Cloning of four DREB genes from Tibetan Sophora moorcroftiana and analysis of their expression during abiotic stress

Sophora moorcroftiana is an endemic, droughtresistant shrub that grows in Tibet and has some degree of resistance to salt, cold, heat, and drought. In the present study, four dehydration responsive element-binding（DREB） genes（Sm DREB1, Sm DREB2, Sm DREB and Sm DREB1） were isolated from S. moorcroftiana for the first time and their expression and proline content under abiotic stress were analyzed. Proline accumulated in seedlings under drought, salt, cold, and heat stress treatments. The four genes were variously expressed in response to the four abiotic stresses. Sm DREB1 was induced by drought, cold, and heat stresses; Sm DREB2 and Sm DREB4 were both induced by salt, cold, and heat stresses, whereas Sm DREB3 was induced by drought and heat stresses. Thus, these four genes may participate in conferring tolerance to these four abiotic stresses and are candidate genes for genetic engineering in the future.

Transport Patterns and Potential Sources of Atmospheric Pollution during the ⅩⅩⅣ Olympic Winter Games Period

The attainment of suitable ambient air quality standards is a matter of great concern for successfully hosting the ⅩⅩⅣ Olympic Winter Games(OWG). Transport patterns and potential sources of pollutants in Zhangjiakou(ZJK) were investigated using pollutant monitoring datasets and a dispersion model. The PM_(2.5) concentration during February in ZJK has increased slightly(28%) from 2018 to 2021, mostly owing to the shift of main potential source regions of west-central Inner Mongolia and Mongolian areas(2015–18) to the North China Plain and northern Shanxi Province(NCPS) after 2018.Using CO as an indicator, the relative contributions of the different regions to the receptor site(ZJK) were evaluated based on the source-receptor-relationship method(SRR) and an emission inventory. We found that the relative contribution of pollutants from NCPS increased from 33% to 68% during 2019–21. Central Inner Mongolia(CIM) also has an important impact on ZJK under unfavorable weather conditions. This study demonstrated that the effect of pollution control measures in the NCPS and CIM should be strengthened to ensure that the air quality meets the standard during the ⅩⅩⅣ OWG.

Development and evaluation of an online monitoring single-particle optical particle counter with polarization detection

We developed a single-particle optical particle counter with polarization detection(SOPC)for the real-time measurement of the optical size and depolarization ratio(defined as the ratio of the vertical component to the parallel component of backward scattering)of atmospheric particles,the polarization ratio(DR)value can reflect the irregularity of the particles.The SOPC can detect aerosol particles with size larger than 500 nm and the maximum particle count rate reaches~1.8×10^(5)particles per liter.The SOPC uses a modulated polarization laser to measure the optical size of particles according to forward scattering signal and the DR value of the particles by backward S and P signal components.The sampling rate of the SOPC was 106#/(sec·channel),and all the raw data were processed online.The calibration curve was obtained by polystyrene latex spheres with sizes of 0.5-10μm,and the average relative deviation of measurement was 3.96% for sub 3μm particles.T-matrix method calculations showed that the DR value of backscatter light at 120°could describe the variations in the aspect ratio of particles in the above size range.We performed insitu observations for the evaluation of the SOPC,the mass concentration constructed by the SOPC showed good agreement with the PM_(2.5)measurements in a nearby state-controlled monitoring site.This instrument could provide useful data for source appointment and regulations against air pollution.

Refractory black carbon aerosols in rainwater in the summer of 2019 in Beijing:Mass concentration,size distribution and wet scavenging ratio

Black carbon(BC)aerosols in the atmosphere play a significant role in climate systems due to their strong ability to absorb solar radiation.The lifetime of BC depends on atmospheric transport,aging and consequently on wet scavenging processes(in-cloud and below-cloud scavenging).In this study,sequential rainwater samples in eight rainfall events collected in 2 mm interval were measured by a tandem system including a single particle soot photometer(SP2)and a nebulizer.The results showed that the volume-weighted average(VWA)mass concentrations of refractory black carbon(rBC)in each rainfall event varied,ranging from 10.8 to 78.9μg/L.The highest rBC concentrations in the rainwater samples typically occurred in the first fraction from individual rainfall events.The geometric mean median mass-equivalent diameter(MMD)decreased under precipitation,indicating that rBC with larger sizes was relatively aged and preferentially removed by wet scavenging.A positive correlation(R2=0.73)between the VWA mass concentrations of rBC in rainwater and that in ambient air suggested the important contribution of scavenging process.Additionally,the contributions of in-cloud and below-cloud scavenging were distinguished and accounted for 74%and 26%to wet scavenging,respectively.The scavenging ratio of rBC particles was estimated to be 0.06 on average.This study provides helpful information for better understanding the mechanism of rBC wet scavenging and reducing the uncertainty of numerical simulations of the climate effects of rBC.

Cross-boundary transport and source apportionment for PM_(2.5) in a typical industrial city in the Hebei Province,China:A modeling study

Cross-boundary transport of air pollution is a difficult issue in pollution control for the North China Plain.In this study,an industrial district(Shahe City)with a large glass manufactur-ing sector was investigated to clarify the relative contribution of fine particulate matter(PM_(2.5))to the city's high levels of pollution.The Nest Air Quality Prediction Model System(NAQPMS),paired with Weather Research and Forecasting(WRF),was adopted and applied with a spatial resolution of 5 km.During the study period,the mean mass concentrations of PM_(2.5),SO_(2),and NO_(2)were observed to be 132.0,76.1,and 55.5μg/m^(3),respectively.The model reproduced the variations in pollutant concentrations in Shahe at an acceptable level.The simulation of online source-tagging revealed that pollutants emitted within a 50-km radius of downtown Shahe contributed 63.4%of the city's total PM_(2.5)concentration.This contribu-tion increased to 73.9±21.2%when unfavorable meteorological conditions(high relative hu-midity,weak wind,and low planetary boundary layer height)were present;such conditions are more frequently associated with severe pollution(PM_(2.5)≥250μg/m^(3)).The contribution from Shahe was 52.3±21.6%.The source apportionment results showed that industry(47%),transportation(10%),power(17%),and residential(26%)sectors were the most important sources of PM_(2.5)in Shahe.The glass factories(where chimney stack heights were normally<70 m)in Shahe contributed 32.1%of the total PM_(2.5)concentration in Shahe.With an in-crease in PM_(2.5)concentration,the emissions from glass factories accumulated vertically and narrowed horizontally.At times when pollution levels were severe,the horizontally influ-enced area mainly covered Shahe.Furthermore,sensitivity tests indicated that reducing emissions by 20%,40%,and 60% could lead to a decrease in themass concentration of PM_(2.5) of of 12.0%,23.8%,and 35.5%,respectively.