Search Results (16)

This study aimed to evaluate the rooting success of Loropetalum chinense var. rubrum Yieh cuttings in three different rooting media: 100% peat, 100% perlite, and a 50% peat–50% perlite mixture. Additionally, three concentrations of Indole Butyric Acid (IBA)—1000 ppm, 3000 ppm, and 6000 ppm—were tested, along with a control group consisting of non-hormone-treated cuttings. The chlorophyll content of the leaves was measured in µmol/m², and its relationship with rooting success was examined. Measurements were conducted every 15 days over a 120-day period. The collected data were analyzed using both an artificial neural network (ANN) and SPSS 29.0.2 statistical software. Results indicated that perlite medium yielded the highest rooting rate and chlorophyll concentration, whereas the peat medium performed the poorest. While 1000 ppm IBA led to the greatest improvement in rooting rate, 6000 ppm resulted in the highest chlorophyll concentration. The highest chlorophyll levels were observed during measurement periods M7, M8, and M9. Analyses of peat moisture and pH indicated that the physicochemical properties of the rooting media significantly influenced cutting development. This study aims to support the identification of optimal propagation methods for this species and to contribute to the literature by developing an ANN model based on the measured parameters. Full article

Loropetalum chinense is a significant small tree and ornamental shrub known for its colorful foliage and is widely used in landscaping in tropical and subtropical regions. This study aimed to establish an efficient, tissue culture-independent genetic transformation system for L. chinense. Cuttings from two varieties, ‘Xiangnong Xiangyun’ and ‘Hei Zhenzhu’, were infected with different strains of Agrobacterium rhizogenes. The results showed that the K599 strain significantly induced hairy roots in both varieties, with ‘Xiangnong Xiangyun’ demonstrating a higher survival rate (60%), rooting rate (51.66%), and hairy root induction efficiency (45%) compared to ‘Hei Zhenzhu’. Based on these findings, ‘Xiangnong Xiangyun’ and the K599 strain were selected for further optimization through an orthogonal L9 (3³) experiment, which focused on optimizing the infection solution composition, bacterial concentration, and infection duration, Finally, the genetic transformation system established at the beginning of the experiment was validated on ‘Xiangnong Xiangyun’ plants using the pre-screening LcDREB-43 gene of our group. Among these factors, infection duration was identified as the most influential for improving transformation efficiency. The optimal conditions were determined as an infection solution containing MES solution, a bacterial concentration of OD₆₀₀ = 0.8, and a 15 min infection duration. Under these optimized conditions, the survival rate, rooting rate, induction efficiency, and transformation efficiency reached 86.67%, 70%, 61.67%, and 43.33%, respectively. Furthermore, the transgenic plants with LcDREB-43 overexpression and pCAMBIA1305-GFP were obtained through the established transformation system, the authenticity of the system was proved, and the production application was carried out through phenotypic observation, molecular identification, and auxiliary verification of physiological indicators. Full article

Leaf functional traits are an important part of plant adaptive strategies and respond differently to different environments, but our understanding of how plants adapt to highly complex urban environments through coordinated changes in leaf functional traits is limited. In order to deeply explore the effects of different urban environments on the leaf functional traits of landscape plants, this study focused on ten common landscape plants in Nanjing, specifically, Euonymus japonicus, Pittosporum tobira, Loropetalum chinense, Photinia × fraseri, Acer palmatum, Euonymus japonicus ‘Aurea-marginatus’, Platanus acerifolia, Camphora officinarum, Ginkgo biloba, and Lagerstroemia indica. The study employed one-way analysis of variance (ANOVA), two-way ANOVA, principal component analysis (PCA), and membership function comprehensive evaluation to explore the responses of green space plants to the environments of urban park green spaces (PAR), urban community green spaces (NL), and urban road green spaces (CR) and to analyze the impact of the trade-off strategies of plants in different green space environments based on leaf functional traits. The results showed that plant leaf functional traits and their adaptive strategies varied in different urban environments in Nanjing. The contents of LDMC, MDA, POD, and CAT in the ten plant species followed the order CR > NL > PAR, and SLA, SOD, SS, and total chlorophyll showed trends of PAR > NL > CR. The microstructures of the leaves of the ten plant species, such as SA, TUE, and TS, were evident in the expression of adaptive adjustments to the different green space environments. The principal component analysis and the comprehensive evaluation of the affiliation function of the indicators of the ten plant species revealed that the adaptability of the ten green space plants to the complex urban environment was as follows: Euonymus japonicus ‘Aurea-marginatus’ > Lagerstroemia indica > Acer palmatum > Photinia × fraseri > Platanus acerifolia> Camphora officinarum > Loropetalum chinense > Ginkgo biloba > Euonymus japonicus > Pittosporum tobira. The results of the study will help to further understand the layout, application, and maintenance of landscape plants in the context of urbanization and provide support for related theories. Full article

