND VIRAL INFECTION." UKnowledge, 2008. http://uknowledge.uky.edu/gradschool_diss/663.
Full textAmara, Imen. "Abiotic stress in plants: Late Embryogenesis Abundant proteins." Doctoral thesis, Universitat de Barcelona, 2012. http://hdl.handle.net/10803/83820.
Full textLas proteínas LEA, originalmente fueron descritas en las semillas de algodón; se acumulan en grandes cantidades en estructuras tolerantes a la desecación (semillas, polen) y en tejidos vegetativos sometidos a estrés abiótico, sequía, salinidad y frío. También se hallan en organismos anidrobióticos, en plantas de resurrección, algunos invertebrados y microorganismos. La presencia de proteínas LEA se correlaciona con la adquisición de tolerancia a la desecación. Desde un principio se les atribuyó un papel en las respuestas de las plantas en la adaptación al estrés (revisado en Bartels and Salamini 2001, Tunnacliffe 2007, Shih et al. 2010, Tunnacliffe 2010, Hand et al. 2011). Las proteínas LEA se clasifican en diversos grupos en función de dominios y secuencias de aminoácidos específicos (Wise 2010, Batagglia et al 2008, Bies-Ethève et al 2008). Los grupos 1, 2 y 3 son los más relevantes ya que abarcan la mayoría de las proteínas de la familia LEA. Una característica general de estas proteínas es su elevada hidrofilicidad, alto contenido de aminoácidos cargados y su falta de estructura en estado hidratado. A pesar de encontrarse mayoritariamente en forma de “random coil”, algunas adquieren un cierto grado de estructura durante la deshidratación o en la presencia de agentes promotores de α-hélices (Shih et al. 2010, Hand et al. 2011). A nivel celular se han hallado en todas las localizaciones, citosol, núcleo, nucleolo, mitocondria, cloroplasto, vacuola, retículo endoplásmico, peroxisoma y membrana plasmática, donde se supone ejercen su función protectora frente al estrés (Tunnacliffe and Wise 2007, Hundertmark and Hincha 2008). En relación a las modificaciones post-traduccionales, algunas se hallan fosforiladas (Jiang and Wang 2004; Plana et al. 1991, Heyen et al. 2002, Rohrig et al. 2006). Los efectos protectores de las varias proteínas LEA se han demostrado mediante ensayos in vitro y en aproximaciones transgénicas que han dado lugar a fenotipos resistentes a la sequía, sal y frío. Por lo general, se considera que estas proteínas contribuyen a la protección y a la estabilización de macromoléculas y estructuras celulares en las respuestas de adaptación al estrés en plantas; sin embargo, sus funciones específicas aún no han sido esclarecidas. A nivel molecular se ha propuesto que las funciones de las proteínas LEA pueden ser variadas: estabilización y renaturalización de proteínas, mantenimiento de membranas, en combinación, o no, con azúcares, tampones de hidratación (substitución de moléculas de agua), afinidad por iones y función antioxidante (Tunnacliffe and Wise 2007, Shih et al. 2010, Batagglia et al. 2008). Para finalizar, diremos que los objetivos principales de esta tesis consisten en ampliar los conocimientos sobre las proteínas LEA y sus funciones relativas a la tolerancia a la sequía. Los resultados están presentados en forma de capítulos.
Abeykoon, Walawwe Sashila. "Regulation of photosynthesis in plants under abiotic stress." Thesis, University of Manchester, 2014. https://www.research.manchester.ac.uk/portal/en/theses/regulation-of-photosynthesis-in-plants-under-abiotic-stress(25e36741-2b94-49e9-a660-487b913fd123).html.
Full textMaclear, Athlee. "Identification of cis-elements and transacting factors involved in the abiotic stress responses of plants." Thesis, Rhodes University, 2005. http://hdl.handle.net/10962/d1007236.
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Nordstedt, Nathan P. "Isolation and characterization of novel bacterial strains to alleviate abiotic stress in greenhouse ornamental crops." The Ohio State University, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=osu1617740819791342.
Full textPeñalosa-Barbero, Andrés. "New signalling network in plant abiotic stress discovered through a genetic approach." [S.l. : s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=97211131X.
Full textWeerathunga, Arachchilage Achira S. "A Novel Transcription Factor in Arabidopsis thaliana Abiotic Stress Response." ScholarWorks@UNO, 2015. http://scholarworks.uno.edu/td/2114.
Full textKarunaratne, Asha Sajeewani. "Modelling the response of Bambara groundnut (Vigna subterranea (L.) Verdc) for abiotic stress." Thesis, University of Nottingham, 2009. http://eprints.nottingham.ac.uk/10840/.
Full textDong, Shaowei. "Expression of duplicated genes in a polyploid plant in response to abiotic stress." Thesis, University of British Columbia, 2009. http://hdl.handle.net/2429/13465.
Full textLima, Aurenivia BonifÃcio de. "Oxidative responses in double rice plants silenced in cytosolic apx subjected to abiotic stresses." Universidade Federal do CearÃ, 2011. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=7578.
Full textO H2O2 à tido como molÃcula sinalizadora de vÃrios eventos celulares e seu nÃvel endÃgeno à controlado pelas diferentes isoformas de APX e CAT que estÃo distribuÃdas na cÃlula vegetal. No presente estudo, foram utilizadas diferentes abordagens visando um melhor entendimento do papel das isoformas citosÃlicas de APX, consideradas por muitos autores as isoformas mais importantes dentre as APXs, e sua sincronia com CAT, tendo em vista que estas sÃo as principais removedoras do H2O2 intracelular. Inicialmente, foi observado que plantas de arroz submetido à combinaÃÃo de estresse salino e alta temperatura apresentaram modulaÃÃo positiva da atividade de APX associada com menor acÃmulo de H2O2. Intrigantemente, plantas duplamente silenciadas nas isoformas de APX citosÃlica (APx1/2s) apresentaram desenvolvimento normal em condiÃÃes controle. Em condiÃÃes estressantes, as APx1/2s exibiram um mecanismo antioxidativo compensatÃrio mediado principalmente pelas isoformas de GPX citosÃlica e cloroplÃstica juntamente com antioxidantes nÃo enzimÃticos. AlÃm disso, as APx1/2s submetidas a inibiÃÃo irreversÃvel de CAT apresentaram melhor desempenho fotossintÃtico e menores danos oxidativos que plantas que continham a APX citosÃlica, CAT ou ambas indicando que outros mecanismos compensatÃrios foram ativados para mitigar os possÃveis efeitos negativos do acÃmulo de H2O2. Tomados em conjunto, os dados indicam que as isoformas citosÃlicas de APX nÃo sÃo as enzimas mais importantes no controle dos nÃveis de H2O2, visto que plantas com ausÃncia destas isoformas completam o ciclo de vida e sÃo capazes de enfrentar situaÃÃes de estresse. AlÃm disso, à possÃvel afirmar que a aÃÃo coordenada das isoformas de GPX, juntamente com ascorbato e glutationa reduzidos, podem ser os responsÃveis pela manutenÃÃo do equilÃbrio redox celular em condiÃÃes estressantes em plantas de arroz, diferente do que à noticiado para a planta-modelo Arabdopsis.
