In mehrjährigen Gefäß- und Feldversuchen wurde der Einfluß von selektierten arbuskulären Mykorrhizapilzen (Glomus ssp. VAM3, Glomus intraradices Isolat 49) und assoziativen Rhizosphärenbakterien (Pseudomonas fluorescens PsIA12, Agrobacterium rhizogenes A1A4, Rhizobium trifolii R39, Stenotrophomas maltophilia PsIB2 und PsI2) einzeln und kombiniert auf das Wachstum und den Zierwert von ein- und mehrjährigen Zierpflanzen für den urbanen Bereich untersucht. Auf urbanen streßbelasteten Standorten führten diese Rhizosphärenmikroorganismen ohne zusätzliche Mineraldüngung zur Förderung von Wachstum und Zierwert bei Zierpflanzen. Frühzeitige Inokulationen zur Aussaat bzw. Pflanzung verkürzten die Pflanzenanzucht und reduzierten Pflanzenausfälle. Die drei Pflanzenarten reagierten unterschiedlich. Die deutlichsten Effekte wurden bei Tagetes durch Einzelinokulationen erzielt. Es zeichneten sich sortenspezifische Reaktionen ab. Bei Miscanthus waren Kombinationen von Mikroorganismen wirksam und förderten das Wachstum über drei Jahre. Nicht eindeutig reproduzierbar waren die Wirkungen bei Gladiolen, der Zierwert wurde positiv beeinflußt. Alle Bakterienstämme produzierten in Reinkultur Auxine und z.T. Cytokinine. Zwischen Phytohormonbildung, Mykorrhizierung der Wurzeln, Wurzelbesiedlung durch die autochthone Mikroflora und Wurzelstimulierung zeichneten sich wiederholt positive Wechselwirkungen ab. Von Ackerstandorten isolierte Bakterien waren auch auf urbanen nährstoffarmen Standorten wirksam. Die Bakterien besiedelten die Rhizosphäre von Tagetes und Gladiolen während der Vegetationsperiode im Freiland. Nach einjähriger Trockenlagerung des Bodens besiedelten PsIA12 und PsIB2 erneut die Rhizosphäre der nichtinokulierten Tagetes. / In long-term pot and field trials the influence of selected arbuscular mycorrhizal fungi (Glomus ssp. VAM3, Glomus intraradices Isolat 49) and associative rhizosphere bacteria (Pseudomonas fluorescens PsIA12, Agrobacterium rhizogenes A1A4, Rhizobium trifolii R39, Stenotrophomas maltophilia PsIB2 and PsI2), single and in combination, on growth and ornamental value of annual and perennial ornamental plants under urban conditions was tested. These rhizosphere microorganisms did stimulate growth and ornamental value of ornamental plants without the additon of mineral fertilizers on urban stressed sites. An early inoculation during seeding or planting did shorten plant cultivation and reduced plant losses. The three plant species did respond differently. The most obvious effects were achieved by single inoculation on Tagetes. Variety specific reactions did occur. Combination of microorganisms was effective on Miscanthus and did stimulate growth over three years. The effects on Gladiolus were not repeatable but ornamental value was stimulated. All bacteria strains did produce Auxin and partially Cytokinin in pure culture. Between phytohormone production, root mycorrhization and root colonization by the autochthonous microflora positive interactions did occur. Bacteria isolated from agricultural sites were also effective on oligotrophic urban sites. The bacteria did establish in the rhizosphere of Tagetes and Gladiolus over the vegetation period on the field. After one year dry storage of the soil PsIA12 and PsIB2 did re-establish in the non-inoculated Tagetes rhizosphere.