Due to the frequent occurrence of forest fires worldwide, which cause severe economic losses and casualties, it is essential to explore the mechanisms of forest fires. In this study, seven common broadleaf plant species from southern China were selected to observe their microscopic structural parameters. The combustion performance parameters of the leaves of these seven species were measured using a cone calorimeter, and the relationship between the microscopic structure and combustion performance was analyzed. Additionally, factor analysis was used to study the combustion intensity factor (F1), fire resistance intensity factor (F2), and the comprehensive fire risk degree (F) of the leaves of the seven plant species. Finally, regression analysis was performed between the microscopic structural parameters and the comprehensive fire risk factor. The results show the following: (1) The ratio of spongy mesophyll to palisade cells (S/P) affects the combustion performance of plant leaves. (2) The ranking of the comprehensive fire risk factor for the leaves of the seven plant species is as follows: Osmanthus fragrans var. semperflorens (OFS) > Cinnamomum camphora (CC) > Loropetalum chinense (R. Br.) Oliv. (LC) > Pterocarya stenoptera C. DC. (PS) > Loropetalum chinense var. rubrum (LCVR) > Photinia beauverdiana C. K Schneid. (PB) > Styphnolobium japonicum (L.) Schott (SJ). (3) There is a strong exponential relationship between the comprehensive fire risk factor and the microscopic structural parameters. This study is beneficial for selecting fire-resistant tree species and monitoring species with higher comprehensive fire risk. Full article

This study aimed to investigate the association between the plant community structure, leaf surface microstructure, nutrient element content, and the dust-retention capacity of garden plants in urban road green spaces. The plant community located along Ying Tian Street in Nanjing City was selected as the focal point of the investigation. Random sampling was performed on the urban road green spaces, determining the amount of dust trapped in plant leaves. Subsequently, the microstructure of the leaf surface was observed, and the content of nutrient elements in the plant leaves was determined. The study also entailed an analysis of the interrelationships between the leaf surface microstructure, plant nutrient element content, and the dust-retention ability of the plants. The findings of this study revealed notable variations in the dust-retention capacity of garden plants and the community structure observed along Ying Tian Street. Among the tree species, Cedrus deodara and Ginkgo biloba exhibited a remarkable dust-retention ability per unit leaf area. Among the shrub species, Abelia × grandiflora and Loropetalum chinense displayed a strong dust-retention capacity per unit leaf area. Similarly, Ophiopogon japonicus and Cynodon dactylon exhibited a robust dust-retention ability per unit leaf area among the herbaceous plants. Furthermore, the dust-retention ability of the plants exhibited a strong positive correlation with the dimensions of leaf stomata, specifically the length and width, while displaying a moderate positive correlation with the width of grooves on the upper and lower surfaces of the leaves. Conversely, the thickness of the leaves did not exhibit a significant correlation. Additionally, the nitrogen content of the leaves exerted a significant influence on the dust-retention ability of the plants (p < 0.05), although the phosphorus and potassium content factors did not exhibit a significant influence (p > 0.05). Based on the findings, it is recommended to prioritize the utilization of plants with robust dust-retention abilities, such as C. deodara, A. grandiflora, O. japonicus, and C. dactylon, and implement a mixed planting approach encompassing a combination of trees, shrubs, and herbaceous plants within urban road green spaces. Full article

