Journal of Tea Science

Research Progress and Prospect of Green Control Techniques of Ectropis obliqua

LI Xiwang, LIU Fengjing, SHAO Shengrong, SU Liang, JIN Limeng, LOU Yonggen, SUN Xiaoling

Journal of Tea Science. 2017, 37(4): 325-331.

Abstract ( 309 )

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Ectropis obliqua is one of the most destructive insect pests on tea plantations. The tea plants could be eaten or even died when E. obliqua erupted. Recent years, the outbreaks of E. obliqua have occurred extensively in tea cultivation areas of many provinces in China, and had led to serious economic losses. The investigation on the species clarification, volatile attractants, sex pheromone identification and other control techniques of the E. obliqua have been proliferated over the past a few years. Based on summarizing the previous results and combining the developmental trend of the current pest management both here and abroad, the development directions of E. obliqua management are prospected in the current paper, in order to provide reference to scientific control of E. obliqua in tea plantations.

Research Progress of Green Tea and EGCG for the Prevention and Mitigation of Chronic Obstructive Pulmonary Disease Caused by Cigarette Smoke

HUANG Xiangxiang, YANG Zhe, YU Lijun

Journal of Tea Science. 2017, 37(4): 332-338.

Abstract ( 322 )

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Chronic obstructive pulmonary disease (COPD) is one of the most common diseases induced by cigarette smoking. Cigarette smoke-induced oxidative stress, inflammation response, proteases and anti-proteases imbalance are intimately associated with the occurrence and exacerbation of COPD. Green tea consumption and EGCG oral administration can scavenge reactive oxygen species and free radicals in the human body, and inhibit a series of respiratory diseases caused by reactive oxygen species and free radicals. In this article, the research advance of the effects of green tea and EGCG on COPD for the past 10 years was reviewed in the purpose of exploring the mechanism and improving public knowledge of the preventing effects of green tea and EGCG on COPD.

Study on Amino Acids Composition and Mineral Elements of Tea Hairs

SONG Yakang, ZHANG Qunfeng, ZHANG Jie, GAO Yaoyao, HU Jianhui

Journal of Tea Science. 2017, 37(4): 339-346.

Abstract ( 332 )

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The amount and density of tea hairs on made tea is an important indication to assess tea quality. To determine the chemical compositions of tea hairs, four tea samples rich in tea hairs, namely, Biluochun, Yunnan black tea, Baihao Yinzhen and Baimudan were used. Tea hairs was compared to the non-pubescent leaves. The contents of C, N and C/N, the composition and contents of amino acids, primary mineral elements were analyzed by elemental analyzer, automatic amino acid analyzer and ICP-OES respectively. The C and N contents in tea hairs ranged from 2.96% to 4.74% and 42.87% to 45.58%, respectively. The N contents in tea hairs were significantly lower than those in the non-pubescent leaf (P<0.01), while C/N showed an opposite trend and C contents showed no significant difference. Hydrolytic amino acids and free amino acid contents in tea hairs ranged from 10.78 % to 12.46% and 20.78βmg·g^-1 to 34.65βmg·g^-1, respectively. The major constituents and the total amount of hydrolytic amino acids and free amino acids in tea hairs were all significantly lower than those in tea body (P<0.05), with an exception of the ratio of theanine to total free amino acids (P<0.05). While the differences of the free amino acid constituents (theanine, asparagine, glycine, and γ-GABA) were not significant. The mineral elements in hairs were generally slightly lower than those in tea. Among them, the P and S contents showed the largest differences (P<0.01). In summary, the contents of amino acids and mineral elements in tea hairs are not higher than those in tea body, but the composition differences in quality constituents might contribute to the special quality characteristics.

Study on Multi-phase Distribution of Black Tea Infusion Taste Compounds

LIN Dai, LI Bingjie, ZHOU Jianwu, RAO Pingfan

Journal of Tea Science. 2017, 37(4): 347-355.

