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Abstract Amaranthaceae s.l. is a widely distributed family consisting of over 170 genera and 2000 species. Previous molecular phylogenetic studies have shown that Amaranthaceae s.s. and traditional Chenopodiaceae form a monophyletic group (Amaranthaceae s.l.), however, the relationships within this evolutionary branch have yet to be fully resolved. In this study, we assembled the complete plastomes and full‐length ITS of 21 Amaranthaceae s.l. individuals and compared them with 38 species of Amaranthaceae s.l. Through plastome structure and sequence alignment analysis, we identified a reverse complementary region approximately 5200 bp long in the genera Atriplex and Chenopodium. Adaptive evolution analysis revealed significant positive selection in eight genes, which likely played a driving role in the evolution of Amaranthaceae s.l., as demonstrated by partitioned evolutionary analysis. Furthermore, we found that about two‐thirds of the examined species lack the ycf15 gene, potentially associated with natural selection pressures from their adapted habitats. The phylogenetic tree indicated that some genera (Chenopodium, Halogeton, and Subtr. Salsolinae) are paraphyletic lineages. Our results strongly support the clustering of Amaranthaceae s.l. with monophyletic traditional Chenopodiaceae (Clades I and II) and Amaranthaceae s.s. After a comprehensive analysis, we determined that cytonuclear conflict, gene selection by adapted habitats, and incomplete lineage sorting (ILS) events were the primary reasons for the inconsistent phylogeny of Amaranthaceae s.l. During the last glacial period, certain species within Amaranthaceae s.l. underwent adaptations to different environments and began to differentiate rapidly. Since then, these species may have experienced morphological and genetic changes distinct from those of other genera due to intense selection pressure.

The combustion process is complex and harsh, and the supersonic combustion flow field is also characterized by short duration and supersonic speed, which makes the real-time diagnostic technology for the transient environment extremely demanding. It is of great significance to realize high time-resolved accurate measurement of temperature, component concentration, and other parametric information of the combustion field to study the transient chemical reaction dynamics of the combustion field. Femtosecond CARS spectroscopy can effectively avoid the collision effect between particles in the measurement process and reduce the influence of the non-resonant background to improve the measurement accuracy and realize the time-resolved measurement on a millisecond scale. This paper introduces the development history of femtosecond CARS spectroscopy, points out its advantages and disadvantages, and looks forward to the future development trend to carry out high time-resolved measurements, establish a database of temperature changes in various complex combustion fields, and provide support for the study of engine mechanisms.

In the past 20 years, perovskite-related research has attracted wide attention. The related research into two-dimensional/quasi-two-dimensional perovskite has propelled the research of perovskite materials to a new height. To improve the properties of quasi-2D perovskite, improve the stability of materials, and achieve specific functions, using different types, volumes, and lengths of organic spacers is an essential method. In this paper, quasi-2D perovskites with EDA (ethylene diammonium), PDA (1,3-propanediammonium), and BDA (1,4-butanediammonium) (m = 2–4) as organic spacers were prepared, and the effects of different organic spacers on the 2D perovskite were investigated. The results show that the length of the organic spacer significantly impacts the perovskite’s properties. A shorter organic spacer can effectively reduce the quantum confinement and dielectric confinement in perovskite. It should be noted that if the organic spacer is too short, the stability of the quasi-2D perovskite will be greatly reduced.

Abstract Genus Comastoma (subt. Swertiinae, Gentianaceae) contains species, such as “Zangyinchen,” that are important herbs in Tibetan medicine. The phylogenetic relationship of this within Gentianaceae and the circumscriptions of its species have long been controversial with conflicting morphological and molecular data reported. Here, we used whole chloroplast genome sequences for Comastoma species and related taxa to reconstruct their phylogeny and clarify their taxonomic relationships. The results revealed that the length of all plastome sequenced varied from 149 to 151 kb and have high similarity in structure and gene content. Phylogenomic analysis showed that Comastoma is a monophyletic group, closely related to the genus Lomatogonium. The divergence time estimation showed that Gentianaceae diverged at about 21.81 Ma, while the split of Comastoma occurred at 7.70 Ma. However, the results suggested the crown age of species formation in this genus is after 4.19 Ma. Our results suggest that QTP uplift, the alternation of Quaternary glaciation and interglaciation, and monsoon changes might have acted as drivers of speciation in Comastoma.