Plants in the field are exposed to multiple stresses, such as salinity, drought, high light, heat/cold and others, resulting in different physiological responses. T o evaluate the consequences of some of these stresses to the photosynthetic apparatus and an tioxidative metabolism, 30 day old rice plants , were submitted to the following treatments: control (without NaCl and at 27 ÂC), heat stress (without NaCl and at 42 ÂC), salt stress (with 100 mM NaCl and at 27 ÂC) and combined stress (salt+heat). The contr ol and salt stress treatments lasted 8 days and the heat and combined stress treatments lasted 6 hours. At the end of the experimental period, gas exchange, chlorophyll fluorescence and electrolyte leakage were measured and the leaves were collected for bi ochemical determinations. I solated salt and heat stress es were not sufficient to cause damage in the photochemical apparatus and heat stress only modifie d stomatal aperture. In combined heat and salt stress , the results indicate that photosynthetic process es were affected at the level of CO 2 assimilation and quantum efficiency. E lectrolyte leakage, TBARS and H 2 O 2 content were elevated in sal t +heat treatment, but in isolate d heat stress the TBARS was decreased. Reduced ascorbate and glutathione were similarly decrease d in plants exposed to the combination of salt and heat. A ll enzymes examin ed here were differently modulated in experimental treatment s . Taken together, the data indicates more intense impairment of photosynthesis in rice plants in the c ombination of the salt and heat, however the effective modulation of the antioxidative system was eff ective in establishing a new redox homeostasis and providing tolerance to abiotic stress.
Nylander, Maria. "Molecular responses to abiotic stress in Arabidopsis thaliana /." Uppsala : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 2000. http://epsilon.slu.se/avh/2000/91-576-5766-1.pdf.
Full textEriksson, Sylvia. "Molecular properties of disordered plant dehydrins : Membrane interaction and function in stress." Doctoral thesis, Stockholms universitet, Institutionen för biokemi och biofysik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-136033.
Full textAt the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 4: Manuscript. Paper 5: Manuscript.
Vives, Peris Vicente. "Interaction of citrus root exudates with plant growth promoting rhizobacteria under abiotic stress conditions." Doctoral thesis, Universitat Jaume I, 2018. http://hdl.handle.net/10803/461915.
Full textIn nature, plants are constantly releasing a mixture of metabolites through the roots known as root exudates. Its composition can be affected by different stimuli, including abiotic stress conditions as salinity or high temperatures. Chapter 1 demonstrates that citrus rootstocks Carrizo citrange and Citrus macrophylla exude different concentrations of proline and phytohormones depending on the abiotic stress condition and the genotype. Chapter 2 studies the effect of citrus root exudates from salt- and heat-stressed plants on the rhizobacteria Pseudomonas putida KT2440 and Novosphingobium sp. HR1a, which generally promote their growth. Moreover, the presence of proline and salicylates in root exudates was also tested through the analyses of the expression of the promoters PputA and PpahA of P. putida KT2442 and Novosphingobium sp. HR1a, respectively. Finally, Chapter 3 reveals the beneficial effect of both bacterial strains in C. macrophylla plants subjected to salt stress conditions.
Emam, Taraneh Megan. "The Role of Soil Biota, Abiotic Stress, and Provenance in Plant Interactions and Restoration." Thesis, University of California, Davis, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=3706585.
Full textIn this dissertation, I asked how soil biota, abiotic stress, and plant provenance influence plant communities and interactions between plants. Soil biota can have positive or negative effects on individual plants, and also influence the diversity and productivity of plant communities through their net effects on individuals and by mediating plant-plant interactions. However, the level of abiotic stress experienced by plants is likely to drive plant responses to soil mutualists and antagonists. Additionally, plant provenance (e.g. population origin) can influence responses to abiotic soil conditions as well as to soil organisms. Understanding how these three interacting components shape plant interactions may improve success of restoration and invasive plant management. During restoration, the goal is typically to create conditions conducive to native plant reestablishment. However, amelioration of disturbed areas by reducing abiotic stress or by adding beneficial soil organisms may unintentionally increase colonization and growth of non-native plants. Using the applied context of mine restoration, I examined how soil biota, abiotic stress, and plant provenance affected plant communities and interactions in four studies.
In Chapter 1, I found that both a native grass (Bouteloua gracilis ) and an invasive grass (Bromus tectorum) responded positively to soil biota when grown alone in the greenhouse. However, when grown together, the presence of soil biota increased the competitive ability of Bromus, while the removal of soil biota increased competition by Bouteloua. Results supported the hypothesis that invasive species such as Bromus often have positive responses to soil biota in the invaded range, but I also found that Bromus response to soil biota removal varied considerably by site.
In Chapters 2 and 3, I examined how methods used during restoration (application of stockpiled soil and inoculation with soil biota) affected native and non-native plant growth in field plots. I found that native plant biomass and non-native plant biomass both tended to increase when soil abiotic stress was ameliorated through the addition of deeper stockpiled soil. In addition, both native and non-native grasses responded positively to the use of local soil an as inoculant, while non-native forbs responded negatively to local soil inoculum. However, native plants only received significant benefits from inoculation when targeted application to native seedling transplants was used. Commercial mycorrhizal fungal inoculum did not affect plant growth. In studies of both stockpiled soil addition and soil inoculation, year was an important factor in determining plant responses. Variation in effects by year may reflect differences in precipitation timing or amount, or changes associated with plant and soil biota growth over time.
In Chapter 4, I used a greenhouse experiment to examine how one type of soil biota, arbuscular mycorrhizal fungi (AMF), influenced plant-plant interactions. I also manipulated abiotic stress (soil phosphorus availability) and plant provenance (stress-tolerant ecotype versus competitive ecotype) to assess whether these factors influenced AMF-mediated interactions among plants. I found that allowing or denying AMF hyphal access between neighboring pots altered plant reproduction. Inflorescence production was substantially decreased when hyphal access was allowed between two stress-tolerant plants. In addition, when hyphal access was permitted from a stress-tolerant plant to a competitive plant, the competitive plant flowered slightly sooner, whereas allowing hyphal access between two stress-tolerant plants led to slightly slower flowering. These results did not appear to be driven by abiotic stress or plant nutrition. It is possible that AMF transmission of infochemicals may play a role in regulating plant phenology and reproduction; however, further research in this area is needed.
Nguyen, Hong Chien. "Eucalyptus DREB regulation pathway : control of abiotic stress tolerance, plant development and wood formation." Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30115/document.
Full textEucalyptus, the most widely planted hardwood in the world, is highly exposed to the cold due to the lack of dormancy. DREB (Drought Responsive Element Binding) genes are known as master regulators of abiotic stress response. A high number of the DREB1/CBF (C-Repeat Factor) genes has been annotated in Eucalyptus grandis. The aim of the study was to better understand the role of DREB pathway in Eucalyptus for the control of stress tolerance, development and wood formation. The present study provides an annotation of the CBF and DREB2 genes from a partial draft of the E. gunnii genome sequence. A comprehensive transcriptional analysis through high-throughput qRT-PCR was carried out on different organs from the two Eucalyptus species after stress treatments. An additional CBF copy in the E. gunnii genome compared to E. grandis suggests that this group is still evolving unlike the DREB2 group. The higher CBF transcript amounts in the cold tolerant E. gunnii together with higher induction rates in the fast growing E. grandis suggest that CBF factors promote both stress protection and growth limitation. In addition, transcription factors from MYB, NAC, KNOX and AP2/ERF families involved in the control of growth and cell wall formation have been identified as putative CBF target genes. These results are in agreement with the modified phenotype of CBF overexpressors. Both approaches suggest a central role of DREB pathway in the trade-off between growth and stress resistance in this woody species
John-Bejai, Carus Kristoff Joel. "Wheat floral biology : prospects for improving the efficiency of hybrid seed production and abiotic stress tolerance." Thesis, University of Nottingham, 2018. http://eprints.nottingham.ac.uk/49925/.
