Method for regulating and controlling quality of Dancong ancient tree tea

Abstract

The invention relates to the technical field of tea tree cultivation, in particular to a method for regulating and controlling the tea quality of a Dancong ancient tree. According to the regulation and control method, soil diversity of the single-bush ancient tea garden is regulated and controlled, soil elements of the single-bush ancient tea garden are enriched, soil fertility of the single-bush ancient tea garden is improved, tea leaf secondary metabolites of the single-bush ancient tea garden are improved, contents of fresh tea leaves are adjusted by adjusting the soil elements, and contents and volatile substances of the fresh tea leaves are adjusted by adjusting elements of the fresh tea leaves. The quality of tea in the tea garden is effectively and accurately controlled, and high quality and high yield of Dancong tea are promoted.

Description

Technical Field

[0001] The invention relates to the technical field of tea tree cultivation, and in particular to a method for regulating the quality of tea leaves from single-bush ancient trees. Background Art

[0002] Ancient tea trees refer to wild ancient tea trees and their communities distributed in natural forests, semi-domesticated wild tea trees, or tea trees in ancient tea gardens that have been cultivated for more than 100 years.

[0003] Fenghuang tea area in Chaozhou City, Guangdong Province has rich and diverse ancient tea tree resources, with trees as old as hundreds of years. These provide valuable materials for the study of soil acidification, continuous nutrient changes and their relationship with tea quality in tea gardens. Single-bush ancient tea trees are different from general ancient trees. Solving the supply and demand relationship of nutrients in ancient tea trees is the key to prolonging their vigorous life. In recent years, some scholars have also confirmed that the suitable soil pH value for ancient tea trees is 4.00-6.09. Compared with modern tea gardens, the soil acidification trend of ancient tea gardens is not obvious. At the same time, the content of organic matter, available nitrogen and available phosphorus in the soil of ancient tea gardens is higher than that of modern tea gardens. In addition, the complex community structure and ecological environment of ancient tea gardens enable their soil fertility to maintain itself better. Ancient tea gardens have very important economic value and cultivation value. Therefore, it is particularly important to carry out the analysis of soil microorganisms, soil fertility and fresh tea leaf quality component characteristics in ancient tea gardens, and the comprehensive evaluation of soil and fresh tea leaves in ancient tea gardens for the development, utilization and cultivation management of ancient tea trees. Summary of the invention

[0004] The purpose of the present invention is to avoid the shortcomings of the prior art and provide a method for regulating the quality of single-bush ancient tree tea, which can better control the quality of single-bush ancient tree tea by measuring and regulating the rhizosphere soil microbial diversity, soil physical and chemical properties, soil element content, and the content of fresh tea leaf elements, internal substances and volatile substances.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A method for regulating the quality of tea leaves from ancient single-bush trees is provided, the method comprising any one of the following methods:

[0007] Regulate soil diversity in single-bush ancient tea gardens;

[0008] Enriching soil elements in single-bush ancient tea gardens;

[0009] Improve soil fertility in single-bush ancient tea gardens;

[0010] Improve the secondary metabolites of tea leaves in single-bush ancient tea gardens;

[0011] Adjust the contents of fresh tea leaves by adjusting the soil elements;

[0012] The content and volatile substances in the fresh tea leaves are adjusted by adjusting the elements in the fresh tea leaves.

[0013] In some embodiments, the step of regulating soil diversity in a single-bush ancient tree tea garden comprises:

[0014] The soil bacterial diversity was improved by adjusting the pH value, total nitrogen, alkaline-hydrolyzed nitrogen and total potassium in the soil of the single-bush ancient tree tea garden. Among them, the pH value, total nitrogen content, alkaline-hydrolyzed nitrogen content and total potassium content in the soil of the single-bush ancient tree tea garden were positively correlated with the soil bacterial diversity.

[0015] By increasing the pH value, total nitrogen content, alkaline nitrogen content and total potassium content in the soil, the diversity of soil bacteria can be effectively improved, thereby promoting the effect of soil bacteria on the growth of tea trees.

[0016] In some embodiments, the bacterial diversity of the single-bush ancient tree tea garden includes:

[0017] The top three bacterial phyla in the rhizosphere soil of the single-bush ancient tea garden were Proteobacteria, Acidobacteria, Chloroflexi, and Actinobacteria.

[0018] The top three fungal phyla in the rhizosphere soil of the single-bush ancient tea garden were Basidiomycota, Ascomycota and Mortierella.

[0019] The dominant bacterial genera in the soil of the single-bush ancient tea garden were Subgroup_2, AD3, Thermoacidobacterium, Acidobacterium, Rhizobium, and Bradyrhizobium;

[0020] The dominant bacterial genera in the rhizosphere soil of the single-bush ancient tree tea garden are Salamander, Mortierella and Fusarium.

[0021] In some embodiments, the step of enriching soil elements in a single-bush ancient tree tea garden comprises:

[0022] Enrich the soil with Ca, Mg, Fe, Al, Mn, Ba, Co, Mo and Ti elements by increasing the level of alkaline nitrogen and organic matter in the soil.

[0023] By increasing the level of alkaline nitrogen and organic matter in the soil, the tea trees can be promoted to enrich and absorb Ca, Mg, Fe, Al, Mn, Ba, Co, Mo and Ti elements, which is beneficial to improving the growth of the tea trees.

[0024] In some embodiments, the step of improving soil fertility in a single-bush ancient tree tea garden comprises:

[0025] When the soil fertility of a single-bush ancient tree tea garden is lower than level I, the soil fertility can be improved by applying potassium fertilizer.

[0026] The application of potassium fertilizer can improve the soil fertility of single-bush ancient tree tea gardens, and has the advantage of good improvement effect.

