Research Paper

Content of Research Paper in our journal     Published in last 1 year |  In last 2 years |  In last 3 years |  All Please wait a minute... For Selected: Download Citations EndNote Reference Manager ProCite BibTeX RefWorks Toggle Thumbnails Select Selection and Validation of Internal Reference Genes for qRT-PCR Analysis under Fluoride Stress in Camellia sinensis Leaves LI Qinghui, LI Rui, WEN Xiaoju, NI Dejiang, WANG Mingle, CHEN Yuqiong Journal of Tea Science    2024, 44 (1): 27-36.   DOI: 10.13305/j.cnki.jts.2024.01.001 Abstract （74）      PDF（pc） （1966KB）（63）       Knowledge map    Save In order to screen the internal reference genes for quantitative real-time PCR analysis in tea leaves under fluoride stress, the low-fluoride cultivar ‘Fuding Dabaicha’ and the high-fluoride cultivar ‘Jinguanyin’ were used as experimental materials according to the fluoride evaluation results in these tea cultivars previously. The qRT-PCR technology combined with three Excel-based algorithms (geNorm, NormFinder and BestKeeper) were used to analyze the expression stabilities of eight candidate reference genes (CsACTIN, CsEF-1α, CseIF-4α, CsGAPDH, CsPP2A, CsTBP, CsTIP41 and CsUBC) in tea leaves (shoots and old leaves) under fluoride treatment (0.42 mmol·L-1 NaF) for different time periods (0, 1, 3, 7 d). The results indicate that under fluoride stress, the optimal combination of reference genes in tea shoots was CsEF-1α, CsTIP41, CsTBP and CsACTIN and the optimal combination of reference genes in old leaves was CsPP2A and CsUBC. Moreover, to further confirm the stability of the selected reference genes, the expression levels of CsFEX in tea shoots and old leaves were analyzed using their corresponding optimal internal reference gene combinations. The expression profiles of CsFEX in tea shoots or old leaves between the two cultivars were consistent, indicating that the combinations of four and two internal reference genes were sufficient for normalizing the target gene expression in tea shoots and old leaves under fluoride stress, respectively. Reference | Related Articles | Metrics Select Risk Assessment and Source Analysis of Heavy Metal Pollution in Chinese Tea Gardens in 2000-2022 Based on Meta-analysis YANG Yanhu, CHEN Xiaohan, ZHANG Xiaoqing, REN Dajun, ZHANG Shuqin, CHEN Wangsheng Journal of Tea Science    2024, 44 (1): 37-52.   DOI: 10.13305/j.cnki.jts.2024.01.002 Abstract （57）      PDF（pc） （1446KB）（50）       Knowledge map    Save Heavy metal pollution is one of the important factors affecting the ecological environment of tea gardens and the safety of tea products. This study collected literature on heavy metal (Cu, Pb, As, Hg, Cd, Cr, Zn, Ni) pollutions in tea garden soils in major tea producing areas in China, including Hubei, Hunan, Fujian, Yunnan, Guizhou and Sichuan. The weight of a single study was obtained using meta-analysis method to obtain the weighted average of heavy metal concentrations in tea garden soils in each province and across the country. The potential ecological risk index method and geological accumulation index method were used for ecological risk assessment, and source analysis using the APCS-MLR model was applied. The results show that compared with the background values, all 8 heavy metals were enriched to a certain extent, with Hg and Cd pollutions being more severe. The moderate and above risks of Hg were mainly distributed in inland provinces such as Guizhou, Shaanxi, Sichuan and Anhui. The moderate and above risks of Cd were mainly distributed in coastal provinces such as Guangdong, Fujian, Zhejiang, Jiangsu, Shandong, Hainan, etc. The two heavy metals show mild to moderate risks. Compared with other countries in the world, tea gardens or agricultural land in developing countries generally have higher levels of heavy metals, with Cd and Hg being the elements with more severe pollution levels. The source analysis results show that the first, second, third, and fourth principal components are natural sources, industrial activity pollution sources, traffic exhaust pollution sources, and agricultural activity pollution sources, respectively. Industrial and agricultural activities are the main pollution factors, with Hg mainly coming from industrial activities and Cd mainly coming from agricultural activities. Reference | Related Articles | Metrics Select Effects of Foliar Application of Different Concentrations of Organic-based Biostimulant Formulas on Yield and Quality of Tea (Camellia sinensis L.) in Red Soil Regions WANG Limin, CHEN Shiping, HUANG Dongfeng Journal of Tea Science    2024, 44 (1): 53-61.   DOI: 10.13305/j.cnki.jts.2024.01.007 Abstract （82）      PDF（pc） （903KB）（75）       Knowledge map    Save The purpose of this study was to evaluate the effect of different concentrations of organic-based biostimulant formulas (OBFs) on the yield and quality of tea (Camellia sinensis L.) in red soil regions. A field experiment was therefore conducted to investigate the nutrient uptake, yield, and quality of tea under different fertilization treatments. On the basis of conventional fertilization, foliar applications with the volume percentage concentration of OBFs including 0 (T0), 0.33% (T1), 0.66% (T2), 0.99% (T3), 1.32% (T4), and 1.65% (T5) were set up. The results show that foliar application of OBFs improved agronomic characteristics, enhanced nutrient uptake of tea plants and improved the tea yield and quality. Compared with the T0 treatment, tea yield in the T1, T2, T3, T4 and T5 treatments increased by 1.4, 1.4, 1.3, 2.1 and 2.4 times, respectively (P<0.05). In addition, as the concentrations of OBFs increased, the contents of total alkaloid, caffeine, and amino acids were first increased and then decreased. The contents of total alkaloid in the T1 and T2 treatments increased by 9.6% and 9.3%, caffeine increased by 9.3% and 11.4%, and amino acids increased by 5.0% and 12.4% in comparison with the T0 treatment, respectively (P<0.05). Meanwhile, under T1 and T2 treatments, nitrogen (N) uptake of tea leaves increased by 5.5% and 6.1%, phosphorus (P) increased by 19.9% and 13.3% and potassium (K) increased by 20.9% and 10.0%, respectively (P<0.05). Under T1 treatment, silicon (Si) increased by 14.8%. Furthermore, tea yield was positively correlated with bud density, 100-bud weight, leaf area and chlorophyll content. Meanwhile, the contents of total alkaloid and caffeine were positively related to N, P, K and Si contents in tea leaves, respectively. Similarly, there was a significant and positive relationship between N, P and K contents in tea leaves and the contents of amino acids and essential amino acids. Overall, foliar application with 1.65% OBFs could increase tea yield, while foliar application with 0.33% and 0.66% OBFs could promote N, P, K and Si uptake in tea leaves, improve agronomic characteristics, which is beneficial for tea yield and quality. Reference | Related Articles | Metrics Select A Grading Identification Method for Tea Buds Based on Improved YOLOv7-tiny HONG Konglin, WU Minghui, GAO Bo, FENG Yening Journal of Tea Science    2024, 44 (1): 62-74.   