Abstract ( 369 )

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The black tea infusion was separated into three phases: suspension, colloid, and the true solution by microfiltration and ultrafiltration at different temperatures. Then the concentration and distribution proportion of caffeine, total polyphenols, amino acids, and total sugars were measured. The colloidal properties were measured by Malvern. According to the sensory evaluation and the changes in contents of theaflavin, thearubigins, theabrownin, the correlations between the distribution proportion of the taste compounds, the colloid properties and the flavor of tea infusion were established. The results revealed that the proportion of taste compounds in different phases of the tea infusion was significantly different at different temperature, and the proportion of colloid/true solution could affect the size, potential of the colloidal system and the flavor. The tea infusion acquired a best sensory score by microfiltration at 50℃, while the composition distributions of colloid and true solution were 1︰3.8 for caffeine, 1.2︰1 for total polyphenols, 1︰7.5 for amino acids and 1︰4.3 for total sugars. The average particle size was 160βnm, and the Zeta potential was -25.5βmV. The 50℃ filtrated tea was mellow, rich in aroma, stable, and had uniform particle size distribution.

Study on Physiological Response of Tea Plant (Camellia sinensis) Seedlings to Different Aluminum Concentrations

WANG Min, NING Qiuyan, SHI Yuanzhi

Journal of Tea Science. 2017, 37(4): 356-362.

Abstract ( 265 )

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This study was to investigate the physiological response of tea cultivar Longjing 43 seedlings to different aluminum (Al) concentrations by hydroponic culture. The results revealed the biomass increment, relative growth rate (RGR) and electron transfer efficiency (ETR) of the tea plants under low Al concentrations (0.2 and 0.4βmmol·L^-1) were significantly higher than the control group. However, The MDA content in roots showed an opposite trend. As Al concentration continued to increase, the increase rate of ETR began to decline and the growth rate became flat but still a great number of fresh roots were coming up. When Al concentration was higher than 1βmmol·L^-1, the efficiency of light energy conversion in PSⅡ(Fv/Fm) and ETR showed dramatic decline. Meanwhile, RGR decreased and the growth of tea plant was also inhibited. Simultaneously, the results of Al contents in the different tissues of tea plants followed lateral roots, mature leaves > stems > main roots > young leaves. More Al was found in the lateral roots with Al concentration increasing. The study suggested that when Al concentration was lower than 1.0βmmol·L^-1, it could promote the growth of tea plants, but the growth would be inhibited under an Al-free environment or the Al concentration was higher than 1 mmol·L^-1. These results laid a foundation for further study on the physiological mechanism of how Al would promote the growth of tea plants.

Effects of Chlorophyll Fluorescence Parameters of Different Tea Cultivars in Response to Low Nitrogen

LIN Zhenghe, ZHONG Qiusheng, HAO Zhilong, YOU Xiaomei, CHEN Zhihui, CHEN Changsong, SHAN Ruiyang, RUAN Qichun

Journal of Tea Science. 2017, 37(4): 363-372.

Abstract ( 362 )

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Chlorophyll fluorescence parameters are often used to evaluate stress status and plant physical response to stresses. To explore guidelines for nitrogen fertilization, nitrogen deficiency degree should be measured and estimated sensitively. Therefore, items including individual plant dry matter, nitrogen content and fluorescence parameters of leaves were measured among tea cultivars with different nitrogen use efficiencies. The dry matter of roots, stems, leaves and nitrogen content in leaves were declined sharply under low nitrogen stress. Compared with the low nitrogen sensitive tea cultivar ‘Benshan’, the root, stem and leaf dry weights (DW) of ‘Huangdan’ were higher under low nitrogen stress. Fo, Y(NPQ), non-photochemical quenching coefficients (NPQ) and Y(NO) increased under low nitrogen, and the fluorescence parameters of ‘Benshan’ under low nitrogen were higher than Huangdan. The maximum (Fm), primary maximum photochemical efficiency of PSⅡ(F_v/F_m), actual photosynthetic efficiency Y(Ⅱ) and coefficient of photochemical quenching (qP and qL) decreased under low nitrogen, and the fluorescence parameters of ‘Benshan’ under low nitrogen were lower than those of ‘Huangdan’. The relative high nitrogen-utility tea cultivar can reduce the damage caused by the low nitrogen stress and maintain a relatively high photosynthetic efficiency. Therefore, tea cultivar with relative high nitrogen-utility had higher yields than cultivar with low nitrogen-utility under low nitrogen stress.

The Evaluation of the Stability of EGCG-Selenium Nanoparticles and Its Effect on Selenium Absorption and Utilization

WANG Le, LI Huan, LI Jiahao, CHEN Xuan, LI Xinghui, SUN Kang

Journal of Tea Science. 2017, 37(4): 373-382.

