Search Results (10)

Oncidium has an important market value, with important high-grade cut orchids and potted flowers on the flower market. In the Oncidium cut flowers production industry, there is a common phenomenon that the development of vegetative buds disrupts the normal generation cycle of the inflorescence induction, so-called “bud jumping”. In this study, vegetative bud differentiation and flower bud differentiation were divided into three stages, namely, the initial stage of differentiation, the leaf primordial/flower primordial differentiation stage, and the late stage of leaf bud/flower bud differentiation, as observed by paraffin sectioning. Secondly, we analyzed the differences between the vegetative buds of “bud jumping” plants and the flower buds of normal flowering plants by transcriptome sequencing. The transcriptome analysis results revealed significant differences among plant signaling pathways, particularly in gibberellins, auxins, and cytokinins, which play important roles in this phenomenon’s formation. In conjunction with the transcriptome analysis, the researchers conducted field experiments by applying plant growth regulators on the newborn pseudobulb of young Oncidium plants measuring approximately 49 mm in length. The results showed that the treatment groups of 100 mg/L of gibberellic acid (GA₃) and 100 mg/L GA₃ + 10 mg/L 6-Benziladenine (6-BA) exhibited the highest rate of flower bud differentiation instead of the least “bud jumping” phenomenon, and the “bud jumping” phenomenon was significantly reduced under 25 mg/L, 50 mg/L, and 75 mg/L 3-indoleacetic acid (IAA) treatments. The application of exogenous gibberellins, cytokinins, and auxins can effectively reduce the occurrence of “bud jumping”. Full article

The cut flowers of the Oncidium hybridum cultivar ‘Honey Angle’ are highly regarded for their vibrant floral display, excellent flower quality, and broad commercial applications. However, its postharvest vase life is significantly challenged by wilting, water loss, and color fading, primarily due to ethylene exposure. To clarify the underlying mechanism, we performed treatments with ethylene and ethylene action inhibitor 1-Methylcyclopropene (1-MCP). The petal changes, vase life, and transcriptomic analysis after treatments were investigated. The results revealed that the 1-MCP treatment significantly extended the vase life by upregulating the genes involved in carotenoid synthesis, suppressing the genes related to cell wall degradation and the ethylene signaling pathways. In contrast, the ethylene treatment accelerated senescence by activating the senescence-related genes and increasing ethylene production. Transcriptome analysis identified 960 transcription factors, predominantly from the NAC, WRKY, ERF, bHLH, and MYB families, which were crucial in regulating quality changes during the vase life. A total of 5203 differentially expressed genes (DEGs) were assigned to 19 KEGG pathways including carbohydrate and energy metabolism as well as plant hormone signal transduction. Weighted gene co-expression network analysis (WGCNA) indicated that these DEGs were primarily associated with weight loss, flowering ratio, lightness, maximum petal diameter, and respiration intensity. This research provided valuable insights into the molecular mechanisms of floral senescence and practical guidance for extending the vase life of ‘Honey Angle’ cut flowers. Full article

The aim of this study was to evaluate the growth and flowering characteristics of three Oncidesa cultivars under four distinct canopy treatments in a greenhouse environment. The control canopy treatment (canopy D) involved covering the greenhouse with black shade nets to reduce natural light penetration. Canopy B included black shade nets in combination with a transparent plastic screen on the sides to further modify the light conditions. Additionally, two other treatments were applied: black shade nets with (canopy A) or without (canopy C) plastic sheeting, supplemented with daily lighting from high-pressure sodium lamps. Ten horticultural traits were measured to assess the impact of these canopy treatments on different cultivars at various growth stages. The results show that canopy treatments significantly affected all the measured traits of the Oncidesa cultivars, except for leaf width. Apollo plants treated under canopy A exhibited longer and thicker pseudobulbs, wider leaves, higher chlorophyll content, and a greater number of branches and florets compared to Honey Angel and Golden Star. Plants under canopy C showed superior growth traits across all cultivars, while those under canopies A and D exhibited better flowering quality. These findings suggest that different canopy treatments had varying effects on the growth and flowering traits of Oncidesa cultivars, with each cultivar showing distinct adaptability to specific canopy conditions. Full article

