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Previous studies on negative air ion (NAI), an important index for evaluating atmospheric quality, has been focused on field observation, and less on NAI under controlled condition. In this study, the NAI concentrations of different individual abundance of Liquidambar formosana and Taxus wallichiana were continuously monitored under the same climatic conditions in Hushan Experimental Base of Qianjiangyuan Forest Ecosystem Research Station, Zhejiang Province from September to October 2018. Changes of NAI concentration were monitored under different levels of air temperature and relative humidity to explore the effects of forest vegetation and meteorological factors on NAI. The results showed that both species significantly increased the NAI concentration. Plant abundance was positively correlated with the NAI concentration, and the relationship between them fitted the quadratic function with the plant abundance ranging from 0 to 50. The fitting equations for L. formosana and T. wallichiana were as follows: y=-0.0484x2+4.7005x+345.7 (R2=0.62), y=-0.0207x2+1.9189x+365.91 (R2=0.34). There was a significant positive correlation between NAI concentration and air temperature in the range of 5-30 â with a fitting equation of y=0.4139x2-9.2229x+89.919 (R2=0.92). The NAI concentration and the relative humidity of air in the range of 56%-87% were positively correlated with a fitting equation of y=3.6508e0.0526x(R2=0.94).
Assuntos
Ecossistema , Conceitos Meteorológicos , Temperatura , Umidade , ÍonsRESUMO
BACKGROUND: Stemonae radix has been applied in traditional Chinese medicine for centuries. Alkaloids are the main active ingredient in stemonae radix, so their composition and concentration levels are directly linked to clinic effects. OBJECTIVE: The objective was to develop an analytical method with multiple markers for quality survey of commercial stemonae radix. MATERIALS AND METHODS: A method for simultaneous determination of six compounds in commercial stemonae radix was performed using solid-phase extraction and high-performance liquid chromatography coupled with evaporative light scattering detector. The separation was carried out on an Agilent TC-C18 column with 0.1% acetonitrile solution of triethylamine aqueous solution and acetonitrile as the mobile phase under gradient elution within 70 min. The hierarchical clustering analysis (HCA) was successfully used to classify the samples in accordance with their chemical constituents. RESULTS: Linearity (R(2) > 0.9990), intra- and inter-day precision (relative standard deviations <4%), limit of detection (0.011-0.086 µg/mL), limit of quantification (0.033-0.259 µg/mL) of the six alkaloids were determined, and the recoveries were between 96.6% and 103.7%. The method was successfully applied to analysis 36 batches of commercial stemonae radix. All the samples could be classified into five clusters by HCA. CONCLUSION: This article provides an accurate and simple analytical method for quality survey of commercial stemonae radix. Because of the significant chemical variations, careful selection of Stemona sources with obvious antitussive value but devoid of croomine followed by good agricultural practice and good manufacturing practice process is suggested.
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The performance of a partition-limited model on prediction of four PAHs (acenaphthene, fluorene, phenanthrene and pyrene) uptake by ryegrass simultaneously was evaluated using a hydroponic system. Results suggest that the model has a good performance on prediction of PAHs uptake. However, the model focused on root translocation only, while excluded foliar uptake, which resulted in a poor performance on prediction of PAHs in shoots. The differences of simulated and experimented concentrations of PAHs were less than 57.4% for roots and less than 98.5% for shoots respectively. If the influence of foliar uptake on the performance of the model was taken into account, the differences for all the four PAHs would be reduced significantly. Since the influence of foliar uptake increased with the increase of the hydrophobic property of the PAHs, the differences decreased with an order of pyrene> phenanthrene> fluorene> acenaphthene, among which the maximum difference for pyrene decreased from 98.5% down to 69.4%.