[0027] In some embodiments, the step of increasing the secondary metabolites of tea leaves in a single-bush ancient tea garden comprises:

[0028] By increasing the pH value of the soil in the single-bush ancient tea garden, the catechin content of tea leaves can be increased.

[0029] The content of theanine in tea leaves can be increased by increasing the available potassium in the soil of single-bush ancient tea gardens.

[0030] In some embodiments, the step of regulating the contents of fresh tea leaves comprises:

[0031] The caffeine content in tea leaves was controlled by adjusting the alkaline nitrogen level, total nitrogen level and organic matter level in the soil. Among them, the alkaline nitrogen level, total nitrogen level and organic matter level in the soil were negatively correlated with the caffeine content.

[0032] The substances contained in fresh tea leaves are controlled by adjusting the elements Mg, V, Ta, Sn, Li, Zr, Mn, Ti and Cr in the soil. Among them, Mg, V, Ta, Sn, Li and Zr are positively correlated with the substances contained in fresh tea leaves, while Mn, Ti and Cr are negatively correlated with the substances contained in fresh tea leaves.

[0033] In some embodiments, the top seven volatile substances in the fresh tea leaf contents are linalool, linalool acetate, trans-2-hexenal, geraniol, methyl salicylate, linalool oxide I and linalool oxide II.

[0034] In some embodiments, the tea leaves of the single-bush ancient tea garden are resistant to insects using geraniol, trans-2-hexenal and methyl salicylate substances.

[0035] In some embodiments, the step of adjusting the types of substances and volatile substances contained in the fresh tea leaves by adjusting the elements of the fresh tea leaves comprises:

[0036] The substances contained in fresh tea leaves can be increased by increasing the elements N, P, Mg, Zn, Ca, Sn and Ni in fresh tea leaves, and the aroma components of fresh tea leaves can be increased by increasing the elements Sr, Al, K, Si, V, Ni and Zr in fresh tea leaves.

[0037] Beneficial effects of the present invention:

[0038] The method for regulating the quality of tea leaves from single-bush ancient tree tea gardens of the present invention effectively and accurately controls the quality of tea leaves in tea gardens by regulating soil diversity in single-bush ancient tree tea gardens, enriching soil elements in single-bush ancient tree tea gardens, improving soil fertility in single-bush ancient tree tea gardens, improving secondary metabolites of tea leaves in single-bush ancient tree tea gardens, adjusting the contents of fresh tea leaves by adjusting soil elements, and adjusting the contents and volatile substances of fresh tea leaves by adjusting fresh tea leaf elements, thereby promoting high-quality and high-yield single-bush tea. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 OTUVern diagram of rhizosphere soil microorganisms in a single-bush ancient tea garden: (a): bacteria, (b): fungi.

[0040] Figure 2 OTU rarefaction curves of rhizosphere soil microorganisms in single-bush ancient tea gardens (a): bacteria, (b): fungi.

[0041] Figure 3 PCoA analysis of rhizosphere soil microorganisms in single-bush ancient tea gardens (a): bacteria, (b): fungi.

[0042] Figure 4 NMDS analysis of rhizosphere soil microorganisms in single-bush ancient tea gardens (a): bacteria, (b): fungi.

[0043] Figure 5 Relative abundance of major bacterial phyla in rhizospheric soil bacterial communities in single-bush ancient tea gardens.

[0044] Figure 6 Relative abundance of major bacterial phyla in rhizospheric soil fungal communities in single-bush ancient tea gardens.

[0045] Figure 7 Relative abundance of major bacterial genera in rhizosphere soil bacterial communities in single-bush ancient tea gardens.

[0046] Figure 8 Relative abundance of major genera in rhizospheric soil fungal communities in single-bush ancient tea gardens.

[0047] Fig. 9 Cluster heat map analysis of the main bacterial genera in the rhizosphere soil of single-bush ancient tree tea garden.

[0048] Fig.10 Cluster heat map analysis of the main fungal genera in the rhizosphere soil of single-bush ancient tree tea garden.

[0049] Fig.11 Comparative analysis of soil elements in different single-bush ancient tea gardens Note: Different lowercase letters indicate significant differences at the P<0.05 level (n=3).

[0050] Fig.12 Geoaccumulation index of metal elements in topsoil of tea gardens.

[0051] Fig.13 Geoaccumulation index of metal elements in subsurface soil of tea gardens.

[0052] Fig.14 Metal element enrichment factors in tea garden surface soil.

[0053] Fig.15 Metal element enrichment factors in subsurface soil of tea gardens.

[0054] Fig.16 Single factor index of metal elements in tea garden surface soil.

[0055] Fig.17 Single factor index of metal elements in subsurface soil of tea garden.

[0056] Fig.18 Nemerow comprehensive contamination index of metals in topsoil of tea gardens.

[0057] Fig.19 Nemerow comprehensive pollution index of metals in subsurface soil of tea gardens.

[0058] Fig. 20 Potential ecological risk index of individual heavy metals in the surface soil of tea gardens.

[0059] Fig.21 Potential ecological risk index of individual heavy metals in the sub-surface soil of tea gardens Figure 16 Statistical results of the potential ecological risk index of metal elements in the surface soil.

[0060] Fig. 22 Comparative analysis of substances contained in fresh leaves from different tea gardens Note: Different lowercase letters indicate significant differences at the P<0.05 level (n=3).

[0061] Fig.23 Biplot of principal component analysis of volatile components in fresh leaves. DETAILED DESCRIPTION

[0062] Preferred embodiments of the present invention will be described in more detail below with reference to the accompanying drawings.

