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The warm-temperate and subtropical climate zones of East Asia are a hotspot of plant species richness and endemism, including a noticeable number of species-poor Tertiary relict tree genera. However, little is understood about when East Asian Tertiary relict plants diversified, how they responded demographically to past environmental change, and to what extent their current genomic composition (and adaptive capacity) might mitigate the effects of global warming. Here, we obtained genomic (RAD-SNP) data for 171 samples from two extant species of Euptelea in China (24 E. pleiosperma populations) and Japan (11 E. polyandra populations) to elucidate their divergence and demographic histories, genome-wide associations with current environmental variables, and genomic vulnerability to future climate change. Our results indicate that Late Miocene changes in climate and/or sea level promoted species divergence, whereas Late Pliocene uplifting in southwest China likely fostered lineage divergence within E. pleiosperma. Its subsequent range expansion into central/east (CE) China bears genomic signatures of climate-driven selection, yet extant CE populations are predicted to be most vulnerable to future climate change. For E. polyandra, geography was the only significant predictor of genomic variation. Our findings indicate a profound impact of Late Neogene geological and climate change on the evolutionary history of Euptelea, with much stronger signals of local adaptation left in China than in Japan. This study deepens our understanding of the complex evolutionary forces that influence the distribution of genetic variation of Tertiary relict trees, and provides insights into their susceptibility to global change and potential for adaptive responses. Our results lay the groundwork for future conservation and restoration programs for Euptelea.

Dipelta Maxim. (Caprifoliaceae) is a Tertiary relic genus endemic to China, which includes three extant species, Dipelta floribunda, Dipelta yunnanensis, and Dipelta elegans. Recent progress in the systematics and phylogeographics of Dipelta has greatly broadened our knowledge about its origin and evolution, however, conflicted phylogenetic relationships and divergence times have been reported and warrant further investigation. Here, we utilized chloroplast genomes and population‐level genomic data restriction site‐associated DNA‐single nucleotide polymorphisms (RAD‐SNPs) to evaluate the interspecific relationships, population genetic structure and demographic histories of this genus. Our results confirmed the sister relationship between D. elegans and the D. yunnanensis–D. floribunda group, but with cyto‐nuclear phylogenetic discordance observed in the latter. Coalescent simulations suggested that this discordance might be attributed to asymmetric “chloroplast capture” through introgressive hybridization between the two parapatric species. Our fossil‐calibrated plastid chronogram of Dipsacales and the coalescent modeling based on nuclear RAD‐SNPs simultaneously suggested that the three species of Dipelta diversified at the late Miocene, which may be related to the uplift of the eastern part of Qinghai–Tibet Plateau (QTP) and adjacent southwest China, and increasing Asian interior aridification since the late Miocene; while in the mid‐Pleistocene, the climatic transition and continuous uplift of the QTP, triggered allopatric speciation via geographical isolation for D. floribunda and D. yunnanensis regardless of bidirectional gene flow. Based on both plastid and nuclear genome‐scale data, our findings provide the most comprehensive and reliable phylogeny and evolutionary histories for Dipelta and enable further understanding of the origin and evolution of floristic endemisms of China. [ABSTRACT FROM AUTHOR]

Tartary buckwheat (Fagopyrum tataricum) is rich in polysaccharides that can be utilized by the gut microbiota (GM) and provide several health benefits. However, the mechanisms underlying the action of these polysaccharides remain unclear to date. In this study, Tartary buckwheat polysaccharides (TBP) were purified, and five fractions were obtained. The composition of these fractions was determined using ion chromatography. Different TBP components were investigated regarding their probiotic effect on three species of Bifidobacteria and Lactobacillus rhamnosus. In addition, the effect of TBP on GM and short‐chain fatty acids (SCFAs) was evaluated. Results showed that the probiotic effect of TBP fraction was dependent on their composition. The polysaccharides present in different fractions had specific probiotic effects. TBP‐1.0, mainly composed of fucose, glucose, and d‐galactose, exhibited the strongest proliferation effect on L. rhamnosus, while TBP‐W, rich in glucose, d‐galactose, and fructose, had the best promoting effect on Bifidobacterium longum and Bifidobacterium adolescentis growth. Furthermore, TBP‐0.2, composed of d‐galacturonic acid, d‐galactose, xylose, and arabinose, exhibited its highest impact on Bifidobacterium breve growth. The composition of GM was significantly altered by adding TBP during fecal fermentation, with an increased relative abundance of Lactococcus, Phascolarctobacterium, Bacteroidetes, and Shigella. Simultaneously, the level of SCFA was also significantly increased by TBP. Our findings indicate that Tartary buckwheat can provide specific dietary polysaccharide sources to modulate and maintain GM diversity. They provide a basis for Tartary buckwheat commercial utilization for GM modulation. [ABSTRACT FROM AUTHOR]

In this paper, a comprehensive theory for wavelength modulation laser heterodyne spectroscopy is presented. Some necessary simplifications based on the Taylor series are introduced, the general formulas employed to demodulate the first harmonic signal (1f), the second harmonic signal (2f), and higher harmonic signal (nf) are derived in details, and hence the formulas are suitable for an arbitrary intensity modulation amplitude and modulation index. The purpose of this paper: an overview of how the laser heterodyne harmonic signal depends on the experimental parameters of intensity modulation amplitude and modulation index is reported. This overview is helpful to choose these parameters for the best laser heterodyne harmonic signal because it initiated a new pathway for systematically analyzing the relationships between the experimental parameters and the laser heterodyne harmonic signal. [ABSTRACT FROM AUTHOR]

Aim: The historical circumstances promoting the transition from sexual to apomictic reproduction in dioecious plant species remain poorly understood. Here, we investigated the divergence and demographic history of Lindera glauca, a dioecious tree generally considered to be obligate sexual in China while comprising only females (apomicts) in Japan. Location: East Asia (China and Japan). Taxon: Lindera glauca (Lauraceae) Methods: Samples from 42 populations were genotyped using chloroplast DNA and nuclear microsatellite (nSSR) loci to assess genetic diversity and structure. The nSSR genotypes were also used to detect the mode of reproduction in Chinese and Japanese populations, respectively. Approximate Bayesian Computation on nSSRs and palaeoclimatic niche models provided further insights into the evolutionary and population demographic history. Results: Chinese L. glauca was found to harbour both sexual and asexual genotypes. Chinese and Japanese L. glauca underwent likely severe bottlenecks during a mid‐Pleistocene glacial period, possibly marking the split time of the island lineage from its mainland ancestor. In contrast to Chinese L. glauca, the Japanese lineage experienced a massive range contraction during the Last Glacial Maximum and postglacial expansions. Main Conclusions: While reproductive assurance plays an important role in the selection of apomixis in Chinese L. glauca, the lack of male plants in Japan likely reflects population demographic history driven by (Late) Quaternary climate change. Hence, the present study demonstrates a possible link between palaeoclimate change and the transition to exclusively apomictic reproduction in a dioecious tree. [ABSTRACT FROM AUTHOR]