Oncidium hybridum is one of the important cut-flowers in the world. However, the lack of aroma in its cut-flower varieties greatly limits the sustainable development of the Oncidium hybridum cut-flowers industry. This paper is an integral investigation of the diel pattern and influencing factors of the aroma release of Oncidium Twinkle ‘Red Fantasy’. GC-MS analysis revealed that the release of 3-Carene peaked at 10:00, while Butyl tiglate and Prenyl senecioate did so at 14:00, with a diel rhythm. By analyzing the correlation network between aroma component synthesis and differentially expressed genes, 15 key structural genes were detected and regulated by multiple circadian rhythm-related transcription factors. Cluster-17371.18_TPS, Cluster-65495.1_TPS, Cluster-46699.0_TPS, Cluster-60935.10_DXS, Cluster-47205.4_IDI, and Cluster-65313.7_LOX were key genes in the terpenoid and fatty acid derivative biosynthetic pathway, which were co-expressed with aroma release. Constant light/dark treatments revealed that the diurnal release of 3-Carene may be influenced by light and the circadian clock, and Butyl tiglate and Prenyl senecioate may be mainly determined by endogenous circadian clock. Under constant light treatment, the TPS, DXS, IDI, and LOX genes seem to lose their regulatory role in the release of aroma compounds from Oncidium Twinkle ‘Red Fantasy’. Under constant dark treatment, the TPS genes were consistent with the release pattern of 3-Carene, which may be a key factor in regulating the diel rhythm of 3-Carene biosynthesis. These results laid a theoretical foundation for the study of floral transcriptional regulation and genetic engineering technology breeding of Oncidium hybridum. Full article

Oncidium hybridum Lodd. is an important ornamental flower that is used as both a cut flower and a potted plant around the world; additionally, its pseudobulbs serve as essential carriers for floral organs and flower development. The NAM gene family is crucial for managing responses to various stresses as well as regulating growth in plants. However, the mechanisms by which NAM genes regulate the development of pseudobulbs remain unclear. In this study, a total of 144 NAM genes harboring complete structural domains were identified in O. hybridum. The 144 NAM genes were systematically classified into 14 distinct subfamilies via phylogenetic analysis. Delving deeper into the conserved motifs revealed that motifs 1–6 exhibited remarkable conservation, while motifs 7–10 presented in a few NAM genes only. Notably, NAM genes sharing identical specific motifs were classified into the same subfamily, indicating functional relatedness. Furthermore, the examination of occurrences of gene duplication indicated that the NAM genes display 16 pairs of tandem duplications along with five pairs of segmental duplications, suggesting their role in genetic diversity and potential adaptive evolution. By conducting a correlation analysis integrating transcriptomics and metabolomics at four stages of pseudobulb development, we found that OhNAM023, OhNAM030, OhNAM007, OhNAM019, OhNAM083, OhNAM047, OhNAM089, and OhNAM025 exhibited significant relationships with the endogenous plant hormones jasmonates (JAs), hinting at their potential involvement in hormonal signaling. Additionally, OhNAM089, OhNAM025, OhNAM119, OhNAM055, and OhNAM136 showed strong links with abscisic acid (ABA) and abscisic acid glucose ester (ABA-GE), suggesting the possible regulatory function of these NAM genes in plant growth and stress responses. The 144 NAM genes identified in this study provide a basis for subsequent research and contribute to elucidating the intricate molecular mechanisms of NAM genes in Oncidium and potentially in other species. Full article

Plants are valuable sources of secondary metabolites with pharmaceutical properties, but only a small proportion of plant life has been actively exploited for medicinal purposes to date. Underexplored plant species are therefore likely to contain novel bioactive compounds. In this study, we investigated the content of secondary metabolites in the flowers, leaves and pseudobulbs of the orchid Oncidium sotoanum using an untargeted metabolomics approach. We observed the strong accumulation of C-diglycosylated chrysin derivatives, which are rarely found in nature. Further characterization revealed evidence of antioxidant activity (FRAP and DPPH assays) and potential activity against neurodegenerative disorders (MAO-B inhibition assay) depending on the specific molecular structure of the metabolites. Natural product bioprospecting in underexplored plant species based on untargeted metabolomics can therefore help to identify novel chemical structures with diverse pharmaceutical properties. Full article

