Dissertations / Theses on the topic 'Salinity tolerance'
To see the other types of publications on this topic, follow the link: Salinity tolerance.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Salinity tolerance.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Elmezoghi, Saleh Mohamed. "Physiology of salinity tolerance in maize." Thesis, University of Liverpool, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.433774.
Full text
2
Babagolzadeh, Ali. "Salinity tolerance in seven Trifolium species." Thesis, University of Liverpool, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367195.
Full text
3
Hossain, Mohammad Rashed. "Salinity tolerance and transcriptomics in rice." Thesis, University of Birmingham, 2014. http://etheses.bham.ac.uk//id/eprint/5092/.
Full textAbstract:
Morpho-physiological characterization and whole genome transcript profiling of rice genotypes that belongs to sub-species Indica, Japonica and wild relatives were carried out under salt stress. The existence of qualitatively different mechanisms of salt tolerance across the genotypes was identified. Multivariate analysis was applied to categorize the genotypes according to their level of tolerance. Modified SAM analysis elucidated the trait specific expression of genome wide transcripts. Gene ontology enrichment analysis identified the genes involved in different molecular functions such as signal transduction, transcription factor and ion homeostasis etc. Gene network analysis identified the regulatory network of genes that are active in different tissues. The differential expression of transcripts of four tolerant and two susceptible Indica genotypes under stress were further analysed. The candidate genes for different biological processes and molecular functions are identified and discussed. Highly induced stimulus responsive gene Os01g0159600 (OsLEA1a) and Os05g0382200 (Nhx) can be mentioned for instance. The differentially expressed genes that are located within the salt stress related QTLs were also identified. The transcriptomics data were also used to predict the salinity tolerance of genotypes using OSC-PLSDA model. The combined physiological and transcriptomic approach of this study gives a complementary whole organism assessment of plants responses to salt stress.
4
Schuch, Ursula K., and Jack J. Kelly. "Salinity Tolerance of Cacti and Succulents." College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2008. http://hdl.handle.net/10150/216639.
Full textAbstract:
The salinity tolerance of golden barrel cactus (Echinocactus grusonii), ocotillo (Fouquieria splendens), saguaro cactus (Carnegiea gigantea), and Gentry’s agave (Agave parryi truncata) was tested. Plants were irrigated with a solution of EC 0.6, 5.0, 10.0, and 15.0 dS/m. Duration of treatments were 18 weeks for saguaro and 26 weeks for the other three species. In general, fresh weight, dry weight, and moisture content decreased with increasing salinity levels, with the exception of saguaro dry weight which was not affected by the treatments, and ocotillo moisture content which increased with increasing salinity. Runoff was collected three times during the experiment and indicated that ion uptake was higher for barrel cactus than the other three species. EC of runoff averaged for all dates and species showed an increase of 17%, 54%, 46%, and 64% over the salinity treatment solutions of 0.6, 5.0, 10.0, and 15.0 dS/m, respectively.
5
Hendawy, Salah El-Sayed el. "Salinity tolerance in Egyptian spring wheat genotypes." [S.l. : s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=972317627.
Full text
6
Kwon, Taek-Ryoun. "Physiological studies of salinity tolerance in Brassica species." Thesis, Coventry University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361653.
Full text
7
Buya, J. K. "The genetics of salinity tolerance in Tilapia species." Thesis, Swansea University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.636193.
Full textAbstract:
Path coefficients were applied to estimate the amount of variation each physiological factor determines in the serum water content (SEWCON) or time-to-succumb (TS). Each estimate was used to reconstitute its own mean. In all cases, the re-constructed variables exhibited a higher value of VG/VP than in the original. This infers the expression of genetic variability masked by the composite action of many gene differences on the trait (Mather and Harrison 1949). VG/VP was related to neither the correlation or regression between groups. Correlation estimates differed from their intra-class correlations (rI). ANOVA values of VG/VP were similar to those of rI, which estimates the amount of genetic variability in the trait (Falconer 1981). VG/VP estimates from repeatability are not about how "repeatable" measures are (Falconer 1981), but rather the degree to which individuals differ from each other, the individuality (I). Both being standardized values (Bentsen 1994), the individuality readily translates into the heredity (h), the degree to which an individual's phenotype is determined by additive genetic factors. This idea was developed by Wright (1911) to define the heritability (h2); where hPPx ½hOP = ½h2 and hPP, the covariance between additive genetic and phenotypic values (COV (Ai, Pj)) which is also the covariance between parents and their respective family genotypic values (CO (giP, gjF)) (Mather and Harrison 1949). This is the additive degree of divergence (d), between parents (Bentsen 1994). When this quantity is estimated from half-siblings it has a magnitude of ¼h. The offspring-parent path (hOP), is the correlation of parent additive and offspring phenotypic values, (COV(AiP, PjO)). Its value is ½h. A domestication selection programme for tilapia species is proposed, where several lines of known genetic differences are generated to aid improvement programs through reciprocal recurrent selection (RRS).
8
Møller, Inge Skrumsager. "Na⁺ exclusion and salinity tolerance in Arabidopsis thaliana." Thesis, University of Cambridge, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.612521.
Full text
9
Schrader, Stephanie EllaJean, and Stephanie EllaJean Schrader. "Salinity Tolerance of Lettuce Cultivars in Controlled Environment." Thesis, The University of Arizona, 2017. http://hdl.handle.net/10150/624098.
Full textAbstract:
The specific objectives of this study were to determine the effects of increasing salinity on growth, crop quality, and physiological parameters of different lettuce (Lactuca sativa L.) cultivars grown either in a hydroponic system or in soil and subjected to irrigation water of varying salinity levels. Two trials were conducted in winter 2016 and summer 2016 in a greenhouse using a hydroponic system for the cultivation of three lettuce cultivars. 'Romaine del Sol', Leaf Lettuce 'Bergams Green' and 'Green Leaf Lettuce' were exposed to irrigation water with increasing salinity (2.1, 3.6, 5.1, and 6.6 dS/m) by supplementing the nutrient solution (2.1 dS/m) with a combination of 2:1 NaCl and CaCl2. Lettuce head height, diameter, leaf number, shoot and root dry weight were not impacted by increasing salinity. Similarly, osmotic potential, transpiration and leaf temperature were not affected. However, head fresh weight and water content were reduced at the higher salinity levels compared to the control in the second trial. A third greenhouse trial was conducted in winter 2017 with 'Romaine del Sol' and 'Green Leaf Lettuce' cultivars grown in a hydroponics system or in containers with soil to determine tolerance to increasing salinity in different substrates. Head height, diameter, and shoot dry mass decreased at the two highest salinity levels at the final harvest. When plants were smaller, salinity had no effect on these variables. Fresh weight, water content, and leaf number decreased with increasing salinity at final harvest for both cultivars however, osmotic potential of both cultivars was not affected by salinity or substrate throughout the study. An informal taste test found that the leaves from the two highest levels of salinity from both cultivars were inedible because of a salty and bitter taste. Mineral concentration of sodium and chloride in ‘Romaine’ and 'Green Leaf Lettuce' increased as salinity levels increased, and plants of both cultivars grown in soil had greater concentrations of both elements when compared to hydroponics. 'Romaine' and 'Green Leaf Lettuce' are more tolerant to salinity than previously reported in other lettuce cultivars, and the physiological variables measured showed little changes in response to increasing salinity. Although lettuce grown at 5.1 dS/m and 6.6 dS/m was marginally acceptable by size standards, the lack of head formation in ‘Romaine del Sol’, and the unfavorable taste of both cultivars would render them unmarketable.
10
Hawks, Austin McCoy. "Salinity Inventory and Tolerance Screening in Utah Agriculture." DigitalCommons@USU, 2009. https://digitalcommons.usu.edu/etd/546.
