Phylogenetic analysis and character evolution of tribe Arethuseae (Orchidaceae) reveal a new genus Mengzia.

Delimitation of the tribe Arethuseae has varied considerably since it was first defined. The relationships within Arethuseae, particularly within the subtribe Arethusinae, remain poorly elucidated. In this study, we reconstructed the phylogeny of Arethuseae, using six plastid markers (matK, ycf1, rbcL rpoc1, rpl32-trnL and trnL-F) from 83 taxa. The ancestral state reconstruction of 11 selected morphological characters was also conducted to identify synapomorphies and assess potential evolutionary transitions. Morphological character comparision between the distinct species Bletilla foliosa and other species are conducted. Our results unequivocally supported the monophyly of Arethuseae, which included highly supported clades and a clear synapomorphy of non-trichome-like lamellae. Furthermore, B. foliosa formed a separate clade in the subtribe Arethusinae, instead of clustering with the other Bletilla species in the subtribe Coelogyninae. The morphological characters comparision further showed that the B. foliosa clade could be distinguished from other genera in Arethuseae by multiple characters, including presence of lateral inflorescence, three lamellae with trichome-like apex and four pollinia. In light of these molecular and morphological evidences, we propose Mengzia as a new genus to accommodate B. foliosa and accordingly provide descriptions of this new genus and combination.

Chloroplast Genome Analysis of Two Medicinal Coelogyne spp. (Orchidaceae) Shed Light on the Genetic Information, Comparative Genomics, and Species Identification.

Although the medicinal properties of Coelogyne spp. have been previously studied, there is little genomic information providing a valuable tool for the plant taxonomy, conservation, and utilization of this genus. This study used the next-generation MiSeq sequencing platform to characterize the chloroplast (cp) genomes of Coelogyne fimbriata and Coelogyne ovalis. The Maximum Likelihood (ML) and Bayesian (BI) methods were employed to confirm the phylogenetic position of two Coelogyne species based on the whole chloroplast genome sequences. Additionally, we developed eight new primers based on the two cp genomes' medium variable regions and evaluated the transferability to another 16 Coelogyne species. We constructed phylogenetic trees including 18 Coelogyne species and four outgroup species using the chloroplast fragments with the ML method. Our results showed that the cp genomes of C. fimbriata and C. ovalis contained a small single-copy region (18,839 and 18,851 bp, respectively) and a large single-copy region (87,606 and 87,759 bp, respectively), separated by two same-length inverted-repeat regions (26,675 bp in C. fimbriata and 26,715 bp C. ovalis, respectively). They all contained 86 protein-coding genes, 38 tRNA genes, and eight rRNA genes, revealing strong structure and gene content similarities. The phylogenetic analysis indicated a close relationship between the genera Coelogyne and Pleione. The newly developed primers revealed good transferability among the Coelogyne taxa and provided enough variable sites to distinguish C. fimbriata and C. ovalis. The two complete cp genomes and the eight new primers of Coelogyne provide new genomic data for further studies on phylogenomics, population genetics, and evolutionary history of Coelogyne taxa.

A Quantum Dot Fluorescence Sensor System Design for Hg²âº Trace Detection.

The detection of Hg²âº ions usually requires large laboratory equipment, which encounters difficulties for rapid field test in most applications. In this paper, we design a reflective sensor for trace Hg²âº analysis based on the fluorescent quenching of Quantum dots, which contains two major modules, i. e. the fluorescent sensing module and the signal processing module. The fluorescence sensing module is composed of a laser source, a light collimated system and a photo-detector, which enables the realization of the fluorescence excitation as well as its detection. The signal processing module realized the further amplification of the detected signal and hereafter the filtering of noises. Furthermore, the Hg²âº concentration will displayed on the QT interface using a Linux embedded system. The sensor system is low cost and small, which makes it available for rapid field test or portable applications. Experimental results show that the sensor has a good linear relationship for the Hg²âº concentration range from 15.0 x 10⁻9 to 1.8 x 10⁻6 mol · L⁻¹. The regression equation is V0/V = 1.309 13 + 3.37c, where c is Hg²âº concentration, and V0 is the voltage value for the blank case. In our work, the linearity is determined as 0. 989 26. The experiments exhibit that Ca²âº, Mn²âº and Pb²âº ions have small influence on the Hg²âº detection, and the interfere of other common ions can be neglected, which indicates a good selectivity of the sensor. Finally, it shows that our sensor has a rapid response time of 35 s and a good repeatability, thus it is potential for field test of trace Hg²âº.

