Summary: The hyperaccumulating ecotype of Sedum alfredii Hance is a cadmium (Cd)/zinc/lead co‐hyperaccumulating species of Crassulaceae. It is a promising phytoremediation candidate accumulating substantial heavy metal ions without obvious signs of poisoning. However, few studies have focused on the regulatory roles of miRNAs and their targets in the hyperaccumulating ecotype of S. alfredii. Here, we combined analyses of the transcriptomics, sRNAs and the degradome to generate a comprehensive resource focused on identifying key regulatory miRNA‐target circuits under Cd stress. A total of 87 721 unigenes and 356 miRNAs were identified by deep sequencing, and 79 miRNAs were differentially expressed under Cd stress. Furthermore, 754 target genes of 194 miRNAs were validated by degradome sequencing. A gene ontology (GO) enrichment analysis of differential miRNA targets revealed that auxin, redox‐related secondary metabolism and metal transport pathways responded to Cd stress. An integrated analysis uncovered 39 pairs of miRNA targets that displayed negatively correlated expression profiles. Ten miRNA‐target pairs also exhibited negative correlations according to a real‐time quantitative PCR analysis. Moreover, a coexpression regulatory network was constructed based on profiles of differentially expressed genes. Two hub genes, ARF4 (auxin response factor 4) and AAP3 (amino acid permease 3), which might play central roles in the regulation of Cd‐responsive genes, were uncovered. These results suggest that comprehensive analyses of the transcriptomics, sRNAs and the degradome provided a useful platform for investigating Cd hyperaccumulation in S. alfredii, and may provide new insights into the genetic engineering of phytoremediation.

GFAP is a gene functional annotation tool for myriad plant studies.

Understanding the adaptability of Chionanthus retusus Lindl. et Paxt. to extreme water conditions will help in exploring the potential application of this species in barren mountains. Three-year-old Chionanthus retusus seedlings were used in a greenhouse pot experiment that analyzed the effect of different moisture gradients on growth, photosynthetic and fluorescence characteristics, protective enzyme system, osmotic substance regulation and cell membrane damage. The results indicated that C. retusus can effectively grow at a relative soil water content of 44.6% and above and can maintain growth for 20 days under flooded conditions. Under drought stress, net photosynthesis rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), and intercellular carbon dioxide concentration (Ci) all showed a trend of gradual decrease. The trend of change was similar under waterlogging conditions. The maximal quantum yield of PSII photochemistry (F_v/F_m), actual photochemical efficiency of PSII (Φ_PSII), photochemical quenching coefficient (q^P), and electron transport rate (ETR) all decreased as drought deepened. Malondialdehyde (MDA) content decreased first and then increased. However, superoxide dismutase (SOD) activity content, peroxidase (POD) activity content, and proline (Pro) activity content showed a trend of increasing and then decreasing. C. retusus had good adaptability in the slight drought treatment group and flooded treatment group but showed intolerance in the high drought group, which could still last for approximately 21 days. C. retusus was found to have a strong adaptability to water stress and can be used as an afforestation tree in barren mountains.