Geographic patterns of Lucanus (Coleoptera: Lucanidae) species diversity and environmental determinants in China.

Clarifying the geographic patterns of species diversity and the determinant factors can provide essential information for species conservation and management. Stag beetles (Coleoptera: Lucanidae) of Lucanus are important saproxylic insects and can be used for biomonitoring forests. Most of Lucanus species are facing conservation concerns due to their limited distribution and fragmented habitats, particularly in China, which has the richest species diversity of this genus. The distribution patterns of species diversity of Lucanus at large spatial scales remain portly understood. We studied the distribution patterns of Lucanus and its environmental and geographic determinants in China. Distribution data for 72 species and subspecies were examined. All these species are distributed in southern China except for Lucanus maculifemoratus dybowskyi, which is mainly distributed in north China. The hotspot for Lucanus in China is southeastern Tibet. Our study indicated that the species richness of Lucanus in China was shaped by the precipitation of the wettest and driest month, net primary productivity, digital elevation model, and latitude at a large scale. These variables collectively explained 56.2% of the variation in species richness; precipitation contributed the most (44.1%). Our results provide valuable insights to improve the conservation of Lucanus and can contribute to furthering our understanding of the biogeography of stag beetles in China.

Analysis of influencing factors on soil Zn content using generalized additive model.

Soil zinc (Zn) plays a crucial role in plant growth, but excessive accumulation in the environment may lead to air, water and soil pollution. It is affected by various chemical, environmental and spatial factors. Therefore, it is important to identify the factors influencing Zn content in the landscape. The main motivation for this study is to determine the suitability of a generalized additive model (GAM) to describe change in soil Zn content due to influencing factors. A total of 1497 soil nutrient samples were collected in Fangshan District, Beijing, China. Organic matter (OM), available phosphorus (AP), available potassium (AK), alkali-hydrolyzed nitrogen (AHN) and slowly available potassium (SAK) are considered. The relationship between Zn, nutrients and geographic location (latitude & longitude) is investigated using the GAM. More precisely, the Akaike information criterion (AIC) is used to select influencing factors on Zn content and cross-validated to avoid overfitting of the multivariate model. The results show that Zn content reaches its maximum at latitude 39.8°N and longitude 115.9°E. Zinc content increases as AP increases to 150 mg/kg. When OM content is greater than 90 g/kg, Zinc content decreases with an increase in OM content. Factors that affected Zn content, in descending order of significance derived from deviance explained and adjustment coefficient of determination (Adj.R2) were AP, latitude, AHN, AK and OM. Moreover, the interactions between latitude and longitude, AHN and AP, OM and AK have significant impact on Zn.

[Using extraction of red edge position to validate consistency of hyperspectral imaging and non-imaging data].

Using Pushbroom imaging spectrometer (PIS) and FieldSpec ProFR2500 (ASD), spectral reflectances of winter wheat and maize at different stages were collected synchronously. In order to validate the reliability of imaging spectral data, the red edge position of hyperspectral data for PIS and ASD were extracted by different algorithms, respectively. The following results were obtained: (1) The original spectrum of both instruments had high inosculation in red light region (670-740 nm); (2) With the spectra collected under laboratory condition (maize leaf), the extracted red edge position was is concentrated between 700 and 720 nm for the two instruments; (3) With the spectra collected undre field condition (wheat leaf), the extracted red edge position for PIS and ASD were different, the red edge position of PIS data was in 760 nm, while it was in 720 nm for ASD data. The main reason might be that the imaging spectral data were influenced by oxygen absorbtion; (4) the red edge rangeability of PIS and ASD were different, but the trends were the same. The above results could provide some references for hyperspectral imaging data's extensive application.

[Investigation of the hyperspectral image characteristics of wheat leaves under different stress].