The basic helix–loop–helix (bHLH) transcription factor family is the second-largest transcription factor family in plants. Members of this family are involved in the processes of growth and development, secondary metabolic biosynthesis, signal transduction, and plant resistance. Loropetalum chinense var. rubrum is a critical woody plant with higher ornamental and economic values, which has been used as ornamental architecture and traditional Chinese herbal medicine plants. However, the bHLH transcription factors in Loropetalum chinense var. rubrum (L. chinense var. rubrum) have not yet been systematically demonstrated, and their role in the biosynthesis of anthocyanin is still unclear. Here, we identified 165 potential LcbHLHs genes by using two methods, and they were unequally distributed on chromosomes 1 to 12 of the genome of L. chinense var. rubrum. Based on an evolutionary comparison with proteins from Arabidopsis and Oryza sativa, these bHLH proteins were categorized into 21 subfamilies. Most LcbHLHs in a particular subfamily had similar gene structures and conserved motifs. The Gene Ontology annotation and Cis-elements predicted that LcbHLHs had many molecular functions and were involved in processes of plant growth, including the biosynthesis of flavonoids and anthocyanins. Transcriptomic analysis revealed different expression patterns among different tissues and cultivars of L. chinense var. rubrum. Many LcbHLHs were expressed in the leaves, and only a few genes were highly expressed in the flowers. Six LcbHLHs candidate genes were identified by bioinformatics analysis and expression analysis. Further Real-time quantitative PCR analysis and protein interaction network analysis showed that LcbHLH156, which is one of the candidate proteins belonging to the IIIf subfamily, could interact with proteins related to anthocyanin synthesis. Therefore, LcbHLH156 was transiently expressed in L. chinense var. rubrum to verify its function in regulating anthocyanin synthesis. Compared with the control group, red pigment accumulation appeared at the wound after injection, and the total anthocyanin content increased at the wound of leaves. These results lay a foundation for the research of the regulation mechanism of leaf colors in L. chinense var. rubrum and also provide a basis for the function of the LcbHLH family. Full article

Light quality is a vital environmental signal used to trigger growth and to develop structural differentiation in plants, and it influences morphological, physiological, and biochemical metabolites. In previous studies, different light qualities were found to regulate the synthesis of anthocyanin. However, the mechanism of the synthesis and accumulation of anthocyanins in leaves in response to light quality remains unclear. In this study, the Loropetalum chinense var. rubrum “Xiangnong Fendai” plant was treated with white light (WL), blue light (BL), ultraviolet-A light (UL), and blue light plus ultraviolet-A light (BL + UL), respectively. Under BL, the leaves were described as increasing in redness from “olive green” to “reddish-brown”. The chlorophyll, carotenoid, anthocyanin, and total flavonoid content were significantly higher at 7 d than at 0 d. In addition, BL treatment also significantly increased the accumulation of soluble sugar and soluble protein. In contrast to BL, ultraviolet-A light increased the malondialdehyde (MDA) content and the activities of three antioxidant enzymes in the leaves, including catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD), in varying degrees over time. Moreover, we also found that the CRY-like gene, HY5-like gene, BBX-like gene, MYB-like gene, CHS-like gene, DFR-like gene, ANS-like gene, and UFGT-like gene were significantly upregulated. Furthermore, the SOD-like, POD-like, and CAT-like gene expressions related to antioxidase synthesis were found under ultraviolet-A light conditions. In summary, BL is more conducive to reddening the leaves of “Xiangnong Fendai” and will not lead to excessive photooxidation. This provides an effective ecological strategy for light-induced leaf-color changes, thereby promoting the ornamental and economic value of L. chinense var. rubrum. Full article

