The complete chloroplast genome sequence of Aquilegia rockii was assembled and characterized as a resource for future genetic studies. With a total length of 162,123 bp, the chloroplast genome comprised of a large single-copy (LSC) region of 91,337 bp, a small single-copy (SSC) region of 17,376 bp, and 2 inverted repeat (IR) regions of 26,705 bp. A total of 117 unique genes, including 81 protein-coding genes, 4 ribosomal RNA genes, and 32 tRNA genes. The maximum likelihood phylogenetic analysis based on 18 cp genomes indicated that A. rockii is sister to the clade formed by Semiaquilegia adoxoides and Urophysa rockii.

Seed dormancy is an adaptive response of plants to environmental changes during long-term evolution. It plays an important role in plant survival and propagation. Acer cinnamomifolium, a plant species endemic to China, is an excellent garden and street tree species. However, dormancy and germination characteristics of A. cinnamomifolium seeds are not currently known. In the present paper, the mature seeds were used as experimental materials and we investigated the effect of temperature including alternating temperature, light, after-ripening, stratification and phytohormone on seed dormancy release and germination. After being incubated for 30 days, 0 to 10% of the seeds germinated in constant temperature (10, 15, 20, 25 and 30°C), while in alternating temperature regimes (20/10, 25/15 and 30/20°C), seed germination was < 35%. Dormancy release and germination of seeds can be increased by after-ripening, cold stratification and phytohormone treatments. We concluded that A. cinnamomifolium seeds have a non-deep physiological dormancy. Cold stratification at 4°C for 30 days and incubation thereafter at 20°C were found to be optimal for dormancy release and high seed germination.

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Many studies have found that the correlation between species richness (SR) and morphological diversity (MD) is positive, but the correlation degree of these parameters is not always consistent due to differences in categories and various ecological factors in the living environment. Based on this, related studies have revealed the good performance of using higher taxa in biodiversity research, not only by shifting the testing group scale from local communities to worldwide datasets but also by adding different taxonomic levels, such as the genus level. However, it remains unclear whether this positive correlation can also be applied to other categories or groups. Here, we evaluated the applicability of higher taxa in the biodiversity study of darkling beetles by using 3407 species (9 subfamilies, 89 tribes, and 678 genera), based on the correlation between taxa richness and morphological diversity in the tribe/genus/species. In addition, the continuous features prevalent in the tenebrionids, pronotum and elytron, were selected, and the morphological diversity of various groups was obtained by the geometric morphometric approach to quantify the morphologic information of features. This study found that genus/species richness in subfamilies Pimelinae and Stenochiinae was positively correlated with the change trend of MD, and the correlation between the MD of elytron and taxa richness gradually decreased from the tribe-level to the genus-level to the species-level test. The results confirm the stable morphology and simple function of the elytron and the applicability of tribe level in biodiversity research.

Background: Polygraphus poligraphus L., the four-eyed spruce bark beetle, belongs to the Curculionidae (Coleoptera), which mainly harms Picea asperata Mast and Pinus armandii Franch tree trunks. So far, there is no mitochondrial genome reported for P. poligraphus.Results: In this study, we sequenced and annotated the nearly complete mitogenome of P. poligraphus for the first time and predicted the secondary structures of its tRNAs. The results showed that the mitogenome of P. poligraphus was 15,302 bp (partial genome) in length with A + T content of 69.65% due to large-scale duplication. The nearly complete mitochondrial genome of P. Poligraphus contained a set of 36 genes typical of the insect mitogenome, including 13 protein-coding genes (PCGs), 2 ribosomal RNA genes (rRNAs), 21 transfer RNA genes (tRNAs) but lacked tRNA-Ile, as for the typical insect mitogenome. The results of nucleotide skew statistics showed that the AT-skews and GC-skew of P. poligraphus were positive and negative, respectively, which were similar to other Scolytinae insects. All PCGs were initiated with the standard start codon ATN. All tRNA genes had the typical cloverleaf structure, except for the trnS1, which lacked a dihydroxyuridine (DHU) arm. Furthermore, we reconstructed phylogenetic trees of P. poligraphus based on the data set of the mitogenome’s protein-coding gene sequences using the Bayesian inference (BI) method. Phylogenetic analysis indicated that the P. poligraphus mitogenome clustered with Gnathotrichus materiarius and Pityophthorus pubescens mitogenomes in a monophyletic manner. The phylogeny of these three genera of Scolytinae is presented as Polygraphus + (Gnathotrichus + Pityophthorus). Conclusions: The results presented herein will provide a reference for further molecular taxonomy, evolution and phylogenetic research of P. poligraphus. However, additional mitogenome samples are still needed to more satisfactorily resolve the phylogeny of the Scolytinae.