Litter nitrogen concentration changes mediate effects of drought and plant species richness on litter decomposition.

Biodiversity loss, exotic plant invasion and climatic change are three important global changes that can affect litter decomposition. These effects may be interactive and these global changes thus need to be considered simultaneously. Here, we assembled herbaceous plant communities with five species richness levels (1, 2, 4, 8 or 16) and subjected them to a drought treatment (no, moderate or intensive drought) that was factorially combined with an invasion treatment (presence or absence of the non-native Symphyotrichum subulatum).

Denitrifying bacterial community dominantly drove nitrogen removals in vertical flow constructed wetlands as impacted by macrophyte planting patterns.

The study aims to identify relations of denitrifying bacterial and fungal communities to nitrogen removals in vertical flow wetland microcosms (VFWMs) using four macrophyte species (Iris pseudacorus, Canna glauca, Scirpus validus and Cyperus alternifolius) and three species richness levels (unplanted, monocultured and 4-species mixture) as fixed factors. Results showed that among four macrophyte species, only Canna glauca planting significantly decreased nitrate removal by 87.7% in the VFWMs.

Comparison of fungal communities among ten macrophyte rhizospheres.

The fungal community composition, size and several physico-chemical properties were individually investigated in ten macrophyte rhizospheric substrates using nested PCR-denaturing gradient gel electrophoresis and soil chemical methods. Results indicated that both Dothideomycetes and Sordariomycetes were dominant fungi in macrophyte rhizospheric substrates, and denitrifying fungi (Fusarium graminearum) was found in nine of ten macrophyte rhizospheres. Fungal Shannon-Wiener diversity index (H) and richness (S) in Thalia dealbata, Typha latifolia, Iris hexagona and Hemerocallis aurantiaca rhizospheres were higher than those in other six rhizospheres.

Plant species diversity reduces NO but not CH emissions from constructed wetlands under high nitrogen levels.

Constructed wetlands (CWs) have been widely used for treating wastewater. CWs also are the sources of greenhouse gas (GHG) due to high pollutant load. It has been reported that plant species diversity can enhance nitrogen (N) removal efficiency in CWs for treating wastewater.

Effects of phthalate ester treatment on seed germination and antioxidant enzyme activities of Phaseolus radiatus L.

Effects of di-(2-ethylhexyl) phthalate and di-n-butyl phthalate on seed germination rate and antioxidant enzymes activities of mung bean (Phaseolus radiatus L.) were investigated. Results showed that under the treatment with 10 mg/kg of phthalate esters (PAEs), superoxide dismutase (SOD), peroxidase and catalase (CAT) activities were higher than those of the control (p > 0.

Effects of monocot and dicot types and species richness in mesocosm constructed wetlands on removal of pollutants from wastewater.

The effects of planting type and species richness on removal of BOD5, COD, nitrogen and phosphorus were studied in mesocosms with monocot alone (M), dicot alone (D) and mixed planting of M+D, where each planting type had four species richness levels. Above- and below-ground plant biomasses increased with the M and M+D species richness as shown by one-way ANOVA. The M+D type had the highest above-ground biomass, whereas the M type had the highest below-ground biomass among planting types.

[Complex effects of simulated acid rain and Cu on the physiological characteristics of Paulownia fortunei and its detoxification mechanism].

A pot experiment was conducted to study the effects of simulated acid rain (pH 4.0, 5.0) and Cu (0-200 mg x kg(-1)) on the physiological characteristics of Paulownia fortunei and its detoxification mechanism.

Physiological responses and detoxific mechanisms to Pb, Zn, Cu and Cd in young seedlings of Paulownia fortunei.

Paulownia fortunei has been successfully used in the phytoremediation of many Pb/Zn mine tailings. However, seed germination and young seedlings of P. fortunei rarely occurred in these mine tailings.

Effects of plant diversity on nutrient retention and enzyme activities in a full-scale constructed wetland.

This study focused on the relationship between plant diversity (six species richness levels) and nutrient retention and enzyme activities associated with carbon, nitrogen and phosphorus cycling in a full-scale constructed wetland (CW) fed with post-treatment domestic wastewater. Effects of plant species richness on nutrient retention and enzyme activities were assessed using soil chemical and zymological methods, respectively. Retention of NH(4)-N and NO(3)-N in the wetland substrate increased with increasing species richness, while phosphorus retention significantly decreased under the richness level of 16 species per plot.

[Effects of Miscanthus floridulus on microbial biomass and basal respiration in heavy metals polluted soils].

Vegetation coverage is an important parameter in terrestrial ecological process, meteorological, and climatic models. By eliminating the errors from the precision of image classification and the noises of remote sensing images, and by using the actual data from fieldwork, this paper determined the maximum and minimum values of normalized difference vegetation index (NDVI), improved the sub-pixel model, and verified this model by calculating the vegetation coverage of Beijing. The results showed that the estimation value of the improved model was very close to the measurements, especially for the herbaceous plants whose vegetation types were the same but the densities were different.

[Oligotrophic bacteria and their applications in environmental science].

Oligotrophic bacteria are a group of microbes living in oligotrophic environments. Their diversity and biomass are dominant in biosphere, and thus, play an important role in biogeochemical cycles. Since 1980s, their oligotrophic mechanisms, responses to starvation, and roles in ecosystems have been one of the most advanced subjects in microbial ecological research.