The WRKY gene family plays important roles in plant growth and development, as well as in the responses to biotic and abiotic stresses. Loropetalum chinense var. rubrum has high ornamental and medicinal value. However, few WRKY genes have been reported in this plant, and their functions remain unknown. To explore the roles that the WRKY genes play in L. chinense var. rubrum, we identified and characterized 79 LcWRKYs through BLAST homology analysis and renamed them (as LcWRKY1–79) based on their distribution on the chromosomes of L. chinense var. rubrum. In this way, according to their structural characteristics and phylogenetic analysis, they were divided into three groups containing 16 (Group I), 52 (Group II), and 11 (Group III) WRKYs, respectively. LcWRKYs in the same group have similar motifs and gene structures; for instance, Motifs 1, 2, 3, 4, and 10 constitute the WRKY domain and zinc-finger structure. The LcWRKY promoter region contains light response elements (ACE, G-box), stress response elements (TC-rich repeats), hormone response elements (TATC-box, TCA-element), and MYB binding sites (MBS, MBSI). Synteny analysis of LcWRKYs allowed us to establish orthologous relationships among the WRKY gene families of Arabidopsis thaliana, Oryza sativa, Solanum lycopersicum L., Vitis vinifera L., Oryza sativa L., and Zea mays L.; furthermore, analysis of the transcriptomes of mature leaves and flowers from different cultivars demonstrated the cultivar-specific LcWRKY gene expression. The expression levels of certain LcWRKY genes also presented responsive changes from young to mature leaves, based on an analysis of the transcriptome in leaves at different developmental stages. White light treatment led to a significant decrease in the expression of LcWRKY6, 18, 24, 34, 36, 44, 48, 61, 62, and 77 and a significant increase in the expression of LcWRKY41, blue light treatment led to a significant decrease in the expression of LcWRKY18, 34, 50, and 77 and a significant increase in the expression of LcWRKY36 and 48. These results enable a better understanding of LcWRKYs, facilitating the further exploration of their genetic functions and the molecular breeding of L. chinense var. rubrum. Full article

The Loropetalum chinense and Loropetalum chinense var. rubrum are typical as well as traditional ornamental and Chinese herbal medicines in Asia; however, more information is needed on the mechanisms underlying their flower coloring. Here, we profiled the flavonoid metabolome and carried out full-length sequencing in addition to transcriptome analyses to investigate the flavonoid biosynthesis and global transcriptome changes among different petal coloring cultivars of L. chinense and L. chinense var. rubrum. The total anthocyanins in addition to the RHSCC values and CIE 1976 L*a*b* values of petals were highly consistent with petal color. Moreover, a total of 207 flavonoid components were identified. Of these, 13 flavonoid compounds were considered significantly different expression compounds highly consistent with color information in the 4 samples. Meanwhile, the first reference full-length transcriptome of L. chinense var. rubrum was built, which had 171,783 high-quality nonredundant transcripts with correcting with next-generation sequencing (NGS). Among them, 52,851 transcripts were annotated in the seven databases of NR, KOG, GO, NT, Pfam, Swiss-Port, and KEGG. Combined with NGS analyses, the DETs involved in flavonoids and anthocyanins contributed greatest to the flower coloring. Additionally, the different expressions of eight LcDFRs and four LcANS genes were positively correlated with flavonoid biosynthesis, and the four LcBZ1 as well as one Lc3Mat1 were positively correlated with the content of seven anthocyanins revealed by coupling with metabolomics and transcriptomics analyses. Together, these results were used to mine candidate genes by analyzing flower coloring changes at comprehensive metabolic and transcriptomic levels in L. chinense and L. chinense var. rubrum. Full article