DOI: 10.13305/j.cnki.jts.2024.01.006 Abstract （66）      PDF（pc） （2946KB）（38）       Knowledge map    Save The intelligent grading and recognition of tea buds in a natural environment are fundamental for the automation of premium tea harvesting. To address the problems of low recognition accuracy and limited robustness caused by complex environmental factors like lighting, obstruction, and dense foliage, we propose an enhanced model based on YOLOv7-tiny. Firstly, a CBAM module was added into the small object detection layer of the YOLOv7-tiny model to enhance the model's ability to focus on small object features and reduce the interference of complex environments on tea bud recognition. We adjusted the spatial pyramid pooling structure to lower computational costs and improve detection speed. Additionally, we utilized a loss function combining IoU and NWD to further enhance the model's robustness in small object detection by addressing the sensitivity of the IoU mechanism to position deviations. Experimental results demonstrate that the proposed model achieves a detection accuracy of 91.15%, a recall rate of 88.54%, and a mean average precision of 92.66%. The model's size is 12.4 MB. Compared to the original model, this represents an improvement of 2.83%, 2.00%, and 1.47% in accuracy, recall rate, and mean average precision, respectively, with a significant increase of 0.1 MB in model size. Comparative experiments with different models show that our model exhibits fewer false negatives and false positives in multiple scenarios, along with higher confidence scores. The improved model can be applied to the bud grading and recognition process of premium tea harvesting robots. Reference | Related Articles | Metrics Select Experimental Study on High-quality Tea Plucking by Robot LI Yatao, ZHOU Yujie, WANG Shaoqing, CHEN Jianneng, HE Leiying, JIA Jiangming, WU Chuanyu Journal of Tea Science    2024, 44 (1): 75-83.   DOI: 10.13305/j.cnki.jts.2024.01.003 Abstract （73）      PDF（pc） （1757KB）（55）       Knowledge map    Save This study evaluated the performance of a newly developed track-type tea plucking robot on Longjing tea picking, including its detection accuracy, localization accuracy, end effector plucking accuracy, time consumption across each stage. The results show that the detection success rate of the developed robot was 88.54%, the localization success rate was 84.07%, the end effector plucking success rate was 87.22%, and the overall plucking success rate was 61.30%. The plucked tea leaves met the requirements of middle-grade Longjing tea. The single tea shoot plucking time was approximately 1.51 s, and the machine could pluck over 2 000 tea shoots per hour, basically achieving the picking efficiency of one machine replacing one worker. Reference | Related Articles | Metrics Select Study on the Glycosidically Bound Volatiles and Aroma Constituents in the Processing of Wuyi Rougui WU Zongjie, OU Xiaoxi, LIN Hongzheng, YU Xinru, CHEN Shouyue, WU Qingyang, LI Xinlei, SUN Yun Journal of Tea Science    2024, 44 (1): 84-100.   DOI: 10.13305/j.cnki.jts.2024.01.005 Abstract （71）      PDF（pc） （1428KB）（46）       Knowledge map    Save ‘Rougui’, the main cultivar of Wuyi rock tea, is characterized by a rich floral and pungent cinnamon aroma. To elucidate the contribution of key aroma constituents and glycosidically bound volatiles (GBVs) to Wuyi Rougui rock tea, this study employed ultra-high-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF/MS) and headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) to investigate the dynamic changes of GBVs and aroma constituents during the processing of Wuyi Rougui rock tea. The results reveal that a total of 276 aroma constituents were identified from 11 different processing stages of Wuyi Rougui rock tea. These aroma constituents belong to various chemical classes, including esters, alcohols, heterocyclic constituents, ketones, aldehydes and terpenes, with heterocyclic constituents, esters, terpenes and alcohols being the predominant aroma components. Orthogonal partial least squares-discriminant analysis (OPLS-DA) identified 35 characteristic aroma constituents in Wuyi Rougui rock tea, as indicated by their Variable Importance in Projection (VIP) values and Odor Activity Values (OAV) greater than 1. Notably, the contents of constituents associated with green and grassy flavor, such as (Z)-3-hexen-1-ol, (E)-2-nonenal and hexanal, exhibited decreasing trends during the processing, while aroma constituents associated with floral or fruity aromas, like linalool, benzyl alcohol, benzaldehyde, eugenol and β-ocimene, displayed increasing trends. Furthermore, in fresh leaves of Wuyi Rougui rock tea, aroma constituents including linalool, benzyl alcohol, benzaldehyde, 2-ethoxy-3-methylpyrazine and (E,E)-3,5-octadien-2-one exhibited ACI values greater than 1, suggesting they are key aroma constituents during the processing of Wuyi Rougui rock tea. Constituents such as dehydrocinnamyl alcohol and α-ionone contributed to the characteristic cinnamon aroma of Wuyi Rougui rock tea. In addition, ten GBVs were identified. During the processing, the contents of glucosides showed an upward trend, while primeveroside showed trend. The total contents of GBVs remained relatively stable. During the late stages of fermentation, both GBVs demonstrated declining trends, particularly constituents like benzyl primeveroside, 2-phenylethyl primeveroside, geranyl glucoside, linayl primeveroside and benzyl glucoside. The results indicate that GBVs were involved in the development of the faint scent and floral-fruity notes of Wuyi Rougui rock tea. This study clarified the role of characteristic aroma constituents and GBVs in the aroma formation of Wuyi Rougui rock tea, in order to better improve the aroma quality of Wuyi Rougui rock tea. Reference | Related Articles | Metrics Select Analysis of the Major Characteristic Aroma Compounds in Different Grades of Jingshan Tea ZHANG Huiyuan, MA Kuan, GAO Jing, JIN Yugu, WANG Yujie, SU Zhucheng, NING Jingming, CHEN Hongping, HOU Zhiwei Journal of Tea Science    2024, 44 (1): 101-118.   DOI: 10.13305/j.cnki.jts.2024.01.009 Abstract （104）      PDF（pc） （1818KB）（78）       Knowledge map    Save To characterize the difference of odorants among different grades of Jingshan tea, we investigated the super grade, the first grade, the second grade and the third grade of Jingshan tea by stir bar sorptive extraction gas chromatography-mass spectrometry (SBSE-GC-MS), headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) and gas chromatography-olfactometry (GC-O) analysis. Herein, we detected and identified 161 volatile organic compounds. The differences between the four grades of Jingshan tea were revealed by principal component analysis (PCA) and hierarchical cluster analysis (HCA). The variable importance in projection (VIP) of the orthogonal partial least squares discriminant analysis (OPLS-DA) was used to determine candidate differential volatile compounds among tea samples of different grades and further screening of differential compounds was carried out through analysis of relative odor activity value (ROAV) and GC-O analysis. A total of 18 volatile compounds were identified as key odorants for the discrimination of different grades of Jingshan tea, including linalool, geraniol, indole, (Z)-jasmone, dimethyl sulfide, etc. Among them, the contents of hoterienol, methyl jasmonate, and indole in the super grade Jingshan tea were significantly higher than those in other grades, and together with (Z)-jasmone, δ-decalactone, and 1-octen-3-ol and other aroma-active compounds constitute the characteristic floral aroma of super grade Jingshan tea samples. This study revealed significant differences in the characteristic volatile compounds among different grades of Jingshan tea, providing a reference for distinguishing the grades of green teas by chemometrics combined with multivariate statistical analysis. Reference | Related Articles | Metrics Select Inductive Effect and Mechanism of EGCG on Beiging of White Adipose Tissue in High-fat Diet-fed GK Rats WAN Liwei, ZENG Hongzhe, PENG Liyuan, WEN Shuai, LIU Changwei, BAO Sudu, AN Qin, HUANG Jian'an, LIU Zhonghua Journal of Tea Science    2024, 44 (1): 119-132.   