Tea polyphenols are the most abundant active components in tea, with a variety of physiological functions. However, there is a lack of a systematic summary regarding the research history of tea polyphenols. This paper systematically reviewed the discovery, naming and functional application of tea polyphenols, while also briefly discussed their health benefits in immune regulation, anti-inflammation, and oxidative stress as well as the structural basis of the active hydroxyl groups in polyphenols. Consequently, it provided support for the application research of tea polyphenols in different fields. In addition, in view of the problems of poor stability and low bioavailability of tea polyphenols, we provided a brief overview of research on novel tea polyphenol nanobiomaterials. These nanobiomaterials exhibited the characteristics of high stability, safety and multi-functionality, which were anticipated to enhance the further application of tea polyphenols.

Nitrogen metabolism genes play a key role in tea plants′ response to various environmental stresses. They do this mainly by regulating metabolites in different pathways. In recent years, significant progress has been made in the study of nitrogen metabolism genes in tea plants using techniques such as transcriptome and metabolome analysis, genome identification. However, there are still many scientific problems that need to be solved urgently, such as the low genetic transformation efficiency of tea plants, the limited research on gene epigenetics, and the limited application of gene breeding in production. This article systematically summarized the expression patterns of nitrogen metabolism genes in tea plants under different stress conditions, organs, and soil elements, as well as the research progress on the regulation mechanism of carbon and nitrogen balance in tea plants under different stresses, revealing the importance of these genes in tea plant stress adaptation and quality improvement. In addition, the research methods, transgenic technology, and breeding applications of nitrogen metabolism genes in tea plants were discussed in order to provide reference for the study of nitrogen metabolism gene regulation mechanisms and breeding research in tea plants.

With the rapid development of the novel-tea beverage industry, market competition has significantly intensified. To enhance competitiveness, novel-tea beverage enterprises have increasingly adopted cross-border innovation strategies aimed at upgrading product quality, optimizing the consumer experience, and strengthening brand loyalty. However, the theoretical and empirical understanding of how cross-border innovation enhances brand loyalty is still limited. Utilizing quantitative empirical methods, this study investigated the impact of horizontal and vertical cross-border innovation on consumer brand loyalty based on survey data of 1 900 young novel-tea beverage consumers. The findings reveal that both forms of cross-border innovation contribute to strengthening brand loyalty, with upstream cultural integration within vertical cross-border innovation demonstrating the strongest effect. Furthermore, cross-border innovation primarily influences brand loyalty indirectly by satisfying consumers’ quality demands and enriching consumption experiences, with quality appeal serving as the core mediating mechanism. Additionally, the selection of cross-border innovation strategies is contingent upon enterprise positioning: high-end brands benefit more from horizontal and upstream cultural cross-border innovation, while mid-to-low-end brands achieve brand loyalty enhancement through scenario-based downward cross-border innovation. Based on the above conclusions, this paper proposed some countermeasures and suggestions on how to carry out cross-border innovation marketing.

Alkaloids, as a class of nitrogen-containing secondary metabolites characterized by remarkable chemical diversity, are widely distributed in higher plants, fungi, and bacteria. Most natural alkaloids possess biological activities such as antioxidant, anti-inflammatory, and anti-tumor effects. This review comprehensively summarized the identified alkaloid groups in tea and briefly analyzed their biological activities, including: (1) purine alkaloids, which regulate neural excitability by antagonizing adenosine receptors and inhibiting phosphodiesterase to regulate metabolic functions, exhibit anti-inflammatory, and other biological activities. (2) flavor alkaloids have effects in preventing diabetes and inhibiting cancer cell angiogenesis. (3) the mechanisms by which prenylated indole alkaloids exert anti-inflammatory effects, inhibit cancer cell growth and exert neuro-protective effects. Finally, the future research directions focusing on the identification, appraisal, synthesis and functional evaluation systems of tea alkaloids were proposed.

This study investigated the characteristic aroma components and microbial diversity during long term and short term fermentation processes of Anhua black tea. The research employed headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS), as well as 16 S rRNA and ITS high-throughput sequencing technologies. The results show that 82 volatile components were detected in Anhua black tea with distinct fermentation processes, mainly include alcohols, esters, and aldehydes, collectively accounting for approximately 85% of the total volatile content. The overall volatile components initially increased and subsequently decreased during processing. Based on thresholds of odor activity value (OAV)>1 and variable importance in projection (VIP)>1, 14 key differential volatile components were identified in the black tea of short and long term fermentation processes, including citral, linalool, phenethyl alcohol, phenylacetaldehyde, methyl salicylate, β-myrcene, β-ionone, et al. The dominant bacteria of Anhua black tea include Sphingomonas, Methylobacterium, Aureimonas, and the dominant fungi include Cladosporium, Alternaria and Setophoma. The genera Aureimonas, Enterobacter, Aspergillus, and Pseudopithomyces were significantly correlated with distinct fermentation processes. This study provided a theoretical reference and basis for the scientific processing and flavor analysis of Anhua black tea.

To further clarify the effects of the main compounds in white tea on blood glucose levels, the network pharmacology was used to conduct a correlation analysis between 8 main compounds in white tea and diabetes, and a zebrafish biological model was adopted for verification. The network pharmacology analysis reveals that blood glucose was primarily regulated by gallic acid, catechin group, and caffeine in white tea through four targets: TNF, p53, SRC and CASP3. The verification results of the zebrafish model show that the maximum tolerance concentrations of zebrafish to the different samples were as follows: 100.00 µg·mL^-1 (white tea soup), 6.25 µg·mL^-1 (gallic acid, caffeine), 12.50 µg·mL^-1 (EGCG), 25.00 µg·mL^-1 (ECG, EGC, GCG), 50.00 µg·mL^-1 (EC), and 150.00 µg·mL^-1 (C). At this concentration, the blood glucose values decreased significantly in all groups compared with the model group: the positive drug (ACA) group by 53.7%, the white tea soup group by 16.2%, the gallic acid group by 33.6%, the EGCG group by 47.3%, the ECG group by 30.0%, the EGC group by 52.6%, the GCG group by 25.8%, the EC group by 21.5%, and the C group by 29.4%. Only the caffeine group showed a significant blood glucose-elevating effect (P<0.05), with an increase of 16.9%. The qPCR results show that, compared with the blank group, the expression levels of TNF, SRC and CASP3 in the model group were significantly increased, while the expression level of TP53 was significantly decreased (P<0.05). Compared with the model group, the expression levels of TNF, SRC and CASP3 in the gallic acid and catechin groups were significantly decreased (P<0.05), while the expression level of TP53 was significantly increased (P<0.05). The expression levels of TNF and SRC in the caffeine group were significantly increased (P<0.05), while there were no significant differences in TP53 and CASP3. The results show that gallic acid and catechin components in white tea both exhibited significant hypoglycemic effects, which were mainly achieved by regulating four targets: TNF, p53, SRC and CASP3. In contrast, caffeine was found to have a significant blood glucose-elevating effect, primarily through TNF and SRC.