[Quantitative detection of ethyl paraoxon based on SERS and PCA-SLR].

In the present paper, the surface-enhanced Raman spectroscopy (SERS) was used to build the model for the quantitative detection of ethyl paraoxon by the principal component analysis and segmented linear regression (PCA-SLR). Firstly, SERS in 820-1630 cm(-1) of ethyl paraoxon solution were measured and the spectra in 820-1630 cm(-1)(complete range) and 845-875 cm(-1) (characteristic range) of ethyl paraoxon solution were preprocessed by standard normal transformation (SNV), multiplicative scatter correction (MSC), the absolute values of first derivative and the second derivative respectively. Additionally, the number of dimensions of the spectra was reduced by PCA. Finally, the models were established by SLR It was found that the model developed with MSC preprocessed spectroscopy of characteristic range performed best (RMSEP: 0.33) by comparing the predictive accuracy of the different models. The result could meet with the needs in the quantitative detection of ethyl paraoxon.

[Design and development of trace Cr(VI) sensor].

Hexavalent chromium detection in medicine capsules is generally analyzed in the laboratory, it is difficult to meet the demand for field detection, and to address this problem, a sensor which can be used for on-site detection of trace amounts of hexavalent chromium was designed. It mainly includes chemically sensitive materials, optical sensing module and signal processing module, the chemical sensitive materials is to achieve the conversion of the hexavalent chromium concentration signal, the optical sensing module is to complete a stable output of the laser light source, and the signal processing module is to complete a photoelectric conversion of the weak fluorescence signal, signal amplification, and data processing and displaying. With using the indigenously developed photoelectric acquisition, conversion and signal processing system to complete the rapid detection of trace amounts of hexavalent chromium, so the miniaturization of testing instruments and on-site detection were achieved. Experimental results show that: the sensor detection results have a good linear relationship when the hexavalent chromium concentration is 10-500 microg x L(-1), the linear equation is Y = 1.542 47 x X-2.353 47, and the linearity is 0.998 62, the detection limit reaches 10 microg x L(-1), the sensor response time is about 90 seconds, 5 capsule samples were selected to do the contrast detection, and the results show that the sensor quantitative detection data is reliable, which meets trace hexavalent low cost, fast and field detection demands.

[The UV spectra of heterocyclic selenium compounds and metallic ions in ethanol solutions].

The UV spectra of heterocyclic selenium compounds and metallic ions in ethanol solutions were investigated in this paper. Heterocyclic selenium compounds included 4,5-benzopiazselenole (BP), anthra [1,2-c][1,2,5] selenadiazol-6,11-dione (AS), piazselenole (PS), 5-methyl-piazselenole (MP), 4,6-diBr-piazselenole (DBP) and 4,4-dipiazselenole (DP). Several important results were obtained: (1) The absorption wavelengthslambda of piazselenoles were bathochromic and their epsilon increased with the increased conjugative effect; (2) Sn(IV) enhanced the UV absorption of piazselenoles at higher frequencies with the ratio of nSn(IV)/nPS at 1; (3) The UV absorption of BP was obviously enhanced by Sn(IV), Cd(II), Cr(III), Sb(III), Fe(III), Fe(II) and Cu(II), while Zn(II) had little effect on the UV of BP; (4) The UV absorption of piazselenoles at higher frequencies was enhanced by Sn(IV), Cr(III) and Sb (III), and the peak of MP at 233 nm was blunt in MP-M solutions.

[The luminescence characters of heterocyclic selenium compounds and metallic ion in ethanol solutions].

We investigated the luminescence characters of the ethanol solutions containing metallic ions and heterocyclic selenium compounds with different molecular structures in this paper. Heterocyclic selenium compounds included piazselenole (PS), 4,5-benzopiazselenole (BP), 5-methyl-piazselenole (MP), and 4,4'-dipiazselenole (DP). The results were as follows: (1) When the conjugative effect of piazselenoles increased, the emission spectrum shifted to lower frequencies; (2) Sn(IV) made the DP emission wavelength shorten. Sn(IV) reduced the fluorescence of MP, but caused fluorescence enhancement for BP and DP. The fluorescence of PS couldn't be detected at normal temperature, but strong fluorescence of PS was determined when the ratio of nSn(IV)/n(PS) was 0.5; (3) Sn(IV), Cr(III), Cd(II), Cu(II) and Sb(III) caused fluorescence enhancement for BP. The fluorescence of BP was reduced when increasing the concentration of Fe(III) and Fe(II). Zn(II) had little effect on the fluorescence of BP.