Coal fire remains one of the main hazards of underground work. Spontaneous coal fires cause serious casualties and property losses. At present, most of the studies on coal spontaneous combustion have been conducted on working faces shorter than 200 m. However, the ultra-long working face gob of shallow buried coal seam is much larger, the distribution of its flow field is more complex, and, thus, risk of spontaneous combustion in the gob is higher. Exploring the evolution law of the gob flow field of ultra-long working face to quickly determine the range of the coal spontaneous combustion hazardous zone is of great significance to the safe production of similar mines. In this study, the gas flow field distribution in the gob of an ultra-long working face was measured by buried pipeline method and oxygen concentration was used as the index. It is found that the oxygen concentration decreases with the advance of the working face. Based on the flow field distribution, the oxidation zone of the gob was determined. Meanwhile, a three-dimensional (3D) numerical model of the working face was established, and the overlying stratum collapse and porosity evolution in the gob were simulated using the particle flow software, PFC3D discrete element software, for the porosity distribution law of the gob. The obtained porosity data were then imported into FLUENT using the custom function UDF to construct a 3D grid model. The flow field distribution in the gob was then numerically simulated for the seepage and migration law of the wind flow in the gob. The results reveal an arch-shaped wind flow field distribution with a swirl shape on the intake airway side. In the strike direction, the wind flow gradually becomes weaker with the advance of the working face. In the dip direction, the wind flow seepage range on the return airway side is obviously higher than that on the intake airway side. In the vertical direction, the wind flow range in the upper gob is larger than that in the middle and lower gob. The spontaneous combustion and oxidation zone of the gob is determined to be at 140.4–313.3 m on the intake airway side, 201.2–351.6 m in the middle of the gob, and 153.2–328.1 m on the return airway side. Finally, the residual coal distribution was superimposed onto the oxygen concentration distribution to obtain the spontaneous residual coal combustion hazardous zone in the gob.

Adenostemma lavenia is a perennial medical herb in the family Asteraceae. Here, we sequenced and analyzed the complete chloroplast genome of A. lavenia. The complete chloroplast genome size is 150,063 bp with a GC content of 37.63%. The A. lavenia chloroplast genome is a typical quadripartite structure, including a large single-copy region (LSC) of 82,017 bp and a small single-copy region (SSC) of 18,142 bp separated by a pair of inverted repeats (IRs) of 24,952 bp each. A total of 114 unique genes, including 29 tRNA genes, four rRNA genes, and 81 protein-coding genes were found in the chloroplast genome. Phylogenetic analysis revealed that A. lavenia is more closely related with Chromolaena odorata.

Ephedra species were erect, branching shrubs found in desert or arid regions worldwide as the source of ephedrine alkaloids. In this study, the complete chloroplast genome of Ephedra przewalskii and E. monosperma on the Qinghai-Tibet Plateau were sequenced, assembled, and annotated. Compared with the other four published Ephedra species, the chloroplast genomes of Ephedra species were highly conservative, with a quadripartite structure. The length of the chloroplast genome was 109,569 bp in E. przewalskii with 36.6% GC and 109,604 bp in E. monosperma with 36.6% GC. We detected 118 genes in both Ephedra species, including 73 PCGs, 37 tRNA genes, and eight rRNA genes. Among them, the ndh family genes were lost, which could be used to study the phylogeny and genetic diversity of the genus Ephedra, combined with multiple highly variable intergenic spacer (IGS) regions. Codon usage preference of Ephedra species was weak. The ratio of non-synonymous substitutions and synonymous substitutions was low, showing that the PCGs of Ephedra may be under the pressure of purifying selection. ML and BI analysis showed similar phylogenetic topologies. Ephedra species clustered together in a well-supported monophyletic clade. E. przewalskii and E. monosperma were not gathered in one clade, consistent with the classification system by Flora of China. This study reveals differences in the chloroplast genomes of Ephedra, providing valuable and abundant data for the phylogenetic analysis and species identification of Ephedra.

The complete chloroplast (cp) genome of Neopallasia pectinata was sequenced and analyzed in this study. It was 150,766 bp in length and has a typical circular structure, including a large single copy (LSC) with 82,605 bp, two inverted repeats (IRs) with 24,944 bp, and a small single copy (SSC) with 18,273 bp. The phylogenetic analysis of N. pectinata and its related taxa was conducted depended on the complete cp-genome sequences. The maximum likelihood tree indicates a close relationship between Chrysanthemum and Neopallasia. The cp-genome of N. pectinata is useful for future phylogenetic studies of Asteraceae.

Elymus dahuricus, a widely distributed perennial herb on the Qinghai-Tibetan Plateau, is highly adapted to alpine regions. In this study, we first reported the complete chloroplast (cp) genome of E. dahuricus using Illumina sequencing data. The size of the chloroplast genome is 135,096 bp, including a pair of inverted repeat regions (IRs, 20,812 bp), a large single copy region (LSC, 80,701 bp), and a small single single copy region (SSC, 12,771 bp). The chloroplast genome of E. dahuricus contained 111 genes, including 78 protein-coding genes, four ribosomal RNA genes, and 29 transfer RNA genes. Phylogenetic tree analysis suggested that E. dahuricus was closely related to E. libanoticus.