To investigate the taste quality of jasmine tea, UHPLC-Q Exactive-Orbitrap-MS combined with electronic tongue analysis was used to characterize the nonvolatile compounds and the taste qualities of base tea and jasmine green tea were evaluated in this research. Electronic tongue results show that the bitterness and astringency of pan-fired green tea, semi-baked stir-fry green tea and baked green tea decreased significantly, and the umami taste increased significantly. The results of sensory evaluation show that the aroma and taste quality of jasmine tea scented with pan-fired green tea were the highest, and the overall flavor quality was the best. A total of 7 compounds were identified as the key differential compounds of jasmine tea before and after scenting, include strictinin, quercetin-3β-D-glucoside, L-glutathione reduced, methyl anthranilate, ellagic acid, theaflavin 3-gallate and umbelliferone. These compounds play an important role in the formation of the taste quality of jasmine tea. Based on the partial least squares (PLS) analysis of the 7 key non-volatile compounds and taste quality of jasmine tea, the partial least squares regression equation was obtained. The results of repeated experiments show that the equation is reliable and can be used to compare the taste quality of jasmine tea. This study provided a theoretical basis for a comprehensive understanding of the formation of the taste quality of jasmine green tea, and provided a reference for further improving the taste quality of jasmine tea.

To explore the effects of tea light complementary mode on the growth environment, yield performance and economic benefits, the microclimate environment such as temperature, humidity and light in the tea garden-PV complementary model was analyzed in this study with the open-air tea garden as a control. Indicators such as tea bud germination and growth, photosynthetic rate, and fresh leaf yield were detected, and the photovoltaic power generation was simulated and calculated. The overall economic benefits of the tea garden were analyzed. The results show that the photosynthetically active radiation of the tea canopy in photovoltaic tea gardens was lower than that in open-air tea gardens. The average minimum temperature of tea canopy in photovoltaic tea gardens at night in spring (March) was 0.63 ℃ higher than that in open-air tea gardens, and the average maximum temperature in daytime in summer (July) was 1.80 ℃lower than that in open-air tea gardens. The average relative humidity of tea canopy in photovoltaic tea gardens was higher than that in open-air tea gardens. The tea buds in photovoltaic tea gardens germinated and grew faster, and the utilization efficiency of light radiation was higher. The yield per unit area of the picking area in different harvesting seasons was 9.74%-28.84% higher than that of the open-air tea gardens. The overall output of the tea garden decreased by 23.11% to 34.16% due to the occupation of land for the construction of photovoltaic modules. The annual income of photovoltaic tea gardens, including power generation revenue, was 6.030×10⁵ CNY per hectare, while the annual income of open-air tea gardens was 2.249×10⁵ CNY. Considering the one-time investment cost of 3.740 3 million CNY for building photovoltaic modules, the total revenue of photovoltaic tea gardens will exceed that of open-air tea gardens after 9 years. This study has certain guiding and referential significance for the application and promotion of the tea-light complementary agricultural model in southern China.

To investigate the ameliorative effect of matcha on the memory acquisition impairment model mice induced by scopolamine and its underlying mechanisms, C57BL/6 female mice were divided into 6 groups, namely the control group, the scopolamine group, the donepezil group (1.50 mg·kg^-1), the low-dose matcha group (0.75 g·kg^-1), the medium-dose matcha group (1.50 g·kg^-1) and the high-dose matcha group (3.00 g·kg^-1). On the 31st to 35th days after the injection, the memory acquisition impairment model was established by using scopolamine (5.00 mg·kg^-1). The analysis was carried out through methods and techniques such as the Morris water maze test, the step-down test, the dark avoidance experiment, HE staining, enzyme-linked immunosorbent assay (ELISA) and Western blotting. The results demonstrate that matcha could, to a certain extent, improve the learning and memory abilities of the mice with memory acquisition impairment, inhibit the expression of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in the hippocampus tissue, enhance superoxide dismutase (SOD) in the hippocampus tissue, reduce malondialdehyde (MDA) content and glutathione peroxidase (GSH-Px) activity, and upregulate the expressions of Nrf2, SOD, GSH-ST and HO-1 proteins in hippocampal tissue. Meanwhile, it regulated choline metabolism and increased hippocampal choline content, thereby improving the cognitive dysfunction induced by scopolamine in mice. In conclusion, Guizhou-produced matcha plays a positive role in ameliorating memory impairment induced by scopolamine, and its mechanism may be related to enhancing anti-inflammatory activity, alleviating oxidative stress, and regulating neurotransmitters. This study enriched and improved the mechanism of matcha in ameliorating Alzheimer's disease and provided a research foundation and theoretical support for matcha-related health foods.

Tea plant (Camellia sinensis), as a crucial economic crop, faces core challenges in quality improvement through breeding. To address the prolonged traditional breeding cycle (≥2 years) and inefficient phenotypic identification, this study utilized 90 progeny from natural hybridization of a chlorotic cultivar ‘Anjihuangye’, integrating genotypic data from 40 326 core single nucleotide polymorphism (SNP) loci with biennial phenotypic observations (chlorotic∶non-chlorotic = 54∶36). We systematically compared three machine learning models (logistic regression, random forest, and support vector machine) for predictive performance. The results demonstrate that the random forest model achieved the best performance in the 10-fold cross-validation, and its accuracy was 78.96%, which was significantly better than other models (P<0.05). Feature importance analysis identifies two critical genetic markers: Chr8_142477650 (encoding the chloroplast-localized pyruvate dehydrogenase E1 beta subunit) and Chr8_126475215 (involved in RNA processing regulation). However, independent validation using 109 germplasms with diverse yellowing trait reveals that the prediction accuracy of the model decreased to 21.10%, and the feature weight deviations caused by genetic background heterogeneity was the main limiting factor. In this study, a machine learning prediction framework for tea yellowing trait was established, which shortened the phenotypic identification cycle from 24 months to real-time genotype analysis, and realized the prediction of traits in the early stage of breeding. Although cross-cultivar generalizability requires improvement, the developed SNP-phenotype association model provided an extensible paradigm for deciphering genotype-phenotype complexity in tea plants, representing an innovative application of artificial intelligence in predicting complex traits of woody perennials.

Qingzhuan brick tea, as one of China’s characteristic brick-shaped dark tea mainly produced in Xianning city of Hubei Province, is widely favored by consumers for its unique sensory characteristics and health benefits. Focusing on the quality of Qingzhuan brick tea, this paper reviewed its sensory characteristics, main active components and health effects, as well its main influencing factors. It also prospected the future product development and research directions of Qingzhuan brick tea, in order to provide a reference for the diversified development of Qingzhuan brick tea products and personalized precise nutrition research, and promote the development of Qingzhuan brick tea processing and storage technology in the direction of modernization and intelligence.