Full textAbstract:
Soil salinity, a yield-limiting condition, has plagued crop production for centuries by reducing crop productivity. Research has introduced methods for successfully managing soil salinity. This research discusses the adaptation of established management methods to create new soil salinity management techniques. One adapted technique is an automated crop screening apparatus. A new design was created and successfully used in rapidly screening two strawberry cultivars to determine their tolerance to salinity. Screening crops and determining their tolerance to yield-limiting conditions are essential in managing soil salinity. Another salinity management tool used in this research was electromagnetic induction (EMI). EMI was used to complete a basin-scale inventory over an 18,000 ha study area in Cache County, Utah. The data obtained during the inventory were used to create EMI calibration models and a basin-scale map showing the spatial distribution of apparent soil electrical conductivity (ECa). These new methods for crop tolerance screenings and basin-scale salinity inventories will assist in successfully managing soil salinity and decrease its effect on the global food supply.
11
Dashti, Sayyed Aliasghar. "Physiological and genetic aspects of salinity tolerance in sorghum." Thesis, University of Liverpool, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.368871.
Full text
12
Foroozanfar, Maryam. "Genetic control of tolerance to salinity in Medicago truncatula." Thesis, Toulouse, INPT, 2013. http://www.theses.fr/2013INPT0035/document.
Full textAbstract:
Parmi les contraintes abiotiques la salinité est considérée comme un problème majeur, qui affecte le fonctionnement des plantes, en particulier leur croissance et leur rendement. Afin d’étudier le contrôle génétique de la tolérance à la salinité chez Medicago truncatula, plante modèle de la famille des légumineuses, deux expérimentations ont été réalisées. La première expérimentation visait à étudier l’effet de la contrainte saline sur différents paramètres morpho-physiologiques pour un panel de génotypes de M. truncatula afin de déterminer les traits de phénotypage pour la tolérance à la salinité. Les génotypes A17, TN1.11, DZA315.16, A20, TN1.12 et F83005.5 ont été sélectionnés parmi des lignées originaires de différents pays méditerranéens, qui ont été déjà séquencées (http://www1.montpellierinra.fr/BRC-MTR/mauguio/mauguio.php). Les génotypes ont été étudiés sous 6 traitements salins (0, 30, 60, 90,120 et 150 mM NaCl) dans un essai factoriel sous forme de blocs complets aléatoires en trois répétitions. L’analyse de la variance montre des différences significatives entre les niveaux de salinité et une interaction entre les génotypes et les traitements salins concernant la plupart des caractères étudiés. Le génotype « DZA315.16 » présente les valeurs les plus importantes concernant les effets principaux pour les caractères morphologiques alors que « TN1.11 » présente les valeurs les plus faibles. La projection verticale de la surface foliaire de la plante (Leaf Area=LA), significativement corrélée à la biomasse des plantes, apparaît comme un trait d’intérêt pour le phénotypage de la tolérance à la salinité. La concentration saline la mieux adaptée pour démontrer les différences parmi les lignes étudiées se situe entre 90 et 120 mM NaCl. Le génotype « TN1.11 » contrairement à « DZA315.16 » et à « Jemalong-A17 » présente un maintien de la surface foliaire de la plante en réponse à la salinité. Pour la deuxième expérimentation, une population de cent lignées recombinantes (Recombinant Inbred Lines=RILs) produite par le croisement entre « TN1.11 » et « Jemalong-A17 » a été retenue pour l’analyse du contrôle génétique de la tolérance à la salinité. Les RILs ont été développés par la méthode de descendant mono graines (Single Seed descent= SSD) jusqu’ à la génération F6 à l’INP-ENSAT, France. Le plan d’experimentation est « Spli plots » , sous forme de blocs randomisés avec trois répétitions et deux conditions : traitement salin (100 mM NaCl) et témoin (eau). L’expérience a été menée pour déterminer la variabilité génétique et pour identifier les QTLs contrôlant les caractères morphologiques et physiologiques chez la population des lignées recombinantes (RILs). L’analyse de la variance a montré une large variation génétique et une ségrégation transgressive pour les caractères étudiés. La différence entre la moyenne des RILs et la moyenne de leurs parents n’est pas significative concernant tous les caractères étudiés dans les deux conditions, ce qui montre que les RILs utilisées dans notre expérimentation sont représentatives de toutes les lignées recombinantes possibles du croisement « TN1.11 x Jemalong-A17 ». 21 QTLs ont été détectés dans la condition témoin et 19 QTLs ont été identifiés sous contrainte saline (100 mM NaCl). Le pourcentage de la variance phénotypique expliqué par les QTLs varie entre 4.60% et 23.01%. Certains de ces QTLs sont spécifiques à la condition saline, ce qui démontre l’existence du contrôle génétique de la tolérance à la salinité chez M. truncatula ; tandis que les autres ne sont pas spécifiques et contrôlent un même caractère dans les deux conditions. Des QTLs superposés concernant différents caractères ont été aussi observés. Les résultats fournissent des informations importantes en vue de futures analyses fonctionnelles de la tolérance à la salinité chez M.truncatula et pour d’autres espèces voisinesAmong abiotic stresses salinity is considered as a serious problem affecting plant functions especially growth and yield. In order to study the genetic control of salt stress in the model legume Medicago truncatula, two experiments were performed. The first experiment was conducted to study the effect of salt stress on some morpho-physiological parameters in M. truncatula genotypes and to determine the eventual use of some traits as tolerance criteria. Genotypes including A17, TN1.11, DZA315.16, A20, TN1.12 and F83005.5 are selected through a sequenced lines collection (http://www1.montpellierinra.fr/BRC-MTR/mauguio/mauguio.php) which are originated from different Mediterranean countries. Genotypes were studied under 6 salinity treatments (0, 30, 60, 90,120 and 150 mM NaCl) in a factorial design based on randomized complete blocks with three replications. Analysis of variance show significant differences among genotypes, salinity levels and interaction between genotypes and salt treatments for most of studied traits. “DZA315.16” genotype presents the highest main effect values for morphological traits whereas”TN1.11” has low values. Vertically projected leaf area (LA); show the highest variability through all studied salt concentrations. The best concentration to find differences between parental lines is 90 to 120 mM Nacl. A segregating population of recombinant inbred lines (100 RILs) of M.truncatula derived from a cross between TN1.11 and Jemalong-A17 was used for the second experiment. RILs were developed by single-seed descent until F6 generation at the INP-ENSAT, France. The experiment was undertaken to determine the genetic variability and to identify QTLs controlling several traits related to plant growth and physiology, in the population of recombinant inbred lines (RILs). Analyses of variance showed a large genetic variation and transgressive segregation for the traits studied. The difference between the mean of RILs and the mean of their parents was not significant for all of the traits in both conditions, showing that the RILs used in our experiment are representative of the possible recombinant lines from the cross TN1.11 x A17. A total of 21 QTLs were detected under control and 19 QTLs were identified under 100mM salt stress conditions. The percentage of total phenotypic variance explained by the QTLs ranged from 4.60% to 23.01%. Some of the QTLs were specific for one condition, demonstrating that the genetic control of a traits differed under control and salt stress conditions. Some others are non-specific and control a trait in both conditions. Overlapping QTLs for different traits were also observed. The results provide important information for further functional analysis of salt tolerance in M. truncatula
13
Yichie, Yoav. "Salinity tolerance of wild rice accessions from northern Australia." Thesis, The University of Sydney, 2020. https://hdl.handle.net/2123/21824.
