The study aimed to define the floral colour of Phalaenopsis precisely and establish a classification system of Phalaenopsis based on floral colour phenotypes. In this study, the floral colour phenotypes of 146 Phalaenopsis germplasm resources were determined using colourimeter and RHSCC, and the floral colours of each Phalaenopsis were named by cluster analysis and combined with ISCC-NBS system, and the quantitative classification was studied. The results showed that the colour of Phalaenopsis petals and sepals did not differ much, and the lip petals were darker and more colourful than petals and sepals. The classification results based on cluster analysis of L^*, a^* and b^* of petals could not fully characterize the classification of Phalaenopsis flower colours. The ISCC-NBS system divided Phalaenopsis flower colour into yellow, brown, red, violet, pink, purple and white groups. Each group had a preferable correspondence with L^*, a^* and b^* parameters of the CIE Lab system, which could realize the quantitative description of different Phalaenopsis flower colour and the colour group classification was reasonable. Phalaenopsis were rich and colourful, and there were significant differences between different colour groups of Phalaenopsis, but lacking blue-green colour. Overall the brightness and colouration of Phalaenopsis were negatively correlated, and could be divided into two groups, the first type containing yellow, brown, violet, pink, purple and white groups, the second type containing red colour groups.

Six nuclear extracts and three leaves of different development stage were screened to establish the flow cytometry (FCM) method for determining the genomic size of Piper L. and Cucumis sativus L. was used as the DNA reference standard. Result showed that the modified nuclear extract and inverted leaf were suitable for the flow cytometry of Piper L. The genome size of cultivated varieties, including Kuching, Aman and EMAS, ranged from 667.94 to 719.32 Mb, and Reyin1, microphylla variety from Cambodia, Panniyur-1 and 73F5 ranged from 759.69 to 785.38 Mb. Therefore, the genome size was significantly different among cultivated varieties. Furthermore, it is speculated that the chromosome numbers of P. wallichii and P. hancei, with genome size larger than 900 Mb, should be larger than 52 with a multiple of 13, and the number of chromosomes of germplasm, with genome size ranged from 600 to 800 Mb, may be 52. The hybrid not only had similar phenotypes to cultivated varieties and P. flaviflorum, but also had an average genome size of cultivated varieties and P. flaviflorum. Therefore, it is speculated that the hybrid may be the hybrid offspring of cultivated varieties and P. flaviflorum. This study would provide a method for the determination of the genome size of Piper L. germplasm, and provide a technical basis for the study of Piper L. germplasm evaluation and distant hybridization.

In order to understand the diversity and distribution characteristics of orchids in Gexigou National Nature Reserve in Sichuan province, a systematic survey was conducted using the line transect combined with sample sampling method from 2020 to 2021. A total length of 95 km including 17 lines were set up, covering various function, habitat and elevation of the reserve. 34 species of Orchidaceae in 20 genera were investigated. Among them, 10 were rare and endangered species, five were wild species under second-class national protection; and two (Liparis brunnea and L. rostrate) were new record species in Sichuan province. Most of them were mainly in terrestrial orchid of life type and absolutely dominant in north temperate zone of geographical. A total of 6703 orchids of 34 species were investigated and distributed in 290 sites. Galearis spathulata and Neottia megalochila were the most and least abundant species respectively, and Epipactis helleborine was the most widely-distributed. Among them, the height of Cypripedium guttatum showed a significant negative correlation with elevation, while there was a slightly correlation in other species. Most of Orchidaceae genera were distributed in 3100-3300 m, followed by 2900-3100 m, while the maximum number of individuals were distributed in 3900-4100 m. The number of Cephalanthera longifolia was positively correlated with slope significantly, the number of Galearis spathulata was positively correlated with elevation significantly, the number of Herminium lanceum was positively correlated with vegetation significantly, the number of whole genus of Herminium was positively correlated with elevation moderately. In general, the orchid resources in Gexigou Nature Reserve are relatively rich, and more distribute in the middle elevation. The number of some species is significantly correlated with environmental factors. Compared with the previous investigations in this reserve, the number of orchid species is significantly increased. However, three national protected species of Cypripedium with high ornamental value were not found, and the population of one species of Cypripedium decreased. Therefore, it is urgent to protect, publicize and enforce the law on orchids in the reserve.

