Arbuscular mycorrhizas (AM) are the plant root-fungus interactions that are most widespread mycorrhiza in nature. As classically defined, there are two major AM morphologies named after the plant genera in which they were first described: Arum- (intercellular hyphae with arbuscules mainly in inner root cortex), Paris- (extensive hyphal coils in outer root cortex), as well as intermediate morphotypes. In this study, dandelions and chives harvested in Saskatoon (SK, Canada) were examined for AM colonization and morphological types. A Multiple Quantitation Method (MQM) was used for assessing fungal colonization intensity using magnified epifluorescence images of lactofuchsin stained roots, plus details analyzed by high-resolution confocal fluorescence imaging. The results showed that host plants harbored diverse endorhizal fungi, including arbuscular mycorrhizal fungi (AMF), septate endophytes (SE) and fine endophytes (FE), with varying abundances. The soil properties were assessed with respect to P status, organic matter and pH, but there was no correlation with the fungal abundance in this study. Both dandelion and chive roots had Arum- and Paris-type AM. In order to assess the applicability of a current model, I studied quantitative relationship between the cell packing pattern and AM morphotype. Cross sections of host roots were analyzed with Image J software to calculate the proportion of air spaces. The abundance of arbuscules (Arum-type) and hyphal coils (Paris-type) were significantly different in chive and dandelion roots. However, there was no difference in the proportion of air spaces in the inner or outer cortex. Therefore, host root cell packing does not appear to influence AM morphotype at least in the samples in this study. AM fungal diversity was preliminarily investigated by nested PCR with group specific primers, showing multiple PCR bands within root samples, and indicating the potential complexity of AMF groups. Further work to sequence the PCR products is needed to elucidate the AMF groups present.

Arbuscular mycorrhizas (AM) are the plant root-fungus interactions that are most widespread mycorrhiza in nature. As classically defined, there are two major AM morphologies named after the plant genera in which they were first described: Arum- (intercellular hyphae with arbuscules mainly in inner root cortex), Paris- (extensive hyphal coils in outer root cortex), as well as intermediate morphotypes. In this study, dandelions and chives harvested in Saskatoon (SK, Canada) were examined for AM colonization and morphological types. A Multiple Quantitation Method (MQM) was used for assessing fungal colonization intensity using magnified epifluorescence images of lactofuchsin stained roots, plus details analyzed by high-resolution confocal fluorescence imaging. The results showed that host plants harbored diverse endorhizal fungi, including arbuscular mycorrhizal fungi (AMF), septate endophytes (SE) and fine endophytes (FE), with varying abundances. The soil properties were assessed with respect to P status, organic matter and pH, but there was no correlation with the fungal abundance in this study. Both dandelion and chive roots had Arum- and Paris-type AM. In order to assess the applicability of a current model, I studied quantitative relationship between the cell packing pattern and AM morphotype. Cross sections of host roots were analyzed with Image J software to calculate the proportion of air spaces. The abundance of arbuscules (Arum-type) and hyphal coils (Paris-type) were significantly different in chive and dandelion roots. However, there was no difference in the proportion of air spaces in the inner or outer cortex. Therefore, host root cell packing does not appear to influence AM morphotype at least in the samples in this study. AM fungal diversity was preliminarily investigated by nested PCR with group specific primers, showing multiple PCR bands within root samples, and indicating the potential complexity of AMF groups. Further work to sequence the PCR products is needed to elucidate the AMF groups present.

This research presents the results on an experimental investigation to identify the effect of polyphosphoric acid (PPA) on aging characteristics of an asphalt binder. Addition of PPA to asphalt binders is said to improve performance of flexible pavements. Asphalt binder PG 64-22 in modified and unmodified conditions was subjected to aging in the laboratory using a regular oven and also simulated short term aging using rolling thin film oven (RTFO) test. Aging experiments were conducted to analyze the extent of oxidation in terms of changes in molecular structure of the asphalt binder. These changes were appraised using Fourier transform infrared (FTIR) spectroscopy, dynamic shear rheometer (DSR), and epifluorescence microscopy tests. FTIR was used to determine the changes in major bands with addition of PPA. Stiffness and viscoelastic behaviors of asphalts were determined from the DSR test. The stiffness is measured by calculating the shear modulus, G* and the viscoelastic behavior is measured by calculating the phase angle, sin δ. Epifluorescence microscopy is a tool used to study properties of organic or inorganic substances. The morphological characteristics of PPA modified asphalt samples were observed through epifluorescence microscopy. Epifluorescence microscopy reveals the polymer phase distribution in the asphalt binders. Results of this investigation show PPA addition to asphalt binders improve G*/sin δ characteristics of asphalt binders. In addition, presence of PPA in polymer containing asphalt did not adversely affect aging of the binders.

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