The effects of different pH and digestive enzymes in tea soup on tea polyphenols (TP), catechins (CATE) and their antioxidant activities were investigated by using an in vitro simulated digestion model, and the differences between dry tea and instant tea powder were compared. The TP concentration was determined by Folin phenol method, and the catechins were quantitatively analyzed by high performance liquid chromatography (HPLC). The antioxidant activities of the two kinds of tea soups were comprehensively evaluated by Ferric reducing ability of plasma (FRAP), 1,1-diphenyl-2-trinitrophenylhydrazine free radical (DPPH) and 2,2ʹ- diazo-bis-3-ethylbenzothiazoline-6-sulfonic acid free radical (ABTS). The results show that the TP concentration (874.19 mg·L^-1) of black instant tea powder before simulated digestion was 1.59 times that of dry tea soup (551.50 mg·L^-1), the cate concentration (239.58 mg·L^-1) was 1.68 times that of dry tea soup (142.98 mg·L^-1), and the antioxidant activity was about twice that of dry tea soup. After gastrointestinal simulated digestion, the stability of tea soup cate and antioxidant activity of black instant tea powder were lower than that of dry tea, which may be related to the high proportion of epigallocatechin gallate (EGCG)+epigallocatechin (EGC) in instant tea soup and its intestinal degradation law. Both pH 2.0 and pH 7.0 decreased the antioxidant activity of tea soup, and the effect of acidic pH was greater. The addition of pepsin, TP and cate increased the antioxidant capacity of tea soup, while the addition of bile salt and trypsin decreased the FRAP value of tea soup. To sum up, the preparation of instant tea powder, pH and the phased action of digestive enzymes could affect the digestion stability of catechins in tea. By optimizing the extraction parameters of instant tea, the changes of catechins in tea can be reduced, and the influence of gastric acid environment during instant tea drinking can be avoided, so as to improve the bioavailability of catechins in tea leaves.

In recent years, multi-arm tea-picking robots have become a research hotspot due to the shortage of labor, rising labor costs, and the demand for high-precision picking in the high-quality tea industry. A collaborative planning method that dynamically allocates the space for picking points was proposed, and the path planning of the robotic arm was optimized by combining the ant colony algorithm and the picking point priority in order to improve the operational efficiency of the tea-picking robot. Simulation results show that the average time for one-shoot picking was 1.41 s, and the time ratio for dual-arm synchronous operation was 91.95%. Compared to the 62.86% coverage rate of the two-space segmentation method, this method achieved full coverage of the space. To overcome the limitations of the existing independent operation mode of the depth camera, a dynamic addition of picking point planning was further proposed, which realized the synchronous operation of the depth camera and the robotic arm. Field experiment results show that the tea-picking robot adopts the picking point allocation method that dynamically divides the operating space and the double-arm collaborative planning method that dynamically divides the space for picking point allocation. The average time for one-shoot picking was 1.52 s, a 29.95% improvement compared to the one-arm tea-picking robot. This method not only significantly improves the operational efficiency of the tea-picking robot but also achieves full coverage of the space, ensuring efficient collaborative picking.

To investigate the dynamic changes of the characteristic aroma of Xinyang Maojian during processing and the impact of water treatment processes on its aroma, this study took Xinyang Maojian tea made from the tea cultivar ‘Xinyang 10’ as the research object. The aroma components and their relative contents in samples of different stages, including fresh leaves, fixation, rehumidification, rolling, shaping, and drying, using both water treatment and traditional methods, were identified and analyzed using headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) technology. The results show that a total of 81 volatile metabolites were identified in the experimental samples, among which high contents of esters, terpenes, and heterocyclic compounds were found in Xinyang Maojian and they were considered as the main aroma-contributing substances. After fresh leaves were treated with water, the contents of volatile components decreased rapidly, and then tended to be stable in each processing stage. Compared with the traditional process, there were 7 volatile components with significant differences in the aroma components of the finished tea processed by water treatment, among which 4 volatile components had higher relative odor activity value (ROAV) in the water treatment samples than in the traditional process. This study deeply analyzed the dynamic changes of aroma components during the Xinyang Maojian processing and the impact of water treatment technology on its aroma. This paper provided a scientific basis for the quality improvement of Xinyang Maojian and the application of water treatment technology.

To clarify the occurrence species of Helopeltis, which is an important tropical economic pest in tea gardens of China, a total of 1 710 samples of Helopeltis adults were collected from 14 tea gardens in Hainan, Guangdong, Guangxi and Yunnan provinces. The collected bugs were reared in laboratory, and the morphology of eggs, nymphs and adults were observed. Three species were identified, including H. theivora Waterhouse, H. cinchonae Mann, and H. fasciaticollis Poppius. H. cinchonae was first found in tea gardens of China, H. cinchonae and H. theivora were the main species of Helopeltis in tea gardens of China. Damage characteristics of the three species on tea plants were similar. The three species could be distinguished based on the color of body and the antennae of males. The research shows that there were at least 3 species of Helopeltis in tea gardens of China.

Anthocyanins exhibit diverse health benefits in humans, including antioxidant and anticancer effects, making them a key target for functional crop breeding. Anthocyanin synthase (ANS), a pivotal enzyme in anthocyanin biosynthesis, has been demonstrated to regulate anthocyanin accumulation in various crops. However, functional studies on ANS genes in tea plants (Camellia sinensis) remain limited. In this study, we identified a specifically highly expressed CsANS1 gene in the purple leaves of tea cultivar ‘Zijuan' through comparative transcriptome analysis of four tea cultivars with distinct leaf colors. Gene expression analysis reveals that CsANS1 expression in ‘Zijuan' was significantly higher than in other cultivars and other ANS family members (CsANS2 and CsANS3) in tea plants. Tissue-specific expression analysis further demonstrats that CsANS1 exhibited the highest expression level in ‘Zijuan' leaves, showing an expression trend of first increasing and then decreasing with the development of buds and leaves. Phylogenetic analysis indicats that sequence similarity among ANS gene copies within species is higher than that among interspecies homologs, and all members of the tea ANS family possess the highly conserved Fe(Ⅱ)/2OG dioxygenase domain. Comparative gene sequencing and protein tertiary structure prediction analyses reveal two non-synonymous mutations in the coding region of CsANS1 in ‘Zijuan', with the amino acid variation at position 165 potentially affecting local protein conformation. Following VIGS-mediated silencing of CsANS1, the anthocyanin content in ‘Zijuan' shoots significantly decreased, accompanied by a lightening of leaf color. In conclusion, this study confirms that CsANS1 is a key gene regulating high-level anthocyanin accumulation in ‘Zijuan' buds and leaves, providing an important molecular target for breeding high-anthocyanin tea cultivars.

To reduce the time cost of repeatedly constructing data samples of tea buds from different seasons and regions, and to improve the accuracy and generalization ability of deep learning models in identifying different tea buds, this paper proposed a small-sample tea bud recognition model based on deep transfer learning, named QY-Yolov7-Tea. By incorporating transfer learning techniques into deep learning, a source domain bud detection model based on Yolov7 was used to obtain pre-trained weights. The model's backbone, neck and detection head are then fine-tuned and frozen, with experiments conducted on different target samples based on the pre-trained weights. The final result is a transfer learning model for tea buds. Experimental results show that, compared with the traditional Yolov7 bud detection model, the deep transfer learning model improves the mean average precision for recognizing tea buds from different seasons and regions by 8.8 percentage points and 15.4 percentage points, respectively, significantly enhancing the model's robustness and recognition capability, and effectively addressing the issue of insufficient training samples.