Abstract ( 517 )

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(-)-epigallocatechin-3-gallate (EGCG) dispersed Selenium nanoparticles (EGCG-SeNPs) were prepared using vitamin C (Vc) and EGCG as the redox agent and dispersant. Characteristics of EGCG-SeNPs, which were determined using transmission electron microscope (TEM) and zetasizer, were spherical in shape with a mean diameter of (35±0.12)βnm and -0.05βmV zeta potential. The particles were aggregated in strong acid and high temperature conditions (pH1.0 and 70℃), with the particle size increased by about 10 times. And, EGCG in EGCG-SeNPs had good stability as a dispersant. With the administration of 25, 50 and 100βμg·kg^-1 (Calculated with selenium content), selenium content in liver and kidney of 50 and 100βμg·kg^-1 sodium selenite and EGCG-SeNPs treated mice were significantly increased. Glutathione peroxidase (GPx) activity in serum, liver and kidney of all the treatment groups were significantly increased in a dose-dependent manner. However, there was no significant difference between sodium selenite and EGCG-SeNPs at the same dose on selenium content and GPx activity. Hence, it can be concluded that EGCG-SeNPs synthesized using Vc as the redox agent might have the similar bioavailability to sodium selenite.

The Effects of Nitrogen Supply on Agronomic Traits and Chemical Components of Tea Plant

LI Hailin, WANG Liyuan, CHENG Hao, WEI Kang, RUAN Li, WU Liyun

Journal of Tea Science. 2017, 37(4): 383-391.

Abstract ( 417 )

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In this study, the effects of nitrogen supply on the important agronomic traits and chemical components were analyzed in 4 tea varieties using Longjing 43 as control. The results showed that sufficient nitrogen application effectively increased the tea yields by changing some key agronomic traits, such as increasing the chlorophyll content in mature leaves, accelerating the germination and growth of new shoots and increasing the density of germination. Meanwhile, nitrogen application affected the metabolisms of main chemical components (theanine, caffeine and polyphenols) in tea plant, resulting in the improvement of tea quality. The Zhongming 22 and LY002 showed more sensitive responses to high nitrogen application. These results provide important backgrounds for breeding of tea cultivars with higher nitrogen use efficiency.

Toxicity Assessment of Insecticides to Three Common Piercing-sucking Insects in Tea Plantations

WANG Yao, MU Wei, ZHANG Lixia, XU Yongyu, LIN Jin, ZHANG Zhengqun

Journal of Tea Science. 2017, 37(4): 392-398.

Abstract ( 440 )

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Matsuda （Empoasca onukii）, Quaintance （Aleurocanthus spiniferus） and Boyer （Toxoptera aurantii） are three most common piercing-sucking insects in tea plantations, which severely reduce tea production and quality. Chemical control is one of the most important strategies in control of these tea pests. In order to screen high-efficient insecticides, the toxicities of 16 insecticides of ten different classes to the nymphs of three tea pests were evaluated under laboratory conditions. The results of toxicity tests showed that tolfenpyrad, emamectin, indoxacarb and chlorfenapyr showed the highest toxicities to the E. onukii nymphs, with the 24βh LC₅₀ values of 0.23, 0.52, 0.94βand 5.24βmg·L^-1, respectively. Cyantraniliprole, chlorantraniliprole, clothianidin and spirotetramat were four most toxic compounds for the A. spiniferus nymphs, with the 24βh LC₅₀ values of 0.15, 0.26, 0.41 and 0.66βmg·L^-1, respectively. Except for dinotefuran and indoxacarb, other fourteen tested insecticides showed high toxicities to the T. aurantii nymphs, with the 24βh LC₅₀ values below 10βmg·L^-1. The results of this study laid a foundation for selecting and applying insecticides according to the target pests, and also promoting the reduction of pesticides used in tea plantations.

Cloning and Expression Analysis of CsASR Gene in Tea Plant (Camellia sinensis)

YUE Chuan, CAO Hongli, HAO Xinyuan, GUO Yuqiong, YE Naixing, WANG Xinchao, YANG Yajun

Journal of Tea Science. 2017, 37(4): 399-410.