Full textBerenguer, Helder Duarte Paixão. "Eucalyptus predisposition to Neofusicoccum kwambonambiense under water stress." Master's thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/22330.
Full textIn Portugal, Eucalyptus, particularly Eucalyptus globulus, occupies more than 800 000 ha and, due to being a major source of biomass for fiberboard, industrial charcoal, fuel wood and paper pulp, has become a key genus, with a considerable economic importance. However, E. globulus productivity faces new pressures, with climate change-driven drought as one of the most hostile ones. Drought can lead to growth impairment and yield reduction: directly; or indirectly, through the increase of plant susceptibility to pathogens by a predisposition mechanism. Neofusicoccum kwambonambiense is an endophytic opportunist phytopathogen known to severely affect E. globulus, whose incidence has already been reported in Portugal. Taking all in consideration, it is of major importance to assess the predisposition effect that drought may have on the N. kwambonambiense - E. globulus interaction. For such purpose, four treatment groups were established: E. globulus were firstly subjected to a 66-days acclimation period in which plants were periodically watered (80% of field capacity). After that, two groups were exposed to a progressive water supply restriction. The other two remained well-watered. Once water-stressed plants achieved 18% of field capacity (23 days), a well-watered and a water-stress group were inoculated with N. kwambonambiense. All treatments were kept in these conditions throughout a 65 days’ period, at which moment a set of morphological, physiological and biochemical parameters was obtained. Well-watered plants, despite being infected with N. kwambonambiense, presented an overall photosynthetic increase, which enabled plant defense through the production of sugars, proline and salicylic acid. Oxidative damages (partially observed through malondialdehyde content), were avoided in part due to proline and soluble sugars. Water stress lead to a direct growth impairment confirmed through an indole-acetic-acid content decrease. A water-potential reduction occurred, which, together with abscisic acid, lead to stomatal closure and overall photosynthetic efficiency decline. Oxidative damages weren’t properly managed and further affected E. globulus. Furthermore, N. kwambonambiense was found to promote a jasmonic acid content increase, typical of necrotrophic pathogens, which may suggest a lifestyle change from hemibiotrophic to necrotrophic as plant cells progressively degenerate. Ultimately, water-stressed E. globulus presented larger external lesion extensions and steam cankers and a superior internal fungi progression. Our results conclusively demonstrate that water stress created a better substrate for fungi development and decreased the plant’s ability to respond. Such resulted in higher susceptibility and disease severity confirming predisposition.
Em Portugal, o eucalipto, particularmente o Eucalyptus globulus, ocupa mais de 800 000 ha. Devido a ser uma importante fonte de biomassa para painéis de fibras, carvão industrial, lenha e pasta de papel, tornou-se um género chave de considerável importância económica. Contudo, a produtividade de E. globulus tem encontrado novas pressões, sendo a seca resultante das alterações climáticas, uma das mais hostis. A seca pode levar a uma diminuição do crescimento e produtividade: diretamente; ou indiretamente através do aumento da suscetibilidade a agentes patogénicos através da predisposição. O fungo ascomiceto Neofusicoccum kwambonambiense é um agente fitopatogénico endofítico oportunista que se sabe afetar severamente E. globulus, e cuja presença já fora confirmada em Portugal. Tomando tal em consideração, torna-se importante avaliar o efeito de predisposição que a seca poderá ter na interação N. kwambonambiense - E. globulus. Para tal foram criados quatro grupos de tratamento: E. globulus foram primeiramente sujeitos a um período de aclimatização de 66 dias no qual foram periodicamente irrigados (80% de capacidade de campo). Seguidamente, dois grupos foram sujeitos a uma diminuição progressiva da irrigação. Os outros dois grupos permaneceram bem regados. Uma vez que os tratamentos stressados atingiram 18% de capacidade de campo (23 dias), um grupo bem regado e um grupo stressado foram inoculados com N. kwambonambiense. Todas os tratamentos foram mantidos nestas condições durante um período de 66 dias, findo o qual foi obtido um conjunto de parâmetros morfológicos, fisiológicos e bioquímicos. As plantas bem regadas, apesar de terem sido inoculadas com N. kwambonambiense apresentaram um aumento dos parâmetros fotossintéticos o que terá permitido a defesa da planta através de uma produção amplificada de açúcares, prolina e ácido salicílico. Danos oxidativos (parcialmente observados através do conteúdo em malondialdeído) foram evitados, em parte, devido à ação da prolina e açúcares solúveis. O stress hídrico levou a uma diminuição do crescimento confirmado pela redução do conteúdo em ácido-indole-acético. Ocorreu uma diminuição do potencial hídrico, a qual, em conjunto com o aumento do ácido abscísico, levou ao fecho dos estomas e diminuição da fotossíntese. Os danos oxidativos não foram controlados, afetando o estado do E. globulus. Ademais, o N. kwambonambiense provocou um aumento do conteúdo em ácido jasmónico, típico de agentes patogénicos necrotróficos, o que poderá sugerir que o fungo passou de um estilo de vida hemibiotrófico para necrotrófico, à medida que as células degeneravam. Os E. globulus stressados apresentavam maiores lesões externas e cancros, conjuntamente com uma maior progressão interna do fungo. Os nossos resultados comprovam que a seca criou um melhor substrato para o desenvolvimento do fungo e diminuiu a capacidade de resposta da planta. Tal resultou num aumento da suscetibilidade e severidade da doença confirmando a predisposição.
Migicovsky, Zoë. "Transgenerational inheritance of epigenetic response to abiotic stress in Arabidopsis thaliana." Thesis, Lethbridge, Alta. : University of Lethbridge, Dept. of Biological Sciences, c2012, 2012. http://hdl.handle.net/10133/3311.
Full textxiv, 246 leaves : ill. ; 29 cm
Wu, Qingyu. "Improvement of abiotic stress tolerance and calcium-deficiency disorder resistance of tomato plants." Diss., Kansas State University, 2012. http://hdl.handle.net/2097/14033.
