Lilium lancifolium, a very important cold-resistant wild flower for lily cold resistance breeding, is widely distributed in southwestern and northeastern China. To gain a better understanding of the cold signaling pathway and the molecular metabolic reactions involved in the cold response, we performed a genome-wide transcriptional analysis using RNA-Seq. Approximately 104,703 million clean 90- bp paired-end reads were obtained from three libraries (CK 0 h, Cold-treated 2 h and 16 h at 4°C); 18,736 unigenes showed similarity to known proteins in the Swiss-Prot protein database, and 15,898, 13,705 and 1849 unigenes aligned to existing sequences in the KEGG and COG databases (comprising 25 COG categories) and formed 12 SOM clusters, respectively. Based on qRT-PCR results, we studied three signal regulation pathways —the Ca2+ and ABA independent/dependent pathways —that conduct cold signals to signal transduction genes such as LlICE and LlCDPK and transcription factor genes such as LlDREB1/CBF, LlAP2/EREBP, LlNAC1, LlR2R3-MYB and LlBZIP, which were expressed highly in bulb. LlFAD3, Llβ-amylase, LlP5CS and LlCLS responded to cold and enhanced adaptation processes that involve changes in the expression of transcripts related to cellular osmoprotectants and carbohydrate metabolism during cold stress. Our study of differentially expressed genes involved in cold-related metabolic pathways and transcription factors facilitated the discovery of cold-resistance genes and the cold signal transcriptional networks, and identified potential key components in the regulation of the cold response in L lancifolium, which will be most beneficial for further research and in-depth exploration of cold-resistance breeding candidate genes in lily.

Urban green space is considered to reduce the concentration of forcing factors of climate change such as the carbon dioxide in the atmosphere. Promoting carbon sequestration efficiency within a limited urban green space has become a practical challenge that must be faced in urban sustainability. This study proposed three design models and a list of high carbon sequestration plants. Based on the research on the distribution and change in carbon sequestration in urban green spaces, combined with field surveys and remote sensing images, this study analyzed the main factors affecting carbon sequestration. The results showed that the carbon sequestration capacity in urban green space tends to decrease gradually along with the change in forest structure in a time series of the years 2000, 2007, 2014, and 2019, and this trend was mainly related to the characteristic factors of plant communities in urban green spaces: the carbon sequestration of plants was significantly positively correlated with DBH (diameter at breast height) and community density; positively correlated with hierarchical structure. In addition, we put forward a list of plants with high carbon sequestration, including Styphnolobium japonicum, Salix babylonica, Pittosporum tobira, Spiraea salicifolia, and Iris pseudacorus, proposed three planting design models for different green spaces and habitats to improve the efficiency of carbon sequestration in urban green spaces, and established the community structure models of high carbon-fixing plants which can be directly applied to practical projects. It also explored the sustainable design approach of ecological processes in low-carbon cities.