Full textAbstract:
Salinity is a limiting factor for rice production globally. Cultivated rice (Oryza sativa) is highly sensitive to salinity. I studied the salt tolerance of Australian wild Oryza species to identify diversity in salt tolerance and target genes for molecular breeding. I first performed two physiological salt-screening experiments on nine wild accessions from a range of sites across northern Australia for growth responses to NaCl up to 120 mM. Screens at 40–100 mM NaCl revealed considerable variation in salt sensitivity in accessions of O. meridionalis (Om) and O. australiensis (Oa). Growth of an Oa accession (Oa-VR) was especially salt tolerant compared with other accessions, including a salt-tolerant ‘control’ of O. sativa, Pokkali. At 80 mM NaCl, the shoot Na+/K+ ratio was the lowest in Oa-VR and Pokkali. An image-based screen was then conducted to quantify plant responses to different levels of salinity over 30 d. This revealed striking levels of salt tolerance supporting the earlier screens. Root membrane fractions of two Oa accessions with contrasting salinity tolerance (Oa-VR and Oa-D) were subjected to quantitative proteomics to identify candidate proteins contributing to salt tolerance. Plants were exposed to 80 mM NaCl for 30 d. Root proteins were analysed via tandem mass tag (TMT) labelling. Gene Ontology (GO) annotations of differentially abundant proteins showed those in the categories ‘metabolic process’, ‘transport’ and ‘transmembrane transporter’ were highly responsive to salt. mRNA quantification validated the elevated protein abundances of a monosaccharide transporter and a VAMP-like antiporter in the salt-tolerant genotype. The importance of these two proteins was confirmed by measuring growth responses to salt in two yeast mutants in which genes homologous to those encoding these two proteins in rice had been knocked out. This study provided insights into physiological and molecular mechanisms of salinity responses in Australian native rice species.
14
Aloy, i. Lleonart Merce. "Leaf ion concentrations and salt tolerance in barley." Thesis, Bangor University, 1994. https://research.bangor.ac.uk/portal/en/theses/leaf-ion-concentrations-and-salt-tolerance-in-barley(b9c4ca87-24dd-424d-b5f6-7c8f24c3a886).html.
Full textAbstract:
Breeding and selection for salt tolerance has been limited because of the large heterogeneity of natural saline soils and the lack of efficient criteria for measuring salt tolerance. Regulation of salt balances in leaves is an important aspect of salt tolerance. This work analyses the relationship between leaf ion concentrations and salt tolerance with the aim of using these traits as indicators of salt tolerance. This is done both in solution culture (hydroponics) and field trials (sprinkler irrigation with saline water). Varieties were found to differ in the amounts of ions accumulated in their leaves. However, these differences did not relate directly with their level of salt tolerance. The lack of correlation was partly due to difficulties in estimating salt tolerance in the field. Also, the Triple Line Sprinkler system (TLS) used in the field experiments posed several problems, the most important ones being related to direct ion absorption by the leaves. The high concentrations of CaC12 (in addition to NaCl) used in the irrigation water added a further complication. In hydroponic experiments, a minimum of 2 mol in-' Ce' was enough to prevent an indiscriminate entry of Na' and to ameliorate the growth inhibition of plants growing at 200 mol in-' NaCl. Higher Caý' concentrations (50 mol in-' CaCl2) reduced even more the concentrations of Na' in leaves without significantly affecting growth. At these high levels of CaCl2 any toxic effect was probably caused by high Clconcentrations.
15
Israelsen, Karl R. "Herbicide, Salinity, and Flooding Tolerance of Foxtail Barley (Hordeum jubatum L.) and Desirable Pasture Grasses." DigitalCommons@USU, 2009. https://digitalcommons.usu.edu/etd/519.
Full textAbstract:
Research trials performed in the greenhouse compared the tolerance and response of Hordeum jubatum and desirable pasture grass species to herbicides, salinity, and flooding. Desirable grass species used in this study included: `Fawn' tall fescue (Festuca arundinaceae), `Garrison' creeping foxtail (Alopecurus arundinaceus), `Palaton' reed canarygrass (Phalaris arundinacea), `Climax' timothy (Phleum pratense), `Alkar' tall wheatgrass (Thinopyrum ponticum), `Potomac' orchardgrass (Dactylis glomerata), and `Mustang' altai wildrye (Leymus angustus). Tolerance to herbicides, salinity, and flooding varied significantly among grass species. Herbicide tolerance was tested using four herbicides at five rates each. The herbicides used were imazapic (Plateau), propoxycarbazone (Olympus), sulfosulfuron (Outrider), and flucarbazone (Everest) at rates of 0, 10, 25, 50, 100, and 200 g ha-1. Foxtail barley was least tolerant of sulfosulfuron and propoxycarbazone. Tall fescue, creeping foxtail, and reed canarygrass were susceptible to all the herbicides tested. Timothy and foxtail barley were moderately tolerant while tall wheatgrass exhibited the greatest tolerance to flucarbazone. Orchardgrass was most tolerant to propoxycarbazone. Salinity tolerance was determined by exposing grasses to increasing electrical conductivity (EC) over time. Reed canarygrass and timothy were most susceptible to salinity. Orchardgrass, creeping foxtail, and tall fescue were moderately tolerant of salinity. Foxtail barley, altai wildrye, and tall wheatgrass exhibited the highest tolerances to salinity, and continued to persist at the highest EC levels tested. Flooding tolerance was determined by flooding grasses in 18 cm of water for 2, 4, 6, and 8 weeks. Grasses that were able to extend above the water surface survived, whereas plants that failed to extend beyond the water surface experienced higher mortality rates.
16
Noori, Seyed Ahmad Sadat. "Salinity tolerance in wheat (Triticum aestivum L.) and its relatives." Thesis, University of Liverpool, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367305.
Full text
17
Garthwaite, Alaina Jane. "Physiological traits associated with tolerance to salinity and waterlogging in the genus 'Hordeum' /." University of Western Australia, 2005. http://theses.library.uwa.edu.au/adt-WU2005.0133.
Full textAbstract:
Wild Hordeum species, from the four genome groups of X, H, I and Y, were assessed for physiological traits associated with tolerance to salinity and waterlogging. When grown in saline conditions, a number of wild Hordeum species had exceptional ‘exclusion’ of Na+ and Cl- from the young leaves, and also maintained tissue K+ concentrations, compared with Hordum vulgare ssp. vulgare (cv. ‘Golf’). For example, at 150 mol m-3 NaCl, the K+:Na+ in youngest, fully expanded leaf blades of wild Hordeum species averaged 5.2, compared with 0.8 in H. vulgare. H. marinum was more salt tolerant than H. vulgare, with a relative growth rate 30% higher than H. vulgare at 150 mol m-3 NaCl. At 300 mol m-3 NaCl, glycinebetaine plus proline contributed to 15% of πsap in expanding leaf blades of H. marinum, compared with 8% in H. vulgare. When grown in stagnant conditions, 16 accessions (approximately half of those evaluated) formed a barrier to radial O2 loss (ROL) in basal zones of adventitious roots. In the Triticeae, this trait had previously only been described in one species, H. marinum. The barrier to ROL occurred only in accessions from wetland or intermediate habitats, and was also related to genome type, being present in accessions with the X or the H genome (Hordeum vulgare has the I genome). In stagnant conditions, aerenchyma formed was, on average; 22% in accessions with the X genome; 19% in those with the H genome; and 15 and 16% in those with the I or the Y genomes, respectively. The combination of a barrier to ROL and aerenchyma enhances longitudinal O2 movement in adventitious roots, permitting roots to penetrate deeper into anaerobic substrates. In H. marinum, induction of the barrier to ROL was associated with a 97% reduction in apparent O2 diffusivity across the external layers of the basal zones of roots, compared with near the root tip. The barrier results from physical resistance to radial O2 movement, although when roots were cooled to suppress respiration some additional leakage of O2 was detected, indicating respiration also contributes to the low rates of ROL from the basal regions of roots. Low radial O2 permeability in the roots of stagnantly-treated H. marinum was associated with secondary thickening, putatively lignin or suberin deposits, in the hypodermis. These changes in root structure, however, did not influence root hydraulic conductivity, assessed for individual adventitious roots and whole root systems. Thus, diversity amongst Hordeum species in expression of traits for tolerance to waterlogging (an inducible barrier to ROL and aerenchyma) and salinity (Na+ and Cl- ‘exclusion’) were documented in this study. Traits for root aeration did not compromise the capacity of roots to take up water, presumably being of importance for growth in soils with fluctuating water levels (i.e. wet/dry cycles). The high degree of salinity tolerance in several Hordeum species, and especially in H. marinum, is consistent with field observations that these species occur in salt affected areas
18
Semikhodskii, Andrei G. "Mapping quantitative traits for salinity responses in wheat (Triticum aestivum L.)." Thesis, University of East Anglia, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302054.