Naphthenic acids (NAs) are toxic organic acid compounds released during the caustic hot-water extraction of crude oil from oil sands in north-eastern Alberta, Canada. NAs subsequently accumulate in the large volume of oil sands process water (OSPW) produced daily by oil sands operations. The complexity of dealing with a mixture of over 200 individual NA compounds, combined with their acute aquatic toxicity and large volume of production has made them an emerging pollutant of concern for western Canada. The following thesis outlines a variety of experiments designed to determine the potential to use wetland plants to enhance the dissipation of NAs from OSPW (phytoremediation). <p>Investigations were carried out with three native emergent macrophyte species cattail (<i>Typha latifolia</i>), common reed (<i>Phragmites australis </i>subsp. <i>americanus</i>), and hard-stem bulrush (<i>Scirpus acutus</i>) to see if they enhanced the dissipation of NAs from a hydroponic system. Dissipation of NAs (at 30 mg L-1 and 60 mg L-1) was investigated with both a commercially available NA mixture as well as with a NA mixture extracted from the OSPW. Dissipation of NAs was also investigated under the different ionized forms of NAs (ionized, pH = 7.8; and non-ionized, pH = 5.0) to better elucidate the mechanisms of NA uptake and toxicity in plants. Phytotoxicity of NAs was investigated in hydroponic experiments through fresh weight gain and evapotranspiration was monitored throughout the experiment by water uptake. Commercially available NA mixture was more phytotoxic than oil sands NAs mixture. As well, NAs were found to be more phytotoxic in their non-ionized form therefore indicating that they may be taken up through an ion-trap‟ mechanism. However despite this, no significant dissipation of total NAs was observed from planted hydroponic systems. Nevertheless there was a significant change in the distribution (percent abundance) of individual NA families of certain size. These changes were related to the one- and two-ring NA compounds (Z = -2 and Z = -4). Despite not detecting any dissipation of total NAs from the systems, plants were able to reduce the toxicity of a NA system over 30 days by 45% as determined by Daphnia magna acute toxicity bioassays; a 11% greater reduction than unplanted systems.<p> Studies were also conducted investigating the microbial community inhabiting cattail roots exposed to NAs. It was observed that the rhizosphere community changed with NA exposure, with a general increase in potentially pathogenic bacteria and a decrease in bacteria previously found to be beneficial to plant growth. The observed microbial community change could be an indirect effect of the Phytotoxicity experienced by aquatic macrophytes exposed to NAs. Synchrotron-sourced, fourier transform microspectroscopy analysis of root cross sections revealed that there were significant physiological changes to those roots exposed to NAs. These changes were identified as being cell death in the plant root epidermis as well as a change in the chemistry of parenchyma cells in the root pith. It is not known if these changes are a direct effect of NAs to the plant or due to changes of the associated rhizosphere community in the roots or some combination of both these factors.

Naphthenic acids (NAs) are toxic organic acid compounds released during the caustic hot-water extraction of crude oil from oil sands in north-eastern Alberta, Canada. NAs subsequently accumulate in the large volume of oil sands process water (OSPW) produced daily by oil sands operations. The complexity of dealing with a mixture of over 200 individual NA compounds, combined with their acute aquatic toxicity and large volume of production has made them an emerging pollutant of concern for western Canada. The following thesis outlines a variety of experiments designed to determine the potential to use wetland plants to enhance the dissipation of NAs from OSPW (phytoremediation). <p>Investigations were carried out with three native emergent macrophyte species cattail (<i>Typha latifolia</i>), common reed (<i>Phragmites australis </i>subsp. <i>americanus</i>), and hard-stem bulrush (<i>Scirpus acutus</i>) to see if they enhanced the dissipation of NAs from a hydroponic system. Dissipation of NAs (at 30 mg L-1 and 60 mg L-1) was investigated with both a commercially available NA mixture as well as with a NA mixture extracted from the OSPW. Dissipation of NAs was also investigated under the different ionized forms of NAs (ionized, pH = 7.8; and non-ionized, pH = 5.0) to better elucidate the mechanisms of NA uptake and toxicity in plants. Phytotoxicity of NAs was investigated in hydroponic experiments through fresh weight gain and evapotranspiration was monitored throughout the experiment by water uptake. Commercially available NA mixture was more phytotoxic than oil sands NAs mixture. As well, NAs were found to be more phytotoxic in their non-ionized form therefore indicating that they may be taken up through an ion-trap‟ mechanism. However despite this, no significant dissipation of total NAs was observed from planted hydroponic systems. Nevertheless there was a significant change in the distribution (percent abundance) of individual NA families of certain size. These changes were related to the one- and two-ring NA compounds (Z = -2 and Z = -4). Despite not detecting any dissipation of total NAs from the systems, plants were able to reduce the toxicity of a NA system over 30 days by 45% as determined by Daphnia magna acute toxicity bioassays; a 11% greater reduction than unplanted systems.<p> Studies were also conducted investigating the microbial community inhabiting cattail roots exposed to NAs. It was observed that the rhizosphere community changed with NA exposure, with a general increase in potentially pathogenic bacteria and a decrease in bacteria previously found to be beneficial to plant growth. The observed microbial community change could be an indirect effect of the Phytotoxicity experienced by aquatic macrophytes exposed to NAs. Synchrotron-sourced, fourier transform microspectroscopy analysis of root cross sections revealed that there were significant physiological changes to those roots exposed to NAs. These changes were identified as being cell death in the plant root epidermis as well as a change in the chemistry of parenchyma cells in the root pith. It is not known if these changes are a direct effect of NAs to the plant or due to changes of the associated rhizosphere community in the roots or some combination of both these factors.