In the Orchidaceae family, Paphiopedilum exhibits extraordinary ornamental value and promising market prospects due to its unique appearance. However, Paphiopedilum is at risk of extinction worldwide due to slow growth rate, high environmental demands, and continuous collection by humans. Artificial seedlings can serve as a potential solution for ex situ conservation, reintroduction and commercial production. Unfortunately, artificial propagation is challenged due to low seed germination rate, slow growth rate, and limited resistance to ecological environments. Mycorrhizal symbiosis between plants and fungi has played a crucial role in the natural development of Paphiopedilum, particularly endophytic fungi, which significantly contribute to seed germination and plant growth. This article presents an analysis of features of endophytic fungi of Paphiopedilum, methods of endophytic fungi separation, types and functions of research, and the application prospects, while also outlining future research direction for the conservation of wild Paphiopedilum, seed germination and commercialization. This study aims to provide a comprehensive reference for future research on Paphiopedilum conservation, seed germination and commercialization.

In order to further investigate the anthocyanin biosynthetic pathway in Phalaenopsis-type Dendrobium (Den-Phals) varieties with different flower color, this study used widely targeted metabolomics technology to analyze the anthocyanin composition and content of five Den-Phals varieties with blue-purple, light peach-red, red, purple-red and deep purple-red floral color, respectively. The results showed that a total of 38 metabolites were identified from the tested Den-Phals, most of which were glycosides and acylated derivatives of cyanidin (Cy), peonidin (Pn), pelargonidin (Pg), delphinidin (Dp) and petunidin (Pt). There were significant differences in the composition and content of anthocyanin in five Den-Phals varieties. Metabolite difference analysis showed that Cy and Dp glycosides in purple flowers were significantly higher than those in light peach red flowers. The contents of three Dp-type glycosides in blue-purple flowers were significantly higher than those in other colored varieties. Only one Cy-type glycoside was screened out, and the content of which in light pink flowers was high. The content of Cy-type glycosides was the highest in most samples. With the increase of cyanidin and delphinidin and the derivatives, the color of flowers deepened and turned to red-purple. It was speculated that Cy-type glycosides made Den-Phals tend to purple while Dp glycosides gave Den-Phals a blue-purple tone. Based on the above results, it is speculated that there are acylation synthesis pathways of the above five anthocyanins in Den-Phals, which can provide a basis for flower color formation mechanism and flower color improvement of Den-Phals.

Phalaenopsis I-Hsin Venus is an excellent variety of fragrant flowers, with elegant flower types, long flowering period and rich floral fragrance, which has high garden ornamental value. ACT1, ACT2, ACT3, GAPDH, EF1α, TUA, TUB and Ubi, were selected as the candidate internal reference genes based on the transcriptome data of different flower development stages in Phal. I-Hsin Venus to select the appropriate reference genes for RT-qPCR analysis of the correlated genes in the biosynthesis pathway of the floral scent in Phalaenopsis I-Hsin Venus. The expression of the candidate internal reference genes in inflorescences at different stages was detected by RT-qPCR. The candidate internal parameter genes were analyzed by combining three internal parameter gene stability analysis software: geNorm, NormFinder and BestKeeper. The results of comprehensive analysis showed that ACT1 was the most stable and could be used as the best internal reference gene for the expression analysis of Phal. I-Hsin Venus.