Full text
19
Scott, A. M. "Salinity and the growth of Crithmum maritimum and Lavatera arborea." Thesis, Lancaster University, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.371066.
Full text
20
Gillespie, Trudi. "Genetic variation in salt tolerance of four African Acacia species." Thesis, Bangor University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327422.
Full text
21
Hauer, Gwen. "Salinity Tolerance of Naked Amoebae from Freshwater, Marine, and Hypersaline Environments." NSUWorks, 2003. http://nsuworks.nova.edu/occ_stuetd/118.
Full textAbstract:
The current study examines salinity tolerance in naked amoebae. A biodiversity study was conducted in the Salton Sea, an inland lake in southern California, with an average salinity of 44 ‰. Amoebae were also collected from hypersaline ponds around the perimeter of the Sea where salinities averaged 160 ‰. A total of 45 species of amoebae were isolated, about one third of which were new to science. One Salton Sea species, Platyamoeba pseudovannellida n.sp. was found to survived over the range 0 - 150 ‰. A first estimate of abundances of amoebae in the Sea showed that densities could reach 237,120 cells L-1. Many of the isolates were observed to consume cyanobacteria and algae suggesting that amoebae are important regulators of blooms in the Sea, although this was not tested experimentally. Samples from the intertidal zone of a beach, a habitat also subject to salinity fluctuations, provided the first abundances of naked amoebae in sand. Densities ranged between 181 and 8473 amoebae cm-3, again suggesting that amoebae are important micrograzers in this challenging environment. From the aforementioned studies, 6 clones of amoebae were isolated for salinity tolerance experiments (2 marine beach isolates, 2 Salton Sea isolates, and 2 hypersaline pond isolates). A seventh clone, Acanthamoeba polyphaga, a common freshwater/soil amoeba was obtained from the Culture Collection of Algae and Protozoa (CCAP). The experiments compared the effects of gradual versus no acclimatization and used growth rate and culture yield as indices of effect. Generally, amoebae were tolerant over a wide range of salinity conditions and were not markedly influenced by pre-conditioning to salinity regimes. Acanthamoeba grew in 0 -12 ‰, marine clones 2 and 3 in 0 - 110 ‰, Salton Sea clones 4 and 5 in 0 - 150 ‰, and the hypersaline clones 6 and 7 in 0 - 270 ‰ salt. The results suggest that most amoebae are essentially unaffected in terms of growth and yield by moderate and severe salinity changes. The survival and activity of large populations of amoebae in sites subject to salinity challenges suggest that they should be considered in future studies designed to understand their as yet undefined ecological role.
22
Williams, Mark Donald. "Salinity tolerance of small fishes from the Murray-Darling river system /." Title page, contents and conclusions only, 1987. http://web4.library.adelaide.edu.au/theses/09SB/09sbw725.pdf.
Full text
23
Gallagher, Zoë Sydney Wilson. "The development of salinity tolerance in juvenile pink salmon (Oncorhynchus gorbuscha)." Thesis, University of British Columbia, 2011. http://hdl.handle.net/2429/39076.
Full textAbstract:
Following yolk-sac absorption and gravel emergence pink salmon (Oncorhynchus gorbuscha) migrate into seawater (SW) at as small as 0.2 g. This life-history strategy is in contrast with most anadromous salmonid species that generally spend 1-2 years growing in fresh water (FW) and physiologically preparing for life in SW before they migrate to SW as smolts. This study characterized for the first time the ontogeny of SW tolerance in pink salmon around the period of yolk-sac absorption. Post-hatch juvenile pink salmon were either held in FW for 26 weeks or transferred to SW every two weeks for 20 weeks to follow % survival, whole body (WB) Na+ and water content, as well as changes in wet and dry mass, gill Na+K+ATPase (NKA) activity and α1a and α1b mRNA isoform expression. An increase in gill NKA activity and the ratio of the α1b/α1a isoform expression, a plateau in WB water and Na+ levels, and the switch from catabolic to anabolic growth were all observed at the time of yolk-sac absorption in fish retained in freshwater. At this time, morbidity following subsequent SW transfer fell to 0% from a high of 100% for newly hatched alevins, but then rose to 25% in older fry, suggesting that a window of increased salinity tolerance exists for pink salmon at the time of yolk-sac absorption. This proposed window of SW tolerance is similar to the smolt window that has been identified for other salmonids; but in pink salmon appears to be endogenously mediated, as fish were reared under constant (12L:12D) photoperiod and at 5˚C throughout the study. Moreover, smoltification is incomplete since transfer to SW further elevated gill NKA activity and increased gill NKA α1b/α1α isoform expression ratio 8-fold at yolk-sac absorption. Thus, even the most SW-tolerant fish were not fully prepared for SW before entry, but responded directly to SW by further increasing hypo-osmoregulatory ability. This study filled the previously existing void of knowledge regarding the acquisition of salinity tolerance in juvenile pink salmon.
24
Howladar, Saad Mohammed. "Effects of salicylic acid on salinity tolerance of wheat (Triticum aestivum)." Thesis, University of Reading, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.553172.
Full textAbstract:
Four glasshouse experiments examined salinity stress and tolerance in wheat. The first experiment examined the responses of three wheat cultivars from Saudi Arabia (Local wheat, West bread and Yecora Rojo) and two UK wheat cultivars (Paragon and Belvoir) to different levels of salinity (Tap water, 25, 50, 100, 150 and 200 mM NaCI). In the second experiment, Yecora Rojo and Paragon were selected to test whether improved wheat tolerance to salinity could be obtained by applying exogenous Salicylic acid (0, 0.5, 1 and 2 mM SA) via priming seeds for 6 hours. The third experiment further tested the effect of SA on tolerance to salinity with SA applied through seed soaking for 6h and 24h. Two salinity tolerant cultivars (S24 and Sakha 93) were included for comparison. The fourth experiment compared the effect of SA applied by seed soaking (6h) or by foliar spray. In all experiments, saline conditions gave significant declines in wheat growth parameters, gas exchange, yield and yield components with increases in salinity concentration, whereas protein and chlorophyll content increased. Cultivar Paragon grew significantly better than cultivar Yecora Rojo in non-saline conditions but not under salinity stress. Treating wheat with SA produced only a minor improvement in growth parameters, yield and yield components under salinity stress. Compared to salt tolerant cultivars, Paragon showed significant response to SA in most variables. The influence of SA depended on genotype, plant stage and SA concentration more than soaking time and application method with 0.5 and 1 mM SA concentrations being the most effective. SA mitigates but does not prevent salinity impacts and has a dual function which can give positive or negative effects under salinity stress.
25
Arvin, Javad. "Tissue culture in potatoes and in vitro selection for salinity tolerance." Thesis, University of Reading, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315388.
Full text
26
Robinson, David Lowell 1955. "RECURRENT SELECTION FOR GERMINATION SALT TOLERANCE IN ALFALFA (SALINITY, FORAGES, BREEDING)." Thesis, The University of Arizona, 1986. http://hdl.handle.net/10150/277015.
Full text
27
Jayakody, Ramani Renuka Perera. "Stomatal mechanisms and their contribution to salinity tolerance in Aster tripolium L." Thesis, Lancaster University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240550.