[0063] In order to better illustrate the implementation method of the embodiment, the materials and detection methods are described.

[0064] Materials and Methods

[0065] 1Material collection and pretreatment

[0066] The sample collection time for this article was April 2022. According to the requirements of the "Technical Specifications for Soil Environmental Monitoring" (HJ / T166-2004), in the Fenghuang production area of ​​Chaozhou City, Guangdong Province, ancient tea trees with an age of more than 100 years were selected from four ancient tea gardens (Zimao ZMF, Baixiang BX, Xialiao HSK, and Da'an DAF). Tea trees with uniform height, uniform canopy width, and no signs of diseases and insect pests were selected for the experiment. Leaves with one bud and three leaves of the mature leaf-to-leaf maturity were picked from the ancient tea trees (refer to the position of the top bud), and about 250g of samples were collected. The surface attachments were removed and placed in polyethylene bags. All samples were immediately frozen in liquid nitrogen and then kept at -80℃.

[0067] The soil of the surface layer (0-20cm) and the sub-surface layer (20-40cm) near the roots of the ancient tea trees were collected, and the rhizosphere soil of the tea trees at the corresponding depth was collected at the same time. After the soil samples at each sampling point were mixed, impurities such as stones, roots, leaves, and insect bodies were removed. About 1kg of soil samples were taken by the quartering method and placed in polyethylene bags. The samples were spread on white paper indoors to air dry naturally, and the fine roots and stones of the plants were picked out, ground with a wooden stick, and passed through a nylon sieve for later use. The collected rhizosphere soil of the tea trees was immediately frozen in liquid nitrogen and then kept at -80℃.

[0068] Table 1 Geographical distribution of different ancient tea gardens

[0069]

[0070] 2.2.1 Determination of soil physical and chemical indicators

[0071] The soil pH value shall refer to the HJ962-2018 method, the soil organic matter shall refer to the NY / T1121.6-2006 method, the soil alkaline nitrogen shall refer to the DB51 / T1875-2014 method, the soil available phosphorus shall refer to the HJ704-2014 method, the soil available potassium shall refer to the NY / T889-2004 method, the soil total nitrogen shall refer to the NY / T1121.24-2012 method, the soil total phosphorus shall refer to the HJ632-2011 method, and the soil total potassium shall refer to the NY / T87-1988 method.

[0072] 2.2.2 Extraction and determination of all elements

[0073] 2.2.2.1 Sample pretreatment

[0074] Soil sample: Accurately weigh 0.10000g (±0.00005) soil sample, add 5mL of 50% nitric acid, 5mL of hydrofluoric acid, 10mL of perchloric acid, boil at 300℃ until almost dry, then add 10mL of 50% nitric acid, heat until clear, dilute to 100mL, accurately transfer 10mL of the liquid after dilution to a 100mL volumetric flask, this is the liquid to be tested. Fresh leaf sample: Accurately weigh 0.50000g (±0.00005) tea sample, add 10mL of 50% nitric acid, let it stand for more than 8h to exhaust after adding, boil at 100℃ until almost dry, then add 10mL of 50% nitric acid, continue heating until clear, dilute the solution to a 50mL volumetric flask, this is the sample to be tested.

[0075] 2.2.2.2 Preparation of standard solution and sample determination

[0076] Preparation of mixed standard solution: A certain amount of single standard or mixed standard stock solution is diluted stepwise with 5% nitric acid to prepare the following 6 sets of standard solutions:

[0077] A: Na100μg / ml, 10μg / ml, 1μg / ml, 100ng / ml, 10ng / ml B: Ca100μg / ml, 10μg / ml, 1μg / ml, 100ng / ml, 10ng / ml

[0078] C: La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y: 100μg / ml, 10μg / ml, 1μg / ml, 100ng / ml, 10ng / ml

[0079] D: Zr, Nb, Mo, W, Hf: 100μg / ml, 10μg / ml, 1μg / ml, 100ng / ml, 10ng / ml E: Si: 100μg / ml, 10μg / ml, 1μg / ml, 100ng / ml, 10ng / ml

[0080] F: Al, As, B, Ba, Be, Bi, Co, Cr, Cu, Fe, Ga, Li, Mn, Mg, Ni, Pb, Sn, Sr, Ti, V, Zn: 100μg / ml, 10μg / ml, 1μg / ml, 100ng / ml, 10ng / ml

[0081] Preparation of standard curve working solution: ignite the plasma, wait for the instrument to preheat for 20 minutes, use tuning solution to adjust the instrument sensitivity, oxide, double charge, resolution and other indicators to make the instrument meet the measurement requirements, select relevant interference elimination methods, and introduce the above 6 sets of standard solutions online through the three-way.

[0082] 2.2.4 Determination of elements, internal substances and volatile substances in fresh leaves

[0083] 2.2.3.1 Determination of elements and substances contained in fresh leaves

[0084] The nitrogen, phosphorus and potassium elements in fresh leaves were determined according to the NY / T2017-2011 method, and the caffeine, catechin and theanine contents were determined by high performance liquid chromatography (HPLC) according to the method of Chen Peifen et al. (Chen et al., 2022).

[0085] 2.2.3.2 Determination of volatile substances in fresh leaves

[0086] (1) HS-SPME extraction of volatile components of tea

[0087] The volatile substances of tea leaves were extracted by headspace solid phase microextraction. For the extraction of volatile substances of finished tea, 2.0g tea sample was matched with 40mL headspace bottle. For the extraction of volatile substances of fresh tea leaves, 0.2g tea sample was matched with 20ml headspace bottle. Among them, the fresh tea leaves had been ground into tea powder under liquid nitrogen conditions and stored at -80℃ for use.