Full textDepartment of Horticulture, Forestry, and Recreation Resources
Sunghun Park
Plants are continuously exposed to numerous abiotic stresses, which adversely affect plant growth, development, and yield. Plants have developed different signaling pathways to cope with abiotic stresses, and some of the pathways converge to help plants tolerate simultaneous stresses. Here, we report ectopic expression of an Arabidopsis glutaredoxin AtGRXS17 that confers tolerance to multiple abiotic stresses in tomato plants. In yeast assays, AtGRXS17 co-localized with yeast ScGrx3 in the nucleus and suppressed the sensitivity of yeast grx3grx4 double mutants to oxidative stress and heat shock. In plants, GFP-AtGRXS17 fusion proteins initially localized in the cytoplasm but migrated to the nucleus during heat stress. Ectopic expression of AtGRXS17 in tomato plants minimized photo-oxidation of chlorophyll and reduced oxidative damage of cell membrane systems under heat stress. Furthermore, expression of the heat shock transcription factor (HSF) and heat shock protein (HSP) genes was up-regulated in AtGRXS17-expressing tomato plants during heat stress when compared to wild-type controls. Under cold, drought, and oxidative stress conditions, AtGRXS17-expressing tomato plants also displayed more vigorous growth and less physiological damage than those of the wild-type control plants. Quantitative real-time PCR (qRT-PCR) analysis indicated that expression of AtGRXS17 alters multiple stress defense signaling pathways, including the Abscisic Acid (ABA) and C-Repeat Binding Factors (CBF) pathways. The results revealed a conserved function for a glutaredoxin protein in abiotic stress adaptation, and manipulation of AtGRXS17 may be a useful approach to improve crop stress tolerance and understand plant signaling under abiotic stress conditions. Deregulated expression of an Arabidopsis H[superscript]+/Ca[superscript]2[superscript]+ antiporter (sCAX1) in agricultural crops increases total calcium (Ca[superscript]2[superscript]+) but may result in yield loses due to calcium-deficiency like symptoms. Here we demonstrate that co-expression of a maize calreticulin (CRT, a Ca[superscript]2[superscript]+ binding protein located at endoplasmic reticulum) in sCAX1-expressing plants mitigated these adverse effects while maintaining enhanced Ca[superscript]2[superscript]+ content. Co-expression of CRT and sCAX1 could alleviate the hypersensitivity to ion imbalance in tobacco plants. Furthermore, blossom-end rot (BER) in tomato may be linked to changes in CAX activity and enhanced CRT expression mitigated BER in sCAX1 expressing lines. These findings suggest that co-expressing Ca[superscript]2[superscript]+ transporters and binding protein at different intracellular compartments can alter the content and distribution of calcium within the plant matrix.
Colling, Janine. "Towards understanding the metabolism of in vitro Sutherlandia frutescens (L.)R.Br. cultures." Thesis, Stellenbosch : University Stellenbosch, 2009. http://hdl.handle.net/10019.1/4601.
Full textENGLISH ABSTRACT: Sutherlandia frutescens (L.) R. Br., also regarded as Lessertia frutescens, is a leguminous, perennial shrub indigenous to South Africa. Extracts prepared from the leaves have traditionally been used for the treatment of various diseases. Reports have also indicated that S. frutescens provides certain health benefits to cancer and HIV/AIDS patients. Analysis of extracts indicated the presence of several compounds (bitter triterpenoid glycosides, several flavonoids, amino acids, small amounts of saponins (no alkaloids though), asparagine, Larginine, canavanine, gamma-aminobutyric acid (GABA) and pinitol) which contribute to the medicinal properties of this plant. The first part of this study involved testing the effect of six treatments (light, dark, soaking of seeds, physical scarification, chemical scarification and flaming of seeds) on the in vitro germination of Sutherlandia seeds to elucidate the factors which control seed germination. Those treatments which removed the seed coat were most successful for germination with physical scarification being the most efficient method, resulting in 98.6% of the seeds germinating after 21 days. Although the organogenesis of Sutherlandia explants (cotyledons and hypocotyls) in vitro were investigated (results not included in this thesis), omitting plant growth regulators (PGR) in the cultivation medium was best for shoot multiplication. However, this PGR-free system successfully provided a continuous supply of plant material for further studies. It would be possible to successfully adopt it for commercial production of plants to assist with cultivation of Sutherlandia as a field crop. Another advantage of this system is spontaneous rooting with 85% of the in vitro microshoots rooting in PGR-free medium. These rooted plants were acclimated in the glasshouse using vented lids to harden off the shoots and this method resulted in 100% survival of plants. The second part of this study investigated the induction of hairy root cultures of S. frutescens using Agrobacterium-mediated transformation. The efficiency of three Agrobacterium strains (A4T, LBA9402 and C58C1) to transform different S. frutescens explants (cotyledons and hypocotyls) was analyzed. All three strains were equally efficient at inducing hairy roots in both hypocotyls and cotyledons. However, transformation of S. frutescens was dependent on the type of explant used with the hypocotyls being more efficiently transformed than the cotyledons. Overall the transformation of both the hypocotyl (93%) and cotyledon (47%) was highest when the strain A4T was used. Four hairy root clones were selected and their cultivation in a liquid system was optimized by investigating their growth in four different types of media (Gamborg B5 (Gamborg et al., 1968), White’s (White, 1934; White, 1954), MS (Murashige and Skoog, 1962) and half strength MS medium). All the growth of hairy root clones was best in the B5 and MS medium, with White’s medium being the least effective cultivation medium. Molecular analysis of hairy roots was used to prove the transgenic status of these four putative transgenic clones. This was achieved using polymerase chain reaction (PCR) amplification of rol A (320 bp), B (780 bp) and C (600 bp) genes to determine the presence of the TL-DNA in the plant genome. During Southern hybridization a radioactively labeled rol A probe was used to determine the copy number of the rol A gene. The three rol genes were present in all four hairy root clones. The third part of this study focused on the effect of three abiotic stress factors (nitrogen availability, salinity and drought) on the synthesis of four metabolites (gamma-aminobutyric acid (GABA), asparagine, arginine and canavanine). The effect of nitrogen availability on metabolite synthesis and the morphology was determined using in vitro shoot cultures as well as the hairy root clone C58C1-g. Nitrogen availability studies were conducted by cultivating the microshoots or root tips on modified MS medium. The MS medium contained either the normal amount of nitrogen (1.9 g L-1 KNO3 and 1.65 g L-1 NH4NO3) in the MS medium (1x nitrogen), half the normal nitrogen concentration in MS medium (0.5x nitrogen) or twice the normal nitrogen concentration in MS medium (2x nitrogen). The arginine and asparagine levels in the roots and shoots and the canavanine level in the shoots were directly correlated with the amount of nitrogen in the medium (as the nitrogen level increased, the metabolite levels increased). The GABA level in the shoots was inversely correlated with the amount of nitrogen in the medium. Several reasons may explain these metabolic changes including the assimilation of extra nitrogen into asparagine, canavanine and arginine in the shoots. The reduced GABA levels may indicate the preferential flux of the free GABA into other nitrogen assimilatory pathways such as protein synthesis as well as its rapid utilization to replenish the tricarboxilic acid cycle intermediates. The effect of water (induced by including 3% (w/v) PEG in the medium) and salt stress (induced by including either 50 or 100 mM NaCl in the medium) was only investigated in the shoot cultures as the root cultures lacked the synthesis of canavanine. Water stress did not significantly alter the metabolite levels, but resulted in a significant decrease in the growth (fresh weight and total shoot length) and the rooting response of these microshoots. Salt stress only resulted in a significant increase in arginine levels with increasing salinity and also caused a reduction in the rooting and growth response. Lowered plant vigour may be the first visual sign of water stress. Addition of NaCl may lead to ion toxicity and requires osmotic adjustment resulting in changes at the metabolic level concomitant to physiological growth changes. Finally, the anti-bacterial activity and the phytochemistry of transgenic root cultures and untransformed in vitro and ex vitro plant material was examined. Only the extracts prepared from the wild harvested leaf material exhibited moderate anti-bacterial activity (1.25 mg ml-1) against all the bacteria (Escherichia coli, Klebsiella pneumoniae, Bacillus subtilis and Staphylococcus aureus) tested. Changes to the secondary metabolism of hairy roots were investigated using TLC and LC-MS analysis. Several of the compounds in the hairy root extracts were present in higher levels than in the control root extracts. Transformation also increased the complexity of the phytochemical pattern of the hairy roots, either due the synthesis of novel compounds or upregulated synthesis of existing metabolic pathways. The production of hairy roots and the establishment in a liquid system during this study was an important step towards upscaling these cultures to a bioreactor. In future these roots can assist in developing cultures which produce a high yield of the desired metabolites.
