Bougainvillea L. (Nyctaginaceae) is a South American native woody flowering shrub of high ornamental, economic, and medicinal value which is susceptible to cold damage. We sequenced the complete chloroplast (cp) genome of B. glabra and B. spectabilis, two morphologically similar Bougainvillea species differing in cold resistance. Both genomes showed a typical quadripartite structure consisting of one large single-copy region, one small single-copy region, and two inverted repeat regions. The cp genome size of B. glabra and B. spectabilis was 154,520 and 154,542 bp, respectively, with 131 genes, including 86 protein-coding, 37 transfer RNA, and 8 ribosomal RNA genes. In addition, the genomes contained 270 and 271 simple sequence repeats, respectively, with mononucleotide repeats being the most abundant. Eight highly variable sites (psbN, psbJ, rpoA, rpl22, psaI, trnG-UCC, ndhF, and ycf1) with high nucleotide diversity were identified as potential molecular markers. Phylogenetic analysis revealed a close relationship between B. glabra and B. spectabilis. These findings not only contribute to understanding the mechanism by which the cp genome responds to low-temperature stress in Bougainvillea and elucidating the evolutionary characteristics and phylogenetic relationships among Bougainvillea species, but also provide important evidence for the accurate identification and breeding of superior cold-tolerant Bougainvillea cultivars.

Bougainvillea plants have important ornamental and cultural value, as well as applications, for example, in improving the ecological environment, sterilization and as anti-virals in medicines, etc. Among many varieties, Bougainvillea buttiana ‘Miss Manila’ is more popular in landscape applications in southern China because of its excellent qualities. However, because of the difficulty of sexual reproduction, low rooting rate of asexual propagation cuttings and low temperature tolerance, its large-scale development is limited. For easy, quick and mass multiplication of such cultivars, tissue culture technique can be put to use. In this study, nodal segments of ‘Miss Manila’ were used as explants, and a single-factor experiment was carried out with a variety of plant growth regulators and concentrations to establish and optimize a complete tissue culture propagation system. The results showed that the best disinfestation was 75% ethanol treatment for 0.5 min + 0.1% HgCl₂ treatment for 9 min, and the survival rate was 86.83%. The best shoot initiation formula was MS + 6-BA (2.5 mg/L) + IBA (0.2 mg/L), and the induction rate was 95.14%. The best formula for shoot proliferation was MS + 6-BA (1.5 mg/L) + NAA (0.1 mg/L), and the proliferation coefficient was 3.13. The best rooting culture formula was 1/2 MS + IBA (2.0 mg/L), and the rooting rate was 81.97%. The survival rate for plantlet refining and transplanting was 93.33%. In this study, a relatively efficient regeneration system for the tissue culture and rapid propagation of Bougainvillea buttiana ‘Miss Manila’ was established to address the problems of rooting and transplanting of this variety, to benefit research on the industrialized production and regeneration systems of this variety, and to provide a reference for the tissue culture of other varieties of Bougainvillea or other woody plants.

Nymphaea hybrid, a precious water lily, is a widely-cultivated aquatic flower with high ornamental, economic, medicinal, and ecological value; it blooms recurrently and emits a strong fragrance. In the present study, in order to understand the volatile components of N. hybrid and its relationship with petals structure characteristics, the morphologies and anatomical structures of the flower petals of N. hybrid were investigated, and volatile compounds emitted from the petals were identified. Scanning and transmission electron microscopy were used to describe petal structures, and the volatile constituents were collected using headspace solid-phase microextraction (HS-SPME) fibers and analyzed using gas chromatography coupled with mass spectrometry (GC-MS). The results indicated that the density and degree of protrusion and the number of plastids and osmiophilic matrix granules in the petals play key roles in emitting the fragrance. There were distinct differences in the components and relative contents of volatile compounds among the different strains of N. hybrid. In total, 29, 34, 39, and 43 volatile compounds were detected in the cut flower petals of the blue-purple type (Nh-1), pink type (Nh-2), yellow type (Nh-3) and white type (Nh-4) of N. hybrid at the flowering stage, with total relative contents of 96.78%, 97.64%, 98.56%, and 96.15%, respectively. Analyses of these volatile components indicated that alkenes, alcohols, and alkanes were the three major types of volatile components in the flower petals of N. hybrid. The predominant volatile compounds were benzyl alcohol, pentadecane, trans-α-bergamotene, (E)-β-farnesene, and (6E,9E)-6,9-heptadecadiene, and some of these volatile compounds were terpenes, which varied among the different strains. Moreover, on the basis of hierarchical cluster analysis (HCA) and principal component analysis (PCA), the N. hybrid samples were divided into four groups: alcohols were the most important volatile compounds for Nh-4 samples; esters and aldehydes were the predominant volatiles in Nh-3 samples; and ketones and alkenes were important for Nh-2 samples. These compounds contribute to the unique flavors and aromas of the four strains of N. hybrid.