[0088] Tea powder, 5 mL of saturated sodium chloride solution and 86.4 ng of ethyl caprate were added to the headspace bottle and quickly sealed. Divinylbenzene / carboxyl / polydimethylsiloxane fiber (inner diameter 50 / 30 μm, length 2 cm) was preheated at 80°C for 15 min, inserted into the headspace bottle, and extracted for 40 min. After extraction, the SPME fiber was placed in the inlet of the gas chromatograph and analyzed at 250°C for 3 min. Each sample was repeated 3 times.

[0089] (2) GC-MS analysis

[0090] GC-MS analysis was performed on an Agilent 1890B gas chromatograph and 5977A mass spectrometer. The HP-5MS capillary column (30m×0.25mm×0.25um film thickness) used high-purity helium as the carrier gas with a flow rate of 1.0mL / min in splitless mode. The heating program was to maintain the initial temperature at 50°C for 1min, then increase to 220°C at a rate of 5°C / min and maintain for 5min. The mass spectrometer ion source temperature was set to 230°C and the electron energy was set to 70eV. The scanning range was 30-400 atomic mass units (amu) and the solvent delay time was 4min. Each sample was repeated 3 times.

[0091] (3) Qualitative and quantitative

[0092] For the qualitative analysis of volatile components, the retention index (RI) and mass spectrometry matching factor are used for screening. That is, when the difference between the calculated RI value of the substance and the RI value of the substance provided in the NIST11 database is less than 15, and the mass spectrometry matching factor of the substance is greater than 90, the substance can be qualitatively identified. The RI value is calculated by separating and detecting the standard sample of the normal alkane mixture with carbon atoms ranging from 9 to 21 under the same heating program, obtaining the peak time of each alkane, and combining the peak time of the volatile component, using the following formula to calculate the retention index:

[0093]

[0094] Where RT(x) is the peak time (min) of volatile x, RT(n) and RT(n+1) are the peak times (min) of alkanes with carbon numbers n and n+1, and the peak time of volatile x should be between the peak times of carbon n and carbon n+1.

[0095] Example

[0096] Analysis on diversity of rhizosphere soil microbial communities in single-bush ancient tea gardens

[0097] OTU map of rhizosphere soil microorganisms in tea gardens. The classification results are as follows: Figure 1 (a) As shown. A total of 43,556 bacterial OTUs were detected in all samples. A total of 906 OTUs were found in the four tea garden samples, accounting for different proportions of the total OTU number in each sample, accounting for 6.87% of the OTU number in ZMF (13,192), 6.42% of the OTU number in BX (14,113), 6.46% of the OTU number in HSK (14,033), and 7.28% of the OTU number in DAF (12,452). The number of unique OTUs in ZMF was 9,793, BX was 9,774, HSK was 9,020, and DAF was 8,124, accounting for 74.23%, 69.26%, 64.28%, and 65.24% of the OTU number in each sample, respectively. These data show that the proportion of unique species in rhizosphere soil bacteria in ZMF tea garden is the highest. The number of bacterial OTUs was the highest in the rhizosphere soil of the BX tea garden, and the lowest in the rhizosphere soil of the DAF tea garden.

[0098] By analyzing the fungal OTUs in the rhizosphere soil of different ancient tea gardens, the classification results are as follows Figure 1 (b) As shown. A total of 5049 fungal OTUs were detected in all samples. There were 135 OTUs in the four tea garden samples, accounting for different proportions of the total OTU number in each sample, accounting for 10.01% of the OTU number in ZMF (1349), 7.52% of the OTU number in BX (1796), 9.57% of the OTU number in HSK (1411), and 6.77% of the OTU number in DAF (1994). The number of unique OTUs in ZMF was 900, the number of unique OTUs in BX was 1125, the number of unique OTUs in HSK was 723, and the number of unique OTUs in DAF was 1308, accounting for 66.72%, 62.64%, 51.24%, and 65.60% of the OTU number in their respective samples, respectively. These data also show that the proportion of unique species in the rhizosphere soil fungi of ZMF tea garden is the highest. The number of fungal OTUs was the highest in the rhizosphere soil of the DAF tea garden, and the number of bacterial OTUs was the lowest in the rhizosphere soil of the ZMF tea garden.

[0099] The number of bacterial OTUs in the soil was the highest in ZMF, followed by BX and HSK, and the number of OTUs in DAF was the lowest. The number of fungal OTUs in the soil was the opposite, with DAF having the highest number of OTUs and ZMF having the lowest number of OTUs.

[0100] 3.1.2 Rarefaction curve

[0101] Figure 2 The rarefaction curves of different sampling points are shown in Figure 1. When the curve tends to be flat as the number of extracted sequences increases, it means that the amount of sequencing data of the sample is reasonable. The curve in the figure rises first and then tends to be flat, indicating that the abundance of soil samples is high and the amount of sequencing data is reasonable, and the sequencing data can cover most of the bacterial information in the sample. The rarefaction curve of fungi shows a trend of rising first and then tending to be flat, indicating that the amount of sequencing data of the sample is also reasonable, and the sequencing data can cover most of the fungal information in the sample.

[0102] 3.1.3 Soil microbial alpha diversity

[0103] Table 3 shows the Alpha diversity index of bacteria in soil at different sampling points, which can detect the richness and diversity of soil bacteria in tea gardens. The observed species and Chao1 index reflect the richness of samples and are widely used in ecology (Wang et al., 2019; Xue et al., 2024). The richness index value of BX soil sample is the highest, followed by HSK and DAF, and the richness index value of ZMF is the lowest. Shannon index, Simpson index and Pielou index reflect the richness and uniformity of samples. The larger the Shannon index value, Simpson index value and Pielou index value, the higher the community diversity.

