ABSTRACT
An environmental and sensitive sample pretreatment method was established and combined with high-performance liquid chromatography (HPLC) for the analysis of tetracycline hydrochloride (TC) in feed water and lake water. One element small molecule alcohol-salt aqueous two-phase system (ATPS) cannot effectively adjust the polarity of the system, but binary small molecule alcohol-salt ATPS can adjust the polarity and improve the extraction efficiency of antibiotics. In this work, a binary ATPS based on ethanol +2-propanol + (NH4 )2 SO4 system was formed and applied to the separation and purification of TC in real water samples. The influence factors on partition behaviors of TC were discussed, including the types and the concentration of phase salts, the volume ratio of alcohol, the pH value, extraction temperature, and the standing time. The response surface methodology was used to determine the best experimental conditions for multi-factor experiments. Under this optimal condition, the extraction efficiency of TC reached 95.7%. This new method is considered to have significant application in the divorce of antibiotics.
ABSTRACT
We conducted a field investigation at 400 10 m×10 m quadrats in a 4-hm2 plot of mixed forest dominated by pine (Pinus tabuliformis) and oak (Quercus wutaishanica), which was established in 2011 in the Lingkong Mountain of Shanxi Province, China. The community characteristics in the year of 2016 were analyzed. The digital hemisphere photograph (DHP) approach was employed to measure the canopy structure and the understory light parameters. The results showed that a total of 5558 individuals of trees of 25 species from 15 genera and 10 families were recorded. The canopy openness (CO) varied from 15.0% to 25.0%, the leaf area index (LAI) varied from 1.5 to 2.5, and the understory light parameters varied from 10.0% to 30.0%. The distribution of dominant species drove the canopy structure and the undergrowth light factors. The canopy structure defined the impacts of light factors in the forest. The leaf area index was more optimal in describing the canopy’s dynamic function. The canopy openness and leaf area index were negatively correlated to understory light availability, especially to the abundance of the incident rays of diffused light. Since the canopy structure was relatively uniform in the temperate pine-oak mixed forest, the understory light spots generally distributed in clusters. The tree species and canopy structure had significant effects on light environment in the forest.
Subject(s)
Environmental Monitoring , Forests , Pinus , Quercus , China , TreesABSTRACT
In this study, investigation on plant community was conducted in Heyeping subalpine meadow of Luya Mountain in Shanxi Province of China. The importance values of 36 herbaceous species, α diversity index, phylogenetic diversity index, as well as their correlations were investigated. The results showed that the species diversity of the subalpine meadow was uniformly distributed. Species richness was higher in marginal areas, indicating an 'edge effect'. The phylogenetic structure of four plots was convergent and that of 12 plots was dispersive. The phylogenetic diversity index (PD) was positively correlated with the Petrick index, Simpson index and Shannon index, while there was no significant correlation of either the net relatedness index (NRI) or the nearest taxon index (NTI) to the α diversity indices.
Subject(s)
Biodiversity , Grassland , Phylogeny , China , Ecosystem , PlantsABSTRACT
Using the plant survivorship theory, the age structure, and the relationship between tree height and diameter (DBH) of Quercus wutaishanica population in Lingkong Mountain were analyzed, and the static life table was compiled and the survival curve plotted. The shuttle shape in age structure of Q. wutaishanica population suggested its temporal stability. The linear regression significantly fitted the positive correlation between tree height and DBH. The maximal life expectancy was observed among the trees beyond the age of the highest mortality and coincided with the lowest point of mortality density, suggesting the strong vitality of the seedlings and young trees that survived in the natural selection and intraspecific competition. The population stability of the Q. wutaishanica population was characterized by the Deevey-II of the survival curve. The dynamic pattern was characterized by the recession in the early phase, growth in the intermediate phase, and stability in the latter phase.