DOI: 10.13305/j.cnki.jts.2024.01.008 Abstract （63）      PDF（pc） （1738KB）（33）       Knowledge map    Save The types of adipose tissue are closely related to human metabolism. Transforming white adipocytes into thermogenic beige adipocytes through dietary or nutritional interventions is a safe strategy to reduce fat accumulation and regulate metabolism. Currently, research on the role of white adipose tissue beiging has mainly focused on obese populations. To explore the effect of EGCG on promoting the beiging of white adipose tissue in non-obese individuals with metabolic disorders and its related mechanisms, this study used non-obese, spontaneously diabetic type 2 GK rats. These rats were fed a high-fat diet and received 40 mg·kg-1 and 80 mg·kg-1 EGCG daily by gavage. In this study, we assessed body weight, food intake, cellular morphology of adipose tissue, gene expression levels associated with beiging, and protein expression levels of UCP1 in GK rats. Additionally, transcriptome sequencing was also performed on epididymal white adipose tissue. The results show that gavage intervention with 80 mg·kg-1 EGCG has no significant effect on the food intake and body weight of GK rats. It induced a trend of beiging in adipocytes towards a multilocular phenotype transformation, characterized by a decrease in cell size and an increase in cell number. Moreover, it significantly upregulated the expression levels of beiging-related genes Pparg, Ppargc1a, Ucp1 and the protein expression level of UCP1.This demonstrates the inducing effect of EGCG on the beiging of visceral epididymal white adipose tissue in high-fat diet-fed GK rats, indicating its potential in the regulation of lipid metabolism. Combined with transcriptome analysis, the results suggest that the induction mechanism of EGCG on the beiging of white adipose tissue in high-fat diet-fed GK rats may be associated with the PPAR signaling pathway, PI3K/Akt, and MAPK signaling pathway. Reference | Related Articles | Metrics Select Establishment of Lu'an Guapian Green Tea Brewing Control Chart ZHAO Xiaoyi, CHEN Aini, JIANG Qing, ZHAO Lei, QIU Tong, FANG Wanxin, LIANG Chuyun, SHARIPOVA Alina, DAI Qianying Journal of Tea Science    2024, 44 (1): 133-148.   DOI: 10.13305/j.cnki.jts.2024.01.012 Abstract （67）      PDF（pc） （2403KB）（55）       Knowledge map    Save The Coffee Brewing Control Chart is widely used in the coffee industry. According to the evaluation indices of coffee, this study applied extraction yield (EY) and total dissolved solids (TDS), which represent flavor balance and strength respectively, as quality indices to evaluate Lu'an Guapian green tea (LAGP) infusion. The optimum range of EY and TDS which yielded the maximum consumer acceptance were estimated by survival analysis. EY ranged from 2.53% to 4.57%, and TDS ranged from 0.14% to 0.28%. The LAGP Brewing Control Chart was established regarding the optimum range as the “ideal” zone. The chart was verified by both consumers and experts. This study indicates that when tea to water ratios (g∶mL) ranged from 1∶30 to 1∶15, brewing temperature ranged from 85 ℃ to 100 ℃, regulating brewing time of the first, second and third infusion less than 33 s, 15 s and 13 s, respectively, the ideal infusion can be gained. The study scientifically provided theory basis for guiding green tea brewing like LAGP. Reference | Related Articles | Metrics Select Study on the Spatiotemporal Evolution and Spatial Differentiation Pattern of Carbon Sink in China’s Tea Industry YUAN Liwen, ZHANG Junbiao, QIN Jiangnan Journal of Tea Science    2024, 44 (1): 149-160.   DOI: 10.13305/j.cnki.jts.2024.01.011 Abstract （58）      PDF（pc） （655KB）（47）       Knowledge map    Save The tea garden ecosystem has an important carbon storage function. Analyzing and evaluating the carbon sink level during the production and planting process of tea gardens is of great significance for scientifically evaluating the potential ecological value of tea gardens and promoting the green and low-carbon development of the tea industry. This paper selected data from 16 major tea producing provinces in China from 1978 to 2020, used biomass models of tea plant growth cycles and soil carbon content models to calculate and evaluate the basic situation of carbon sinks in China’s tea industry. The center of gravity fitting model was used to analyze the spatiotemporal evolution of carbon sinks in the tea industry, and the driving factors of spatial differentiation were explored in conjunction with geographic detector models. The results show that: (1) The total carbon sink of China’s tea industry had shown a phased growth trend, reaching 735.311 million tons in 2020, and the accumulation of soil carbon sink was higher than that of plant carbon sink. The carbon sink intensity showed a “rise-decrease-rise” characteristic. (2) There were significant differences in carbon sink intensity among different provinces in the tea industry. High-intensity provinces were concentrated in the eastern coastal and western regions of China, and the carbon sink gravity center had long been located within Hunan province, but there was a slight trend of westward displacement. (3) The agricultural subsidies and the development level of agricultural economy were important driving forces that affect the spatial distribution pattern of carbon sinks in China’s tea industry, but there were differences in the dominant factors for the spatial differentiation of carbon sinks in different regions. Based on this, this paper proposed relevant suggestions from the management and operation of carbon sinks in the tea industry, as well as the formulation of industrial policies. Reference | Related Articles | Metrics Select Research on the Path to Realize the Value of Tea Agricultural Cultural Heritage: Empirical Analysis Based on 31 Typical Cases MA Jie, YE Chaoyang, MAO Liyu Journal of Tea Science    2024, 44 (1): 161-174.   DOI: 10.13305/j.cnki.jts.2024.01.013 Abstract （61）      PDF（pc） （584KB）（42）       Knowledge map    Save The realization of the value of tea agricultural cultural heritage (TACH) is an important way for its protection and sustainable development. Based on the technology-organization-environment framework (TOE), this study explored the configuration effects of TOE condition variables on TACH value realization, as well as the linkage matching relationship among different elements. Based on 31 typical cases of TACH as research samples, the Fuzzy-sets qualitative comparative analysis (FsQCA) method was applied to explore the influencing factors and driving paths of TACH value realization. This study found that: (1) the realization of the value of TACH is the result of the combined action of necessary and sufficient conditions. (2) the realization of the value of high-level TACH is the result of the combination of core conditions and marginal conditions, with three typical models: "Collaborative Organizational Environment Type", "Social Resource Driven Type " and "Comprehensive Coupling Type". (3) The driving combination for the realization of non-high-level and high-level TACH value is asymmetric. Therefore, different paths could be chosen based on one's own resource endowment and external factors, in order to promote TACH value realization. Reference | Related Articles | Metrics Select QTL Mapping and Candidate Gene Analysis for Timing of Spring Bud Flush in Tea Plants (Camellia sinensis) WANG Liubin, WU Liyun, WEI Kang, WANG Liyuan Journal of Tea Science    2023, 43 (6): 747-756.   