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安全是旅游业的生命线,是游客在旅游过程中首要关心的问题,对旅游目的地的可持续发展具有重要意义。为了探讨游客安全研究中存在的问题及发展方向,在参阅研究文献的基础上,从游客安全意识、成因、评估和保障等方面,对国内外游客安全研究进展进行了评述。 相似文献
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The present study was to isolate and identify a potent algicidal compound from extract of Salvia miltiorrhiza and study the potential inhibition mechanism on Microcystis aeruginosa. Column chromatography and bioassay-guided fractionation methods were carried out to yield neo-przewaquinone A, which was identified by spectral analysis. The EC50 of neo-przewaquinone A on M. aeruginosa were 4.68 mg L−1. In addition, neo-przewaquinone A showed relatively higher security on Chlorella pyrenoidosa and Scenedesmus obliquus, with the EC50 values of 14.78 and 10.37 mg L−1, respectively. For the potential inhibition mechanisms, neo-przewaquinone A caused M. aeruginosa cells morphologic damage or lysis, increased malondialdehyde content and decreased the soluble protein content, total antioxidant and superoxide dismutase activity, and significantly inhibited three photosynthesis-related genes (psaB, psbD, and rbcL). The results demonstrated the algicidal effect of neo-przewaquinone A on M. aeruginosa and provided the possible inhibition mechanisms. 相似文献
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连片生态浮床对微污染河水的净化效果 总被引:1,自引:1,他引:0
选取漕桥河的支流庙尖浜作为实验河段,以睡莲(Nymphaea alba)、菖蒲(Acorus calamus Linn)和水芹(Oenan-the javanica(Blume)DC)作为微污染水体净化的浮床植物,研究连片生态浮床的净化能力随季节的变化和浮床面积对连片生态浮床净化能力的影响。结果显示,秋-冬-春季节内植物的净化能力随季节变化呈"U"型,相应的河水水质的变化呈一个倒置的"U"型;在一定营养负荷和植物正常生长状况下,沿水流方向,氮、磷含量随浮床面积的增加而降低——春季时,随浮床面积增加,菖蒲区对TN的去除率由8.6%增加到26.7%,TP的去除率由17.1%增加到58.2%,水芹区对TN和TP的去除率最高可达22.0%和28.0%。研究表明连片生态浮床是河道水质改善的有效可行的方法之一,可为太湖入湖河流的营养物质控制提供科学依据。 相似文献
158.
Salicylic acid involved in the regulation of nutrient elements uptake and oxidative stress in Vallisneria natans (Lour.) Hara under Pb stress 总被引:1,自引:0,他引:1
In this study, the alterations in nutrient elements content, reactive oxygen species level and antioxidant response were studied in leaves of Vallisneria natans (Lour.) Hara exposed to salicylic acid (SA, 10 or 100 μM), or Pb (50 μM) or their combinations for 4 d. No significant alterations in Mn and Ca content were observed but content of Cu, Zn, Fe and P decreased in plants exposed to SA alone. SA application inhibited the uptake of Pb and partially reversed Pb-induced the alterations in Mn, Ca and Fe content in leaves of V. natans exposed to 50 μM Pb. The decreased chlorophyll (a + b) and increased malondialdehyde and O2− and H2O2 content were detected in plants exposed to 100 μM SA, 50 μM Pb, 10 μM SA + 50 μM Pb or 100 μM SA + 50 μM Pb. Application SA partially inhibited Pb-induced the increase of malondialdehyde, O2− and H2O2 content. 100 μM SA decreased the activity of NADH oxidase and the content of non-protein thiols, carotenoids and ascorbic acid and increased the content of dehydroascorbate in plants treated with or without Pb. SA alone decreased the ascorbate peroxidase activity and increased the catalase and peroxidase activity, while SA application increased catalase activity but had no significant effect on ascorbate peroxidase and peroxidase activity in V. natans exposed to Pb. The results indicate that SA involves in the regulation of Pb uptake, nutrient balance and oxidative stress. 相似文献
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The dissipation of carbendazim and chloramphenicol alone and in combination and their effects on soil fungal:bacterial ratios and soil enzyme activities were investigated. The results revealed that carbendazim dissipation was little affected by chloramphenicol, whereas chloramphenicol dissipation was found to be retarded significantly by the presence of carbendazim. The inhibitory effect of carbendazim on the fungal:bacterial ratios was increased by the presence of chloramphenicol, and the inhibitory effect of chloramphenicol on neutral phosphatase was increased by the presence of carbendazim. Carbendazim increased soil catalase and urease activities, but this increase was partially diminished by the presence of chloramphenicol. Little interaction was observed between carbendazim and chloramphenicol with regard to their influence on soil invertase. The results obtained in this study suggest that combinations of fungicides and antibiotics may alter the compounds’ individual behaviors in soil and their effects on soil enzymes. 相似文献
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