Comparative Transcriptome Analysis Revealing the Potential Mechanism of Low-Temperature Stress in Machilus microcarpa.

Machilus microcarpa is a rare national tree species in China and possesses important ornamental and ecological value. M. microcarpa can be planted in low-temperature areas, depending on whether its seedlings can withstand the harm. To face this problem, the annual seedlings of M. microcarpa were subjected to five temperature treatments, and eight physiological indicators were measured. Furthermore, comparative transcriptome analysis was performed between M. microcarpa leaves treated at 25°C and -2.8°C. A total of 9,385 differentially expressed genes (DEGs) were involved in low-temperature stress in M. microcarpa. An upregulated (cobA) and five downregulated (HEM, CHLM, CRD, CLH, and PORA) genes associated with the porphyrin and chlorophyll metabolism pathway may reduce chlorophyll synthesis under low-temperature stress. Upregulation of six DEGs (two GAPDHs, PFK, PGAM, PDC, and PK) involved in the glycolysis/gluconeogenesis pathway provided energy for M. microcarpa under adverse cold conditions. Thirteen upregulated and seven downregulated genes related to antioxidant enzymes were also observed under low-temperature stress. Candidate transcription factors (TFs) played key roles in signal transduction under low-temperature stress in M. microcarpa, and quantitative real-time PCR (qRT-PCR) analysis validated the RNA-seq data. The results provide valuable information for further studies on the cold response mechanisms for low-temperature stress in M. microcarpa.

Ni, Eu-Co doping effect on the photocatalytic activity and magnetic recyclability in multifunctional single-phase photocatalysts Bi5FeTi3O15.

Bi5-yEuyFe1-xNixTi3O15 (x = 0, 0.05, 0.10, 0.15, 0.20; y = 0, 0.1, 0.3, 0.5) nanosheet-based nanoflowers as magnetic recyclable visible-light photocatalysts toward Rhodamine B (RhB) degradation were successfully synthesized by a hydrothermal method. As started from Bi5FeTi3O15 (BFTO), Ni was firstly employed to substitute for Fe at B-site to improve the magnetism for magnetic recyclability. After Ni doping (Bi5Fe1-xNixTi3O15: BFNTO-x, x = 0, 0.05, 0.10, 0.15, 0.20), both the ferromagnetism and photocatalytic activity were obviously improved, where BFNTO-0.1 (Bi5Fe0.9Ni0.1Ti3O15) exhibited the maximum remnant and statured magnetization of 0.14 and 0.82 emu/g respectively. To further improve the magnetism and photocatalytic activity, Eu was chosen to substitute for Bi at A-site. Both ferromagnetism and photocatalytic properties of Bi5-yEuyFe0.9Ni0.1Ti3O15 (BEFNTO-y, y = 0, 0.1, 0.3, 0.5) were further improved by optimizing the doped europium content. The BEFNTO-0.1 (Bi4.9Eu0.1Fe0.9Ni0.1Ti3O15) showed enhanced photocatalytic activity and could be recycled simply by applying a magnet bar. This work may provide a basis for further developing new visible-light photocatalysts because the layer-structured Aurivillius phase has significant potential in elemental doping and further structural engineering applications.