[0104] Among the four ancient tea gardens, the Alpha diversity of DAF is better than that of other tea garden sampling points. In the table, the Shannon index and Pielou index of DAF are the highest, which indicates that the soil bacterial diversity of DAF is higher. HSK and BX are followed, and the Shannon index and Pielou index of ZMF are the lowest, which indicates that the soil bacterial diversity of ZMF is the lowest.

[0105] Table 4 shows the Alpha diversity index of fungi in soil at different sampling points. The richness index value of soil samples from DAF was the highest, followed by BX and HSK, and the richness index value of ZMF was the lowest. Shannon index, Simpson index and Pielou index reflect the richness and uniformity of samples. The larger the Shannon index, Simpson index and Pielou index, the higher the community diversity. DAF had the highest Shannon index, Simpson index and Pielou index, which indicated that the soil fungal diversity of DAF was high.

[0106] Table 3 Bacterial α diversity index in rhizosphere soil of single-bush ancient tea garden

[0107]

[0108] Table 4 Fungal α diversity index in rhizosphere soil of single-bush ancient tea garden

[0109] 3.1.4 Soil microbial Beta diversity

[0110] Figure 3 (a) Bray-Curtis principal coordinate analysis (PCoA) of soil bacteria. PCoA analysis was performed on all treatments, with axis 1 values ​​of 18.4% and axis 2 values ​​of 16.2%. The closer the projection distance between two points on the coordinate axis, the more similar the community composition of the two samples in the corresponding dimension. Axis 1 can distinguish the difference between BX and DAF tea gardens, and axis 2 can distinguish the difference between ZMF and DAF tea gardens. ZMF's value is farthest from other treatments, indicating that the bacteria in its soil are most different from those in other tea gardens. BX and HSK have a high overlap rate. Figure 4 (a) The Jaccard algorithm of NMDS is used for bacteria, and the stress value is 0.0891. BX, ZMF, and DAW can be clearly distinguished. The overlap rate of BX and HSK is high. Figure 3 (b) Bray-Curtis principal coordinate analysis (PCoA) for fungi. PCoA analysis of all treatments showed that axis 1 had a value of 22.7% and axis 2 had a value of 9.4%. Axis 1 distinguished the differences between ZMF and DAF tea gardens, while axis 2 distinguished the differences between ZMF and HSK tea gardens. The overlap between BX and HSK was high. Figure 4 (b) The Jaccard algorithm of NMDS is used for fungi, and the stress value is 0.139. The overlap rate of BX, HSK and DAF is high. BX, ZMF and DAW can be clearly distinguished.

[0111] 3.1.5 Structure and composition of soil bacterial and fungal communities at the phylum level

[0112] At the phylum classification level, sequencing analysis detected the presence of fungal phyla such as Figure 6As shown in the figure, the dominant fungi in the soil are: Basidiomycota (26.75%-66.93%), Ascomycota (15.61%-45.98%) and Mortierellomycota (4.32%-12.01%), with an abundance of more than 10%. These three fungi are the dominant fungi in the ancient tea garden. Rozellomycota, Glomeromycota, Chytridiomycota, Mucoromycota, Olpidiomycota, Zoopagomycota, Kickxellomycota, Basidiobolomycota, Calcarisporiellomycota and Aphelidiomycota account for less than 1%.

[0113] In addition, Olpidiomycota was only detected in the BX sampling site, Basidiobolomycota and Calcarisporiellomycota were only detected in ZMF, and Aphelidiomycota was only detected in BX and HSK.

[0114] 3.1.6 Structural composition of soil bacterial and fungal communities at the genus level

[0115] The top 20 dominant bacterial genera of the samples were analyzed by sequencing. Figure 7As shown, some of the dominant bacterial genera are: Subgroup_2 (11.43% ~ 15.87%), AD3 (5.19% ~ 14.61%), Acidothermus (Acidothermus: 2.68% ~ 5.87%). These three genera are the dominant bacterial genera in the ancient tree tea garden. KF-JG30-C25, JG30-KF-AS9, Bryobacter, Candidatus_Solibacter, Acidibacter, Bradyrhizobium, WPS-2, Mycobacterium, HSB_OF53-F07, IMCC26256, Subgroup_13, Pajaroellobacter, Burkholderia-Caballeronia-Paraburkholderia, Roseiarcus, Haliangium, Gemmatimonas, and TK10.

[0116] The results of the dominant bacterial genera in the ancient tea garden are similar to those of previous studies. The dominant genera of tea garden soil bacterial communities are mainly Subgroup_2, AD3, Acidothermus, Acidibacter, Rhizomicrobium and Bradyrhizobium (Li Huilin et al., 2017; Wang Feng et al., 2022; Zhang Yi et al., 2023). Acidothermus is the dominant microbial species in tea gardens and is significantly correlated with physical and chemical indicators in tea garden soil (total organic carbon, total phosphorus and available phosphorus content) (Fu et al., 2021).

[0117] The top 20 dominant fungal genera of the samples were analyzed by sequencing. Figure 8As shown in the figure, the main dominant fungal genera are Saitozyma (17.47% to 55.66%) and Mortierella (4.32% to 12.01%), which are the dominant fungal genera in ancient tea gardens. In addition, the abundance of Apiotrichum in BX ancient tea garden is significantly higher than that in other ancient tea gardens. Fusarium, Anguillospora, Haglerozyma, Gamsia, Archaeorhizomyces, Paraboeremia, Mycosphaerella, Thozetella, llyonectria, Periconia, Psathyrella, Phialocephala, Pestalotiopsis, Helicoma, Pyrenochaetopsis, Trichoderma and Lecanicillium.