DOI: 10.13305/j.cnki.jts.2023.06.012 Abstract （137）      PDF（pc） （1696KB）（115）       Knowledge map    Save The timing of spring bud flush (TBF) is an important agronomic trait of tea plants, which has great effects on the flavor quality and economic benefits of tea. In this study, to discover key candidate genes regulating TBF, a F1 population of ‘Longjing 43’× ‘Baihaozao’ comprising 327 offspring was used and a two years’ investigation of TBF were performed in the tea garden. Based on the high-density genetic map constructed from the F1 population, QTL mapping for the sprouting index (SPI) of tea plants was performed using MapQTL 6.0 and GACD 1.2 software. The phenotypes of SPI in 2022 and 2023 show significant trait segregation and exhibit obvious quantitative trait characteristics in the progeny population. MapQTL 6.0 was identified as a primary QTL (qSPI-5-1), which explained 18.30% (2022) and 7.60% (2023) of phenotypic variations, respectively. GACD1.2 software identified two stable QTLs (qSPI-1, qSPI-5-2), which explained 2.75%-18.40% of phenotypic variations. While qSPI-5-2 and qSPI-5-1 were largely overlapped. The confidence intervals of the above QTLs were compared to the reference genome of tea plants, and 23 candidate genes related to the TBF were found by function annotation analysis. These results provided theoretical references for further investigation on the regulatory genes and molecular mechanisms of spring bud flushing in tea plants. Reference | Related Articles | Metrics Select Analysis of Photosynthetic and Fluorescence Characteristics of Albino Tea Plants LIU Dongna, GONG Xuejiao, LI Lanying, HUANG Fan, YAO Yu, XU Yaqiong, GAO Yuan, LUO Fan Journal of Tea Science    2023, 43 (6): 757-768.   DOI: 10.13305/j.cnki.jts.2023.06.002 Abstract （114）      PDF（pc） （557KB）（136）       Knowledge map    Save To facilitate the scientific assessment of germplasm evaluation and cultivation management of albino tea plants (Camellia sinensis L.), this study investigated the photosynthetic pigment contents, as well as the photosynthetic and chlorophyll fluorescence characteristics of three albino cultivars, with the normal tea cultivar ‘Fuding dabaicha’ (FD) as the control. The results show that (1) the total chlorophyll content of yellow tea leaves was 71.7%-86.8% lower than that of the control cultivar, and the total carotenoid content remained between 0.16 mg·g-1 and 0.31 mg·g-1. (2) The net photosynthetic rate (Pn), stomatal conductance (Gs), water use efficiency (WUE), the maximum net photosynthetic rate (Pn max), and light saturation point (LSP) of three albino tea cultivars were significantly decreased, and the optical compensation point (LCP) was significantly was than those of the control. (3) The photosynthetic processes of albino tea cultivars, such as absorption, transformation and consumption of light energy were significantly different from those of the control. Among them, the relative variable fluorescence at L and J points in the OJIP curve of albino tea cultivars ‘Jinfeng 2’ (JF2) and ‘Zhonghuang 1’ (ZH1) were significantly higher. Among the chlorophyll fluorescence kinetic parameters, MO, DIO/RC, φDO and φRO increased significantly, while FV/FO, ETO/RC, φPO, φEO, ΨEO and PIabs decreased significantly. Our study found that the photosynthetic efficiency, potential and ecological adaptability of albino tea leaves were significantly decreased. The significant reduction of photosynthetic pigment, the significant decrease of PSⅡ light capture and photosynthetic electron transfer efficiency, and the significant increase of heat dissipation energy were the considerable reasons for inhibition of photosynthetic performance in albino tea plants. Reference | Related Articles | Metrics Select Population Structure and Genetic Differences of Tea Germplasm Resources in Fujian YANG Jun, ZHANG Lilan, ZHANG Wenjing, CHEN Linhai, ZHENG Guohua, LI Yijing, WANG Rangjian Journal of Tea Science    2023, 43 (6): 769-783.   DOI: 10.13305/j.cnki.jts.2023.06.006 Abstract （125）      PDF（pc） （749KB）（156）       Knowledge map    Save The population genetic structure, genetic diversity, genetic differentiation, gene flow, molecular variance of 208 tea germplasm resources in Fujian were studied by using 38 pairs of SSR fluorescent primers, and the leaf traits were also investigated. The results show that the Nei’s genetic diversity index and Shannon’s information index of 208 tea resources in Fujian were 0.674 and 1.444, respectively. The average values of leaf area and length-width ratio were 27.442 cm2 and 2.516, respectively. The genetic variation of tea germplasm in Fujian were mainly originated from individual genetic variation. The test materials were divided into 8 groups by the structure software analysis. The material sources in groups a, b, f, and h were single, while the material sources in groups c, d, e, and g were complex. The genetic background of tea population in different regions was similar. There were a total of 40 tea cultivars from Fujian in groups a, b, and e. Group a was mainly cultivars suitable for processing green tea. Group b was mainly cultivars suitable for processing oolong tea. The representative cultivars within group e were suitable for processing green tea. There is a certain correlation between the group attributes of group a, group b, group e and the suitable tea cultivars. Group c included the resources from Nanjing county, Yunxiao county and Pinghe county, with relatively close geographical locations. The group attributes are related to geographical sources. The gene flow value between group g and group e was 6.321, indicating frequent gene exchange between groups. The clustering of group similarity coefficients shows that group d and group b were closely related. The genetic differentiation between group h and other groups was obvious, and the characters of leaf area and leaf serration number were significantly different (P<0.05). The genetic relationship between group f and other groups was relatively distant, and there were significant differences in the characteristics of leaf serration number and leaf vein logarithm (P<0.05), showing that both group h and group f had certain uniqueness and need further identification. These research results provided a certain reference for the identification, screening, and utilization of tea germplasm resources in Fujian. Reference | Related Articles | Metrics Select The Investigation of the Ameliorate Effect and Mechanism of EGCG on Non-obese GK Rat with Diabetic Kidney Damage PENG Liyuan, ZENG Hongzhe, WAN Liwei, WEN Shuai, LIU Changwei, AN Qin, BAO Sudu, HUANG Jian'an, LIU Zhonghua Journal of Tea Science    2023, 43 (6): 784-794.   