Abstract ( 302 )

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Abiotic stress severely affects the growth and development of tea plant and the quality of tea. ASR (abscisic acid, stress, ripening) genes play crucial roles in the plant response to stresses. The full-length cDNA, genomic sequence and the promoter sequence of CsASR gene were cloned from tea cultivar Longjing 43 in this study, The bioinformatic and the expression analysis of CsASR in tissues under different stress treatments were performed. The results revealed that the full-length cDNA of CsASR was 875βbp, containing a 546βbp ORF encoding 181 amino acid. The predict protein molecular and theoretic isoelectric point of CsASR were 19.89βkD and 5.69. Most regions of the amino acid sequence (74.5%) were predicted as the non-ordered regions, indicating that CsASR is a disordered protein. C-terminal of CsASR contained an ABA/WDS functional domain which was primarily located in both the cytoplasm and the nucleus. The homologous alignment and phylogenetic tree analysis showed that CsASR had the highest similarity (87%) with Phoenix dactylifera, and had the closest genetic relationship with Ziziphus nummularia. The genomic sequence of CsASR gene was comprised by two exons with 363 bp and 183 bp in length, respectively, and had a 2 750 bp intron which contained seven simple repeats and two DNA transposons. The promoter sequence of CsASR was 2 554 bp in length and was predicted to contain several stress-responsive elements related to drought, cold, high temperature stresses and ABA-signaling. The expression analysis showed that CsASR had the lowest level in roots, and its expression was repressed by ABA treatment. While the drought, NaCl and cold stresses could significantly up-regulate the expression of CsASR. The results revealed that CsASR might be closely related to stress response in tea plant.

Cloning and Expression Analysis of WRKY Transcription Factor Gene CsWRKY57 in Tea Plant (Camellia sinensis)

GUO Junhong, WANG Weidong, GU Xing, GUO Shasha, GAO Yuefang, YANG Yajun, XIAO Bin

Journal of Tea Science. 2017, 37(4): 411-419.

Abstract ( 341 )

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The WRKY is one of the characteristic transcription factors in plants, which play important roles in plant growth, development and stress regulation. In order to study the relationship between WRKY transcription factors and stress tolerance of tea plant (Camellia sinensis), a WRKY transcription factor was cloned from tea cultivar ‘Shanchayihao’ and named CsWRKY57, based on the searching result of tea plant transcriptome database. Bioinformatics analysis showed that the full-length sequences of CsWRKY57 was 1β222βbp encoding 303 amino acids. The molecular weight of CsWRKY57 was 33.5βkD and theoretical isoelectric point was 5.49. The BLAST results showed that CsWRKY57 contained one typical WRKY domain and one zinc finger motif (C2H2), suggesting that it was a member of the WRKYIIc family. In addition, quantitative real-time PCR (qRT-PCR) analysis showed that the expression of CsWRKY57 was induced by salt, drought and ABA stresses, and showed a tendency to increase first and then decrease, which implies that CsWRKY57 is involved in the process of tea plant responses to salt, drought and ABA. Furthermore, transcriptional activation activity assays indicated that CsWRKY57 didn't have transcriptional activation activity, which means that CsWRKY57 may be needed to combine with other elements to activate gene expression.

A Glimpse into Contemporary “U.S. Tea Renaissance”

SHENG Min, LIU Zhonghua, HUANG Jian′an, XIAO Lizhen, ZHU Haiyan

Journal of Tea Science. 2017, 37(4): 420-427.

Abstract ( 380 )

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Tea, a magical oriental leaf, had played an important role in the recent period of American history. “The Boston Tea Party” led to the beginning of American Independence War. The time of “Clippers” achieved the summit of American ship building industry in the recent period. Tea had become the top trade between America and China in the recent period. Once American people had followed the trend of tea-drinking in the seventeenth and eighteenth centuries in the Europe, but were laughed by British people for American’s never identifying tea or knowing how to drink tea. Therefore, tea sold in the U.S. was mainly the low and medium grade. With the promotion and development of “Specialty Tea”, American people have become to learn how to identify and drink tea since 1980s. “The U.S. Tea Renaissance” is coming, and the trend has changed the concept of tea-drinking and tea industry in the U.S. Besides, American people has conveyed the passion of tea-drinking to the people all over the world and begun to lead a worldwide trend.

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