The rapid socio-economic development and urbanization in China have led to a decline in air quality. Therefore, the spatial and temporal distribution patterns of urban air pollution, as well as its formation mechanisms and influencing factors, have become important areas of research in atmospheric environment studies. This paper focuses on nine monitoring sites in Nanjing, where concentration data for six air pollutants and vegetation index data were collected from 2013 to 2021. The objective of this study is to investigate the changes in air pollutants and vegetation index over time and space, as well as their relationship with each other, and to assess the social and environmental impacts of air pollution. The findings reveal a spatial distribution pattern of air pollution in Nanjing that exhibits significant variability, with pollutant concentrations decreasing from the city center towards the surrounding areas. Notably, the main urban area has lower air quality compared to the peripheral regions. The results obtained from best-fit linear regression models and correlation heatmaps demonstrate a strong correlation (coefficient of determination, R² > 0.5) between the normalized difference vegetation index (NDVI) and pollutants such as SO₂, NO₂, PM_2.5, PM₁₀, and O₃ within a radial distance of 2 km from the air pollutant monitoring sites. These findings indicate that NDVI can be an effective indicator for assessing the distribution and concentrations of air pollutants. Negative correlations between NDVI and socio-economic indicators are observed under relatively consistent natural conditions, including climate and terrain. Therefore, the spatiotemporal distribution patterns of NDVI can provide valuable insights not only into socio-economic growth but also into the levels and locations of air pollution concentrations.

Nymphaea ‘Eldorado’, a valuable water lily, is a well-known fragrant plant in China. Studying the temporal and spatial characteristics of the floral components of this plant can provide a reference for the further development and utilization of water lily germplasm resources. In this study, headspace solid-phase microextraction (HS-SPME) combined with gas chromatography–mass spectrometry (GC-MS) was used to explore the types and relative contents of floral components at different flowering stages (S1: bud stage; S2: initial-flowering stage; S3: full-flowering stage; S4: end-flowering stage) and in different floral organs of N. ‘Elidorado’, combined with the observation of the microscopic structure of petals. A total of 60 volatile organic compounds (VOCs) were detected at different flowering stages, and there were significant differences in floral VOCs at different flowering stages and in different flower organs. The volatile compounds of N. ‘Eldorado’ can be divided into seven chemical classes,, namely, alkenes, alcohols, esters, aldehydes, ketones, alkanes, and others; the most common were alkenes and alkanes. A total of 39, 44, 47, and 42 volatile compounds were detected at S1, S2, S3, and S4. The VOCs present in high concentrations include benzaldehyde, benzyl alcohol, benzyl acetate, trans-α-bergamotene, α-curcumene, cis-α-farnesene, and so on. The types and total contents of volatiles at the full-flowering stage were higher than at other flowering stages. Comparing the VOCs in different parts of flower organs, it was found that the contents of alcohols, esters, and aldehydes were greatest in the petals, the alkenes in stamens were abundant with a relative content of up to 54.93%, and alkanes in the pistil were higher than in other parts. The types and total contents of volatiles in the stamens of N. ‘Eldorado’ were higher than those in other flower organs; they were the main part releasing fragrance. The observation of petal microstructure revealed that the size and quantity of the papillae on the epidermises of petals, the number of intracellular plastids, and the aggregates of floral components (osmophilic matrix granules) were significantly higher at the full-flowering stage than at the other flowering stages. This study suggested the main flowering stage and location at which the floral VOCs are released by N. ‘Eldorado’ and provided a reference for guiding the breeding of this water lily, exploring genetic patterns and developing related products.

Bougainvillea, a widely used ornamental plant, is mainly propagated by cuttings and tissue culture. Still, large-scale production of Bougainvillea is often difficult because of rooting issues. Therefore, based on an early establishment of the regeneration system for tissue culture in Bougainvillea by our research team, we further studied its rooting mechanism. It was observed that the morphology and anatomical structure of Bougainvillea buttiana ‘Miss Manila’ contained endogenous hormones, such as indole-3-acetic acid (IAA), abscisic acid (ABA), gibberellic acid (GA₃), and zeatin-riboside (ZR), including peroxidase (POD), polyphenol oxidase (PPO), and IAA-oxidase (IAAO) activities. Following the culture, Days 0–15 consisted of the induction and initiation stages, while Days 15–25 included the expression stages. No latent root primordium was found in the Bougainvillea plantlet, which belonged to the induced rooting type. The root primordium was derived from callus cells generated by divisions of parenchyma cells in the basic tissues. It was found that the changes in the POD, PPO, and IAAO activities were closely related to the formation of adventitious roots (AR), in which the highest rooting values occurred during the transition from the initiation stage to the expression stage, whereas the endogenous IAA and ABA contents had negative and positive correlations during the induction, initiation, and expression stages.; The values of GA₃ and ZR also peaked during the transition from the initiation to the expression stage. ZR and GA₃ were found to promote adventitious root formation, while ABA inhibited it. The IAA/ABA, ABA/ GA₃, and IAA/ZR ratios also shifted at the onset of the expression stage of AR, indicating these values were closely related to their occurrence. Overall, this study provides the basis for further research considering AR formation in Bougainvillea, and the propagation of various Bougainvillea varieties.