NAC transcription factors are a large gene family in plants which play important roles in regulating plant growth and development, signal transduction, stress response, etc. In the previous study, the NAC gene, named MiNAC7, was isolated by the yeast two-hybrid system. In this study, the bioinformatics, expression patterns and gene functions of genes were studied. Bioinformatics analysis showed that the MiNAC7 gene was located on chromosome 10, with 4 introns and 5 exons. The length of the coding region of the MiNAC7 gene was 1137 bp, encoding 379 amino acids, the theoretical isoelectric point was 4.88, the molecular weight of the protein was 93.41 kDa, and the amino acid sequence contained a conserved NAM domain. Phylogenetic tree analysis showed that mango MiNAC7 and pistachio PvNAC26 had the closest genetic relationship and the highest homology, and the amino acid sequence similarity was 69.64%. Promoter sequence analysis showed that the promoter region of the MiNAC7 gene contained light response elements, gibberellin response elements and auxin response elements. Expression analysis showed that the expression level of the MiNAC7 gene was high in the stems and buds of juvenile tissues, low in flowers, high in the stems of adult tissues, and low in flowers and leaves. At the same time, it was found that the MiNAC7 gene maintained a high expression level in the leaves at the vegetative growth stage and a low expression level in the leaves at the flowering transformation stage and flower development stage. Overexpression of the MiNAC7 gene led to a late-flowering phenotype in transgenic Arabidopsis. The overexpression of the MiNAC7 gene in Arabidopsis significantly reduced the expression level of the floral-promoting genes AtFT and AtAP1, while the expression level of the late-flowering gene AtFLC was significantly increased. Stress treatment showed that Arabidopsis with excessive expression of the MiNAC7 gene improved its resistance to drought and salt and improved its resistance to GA₃ but was more sensitive to ABA. This study shows that the mango MiNAC7 gene not only affects flowering but also participates in the response to abiotic stress, which would lay a foundation for further research on the gene regulatory network of the MiNAC7 gene involved in regulating mango flowering and stress response.

Rubber tree is the most important cultivated rubber-producing plant, and the tapping of trunk is the only way to obtain natural rubber from the laticifer in the bark currently. The characteristics of latex flow after tapping determine the latex yield, but the mechanism of latex flow is not yet completely clear. The turgor pressure of bark is the main initial driving force for latex flow, and the content of lignin, as the main component of cell wall, is closely related to the turgor pressure. At present, the study on the lignin content in bark of rubber tree is deficiency, among which the analysis of lignin content by morphological structure is lack. Using the bark of RY8-79 and PR107 mature tree as the research materials, paraffin sections were prepared, and the lignin in the bark was stained and localized by Wiesner reaction, Mäule reaction, and safranin staining combined with fluorescence, respectively. The results showed that both Wiesner reaction and Mäule reaction could stain the lignin component of the parenchyma cell wall, but difficult to distinguish different strains and tissues for the light color. The light purplish red of lignin in the parenchyma cell could be observed after safranin staining, but it was also difficult to distinguish different tissues and strains. The obvious red fluorescence of lignin tissue could be observed after safranin staining combined with 546 nm green light excitation, and there was significant difference among different cell types and strains. The lignin fluorescence of parenchyma cell in RY8-79 was significantly weaker than that in PR107, indicating that the content of lignin in RY8-79 was lower than that in PR107. Iodine-bromine staining showed that the distribution of secondary laticifer was consistent with the distribution of lignin with strong fluorescence, indicating that the lignin content of secondary laticifer and its surrounding parenchyma cells increased significantly, especially in PR107. In addition, Wiesner and Mäule reaction needed dangerous chemical reagents such as phloroglucinol, hydrochloric acid and potassium permanganate (KMnO₄), respectively, and the reaction time was not easy to control for slices falling off from slides and cell wall damage. By comparison, the reagents used for safranin staining combined with fluorescence observation were safe and non-toxic, and the structure of cell in bark could maintain intact easily. According to the comprehensive analysis of different methods, for the excellent clarity of lignin as well as safety and simplicity of operation, safranin staining combined with fluorescence observation is the most suitable method for lignin location in parenchyma cell of rubber tree bark.

