Search Results (200)

Grafting serves as a crucial propagation technique for superior Camellia oleifera varieties, where rootstock–scion compatibility significantly determines survival and growth performance. To systematically evaluate grafting compatibility in this economically important woody oil crop, we examined 15 rootstock–scion combinations using ‘Xianglin 210’ as the scion, assessing growth traits and conducting physiological assays (enzymatic activities of SOD and POD and levels of ROS and IAA) at multiple timepoints (0–32 days post-grafting). The results demonstrated that Comb. 4 (Xianglin 27 rootstock) exhibited superior compatibility, characterized by systemic antioxidant activation (peaking at 4–8 DPG), rapid auxin accumulation (4 DPG), and efficient sugar allocation. Transcriptome sequencing and WGCNA analysis identified 3781 differentially expressed genes, with notable enrichment in stress response pathways (Hsp70, DnaJ) and auxin biosynthesis (YUCCA), while also revealing key hub genes (FKBP19) associated with graft-healing efficiency. These findings establish that successful grafting in C. oleifera depends on coordinated rapid redox regulation, auxin-mediated cell proliferation, and metabolic reprogramming, with Comb. 4 emerging as the optimal rootstock choice. The identified molecular markers not only advance our understanding of grafting mechanisms in woody plants but also provide valuable targets for future breeding programs aimed at improving grafting success rates in this important oil crop. Full article

Camellia vietnamensis grows in a unique tropical environment, and its seed oil has a rich aroma. The content of unsaturated fatty acids in C. vietnamensis oil is up to 90%, which can regulate human lipid metabolism and prevent cardiovascular and cerebrovascular diseases. Compared with olive oil, C. vietnamensis oil has a higher content of unsaturated fatty acids. This study used eleven C. vietnamensis cultivars cultivated on Hainan Island. Among the 11 cultivars, “Boao 1” had fruits with the largest vertical diameter of 45.05 mm, while “Haida 1” had fruits with the largest horizontal diameter, single-fruit weight, and fresh 100-grain weight of 53.5 mm, 70.6 g, and 479.01 g, respectively. “Boao 3” had an acid value and peroxide value of 1.59 mg/g and 3.50 mmol/kg, respectively, and its saponification value content was 213.18 mg/g. “Boao 5” had the highest iodine value, 101.86 g/100 g, among the 11 cultivars. The content of unsaturated fatty acids in the seed oil of 11 cultivars ranged from 84.87% to 87.38%. The qRT-PCR results confirmed that “Boao 3” had a higher content of flavonoids and fatty acids than other cultivars. The comprehensive analysis of physiological and biochemical indices showed that the top five cultivars were “Haida 1”, “Boao 3”, “Haida 2”, “Boao 1”, and “Boao 5”. These five cultivars were suitable for large-scale cultivation in tropical regions, such as Hainan Island. This study provided a theoretical basis for the breeding of C. vietnamensis cultivars in tropical regions. Full article

Flowering is a key agronomic trait that directly influences the yield of the tea-oil tree (Camellia oleifera). Floral initiation, which precedes flower bud differentiation, represents a critical developmental stage affecting the flowering outcomes. However, the molecular mechanisms underlying floral initiation in C. oleifera remain poorly understood. In this study, buds from five key developmental stages of a 12-year-old C. oleifera cultivar ‘changlin53’ were collected as experimental samples. Scanning electron microscopy was employed to identify the stage of floral initiation. UPLC-MS/MS was used to analyze endogenous gibberellin (GA) concentrations, while transcriptomic analysis was performed to reveal the underlying transcriptional regulatory network. Six GA types were detected during floral initiation and petal development. GA₄ was exclusively detected at the sprouting stage (BII), while GA₃ was present in all samples but was significantly lower in BII and the flower bud primordium formation stage (BIII) than in the other samples. A total of 64 differentially expressed genes were concurrently enriched in flower development, reproductive shoot system development, and shoot system development. Weighted gene co-expression network analysis (WGCNA) identified eight specific modules significantly associated with different developmental stages. The magenta module, containing Unigene0084708 (CoFT) and Unigene0037067 (CoLEAFY), emerged as a key regulatory module driving floral initiation. Additionally, GA20OX1 and GA2OX8 were identified as candidate genes involved in GA-mediated regulation of floral initiation. Based on morphological and transcriptomic analyses, we conclude that floral initiation of C. oleifera is a continuous regulatory process governed by multiple genes, with the FT-LFY module playing a central role in the transition from apical meristem to floral meristem. Full article

