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Helictotrichon sempervirens (blue oatgrass) is a perennial grass widely grown for ornamental use in Canada. Rusted blue oatgrass plants with diseased leaves covered with uredinia were collected from two locations at metropolitan Vancouver, British Columbia (BC), in summer 2022. The rust fungus was identified as Puccinia gibberosa (= P. coronata var. gibberosa) based on combined results of morphological characteristics and molecular analyses. The internal transcribed spacer two (ITS2) and partial large subunit ribosomal DNA were amplified and sequenced. The sequence obtained for the rust fungus showed 99.9% identity with the previously reported P. coronata var. gibberosa from USA. This is the first report of rust caused by P. gibberosa on blue oatgrass in Canada. Evidence from phylogenetic analyses supports the recognition of this rust at the species level. A revised description for P. gibberosa is provided, including synonyms, host range and distribution across the globe, and incorporating comprehensive molecular and morphological results for several North American and European specimens. In addition, a lectotype and an epitype are designated here for the rust species. [ABSTRACT FROM AUTHOR]

As an agroforestry resource willow species (Salix spp.) becoming increasingly important in the protection of riverbanks, recovery of floodable lands, soil bioremediation, biomass production, and wicker furniture manufacture, Babylon willow (Salix babylonica) is widely planted all over the world and is found throughout Iran as part of the rural landscape and is mostly planted for ornamental or bioremediation purposes. Rust fungi in the genus Melampsora usually cause disease on Salix species. Identification of Melampsora species is often complicated because there are few differences in spore morphology and little is publicly available in comparative sequence data. Willow trees in Iran have been reported to be infected by 15 Melampsora species; however, most of these records are based on morphological characterization. During surveillance activities carried out in June 2007, a rust species was detected on isolated Babylon willow trees in an area in Northern Iran. Both the rust fungus and the host plant were identified on the basis of morphological features and DNA sequencing. Based on a combination of morphology, large subunit (LSU) rDNA sequencing and phylogenetic analyses, our rust specimen was identified as Melampsora ferrinii, which is newly reported from Iran on Salix babylonica. Melampsora ferrinii was originally described from the Americas and this is the first time that this rust has been observed on its telial host, Babylon willow, in Asia. The documentation of the rust fungus was performed using both scanning electron microscopy (SEM) and light microscopy. Additionally, an identification key for Melampsora species reported on Salix spp. in Iran is included. [ABSTRACT FROM AUTHOR]

Amorphous titanium dioxide (TiO2) film coating by atomic layer deposition (ALD) is a promising strategy to extend the photoelectrode lifetime to meet the industrial standard for solar fuel generation. To realize this promise, the essential structure-property relationship that dictates the protection lifetime needs to be uncovered. In this work, we reveal that in addition to the imbedded crystalline phase, the presence of residual chlorine (Cl) ligands is detrimental to the silicon (Si) photoanode lifetime. We further demonstrate that post-ALD in-situ water treatment can effectively decouple the ALD reaction completeness from crystallization. The as-processed TiO2 film has a much lower residual Cl concentration and thus an improved film stoichiometry, while its uniform amorphous phase is well preserved. As a result, the protected Si photoanode exhibits a substantially improved lifetime to ~600 h at a photocurrent density of more than 30 mA/cm2. This study demonstrates a significant advancement toward sustainable hydrogen generation. Residual Cl ligands are found critical to the stability of amorphous TiO2 coatings by atomic layer deposition. Here, in-situ water treatment is developed to remove residual Cl, while preserve its uniform amorphous phase, which improves the lifetime of Si photoanode to 600 h for hydrogen production. [ABSTRACT FROM AUTHOR]

The evolution of medium range ordering (MRO) and crystallization behavior of amorphous TiO2 films grown by atomic layer deposition (ALD) were studied using in situ four-dimensional scanning transmission electron microscopy. The films remain fully amorphous when grown at 120 °C or below, but they start showing crystallization of anatase phases when grown at 140 °C or above. The degree of MRO increases as a function of temperature and maximizes at 140 °C when crystallization starts to occur, which suggests that crystallization prerequires the development of nanoscale MRO that serves as the site of nucleation. In situ annealing of amorphous TiO2 films grown at 80 °C shows enhancement of MRO but limited number of nucleation, which suggests that post-annealing develops only a small portion of MRO into crystal nuclei. The MRO regions that do not develop into crystals undergo structural relaxation instead, which provides insights into the critical size and degree of ordering and the stability of certain MRO types at different temperatures. In addition, crystallographic defects were observed within crystal phases, which likely negate corrosion resistance of the film. Our result highlights the importance of understanding and controlling MRO for optimizing ALD-grown amorphous films for next-generation functional devices and renewable energy applications. [ABSTRACT FROM AUTHOR]