Phlox subulata, a perennial herbaceous flower, can survive during the winter of northeast China, where the temperature can drop to −30 °C, suggesting that P. subulata is an ideal model for studying the molecular mechanisms of cold acclimation in plants. However, little is known about the gene expression profile of P. subulata under cold stress. Here, we examined changes in cold stress-related genes in P. subulata. We sequenced three cold-treated (CT) and control (CK) samples of P. subulata. After de novo assembly and quantitative assessment of the obtained reads, 99,174 unigenes were generated. Based on similarity searches with known proteins in public protein databases, 59,994 unigenes were functionally annotated. Among all differentially expressed genes (DEGs), 8302, 10,638 and 11,021 up-regulated genes and 9898, 17,876, and 12,358 down-regulated genes were identified after treatment at 4, 0, and −10 °C, respectively. Furthermore, 3417 up-regulated unigenes were expressed only in CT samples. Twenty major cold-related genes, including transcription factors, antioxidant enzymes, osmoregulation proteins, and Ca²⁺ and ABA signaling components, were identified, and their expression levels were estimated. Overall, this is the first transcriptome sequencing of this plant species under cold stress. Studies of DEGs involved in cold-related metabolic pathways may facilitate the discovery of cold-resistance genes.

In this study, to comprehensively investigate the impact of garden plants on air quality, we measured the leaves of 18 common garden plants in three different areas, namely, Suzhou industrial parks (clean air area (CAA)), Xiangcheng district parks (lightly polluted area (LPA)), and Huqiu district parks (highly polluted area (HPA)). We also measured the leaf functional traits of different life-types of plants. To explore the trade-off strategies of the leaf traits of common garden plants in response to air pollution and to assess the adaptive capacity of different life types of plants to air pollution. The results show that plants in the polluted area had higher leaf dry matter content (LDMC) and leaf nitrogen content per unit mass (N_mass), and a lower specific leaf area (SLA), maximum net photosynthetic rate per unit area (A_area), transpiration rate (Tr), stomatal conductance (Gs), and chlorophyll value (SPAD). Pearson correlation analysis showed that SLA was significantly positively correlated with N_mass, Tr, photosynthetic use efficiency (PNUE), and SPAD, and significantly negatively correlated with LDMC, while A_area was significantly positively correlated with chlorophyll value. Redundancy analysis revealed that the correlation between each leaf functional trait and atmospheric pollution factors was as follows: LDMC > N_mass > SLA > LA > A_area > Tr > PNUE > SPAD. The results suggest that different plant types have varying levels of adaptability to environmental conditions. Trees were found to be the most adaptable, followed by shrubs, herbs, and lianas. Additionally, under the stress of air pollution, herbs and lianas exhibited characteristics of “fast investment-return” on the leaf economic spectrum, meaning they were able to quickly allocate resources to maximize their return. However, trees and shrubs displayed traits of “slow investment-return”, indicating a more conservative approach to resource allocation. These results provide valuable insights into the leaf trade-off strategies of plants in Suzhou Park under air pollution stress and can guide the selection of suitable plant species in similar environments.

B. chinensis is an important medicinal plant and garden plant in China, and drought is one of the factors limiting the growth of B. chinensis, so it has become a research hotspot to investigate the physiological response mechanism of B. chinensis to drought. In this study, we investigated the physiological and biochemical response mechanisms of the root system of B. chinensis using B. chinensis seedlings as experimental materials, and root metabolomics were analyzed to investigate the response mechanisms of this plant under drought stress. The results showed that: (1) with the prolongation of drought stress, the relative water content gradually decreased, the diameter of root, the diameter of the mid-column, the thickness of the cortex, and the diameter of the xylem all showed an upward trend and then a downward trend, the root activity gradually declined, the root structure was impaired, the cortex was not arranged and ruptured. (2) With the prolongation of drought stress, the cell membrane function was impaired, the relative conductivity and malondialdehyde content of roots tended to increase, the content of osmoregulatory substances such as soluble proteins and free proline also accumulated in large quantities in the roots, and the content of hydrogen peroxide and superoxide anion gradually increased. (3) A total of 656 differential metabolites were screened in the root system of B. chinensis under drought stress. In addition, KEGG enrichment analysis revealed that the metabolic pathways involved in the differential metabolites were mainly glycerophospholipid metabolism, sphingolipid metabolism, amino acid metabolism. Among them, the differences in flavonoid biosynthesis varied greatly, suggesting that flavonoids play an important role in the response to drought stress in B. chinensis. This study reveals the defense response mechanism of B. chinensis under drought, with a view to laying a theoretical foundation for physiological and metabolic studies revealing B. chinensis response to drought stress.

Investigating the adaptive mechanisms of different plant growth forms to flooding gradients is essential for formulating scientific vegetation allocation models to support ecological restoration in aquatic–terrestrial ecotones and mitigate ecological risks associated with summer flooding. This study focused on 38 adaptable species under three flooding gradients in the Taihu Lake aquatic–terrestrial ecotone. We systematically measured leaf morphological traits, photosynthetic physiological parameters, and stoichiometric characteristics. Employing analysis of variance, correlation networks, and principal component analysis, we elucidated how flooding environments shape leaf functional trait patterns of woody and herbaceous plants. The results indicated the following. (1) With increasing flooding stress, herbaceous plants increase the leaf area (LA) and leaf dry weight (LDW), whereas woody plants decrease them, indicating that herbaceous plants demonstrate stronger adaptability than woody plants. (2) Woody plants constructed a leaf functional trait network centered on stomatal conductance (G_s), adopting a conservative resource-use strategy. In contrast, herbaceous plants formed a network centered on leaf nitrogen content (N_mass), employing a rapid resource acquisition strategy to adapt to the ecotone environment. (3) The synergistic changes in leaf traits of different growth forms were affected by flooding in distinct ways. Integrating the leaf economics spectrum and adaptive evaluation values for each species can further our understanding of plant adaptation strategies in different flooding environments and guide species selection and configuration for aquatic–terrestrial ecotone restoration.