Camellia oleifera is one of the four largest woody oil species in the world, with more than 5 million hectares planted in China alone. Reducing bud damage and improving harvesting net rate and efficiency have become the key challenges to mechanized harvesting of Camellia oleifera fruits. This paper presents a novel comb-spiral impact harvesting device primarily composed of four parts, which are lifting mechanism, picking mechanism, rotating mechanism, and tracked chassis. The workspace of the four-degree-of-freedom lifting mechanism was simulated, and the harvesting reachable area was maximized using MATLAB R2021a software. The picking mechanism, which includes dozens of spirally arranged impact pillars, achieves high harvesting efficiency through impacting, brushing, and dragging, while maintaining a low bud shedding rate. The rotary mechanism provides effective harvesting actions, and the tracked chassis guarantees free movement of the equipment. Simulation experiments and field validation experiments indicate that optimal performance can be achieved when the brushing speed is set to 21.45 r/min, the picking finger speed is set to 341.27 r/min, and the picking device tilt angle is set to 1.0°. With these parameters, the harvesting quantity of Camellia oleifera fruits is 119.75 kg/h, fruit shedding rate 92.30%, and bud shedding rate as low as 9.16%. This new model for fruit shedding and the comb-spiral impact harvesting principle shows promise as a mechanized harvesting solution for nut-like fruits. Full article

Seed germination is a critical phase in the plant lifecycle of Camellia oleifera (oil tea), directly influencing seedling establishment and crop reproduction. In this study, we examined transcriptomic and physiological changes across five defined germination stages (G0–G4), from radicle dormancy to cotyledon emergence. Using RNA sequencing (RNA-seq), we assembled 169,652 unigenes and identified differentially expressed genes (DEGs) at each stage compared to G0, increasing from 1708 in G1 to 10,250 in G4. Functional enrichment analysis revealed upregulation of genes associated with cell wall organization, glucan metabolism, and Photosystem II assembly. Key genes involved in cell wall remodeling, including cellulose synthase (CESA), phenylalanine ammonia-lyase (PAL), 4-coumarate-CoA ligase (4CL), caffeoyl-CoA O-methyltransferase (COMT), and peroxidase (POD) showed progressive activation during germination. A Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed dynamic regulation of phenylpropanoid and flavonoid biosynthesis, photosynthesis, carbohydrate metabolism, and hormone signaling pathways. Transcription factors such as indole-3-acetic acid (IAA), ABA-responsive element binding factor (ABF), and basic helix–loop–helix (bHLH) were upregulated, suggesting hormone-mediated regulation of dormancy release and seedling development. Physiologically, cytokinin (CTK) and IAA levels peaked in G4, antioxidant enzyme activities were highest in G2, and starch content increased toward later stages. These findings provide new insights into the molecular mechanisms underlying seed germination in C. oleifera and identify candidate genes relevant to rootstock breeding and nursery propagation. Full article

As a unique woody oil crop in China, Camellia oleifera Abel. germplasm resources show significant genetic diversity in Ya’an City. This study measured 60 phenotypic traits (32 quantitative, 28 qualitative) of 302 accessions to analyze phenotypic variation, establish a classification system, and screen high-yield, high-oil germplasms. The phenotypic diversity index for fruit (H’ = 1.36–1.44) was significantly higher than for leaf (H’ = 1.31) and flower (H’ < 1), indicating genetic diversity concentrated in reproductive traits, suggesting potential genetic variability in these traits. Fruit quantitative traits (e.g., single fruit weight CV = 35.37%, fresh seed weight CV = 38.93%) showed high genetic dispersion. Principal component analysis confirmed the fruit factor and economic factor as main phenotypic differentiation drivers. Quantitative traits were classified morphologically, and correlation analysis integrated them into 13 key indicators classified using LSD and range methods. Finally, TOPSIS evaluation selected 10 excellent germplasms like TQ122 and TQ49, with fruit weight, fresh seed yield, and kernel oil content significantly exceeding the population average. This study provides data for C. oleifera DUS test guidelines and proposes a multi-trait breeding strategy, supporting high-yield variety selection and germplasm resource protection. Full article