[0118] 3.2 Analysis of physical and chemical properties of soil in single-bush ancient tea garden

[0119] Combined with Tables 5 and 6, the physical and chemical indicators and fertility index of the surface soil of the ancient tree tea gardens show that most of the indicators of the planting soil of the four ancient tree tea gardens in Fenghuang Mountain have reached or are close to the Class I fertility level for tea tree planting. Only the available potassium of the surface planting soil of the BX tea garden is at the Class II fertility level, while the available potassium of the surface planting soil of the other tea gardens is at the Class III fertility level. There are no significant differences in the three indicators of pH, AN and AP among the four tea gardens. The AK content is significantly higher in HSK than in ZMF and BX, but not significantly different from DAF; the SOM content is significantly higher in BX than in ZMF, but not significantly different from BX and DAF; the alkaline nitrogen content is significantly higher in HSK, BX and DAF than in ZMF; the available phosphorus content is significantly higher in DAF than in BX and HSK, but not significantly different from ZMF; the available potassium content is significantly higher in BX than in the other three tea gardens.

[0120] Combined with Tables 7 and 8, the physical and chemical indicators and fertility index of the subsurface soil of the ancient tea garden show that most of the indicators of the planting soil in several tea gardens in Fenghuang Mountain have reached or are close to the Class I fertility level for tea tree planting. In this study, the available potassium of the subsurface planting soil of the ancient tea garden was at the Class III fertility level. From the data, there was no significant difference in the four indicators of pH value, total nitrogen, total phosphorus and available potassium among the four tea gardens. The total potassium content showed that HSK was significantly higher than ZMF and BX, but not significantly different from DAF; the organic matter content showed that BX and HSK were significantly higher than ZMF and DAF; the alkaline nitrogen content showed that HSK, BX and DAF were significantly higher than ZMF; the available phosphorus content showed that DAF was significantly higher than HSK, but not significantly different from BX and ZMF. The available potassium level of the tea garden soil at several sampling points did not reach the Class I fertility level for tea tree planting. Judging from the data, the DAF tea garden has the highest soil grade, while the ZMF tea garden has the lowest soil grade. The fertility differences mainly lie in alkaline nitrogen and available phosphorus.

[0121] Table 5 Physical and chemical indexes of surface soil in single-bush ancient tea garden

[0122]

[0123] Note: Different lowercase letters in the same column indicate significant differences at the P<0.05 level (n=3).

[0124] Table 6 Surface soil fertility index of single-bush ancient tree tea garden

[0125]

[0126]

[0127] Table 7 Physical and chemical indexes of subsurface soil in single-bush ancient tea garden

[0128]

[0129] Note: Different lowercase letters in the same column indicate significant differences at the P<0.05 level (n=3).

[0130] Table 8 Subsurface soil fertility index of single-bush ancient tree tea garden

[0131]

[0132] 3.3 Analysis of soil elements in single-bush ancient tea garden

[0133] 3.3.1 Distribution characteristics of soil elements in single-bush ancient tea gardens

[0134] Table 9 Metal element contents in the surface soil of the single-bush ancient tree tea garden (mg / kg)

[0135]

[0136] Table 10 Contents of metal elements in the subsurface soil of different single-bush ancient tree tea gardens (mg / kg)

[0137]

[0138]

[0139]

[0140]

[0141] The soil element distribution characteristics of the single-bush ancient tea garden studied in this paper are shown in Tables 9, 10, 11 and Fig.11 As shown in the figure, the average soil background value in Guangdong Province refers to the background value of soil elements in China (China Environmental Monitoring Center, 1990). It can be seen that the contents of B, Zr, Hf, As, and Ni in the surface soil of the single-bush ancient tea garden are lower than the average soil background value in Guangdong Province, and the contents of other metal elements are higher than the average soil background value in Guangdong Province. The coefficient of variation of each metal element ranges from 11.60% to 259.67%. It is generally believed that CV < 10% is weak variation, 10% to 100% is medium-intensity variation, and CV ≥ 100% is strong variation (Zhong Xiaolan et al., 2007; Sidikjan et al., 2022). The coefficient of variation of the surface soil belongs to medium-strong variation. The contents of B, Sr, Co, Zr, Hf, and Ni in the sub-surface soil are lower than the average soil background value in Guangdong Province, and the contents of other metal elements are higher than the average soil background value in Guangdong Province. The coefficient of variation of each metal element ranges from 14.54% to 255.95%, which belongs to medium-strong variation. The coefficient of variation of the surface and subsurface soils showed that the spatial distribution of the metal element content in the soil of the single-bush ancient tree tea garden was relatively discrete.

[0142] Specifically, in each single-bush ancient tree tea garden, the content of Mn, Ba, Ti, Zr, V, and Cr in the surface soil of the ZMF tea garden is lower than the soil background value of Guangdong Province; the content of Mn, B, Ba, Ti, Zr, V, and Cr in the sub-surface soil is lower than the soil background value of Guangdong Province, and the content of other metal elements is higher than the average value of the soil background of Guangdong Province. The content of B, Li, Cu, Zr, Hf, and Ni in the surface soil of the BX tea garden is lower than the soil background value of Guangdong Province; the content of B, Co, Zr, Hf, and Ni in the sub-surface soil is lower than the soil background value of Guangdong Province, and the content of other metal elements is higher than the average value of the soil background of Guangdong Province. The content of B, Zr, and Hf in the surface soil of the HSK tea garden is lower than the soil background value of Guangdong Province, the content of B, Li, Co, Zr, and Ni in the sub-surface soil is lower than the soil background value of Guangdong Province, and the content of other metal elements is higher than the average value of the soil background of Guangdong Province. The contents of B, Zr, Hf, and Ni in the surface soil of DAF tea garden were lower than the soil background values ​​in Guangdong Province, and the contents of B, Li, and Zr in the subsurface soil were lower than the soil background values ​​in Guangdong Province. The contents of other metal elements were higher than the average soil background values ​​in Guangdong Province.