DOI: 10.13305/j.cnki.jts.2023.06.003 Abstract （131）      PDF（pc） （2099KB）（78）       Knowledge map    Save Epigallocatechin gallate (EGCG) is an antioxidant and anti-inflammatory natural active ingredient, and fewer studies have been conducted on the antioxidant and anti-inflammatory effects of EGCG in DKD and the regulatory mechanisms. This study investigated the effect and mechanism of EGCG on diabetic kidney damage in non-obese GK rats with idiopathic T2DM. Two different doses of EGCG (10 mg·kg-1 and 120 mg·kg-1) were administered to GK rats for 4 weeks. The body weight and daily food intake of rats were monitored during the experiment. At the end of the experiment, the serum and kidney tissues were collected to detect some kidney biochemical and pathological indicators and Nrf2-Keap1/MAPK signaling pathway related gene expression levels. The results show that EGCG could improve the kidney morphology and significantly increase the activities of antioxidant enzymes (such as SOD, CAT and GSH-Px), and inhibit the release of proinflammatory cytokines (MCP-1, IL-1β). In addition, EGCG could restrain oxidant stress by up-regulate the expression level of Nrf2 and inhibit inflammation by down-regulating the expression levels of JNK, NF-κB and P38 genes in kidney. The improvement effect of high dose was better than that of low dose in the experimental range. In conclusion, these results indicate that EGCG could ameliorate kidney injury caused by diabetes, and its mechanism might be related to anti-oxidative stress mediated by Nrf2-Keap1/MAPK signaling pathways. Reference | Related Articles | Metrics Select Analysis of Genetic Diversity and Genetic Structure in Geographic Populations of Stephanitis chinensis from China Based on Mitochondrial DNA COI Sequence CHEN Shichun, JIANG Hongyan, LIAO Shuran, CHEN Tingxu, WANG Xiaoqing Journal of Tea Science    2023, 43 (6): 795-805.   DOI: 10.13305/j.cnki.jts.2023.06.008 Abstract （92）      PDF（pc） （1213KB）（75）       Knowledge map    Save The tea lace bug, Stephanitis chinensis, is an important pest of the southwest tea region in China, which has spread and caused disasters in recent years. To analyze the ecological adaptation mechanism and disaster law of S. chinensis, COI sequences of 240 adults from 12 populations of this pest were sequenced. The genetic differentiation, gene flow level and molecular variance were analyzed by DnaSP 6.12.03, Arlequin 3.5.2.2 and MEGA 7.0.26, respectively. There were 75 mutation sites and 38 haplotypes in the COI sequences of 12 geographic populations, and only Hap13 was a shared haplotype. Haplotype diversity index (Hd) of the total population was 0.827 79, Hd values between geographical populations ranged from 0.00 to 0.85. Fixed coefficient (FST) and gene flow (Nm) value of total population were 0.864 26 and 0.039 87, respectively. The results indicate that there are a high degree of genetic differentiation and a small degree of gene exchange of the total population in China. Population pairs of 5 populations (CQCK, CQWX, HBES, HBSY and SXHZ) had low genetic differentiation and frequent gene exchange (FST<0.06, Nm>4.50), while other population pairs had high genetic differentiation and less gene exchange (FST>0.25, Nm<1.00). Molecular variance analysis (AMOVA) supports that the genetic differentiation was mainly among populations (86.43%). Tajima's D and Fu's Fs neutrality test support that population expansion events occurred in the CQBN, HBES populations and the whole population around the Daba Mountains. In this study, the risk of both invasion expansion and original population expansion of S. chinensis in China was analyzed and speculated. It suggests that the field monitoring of the tea lace bug should be strengthened in tea plantations. Reference | Related Articles | Metrics Select Study on the Influence of Tea Green Leafhopper Infestation on the Tenderness of Fresh Tea Leaves and the Extraction Rate of Metabolites Related to Oolong Tea Quality WU Shuhua, MAO Kaiquan, CHEN Jiaming, LI Jianlong, XUE Jinghua, ZENG Lanting, YANG Yuhua, GU Dachuan Journal of Tea Science    2023, 43 (6): 806-822.   DOI: 10.13305/j.cnki.jts.2023.06.005 Abstract （125）      PDF（pc） （4187KB）（105）       Knowledge map    Save Tea green leafhopper is a major insect widely distributed in tea gardens, which has a significant impact on the yield and quality of tea. However, the effects of tea green leafhopper infestation on the tenderness of fresh tea leaves and the extraction rate of metabolites related to oolong tea quality remain unclear. By means of shear force measurement, broken tea rate analysis, oolong tea brewing, metabolite analysis and correlation analysis, it was found that the infestation of tea green leafhoppers significantly increased the contents of cell wall materials lignin, cellulose and pectin, and decreased the tenderness of fresh tea leaves and broken tea rate. The extraction rates of tea polyphenols, free amino acids, soluble sugars, catechin monomers, amino acid monomers and theanine were affected. Moreover, except for epicatechin gallate (ECG), the extraction of these taste substances and the tenderness of fresh tea leaves were significantly correlated with the contents of cell wall materials. In this study, the extraction rule of taste quality metabolites after tea green leafhoppers infestation was explored, and the influence of tea green leafhopper infestation on quality traits was explored from three aspects: tea picking, processing and brewing. Reference | Related Articles | Metrics Select Changes of Rhizospheric Pathogen Alternaria sp. and Its Antagonistic Bacteria Pseudomonas sp. of Continuous Cropping Tea Plants Mediated by Phenolic Acids LI Yanchun, WANG Yixiang, YE Jing, LI Zhaowei Journal of Tea Science    2023, 43 (6): 823-834.   DOI: 10.13305/j.cnki.jts.2023.06.007 Abstract （99）      PDF（pc） （1798KB）（83）       Knowledge map    Save Tea plant is an important economic crop in China. Long-term continuous cropping of tea plants has resulted in severe problems such as the imbalance of soil microbial community structure, soil disease exacerbation. Exploring the molecular mechanism underlying the formation of continuous cropping obstacles in Tieguanyin tea gardens is of great significance for seeking effective techniques for preventing and controlling the continuous cropping obstacle phenomenon. In this study, the pathogen and its antagonistic bacteria were isolated from the rhizosphere of Tieguanyin tea garden and identified by methods such as microbial isolation and purification, and plate confrontation. Quantitative analysis was conducted on the number of pathogen and its antagonistic bacteria in the rhizospheric soils of different continuous cropping years (0, 1, 10, and 20 years). Simultaneously, high-performance liquid chromatography (HPLC) technology was used to detect the changes of phenolic acid contents in the rhizospheric soils of different continuous cropping years, and the ratio of various phenolic acids in the soils was simulated to investigate the effects of phenolic acids on the rhizospheric pathogen and its antagonistic bacteria. The results show that one pathogenic fungus Alternaria sp. was isolated and identified from the infected roots of Tieguanyin under 20 years’ continuous cropping, and an antagonistic bacteria Pseudomonas sp. was identified from the rhizospheric soils. Fluorescence quantitative PCR analysis shows that the content of Alternaria sp. in 20 years’ continuous cropping soils was significantly higher than 1 year tea garden, while the content of Pseudomonas sp. was significantly lower. Five phenolic acids, including p-hydroxybenzoic acid, vanillic acid, syringic acid, vanillin, and ferulic acid, were detected in the rhizospheric soils, with an average ratio of 38∶229∶11∶11∶3. Phenolic acids did not accumulate in the soils, but showed a trend of first increasing and then decreasing with the increase of continuous cropping years. Simulation experiments found that mixed phenolic acids at low to medium concentrations (30-120 mmol·L-1) could significantly promote the mycelial growth of Alternaria sp. while single phenolic acid such as p-hydroxybenzoic acid, vanillic acid, and syringic acid at low concentrations (30 mmol·L-1 and 60 mmol·L-1) also significantly accelerated the mycelial growth of Alternaria sp.. However, p-hydroxybenzoic acid had an inhibitory effect on the growth of Pseudomonas sp., and the inhibitory effect increased with the increase of p-hydroxybenzoic acid concentration. Mixed phenolic acid and other single phenolic acids had no significant effect on the growth of Pseudomonas sp.. Therefore, phenolic acids, the root exudates of Tieguanyin tea plants, have different ecological effects on the key microbial communities in the rhizospheric soils, and are important factors causing the imbalance of microbial community structure and the increase of severe diseases and other continuous cropping obstacles. The research results provided a theoretical basis for further revealing the mechanism of continuous cropping obstacles in Tieguanyin tea plants. Reference | Related Articles | Metrics Select Quantitative Analysis of Tea Leaf Serration Morphological Characteristics Based on Image Analysis TANG Min, ZHONG Qitian, XU Jin, XIAO Fuliang, LI Jie, ZHAI Xiuming, HOU Yujia, GU Yu Journal of Tea Science    2023, 43 (6): 835-843.   