Hioredoxins are small proteins crucial for maintaining cellular redox balance and are involved in various biological processes, including growth, photosynthesis, development, and stress responses. This study aims to conduct a genome-wide analysis of the typical Thioredoxin (TRX) gene family in hexaploid Camellia oleifera and explore the role of the CoTRX25 gene in flowering. Through bioinformatics approaches, we identified 27 typical TRX gene family members in the C. oleifera genome and analyzed their phylogenetic relationships, gene structures, conserved motifs, and chromosomal distributions. Transcriptomic analysis across different tissues was performed to determine the expression patterns of these genes. Additionally, the CoTRX25 gene was cloned and heterologously overexpressed in Arabidopsis thaliana to investigate its functional role in flowering. The 27 TRX genes were mainly located on 11 chromosomes, with multiple gene duplication events identified, indicating that gene duplication has played a significant role in the expansion of the TRX family. Transcriptomic analysis revealed that most typical TRX genes are highly expressed in embryos, suggesting their potential importance in seed development. Overexpression of CoTRX25 in A. thaliana led to delayed flowering, implying that this gene may be involved in flowering regulation. This study provides a theoretical basis for understanding the functions of typical TRX genes in C. oleifera growth and development, particularly highlighting the role of CoTRX25 in flowering regulation. Full article

Phytosterols (PS) have specific oxidation rules in different lipid media. After oxidation, PS will form oxidation products, which has potential physiological toxicity to the human body. Camellia seed oil (CSO) is a unique emerging edible oil in China. This oil has a fatty acid composition similar to olive oil, in which oleic acid is dominant. In order to solve the thermal oxidation of PS in CSO at high temperature (180 °C), we studied its antioxidant strategy by evaluating different antioxidants. Four antioxidants—BHA, TBHQ, epigallocatechin gallate (EGCG), and α-tocopherol (VE)—along with one synergist, citric acid (CA), were selected and used in this study. The antioxidant effects of different combinations (single antioxidant, single antioxidant + CA, mixed antioxidant, mixed antioxidant + CA) were compared. After 180 min of heating, the PS and phytosterols oxidation products (7α-hydroxy-, 7β-hydroxy-, 5α,6α-epoxy-, 5β,6β-epoxy-, 7-keto-, and trihydroxy-PS) were estimated by GC-MS. Through comparative analysis, the results showed that the combination of mixed antioxidants and CA had the best antioxidant effect, and the inhibition rate of VE + TBHQ +CA was as high as 42%, which had a breakthrough significance for stabilizing the thermal oxidation of PS in camellia seed oil. At the same time, it also provides a valuable reference for ensuring the edible safety of camellia seed oil in Chinese food heating habits. Full article

Camellia chekiangoleosa Hu. (C. chekiangoleosa) is a typical high-altitude oil-tea Camellia species. Due to altitude being an important factor affecting crop growth and quality, the influence of environmental conditions associated with low (60 m) and high (600 m) altitudes on the economic and quality characteristics of fruit ripening was assessed in this study. Our investigations showed that altitude has no influence on the growth pattern of C. chekiangoleosa fruit shells and seed oils, and the differences in samples between different altitudes gradually decreased with the ripening of C. chekiangoleosa. Nevertheless, mature C. chekiangoleosa fruit shells and seed oils from low and high altitudes showed some differences. Specifically, the fruit shells of C. chekiangoleosa cultivated in low-altitude areas contained more soluble sugar, protein, total polyphenols, total flavonoids, and tea saponin. Meanwhile, low-altitude cultivation elevated the abundance of α-tocopherol, β-sitosterol, β-amyrinol, flavonoids, and polyphenols in mature seed oils but decreased the oil yield. Moreover, few effects of altitude on fatty acid composition were observed in mature seed oils. Cluster and receiver operating characteristic (ROC) analysis indicated that the influence of altitude on the quality of mature seed oils was strongly associated with oil yield and α-tocopherol. Taken together, the present study suggests that when cultivating C. chekiangoleosa in low-altitude regions, more energy should be devoted to improving oil yield. The results of the fruiting process and quality trait variation in C. chekiangoleosa during the low-altitude introduction process can provide an important theoretical basis for the introduction and cultivation of this oil-tea species. Full article