With the increasing demand for jasmine tea in the market, new requirements have been set for the efficiency of the scenting process and the labor costs. This study analyzed the aroma enhancement effect and influencing factors of jasmine hydrosol on the scenting jasmine tea, and explored the feasibility of using scenting in the rapid scenting process of flower tea, based on sensory evaluation, dynamic headspace adsorption and micro-chamber/thermal extractor-thermal desorption-gas chromatography-mass spectrometry/flame ionization detector (μCTE-TD-GC-MS/FID) and other methods. The sensory evaluation results indicate that scenting can effectively enhance the floral intensity of green tea, but the aroma enhancement effect on Fuding white tea is not significant. The study used gas chromatography-olfactometry (GC-O) to identify 18 key odorant compounds in jasmine hydrosol and employed μCTE-TD-GC-MS/FID to quantitatively analyze the contents of these key odorant compounds in tea samples after scenting. The results show that the floral intensity after scenting was influenced by factors such as raw material type, tenderness and form. Under single scenting conditions, the scent absorption capacities of the four green teas were better than Fuding white tea, with the average increase of olfactory compounds in green tea being 5.83 mg·kg^-1, which was 2.5 times the increase in white tea. Additionally, lower-grade tea materials exhibit better adsorption capacities than higher-grade materials. For instance, the aroma increase in Huangshan maofeng second-grade tea material was 7.41 mg·kg^-1, which was 1.5 times that of its special-grade counterpart. Therefore, materials with medium or slightly lower tenderness can achieve the same aroma enhancement effect as higher-grade materials with less hydrosol scenting. The findings of this study demonstrate that rapid scenting with jasmine hydrosol is also a feasible and effective technical option for the future.

The parallel mutation of tea stems and leaves is a new type of mutation, which is a high-quality material for developing bud tea, special tea products and edible and ornamental tea. Therefore, studying the causes of parallel variation in tea plants and mining its key control genes can provide new targets for the current diversified needs of tea breeding. In this study, the mutant stems and leaves were used as the research materials, and the normal stems and leaves were used as the control. The paraffin section method was used to observe the tissue structure, and the transcriptome sequencing technology and WGCNA analysis technology were used to excavate the key genes of the parallel phenomenon of stems and leaves in tea plants. The observation results of tissue structure show that parallel variation could not only increase the number of tea buds and yield, but also effectively increase the area and number of vessels in stems and leaves of tea plants, and improve the photosynthetic capacity and stress resistance of tea plants. The transcriptome sequencing study shows that the differential genes were mainly enriched in the two pathways: ABC transporters and plant-pathogen interaction, and 9 key genes were analyzed and mined. A total of 26 co-expression modules were identified by WGCNA, two trait-related specific modules were mined, and 8 core genes were screened. These 17 key genes are regulated in three forms: ABCB (ATP binding cassette subfamily B) and ABCC (ATP binding cassette subfamily C) families, RAC3 (RAC family small GTPase3), and FKBP (FK506-binding proteins). These genes are mainly involved in auxin and cell division. Genes such as ABCG34 (ATP binding cassette subfamily G34), CDPK2 (Calcium-dependent protein kina2), KCS2 (β-ketoacyl-CoA synthase2), LAC11 (Laccase11), EP1 (Epidermis-specific secreted glycoprotein1) and LTP (Lipid transfer protein) are involved in the biosynthesis of cellulose, lignin and pectin in the cell wall of tea plants, and regulate cell morphogenesis by regulating the synthesis and extension direction of cell wall, so as to realize the parallel differentiation of tea stems and leaf veins. Dimethylmenaquinone methyltransferase and histone-lysine N-methyltransferase regulate gene expression through DNA methylation, which eventually leads to the occurrence of the apparent morphology of parallel connection between tea stems and leaves.

To investigate the effect of pile-fermentation of Liupao tea on the structural characteristics and antioxidant capacities of oligosaccharides, the same batch of the raw tea and Liupao tea after fermentation were selected in this study. The raw tea oligosaccharide RLTO-1 and the oligosaccharide ALTO-2 of Liupao tea after fermentation were separated and purified by water extraction and alcohol precipitation, macroporous adsorption resin and dextran gel LH-20 column. The chemical composition was analyzed by chemical analysis, gel penetration chromatography, ion exchange chromatography, infrared spectroscopy and UV visible spectrophotometer. The differences in in vitro antioxidant capacities of oligosaccharides before and after fermentation were evaluated by measuring their ABTS radical scavenging capacity, DPPH radical scavenging capacity and total antioxidant capacity. The results show that the total sugar contents of RLTO-1 and ALTO-2 were 57.30% and 63.98%, and the polyphenol contents were 11.77% and 22.28%, respectively. The contents of uronic acid were 3.49% and 18.25%, respectively. RLTO-1 contains two components with molecular weights of 1 565 Da and 607 Da, primarily composed of glucose, arabinose, ribose and other monosaccharides. ALTO-2 has a molecular weight of 833 Da and is mainly composed of monosaccharides such as rhamnose, arabinose, galactose, glucose, mannose, and galacturonic acid. RLTO-1 is a class of hetero-oligosaccharide with α and β configurations and non-reducing pyran rings, and ALTO-2 is a hetero-oligosaccharide with a non-reducing pyran ring with a α-configuration. The results of in vitro antioxidant studies show that the oligosaccharides before and after fermentation had antioxidant activity, and ALTO-2 shows better antioxidant capacity compared with RLTO-1. This indicates that the molecular weight, monosaccharide composition and structure of Liupao tea oligosaccharides are significantly changed after heap fermentation, and have stronger antioxidant activities, which provide a theoretical basis for the development of Liupao tea oligosaccharides.

To investigate the effects of geographical origin and cultivar on green tea quality, this study analyzed the liquor color, physicochemical components, and in vitro antioxidant activities of eight green teas from Longnan, Gansu and Jinhua, Zhejiang. Correlation and cluster analyses were employed for a comprehensive evaluation. The results show that compared to Longnan green teas, Jinhua green teas exhibited brighter green liquor color and a fresher, sweeter aftertaste. In contrast, Longnan green teas contained higher levels of tea polyphenols, flavonoids, caffeine, vitamin C (VC), catechins, and mineral elements, as well as superior in vitro antioxidant activities, including DPPH radical scavenging ability, ABTS radical scavenging ability, hydroxyl radical (·OH) scavenging ability, and total antioxidant ability (T-AOC). Among the tested cultivars, Longnan Camellia sinensis cv. ‘Yunfeng 5' and Jinhua Camellia sinensis cv. ‘Jiaming 1' had the best overall quality and antioxidant performance. The correlation results show that the color, physical and chemical components and antioxidant capacity of tea decoction were closely correlated. Among them, tea polyphenols, VC and epigallocatechin gallate (EGCG) were positively correlated with the antioxidant ability of the four kinds of tea decoction (P<0.01). Cluster analysis divided the samples into two distinct groups corresponding to their geographical origins, indicating that origin had a greater influence on tea quality than cultivar. This study provided a theoretical foundation for evaluating the effects of geographical origin and cultivar on the antioxidant properties of green tea.

Ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was used to analyze the contents and composition of 10 α-dicarbonyl compounds in tea by detecting stable quinoxaline derivatives formed by reactions between α-dicarbonyl compounds and o-phenylenediamine. The results demonstrate that 3-deoxyglucosone was the predominant dicarbonyl compound in all six major tea categories. The high-temperature de-enzyming process was identified as the primary driver for the formation of short-chain α-dicarbonyl compounds in green tea, yellow tea and oolong tea. While relatively lower drying temperatures significantly influenced the formation of long-chain α-dicarbonyl compounds in white tea and dark tea. The total contents of α-dicarbonyl compounds in green tea, yellow tea, black tea and oolong tea exhibited an increasing trend with the oxidation degree of catechins. Additionally, the absence of rolling during white tea processing and microbial activity during the pile-fermentation process of dark tea were critical factors for the accumulation of α-dicarbonyl compounds.

‘Huangjincha’ is a tradtional and local tea germplasm resource in Xiangxi, with an excellent flavor quality, especially its obvious aroma characteristics, which is highly favored by consumers. This study selected four tea cultivars, namely ‘Baojing Huangjincha 1’, ‘Huangjincha 2’, ‘Huangjincha 8’, ‘Huangjincha 18’, to produce ‘Huangjincha’ green and black tea samples. Sensory evaluation, gas chromatography-mass spectrometry (GC-MS), and relative odor activity value (ROAV) were used to analyze their aroma components. The results show that ‘Huangjincha’ green tea is characterized by its fresh and elegant aroma and a refreshing, sweet aftertaste, while ‘Huangjincha’ black tea exhibits distinct sweet and floral notes. A total of 101 volatile aroma compounds were detected in ‘Huangjincha’ green tea. Among these, esters and alcohols accounted for 34.4% to 53.5% and 21.9% to 36.3%, respectively. A total of 140 volatile aroma compounds were detected in ‘Huangjincha’ black tea, with alcohols, esters, and aldehydes being the main volatile components, accounting for 38.6% to 60.0%, 11.0% to 26.9%, and 9.7% to 17.8%, respectively. The primary aroma-contributing compounds of both ‘Huangjincha’ green and black tea were further screened. A total of 20 compounds were identified as key contributors to the aroma of ‘Huangjincha’ green tea, including linalool, 3,5-octadien-2-one, cis-jasmone, β-ionone, lauric acid, β-cyclocitral, and 2-pentylfuran. For ‘Huangjincha’ black tea, 33 shared key aroma components compounds were identified, including linalool, benzaldehyde, 3,5-octadien-2-one, trans-β-ionone, (Z)-linalool oxide (furanoid) and 4-heptenal. This study had preliminarily revealed the similarities and differences in aroma quality characteristics and chemical composition in ‘Huangjincha’ green and black tea made by different cultivars, which could be used to improve the processing technology system of ‘Huangjincha’.

Tea hairs are an important indicator for evaluating the appearance quality of black tea. Currently, the evaluation mainly relies on the sensory assessment of professionals, which is highly subjective and abstract, lacking objective and digital quality evaluation methods. To construct a digital evaluation method for the quality of tea hairs, this study collected images of Qimen black tea samples with three different tea hairs quality grades. The HSV color image segmentation technique was used to extract the HSV color space component features of the region of interest (ROI), and a segmentation index (SI) was constructed to retrieve the optimal segmentation thresholds for tea hairs, tea body, and shadows. The image segmentation effect was qualitatively and quantitatively evaluated using the masking method and pixel point discrimination, and a quantification method for the proportion of tea hairs was established. The results show that the average segmentation accuracy of tea hairs, tea body, and shadow areas reached 98.70%. Furthermore, through the quantification of the proportion of tea hairs, the recommended hairs proportion thresholds for the three tea hairs quality grades of Qimen black tea (“Prominent golden hairs”, “Observable hairs”, and “Less hairs”) were obtained. The linear regression analysis of different hairs gradient blended tea samples (R²=0.958, P<0.01) and the generalization application effects on ‘Dianhong’ and ‘Jinjunmei’ indicate that the digital evaluation method of tea hairs quality constructed in this study has good adaptability in different hairs quantity intervals and different black tea categories.

To elucidate the quality characteristics of Yihong black tea, a systematic analysis was conducted on the quality attributes of Yihong black tea with different levels of tenderness based on sensory evaluation, colorimetric analysis, and targeted metabolomics. The results demonstrate that sensory evaluation scores exhibited a positive correlation with leaf tenderness. The theaflavin content exhibited an initial increase followed by a decline with the decrease in leaf tenderness, and the content of theaflavins was positively correlated with the color parameter L^* value of the tea infusion. The soluble sugar content elevated with the decrease in leaf tenderness, whereas the contents of tea polyphenols and total free amino acids gradually declined. Furthermore, a total of 162 non-volatile metabolites were identified based on the UPLC-MS/MS. Among them, 24 characteristic metabolites were characterized as marker compounds for distinguishing Yihong black tea with different levels of tenderness, including 10 flavonoids [hyperoside, kaempferol-3-O-(6''-trans-P-coumaroyl-2''-glucosyl) rhamnoside, quercetin 3-rutinoside-7-glucoside, keracyanin, kaempferol 3-rutinosidea, astragaline, kaempferol 3-O-galactoside, quercetin 3-rutinoside-7-galactoside, quercetin 3-O-rhamnoside-7-O-glucoside, quercetin 3-rutinoside], 7 catechins [(+)-catechin, catechin gallate, epicatechin, (-)-epigallocatechin, (-)-gallocatechin gallate, epigallocatechin gallate, (-)-epicatechin gallate], 4 amino acids [L-phenylalanine, L-arginine, D-(+)-pipecolinic acid, L-(-)-pipecolinic acid], 3 alkaloids [caffeine, theobromine, adenosine]. These results clearly defined the typical quality attributes of Yihong black tea as “amber-hued liquor, and a honeyed fruity bouquet” and further elucidated the characteristic metabolites responsible for the quality differences in Yihong black tea with different levels of tenderness, providing a scientific basis for optimizing processing techniques and precisely modulating flavor profiles, and facilitating standardized processing and quality enhancement of Yihong black tea.

In order to improve the droplet deposition distribution and enhance the control effect, the operational parameters (spray droplet size, flight height, flight speed and spray volume) of a four-multirotor plant protection unmanned aerial vehicle (EA-30X) were optimized in tea gardens. The results show that the spray droplet size, flight height, flight speed and spray volume could significantly affect the droplet deposition distribution in the tea canopy. With the increase of spray droplet size, the droplet coverage and volume median diameter in the surface and inner layers of the tea canopy could be significantly increased. When the spray droplet size was 100 µm, the droplet coverage in the surface and inner layers of the tea canopy was 2.58 and 3.49 times higher than that of 20 µm, respectively. Similarly, the spray volume also significantly increased the droplet coverage and droplet size in the surface and inner layers of the tea canopy. When the spray volume increased from 30 L·hm^-2 to 90 L·hm^-2, the droplet coverage in the surface and inner layers of the tea canopy were maximally increased by 151% and 141%, respectively. Moreover, the coverage of the surface and inner layers of the canopy could be significantly decreased with the increase of flight height and flight speed. When the flight height reduced from 5 m to 2 m, the maximum increase of the coverage of the surface and inner layers were 45% and 173%, respectively. When the flight speed decreased from 5 m·s^-1 to 2 m·s^-1, the maximum increase of the coverage of the surface and inner layers were 84% and 252%, respectively. Overall, under the premise of ensuring operational safety and efficiency, reducing the flight height and flight speed and increasing the spray volume can significantly improve the coverage of droplets in the surface layer of the tea canopy. The operational parameters of EA-30X in tea gardens were proposed as the spray droplet size of 100 µm, flight height of 2 m, flight speed of 2 m·s^-1, spray volume of 90 L·hm^-2.