Full text
28
Gxaba, Nomagugu. "The effect of exogenous growth regulators on salinity tolerance in Erucastrum strigosum." University of the Western Cape, 2003. http://hdl.handle.net/11394/8268.
Full textAbstract:
Magister Scientiae (Biodiversity and Conservation Biology) - MSc (Biodiv and Cons Biol)Randomized block experiments were conducted to examine the putative amelioratory effects of kinetin or gibberellic acid at concentrations (0, 4, 12.5, 40, and 125 μM) in Erucastrum strigosum plants subjected to a salinity series (0, 100, 200, 300, and 400 mM NaCl) in the greenhouse. When the highest salinity concentration (increased stepwise) was reached, growth effects in relation to water and cation content of the plants were evaluated. Growth and water content were reduced progressively with salinity treatments. Na+ concentration accumulated with salinity treatments to levels that were much higher than that of other cations (K+, Ca2+ and Mg2+) in both organs. However, it is noteworthy that Na+ distribution was more in shoots than in roots. In kinetin treated plants, shoot growth decreased whilst root growth increased with moderate hormonal treatments.
29
Carregosa, Vanessa Silva. "Tolerance and response of clams in Ria de Aveiro to salinity changes." Master's thesis, Universidade de Aveiro, 2014. http://hdl.handle.net/10773/13424.
Full textAbstract:
Mestrado em Biologia MarinhaUnlike the concern that has been growing in relation to the impacts of contamination in marine benthic populations, the responses of aquatic organisms to natural alterations, namely changes in salinity, have received little attention. In fact, salinity is one of the dominant environmental factors that most affect marine bivalves, limiting their spatial distribution in the environment. Tide combined with fresh water inputs, from rivers or heavy rainy periods, and extreme dry seasons can dramatically alter the salinity of water, causing alterations in the benthic populations, namely intertidal bivalves. Furthermore, salinity of a given environment will restrict the spatial distribution of the species, which is especially important when assessing the spread of an invasive species into a new environment. In order to understand how native (Venerupis decussata and Venerupis corrugata) and invasive (Venerupis philippinarum) clam species cope with salinity changes, physiological, biochemical and metabolomic patterns were investigated. The results obtained showed that V. decussata and V. philippinarum presented high mortality at low (0 and 7) but tolerate high (35 and 42) salinities. On the other hand, V. corrugata presented high mortality rates both at low (0 and 7) and high salinities (35 and 42). The quantification of Na and K content revealed that, along the salinity gradient, V. decussata was the species with higher ability to maintain the ionic homeostasis. The biochemical parameters also showed that V. decussata was the clam that best cope with salinity changes and V. corrugata was the most sensitive. Furthermore, the results obtained showed that clams under salinity stressful conditions can alter their biochemical mechanisms, such as increasing their antioxidant defences, to cope with the higher oxidative stress resulting from hypo and hypersaline conditions. Among the physiological and biochemical parameters analysed (glycogen, glucose and protein content; lipid peroxidation (LPO) levels, antioxidant enzymes activity; total, reduced and oxidized glutathione), superoxide dismutase (SOD), LPO and glutathione S-transferase (GST) showed to be useful biomarkers to assess salinity impacts in clams. The effects of salinity changes in the metabolic profile of the three species were also studied using 1H Nuclear Magnetic Resonance (NMR) spectroscopy of clam extracts. Multivariate analysis of the NMR spectra enabled metabolite changes to be observed in relation to clams exposure to different salinity concentrations. When exposed to low salinities, energy reserves of clams may be exhausted, increasing the osmotic imbalance, affecting the metabolic performance and increasing the oxidative stress. V. corrugata showed to be the most sensitive clam to salinity changes. The optimal salinity for V. decussata and V. philippinarum was between 21 and 28 and for V. corrugata was salinity 21. This study showed that changes in salinity have different impacts in native and invasive species
As respostas dos organismos aquáticos a alterações naturais, nomeadamente, alterações de salinidade, têm recebido pouca atenção, inversamente à preocupação que tem vindo a crescer em relação aos impactos da contaminação em populações marinhas bentónicas. De facto, a salinidade é um dos factores ambientais dominantes que mais afetam os bivalves marinhos, o que limita a sua distribuição espacial no ecossistema. As marés combinadas com entradas de água doce, de rios ou períodos de chuva longos e estações secas extremas, podem alterar drasticamente a salinidade da água, provocando alterações nas populações de bivalves bentónicos, nomeadamente intertidais. Além disso, a salinidade de um determinado ambiente irá restringir a distribuição espacial das espécies, o que é especialmente importante quando se avalia a propagação de uma espécie invasora num ambiente novo. A fim de entender como espécies nativas (Venerupis decussata e Venerupis corrugata) e invasoras (Venerupis phiippinarum) de molluscos lidam com as mudanças de salinidade, foram investigados parâmetros fisiológicos, bioquímicos e metablómicos. Os resultados obtidos mostraram que V. decussata e V. philippinarum apresentaram elevada mortalidade em salinidades baixas (0 e 7), mas toleram as salinidades mais altas (35 e 42). Por outro lado, V. corrugata apresentou elevadas taxas de mortalidade tanto em salinidades baixas (0 e 7) como em salinidades altas (35 e 42). A quantificação do teor de Na e K, revelou que ao longo do gradiente de salinidade, a V. decussata foi a espécie com maior capacidade de manter a homeostasia iónica. Os parâmetros bioquímicos também mostraram que V. decussata foi a espécie que melhor lidou com as mudanças de salinidade enquanto a V. corrugata foi a mais sensível. Além disso, os resultados obtidos mostraram que as ameijoas, sob condições adversas de salinidade, podem alterar os seus mecanismos bioquímicos, nomeadamente aumentando as suas defesas antioxidantes, para lidar com um maior stress oxidativo resultante das condições de hipo e hipersalinidade. Entre os parâmetros fisiológicos e bioquímicos analisados (glicogénio, glucose, proteinas, níveis de peroxidação lípidica (LPO), atividade de enzimas antioxidantes; glutationa total, reduzida e oxidada), LPO, superoxide dismutase (SOD) e glutathiona S-transferase (GST) mostraram ser biomarcadores úteis para avaliar os impactos de salinidade em bivalves. Os efeitos das alterações de salinidade no perfil metabólico das três espécies foram também estudados através de Ressonância Magnética Nuclear de 1H (RMN). A análise multivariada dos espectros de RMN permitiu a observação de alterações em relação à exposição de ameijoas a diferentes concentrações de salinidade. Quando expostos a baixas salinidades, as reservas energéticas destes organismos podem ser esgotadas, aumentando o desequilíbrio osmótico, afetando o desempenho metabólico e aumentando o stress oxidativo. V. corrugata mostrou ser a amêijoa mais sensível a mudanças de salinidade. O intervalo de salinidades entre 21 e 28 foi o ideal para V. decussata e V. philippinarum e a salinidade 21 foi a ideal para V. corrugata. Este estudo mostrou que as mudanças de salinidade têm impactos diferentes em espécies nativas e invasoras.
30
Leksungnoen, Nisa. "The Relationship Between Salinity and Drought Tolerance In Turfgrasses and Woody Species." DigitalCommons@USU, 2012. https://digitalcommons.usu.edu/etd/1196.