Essential oils (EOs) represent natural bioactive agents with broad applications; however, their industrial utilization is often hampered by inherent volatility and instability, which current encapsulation methods struggle to overcome due to limitations such as reliance on synthetic surfactants. Proteins, owing to their amphiphilic nature, serve as materials for EOs microencapsulation, particularly when chemically modified. Building upon our previous work demonstrating improved emulsifying properties of hemp seed protein isolate (HPI) through covalent modification with gallic acid (GA), this study investigated its efficacy for essential oil encapsulation. This study developed a novel microencapsulation system utilizing conjugates of HPI and GA for stabilizing six essential oils (lemon, grapefruit, camellia, fragrans, oregano, and mustard). The microcapsules exhibited encapsulation efficiencies (EE) ranging from 40% to 88%, with oregano oil demonstrating superior performance due to carvacrol’s amphiphilic surfactant properties. Advanced characterization techniques revealed that high-EE microcapsules displayed compact morphologies, enhanced thermal stability, and reduced surface oil localization. Release kinetics followed either the Peppas or Weibull model, with oregano microcapsules achieving sustained release via matrix erosion mechanisms. Antioxidant assays and antimicrobial tests demonstrated multifunctional efficacy, where oregano microcapsules exhibited the highest radical scavenging and antimicrobial activity. These findings establish HPI-GA conjugates as unique dual-functional emulsifier-encapsulants, offering a sustainable and effective platform to enhance EO stability and bioactivity, particularly for applications in food preservation and pharmaceutical formulations. Full article

Camellia oleifera Abel (C. oleifera) is an evergreen shrub classified under the Camellia genus. It is an important oil species and has great economic benefits. At present, C. oleifera is widely cultivated in the Yangtze River Basin in South China, and its wild species are mainly distributed in the native forests of Hainan Province. Therefore, in the current study, we used the MaxEnt model to predict the suitable habitat for C. oleifera and different environmental factors affecting its current and future distribution. The AUC values exceeded 0.98, showing that the simulation of the model was good, and the TSS values were all above 0.96, indicating that the model was feasible. The results showed that C. oleifera was mainly distributed in Southern China, with a total area of 56.68 × 10⁴ km². The suitable habitats of Camellia oleifera are affected by the precipitation of the warmest quarter (bio18), human activity, soil available water content (awc_class), and minimum temperature of the coldest month and seasonal temperature (bio04). Furthermore, rainfall in the warmest quarter (bio18) was recognized as a crucial factor impacting its distribution. Under future climate conditions, the suitable habitat area of C. oleifera is projected to expand with a slight northward shift in its distribution center. Therefore, in addition to maintaining the current planting area of C. oleifera, the planting area can be appropriately expanded upward along the current area and along the Yangtze River Basin. Full article

Camellia oleifera, a prominent species of edible oil tree in China, depends on improved soil fertility for its sustainable growth. Although the application of bacterial manure has been demonstrated to enhance soil nutrient conditions, the specific contributions of endophytes within fertilizers and their interactions with soil microbial ecosystems remain inadequately explored. This study investigates the impact of organic fertilizers combined with three endophytes (CoT10, CoH27, and CoH17) on the physicochemical properties, enzymatic activities, and microbial diversity of soils in C. oleifera plantations. Findings indicate that the integration of endophytes with organic fertilizers significantly improved soil nutrient levels (including total nitrogen, total phosphorus, and hydrolysable nitrogen), enzymatic activities (such as phosphatase, amylase, and nitrate reductase), and microbial diversity compared to the application of organic fertilizer alone. Notably, the endophyte CoT10, when applied alone with organic fertilizer, resulted in increased levels of total nitrogen, total phosphorus, and hydrolysable nitrogen in the soil, as well as a marked enhancement in the activities of soil phosphatase, amylase, and nitrate reductase. Furthermore, the combination of CoT10 with other endophytes in organic fertilizer improved the functionality of the other microorganisms and the efficiency of organic fertilizer utilization. This study underscores the synergistic effects of endophytes and organic fertilizers, providing scientific insights and practical strategies for the sustainable cultivation of C. oleifera. Full article