Linnaea borealis L. is a creeping shrub which grows about 5–10 cm high and is a rare clonal plant. Linnaea is a monotypic genus. Here, we release and detail the complete chloroplast genome sequences of L. borealis, whose size is 161,576 bp, containing a large single copy region (LSC) of 85,609 bp and a single copy region (SSC) of 46,694 bp which typically separates by a pair of inverted repeats (IRs) of 29,210 bp. The amount of the overall genes is 136, which includes 37 tRNA genes, eight rRNA genes, and 91 protein-coding genes. The content of the G/C in whole plastome is 61.74% while the G/C content of the LSC, SSC, and IR region are 36.58%, 38.86%, and 42.25%, respectively. The complete cp genome sequences of L. borealis will be a useful resource to the phylogenetics study in family Caprifoliaceae.

Qinghai-Tibetan Plateau (QTP) is an important biodiversity hub, which is very sensitive to climate change. Here in this study, we investigated genetic diversity and past population dynamics of Lancea tibetica (Mazaceae), an endemic herb to QTP and adjacent highlands. We sequenced chloroplast and nuclear ribosomal DNA fragments for 429 individuals, collected from 29 localities, covering their major distribution range at the QTP. A total of 19 chloroplast haplotypes and 13 nuclear genotypes in two well-differentiated lineages, corresponding to populations into two groups isolated by Tanggula and Bayangela Mountains. Meanwhile, significant phylogeographical structure was detected among sampling range of L. tibetica, and 61.50% of genetic variations was partitioned between groups. Gene flow across the whole region appears to be restricted by high mountains, suggesting a significant role of geography in the genetic differences between the two groups. Divergence time between the two lineages dated to 8.63 million years ago, which corresponded to the uplifting of QTP during the late Miocene and Pliocene. Ecological differences were found between both the lineages represent species-specific characteristics, sufficient to keep the lineages separated to a high degree. The simulated distribution from the last interglacial period to the current period showed that the distribution of L. tibetica experienced shrinkage and expansion. Climate changes during the Pleistocene glacial-interglacial cycles had a dramatic effect on L. tibetica distribution ranges. Multiple refugia of L. tibetica might have remained during the species history, to south of the Tanggula and north of Bayangela Mountains, both appeared as topological barrier and contributed to restricting gene flow between the two lineages. Together, geographic isolation and climatic factors have played a fundamental role in promoting diversification and evolution of L. tibetica.

Triosteum himalayanum is a perennial herb which is distributed in the eastern Himalayas, Hengduan Mountains, and central China. The complete chloroplast genome of T. himalayanum is studied for the first time, which is 154,579 bp in length and is divided into four regions: two inverted repeat (IRA and IRB) regions of 23,370 bp, a small single copy (SSC) region of 18,682 bp and a large single copy (LSC) region of 89,157 bp. The plastid genome contains 133 genes, including 86 protein-coding genes, 39 tRNA genes, and 8 rRNA genes. The overall CG content in the chloroplast genome of T. himalayanum is 38.38%. The phylogenetic analysis on the complete plastome sequence of T. himalayanum will help to show the intergeneric diversity of Caprifoliaceae.

Here in this work, we have sequenced the complete chloroplast genome of Comastoma falcatum. The complete chloroplast genome size of C. falcatum is 151,423 bp with 81721 bp of LSC, 25727 bp of IRa/IRb and 18248 bp of SSC. The GC contents of its chloroplast genomes are 38.26%. Their chloroplast has a total of 133 unique genes, including 88 of protein-coding genes, 8 of rRNA genes, and 37 of tRNA genes. In the maximum parsimony phylogenetic tree, C. falcatum clustered with Swertia mussotii. This sequenced chloroplast genome of C. falcatum will help to further study the phylogenetic position of Comastoma.

The taxonomic status of Parnassia has been widely discussed, which has been placed in more than five families, Parnassiaceae, Droseraceae, Saxifragaceae, and Celastraceae. Due to the lack of reliable genetic data, we sequenced and analyzed P. brevistyla chloroplast genome for future genetic study. The complete chloroplast genomes of Parnassia brevistyla was sequenced with NovaSeq 6000. The full length of P. brevistyla chloroplast genomes is 151,728 bp. A total of 114 unique genes, including 30 tRNA genes, four rRNA genes, and 80 protein-coding genes were found in the chloroplast genome. Using the whole chloroplast genome sequences alignment of 10 species from Celastraceae and Saxifragaceae, the phylogenetic relationship was built. The phylogenetic position of P. brevistyla was closely clustered with Celastraceae. The complete chloroplast genome of P. brevistyla provides utility information for further research of phylogenetic relationship and taxonomic status of Parnassia.