AFRIKAANSE OPSOMMING: Sutherlandia frutescens (L.) R. Br., ook bekend as Lessertia frutescens is ‘n peulagtige meerjarige struik, inheems tot Suid Afrika. Ekstrakte wat van die blare voorberei word, is tradisioneel gebruik vir die behandeling van verskeie siektes. Berigte het ook daarop gedui, dat S. frutescens sekere gesondheidsvoordele vir kanker en HIV/VIGS pasiënte inhou. ‘n Ontleding van die ekstrakte, dui op die teenwoordigheid van verskeie verbindings (bitter triterpenoïed glikosiede, verskeie flavonoïede, aminosure, klein hoeveelhede saponiene (alhoewel geen alkaloïede), asparagien, L-arginien, canavanien, gamma-aminobottersuur (GABS) en pinitol) wat tot die medisinale eienskappe van hierdie plant bydrae. Die eerste deel van die studie het die effek van ses behandelings (lig, donker, week van sade, fisiese skarifikasie, chemiese skarifikasie en die vlam van sade) op die in vitro ontkieming van Sutherlandia sade getoets met die doel om die faktore wat saadontkieming beheer, te identifiseer. Die beste behandeling vir saadontkieming was dié behandelings wat die saadhuid verwyder het. Die mees effektiewe metode van saadhuidverwydering was die fisiese skarifikasie van sade, wat gelei het tot ‘n 98.6% ontkieming van sade na 21 dae. Alhoewel in vitro organogenese van Sutherlandia eksplante (kotiel en hipokotiel) ondersoek was (resultate nie ingesluit in die tesis nie), was plant groei reguleerders (PGR) uitgesluit in die groeimedium om stingelvermeerdering te bevorder. Nie te min was die PGR-vrye sisteem suksesvol om ‘n voortdurende bron van plant material vir verder studies te verskaf. Dit sou egter moontlik wees om die PGR-vrye sisteem suksesvol te kon aanpas vir die kommersiële produksie van plante met die doel om Sutherlandia as ‘n landbougewas te bevorder. ‘n Verdere voordeel van dié sisteem, is die spontane wortelvorming, met 85% van die in vitro mikrostingels wat wortels in die PGR-vrye medium produseer het. Hierdie bewortelde plante was in die glashuis geakklimatiseer met behulp van geventileerde deksels (vir stingel afharding) en het tot ‘n 100% oorlewing gelei. Die tweede deel van die studie het die induksie van S. frutescens harige wortelkulture met behulp van Agrobacterium-bemiddelde transformasie ondersoek. Die effektiwiteit van drie Agrobacterium stamme (A4T, C58C1 en LBA9402) om verskillende S. frutescens eksplante (kotiel en hipokotiele) te transformeer, was geanaliseer. Al drie stamme was ewe effektief om harige wortels op beide hipokotiel en kotiele te induseer. S. frutescens transformasie blyk egter tog van die tipe eksplant afhanklik te wees, aangesien die hipokotiele meer effektief as die kotiele getransformeer kon word. Met inagneming van beide die hipokotiel (93%) en kotiel vii (47%), was transformasie optimaal met die gebruik van die A4T stam. Vier harige wortelklone was geselekteer en hulle produksie in ‘n vloeibare sisteem was geoptimiseer deur hulle groei in vier verskillende tipe media (Gamborg B5 (Gamborg et al., 1968), White’s (White, 1934; White, 1954), MS (Murashige and Skoog, 1962) en half-sterkte MS medium) te ondersoek. B5 en MS medium was beskou as die beste vir alle die harige wortelklone se groei, terwyl White’s medium die minste doeltreffende groeimedium was. Molekulêre analise van die harige wortels was gebruik ten einde die transgeniese status van die vier vermoedelike transgeniese klone te bewys. Dit was behaal deur polimerase kettingreaksie amplifisering (PKR) van die rol A, B en C gene ten einde die teenwoordigheid van die TL-DNS in die plant genoom aan te toon. Tydens Southern hibridisasie was ‘n radioaktief gemerkte peiler gebruik om die aantal rol A geen kopieë te bepaal. Die drie rol gene was teenwoordig in al vier harige wortelklone. Die derde deel van die studie het gefokus op die effek van drie abiotiese stress faktore (stikstof beskikbaarheid, sout- en droogte stres) op die produksie van vier metaboliete (GABS, asparagien, canavanien en arginien). Die effek van stikstof beskikbaarheid op die metaboliet produksie asook die morfologie was bestudeer deur gebruik te maak van in vitro mikrostingels asook die harige wortel kloon C58C1-g. Stikstof beskikbaarheidstudies was uitgevoer deur die mikrostingels of wortelpunte in ‘n gewysigde MS medium te groei. Die MS medium was aangepas om die normale hoeveelheid stikstof (1.9 g L-1 KNO3 en 1.65 g L-1 NH4NO3) in MS medium (1x stikstof), of die helfte van die normale stikstof konsentrasie (0.5x stikstof) of twee keer die normale stikstof konsentrasie in MS medium (2x stikstof) te bevat. Die arginien en asparagien vlakke in die wortels en stingels, asook die canavanien vlak in die stingels was positief gekorreleerd aan die stikstof konsentrasie in die medium. Die GABS vlak in die stingels was egter omgekeerd eweredig aan die stikstof konsentrasie in die medium. Verskeie redes kan aangevoer word om die metaboliet veranderinge te verduidelik, insluitende die assimilasie van addisionele stikstof in asparagien, canavanien en arginien in die stingels. Die verlaagde GABS vlakke kan dui op die voorkeur van vrye GABS vloei na ander stikstofassimilerende metaboliese paaie soos proteïen sintese, asook die snelle benutting van GABS ten einde die Trikarboksielsuursiklus intermediêre produkte aan te vul. Die effek van droogte (geïnduseer deur die byvoeging van 3% (m/v) PEG tot die medium) en sout stres (geïnduseer deur 50 of 100 mM NaCl byvoeging tot die medium) was slegs in die stingel kulture ondersoek weens die afwesigheid van canavanien produksie in die wortel kulture. Water stres het nie ‘n betekenisvolle verandering in die metaboliet vlakke meegebring nie, maar dit het wel tot ‘n beduidende afname in groei (vars massa en totale stingel lengte) en bewortelingsreaksie in die mikrostingels gelei. Sout stres het slegs tot ‘n betekenisvolle viii toename in arginien vlakke asook ‘n afname in die wortelvorming en groeireaksie tydens die toenemende sout vlakke gelei. ‘n Verlaging in plant groeikragtigheid mag ‘n eerste visuele teken van water stres wees. Die toevoeging van NaCl tot die medium kan tot ioontoksisiteit lei en plante reageer deur middel van osmotiese aanpassing wat tot veranderinge in die metaboliet vlakke asook veranderinge in fisiologiese groei, lei. Die finale deel van die studie het die anti-bakteriële aktiwiteit en die fitochemie van die transgeniese wortel kulture asook die ongetransformeerde in vitro en ex vitro plant materiaal ondersoek. Slegs die ekstrakte verkry vanaf blaar materiaal geoes uit die natuur, het matige anti-bakteriële aktiwiteit (1.25 mg ml-1) teen al die bakterië (Escherichia coli, Klebsiella pneumoniae, Bacillus subtilis en Staphylococcus aureus) wat ondersoek is, getoon. Aanpassings in die sekondêre metabolisme van die harige wortels is deur middel van dunlaag chromatografie (DLC) en vloeibare chromatografie-massa spektroskopiese (VC-MS) analise ondersoek. Verskeie verbindings was in hoër vlakke in die harige wortels teenwoordig, as in die kontrole wortel ekstrakte. Transformasie het ook die kompleksiteit van die harige wortels se fitochemiese patroon verhoog, moontlik weens die produksie van nuwe verbindings of weens die opregulasie van bestaande metaboliese paaie. Die produksie van harige wortels en die vestiging daarvan in ‘n vloeibare sisteem tydens hierdie studie word beskou as ‘n belangrike stap na die opskalering van die kulture na bioreaktore. Hierdie wortels kan toekomstig tot die ontwikkeling van kulture met ‘n hoë produksie van gewenste metaboliete lei.
