Sulfur poisoning is one of the most important factors deteriorating the purification efficiency of diesel exhaust after-treatment system, thus improving the sulfur resistibility of catalysts is imperative. Herein, ceria oxygen storage material was introduced into a sulfur-resistant titania by a co-precipitation method, and the sulfur resistibility and catalytic activity of prepared TiO₂-CeO₂ composite in the oxidation of diesel soluble organic fraction (SOF) were studied. Catalytic performance testing results show that the CeO₂ modification significantly improves the catalytic SOF purification efficiency of TiO₂-CeO₂ catalyst. SO₂ uptake and energy-dispersive X-ray (EDX) results suggest that the ceria doping does not debase the excellent sulfur resistibility of bare TiO₂, the prepared TiO₂-CeO₂ catalyst exhibits obviously better sulfur resistibility than the CeO₂ and commercial CeO₂-ZrO₂-Al₂O₃. X-ray powder diffraction (XRD) and Raman spectra indicate that cerium ions can enter into the TiO₂ lattice and not form complete CeO₂ crystals. X-ray photoelectron spectroscopy (XPS), H₂-temperature programmed reduction (H₂-TPR) and oxygen storage capacity (OSC) testing results imply that the addition of CeO₂ in TiO₂-CeO₂ catalyst can significantly enhance the surface oxygen concentration and oxygen storage capacity of TiO₂-CeO₂.

The sources and variation trend of ambient air pollutants, the duration of pollution process and the conditions for decontamination were analyzed in this essay based on the ambient air pollutants data, PM2.5 source analysis data and meteorological factors in Nanchong City during 2014 to 2019. The results indicated that the concentrated discharge of fireworks on New Year’s Eve was the main reason for the sharp deterioration of the ambient air quality. PM2.5 and PM10 concentrations increased significantly after fireworks were set off, and the peak value appeared at about 02:00 on the Lunar New Year’s Day, but the value of PM2.5/PM10 did not change significantly. The concentration of SO2 in gaseous pollutants was slightly affected by fireworks, while NO2, CO and O3 were not affected basically. Having been affected by fireworks, the concentrations and percentages of K+, Cl- and Mg2+ of the water-solubility ions in PM2.5 significantly increased at the 0.01 level. Meanwhile, the concentrations and percentages of the metal elements, including Cu, Pb, Mg, Al, K and Ba, significantly increased at the 0.05 level. Restricted to the topography and meteorological factors, the duration of the pollution was prolonged.

The evolution and expression of floral traits are responses to selection pressure from biotic and abiotic factors. Although floral traits significantly vary among environments, the flower remains unchanged. We aimed to understand the adaptation of Epimedium chlorandrum of floral traits to a frequently nocturnally rainy and wet environment and the roles of floral traits in pollination and reproduction. We observed flowering phenology, measured floral characteristics including the number of pollen grains and ovules per flower, measured pollen viability and stigma receptivity, tested the volume and sugar concentration of nectar, and conducted flower-visit observations in this species. Different pollination treatments were performed to characterize the breeding system. The inner sepals and highly curved longer spurs of E. chlorandrum jointly formed an umbrella that shielded the anthers and stigma from rain wash and prevented nectar dilution. E. chlorandrum was visited by six species, while Bombus trifasciatus was the only effective pollinator and fed on the nectar. One flower secreted approximately 17.06 μL of nectar with a 29.19 g/100 ml sugar concentration, and the pollination efficiency of B. trifasciatus was positively associated with the nectar sugar concentration. The self- and open-pollination treatments resulted in fewer fertile seeds than the cross-pollination treatment. In contrast, the autonomous self-pollination treatment failed to yield fertile seeds. In summary, pollen limitation caused by harsh weather and pollinator shortage occurred during the pollination process of E. chlorandrum, which was partially alleviated by self-compatibility.

To understand the reproductive strategies of the typically introduced plant Hibiscus mutabilis and to compare the pollination efficiency of its different pollinators, we observed, measured, and recorded the flowering dynamics, floral traits, and visiting insects of H. mutabilis. Furthermore, we compared the body size, visitation rate, and pollination efficiency of the pollination insects of H. mutabilis. The results indicated that, despite exhibiting specialized moth pollination characteristics based on similarities in flower features to other moth-pollinated species, H. mutabilis actually presented a generalized pollination system. The nectar of H. mutabilis attracted a variety of insects to provide pollination services, a total of five flower visitors, one moth species (Macroglossum pyrrhosticta), and four bee species (Xylocopa appendiculata, Xylocopa dissimilis, Bombus breviceps, and Apis mellifera), were found to provide pollination services for H. mutabilis. The pollination efficiency of these pollinators was related to the parts of their body in contact with the stamens and stigmas of flowers. Although M. pyrrhosticta was larger in size and its visitation frequency in our field observations was higher, its pollination efficiency was lower. This was due to the small part of its body (proboscis) contacting the two sexual organs of H. mutabilis while visiting flowers, resulting in a low amount of pollen being transferred and deposited. In contrast, the bee pollinators’ proboscis was significantly shorter than that of M. pyrrhosticta, and it must enter the flower to suck the nectar that is hidden deeply inside the base of the flower. Therefore, the body parts of bee pollinators in contact with the two sexual organs of H. mutabilis were larger than M. pyrrhosticta in the process of visiting flowers, and the pollination efficiencies were significantly higher than those of M. pyrrhosticta. In addition, larger bee pollinators have higher pollination efficiency. As a result, H. mutabilis suffered from pollen limitation due to the pollination efficiencies of the moth pollinators in the introduced habitats, but it compensated by attracting more species of bee pollinators.

In order to explore the synergistic effect of biochar and arbuscular mycorrhizal (AM) fungi on plant growth under cadmium (Cd) stress, a pot experiment was conducted to investigate the effects of biochar application and AM fungal inoculation on mulberry (Morus alba) seedling growth, mineral element absorption, Cd uptake, soil pH and Cd availability under Cd contamination at 2 levels (0 and 4 mg⋅kg⁻¹). The results showed that biochar application could increase the mycorrhizal infection rate of AM fungi. Biochar application and AM fungal inoculation alone or their combination could all increase plant height, biomass, mineral element content and soil pH, while reduce Cd bioavailability in soil and Cd uptake by mulberry seedlings. The effects of biochar application in increasing soil pH and N and K uptake were better compared with AM fungal inoculation. However, AM fungal inoculation presented better effects in promoting mulberry seedling growth, improving P, Ca and Mg absorption by mulberry seedlings, and reducing Cd availability in soil and Cd absorption by mulberry seedlings. The combination of biochar application and AM fungal inoculation obtained the best effect. Under Cd level of 4 mg⋅kg⁻¹, the combination of biochar application and AM fungal inoculation increased plant height and N, P, K, Ca and Mg contents in mulberry leaves by 43.28%, 125.56%, 178.48%, 3.63%, 181.04% and 128.04%, respectively. While, Cd concentration in the roots, stems and leaves of mulberry seedlings decreased by 46.48%, 67.86% and 58.97%, respectively. Moreover, pH increased by 5.33%, while Cd availability in soil decreased by 69.53%. In conclusion, biochar and AM fungi alone or their combination can all reduce Cd stress, and promote plant growth and mineral element absorption. The combination of biochar and AM fungi presents the best effect. Biochar combined with AM fungi can be used as an effective measure for ecological restoration of degraded soil and agricultural production safety.