Background: Clematisspecies are attractive ornamental plants with a variety of flower colors and patterns. Heat stress is one of the main factors restricting the growth, development, and ornamental value ofClematis.Clematis lanuginosaandClematis crassifoliaare large-flowered and evergreenClematisspecies, respectively, that show different tolerance to heat stress. We compared and analyzed the transcriptome ofC. lanuginoseandC. crassifoliaunder heat stress to determine the regulatory mechanism(s) of resistance.Results: A total of 1720 and 6178 differentially expressed genes were identified fromC. lanuginoseandC. crassifolia, respectively. The photosynthesis and oxidation–reduction processes ofC. crassifoliawere more sensitive thanC. lanuginoseunder heat stress. Glycine/serine/threonine metabolism, glyoxylic metabolism, and thiamine metabolism were important pathways in response to heat stress inC. lanuginose, and flavonoid biosynthesis, phenylalanine metabolism, and arginine/proline metabolism were the key pathways inC. crassifolia. SixsHSPs (c176964_g1, c200771_g1, c204924_g1, c199407_g2, c201522_g2, c192936_g1),POD1(c200317_g1),POD3(c210145_g2),DREB2(c182557_g1), andHSFA2(c206233_g2) may be key genes in the response to heat stress inC. lanuginoseandC. crassifolia.Conclusions: We compared important metabolic pathways and differentially expressed genes in response to heat stress betweenC. lanuginoseandC. crassifolia. The results increase our understanding of the response mechanism and candidate genes ofClematisunder heat stress. These data may contribute to the development of newClematisvarieties with greater heat tolerance.

Clematis tientaiensis is an ornamental plant with beautiful flowers that belongs to the Ranunculaceae family. C. tientaiensis is endemic to Zhejiang Province in China. Five different colours of the C. tientaiensis flower have been observed, and to explore the reason for this flower colour variation, transcriptome and metabolome sequencing analyses were conducted in this study. The results indicate that 32 metabolites participate in anthocyanin biosynthesis, and that 24 metabolites were differentially accumulated among the five different flower colours. The transcriptome sequencing results enabled the identification of 13,559 differentially expressed genes. Further analysis indicated that cyanidin-3-O-galactosidea and cyanidin-3-O-sophoroside promote anthocyanin accumulation in the flowers of C. tientaiensis, whereas the pelargonidin-3-O-galactoside plays a negative role in anthocyanin synthesis. In addition, a combined transcriptome and metabolome analysis showed that the WDR2 gene plays an important regulatory role in anthocyanin biosynthesis. The results of this study provide a basis for further research into the biosynthesis and regulation of anthocyanins in C. tientaiensis flowers.

Clematis is a perennial ornamental vine known as the “Vine Queen” for its gorgeous floral color and rich flower shape. Clematis tientaiensis, an endangered plant, is a key protected wild plant and a rare breeding parent of Clematis because of its extremely high ornamental value. Light environment is one of the important environmental factors affecting the space distribution and the size of C. tientaiensis population. One-year-old homogenous and healthy potted C. tientaiensis plants were grown under four different light intensities (T1: 1800 ± 30/0 µmol m⁻² s⁻¹; T2: 1500 ± 30/0 µmol m⁻² s⁻¹; T3: 1200 ± 30/0 µmol m⁻² s⁻¹; T4: 900 ± 30/0 µmol m⁻² s⁻¹). This study analyzed the potential adaptive mechanism of C. tientaiensis in response to irradiance by investigating the photosynthesis, rapid light curve, chloroplast ultrastructure, Rubisco activase enzyme (RAC), Rubisco enzyme, amino acids, and gene expression under four irradiance treatments. High light caused the leaves chlorosis and yellowing, reduced the net photosynthetic rate (Pn), stomatal conductance (Gs), RAC and Rubisco enzyme activity; the quantum yield of unregulated energy dissipation [Y(NO)], and increased the content of eight amino acids content. The expression of psbA, psbB, psbC, and Psb(OEC) were down-regulated with decreasing irradiance. The results showed that C. tientaiensis plants grown under T1 (1800 ± 30 µmol m⁻² s⁻¹) irradiance were in danger of absorbing more light energy than they could use for photosynthesis, while they exhibited good adaptability to the T3 (1200 ± 30 µmol m⁻² s⁻¹) irradiance, and the PSII reaction center and Rubisco and RCA enzymes could be the key points in response to high light stress, which also emphasized the importance of appropriate light management practices for promoting the growth and population expansion of C. tientaiensis.

Gladiolus is an important ornamental plant that is one of the world’s four most-grown cut flowers. Gladiolus gandavensis has only been found in the Cangnan County (Zhejiang Province) of China, which is recorded in the “Botanical”. To explore the origin of G. gandavensis, chloroplast genome sequencing was conducted. The results indicated that a total of 151,654 bp of circular DNA was obtained. The chloroplast genome of G. gandavensis has a quadripartite structure (contains a large single-copy (LSC) region (81,547 bp), a small single-copy region (SSC) (17,895 bp), and two inverted repeats (IRs) (IRa and IRb, 52,212 bp)), similar to that of other species. In addition, a total of 84 protein-coding genes, 8 rRNA-encoding genes, and 38 tRNA-encoding genes were present in the chloroplast genome. To further study the structural characteristics of the chloroplast genome in G. gandavensis, a comparative analysis of eight species of the Iridaceae family was conducted, and the results revealed higher similarity in the IR regions than in the LSC and SSC regions. In addition, 265 simple sequence repeats (SSRs) were detected in this study. The results of the phylogenetic analysis indicated that the chloroplast genome of G. gandavensis has high homology with the Crocus cartwrightianus and Crocus sativus chloroplast genomes. Genetic analysis based on the rbcl sequence among 49 Gladiolus species showed that samples 42, 49, 50, and 54 had high homology with the three samples from China (64, 65, and 66), which might be caused by chance similarity in genotypes. These results suggest that G. gandavensis may have originated from South Africa.

Clematis L., a significant genus of climbing plants within the Ranunculaceae family, boasts widespread germplasm resources distributed across temperate to tropical regions globally, with Asia preserving particularly abundant native populations. This review systematically summarizes recent advances in Clematis research: in terms of physiological characteristics, the research focuses on the evolution of plant classification, chromosomal evolutionary features revealed by karyotype analysis, and studies on genetic diversity and phylogenetic relationships based on molecular markers; in breeding methods, it summarizes the two major technical systems of sexual and asexual reproduction; regarding ornamental traits, it emphasizes the molecular mechanisms of flower color and form development, and synthesizes breakthroughs in techniques for flowering period regulation and research on the biosynthesis pathways of floral scent metabolites; in the field of stress resistance mechanisms, it thoroughly examines physiological responses and molecular adaptation mechanisms under abiotic stresses such as UV radiation, drought, high temperature, and intense light, and outlines research progress on pathogen types of major diseases; in studies of medicinal value, it highlights the material basis and mechanisms of pharmacological activities including anti-inflammatory, analgesic, and antitumor effects. Through multidimensional comprehensive analysis, this review aims to elucidate the comprehensive development potential of Clematis, providing theoretical foundations and practical guidance for germplasm resource innovation, breeding of high-ornamental-value cultivars, and stress resistance applications.