Journal of Tea Science

Advances on Sensory Characteristics and Physiological Activity of Qingzhuan Brick Tea

ZHANG Kaili, LI Xiang

Journal of Tea Science. 2025, 45(3): 361-378.

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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.

Research Progress on Health Effects of Tea Polyphenols

CHEN Dan, WANG Shanshan, ZHANG Jieru, ZHENG Qinqin, ZHANG Xiangchun, CHEN Hongping

Journal of Tea Science. 2025, 45(3): 379-392.

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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.

AI in Tea Breeding: A Case Study on Prediction of the Yellowing Trait

XU Xin, LI Yaqi, YANG Yiyang, XU Qi, QIAN Xuefei, MA Chunlei, MEI Jufen

Journal of Tea Science. 2025, 45(3): 393-401.

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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.

WGCNA Analysis of Differentially Expressed Genes between Parallel Variation and Normal Tea Stems and Leaves

ZHAI Xiuming, LI Jie, XIAO Fuliang, TANG Min, ZENG Lewu, HOU Yujia, TANG Yi

Journal of Tea Science. 2025, 45(3): 402-414.

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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.

Metabolomics Analysis of Different Resistant Tea Cultivars Infected by Acaphylla theae in The Early Stage

ZHANG Hui, LIU Fengjing, LI Huiling, LI Liangde, WANG Qingsen, WANG Dingfeng

Journal of Tea Science. 2025, 45(3): 415-426.

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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.

Screening, Identification and Culture Conditions of a Highly Virulent Metarhizium anisopliae Strain against Ectropis grisescens Warre

LI Liangde, LI Jinyu, LI Huiling, ZHANG Hui, WANG Dingfeng

Journal of Tea Science. 2025, 45(3): 427-438.

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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 (1.0×10⁸spores·mL^-1), the mortality rate reached 98.33%, and the LT₅₀value 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.

Cloning and Functional Analysis of Vitellogenin Genes (EonuVg) in Empoasca onukii and Their Response to Imidacloprid

PAN Cheng, XIA Luxia, WEI Kexin, WANG Mengxin, NIU Yuqun, HAN Baoyu

Journal of Tea Science. 2025, 45(3): 439-453.

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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.

Determination of Anthocyanin-like Substances in Tea by High Performance Liquid Chromatography

YE Shuixin, WANG Weiwei, ZHANG Mengxue, JIANG Heyuan, ZHANG Haihua

Journal of Tea Science. 2025, 45(3): 454-464.

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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.

Evaluation of Aroma Enhancement Effect of Jasmine Hydrosol on Jasmine Tea and Its Influencing Factors

GE Chenxi, TANG Desong, ZHANG Lin, FU Shangwen, ZHANG Yingbin, LIANG Huiling

Journal of Tea Science. 2025, 45(3): 465-484.

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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.

Unveiling the Characteristic Taste Quality Compounds of Jasmine Tea Based on Electronic Tongue and Metabolomics Techniques

CHEN Yuan, AN Huimin, HUANG Yiwen, JIANG Youcang, YING Jiaqi, WANG Sirui, LI Shi, LIU Zhonghua, HUANG Jian'an

Journal of Tea Science. 2025, 45(3): 485-496.

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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.

Improvement and Mechanism Analysis of Matcha on Mouse Model of Memory Acquisition Impairment

LIANG Zengcai, MA Caiyun, GUO Yu, ZHU Xiang, LU Taofeng, CHEN Liang, LI Qian

Journal of Tea Science. 2025, 45(3): 497-508.

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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.

The Effect of Pile-fermentation on the Chemical Composition and Antioxidant Activities of Liupao Tea Oligosaccharides

TANG Zhiqi, QIN Han'ao, XIA Ning, TENG Jianwen, HUANG Li, OU Xiaoxuan, CHEN Liping, WEI Wei, WANG Rui

Journal of Tea Science. 2025, 45(3): 509-521.

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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.

Research on Tea Bud Recognition Technology Based on Deep Transfer Learning

ZHU Shaohui, ZHAO Wenju, MA Bohui, YANG Hualin, DENG Fang

Journal of Tea Science. 2025, 45(3): 522-534.

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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.

The Effect of Operational Parameters of Plant Protection Unmanned Aerial Vehicle on the Droplet Deposition Distribution in Tea Canopy

WU Mengtao, LI Zhaoqun, YANG Yuzhou, MENG Xiangfei, LUO Zongxiu, BIAN Lei, XIU Chunli, FU Nanxia, CHEN Zongmao, WANG Guochang, CAI Xiaoming

Journal of Tea Science. 2025, 45(3): 535-544.

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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.

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