ABSTRACT
Global warming and pesticide contamination are two stressors of high concern, but their combined effects on freshwater biota are controversial. This study investigated the combined effects of warming and imidacloprid (IMI) on survival (measured as life expectancy at hatching), reproduction (net reproductive rate), population growth (intrinsic rate of population increase) and sexual reproduction (proportion of sexual offspring) of Brachionus calyciflorus using a life table experiment. The results showed that compared with controls, treatments with IMI at 50-100 mg/L significantly decreased survival, reproduction and population growth of the rotifers at 20â. The inhibiting effect at higher IMI concentrations on survival increased with increasing temperatures, but those on reproduction and population growth increased only when the temperature increased from 25â to 30â. The proportion of sexual offspring decreased with increasing temperatures. When monitoring the ecological effects of pollutants, environmental temperature and the possible adaptation of rotifers to it should be taken into consideration.
Subject(s)
Rotifera , Water Pollutants, Chemical , Animals , Population Growth , Water Pollutants, Chemical/analysis , ReproductionABSTRACT
The composition of the rhizospheric and endophytic bacteria Phragmites australis in spring and summer around the Qiananling iron tailings reservoir in the Huairou District of Beijing was studied using Illumina high-throughput sequencing technology. Sequencing identified 40 phyla, and Proteobateria and Actinobacteria were the dominant phyla in all samples, accounting for more than 80% of the sequences in all samples. At the genus level, Pseudoarthrobacter was dominant. α-diversity analysis showed that species richness(Sobs, Chao) and species diversity indexes(Shannon, PD) of the rhizosphere soil microorganisms were significantly higher than those of endophytes. The maximum and minimum differences of the Sobs, Chao, Shannon, PD indexes were 1336, 1582.24, 6.48, and 81.18, respectively. ß-diversity analysis indicated that there were significant differences in the community compositions of rhizosphere soil microorganisms and root endophytes, while now notable differences were observed between samples in different seasons. In addition, the dominant strains in each sample(such as Pseudomonas, Arthrobacter, and Streptomyces) were highly resistant to heavy metals. Among the 774 genera, a total of 250 genera coexisted in four types of samples, indicating that the microbial community composition of different samples had some degree of similarity. Correlation analysis between soil physical and chemical properties showed that Ni, Fe, available phosphorus, effective sulphur, and organic matter were significantly related to the microbial communities. Through the prediction of COG function, it was found that the microbial metabolic functions(i.e., energy production and conversion, amino acid transport and metabolism, carbohydrate transport and metabolism, inorganic ion transport, and metabolism) were abundant.
Subject(s)
Iron , Soil Microbiology , Bacteria/genetics , Poaceae , Rhizosphere , SoilABSTRACT
The Rh(III)-catalyzed dual directing group assisted C-H activation/annulation of 3-arylisoxazolones with propargyl alcohols has been developed, which expands the application scope of isoxazolones in organic synthesis. This protocol also worked well with 3-aryl-1,4,2-dioxazol-5-ones to produce synthetically and biologically important 4-arylisoquinolones.
