Cathaya argyrophylla is an ancient Pinaceae species endemic to China that is listed on the IUCN Red List. Although C. argyrophylla is an ectomycorrhizal plant, the relationship between its rhizospheric soil microbial community and soil properties related to the natural habitat remains unknown. High-throughput sequencing of bacterial 16S rRNA genes and fungal ITS region sequences was used to survey the C. argyrophylla soil community at four natural spatially distributed points in Hunan Province, China, and functional profiles were predicted using PICRUSt2 and FUNGuild. The dominant bacterial phyla included Proteobacteria, Acidobacteria, Actinobacteria, and Chloroflexi, and the dominant genus was Acidothermus. The dominant fungal phyla were Basidiomycota and Ascomycota, while Russula was the dominant genus. Soil properties were the main factors leading to changes in rhizosphere soil bacterial and fungal communities, with nitrogen being the main driver of changes in soil microbial communities. The metabolic capacities of the microbial communities were predicted to identify differences in their functional profiles, including amino acid transport and metabolism, energy production and conversion, and the presence of fungi, including saprotrophs and symbiotrophs. These findings illuminate the soil microbial ecology of C. argyrophylla, and provide a scientific basis for screening rhizosphere microorganisms that are suitable for vegetation restoration and reconstruction for this important threatened species.

Studying the pollen morphology of this remnant and endemic wild species of Cathaya argyrophylla can be of use for paleobiologists. During this study, 23 genotypes sampled from four natural populations in two regions of Hunan Province, China. A total of 460 pollen grains were analyzed for seven quantitative and seven qualitative traits (including five new traits). Three quantitative traits (B, P, and A) (Width of the saccus (B); Length of the polar axis (P); Length of the saccus (A)) and four qualitative traits (O-CO, B-SD, O-CSR, and B-SU) (Pollen corpus outlined in the polar distal view (O-CO); Whether the outline of two sacci was distinct or not in the polar proximal view (B-SD); Roughness degree between corpus from the polar proximal view and the sacci from the polar distal view (O-CSR); Whether the overall size of two sacci was uniform or not (B-SU)) were the diagnostic pollen features that could possible to differentiate one population and classified 23 samples into two, three, or four clusters. Furthermore, 24 environmental factors were evaluated and precipitation factors effected more on pollen morphology than geographic and temperature factors, which including annual precipitation (bio12), precipitation of wettest month and driest month (bio13, bio14), precipitation seasonality (bio15) and monthly averaged precipitation in May (05-precip). The main precipitation and temperature factors exhibited positive and negative correlation with pollen size (B and E (Equatorial diameter (E))), respectively. This article provides deeper insight into intraspecific variability of pollen grains of C. argyrophylla, which have been investigated for the first time. In addition, the insights gained from this study could assist with the seed breeding and population reproduction of the endangered C. argyrophylla tree.

Identifying useful taxonomic indicators for classifying Hibiscus syriacus L. (Malvaceae) cultivars can help address challenges in their homonymy and synonymy. Moreover, analyzing which pollen traits possibly lead to their successful fruiting can serve to guide the hybridization and breeding of H. syriacus. For the first time, this study classified 24 cultivars of H. syriacus based on 24 morphological and palynological indicators assessed for flowers, leaves, and pollen grains. These indicators were a mixture of quantitative and qualitative traits, measured to contribute to the identification and classification of H. syriacus cultivars. The results showed that the 24 H. syriacus cultivars could be classified into 2–6 clusters according to different taxonomic criteria. The leading diagnostic indicators were eight quantitative and eight qualitative traits, of which two new quantitative traits—the width of the spine base (SW) and average of the pollen grain radius and spine length (D-spine)—and five new qualitative traits—the amount of pollen surface spines (O-SA), whether the petals have the red center (B-RC), whether the pollen surface ruffles strongly (B-RS), the degree of pollen surface ruffling (O-DR), and relationship between calyx and bract (O-CB)—could be used as defining traits for H. syriacus cultivars owing to their robust contribution to the classification. The correlations between indicators for flowers, leaves, and pollen grains were explored, which revealed that the O-SA in H. syriacus was strongly tied to quantitative pollen traits. Furthermore, three qualitative morphological traits—whether the stamens are heterogeneous in terms of inner petals (B-IP), O-CB, and whether the leaf lobing is strong (B-LL)—were correlated with partial quantitative pollen traits. We also found that those H. syriacus cultivars with micro-spines or granulate on the pollen grain surface have higher fruiting rates; additionally, pollen diameter, spine length, and spine spacing might also be potential factors influencing successful breeding. The insights gained from this study could fill a key knowledge gap concerning the taxonomic criteria suitable for distinguishing H. syriacus cultivars. Our findings also provide timely information on how to understand the pollination process, especially those aspects leading to pollinator selection via pollen grain features, which could influence breeding programs and outcomes.

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Carallia brachiata (Lour.) Merr. (1919) is an important medical resource distributed across subtropical Asia. In this study, the complete chloroplast genome of C. brachiata was sequenced, revealing a total length of 162,460 bp, including four regions – a large single copy (89,814 bp), a small single copy (18,804 bp), and a pair of inverted repeats (26,921 bp each). The overall guanine + cytosine content was 35.76%. In total, 130 genes were annotated within the chloroplast genome, comprising 85 protein-coding, 37 tRNA, and 8 rRNA genes. Subsequent phylogenetic analyses revealed that C. brachiata is closely related to Carallia diplopetala .