Oncidium are grown worldwide and play important economic roles. The objective of this study was to investigate the pseudobulb growth and flowering characteristics of the two Oncidesa Gower Ramsey cultivars, ‘Honey Angel (HA)’ and ‘Golden Star (GS)’, cultivated under 3 kinds of fertilizer treatments in response to 40% light intensity (LI-40) and 30% light intensity (LI-30, as control) photosynthetic photon flux density over a 5-month period. The conventional-fertilizer (CF) treatment, as a control, consisted of a liquid manure solution of N:K = 1:1.12, mixed with 7.8% N, 0.8% P₂O₅, 0.3% K₂O, and 57.3% of organic matter that was foliage-applied to plants twice weekly. The stage-fertilizer (SF) treatment consisted of N:P:K = 1:1:5 foliage-applied to plants in an unsheathing pseudobulb stage until reaching inflorescence, followed by N:P:K = 1:1:1 application until the end of the experiment. The fortnight-fertilizer (FF) treatment consisted of N:P:K = 1:1:5 and N:P:K = 1:1:1 with interval-rotate foliage-application to plants weekly until the end of the experiment. Pseudobulb length (PL), pseudobulb major axis (PW), and pseudobulb minor axis (PT), and inflorescence length (FL), number of pedicel (FB), and floret numbers (FN) per plant were recorded and calculated from two months after pseudobulb maturity until the end of the five-month experimental period. The GS variety significantly increased PL when treated with CF and FF compared to HA, and GS treated with CF under LI-30 exhibited the longest PL at 81.65 mm. PW increased as LI increased under FF treatment, and the largest PW was observed in GS treated with FF under LI-40. A maximal and significant increase in PT occurred in LI-40 compared to LI-30 under the CF treatment. GS had a significantly higher FL compared to HA treated with CF, and the longest FL was detected in GS under LI-30. HA had a significantly higher FB and FN under LI-40 than under LI-30, and the highest number of FB and FN in HA occurred when it was treated with CF and SF, respectively. Precision management of fertilization treatments in response to LI can maximize pseudobulb growth, development, and flowering quality in Oncidesa species. Full article

In order to minimize the impacts of climate change on various crops, farmers must learn to monitor environmental conditions accurately and effectively, especially for plants that are particularly sensitive to the weather. On-site sensors and weather stations are two common methods for collecting data and observing weather conditions. Although sensors are capable of collecting accurate weather information on-site, they can be costly and time-consuming to install and maintain. An alternative is to use the online weather stations, which are usually government-owned and free to the public; however, their accuracy is questionable because they are frequently located far from the farmers’ greenhouses. Therefore, we compared the accuracy of kriging estimators using the weather station data (collected by the Central Weather Bureau) to local sensors located in the greenhouse. The spatio-temporal kriging method was used to interpolate temperature data. The real value at the central point of the greenhouse was used for comparison. According to our results, the accuracy of the weather station estimator was slightly lower than that of the local sensor estimator. Farmers can obtain accurate estimators of environmental data by using on-site sensors; however, if they are unavailable, using a nearby weather station estimator is also acceptable. Full article

Oncidium is an important ornamental crop worldwide, and in recent years, the characteristics of the flower aroma have become a concern for breeders. This study used headspace solid-phase microextraction (HS-SPME) and gas chromatography/mass spectrometry (GC-MS) analysis of the volatile compounds to study the aroma characteristics of Onc. Rosy Sunset. A total of 45 compounds were identified, with the major compound being linalool. Onc. Rosy Sunset had the highest odor concentration from 10:00 to 12:00 and lowest from 20:00 to 24:00. The inflorescence emitted the highest quantities of volatile compounds during stages 3–6, which then decreased with the aging of the flowers. In Onc. Rosy Sunset, the sepals and petals were the major parts for the floral fragrance emission, in which linalool content was the highest, whereas the lip and column had a different composition of major volatile compounds, of which benzaldehyde, β-myrcene, and β-caryophyllene dominated. Full article

The FLOWERING LOCUS T (FT) gene plays crucial roles in regulating the transition from the vegetative to reproductive phase. To understand the molecular mechanism of reproduction, three homologous FT genes were isolated and characterized from Cymbidium sinense “Qi Jian Bai Mo”, Cymbidium goeringii and Cymbidium ensifolium “Jin Si Ma Wei”. The three genes contained 618-bp nucleotides with a 531-bp open reading frame (ORF) of encoding 176 amino acids (AAs). Alignment of the AA sequences revealed that CsFT, CgFT and CeFT contain a conserved domain, which is characteristic of the PEBP-RKIP superfamily, and which share high identity with FT of other plants in GenBank: 94% with OnFT from Oncidium Gower Ramsey, 79% with Hd3a from Oryza sativa, and 74% with FT from Arabidopsis thaliana. qRT-PCR analysis showed a diurnal expression pattern of CsFT, CgFT and CeFT following both long day (LD, 16-h light/8-h dark) and short day (SD, 8-h light/16-h dark) treatment. While the transcripts of both CsFT and CeFT under LD were significantly higher than under SD, those of CgFT were higher under SD. Ectopic expression of CgFT in transgenic Arabidopsis plants resulted in early flowering compared to wild-type plants and significant up-regulation of APETALA1 (AP1) expression. Our data indicates that CgFT is a putative phosphatidylethanolamine-binding protein gene in Cymbidium that may regulate the vegetative to reproductive transition in flowers, similar to its Arabidopsis ortholog. Full article