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Histone deacetylases (HDACs) are important regulators that participate in plant growth and development. HISTONE DEACETYLASE 9(HDA9), HISTONE DEACETYLASE 6(HDA6) and FLOWERING LOCUS D(FLD) are reported to be involved in flowering regulation, stress response and other regulation in Arabidopsis, but whether and how there is a protein relationship between them in Chinese cabbage (Brassica rapaL. ssp. pekinensis) is still unknown. In this study, BrFLD, two members of BrHDA6, and BrHDA9were cloned from Brassica rapaand ubiquitously expressed in roots, stems, cauline leaves, flower buds and opening flowers. Those genes exhibited their highest transcript levels in cauline leaves and lowest levels in stems or flower buds. BrFLDand two BrHDA6swere highly induced by long-day photoperiod, but BrHDA9was highly induced by short-day. The genes are diel regulated and have different patterns across the photoperiods. Yeast two-hybrid assays and glutathione S-transferase (GST) pull-down assays revealed that the BrFLD protein interacts with the two BrHAD6 proteins but not with the BrHDA9 protein, and no interaction was detected between BrHDA9 and the two BrHDA6s. Further research showed that the SWIRM domain of BrFLD and the C-domain of BrHDA6 are the key domains involved in these interactions. This result suggested that HDAC genes are regulated by photoperiod and participate in autonomous pathway control flowering time through integration with FLD or regulate flowering independently of FLD.

Wet air oxidation (WAO) and catalytic wet air oxidation (CWAO) are efficient processes to degrade organic pollutants in water. In this paper, we especially reviewed the WAO and CWAO processes for phenolic compounds degradation. It provides a comprehensive introduction to the CWAO processes that could be beneficial to the scientists entering this field of research. The influence of different reaction parameters, such as temperature, oxygen pressure, pH, stirring speed are analyzed in detail; Homogenous catalysts and heterogeneous catalysts including carbon materials, transitional metal oxides and noble metals are extensively discussed, among which Cu based catalysts and Ru catalysts were shown to be the most active. Three different kinds of the reactor implemented for the CWAO (autoclave, packed bed and membrane reactors) are illustrated and compared. To enhance the degradation efficiency and reduce the cost of the CWAO process, biological degradation can be combined to develop an integrated technology.

The electro-peroxone (E-P) process normally exhibits low efficiency in organic degradation in acid solution due to the limited rate constant of the reaction between O3and H2O2(peroxone reaction). In this paper, a C3N4–Mn/CNT composite material was synthetized and characterized with XRD, FTIR, SEM and XPS. With the function of the C3N4–Mn/CNT catalyst, the substrate oxalic acid (OA) was completely degraded in the E-P process within 30 min at pH 3, while only 15% degradation could be achieved after 60 min without the catalyst. The comparison of different reaction systems using the C3N4–Mn/CNT catalyst confirmed that the catalyst promoted the peroxone reaction, rather than the catalytic ozonation or electro-Fenton like reaction. Correlating the XRD and XPS analysis with the degradation data using the C3N4–Mn/CNT catalyst, we deduced that Mn coordinated with nitrogen was the active site for the peroxone reaction. Furthermore, the catalyst showed good chemical and catalytic stability in five cycles of the E-P process for OA degradation.