DOI: 10.13305/j.cnki.jts.2023.06.004 Abstract （98）      PDF（pc） （970KB）（74）       Knowledge map    Save The size, shape, and arrangement of tea leaf serrations are important criteria for assessing and evaluating tea germplasm resources. However, for a long time, the determination of these criteria has mainly relied on the experience of technicians, resulting in subjective judgments and uncertainties. In this study, a custom convolutional operator based on the geometric morphological features of leaves was introduced, and the existing image recognition algorithms were optimized. A quantification method for tea leaf serrations based on leaf image analysis was proposed. Through experimental validation, the results show that this method can rapidly and accurately obtain basic parameters such as leaf area, perimeter, and number of serrations. It can also quantify descriptive indicators such as serration sharpness, serration depth, and serration density using custom operators. The coefficients of variation for the quantified results are all less than 1%, indicating strong repeatability and high stability. Compared to manual subjective identification, the measurement time of this method does not exceed 30 s, effectively enhancing the accuracy and efficiency of evaluating the morphological characteristics of tea leaf serrations. It provided a new approach and perspective for the quantitative evaluation of tea germplasm resources. Reference | Related Articles | Metrics Select Research on the Prototype and Process Parameters of Oolong Tea Rocking Green Mechanism of Non-circular Gear Planetary Gear Train LIU Limin Journal of Tea Science    2023, 43 (6): 844-856.   DOI: 10.13305/j.cnki.jts.20231025.001 Abstract （78）      PDF（pc） （1071KB）（63）       Knowledge map    Save In response to the problems of uneven tea stirring quality and poor effect caused by insufficient friction between fresh leaves in the current oolong tea rocking green mechanism, this paper designed a set of oolong tea stirring mechanism based on a non-circular gear planetary gear train. The kinematics analysis model of the mechanism was established and its optimal mechanism parameters were obtained. The pitch curve and tooth profile parameters (m=2, α=20°, z=51) of the non-circular gear were designed and obtained using MATLAB software. The structure design and prototype development of the device were completed. On this basis, a 3-factor and 4-level orthogonal experiment was designed and carried out to evaluate the stirring effect of oolong tea. Multiple indicators were transformed into a single indicator to obtain a comprehensive score that can evaluate the shaking effect. The optimal process parameters were determined through orthogonal test analysis. Under the combination of these process parameters, the effective shaking rate of oolong tea fresh leaves was 87.52%, the water loss rate was 30.19%, and the comprehensive score was 97.02% of traditional manual shaking. The experimental results show that the oolong tea rocking green mechanism and the non-circular gear planetary gear train could meet the shaking needs of different degrees of tenderness and quantities of oolong tea, making the processed oolong tea more similar to manual stirring. Reference | Related Articles | Metrics Select Determination of Glyphosate and Its Metabolites in Tea by Automatic Solid Phase Extraction Combined with UPLC-MS/MS YI Huajuan, ZHU Jieling, ZHOU Ruizheng, ZHENG Yaolin, ZHANG Shuquan, YANG Le, SU Yonglun Journal of Tea Science    2023, 43 (6): 857-869.   DOI: 10.13305/j.cnki.jts.2023.06.010 Abstract （98）      PDF（pc） （507KB）（69）       Knowledge map    Save An analytical method for the determination of glyphosate and its metabolite aminomethylphosphonic acid in tea was established by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The samples were extracted and preliminarily purified using a water dichloromethane system and the sample matrix was further purified by mixed-mode cation exchanger column filled with polystyrene bonded benzenesulfonic acid in an automatic solid phase extractor. The optimal derivation conditions obtained by orthogonal test and variance analysis were 5% sodium borate buffer solution and 10 mg·mL-1 FMOC-Cl derivatizing agent for derivatization at room temperature for 2 h. The derived sample solution was subjected to gradient elution separation on HSS T3 column and 5 mmol·L-1 ammonium acetate solution (containing 0.1% formic acid)-acetonitrile mobile phase system. The targets were analyzed by UPLC-MS/MS and quantified by internal standard method. The linearity of glyphosate and aminomethylphosphonic acid was good in the concentration range of 0.2-50 ng·mL-1 and the correlation coefficient (R2) was greater than 0.999. The detection limit of the method was 2 μg·kg-1, and the quantitation limit was 5 μg·kg-1. The recoveries of 5, 50 and 250 μg·kg-1 were in range of 94.2%-106.7% with relative standard deviations of 3.8%-4.9%, at low, medium and high spiked levels. The method is suitable for the determination of glyphosate and aminomethylphosphonic acid residues in daily large quantities of tea samples in the laboratory with the advantages of high efficiency, high accuracy, high throughput, low matrix interference and high degree of automation. Reference | Related Articles | Metrics Select Does Digital Capital Influence Consumers to Increase Online Tea Purchases? An Empirical Analysis Based on 4 090 Consumer Samples GAO Feng, XU Jianghong, CHEN Fuqiao Journal of Tea Science    2023, 43 (6): 870-880.   DOI: 10.13305/j.cnki.jts.2023.06.001 Abstract （118）      PDF（pc） （593KB）（96）       Knowledge map    Save With the rapid development and widespread application of digital technology, consumer digital capital continues to accumulate, profoundly influencing their choice of shopping channels. Based on survey data from 4 090 tea consumers within the National Tea Industry Technical System, this study measured the consumer digital capital index and employed the ordinary least squares (OLS), instrumental variable (IV), and propensity score matching (PSM) methods to examine the impact of digital capital on consumers' online tea purchases. The research further explored the heterogeneity of this influence across consumers with different characteristics and delved into the moderating effect of digital technology security within this context. It was found that: (1) An increase in consumer digital capital led to higher expenditures on online tea purchases. (2) The impact of digital capital was more pronounced in young people, higher-income groups, and consumers who buy tea for personal consumption. (3) The decision security of digital technology played a positive moderating role in the relationship between digital capital and online tea purchases, particularly transaction security. However, the moderating effect of information security was not significant. In summary, the increase in consumer digital capital is the trend. Tea enterprises should seize the opportunities presented by digital transformation and actively establish online sales channels. The government should provide comprehensive support in terms of policies, funding, and technology for the digital transformation of tea enterprises. Simultaneously, there should be increased supervision of online sales markets to maintain quality and safety, creating a salubrious and well-ordered online tea trading market environment. Reference | Related Articles | Metrics Select The Impact of Organic Certification on the Business Profit of Tea Enterprises: Counterfactual Estimation Based on Propensity Score Matching YANG Xulin, PAN Changjian, JIANG Renhua Journal of Tea Science    2023, 43 (6): 881-890.   