Search Results (5)

The expansion of the livestock industry has led to an increase in biogas slurry discharge, which contains high levels of nitrogen (N) and phosphorous (P). Struvite precipitation is an effective method for the recovery of N and P from biogas slurry, and the recovered N and P can be applied as a slow-release fertilizer in agricultural production. To form an industrial chain for struvite recovery and application in agriculture, we investigated the factors affecting struvite recovery from biogas slurry generated on a pig farm and evaluated its efficacy as a fertilizer. The N and P recovery efficiency was higher when magnesium chloride (MgCl₂) was used as a magnesium (Mg) source compared with magnesium oxide (MgO), and the optimal reaction conditions were pH 10, a reaction time of 20 min, a stirring rate of 200 rpm, and a Mg/P/N ratio of 1.2:1.0:1.0, which achieved N and P recovery rates of 81.83% and 99.67%, respectively. To further investigate the commercial utility of using struvite recovered from biogas slurry as a fertilizer, the growth and content of nutrients in two common vegetables in China were measured. The vegetable quality-related parameters of bock choy (Brassica chinensis) improved as the proportion of struvite in the fertilizer increased. Fresh weight, soluble sugar, and soluble protein increased by 194.47%, 46.13%, and 82.42%, respectively. The quality-related parameters of water celery (Oenanthe javanica (Blume) DC.) increased with an increasing proportion of struvite (27.90 mg·g⁻¹ soluble sugar and 42.20 mg·g⁻¹ soluble protein). The application of struvite precipitated from biogas slurry in plant cultivation shows great potential and lays a solid foundation for the resourceful recovery and utilization of biogas slurry. Full article

Cadmium ion (Cd²⁺) stress is a major abiotic stressor affecting plant photosynthesis. However, the impact of sustained high-concentration Cd stress on the photosynthetic electron transport chain of aquatic plants is currently unclear. Here, prompt fluorescence (PF), delayed fluorescence (DF), and P700 signals were simultaneously measured to investigate the effect of Cd stress on photosynthesis in water dropwort [Oenanthe javanica (Blume) DC.]. We aimed to elucidate how Cd stress continuously affects the electron transport chain in this species. The PF analysis showed that with prolonged Cd stress, the F_J, F_I and F_P steadily decreased, accompanied by a positive shift in the K-band and L-band. Moreover, JIP-test parameters, including TR_O/ABS, ABS/CS_O, TR_O/CS_O and PI_ABS, were significantly reduced. The P700 signals showed that exposure to Cd stress hindered both the fast decrease and slow increase phases of the MR transient, ultimately resulting in a gradual reduction in both V_PSI and V_PSII−PSI. The DF analysis showed a gradual decrease in the I₁ and I₂ values as the duration of stress from Cd increased. The above results suggested that Cd stress affected the photosynthetic electron transport in water dropwort by influencing the amount of active PSII and PSI, primarily affecting PSII RCs in the early to mid-stages and PSI reductive activity in the later stage. Full article

Oenanthe javanica (OJ) is a perennial herb that grows wildly or is cultivated in Asia, and it is used as food or in traditional medicine. The antioxidant and anti-inflammatory effects of OJ-derived materials have been extensively explored previously, but their effects on the cytotoxicity of air pollution are currently unknown. Therefore, the present study aimed to evaluate the effect of the hot water extract of OJ on atmospheric particulate matter 10 (PM₁₀)-induced cytotoxicity and oxidative damage in human HaCaT keratinocytes, and to identify its active ingredient and mechanism of action. When the hot water extract of OJ was divided into methylene chloride, ethyl acetate (EA), n-butanol (BA), and water fractions, caffeic acid was enriched in the EA fraction and chlorogenic acid was enriched in the BA fraction. PM₁₀ increased reactive oxygen species (ROS) production, lipid peroxidation, protein carbonylation, and inflammatory prostaglandin (PG) E₂ production in cells. The BA fraction reduced the PM₁₀-induced ROS production in cells more effectively than the total extract and other solvent fractions. Chlorogenic acid was more effective in reducing ROS levels than caffeic acid and N-acetyl cysteine (NAC). Chlorogenic acid attenuated the increase in lipid peroxidation and the PG E₂ production of cells due to PM₁₀ exposure. Of the genes involved in PG E₂ production, phospholipase A2 group IVA (PLA2G4A), Prostaglandin-endoperoxide synthase 1 (PTGS1), and 2 (PTGS2) were transcriptionally up-regulated by PM₁₀, whereas phospholipase A2 group IIA (PLA2G2A) was down-regulated and prostaglandin E synthetase 1 (PTGES1) and 2 (PTGES2) were a little altered. The PM₁₀-induced increase in PLA2G4A mRNA was alleviated by chlorogenic acid and NAC. Accordingly, PM₁₀ increased the expression levels of cytosolic phospholipase A2 (cPLA2) protein and its phosphorylated form, which were attenuated by chlorogenic acid and NAC. Thus, chlorogenic acid may attenuate the PM₁₀-induced PG E₂ production through the suppression of PLA2G4A mRNA and cPLA2 protein expressions. This study suggests that chlorogenic acid contained in OJ extract may help alleviate the oxidative damage to and inflammatory responses of the skin cells due to exposure to air pollutants. Full article

