Rhodobryum giganteum (Bryaceae, Bryophyta), a rare medicinal bryophyte, is valued for its cardiovascular therapeutic properties in traditional Chinese medicine. This study presents the first complete chloroplast genome sequence of R. giganteum, including its assembly and annotation. The circular chloroplast genome of R. giganteum is 124,315 bp in length, displaying a typical quadripartite structure with 128 genes: 83 protein-coding genes, 37 tRNAs, and 8 rRNAs. Analyses of codon usage bias, repetitive sequences, and simple sequence repeats (SSRs) revealed an A/U-ending codon preference, 96 repetitive sequences, and 385 SSRs in the R. giganteum chloroplast genome. Nucleotide diversity analysis identified 10 high mutational hotspots. Ka/Ks ratio analysis suggested potential positive selection in rpl20, rps18, petG, and psbM genes. Phylogenetic analysis of whole chloroplast genomes from 38 moss species positioned R. giganteum within Bryales, closely related to Rhodobryum laxelimbatum. This study augments the chloroplast genomic data for Bryales and provides a foundation for molecular marker development and genetic diversity analyses in medicinal bryophytes.

Salix species are widely used as vegetation filters because of their flourishing root system and fast growth rate. However, studies have yet to determine whether the root system functions in vegetable filters with mixed heavy metal (HM) pollution or whether initial cutting participates in the phytoextraction of HMs. This study aims to determine the function of the root system and initial cutting as vegetation filters in the absorption and accumulation of Cd and Cu. Thick (>1 cm in diameter) and fine (<1 cm in diameter) initial cuttings of Salix matsudana were planted in a nutrient solution with single and mixed (Cd + Cu) treatments. The roots of several initial cuttings were removed daily to eradicate rhizofiltration. Results revealed that the existence of the root system altered distribution and interaction of Cd and Cu in plant organs and enhanced tolerance and phytoextraction capacity of plants. The initial cuttings could also absorb and accumulate HMs in the early growth stages of willow without roots. Cu inhibited the plant absorption and accumulation of Cd and promoted Cd transport to shoots. Cd inhibited the Cu absorption of the root system. Our study provided essential data regarding woody species as vegetation filters of HM pollution.

(1) Background: Detailed diversity information regarding terrestrial mosses in a tropical forest ecosystem and an understanding of the drivers behind moss distribution provide crucial data for the management and conservation of forest ecosystems. Mosses are critical components of tropical forest ecosystems due to their high diversity and biomass, and they also fulfill essential ecological functions. Here, we report the first study into the relative importance of vegetation types and elevational gradient for the diversity, distribution and community structure of terrestrial moss species in southern China. (2) Methods: Five elevations spaced 200 m apart in the tropical mountain forest on the northern aspect of Tai Mo Shan were selected. The diversity, distribution, and geographical patterns of terrestrial mosses in response to altitudinal changes were examined. Differences in the biotic variables of terrestrial mosses between elevations were tested using a one-way ANOVA. Curve estimation regression models were used to describe the responses of the biotic variables to the elevation gradient. Canonical correlation analysis (CCA) was performed to identify and measure the associations among biotic variables of terrestrial mosses and abiotic environmental factors. (3) Results: Fifty-three terrestrial moss species belonging to 20 families and 31 genera were recorded along the altitudinal gradient on Tai Mo Shan. Microclimate factors including dew point and rainfall were strongly associated with the cover and thickness of the ground moss species. There were no obvious richness changes of terrestrial mosses along the elevation gradient. In total, 33 of the 51 species were tropically distributed, 14 species were found across East Asia and the tropical regions, 10 species had an East Asian pattern and 8 were temperate species. (4) Conclusions: Vegetation types significantly affect the diversity and distribution of terrestrial moss species. Although they are influenced by the East Asian and temperate climate with frequent human activities, terrestrial mosses on Tai Mo Shan are primarily tropical in nature. Forest conservation and restoration should be implemented to sustain and improve the diversity of terrestrial mosses and understory plants on Tai Mo Shan, especially at higher elevations.