Oil-tea (Camellia oleifera), a typical oilseed tree, produces high-quality edible vegetable oils that contain rich unsaturated fatty acids and diverse lipid-soluble active compounds such as squalene. Although squalene biosynthesis and its molecular regulation have been studied in several plants, the molecular mechanisms underlying squalene biosynthesis in oil-tea seeds remain uncertain. We investigated and determined squalene accumulation with seed development. We conducted comparative transcriptomic analyses using the RNA-seq technique at the early, fast biosynthesis, and late stages of squalene accumulation with oil-tea seed development and identified 13 squalene biosynthesis key enzyme genes (such as CoHMGR_4, CoAACT_2, CoFPS_1, and CoFPS_2) in developing oil-tea seeds. According to whether the expressions of key enzyme genes were associated with squalene accumulation we found that the precursor IPP of squalene biosynthesis obtained via the MVA pathway was dominant with oil-tea seed development. Based on the gene co-expression analyses, we identified multiple transcription factors potentially involved in regulating squalene biosynthesis such as CoMYC2, CoREM39, CobZIP5, CoERF and CoWRKY. Using yeast one-hybrid and dual-luciferase assay experiments we demonstrated that the transcription factor CoMYC2 could activate the expression of a key enzyme gene CoHMGR_4, suggesting that CoMYC2 might be a critical regulator during squalene biosynthesis in oil-tea seed development. This study gives not only insights into understanding the molecular basis of squalene biosynthesis in oil-tea developing seeds but also provides gene resources for developing genetically improved varieties with higher content of squalene in oil-tea. Full article

Camellia oil, rich in monounsaturated fatty acids, squalene, tocopherols, and polyphenols, is highly valued for its nutritional benefits. However, its high market value and regional variations have led to frequent adulteration, highlighting the need for rapid, non-destructive methods for authentication, geographical traceability, and quality assessment. This study employed portable Raman spectroscopy combined with Partial Least Squares Discriminant Analysis (PLS-DA) and Multivariate Curve Resolution–Alternating Least Squares (MCR-ALS) to differentiate camellia oil from other edible oils and evaluate its thermal and photo-oxidative stability. PLS-DA, based on VIP-selected spectral variables, effectively distinguished camellia oil, with Raman bands near 1250 cm⁻¹ and 1650 cm⁻¹ contributing significantly. A unique peak at 1525 cm⁻¹, observed in samples from Gongcheng, Guangxi, was associated with carotenoids and served as a potential marker for geographical traceability. MCR-ALS modeling revealed significant reductions in the 1650 cm⁻¹ and 1525 cm⁻¹ peaks when temperatures exceeded 150 °C, indicating degradation of unsaturated fatty acids and carotenoids. Under UV exposure, the 1525 cm⁻¹ peak declined sharply and nearly disappeared after 24 h, suggesting rapid carotenoid degradation via photooxidation. Extended UV treatment also affected the 1650 cm⁻¹ peak and led to oxidative product accumulation. Overall, this study demonstrates the feasibility of integrating Raman spectroscopy with chemometric analysis for efficient oil classification, traceability, and stability monitoring, offering a valuable tool for food quality control and market supervision. Full article

To address the low shelling rate and high seed breakage in existing oil tea fruit shelling devices, a novel laser scoring device was designed for fresh Camellia oleifera fruits. Experimental studies were conducted to optimize the key parameters of the custom-built laser scoring machine, aiming to improve scoring qualification rates. Through single-factor tests and response surface methodology, a regression model was developed to characterize the relationship between the scoring qualification rate and the following three variables: conveyor speed (12 mm/s), laser power (97 W), and defocusing distance (10 mm). The study revealed interactive effects among these parameters. After optimization and verification under ideal conditions, the device achieved a peak average qualification rate of 85.6%. Full article