To investigate the metabolic response mechanisms of tea plants with different resistance levels at the early stage of infestation by the tea orange mite (Acaphylla theae), this study used the mite-resistant cultivar ‘Meizhan’ and the mite-susceptible cultivar ‘Fuyun 6’ as materials to analyze the metabolomic changes 24 hours after mite infestation. Ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) combined with physiological and biochemical index measurements was employed to compare differences in secondary metabolites between the two cultivars (screening criteria: VIP>1 and P≤0.05). The results show that under mite stress, the total phenolic and flavonoid contents in the resistant cultivar were significantly higher than those in the susceptible cultivar, while the amino acid and free fatty acid contents were significantly lower. Metabolomic analysis identified 370 significantly differential metabolites, primarily involving flavonoids, alkaloids and lipids. KEGG pathway enrichment analysis reveals that the differential metabolites were significantly enriched in the flavonoid and flavonol biosynthetic pathways, with key flavonoids such as naringenin, quercetin, myricetin, and apigenin accumulating significantly in the resistant cultivar. In conclusion, early infestation by the tea orange mite induces the activation of flavonoid metabolic pathways in tea plants, and the resistant cultivar enhances the synthesis of secondary metabolites such as naringenin and quercetin, forming a distinct defense response mechanism from that of the susceptible cultivar. This study provided a theoretical basis for elucidating the molecular mechanisms of mite resistance in tea plants and for breeding resistant cultivars.

In order to establish a high performance liquid chromatographic (HPLC) method for the analysis of anthocyanin-like substances in tea, six typical anthocyanins (delphinidin, cyanidin, petunidin chloride, pelargonidin, paeonidin and malvidin) were used as the targets, and Cosmosil 5C₁₈-AR-Ⅱ chromatographic column (250 mm×4.6 mm, 5 μm) was used with the mobile phases of 0.5% formic acid in water and 100% acetonitrile as mobile phases A and B, respectively. The column temperature was 35 ℃, the flow rate was 0.8 mL·min^-1, the detection wavelength was 525 nm, and the injection volume was 20 μL. Under the analytical conditions, the anthocyanin components were well separated. In a certain range, the linear relationship was significant, and the correlation coefficient square (R²) was above 0.999 0. The relative standard deviations (RSD) of the repeatability, precision and stability tests were in the range of 1.20%-1.40%, 1.15%-2.12% and 1.35%-3.38%, respectively. The results of the spiked recovery test show that the average recoveries of the anthocyanin components were in the range of 86.08%-110.34% with an RSD between 0.24% and 6.13%. The method has good reproducibility, precision and stability, and can detect the contents of anthocyanin-like substances in tea.

Codon usage bias serves as a critical driving mechanism in gene expression regulation and molecular evolution, holding significant biological importance in the evolution of organelle genomes in plants. This study focused on the economically important tea cultivar ‘Baihaozao’ (Camellia sinensis cv. ‘Baihaozao’) and systematically analyzed the codon usage patterns and evolutionary drivers of its chloroplast (52 genes) and mitochondrial (29 genes) genomes for the first time. The results indicate: (1) the average effective codon number (ENC=44.57±4.59) of the chloroplast genome is significantly lower than that of the mitochondrial genome (ENC=51.87±5.31), with both exhibiting weak preference characteristics. Neutrality analysis reveals that the chloroplast's preference is primarily driven by natural selection (correlation between GC_3s and ENC, R² =-0.016), whereas the mitochondrial genome is regulated by a combination of natural selection and mutational pressure (R² = -0.11), which is consistent with the evolutionary constraints observed in the organelle genomes of dicotyledons. (2) RSCU analysis shows that both types of organelle genomes significantly prefer synonymous codons ending in A/U, with high-expression chloroplast genes (e.g., ndhA, rps14) exhibiting a stronger preference for A/U terminal codons. This suggests that translational selection optimizes highly expressed genes. (3) Through multivariate statistical screening, 18 optimal codons were identified for the chloroplast genome (e.g., GCA, GCU) and 18 optimal codons for the mitochondrial genome (e.g., GCA, AGA). GCA was favored in both organelle types, reflecting the adaptive convergence of functional genes across organelles. This study elucidated the heterogeneity of codon usage characteristics in the organelle genomes of ‘Baihaozao’ and their evolutionary drivers for the first time, providing a theoretical basis for the adaptive optimization of exogenous genes and the construction of cross-organelle expression regulatory networks in molecular tea breeding.

Processing techniques significantly alter the accumulation and composition of internal components in tea, forming different categories of tea products. Currently, there is limited research on the accumulation of compounds in different categories of Jingshan tea and their impact on taste quality characteristics. In this study, Jingshan green tea, matcha, and black tea were selected as the research object. The contents of physicochemical components such as water extracts, tea polyphenols, amino acids, and caffeine were detected, and the main compounds that constitute the taste and aroma skeleton of Jingshan tea were analyzed. The results show that the contents of compounds related to taste, such as water extracts, tea polyphenols, theanine, and glutamic acid, were significantly higher in green tea than in black tea. Meanwhile, black tea exhibited the highest accumulation of γ-aminobutyric acid. Jingshan green tea, matcha, and black tea were characterized by their “rich floral aroma and refreshing sweetness”, “fresh and thick”, and “sweet fruit aroma and lingering sweetness”, respectively. A total of 101 volatile compounds were identified in different categories of tea samples (31 in green tea, 30 in matcha, and 40 in black tea), among which cis-jasmone and 4,8-dimethyl-1,3,7-nonatriene are the key components contributing to the “elegant and floral” aroma quality of green tea. β-ionone, α-ionone, and β-cyclocitral are the essential components for the “fragrance” aroma of matcha. Geraniol and methyl salicylate are the crucial components for the “sweet aroma” of black tea. The research findings would be beneficial for expanding the study of Jingshan tea's flavor chemistry and provided a valuable reference for enhancing the high-quality processing of Jingshan tea.

Tea is a cash crop with large cultivated area in China, and its growth and development mechanism are strictly regulated by genes related to biological clock. In this study, the CsLUX gene was cloned using cDNA from tea cultivar ‘Longjing 43’ as template and sequence alignment and phylogenetic analysis were performed. Within two photoperiodic periods (48 h), the relative expression of CsLUX gene was detected by RT-qPCR, and photosynthetic parameters, stomatal opening and chlorophyll contents in tea leaves were also determined. The total length of CsLUX gene is 951 bp, encoding a hydrophilic protein composed of 316 amino acids. The secondary structure is mainly composed of α-helix and random curling. CsLUX is closely related to CCA1, ELF3 and other key components of the biological clock. The variation trend of photosynthetic parameters in tea leaves at different time points was basically consistent with stomatal opening, and the value of chlorophyll SPAD was basically stable. The relative expression of CsLUX reached its peak under dark conditions and maintained a low expression level during the day in response to changes in circadian rhythm. The expression of CsLUX gene was correlated with the rhythmic changes of photosynthetic parameters in two photoperiodic periods (48 h) in tea plants.