Full textAbstract:
Both salinity and drought stresses induce osmotic stress. Thus, cross-tolerance responses and mechanisms may occur in plants. The overall objectives of this study were to determine morphological and physiological responses and mechanisms of turfgrasses and woody species under salinity and drought stress conditions, and determine the relationship between drought and salinity tolerance ability in those species. Five turfgrass entries, ‘Gazelle’ and ‘Matador’ tall fescue (TF), ‘Midnight’ Kentucky bluegrass (KBG), PI368233 (Tolerant KBG), and PI372742 (Susceptible KBG), and three woody species, bigtooth maple (xeric-non saline), bigleaf maple (mesicnon saline) and Eucalyptus (mesic-saline) were compared. For the drought study, water was withheld in Chapter 2 while the dry down treatment was based on daily evapotranspiration (ET) in Chapters 5 and 6. For the salinity study, NaCl and CaCl2 in turfgrasses at electrical conductivity (EC) of 1, 6, 12, 18, and 30 dS m-1 (Chapter 3) and woody species at EC of 1, 3, 6, 9, and 12 dS m-1 (Chapter 4). Susceptible KBG was sensitive to s
31
Roden, John Warren III. "Determining the Physiological and Behavioral Methods of Salinity Tolerance in Corbicula fluminea." Digital Commons @ East Tennessee State University, 2018. https://dc.etsu.edu/asrf/2018/schedule/87.
Full textAbstract:
While a significant degree of salinity tolerance has been observed in the bivalve mollusk species Corbicula fluminea, the physiological and behavioral responses to changes in salinity by these organisms are not completely understood. It was hypothesized that Corbicula would initially avoid any salinity stress behaviorally through valve closure, but would eventually have to open to dispel anaerobic waste products and deal with the salinity. To explore this, Corbicula were collected and put through a series of experiments at salinity exposures of 0, 2.5, and 5.0ppt, with tissue water content and hemolymph osmolality being measured. After an initial 96-hour exposure period, it was observed that the tissue water content ratio of clams in 2.5ppt and 5.0ppt water dropped below that of the control groups in 0ppt. After a 24-hour time course experiment, it was observed that this change in tissue water largely occurred within the first eight hours of exposure for the 2.5ppt and 5.0ppt groups. It was also noted that the hemolymph osmolality of both the 2.5ppt and 5.0ppt groups rose to match the osmolality of the water in roughly the same time span. The osmolality of the control group did not match the osmolality of the 0ppt water, but was held at a constant level above it. In a later experiment measuring the same variables for clams in 10.0ppt, it was found that the tissue water and osmolality did not begin to change significantly until after 12 hours. The findings suggest that Corbicula osmoregulate at salinities lower than 2.5ppt, but osmoconform in salinities above that threshold. Furthermore, it seems that the clams are able and willing to tolerate conformation at 2.5ppt and 5.0ppt, but that they are reluctant to conform in 10.0ppt, behaviorally avoiding exposure for as long as possible.
32
Hoang, Thi My Linh. "Engineering salinity tolerance in rice by exogenous expression of cell death regulators." Thesis, Queensland University of Technology, 2014. https://eprints.qut.edu.au/72793/1/Thi%20My%20Linh_Hoang_Thesis.pdf.
Full textAbstract:
Rice, an important crop that feeds more than half of the world's population is very sensitive to salinity stress – a growing problem affecting crop production globally. This PhD study addressed this problem by manipulating the programmed cell death pathways in rice resulting in significant enhancement of salinity stress tolerance. The impact of this work is that farmers would be in a position to grow rice containing such a trait in environments where salinisation of the soil exists, thereby addressing food security needs.
33
Kemal-Ur-Rahim, K. "The effects of salinity on photosynthesis and other physiological processes in spring wheat varieties." Thesis, Bangor University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.380795.
Full text
34
Diédhiou, Calliste Jérémie. "Mechanisms of salt tolerance sodium, chloride and potassium homeostasis in two rice lines with different tolerance to salinity stress /." [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=979864097.
Full text
35
Denny, Geoffrey Carlile. "Evaluation of selected provenances of taxodium distichum for drought, alkalinity and salinity tolerance." [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-1327.
Full text
36
Al-Alhagdow, Moftah Moh. "Interactions between sodium and potassium in micropropagated potato cultivars differing in salinity tolerance." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape10/PQDD_0002/MQ44113.pdf.
Full text
37
Al-Hagdow, Moftah Moh. "Interactions between sodium and potassium in micropropagated potato cultivars differing in salinity tolerance." Thesis, McGill University, 1998. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=20554.
Full textAbstract:
The response of in vitro-grown Solanum tuberosum L., cvs. Russet Burbank (RB) (salt-sensitive) and Sierra (S) (salt-tolerant) potatoes was investigated when [NaCl] was increased from 0 to 80 mM in the presence of 6, 20, and 30 mM [K] in a Murashige and Skoog (MS) basal medium. The tested growth parameters, Mg and Ca content, and K+/Na + ratios in the laminae and the roots were negatively affected as [NaCl] increased. The salt stress was relatively severe on growth of RB plants whereas the salt-tolerant (S) variety was affected to a lesser extent. There were indications that Na in the plant may promote Na translocation. In both cultivars, 22Na was not distributed equally in all plant parts; the lower lamina accumulated the highest amount (216 and 183 DPM mg -1 FW) followed by stem (197 and 182), petioles (187 and 168), and the upper lamina (149 and 121) for RB and S, respectively.The salt resistance of S is associated not only with a superior capacity to accumulate high Na+ in the roots for osmotic adjustment, but also with resistance to Na movement to the shoot.
The effect of [K] on plant growth showed two main characteristics. In non-saline media, increasing [K] enhanced growth of S, while RB showed optimum growth when the normal (20 mM) level was present in the MS medium. In saline media, elevating [K] alleviated the growth reduction of RB at low salinity, and S at both low and high salinity. This ameliorative effect of K may be attributed to the suppression of both Na+ uptake, and Na + translocation in the plant.
38
Ali, Ghulam Muhammad. "Genetics and physiological basis of salinity tolerance in pearl millet (Pennisetum americanum L.)." Thesis, University of Liverpool, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367186.
Full text
39
Pace, Leonard. "Habitat Utilization and Salinity Tolerance of the Sandbar Shark, Carcharhinus plumbeus, in Virginia." W&M ScholarWorks, 2006. https://scholarworks.wm.edu/etd/1539617845.
Full text
40
Jattan, Sarabjit Singh. "Studies on growth and salinity tolerance in Acacia nilotica Dalbergia sissoo and Prosopis juliflora." Thesis, University of Oxford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315722.
Full text
41
Collins, R. P. "The role of calcium and potassium in salinity tolerance in Brassica rapa L. cv. RCBr seed." Thesis, Coventry University, 2012. http://curve.coventry.ac.uk/open/items/e0d653ff-7d6b-4827-9467-dc8bcb6ff621/1.
Full textAbstract:
The possibility of manipulating calcium (Ca2+) and potassium (K+) levels in seeds of Brassica rapa by altering parent plant nutrition and investigating the potential for increased salinity tolerance during germination, given that considerable amounts of literature imply that greater amounts of available exogenous Ca2+ and K+ can ameliorate the effects of salinity on both whole plant growth and germination, was evaluated. The investigation consisted of four growth trials. Two preliminary growth trials suggested that seed ion manipulation was possible without affecting the overall growth and vigour of the plant. After developing suitable high and low Ca2+ and K+ nutrient solutions for growth, a trial was carried out in a growth room and greenhouse, with various substrates and the seed of a certain size category was collected for subsequent ion and salinity tolerance analysis. Seed Ca2+ and K+ was significantly affected by growth substrate and nutrient solution and data showed that a significant negative regression relationship existed between seed Ca2+, K+ and Ca2+ + K+ levels and salinity tolerance. Further experimentation using hydroponic culture attempted to remove any possible effects of substrate and also to compare size categories of seed with a view to elucidating localisation of Ca2+ and K+. Seed Ca2+ was found to be significantly altered by nutrient solution in the two different sizes tested and higher Ca2+ nutrient solution was found to increase salinity tolerance in daughter seed. One significant negative regression correlation between salinity tolerance and seed K+ concentration existed in smaller seed, but disregarding seed size in a regression analysis of seed ion content and salinity tolerance, a significant negative relationship existed between seed Ca2+, K+ and Ca2++ K+. The results, especially in terms of Ca2+ nutrition, contradict much previous research that suggests increased salinity tolerance at germination can arise with the increased presence of Ca2+ and/or K+. Salinity tolerance was greater in seeds of larger size across all nutritional treatments and the smaller size range exhibited increased Ca2+ and K+ per μg seed. Ca2+ concentration in smaller seeds with greater surface area:volume ratios provided a clue to the potential localisation of Ca2+. Cross sectional staining showed that a greater proportion of seed Ca2+ may reside in the coat. This was confirmed by analysis which showed an approximate 50% split of total extractable seed Ca2+, regardless of size, between coat and embryo within a seed; the majority of which, per μg, resides in the coat. Further work looked at the relative solubility of the Ca2+ and K+ in these tissues and whole seed to look at the potential bioavailability of Ca2+ during germination from various parts of the seed. Most water soluble Ca2+ exists in the embryo and most insoluble Ca2+ exists in the coat, but coat Ca2+ was found to be ionically exchangeable and therefore bioavailable. K+ appeared mostly water soluble in embryo and coat. In line with previous whole plant research in this species, most Ca2+ is readily water soluble or ionically exchangeable in form and the possible negative effects of how increasing bioavailable Ca2+ may reduce salinity tolerance was discussed.