Larkindale, Jane. "Cell signalling in response to heat shock in Arabidopsis thaliana." Thesis, University of Oxford, 2001. http://ora.ox.ac.uk/objects/uuid:dc24f743-a69b-4aa9-92a4-fbdcbcff2bef.
Full textHe, Xuefeng. "Effect of class IId Bacteriocins: thuricin 17 and bacthuricin F4 on crops growth under optimal and abiotic stress conditions." Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66900.
Full textRÉSUMÉ Les bacteriocines sont les petits peptides produits par les bactéries qui ont des effets défavorables sur les microorganismes génétiquement proches de la souche productrice. Deux nouvelles bacteriocines de la classe IId, thuricin 17 et bacthuriocin F4, ont été isolées de bactéries présentes dans la rhizosphere et qui promouvoit la croissance des plantes (PGPR). Des études préalables ont démontré que ces deux bacteriocines peuvent promouvoir la croissance du soja. Mes résultats expérimentaux ont démontré que ces deux bacteriocines promouvoit la germination et l'émergence du maïs, du soja, du canola et du blé, mais n'ont pas d'effet sur l'orge, lorsque comparées aux contrôles sous des conditions optimales pour la croissance. Parmi les cultures testées, le maïs était le plus positivement affecté. Les expériences subséquentes sous stress abiotiques ont démontré que les deux bacteriocines ont augmenté l'émergence du maïs sous conditions de basse température, de salinité et de stress hydrique provoqué par le glycol de polyéthylène. Aussi, les expérimentations en champ ont démontré que le thuricin 17 peut promouvoir efficacement l'émergence du maïs dans le sud-ouest du Québec, où les températures printanières sont souvent fraîches.
Richards, Siân Louise. "The involvement of Arabidopsis thaliana Annexin 1 in abiotic stress response pathways." Thesis, University of Cambridge, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.648626.
Full textStork, Emily J. "INVASIVENESS AND INVASIBILITY IN THE DOLOMITE PRAIRIE PLANT COMMUNITY." OpenSIUC, 2012. https://opensiuc.lib.siu.edu/theses/839.
Full textXing, Yu. "Mitogen activated protein kinase cascades mediate the regulation of antioxidant enzymes under abiotic stresses in arabidopsis." HKBU Institutional Repository, 2007. http://repository.hkbu.edu.hk/etd_ra/834.
Full textDodt, Michael G. "Characterisation of root architectural responses of mungbean to water deficit." Thesis, Queensland University of Technology, 2017. https://eprints.qut.edu.au/115120/1/115120_6908519_michael_dodt_thesis.pdf.
Full textPimenta, Maiana Reis. "Functional characterization and regulation of abiotic stress-responsive genes (GmNAC081 and SbMATE) in plants." Universidade Federal de Viçosa, 2015. http://www.locus.ufv.br/handle/123456789/7525.
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Fundação de Amparo à Pesquisa do Estado de Minas Gerais
O início da senescência foliar é uma mudança do desenvolvimento altamente regulada, que é controlada por ambos genética e ambiente. A senescência é desencadeada por reprogramação massiva de transcrição, mas informações funcionais sobre os seus mecanismos reguladores subjacentes é limitada. No presente estudo, foi realizada uma análise funcional do fator de transcrição de soja (Glycine max) GmNAC081 induzido por estresse osmótico e do retículo endoplasmático (ER), durante senescência foliar natural, utilizando estudos de superexpressão e genética reversa. Linhagens superexpressando GmNAC081- exibiram floração e senescência foliar aceleradas, mas de outra forma se desenvolveram normalmente. A senescência foliar precoce de linhagens superexpressando GmNAC081 foi associada com maior perda de clorofila, deterioração fotossintética mais rápida e maior expressão de genes de codificação de enzimas hidrolíticas alvo de GmNAC081, incluindo a enzima de processamento vacuolar (VPE), uma executora da morte celular programada (PCD) desencadeada no vacúolo. Por outro lado, o silenciamento de GmNAC081 mediado por VIGS adia a senescência foliar e foi associado com reduções na perda de clorofila, a peroxidação lipídica e a expressão de alvos diretos de GmNAC081. Os estudos do promotor-repórter revelaram que o padrão de expressão GmNAC081 foi associado com a senescência, em folhas de soja. Nossos dados indicam que GmNAC081 é um regulador positivo da senescência dependente da idade e pode integrar as respostas de MCP induzida por estresse osmótico, do RE e senescência natural, completando o circuito regulamentar o GmNAC081 / VPE. Além de estressores ambientais, muitas espécies de plantas são sensíveis a concentrações micromolares de Al. Em sorgo, o gene de resistência ao alumínio é SbMATE, altamente expresso no ápice da radícula e codifica um transportador de membrana que pertencem à família MATE (multidrug and toxic compound extrusion family), que é responsável pelo efluxo citrato ativado por alumínio. Nesta espécie a região codificadora do gene de tolerância ao alumínio é identica entre cultivares tolerantes e sensíveis. Além de um polimorfismo encontrado no segundo íntron, elementos transponíveis do tipo MITE foram detectados na região promotora, sendo o número de repetições MITE positivamente relacionada com a tolerância. Neste trabalho, a análise in silico do promotor de SbMATE apresentou sequencias típicas de promotores eucarióticos assim como a presença de elementos cis regulatórios que conferem tolerância ao aluiminio em Arabidopsis. A ausência de atividade de promotores inteiros transformados em Arabidopsis sugerem a presença de elementos cis regulatórios negativos reprimindo a atividade em Arabidopsis ou ainda, a presença de silenciamento transcricional por RNA de interferência em Arabidopsis que não ocorre em Sorghum. Deleções do promotor, mostraram que os repressores estão localizados na sequência do elemento transponível já que na ausência deste elemento, o promotor passa a ser ativo em todas as partes da planta de forma independente da idade. A prospecção por fatores de transcrição que controlam a capacidade de resposta do gene SbMATE de Sorghum e a análise da interação entre prováveis transfatores com o promotor de SbMATE, foram realizadas através do sistema mono-hibrido em leveduras e evidenciaram a necessidade da obtenção de uma nova biblioteca de cDNA confeccionada por um kit mais adequado à esta planta, além da utilização de diferentes vetores de clonagem para as análises das iterações.