This study systematically investigated the molecular characteristics, expression patterns of the vitellogenin (Vg) gene EonuVg, and its response to imidacloprid in Empoasca onukii. The full-length cDNA sequences of two EonuVg genes, EonuVg1 (PP128347) and EonuVg2 (PP128348) were cloned and designated. Their open reading frames (ORFs) are 6 066 bp and 6 138 bp, encoding 2 021 and 2 045 amino acids, respectively. Both proteins contain conserved structural domains of Vg, including a signal peptide, Vitellogenin-N superfamily (Vit-N), Vit_open_b-sht (Vit-b) and Von Willebrand factor type D (VWD) domains, along with insect-specific motifs such as N-terminal poly-serine tracts, an RNPR cleavage site, a GLCG conserved motif, and C-terminal cysteine residues. The RT-qPCR results show that EonuVg1 and EonuVg2 exhibited low expressions during the early developmental stages (eggs and nymphs), and their expression peaks appreared in the newly emerged female adults. Tissue-specific expression analysis shows that the two genes were highly expressed in the ovary and fat body. After silencing the two genes by RNAi technology, the female duration, oviposition duration and oviposition quantity show a downward trend, but there was no significant difference compared with the control group feeding with dsGFP. The results of imidacloprid stress experiment show that sublethal and higher concentrations of imidacloprid significantly downregulated the expressions of EonuVg1 and EonuVg2 in female adults. This study preliminarily discussed the possible function of EonuVgs in the development and their response to imidacloprid in E. onukii, which provided theoretical basis and data support for further study on the function of Vg genes.

Tea plants [Camellia sinensis (L.) O. Kuntze] is important leaf cash crops in China, and its growth and development are affected by plant hormones. As one of the six classical plant hormones, brassinosteroids (BRs) play crucial roles in regulating both developmental processes and stress adaptation in tea plants. Steroid 5α-reductase is a key enzyme in the brassinosteroid biosynthesis pathway. To characterize steroid 5α-reductase in Camellia sinensis, the CsDET2 gene was cloned from tea cultivar ‘Shuchazao'. Then, the physicochemical properties, secondary and tertiary structures, sequence characteristics, phylogenetic relationships, and subcellular localization of the encoded protein were analyzed, along with the cis-acting elements in gene promoter region. Furthermore, the expression profile of CsDET2 was examined across different organs under abiotic stress conditions and during a 12 h/12 h photoperiod cycle. The results reveal that the CsDET2 gene contains a 783 bp open reading frame encoding 260 amino acids. The CsDET2 protein has a molecular weight of 30 158.97 Da with a theoretical isoelectric point of 9.28, and is predominantly composed of α-helices and random coils, containing a characteristic steroid dehydrogenase domain. Comparative sequence alignment with DET2 proteins from 15 species shows 78.25% amino acid sequence identity. Phylogenetic analysis suggests that CsDET2 shares the closest evolutionary relationship with AfDET2 from Actinidiarufa. Subcellular localization experiments confirm that CsDET2 is localized in the cytoplasm. Analysis of cis-acting elements reveals that the promoter region of CsDET2 contains 4 types of photo-responsive elements, 4 types of stress-responsive elements, 3 types of hormone responsive elements, and 5 types of transcription factor binding sites. The fluorescence quantification results show that CsDET2 was expressed in all organs, and the expression level was the highest in the old leaves. In the 12L/12D photoperiod, the expression level of CsDET2 decreased first and then increased during the daytime, increased first and then decreased at night, and the expression level of CsDET2 at night was higher than that during the daytime. The expression of CsDET2 shows significant changes under high temperature and salt stress treatments, and was regulated by exogenous gibberellins. The results provided a theoretical basis and valuable insights for further exploring the function of tea plant steroid 5α-reductase.

Camellia sinensis var. pubilimba ‘Mayu’ is a dominant tea cultivar in Lüchun County, Yunnan. This study systematically analyzed the leaf anatomical structures and biochemical components of 28 germplasms using C. sinensis var. sinensis (CSS) and C. sinensis var. assamica (CSA) as controls. This study established a comprehensive evaluation system for germplasm resources for the first time. Key findings include: (1) M4 and M5 in the ‘Mayu’ tea group (MY) exhibits higher stomatal density than the controls, with a 30.0% and 10.6% reduction in stomatal area relative to CSS and CSA, respectively. The MY group exhibits unique undulated wax layers in the upper epidermis. (2) Cold resistance evaluation via membership function analysis identifies M4 and M5 germplasms with the highest scores (0.975 and 0.689), while the palisade-to-spongy tissue ratio shows a significant positive influence on the cold resistance (β=0.179, P<0.01). (3) Biochemical profiling reveals high stability in ‘Mayu’ tea’s water extracts (46.8%) and tea polyphenols (32.14%) (coefficient of variation, CV<5%). Its phenolic-to-amino acid ratio (9.05-14.54) indicates suitability for both black and green tea processing. The catechin quality index of ‘Mayu’ tea significantly surpassed controls (P<0.05), with bitter amino acids reduced by 18.04% compared to CSS and umami amino acids increased by 17.76% relative to CSA. While sweet amino acids show no significant inter-varietal differences. (4) Ten characteristic markers (including methionine, theanine, caffeine, and seven catechin derivatives) were identified through principal component analysis combined with differential metabolite screening, enabling discrimination of ‘Mayu’ tea from controls. This study elucidated the germplasm specificity of ‘Mayu’ tea from structural adaptation and biochemical perspectives, providing a theoretical foundation for its conservation, breeding, and functional component development.

In this paper, an analytical method for the simultaneous determination of 20 phthalate esters in tea fresh leaves was developed by gas chromatography-tandem mass spectrometry (GC-MS/MS). The phthalate esters in tea fresh leaves were extracted by 0.1% acetonitrile acetate, salted out with sodium chloride, cleaned up with a florisil solid phase extraction column, resolved with acetonitrile, separated by temperature programmed chromatography, monitored with multiple reaction monitoring (MRM) mode, and quantified by the external standard method. Through the optimization of sample extraction, purification and chromatographic conditions, good linearity of the target compounds was obtained in the concentration range of 0.010-2.0 mg·kg^-1 with the corresponding coefficient of determination R²>0.995 5. The average recoveries ranged from 70% to 118% at the three spiked levels of 0.010 mg·kg^-1, 0.10 mg·kg^-1 and 1.0 mg·kg^-1, with the relative standard deviations (RSDs) of <17.8%. The limits of quantification were 0.010~0.050 mg·kg^-1. The method is stable and reliable, and it can meet the needs of the determination of phthalate acid esters in tea fresh leaves.