HSP90 is a key component in maintaining intracellular homeostasis, and it controls multiple cellular processes by regulating the maturation, stability, activity and turnover of its substrates. Rubber tree (Hevea brasiliensis Müll. Arg.) is an important source for the production of natural rubber, which has thousands of industrial uses and a high socioeconomic value. Using PCR technique, an HSP90 family member gene, named HbHSP90.6 gene (GenBank accession number: OP375588), was cloned from rubber tree variety Reyan73397 latex, and the sequence analysis showed that its coding region (CDS) was 2112 bp. Physicochemical analysis showed that its relative molecular weight was 80 774.85 Da, isoelectric point was 5.04, instability coefficient was 38.98, and total average hydrophilicity was -0.610, presumably HbHSP90.6 protein is a stable hydrophilic protein. The results of conserved structural domain analysis and multiple sequence alignment showed that HbHSP90.6 contained a structural domain of PTZ00272 and a highly conserved MEEVD motif, which is a member of the HSP90 family. Phylogenetic analysis showed that HbHSP90.6 clustered with Arabidopsis AtHSP90.1 (NM_124642.4) and rice OsHsp90-1 (LOC_Os04g01740) with 92.34% and 86.44% homology, respectively. Tissue expression analysis showed that the gene expression of HbHSP90.6 gene in latex was significantly higher than that in root, flower, branche, stem and leaf, and the expression of HbHSP90.6 gene in latex reached 283-fold relative to flowers, presumably the HbHSP90.6 gene may be involved in intracellular transport of latex tubes and regulation of latex metabolism. Mechanical wounding treatment in latex significantly upregulated the expression of HbHSP90.6 gene by 19 fold compared to the pretreatment pair, and it is hypothesized that HbHSP90.6 gene is involved in mechanical wounding regulated physiological and metabolic activity responses in rubber trees. The expression of HbHSP90.6 gene reached the highest level at 6 h of treatment with the phytohormones ethephon, jasmonic acid and 3-Indoleacetic acid, which were 45 fold, 17 fold and 6 fold higher than before treatment, respectively. The expression of HbHSP90.6 gene was significantly upregulated at 12 h after brassinosteroids treatment, reaching 50 fold of the pretreatment expression, presumably the HbHSP90.6 gene is involved in phytohormone mediated transcriptional regulation. Subcellular localization was performed by constructing a 35S::HbHSP90.6::GFP fusion expression vector, and the results showed that the HbHSP90.6 gene was localized in the cytoplasm and nucleus, which was consistent with the predicted results of subcellular localization. The results of this study would provide a thorough basis for elucidating the molecular mechanisms of HbHSP90.6 gene in plant hormone signaling-regulated stress and latex metabolism in rubber trees.

Information management of germplasm resources is the only way to improve the efficiency of germplasm resource management, sharing is an important means to activate the utilization value of preserved germplasm resources and realize the multiplier effect of seed industry, benefit distribution in sharing activities is the original incentive to promote germplasm resource sharing, and benefit ownership certificate is the key basis for benefit distribution. At present, the management of tropical crop germplasm resources is faced with the following problems: decentralized management of resource flow business chain; distortion of information data of resources and business chain; lack of evidence chain of credible benefit distribution of resources. To solve these problems, based on block chain technology, we put forward a kind of block chain system for tropical crop germplasm resources management to solve the problem of information asymmetry, by using decentralization, tamper-resistant, marks keeping in whole process, traceability, collective maintenance, and transparency, so as to realize the many relevant institutions of tropical crop germplasm resources and link collaboration trust and consistent action, effectively address the above issues and challenges. The system can keep marks processed and trace back to source, in full life cycle of tropical germplasm resources, laid the foundation for the combination of agriculture and computer agriculture, and resource traceability issues research. It is of great significance to the efficient management of tropical crop germplasm resources and the mining of potential value.