The onset of leaf senescence is a highly regulated developmental change that is controlled by both genetics and the environment. Senescence is triggered by massive transcriptional reprogramming, but functional information about its underlying regulatory mechanisms is limited. In the current investigation, we performed a functional analysis of the soybean (Glycine max) osmotic stress- and endoplasmic reticulum (ER) stress-induced NAC transcription factor GmNAC081 during natural leaf senescence using overexpression studies and reverse genetics. GmNAC081- overexpressing lines displayed accelerated flowering and leaf senescence but otherwise developed normally. The precocious leaf senescence of GmNAC081-overexpressing lines was associated with greater chlorophyll loss, faster photosynthetic decay and higher expression of hydrolytic enzyme- encoding GmNAC081 target genes, including the vacuolar processing enzyme (VPE), an executioner of vacuole-triggered programmed cell death (PCD). Conversely, VIGS-mediated silencing of GmNAC081 delayed leaf senescence and was associated with reductions in chlorophyll loss, lipid peroxidation and the expression of GmNAC081 direct targets. Promoter–reporter studies revealed that the expression pattern of GmNAC081 was associated with senescence in soybean leaves. Our data indicate that GmNAC081 is a positive regulator of age-dependent senescence and may integrate osmotic stress- and ER stress-induced PCD responses with natural leaf senescence thorough the GmNAC081/VPE regulatory circuit. In addition to environmental stressors, many plant species are sensitive to micromolar concentrations of Al. In sorghum, aluminum resistance SbMATE gene is highly expressed at the apex of the radicle and encodes a membrane transporter belonging to MATE family (multidrug and toxic Compound Extrusion family), which is responsible for the efflux activated aluminum citrate. In this species the coding region of the aluminum tolerance gene is identical between tolerant and sensitive cultivars. In a polymorphism is found in the second intron, the MITE type transposable elements were detected in the promoter region, the number of repetitions MITE positively related tolerance. In this work, the analysis in silico showed typical SbMATE promoter sequences of eukaryotic promoters, as well as the presence of cis regulatory elements that confer tolerance in Arabidopsis. The absence of whole promoter activity in transformed Arabidopsis suggesting the presence of negative regulatory cis- elements repressing the activity in Arabidopsis or the presence of transcriptional silencing by RNA interference in Arabidopsis does not occur in sorghum. Deletions promoter showed that the repressors are located in sequence as the transposable element in the absence of this element, the promoter becomes active in every part regardless of the age of plant form. Prospecting for transcription factors that control the responsiveness of SbMATE Sorghum gene and analysis of the interaction between likely transfatores with SbMATE promoter, were performed using mono-hybrid system in yeast and demonstrated the need for obtaining a new cDNA library made for a more appropriate for this plant kit, besides the use of different cloning vectors for analysis of iterations.
Zidenga, Tawanda. "Cyanide Metabolism, Postharvest Physiological Deterioration and Abiotic Stress Tolerance in Cassava (Manihot esculenta Crantz)." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1299018818.
Full textBilibana, Mawethu Pascoe. "Nitric oxide signaling and cysteine protease activity in the modulation of abiotic stress responses in soybean and maize." Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/5221.
Full textABSTRACT: Nitric Oxide (NO) is an essential bioregulatory molecule in plant growth, development, and tolerance against biotic and abiotic stresses. In legume root nodules, abiotic stresses impose restraint on metabolic capacity of bacteria and cause oxidative damage to cellular macromolecules, leading to inhibition of nitrogenase activity. In this study, the primary aim was to determine the influence of NO signaling on cysteine protease activity in soybean (Glycine. max [L] Merr) root nodules. Intact plants were treated with a NO donor, diethylenetriamine/nitric oxide adjunct (DETA/NO), 8-(4-chlorophenylthio)-[CPT]- cGMP, sorbitol and sodium chloride (NaCl). The root nodule cysteine protease activity was measured using the chromogenic substrate N-benzoil-L-p-nitroanilide (L-BAPNA). The results demonstrated NO as acting both as a protection against programmed cell death (PCD) at low exogenously applied NO concentrations, or as inducing PCD through regulating the cysteine proteases activity in root nodules when NO is applied at elevated concentrations. In the root nodules, the activity of cysteine protease is regulated either through cyclic guanosine monophosphate (cGMP)-dependent during abiotic stress or cGMP-independent pathways during normal root nodule development. The purpose of this research was to highlight the importance of NO in cell signaling and cysteine protease activity in legume root nodules. We also focused on the effect of abiotic stress on two maize genotypes as well as the influence of abiotic stress on cysteine protease activity in the abiotic stress-sensitive maize genotype than the tolerant genotype. The study suggests that cysteine protease activity can be used as early screen to identify abiotic stress-sensitive/tolerant maize genotype upon exposure to abiotic stress.
AFRIKAANSE OPSOMMING: Geen Afrikaanse opsomming beskikbaar.
National Research Foundation
Nohoesu, Oviavo. "Characterization of SABP2-Interacting Proteins (SIP) 428: an NAD+-Dependent Deacetylase Enzyme in Plant Abiotic Stress Signaling." Digital Commons @ East Tennessee State University, 2021. https://dc.etsu.edu/etd/3961.
Full textFrigerio, Sara. "Plant response to abiotic stress : analysis of changes in the photosynthetic apparatus at both gene and protein level." Aix-Marseille 2, 2008. http://www.theses.fr/2008AIX22076.
Full textDans la première partie du travail, il a été analysé le comportement des différents subunités appartenantes à la famille multigénique du Lhcb, dans réponse à des différentes conditions de croissance en maïs (Zea mays). La redondance de ces séquences, en effet, a suggéré un possible rôle spécifique de chaque produit génique dans la capture de la lumière et dans la photoprotection, sur la base des conditions environnementales. Les plantes ont été poussées en différentes conditions de lumière et température, pour ensuite en isoler les tylacoides au fin de les tester pour l’accumulation des protéines des antennes (Lhc). Des significatives différences ont été relevées dans les antennes, soit majeurs (LHCII) que mineurs, du Photosystème II (PSII) et, en détail, la température a joué un important rôle, puisque le rapport LHCII/antennes mineures a montré une augmentation avec la diminution de la température. Le froid, en effet, est un facteur de stress assez puissant, dès qu’il réduit énormément la vitesse de transport des électrons au niveau de l’oxydation du QH2 de la part du Cytb6f, en déterminant un excès de réduction du plastoquinone. Dans la deuxième partie de cette thèse, la régulation par les conditions environnementales des polypeptides qui constituent l'antenne photosynthétique a été analysée en employant un mutant d’orge (Hordeum vulgare), viridis zb63, qui manque du Photosystème I, ce qui produit la réduction du plastoquinone et mime une surexcitation chronique du Photosystème II. [. . . ]
Farias, Gabriel Castro. "Biometria e respostas fisiológicas de feijão-de-corda inoculado com fungos endofíticos dark septate sob estresse salino." reponame:Repositório Institucional da UFC, 2014. http://www.repositorio.ufc.br/handle/riufc/18602.