42
Robinson, Michael Frederick. "Sodium-induced stomatal closure in the maritime halophyte Aster tripolium (L.)." Thesis, Lancaster University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.337555.
Full text
43
Fraser, Duncan. "The potential of kikuyu grasses [Cenchrus clandestinus] for turf and pasture production under environmental stress." Thesis, The University of Sydney, 2019. https://hdl.handle.net/2123/21968.
Full textAbstract:
Kikuyu [Cenchrus clandestinus (Hochst. ex Chiov) Morrone] is an important pasture and turf species in Australia. However, little is known of the extent of adaptation of this species to environmental stresses. Naturalized populations and commercially released genotypes were compared in managed greenhouse and field experiments to establish the breadth of responses to salinity and drought stress. The physiological responses of materials to both salinity and drought stresses were determined using the normalized difference vegetative index (NDVI). Macro and micronutrients were assessed on vegetative matter harvested from each treatment at different stages of development using an inductively coupled plasma mass spectrometer. Amino acid variation was assessed at the same time using a liquid chromatograph mass spectrometer. Genotypes were subsequently ranked for salinity tolerance and significant variation in response was observed. Genotypes varied in nutrient levels under salinity stress with more tolerant genotypes showing lower rates of Na accumulation. Physiological adaptations among tolerant materials included exclusion and compartmentalization of Na. Amino acid concentrations varied with increasing salinity stress. However, salinity tolerance per say could not be ascribed to changes in any specific amino acid. Differences among genotypes for response to drought were observed in the field based on NDVI assessment. A relationship between salinity tolerance and WUE was suggested by the superior performance of some genotypes under both stresses. This is likely contributed by the same mechanisms as a significant genotype x stress treatment interaction was observed for both salinity and drought. However, it is unlikely that superior performance under stress is a consequence of genotype potential in the absence of stress.
44
Good, Victoria. "Investigating the Behavioral Response of Lampsilis ovata to Various Salinity Conditions." Digital Commons @ East Tennessee State University, 2020. https://dc.etsu.edu/honors/523.
Full textAbstract:
The Pocket-book mussel, Lampsilis ovata, is a native freshwater bivalve species that is endemic to North America. The salinity tolerance of this species is of interest because anthropogenic salinization events and climate change factors threaten their natural freshwater habitats. Furthermore, the invasive freshwater bivalve species Corbicula fluminea has been shown to display significant salinity tolerance, which may lead to negative competitive interactions with native freshwater bivalve species if the salinization of freshwater habitats exceeds thresholds beyond which native species can effectively cope. It was hypothesized that L. ovata would be sensitive to salinity conditions above 1 g/L and respond by closing their valves. To investigate this, juvenile pocket-book mussels were subjected to three experiments which measured tissue-water content, hemolymph osmolality, and oxygen consumption after salinity exposure to 0, 2.5, 5, and 10 g/L. The 96-hour exposure study showed that the 2.5 g/L and 5 g/L treatment groups had significantly lower average percent tissue-water content than the control group. The average percent tissue-water content for mussels exposed to 2.5 g/L and 5 g/L dropped 2.4% and 2.2%, respectively. In the 24-hour time-course study, it was observed that changes in the average percent tissue-water content for all treatment groups primarily occurred after four hours of exposure. In the same study, the osmolality of the control group maintained an average of 31.2 mOsm/kg over the 24-hour period, despite the osmolality of the treatment water being 2 mOsm/kg. The hemolymph osmolality concentration of mussels exposed to the 2.5 g/L and 5 g/L treatments increased to osmotically conform to their treatment waters. After 24 hours, the hemolymph osmolality of the 2.5 g/L and 5 g/L treatment groups was 79 mOsm/kg and 163 mOsm/kg, respectively. Contrastingly, the osmolality of mussels exposed to the 10 g/L treatment maintained an average hemolymph osmolality of approximately 132 mOsm/kg, while the osmolality of the treatment water was 320 mOsm/kg. Lastly, the oxygen-consumption study showed that mussels exposed to the 5 g/L treatment consumed a significantly lower amount of dissolved oxygen than that of the control and the 2.5 g/L treatment by an average of 1.6 mg O2/mg/h. The control group consumed an average of 4.66 mg O2/mg/h, while the 2.5 g/L treatment group consumed the highest amount of dissolved oxygen with an average of 5.05 mg O2/mg/h. The data collected from these studies suggest that juvenile L. ovata might not be able to tolerate salinities greater than 2.5 g/L for an extended amount of time. Mussels exposed to the 5 g/L treatment and the 10 g/L treatment demonstrated varying degrees of behavioral avoidance and much higher morbidity rates. In contrast, the 2.5 g/L treatment group showed minimal behavioral avoidance and an elevated oxygen consumption rate. When compared to similar studies performed on C. fluminea, these results support the hypothesis that L. ovata is more sensitive to saline conditions than the invasive species and could be replaced by the invasive species if habitat conditions exceeded 2.5 g/L salinity.
45
Zhang, Yanling. "Development of in vitro bioassays for determination of salinity tolerance in potato (Solanum spp.)." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape10/PQDD_0017/NQ44645.pdf.
Full text
46
Zhang, Yanling 1955. "Development of in vitro bioassays for determination of salinity tolerance in potato (Solanum spp.)." Thesis, McGill University, 1998. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=35659.
Full textAbstract:
Salinity problems seriously affect agricultural production by reducing crop yield and arable land. The evaluation of potato genotypes (Solanum spp.) for their salinity (NaCl) tolerance in conventional field trials is time consuming and labour intensive. The results are often confounded by many field and environmental variations. In vitro bioassays can overcome some of these difficulties by providing faster, more convenient and dependable methods for screening and selection of salt tolerant potato genotypes. The objective of this research was to develop in vitro bioassay methods for screening and selection of salt tolerant potato. Under in vitro NaCl stress conditions, seed germination, early seedling growth, and single-node cutting bioassays were used to evaluate salinity tolerance. The selected genotypes were further tested with three in vitro bioassays (single-node cuttings, root tip segments, and microtuberization). The rankings of potato cultivar salinity tolerance were similar in these bioassays. The single-node cutting bioassay was recommended because it was simpler to perform than the root tip segment and microtuberization bioassays and did not exclude certain genotypes as did the microtuberization bioassay. The in vitro bioassay rankings were compared with yield ranking in field lysimeters. In both the in vitro and in vivo saline stress experiments, cvs. Kennebec and Russet Burbank were more salt tolerant than Norland. The tubers and microtubers harvested from previous experiments were tested in the greenhouse to investigate salinity carry-over effect for seed tuber production. There was no apparent residual carry-over effect found. Microtuber yield increase in the presence of low NaCl concentration was induced primarily by specific ion (Na+), and not osmotic effects. This research clearly indicated that in vitro bioassays are relatively simple, rapid, convenient, repeatable, and agree with the field lysimeter results. They can be used to substitute for f
47
Alhammadi, Mohamed Salman. "Salt Tolerance and Current Status of the Date Palms in the United Arab Emirates." Diss., The University of Arizona, 2006. http://hdl.handle.net/10150/195448.