[0143] Compared with the surface soil, the contents of Al, Mg, Fe, Zn, Ba, Cu, Bi, Mo, Ti, Cr and As in the subsurface soil are higher than those in the surface soil, indicating a trend of metal elements with strong surface activity leaching from the surface downward under humid climatic conditions. There is no obvious difference in the contents of most other metal elements between the surface and subsurface soils.

[0144] 3.3.2 Soil metal element quality assessment

[0145] 3.3.2.1 Geoaccumulation Index Method

[0146] The evaluation criteria for geoaccumulation index are shown in Table 12.

[0147] from Fig.12 , 14 It can be seen that the average geoaccumulation index of B, Ba, Li, Zr, Hf, Cr, As, and Ni in the surface soil of the single-bush ancient tea garden is less than 0, indicating that the metal elements in the surface soil of these tea gardens are basically at a non-polluted level, the Ca, Na, Zn, and Sn elements in the surface soil are at a moderate pollution level, the Mg, Fe, Al, Mn, Cu, Sr, Co, Ti, and V elements in the surface soil are at a light-moderate pollution level, the Mo element in the surface soil and sub-surface soil is at a strong-extremely serious pollution level, and the geoaccumulation index of Bi in the surface soil and sub-surface soil is greater than 5, which is at an extremely serious pollution level. In general, the geoaccumulation index of metal elements in the sub-surface soil is higher than that in the surface soil, indicating that these metal elements are greatly enriched in the sub-surface soil.

[0148] Table 12 Evaluation criteria for geoaccumulation index

[0149]

[0150]

[0151] 3.3.2.2 Enrichment factor method

[0152] The size of the factor divides the degree of metal element contamination into five levels, see Table 13.

[0153] Table 13 Enrichment factor classification table

[0154]

[0155] from Fig.14 , 16 It can be seen that in the surface soil, the mean enrichment factors of Ca, Mn, and Na in the single-bush ancient tree tea garden are between 2 and 4, reaching the medium pollution level, and the mean enrichment factors of the other metal elements are all less than 2, belonging to no pollution to slight pollution, Mo element reaches the heavy pollution level, Bi element reaches the serious pollution level, which is greatly affected by human activities and needs more attention. In the sub-surface soil, the mean enrichment factors of Ca, Mn, Na, Cu, and As in the single-bush ancient tree tea garden are between 2 and 4, reaching the medium pollution level, and the mean enrichment factors of the other metal elements are all less than 2, belonging to no pollution to slight pollution, Mo element reaches the heavy pollution level, Bi element reaches the extremely serious pollution level, which is greatly affected by human activities and needs more attention.

[0156] 3.3.2.3 Nemerow Comprehensive Pollution Index

[0157] like Fig.16 , 17 As shown in the figure, in the surface soil of the single-bush ancient tea garden, except for the single factor index of B, Ti, Zr, and As, the mean values ​​of the single factor index of the other metals are all greater than 1, and the Bi and Mo elements are 60.80 and 27.39 respectively, which may be seriously polluted. In the sub-surface soil of the single-bush ancient tea garden, except for the single factor index of B, Sr, Co, Zr, Hf, As, and Ni, the mean values ​​of the single factor index of the other metals are all greater than 1, and the Bi and Mo elements are 83.95 and 28.25 respectively, which may be seriously polluted.

[0158] Table 14 Nemerow index method pollution degree classification

[0159]

[0160] like Fig.18 , 19As shown, in the surface soil of the Dancong ancient tea garden, the Nemerow comprehensive pollution index of the Zr element is less than 1, which is within the warning line; the Nemerow comprehensive pollution index of Al, B, Li, Hf, Cr, As, and Ni elements is less than 2, which is a light pollution level; the Nemerow comprehensive pollution index of the remaining elements is greater than 3, which is a heavy pollution level. Among them, the Bi and Mo elements are 108.41 and 30.17 respectively, which may be seriously polluted. In the sub-surface soil of the Dancong ancient tea garden, the Nemerow comprehensive pollution index of the B and Zr elements is less than 0.7, the Nemerow comprehensive pollution index of the Al, B, Li, Hf, Cr, and Ni elements is less than 2, which is a light pollution level; the Nemerow comprehensive pollution index of the Co element is less than 3, which is a moderate pollution level; the Nemerow comprehensive pollution index of the remaining elements is greater than 3, which is a heavy pollution level. The Bi and Mo elements are 179.05 and 34.79 respectively, which may be seriously polluted.