DOI: 10.13305/j.cnki.jts.2023.06.009 Abstract （115）      PDF（pc） （354KB）（68）       Knowledge map    Save This paper empirically examined the impact of organic certification on tea enterprises’ business profit using the propensity score matching method based on the data of 288 tea enterprises nationwide. The empirical evidence shows that organic certification has a positive effect on the business profit of tea enterprises, and this effect is heterogeneous in different regions and different tea plantation sizes. Compared with the central and western tea enterprises, the participation of eastern enterprises in organic certification has a significant effect on improving business profits. Compared with tea enterprises with a median or higher area of their own tea gardens, enterprises with smaller area of their own tea gardens have a greater benefit from participating in organic certification. Accordingly, governments can support tea enterprises to carry out organic certification in the framework of green development. Enterprises in the central and western regions can learn from the practical experience of the development of organic tea in eastern enterprises. Tea enterprises need to combine their own development positioning and market demand, consider whether to promote the quality and efficiency of enterprises through organic certification. Reference | Related Articles | Metrics Select Catalytic Function, Promoter Structure and Functional Analysis of CsNUDX1-cyto in Different Tea Cultivars YANG Jihong, ZHOU Hanchen, XU Yujie Journal of Tea Science    2023, 43 (5): 621-630.   DOI: 10.13305/j.cnki.jts.2023.05.001 Abstract （188）      PDF（pc） （1842KB）（139）       Knowledge map    Save Geraniol is an important monoterpenoid in tea plants, and its accumulation varies greatly among different tea cultivars. The recent study shows that CsNUDX1-cyto is responsible for the production of geraniol and its glycosides in tea plants. In order to explore the differences in the catalytic function and regulation of CsNUDX1-cyto in different tea cultivars, this study analyzed the differences in the accumulation of geraniol and expression patterns of CsNUDX1-cyto, and analyzed the differences in the catalytic function, promoter structure and function of CsNUDX1-cyto in seven tea cultivars. The result shows that CsNUDX1-cyto expression was positively correlated with geraniol content (r=0.805). The content of geranyl in fresh leaves of Camellia sinensis var. sinensis (CSS) was significantly higher than that in C. sinensis var. assamica (CSA) cultivars. Agrobacterium tumefaciens-mediated genetic transformation system shows that CsNUDX1-cyto of different tea cultivars could promote the biosynthesis of geraniol. Analysis of promoter activity shows that CsNUDX1-cyto promoter had the weakest activity in ‘Yunkang 10’, and the structural analysis shows that the promoter of CsNUDX1-cyto in ‘Yunkang 10’ had an 185 base sequence insertion at the transcription start site -33, making the enhancing element CAAT-box located at -133 (CAAT-boxes in other cultivars were located at -47). The results of this study indicate that CsNUDX1-cyto in different tea cultivars could promote geraniol biosynthesis, but the genetic diversity of the promoter region results in differences in its expression level. Reference | Related Articles | Metrics Select Construction of Flavor Wheel and Quantitative Sensory Description Analysis of Pu'er Tea and Fu Brick Tea CHEN Guohe, HU Tengfei, XIE He, FU Wenjie, ZHAI Yuke, BAO Sudou, AN Qin, WANG Chao, WANG Yingzi, LIU Zhonghua, HUANG Jian'an Journal of Tea Science    2023, 43 (5): 631-644.   DOI: 10.13305/j.cnki.jts.2023.05.008 Abstract （240）      PDF（pc） （1988KB）（232）       Knowledge map    Save Flavor wheel is a simple and easy method to understand descriptor system, which is convenient for consumers to communicate the sensory flavor attributes of Pu'er tea and Fu brick tea. In this study, by establishing a sensory evaluation team, sensory evaluation was conducted on the flavor of Pu'er tea and Fu brick tea, and the flavor wheels of Pu'er tea and Fu brick tea were drawn from two dimensions: aroma and taste. On this basis, a vocabulary for quantitative sensory description of Pu'er tea and Fu brick tea was established by setting reference samples with different intensities for 23 typical sensory descriptions. Furthermore, using the M-value method combined with analysis of variance and multivariate statistical analysis, the main sensory descriptors that can better describe Pu'er tea and Fu brick tea were selected. A total of 7 aroma descriptors (woody, sweet aroma, herbal, ferment, glutinous, jujube and aged) and 5 flavor descriptors (sweet taste, bitter, astringent, sour and mellow and thick) were selected for Pu'er tea, and 5 aroma descriptors (woody, sweet aroma, herbal, aged and fungal floral) and 5 flavor descriptors (sweet taste, bitter, astringent, sour and mellow and thick) were identified for Fu brick tea, and these descriptors can better evaluate the sensory quality characteristics of Pu'er tea and Fu brick tea samples. The results of this study provide application value for distinguishing and evaluating the sensory flavor characteristics of Pu'er tea and Fu brick tea, as well as in the development of their products. Reference | Related Articles | Metrics Select Exploring the Potential Mechanism of Hypoglycemic Effect of Fungus Fermented Black Tea Based on Liver Transcriptomics ZENG Hongzhe, PENG Liyuan, WAN Liwei, LIU Changwei, FANG Wenwen, WANG Kuofei, ZHANG Xinyi, WEN Shuai, HUANG Jian'an, LIU Zhonghua Journal of Tea Science    2023, 43 (5): 645-656.   DOI: 10.13305/j.cnki.jts.2023.05.003 Abstract （169）      PDF（pc） （2294KB）（144）       Knowledge map    Save EGCG is often regarded as the main active ingredient in tea to protect blood glucose homeostasis. The content of low molecular weight polyphenols such as EGCG in fungus fermented black tea (FFBT) is extremely low, and there are few studies on the hyperglycemic effect of FFBT. To explore the hypoglycemic effects and potential mechanisms of FFBT, GK rats with spontaneous hyperglycemic were given 280 mg·kg-1 FFBT extract (equivalent to 9 g of FFBT for daily human consumption) by gavage intervention. The study assessed the effects of FFBT on body weight, glucose homeostasis, regulatory factors related to glucose homeostasis, diabetic complications and liver transcription profiles in hyperglycemic rats. The results indicated that FFBT could obviously reduce the fasting blood glucose level and random blood sugar level of hyperglycemic rats, improve the abnormal glucose metabolism in hyperglycemic rats, maintain glucose homeostasis and alleviate the damage caused by diabetic complications in hyperglycemic rats. In addition, transcriptome analysis revealed that the hypoglycemic properties of FFBT might be related to the regulation of gene expression in the liver, such as Gck, Pklr, Pkm. This study found that FFBT may be a potential hypoglycemic functional beverage, providing a theoretical basis for the development and utilization of fermented tea such as FFBT. Reference | Related Articles | Metrics Select Glyphosate-stress Effects on Shikimic Acid in Tea Leaves LIU Hongxia, LIU Yingying, CHEN Hongping, CHAI Yunfeng Journal of Tea Science    2023, 43 (5): 657-666.   