Water dropwort (Oenanthe javanica (Blume) DC.) is an important vegetable crop. Nutrient liquid culture has become an important cultivation method in the production of water dropwort. However, the effects of different nutrient solution cultivation methods on the growth and quality of water dropwort remains unclear. In this study, to screen the most suitable nutrient solution formula for the cultivation of water dropwort, the effects of different nutrient solution formulas (Hoagland, Cooper, Dutch greenhouse, Garden-style, Yamasaki and SCAU) on plant physiological and quality characteristics are investigated. The plant height, root length, water content (%), distribution rate of dry matter (%), chlorophyll, VC, flavonoid, total phenolic, DPPH and dietary fiber of water dropwort under different nutrient solutions were determined. According to the analytic hierarchy process (AHP) of the growth index and quality index of water dropwort under different nutrient solutions, the Yamazaki nutrient solution was considered to be the most suitable nutrient solution formula for water dropwort. To further confirm the differences of water dropwort under nutrient solution culture and soil culture, the broadly targeted metabolomics were performed. A total of 485 metabolites were detected in water dropwort under optimal nutrient solution and soil cultivation. Metabolomics analysis showed that flavonoids were the most abundant differential accumulated metabolites, and most flavonoids were up-regulated. A qRT-PCR assay indicated that the structural genes of the flavonoid biosynthesis pathway (PAL, C4H, CHS, CHI, F3H, DFR, UFGT) were significantly higher under the Yamasaki nutrient solution treatment. The current study provided a theoretical basis and technical guidance for the nutrient solution cultivation of water dropwort. Meanwhile, this study provides new insights into the study of flavonoids in water dropwort. Full article

To investigate the role and microorganism-related mechanisms of macrophytes and assess the feasibility of Oenanthe javanica (Blume) DC. in promoting nitrogen removal in free-water surface constructed wetlands (FWS-CWS) under low temperatures (<10 °C), pilot-scale FWS-CWS, planted with O. javanica, were set up and run for batch wastewater treatment in eastern China during winter. The presence of macrophytes observably improved the removal rates of ammonia nitrogen (65%–71%) and total nitrogen (41%–48%) (p < 0.05), with a sharp increase in chemical oxygen demand concentrations (about 3–4 times). Compared to the unplanted systems, the planted systems not only exhibited higher richness and diversity of microorganisms, but also significantly higher abundances of bacteria, ammonia monooxygenase gene (amoA), nitrous oxide reductase gene (nosZ), dissimilatory cd1-containing nitrite reductase gene (nirS), and dissimilatory copper-containing nitrite reductase gene (nirK) in the substrate. Meanwhile, the analysis of the microbial community composition further revealed significant differences. The results indicate that enhanced abundances of microorganisms, and the key functional genes involved with nitrogen metabolism in the planted systems played critical roles in nitrogen removal from wastewater in FWS-CWS. Furthermore, abundant carbon release from the wetland macrophytes could potentially aid nitrogen removal in FWS-CWS during winter. Full article