The development of phytoremediation by garden plants is an effective way to deal with the dilemma of municipal sewage sludge disposal. In this study, two ornamental plants were used as phytoremediation plants to rehabilitate heavy-metal-contaminated municipal sewage sludge in field experiments, and the role of exogenous phytohormone IAA was also tested. Ornamental plants Loropetalum chinense var. rubrum (L. rubrum) and Rhododendron pulchrum (R. pulchrum) adapted well to the artificial soil made of municipal sewage sludge, and the concentrations of Cu, Zn, Pb, and Ni were decreased by 7.29, 261, 20.2, and 11.9 mg kg⁻¹, respectively, in the soil planted with L. rubrum, and 7.60, 308, 50.1, and 17.7 mg kg⁻¹, respectively, in the soil planted with R. pulchrum, accounted for 11–37% of the total amounts and reached significant levels (p < 0.05), except Cd. The concentration of Pb in all parts of the two ornamental plants was increased, as well as most heavy metals in L. rubrum root. As a result, three months after transplant, the phyto-extraction amounts in L. rubrum were 397, 10.9, and 1330 μg for Ni, Cd, and Pb, respectively, increased by 233% to 279%. The phyto-extraction amount in R. pulchrum were 1510, 250, and 237 μg for Zn, Pb, and Cu, respectively, increased by 143% to 193%. These results indicated a potential to remediate heavy metals of the two ornamental plants, especially L. rubrum. The results of correlation analysis implied that the interaction of heavy metals in the plant itself played an important role in the uptake of heavy metals. This seemed to explain why applying IAA in the experiment had little effect on plant growth and phytoremediation of heavy metals. This study provided a green and feasible idea for the proper disposal of municipal sewage sludge. Full article

The Apulia (southern Italy) ornamental sector has been facing regulatory obligations and trade limitations due to a Xylella fastidiosa (Xf) outbreak since 2013. Alternative options to encounter these constraints include the implementation of novel and sustainable ornamental production (NSM) practices. In this context, the purpose of this study is to assess simultaneously the environmental implications and economic viability of these options versus the conventional production options (CMs) among eight ornamental species (Abelia grandiflora, Bougainvillea cv Don Mario, Lantana camara cv Bandana rosa, Jasminum officinalis, Photinia fraseri cv Red Robin, Loropetalum chinense cv Black Pearl, Trachelospermum jasminoides, Viburnum lucidum). Life cycle assessment (LCA) and cost–benefit analysis (CBA) were used for this purpose. LCA revealed that NSM induced relatively less environmental impacts at the nursery level towards agricultural land occupation, climate change, fossil depletion, and water depletion. CBA showed that NSM increases moderately nursery business profitability in an economic sustainable way. An overall annual average gross margin of about EUR 192/1000 plants can be generated using NSM over the CM model. In general, this research provides a useful decision-support, helping nursery growers under the pressure of the threat of quarantine pests such as Xf to adopt NSM practices, which could be useful to produce ornamental and landscape plants with high sanitary quality. Full article

Loropetalum chinense var. rubrum is a common landscape plant. Because of the preference for the ‘red leaf’ trait, the ‘flower color’ trait was ignored in breeding, and the genetic diversity of L. chinense var. rubrum was replaced by a few genotypes. Therefore, the potential value of flower color traits was affected, and the genetic diversity was not fully exploited. In this study, we utilized a cultivar with mosaic-colored flowers and leaves and observed 15 phenotypic traits in its flower organs and its progeny, as well as a total of 60 different flower color materials. We analyzed the variation characteristics and diversity of flower colors, and qualitatively described and preliminarily classified flower colors using the ISCC-NBS and CIELab systems to explore the correlation with the flower color phenotype from the distribution and content of anthocyanins. The phenotypic diversity of the flower organs was enriched, and genetic differences in flower color were significant for the L.chinense var. rubrum, with most of the 15 phenotypic traits showing significant positive correlations, and the most critical phenotypes are sepal, petal and nectary color, as well as petal length. According to the CIELab color system and anthocyanin content and distribution characteristics, it is considered more accurate and convenient to classify the color phenotypes of L. chinense var. rubrum flowers into five categories. In this study, for the first time, the flower organ phenotype of L. chinense var. rubrum has been systematically analyzed, and it is explored as a reference method for breeding new cultivars of a diverse range of colors in L. chinense var. rubrum. Full article