The diagnosis of growing status and vigor of crops under various stresses is an important step in precision agriculture. Hyperspectral imaging technology has the advantage of providing both spectral and spatial information simultaneously, and has become a research hot spot. In the present study, auto-development of the pushbroom imaging spectrometer (PIS) was utilized to collect hyperspectral images of wheat leaves which suffer from shortage of nutrient, pest and disease stress. The hyperspectral cube was processed by the method of pixel average step by step to highlight the spectral characteristics, which facilitate the analysis based on the differences of leaves reflectance. The results showed that the hyperspectra of leaves from different layers can display nutrient differences, and recognize intuitively different stress extent by imaging figures. With the 2 nanometer spectral resolution and millimeter level spatial resolution of PIS, the number of disease spot can be qualitatively calculated when crop is infected with diseases, and, the area of plant disease could also be quantitatively analyzed; when crop suffered from pest and insect, the spectral information of leaves with single aphid and aphids can be detected by PIS, which provides a new means to quantitatively detect the aphid destroying of wheat leaf. The present study demonstrated that hyperspecral imaging has a great potential in quantitative and qualitative analysis of crop growth.

[Study on genetic polymorphisms of 13 SNP loci in Guangxi Zhuang population of China].

OBJECTIVE: The fluorescence labeled multi-PCR system was applied to investigate the allele frequency of the 13 single nucleotide polymorphism (SNP) in 314 Guangxi Zhuang populations, and to evaluate their application value in forensic medicine. METHODS: Thirteen autosomal diallelic SNP loci were selected and the SNP genotyping system of fragment length discrepant allele specific fluorescence labeled multi-PCR technique was applied to investigate their allele frequency distribution in Guangxi Zhuang population. RESULTS: The allele frequencies of the 13 single nucleotide pdymorphism (SNP) in Guangxi Zhuang population were obtained, which shows that the allele frequency distribution is in accordance with Hardy-Weinberg equilibrium. Their heterozygosity was between 0.2166 and 0.5478, the polymorphism information content was between 0.2084 and 0.3750, their cumulate discrimination probability was 99.99%, and the cumulate exclusion power was 87.71%. CONCLUSION: Several SNP loci could be genotyped simultaneously using the fluorescence labeled fragment length discrepant multiplex-PCR technique; the 13 SNP loci have a highly applicable value in the field of forensic personal identification.

[A comparative study on genetic polymorphism and genetic relationship of 13 SNPs in three Chinese populations].

Using the fluorescence labeled capillary electrophoresis of multi-PCR technique, the single nucleotide polymorphism (SNP) typing system of fragment length discrepant allele specific fluorescence labeled multi-PCR technique is established based on the principle of allele-specific PCR. The typing of the 13 SNP loci can be completed simultaneously according to the length of PCR products and the number of product peaks. It appears a single product peak when the SNP is homozygous, and two product peaks with 4 bp differences will appear when it is heterozygous. By using this system, we conducted population census about allele frequencies for 13 autosomal SNP loci in Southern Liaoning Han samples, Mongolian samples in Inner Mongolia and Zhuang samples in Guangxi area, and got the allele frequencies of the 13 SNP loci in the three populations, then preliminarily discussed their genetic relationship by comparing their differences in allelic polymorphism. The results indicate that the allelic distributions of the 13 SNP loci in the three populations are polymorphic, and the difference is significant in some SNP loci (P< or =0.01). The sampling survey shows that the result is consistent with Hardy-Weinberg equilibrium, and Han population in southern Liaoning has relatively closer relationship with Mongolian in Inner Mongolia than with Zhuang population in Guangxi by origin.

[A new method for SNP typing based on allele specific PCR].

OBJECTIVE: To establish a new method of SNP typing. METHODS: Based on the principle of allele specific PCR and capillary electrophoresis technique, 11 diallelic SNP loci were selected and two forward primers with different length were designed for each SNP, with their 3' ends matched to the two alleles, respectively. An artificially mismatched base was also introduced into the third or fourth base in the 3' end area of the two forward primers in order to enhance the specificity of amplification. A common reverse primer was designed 100-300 bp away from the forward primers, and labeled with fluorescence. The PCR products were separated and analyzed by ABI Prism 310 Genetic Analyzer after all of the 11 SNPs were multiply amplified. RESULTS: A single product peak was observed while the SNP was homozygous, and two product peaks with different height were observed while the SNP was heterozygous. The length of PCR products was different with the different SNPs. According to the length of the products and the number of the product peaks, the genotypes of the 11 SNPs can simultaneously be analyzed, and the results were in accordance with the direct sequencing. CONCLUSION: Fragment length discrepant allele specific fluorescence labeled multi-PCR (FLDASFLM-PCR) is a simple, rapid and efficient new method for SNP typing.