Highly crystalline and thermally stable pure multi-walled Ni 3 Si 2 O 5 (OH) 4 nanotubes with a layered structure have been synthesized in water at a relatively low temperature of 200-210 °C using a facile and simple method. The nickel ions between the layers could be reduced in situ to form size-tunable Ni nanocrystals, which endowed these nanotubes with tunable magnetic properties. Additionally, when used as the anode material in a lithium ion battery, the layered structure of the Ni 3 Si 2 O 5 (OH) 4 nanotubes provided favorable transport kinetics for lithium ions and the discharge capacity reached 226.7 mA·h·g -1 after 21 cycles at a rate of 20 mA·g -1 . Furthermore, after the nanotubes were calcined (600 °C , 4 h) or reduced (180 °C , 10 h), the corresponding discharge capacities increased to 277.2 mA·h·g -1 and 308.5 mA·h·g -1 , respectively.

The controllable synthesis of materials with the desired crystal structure and dimensionality is of great significance in material science. In this work we report the successful synthesis of amorphous and crystalline zinc silicates with different dimensionalities and well-defined shapes, including hollow spheres, nanowires and membranes. The structure-related absorption properties have been studied. A detailed study of their ability to remove Pb(Ⅱ), Cd(Ⅱ), Cr(Ⅲ), and Fe(Ⅲ) ions has been performed. The amorphous zero-dimensional (0-D) hollow spheres show the best removal ability for all the metal ions investigated. In particular, their absorption capacity for Pb(Ⅱ) ions is 129 mg/g, which is double the value reported for magnesium silicate hollow spheres. However, the removal abilities of crystalline one-dimensional (1-D) nanowires and two-dimensional (2-D) membranes are found to be dependent on the charge of the target metal ion. In general, nanowires show better removal capacity for trivalent ions, especially Fe(Ⅲ), while 2-D membranes exhibit better removal capacity for divalent ions.

Key messageA salicylic acid-inducible WRKY gene,PtrWRKY73,fromPopulus trichocarpa, was isolated and characterized. Overexpression ofPtrWRKY73inArabidopsis thalianaincreased resistance to biotrophic pathogens but reduced resistance against necrotrophic pathogens.AbstractWRKY transcription factors are commonly involved in plant defense responses. However, limited information is available about the roles of the WRKY genes in poplar defense. In this study, we isolated a salicylic acid (SA)-inducible WRKY gene, PtrWRKY73, from Populus trichocarpa, belonging to group I family and containing two WRKY domains, a D domain and an SP cluster. PtrWRKY73 was expressed predominantly in roots, old leaves, sprouts and stems, especially in phloem and its expression was induced in response to treatment with exogenous SA. PtrWRKY73 was localized to the nucleus of plant cells and exhibited transcriptional activation. Overexpression of PtrWRKY73 in Arabidopsis thaliana resulted in increased resistance to a virulent strain of the bacterial pathogen Pseudomonas syringae (PstDC3000), but more sensitivity to the necrotrophic fungal pathogen Botrytis cinerea. The SA-mediated defense-associated genes, such as PR1, PR2 and PAD4, were markedly up-regulated in transgenic plants overexpressing PtrWRKY73. Arabidopsis non-expressor of PR1 (NPR1) was not affected, whereas a defense-related gene PAL4 had reduced in PtrWRKY73 overexpressor plants. Together, these results indicated that PtrWRKY73 plays a positive role in plant resistance to biotrophic pathogens but a negative effect on resistance against necrotrophic pathogens.Electronic supplementary materialThe online version of this article (doi:10.1007/s00299-015-1745-5) contains supplementary material, which is available to authorized users.

No abstract

No abstract