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With the increasing of areas degraded by soil salinization process, is necessary to increase of agricultural investments to be able to reach a production acceptable. In order to reduce such inputs, studies of microorganisms involved in the production process are becoming more constant. The objective of this study was to evaluate the associations between endophytic fungi Dark Septate and cowpea plants when irrigated with water of different salinities, analyzing biometrics, gas exchange, nutrient content and accumulation of organic solutes in the leaves. Cowpea plants were grow in containers of five liters under greenhouse conditions and subjected to four different electrical conductivity of irrigations water (1.2; 2.2; 3.6; 5.0 dS m-1). Were used for the inoculation strains B’2 and 21W and treatments were as follows: F1 – plants that were not inoculated; F2 – plants inoculated with strains 21W and F3 – plants inoculated with strain B’2. during the experiment was measured gas exchange and at the end of the experiment the plant were collected and determinate the leaf area, shoot dry mass, root dry mass, concentration of the foliar nutrients and organic solutes, and was made the determination colonization of roots by the fungus. The salinity caused significant reductions in biomass, leaf area and leaf gas exchange, however, the presence of the endophytic fungi provided a large tolerance to the adverse effects of salinity. There was a larger accumulation of calcium, sodium, clore and phosphorus in cowpea leaves with increasing salinity and decrease in the leaves of nitrogen and potassium. The presence of the fungus in the plant provided a foliar phosphorus and nitrogen.
Com o crescimento das áreas degradadas pelo processo de salinização dos solos se faz necessário o aumento do uso de insumos para que seja possível atingir uma produção aceitável. Visando a redução de tais insumos, estudos sobre microrganismos envolvidos no processo produtivo são cada vez mais constantes. O objetivo deste trabalho foi avaliar a resposta das associações entre fungos endofíticos Dark Septate e plantas de feijão-de-corda quando irrigado com águas de diferentes salinidades, analisando-se a biometria, troca gasosas, teores foliares de nutrientes e o acúmulo de solutos orgânicos nas folhas. As plantas de feijãode-corda foram cultivadas em vasos de 5 litros, sob condições de casa de vegetação e submetidas a quatro diferentes condutividades elétricas da água de irrigação (1,2; 2,2; 3,6 e 5,0 dS m-1). Para a inoculação foram utilizados as linhagens B’2 e 21W e os tratamentos foram os seguintes: F1 – plantas que não foram inoculadas; F2 – plantas inoculadas com a linhagem 21W e F3 – plantas inoculadas com a linhagem B'2. Durante a condução do experimento mediu-se as trocas gasosas e ao final do experimento as plantas foram coletadas e determinou-se a sua área foliar, massa seca da parte aérea, massa seca das raízes teores de nutrientes e solutos orgânicos foliares, bem como foi feita a determinação de colonização nas raízes pelo fungo. A salinidade provocou reduções significativas na biomassa, área foliar e trocas gasosas, contudo, a presença do fungo endofítico proporcionou uma maior tolerância aos efeitos negativos da salinidade. Houve um maior acúmulo de cálcio, sódio, cloro e fósforo em folhas de feijão-de-corda com o aumento da salinidade e uma diminuição dos teores de nitrogênio e potássio. A presença do fungo na planta proporcionou maior teor foliar de fósforo e nitrogênio.
Farias, Gabriel Castro. "Biometric and physiological responses of bean inoculated with Dark septate endophytic fungi under salt stress." Universidade Federal do CearÃ, 2014. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=13534.
Full textWith the increasing of areas degraded by soil salinization process, is necessary to increase of agricultural investments to be able to reach a production acceptable. In order to reduce such inputs, studies of microorganisms involved in the production process are becoming more constant. The objective of this study was to evaluate the associations between endophytic fungi Dark Septate and cowpea plants when irrigated with water of different salinities, analyzing biometrics, gas exchange, nutrient content and accumulation of organic solutes in the leaves. Cowpea plants were grow in containers of five liters under greenhouse conditions and subjected to four different electrical conductivity of irrigations water (1.2; 2.2; 3.6; 5.0 dS m-1). Were used for the inoculation strains Bâ2 and 21W and treatments were as follows: F1 â plants that were not inoculated; F2 â plants inoculated with strains 21W and F3 â plants inoculated with strain Bâ2. during the experiment was measured gas exchange and at the end of the experiment the plant were collected and determinate the leaf area, shoot dry mass, root dry mass, concentration of the foliar nutrients and organic solutes, and was made the determination colonization of roots by the fungus. The salinity caused significant reductions in biomass, leaf area and leaf gas exchange, however, the presence of the endophytic fungi provided a large tolerance to the adverse effects of salinity. There was a larger accumulation of calcium, sodium, clore and phosphorus in cowpea leaves with increasing salinity and decrease in the leaves of nitrogen and potassium. The presence of the fungus in the plant provided a foliar phosphorus and nitrogen.
With the increasing of areas degraded by soil salinization process, is necessary to increase of agricultural investments to be able to reach a production acceptable. In order to reduce such inputs, studies of microorganisms involved in the production process are becoming more constant. The objective of this study was to evaluate the associations between endophytic fungi Dark Septate and cowpea plants when irrigated with water of different salinities, analyzing biometrics, gas exchange, nutrient content and accumulation of organic solutes in the leaves. Cowpea plants were grow in containers of five liters under greenhouse conditions and subjected to four different electrical conductivity of irrigations water (1.2; 2.2; 3.6; 5.0 dS m-1). Were used for the inoculation strains Bâ2 and 21W and treatments were as follows: F1 â plants that were not inoculated; F2 â plants inoculated with strains 21W and F3 â plants inoculated with strain Bâ2. during the experiment was measured gas exchange and at the end of the experiment the plant were collected and determinate the leaf area, shoot dry mass, root dry mass, concentration of the foliar nutrients and organic solutes, and was made the determination colonization of roots by the fungus. The salinity caused significant reductions in biomass, leaf area and leaf gas exchange, however, the presence of the endophytic fungi provided a large tolerance to the adverse effects of salinity. There was a larger accumulation of calcium, sodium, clore and phosphorus in cowpea leaves with increasing salinity and decrease in the leaves of nitrogen and potassium. The presence of the fungus in the plant provided a foliar phosphorus and nitrogen.
Lo, Cicero Luca. "Generation of CsGSTUs over-expressing tobacco plants and their role in abiotic and biotic stress tolerance." Doctoral thesis, Università di Catania, 2014. http://hdl.handle.net/10761/1574.
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