Cathodoluminescence and tip-plasmon resonance of Bi2Te3 triangular nanostructures.

Bi2Te3, as a topological insulator, is able to support plasmonic emission in the visible spectral range. Thin Bi2Te3 flakes can be exfoliated directly from a Bi2Te3 crystal, and the shape of Bi2Te3 flakes can be further modified by focused ion beam milling. Therefore, we have designed a Bi2Te3 triangular antenna with distinct tip angles for the application of plasmonic resonance. The plasmonic emission of the Bi2Te3 triangular antenna is excited and investigated by cathodoluminescence in the scanning electron microscope. Enhanced tip plasmons have been observed from distinct tips with angles of 20º, 36º, 54º, 70º, and 90º, respectively. Due to the confinement of geometric boundaries for oscillating charges, the resonant peak position of tip plasmon with a smaller angle has a blue shift. Moreover, the dependence of plasmonic behavior on the excitation position has been discovered as well. This research provides a unique approach to fabricate Bi2Te3 nanostructures and manipulate the corresponding plasmonic properties.

Photosynthesis-related physiology and metabolomics responses of Polygonum lapathifolium in contrasting manganese environments.

Manganese (Mn) plays an essential role in plant growth; however, excessive Mn is toxic to plants. Polygonum lapathifolium Linn. was tested as a novel Mn-hyperaccumulating species in our previous study, but the underlying mechanisms of this hyperaccumulation are poorly understood. A hydroponic experiment with (8mmolL-1 ) and without additional Mn (CK) was established to explore the possible mechanisms through the effects on photosynthesis-related physiological characteristics and metabolomics. The results showed that additional Mn increased plant biomass, photosynthesis, and stomatal conductance related to increases in the effective photochemical quantum yield of photosystem II and relative electron transport rate (P <0.05). The results from liquid chromatography-mass spectrometry revealed 56 metabolites differentially accumulated between the plants composing these two groups. Metabolites were enriched in 20 metabolic pathways at three levels (environmental information processing, genetic information processing, and metabolism), of which five metabolic pathways were associated with significant or extremely significant changes (P <0.05). These five enriched pathways were ABC transporters (environmental information processing), aminoacyl-tRNA biosynthesis (genetic information processing), biosynthesis of amino acids , d -arginine and d -ornithine metabolism , and arginine biosynthesis (metabolism). Flavonoids may play a key role in Mn tolerance, as they accumulated more than 490-fold, and the relationship between flavonoids and Mn tolerance needs to be studied in the future.

[Application of biogas fermentation residue in Ziziphus jujuba cultivation].

With field experiment, this paper studied the effects of applying biogas fermentation residue (dregs and slurry) on jujube growth, its fruit quality, and soil fertility. The results showed that biogas fermentation residue could enhance the disease-resistance of jujube plant and its fruit, and improve fruit quality and soil fertility. Compared with applying chemical fertilizers (the control), biogas fermentation residue increased the contents of jujube fruit coarse fiber, vitamin C, amino acids, Fe and P by 27.69%, 24.85%, 19.81%, 10.89% and 5.26%, and of soil organic carbon, total nitrogen and mineral nitrogen by 42.65%, 37.61% and 35.26%, respectively. The soil pH was decreased from 8.75 to 8.21. Biogas fermentation residue could also increase the amount of soil microorganisms. The microbial biomass-C and biomass-N were 59.44% and 56.06% higher than the control, respectively. It was suggested that biogas fermentation residue application could bring better economic and environmental benefits for Z. jujuba cultivation, and also, provide a new approach for no-pollution production of jujube.