Full textAbstract:
This study aimed to address the current status of the United Arab Emirates date palms. The first chapter focused on the development of the date palm sector in the UAE. A huge increase in the date palm number was achieved in the past few decades. In the same time, there are critical issues facing this development, such as water demand, salinity, and Red Palm Weevil. The second chapter is a greenhouse experiment to test the growth of twelve date palm seeds at four NaCl levels, control, 3000, 6000, and 12000 ppm. Optimal growth found at control and 3000 ppm of NaCl. Relative growth rate (RGR), biomass, and NL decreased significantly by increasing salinity; however, no significant differences were observed in the average SGR for any cultivars. Increased NaCl leads to significant decreases in K+, Mg2+, and Ca2+ contents of plants. Na:K ratios were lower in shoots than in roots. Lulu, Fard, Khnaizi, Nabtat Safi, and Razez cultivars showed higher RGR and biomasses whereas Khnaizi, Mesally, and Safri had higher Na:K ratios than other cultivars in the control indicating higher Na+ discriminations from plant parts. The third chapter studied the vegetation change in the eastern region of the UAE. Due to shortage of fresh water resources, the vegetation of the eastern region of the UAE has experienced a series of declines resulting from salinization of groundwater. To assess these changes, field measurements combined with Thematic Mapper (TM) and Enhanced Thematic Mapper Plus (ETM+) based Soil Adjusted Vegetation Index (SAVI) were analyzed. Images from two dates, 1987 and 2000 were acquired to enable the computation of the greenness anomalies for three sites in the eastern region, Fujairah, Kalba, and Hatta. The results show an overall increase in the agricultural area, associated with a severe decrease in vegetation greenness and health conditions, particularly in the Kalba study area. The SAVI values decreased with increased soil salinity, permitting the identification of salt-affected areas. Potential areas of further research range from studying the effects of tree spacing and understory crops as immediate and potential solutions to maintain productivity and mitigate the salinity problem.
48
Jafari, Mostafa. "The potential for improvement of salinity and drought tolerance in some semi-arid forage grasses." Thesis, University of Liverpool, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.316911.
Full text
49
Fitwi, Biniam Samuel. "Determination of salinity tolerance limits of tilapia, Oreochromis mossambicus, for use in tuna line fishery." Thesis, Stellenbosch : Stellenbosch University, 2003. http://hdl.handle.net/10019.1/53355.
Full textAbstract:
Assignment (MPhil)--Stellenbosch University, 2003.ENGLISH ABSTRACT: Many species of tilapia such as Oreochromis mossambicus are euryhaline, able to adapt to different salinity waters. Their ability to withstand high salinity levels has given rise to the possibility of using tilapia as baitfish for tuna line fishery. The purpose of the study was to determine the survival rate of tilapia O. mossambicus during direct transfer from freshwater to the salinity levels of 0, 15, 20, 22.5, 25, 27.5, 30, 32.5, and 35 ppt. The data was analysed through means of univariate ANOVAand regression analysis. O. mossambicus showed no mortality to all salinity regimes up to 25 ppt. Mortality was observed at 27.5 ppt, with 100% mortality at 35 ppt. LC 50 and LC 90 were found to be 30.5 and 34.2 ppt, respectively. The results indicate that tilapia (0. mossambicus) will survive a direct transfer to salinities up to 25 ppt. acclimation will be required in the event of transfer to salinity levels above 25 ppt, in order to prevent significant levels of mortalities.
AFRIKAANSE OPSOMMING: Meeste van die tilapia spesies soos Oreochremis mossambicus het die vermoë om by water van verskillende soutgehaltes aantepas. Dit is hierdie vermoë om hoë sout vlakke te weerstaan wat die moontlikheid vir gebruik as lewende aas in die tuna langlyn visvangbedryf moontlik maak. Die doel van hierdie studie was om die oorlewingsvlak van tilapia, O. mossambicus te bepaal by die oorplasing van varswater direk na soutwater by vlakke van 0, 15, 20, 22.5, 25, 27.5, 30, 32.5, en 35 dele per duisend. Die data is verwerk deur gebruik te maak van eenvariant ANOVAen regressie analises. O. mossambicus het geen mortaliteite tot gevolg gehad by al die oorplasings van vlakke tot en met 25 dele per duisend sout nie. Mortaliteite is wel gevind vanaf 27.5 dele per duisend, met 100 % mortaliteite by 35 dele per duisend. LC 50 en LC90 was gewees 30.5 en 34.2 dele per duisend onderskeidelik. Die resultate toon aan dat tilapia (0. mossambicus) sal oorleef by direkte oorplasing na soutwater by vlakke van tot en met 25 dele per duisend. Tilapia wat na hoër vlakke as 25 dele per duisend oorgeplaas wil word, sal eers geleidelik moet akklimatiseer om mortaliteite te beperk.
50
Roden, John. "Determining the physiological and behavioral aspects of salinity tolerance in the Asian clam, Corbicula fluminea." Digital Commons @ East Tennessee State University, 2018. https://dc.etsu.edu/honors/443.
Full textAbstract:
The Asian clam, Corbicula fluminea, is an invasive bivalve species that now occurs through most of the lower 48 United States. While a significant degree of salinity tolerance has been observed in C. fluminea, owing to its estuarine lineage, the physiological and behavioral responses to changes in salinity by these organisms are not completely understood. It was hypothesized that Corbicula would initially avoid elevated salinity levels (>1 g/L) behaviorally through valve closure, but would eventually have to open to dispel anaerobic waste products and deal with the salinity. To explore this, Corbicula were collected and put through a series of experiments at salinity exposures of 0, 2.5, and 5.0 g/L, with tissue water content and hemolymph osmolality being measured. After an initial 96-hour exposure, it was observed that the percent tissue water content of clams in 2.5 g/L and 5.0 g/L water dropped 3.29% and 4.18%, respectively, below that of the control groups in 0 g/L. After a 24-hour time-course experiment, this change in tissue water was found to largely occur within the first eight hours of exposure for the 2.5 g/L and 5.0 g/L groups. It was also noted that the hemolymph osmolality of both the 2.5 g/L and 5.0 g/L groups rose to approximately 78 mOsm/kg and 148 mOsm/kg, respectively, matching the osmolality of their exposure water in roughly the same time span and indicating that little behavioral avoidance of the elevated salinity was occurring. The osmolality of the control group did not match the osmolality of the 0 g/L water at 0.5 mOsm/kg, but was held at a constant level around 50 mOsm/kg. In a later experiment measuring the same variables for clams in 10.0 g/L, it was found that the tissue water and osmolality did not begin to change significantly until after 12 hours, indicating behavioral avoidance at this salinity level. A context study was also conducted comparing oxygen consumption and percent tissue water between various salinities in a light and dark exposure to determine if ambient light influenced siphoning of the clams and exposure to the salt. In this experiment, it was observed that clams held in salinities of 5.0 g/L for 24 hours consumed roughly 1.90 mg O2/L/g/h, whereas clams held in the control only consumed roughly 0.73 mg O2/L/g/h. These findings suggest that Corbicula osmoregulate in freshwater but osmoconform at salinities of 2.5 g/L and 5.0 g/L. The data from the context study also suggests that this conformation comes at a significant metabolic cost. Furthermore, and in contrast to the results of some previous studies, a significant level of behavioral avoidance of elevated salinity does not appear to commence until the clams are at a salinity above 5 g/L.