Leaves from four common tree species in Chinese mountain forests, namely, Symplocos setchuensis Brand, Tarenna mollissima, Loropetalum chinense, and Castanopsis sclerophylla were studied to assess their ignitability. The microstructure of each sample was determined to investigate its effect on combustion performance. Differential thermogravimetric analysis–differential scanning calorimetry (DTA–DSC) was performed to characterize thermal decomposition processes and relate them to flammability and fire resistance. In addition, pyrolysis reaction kinetic models were built, and fitting results were obtained in order to estimate the ignitability of the different abovementioned tree types. In this paper, the activation energy of the lignin decomposition stage was used to determine the fire hazard and ignitability. Regression analysis and correlation tests of microstructural parameters were performed. The results indicated that Castanopsis sclerophylla possessed the greatest fire hazard, followed by Loropetalum chinense, Tarenna mollissima, and Symplocos setchuensis Brand. The results of this study can provide a practical basis for the selection of fire-resistant tree species and forest belts. Full article

The auto exhaust and dust derived from increased traffic volumes have led to an increasing level of atmospheric particulates in urban areas, which have become a primary pollutant of ambient air in urban zones. Roadside plants can effectively retain atmospheric particulates and clean the urban air via foliar capture of road dust. Five common roadside plants in Hangzhou were selected to evaluate their capacity for the retention of particulate matter (PM) and the accumulation of metals. The results showed that the PM retention capacity of the different plants varied greatly, as was the case with Loropetalum chinense var. rubrum Yieh, Osmanthus fragrans (Thunb.) Loureiro, Pittosporum tobira (Thunb.) Ait, Photinia × fraseri Dress and Cinnamomum camphora (L.) Presl. In addition, the amounts of particles retained by the plants varied among seasons, with the highest retention in winter (12.19 g·m⁻²) and the lowest retention in spring (6.89 g·m⁻²). The solids on the leaf surface were mainly irregular particles, such as mineral fragments, soot aggregates, and fly ash particles. Meanwhile, these plant species can effectively accumulate heavy metals that attached to the particles. The leaves of the five tree species had the highest amounts of copper (Cu) and the lowest amounts of cadmium (Cd). Among species, L. chinense and P. tobira had the strongest comprehensive capacity to adsorb particulate matter and heavy metals. The results shed light on the rational selection of road plants, both as ornaments and to purify air via dust suppression in subtropical zones. Full article

The potential of urban greening plants to capture particulate matter (PM) from the ambient atmosphere is contingent on interactions between the level of pollution and leaf surfaces. For this study, thirteen plant species were investigated to quantify their capacity of PM accumulation under three atmospheric environments, that is, industrial, traffic and university campus (control), in Kunming City (Southwest China). The sampled sites represented different pollution levels (that is, high pollution, slight pollution and clean air, respectively). The plant species differed in their accumulation of PM by six- to eight-fold across the three sites. Magnolia grandiflora was the most efficient evergreen tree species, whereas Platanus acerifolia had the highest capture of PM among deciduous trees. The accumulation capacity of the same species varied with the degree of pollution. For example, Osmanthus fragrans, Loropetalum chinense and Cinnamomum japonicum were highly efficient for the capture of PM in the traffic and university campus areas; however, they exhibited medium accumulation in the industrial area. Prunus majestica demonstrated an intermediate accumulation capacity in the industrial area, but was low in the traffic and university campus areas. The capturing capacity of the same genus was also different among the different levels of pollution. For example, C. japonicum had a 2.9–4.2-times higher PM accumulation than did C. camphora across the three sites. There were significant differences in leaf surface area, stomata density/length, guard cell area, and trichome density/length among these species. The species-specific efficacy of PM capture was primarily contributed to by leaf size and surface roughness, stomata density, and trichome length. In particular, hairy-leaf leaves with medium stomatal density exhibited higher PM capture. Therefore, leaf micromorphology, leaf size and longevity appeared to be significant predictive factors for the accumulation of PM, which may aid in the selection of greening plant species for the remediation of pollutants in urban areas. Full article