DOI: 10.13305/j.cnki.jts.2023.05.005 Abstract （191）      PDF（pc） （1058KB）（110）       Knowledge map    Save To investigate the effect of glyphosate stress on the growth and shikimic acid metabolism of tea (Camellia sinensis L.) plants, tea seedlings were cultured in nutrient solution with different concentrations of glyphosate and the visual phytotoxicity on tea leaves was observed. The non-targeted analysis of non-volatile metabolites in the leaves and quantitative determination of shikimic acid and glyphosate in the leaves were carried out by ultra-high performance liquid chromatography-quadrupole orbitrap high-resolution mass spectrometry. The results show that the tea seedlings under the high dose of glyphosate (200 mg·L-1) treatment exhibited characteristics of pesticide damage, while the tea seedlings under the low dose of glyphosate (50 mg·L-1) treatment and control did not show apparent pesticide damage. Mass spectrometric and statistical analysis indicates that there were significant changes in the contents of shikimic acid pathway metabolites in the leaves of glyphosate-treated tea seedlings, with shikimic acid being one of the main differential metabolites. Within 21 d, the accumulation of shikimic acid in leaves was highly positively correlated with the absorption amount and action time of glyphosate. When the absorption amount of glyphosate was larger than 28 mg·kg-1, the shikimic acid metabolism in tea plants was significantly inhibited, resulting in a large accumulation of shikimic acid in tea leaves. Compared with the control group, the content of shikimic acid in tea leaves affected by pesticides increased about 16-fold. This study shows that shikimic acid is one of the main metabolites of tea plants in response to glyphosate stress. Reference | Related Articles | Metrics Select Analysis of Aroma Characteristics and Volatile Components of Zhenghe White Tea with Different Storage Years HUANG Wei, ZHANG Lingzhi, ZHANG Jialin, LIN Fuming, RONG Jiefeng, XIAO Chunyan, YUE Penghang, YU Huazhu, SUN Weijiang, HUANG Yan Journal of Tea Science    2023, 43 (5): 667-680.   DOI: 10.13305/j.cnki.jts.2023.05.006 Abstract （274）      PDF（pc） （1492KB）（309）       Knowledge map    Save In order to investigate the aroma characteristics of Zhenghe white tea with different storage years, quantitative descriptive analysis (QDA) combined with headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) was used to analyze the aroma characteristics and volatile components of Zhenghe white peony tea stored for 0, 5, 10 and 15 years. The results show that the aroma characteristics of Zhenghe white peony tea varied significantly among different storage years. The aroma characteristics of BMD0 were mainly pekoe, fresh, sweet and floral. With the extension of storage time, the pekoe, fresh, sweet and floral weakened, while the stale flavour and woody increased. A total of 66 volatile components were detected in Zhenghe white peony tea with different storage years, mainly alcohols, esters and acids, with the highest alcohol content in BMD0 and BMD5, and the highest ester content in BMD10 and BMD15. With the extension of storage time, the total volatile components decreased significantly, and the composition and proportion of relative contents changed significantly. The Orthogonal partial least-squares discrimination analysis (OPLS-DA) model could effectively discriminate Zhenghe white peony tea with different storage years. A total of 14 volatile components were screened based on relative odor activity value (rOAV)>1, while 30 volatile components were screened based on variable importance for the projection (VIP)>1. Based on rOAV value>1 and VIP value>1, 6 major volatile components were screened, including β-ionone, α-ionone, nerolidol, benzyl alcohol, benzeneacetaldehyde, linolenic acid. This study provided a theoretical reference and basis for the scientific storage of white tea and the flavour analysis of aged white tea. Reference | Related Articles | Metrics Select Parameter Optimization of Black Tea Fermentation Machine Based on EDEM and RSM LIU Limin, DONG Chunwang, LIN Shuhong, SHI Yali Journal of Tea Science    2023, 43 (5): 681-690.   DOI: 10.13305/j.cnki.jts.2023.05.004 Abstract （125）      PDF（pc） （2472KB）（106）       Knowledge map    Save Fermentation is a key process for the formation of black tea quality, and the fermentation conditions are the important factors affecting the degree of fermentation. In order to optimize the parameters of a self-designed roller fermentation machine, the extended distinct element method (EDEM) was used to simulate three distinct gradients of the rotational speed of the flexible scraper, and compare the degree of uniformity. With sensory score as evaluation index, response surface method (RSM) was applied for optimizing three key factors affecting fermentation quality (fermentation temperature, fermentation time, stirring interval). The results indicate that the uniformity of fermentation was the best at a rotation speed of 36(°)·s-1. Based on this rotational speed, the order of importance of each factor on fermentation quality was: fermentation time, fermentation temperature, stirring interval. The optimal process parameters were as follows: fermentation time, 230βmin, fermentation temperature, 28.5β℃, and stirring interval, 20βmin. Reference | Related Articles | Metrics Select Exploratory Study on the Image Processing Technology-based Tea Shoot Identification and Leaf Area Calculation LÜ Danyu, JIN Zijing, LU Lu, HE Weizhong, SHU Zaifa, SHAO Jingna, YE Jianhui, LIANG Yuerong Journal of Tea Science    2023, 43 (5): 691-702.   DOI: 10.13305/j.cnki.jts.2023.05.007 Abstract （157）      PDF（pc） （2181KB）（91）       Knowledge map    Save In this study, based on the picture collection of tea shoot growth in the field, we used deep learning target detection algorithm YOLOv5 to construct a model for identifying different growth stages of tea shoots, and the testing results indicate that the model had high accuracy. Furthermore, the Image-J software and the image processing methods of threshold cutting based on Gray, RGB and HSV values were applied to process tea leaf area, and the accuracy and efficiency of different methods were compared. The results show that the accuracy of HSV-based algorithm system of cutting tea leaves and automatically calculating tea leaf area was over 94%, which had better performance than RGB-based algorithm system. The research results provide technical support for the intelligent recognition model of tea growth state and information extraction algorithm of leaf traits, and also build a theoretical basis for the development of tea bud automatic recognition module of tea plucking machinery. Reference | Related Articles | Metrics page Page 1 of 9 Total 259 records First page Prev page Next page Last page