Milled tea is the raw material for the production of matcha and it is the most important factor in ensuring the quality of matcha. Rapid and effective sorting of milled tea improves its quality. Due to the low efficiency and high labor intensity of the current sorting process in milled tea production, an online sorting system for milled tea was developed in this study. This system is composed of a material conveying system, an image acquisition system, an image recognition system, a positioning system and a sorting execution control system. The image acquisition system is used to collect the milled tea image and make the milled tea image data set. According to the real-time and lightweight requirements of milled tea recognition, the EfficientNet backbone network and SimSPPF module were introduced based on the YOLOv5s model, and the YOLOv5s-EfficientNet-SimSPPF model was improved and designed. On the basis of ensuring the recognition precision, the model recognition speed was improved and the model size was reduced. The established test set was used to evaluate the recognition performance of YOLOv5s, YOLOv5s-EfficientNet, YOLOv5s-SimSPPF and YOLOv5s-EfficientNet-SimSPPF on the PC. The recognition precision, recall, mAP@0.5, inference time and model size of YOLOv5s-EfficientNet-SimSPPF were 0.993, 0.981, 0.995, 6.3 ms and 2.85 MB, respectively. This study also proposed a sorting control algorithm for online sorting based on the online recognition results of milled tea. In addition, an auxiliary algorithm was proposed to prevent low-precision secondary recognition and secondary positioning of the milled tea on the boundary of the field of view of the industrial camera during the sorting process. The YOLOv5s-EfficientNet-SimSPPF model was deployed to the edge device Jetson Nano B01, and the model was tested using the test set. The recognition precision and speed were 0.982 ms and 37.5 ms, respectively. The results show that the real-time milled tea recognition can essentially be achieved by deploying the model migration to the developed online milled tea sorting system. Finally, the milled tea separation was carried out on the designed and developed platform, and the average separation accuracy rate of mixed milled tea leaves and milled tea stems reached 97.0%. The online milled tea sorting system proposed in this paper can meet the actual needs of online milled tea sorting, and can be used as an effective tool for the fine processing of matcha and milled tea sorting operation, providing a reference for online recognition and continuous sorting of other agricultural products.

To explore the differences in tea leaf quality and metabolic profiles of a new seed-leaf dual-pupose tea cultivar ‘Jincha 1' under different cultivation patterns, the study investigated the phenological stages, lengths, weight per hundred buds of single bud, one bud with one leaf, and one bud with two leaves shoots under single plant sparse planting pattern and strip dense planting pattern. Moreover, comprehensive analyses were conducted on quality components and metabolomic profiling of the samples of one bud with two leaves. The results show that the tea cultivar ‘Jincha 1' under single plant sparse planting pattern yielded longer and heavier single buds, one bud with one leaf, and one bud with two leaves shoots compared to the strip dense planting pattern. Additionally, there is a delayed maturity period single plant sparse planting. Furthermore, the contents of tea polyphenols, catechins and gallic acid in the new shoots of single plant sparse planting pattern were 3.96, 5.06, and 1.19 percentage points higher than those of strip dense planting pattern, respectively. Conversely, strip dense planting resulted in higher total amino acid (1.27 percentage points) and theanine (0.21 percentage points) contents. A total of 163 significantly differential metabolites were identified by comparative metabolomics analysis, which were largely enriched in amino acid and polyphenol biosynthetic pathways. Notably, the contents of abscisic acid (ABA), gibberellin (GA), and jasmonic acid (JA) were higher in the single plant sparse planting pattern than those in the strip dense planting pattern. While, the levels of indoleacetic acid (IAA), 6-chloroadenosine phosphate (6-KT), and indole-3-butyric acid (IBA) in the single plant sparse planting pattern were lower than those in the strip dense planting pattern. This study reveals the mechanism by which different cultivation modes affect the tea quality through the regulation of endogenous hormones and metabolic pathways, providing a practical model for efficient cultivation in industrial promotion.

The color values of 865 colored tea germplasm were obtained by comparing them with the PANTONE and RHS plant color cards, and describing them in language. Based on the principles of color science and the descriptors and data standard for tea germplasm, the basis and method for leaf color identification and classification were established according to the coloring regularity of tea leaves. On the basis of the definition of leaf color, a framework of tea leaf color composition consisting of type, series, sub-series and color level was established. The existing tea leaf colors were drawn into a tea leaf color system diagram (leaf color wheel), including 5 types, 9 color series, 6 sub-series (belonging to 3 color series) and 72 color levels. This paper provided a scientific basis for the leaf color differentiation and accurate identification of colored tea germplasms.

Methylated catechins exhibit significant physiological activities, such as anti-allergy effects, and demonstrate stronger stability and higher oral absorption rate than unmethylated catechins. However, tea germplasms rich in methylated catechins are relatively rare. This study measured the EGCG3′′Me content in 447 tea germplasms from different regions with extensive genetic backgrounds, and two unique tea germplasms with high EGCG3′′Me content, namely ‘Jinxiu 2-2’ (JX) and ‘Pinming Tea’ (PM), were found. The tea germplasms JX, PM, and ‘Hongfugui’ (BFK) with high EGCG3′′Me content, as well as ‘Shuchazao’ (SCZ) with EGCG3′′Me content below the detection limit, were used as research materials. Relative expression levels of flavonol and anthocyanin O-methyltransferase (CsFAOMT1) in JX, PM, and BFK were significantly higher than that in SCZ. Further analysis reveals that four types of CsFAOMT1 alleles were cloned from the four tea germplasms, and all of them contain CsFAOMT1.3. Enzyme activity analysis at the protein level reveals that the CsFAOMT1 protein activities in the three tea germplasms with high EGCG3′′Me content all exhibit high activity with minimal differences between them. These results indicate that JX and PM can enrich EGCG3′′Me due to their high expression levels of CsFAOMT1. This study identified tea germplasm with high EGCG3′′Me content and elucidated the molecular mechanisms underlying its unique traits, providing important materials and theoretical basis for breeding new tea cultivars with high methylated catechin content.

As an important entomogenous fungus, Metarhizium has been extensively utilized in the biological control of agricultural and forestry pests. This study aimed to screen the most infective strain against E. grisescens from 7 preserved strains and verify its infectivity at different doses. Subsequently, the taxonomic status of the strain was determined through observation of morphological characteristics and methods for multigene phylogenetic tree analysis. Finally, the optimal culture medium, temperature and pH value for strain growth were investigated. The results indicate that the seven tested strains exhibited different control effects on the 3rd instar larvae of E. grisescens, with strain Ma54 exhibiting the highest virulence, achieving a corrected mortality rate of 81.67% after 10 d of treatment and an LT₅₀ (lethal time for 50% mortality) of 4.93 d. The mortality rate of E. grisescens shows a dose-response relationship with the spore concentration of strain Ma54. After 7 d of treatment under a high concentration of Metarhizium (1.0×10⁸ spores·mL^-1), the mortality rate reached 98.33%, and the LT₅₀ value was 4.09 days. Seven days after strain Ma54 infected E. grisescens, the cadavers were covered with mycelia and turned dark green. After 14 days of growth on PDA medium, the conidia further spread and appeared dark green. The phylogenetic trees of the ribosomal transcription factor, β-tubulin, and the largest subunit of RNA polymerase Ⅱ of strain Ma54 all clustered with Metarhizium anisopliae. The colony diameter, spore production per unit area, and spore germination rate of strain Ma54 were optimal under conditions of a PPDA medium, a temperature of 25 ℃, and a pH value of 7.0. This study obtained the Ma54 strain with high virulence against E. grisescens, authenticated it as M. anisopliae, and preliminarily clarified its growth conditions of the strain, laying a foundation for its subsequent utilization in the biological control of E. grisescens.