[0161] 3.3.2.4 Potential ecological hazard index method

[0162] Table 15 Potential ecological risk assessment index classification standards

[0163]

[0164]

[0166]

[0167] Table 17 Statistical results of potential ecological risk index of metal elements in surface soil

[0168]

[0169] The potential ecological risk assessment results are shown in Tables 16, 17 and Fig. 20 , 21The order of Eri of metal elements in the surface soil is Cu(11.18)>Co(7.50)>V(5.44)>Zn(4.34)>As(3.46)>Ni(3.24)>Mn(3.14)>Cr(2.80). The Eri values ​​of the eight metal elements are all less than 40, indicating mild ecological hazards. The comprehensive potential ecological risk index RI ranges from 16.15 to 63.65, which is at a low potential ecological risk. In the surface soil, the Cu element has the highest contribution rate to the potential ecological risk of the surface soil, accounting for 27.19%, followed by Co and V elements, accounting for 18.25% and 13.23% respectively, and the contribution rates of the remaining metal elements are less than 10%. The order of Eri of the nine metal elements in the subsurface soil is As (43.16) > Cu (17.35) > Zn (5.38) > V (5.26) > Co (4.05) > Mn (3.11) > Ni (3.07) > Cr (2.91). Except for the As element with an Eri value of 43.16, the Eri values ​​of the other seven metal elements are all less than 40, showing a mild ecological hazard. The comprehensive potential ecological risk index RI ranges from 61.90 to 102.02, which is at a low potential ecological risk. The As element has the highest contribution rate to the potential ecological risk of the surface soil, accounting for 51.20%, followed by the Cu element, accounting for 20.58%, and the contribution rates of the remaining metal elements are less than 10%.

[0170] In general, the four soil quality evaluation methods have similar conclusions. Most of the soil samples in the Phoenix Ancient Tree Tea Garden are at a level of no pollution to slight pollution. It is worth noting the content of Mo and Bi in the soil. The main reason is that most of the tea gardens sampled are located on high-altitude mountains, there are no large chemical companies nearby, there are fewer traffic arteries, and there are fewer human activities, so the soil is less polluted.

[0171] 3.4 Analysis of substances contained in fresh tea leaves

[0172] Analysis results of tea leaf content indicators among four ancient tea gardens ( Fig. 22 , Table 18) shows that there is no significant difference between GA, EGC, C, EC, GCG, ECG, catechins and theanine. Among the indicators of catechin components, EGCG has the highest content, followed by EGC and ECG, then EC, GCG and C, and GC and GA have the lowest content. In terms of the total amount of catechins, DAF has the highest content and ZMF has the lowest content. In terms of the total amount of theanine, ZMF has the highest content and DAF has the lowest content. In terms of the total amount of caffeine, ZMF has the highest content and DAF has the lowest content, and the content of caffeine in ZMF is significantly higher than that in DAF.

[0173] The astringency of tea mainly comes from catechins in polyphenols, especially ester catechins. Therefore, the ratio of four ester catechins to the total catechin content is used to evaluate the astringency of tea, which is defined as the astringency index. The astringency index of tea is mainly contributed by epigallocatechin gallate (EGCG) and epicatechin gallate (ECG), while catechin gallate (GA) and gallocatechin gallate (GCG) have no effect on the astringency index (Table 19). Although the total amount of catechins varies between different sampling points, the astringency index does not show any difference in catechins between different sampling points. This shows that the astringency index of fresh tea leaves cannot be used to compare the differences in catechins at different sampling points. During the processing, catechins will undergo chemical reactions, such as decomposition and transformation. In terms of the total amount of catechins, DAF has the highest content and ZMF has the lowest content. This shows that DAF fresh leaves are more resistant to processing and have greater potential for quality maintenance and improvement after processing.

[0174] Table 18 Comparative analysis of the content of substances in fresh leaves of different ancient tea gardens (%)

[0175]

[0176] Note: Different small letters indicate significant differences at the P<0.05 level (n=3).

[0177] Table 19 Astringency index of fresh tea leaves

[0178]

[0179] 3.5 GC-MS component analysis of volatile substances in fresh tea leaves

[0180] After headspace solid phase microextraction, fresh tea leaves were separated and identified by gas chromatography-mass spectrometry. Generally speaking, saturated alkane compounds have almost no aroma (Lü Shidong et al., 2014). Therefore, when analyzing aroma components, volatile compounds such as saturated alkanes are removed before analyzing aroma components. After removing the impurities of volatile components, a total of 39 volatile components were identified in the fresh tea leaves of the four ancient tea gardens. The types of volatiles were roughly the same, but the contents were different. ZMF detected 26 volatile compounds, BX detected 33 volatile compounds, HSK detected 30 volatile compounds, and DAF detected 29 volatile compounds.

[0181] Among the volatile components of fresh leaves (Table 20), ZMF has 8 alcohols, 5 esters and 5 olefins; BX has 7 alcohols, 7 esters and 9 olefins; HSK has 6 alcohols, 8 esters and 7 olefins; DAF has 7 alcohols, 7 esters and 5 olefins. Overall, the total volatiles of ZMF are 2866.65 ng / g, the total volatiles of BX are 2428.67 ng / g, the total volatiles of HSK are 1995.48 ng / g, and the total volatiles of DAF are 1623.20 ng / g. Among them, the total volatiles of ZMF are the highest, the total volatiles of DAF are the lowest, and the total volatiles of ZMF are significantly higher than those of DAF. The volatile components with higher content in fresh leaves are alcohols and esters, followed by aldehydes and olefins, while the content of ketones and phenols is extremely low.

[0182] Table 20 Number of types of volatile components in fresh tea leaves from different ancient tea gardens

[0183]

[0184] 3.5.1 PCA analysis of volatile components in fresh tea leaves

[0185] PCA analysis was performed on the 39 volatile components in the fresh leaves to obtain the principal components and their corresponding eigenvalues, variance contributions and cumulative contributions (Table 21). The variance contribution of PC1 reached 95.89%, the variance contribution of PC2 reached 1.74%, and the cumulative variance contribution of these two principal components was 97.63%. Therefore, the information of the volatile component variables of the fresh leaves of the single-bush ancient tea tree can basically be explained by PC1 and PC2.

[0186] 21 Eigenvalues ​​and variance contribution rates of the principal components of fresh leaves

[0187]

[0188] Table 22 Loading matrix corresponding to the first two principal components

[0189]

[0190]

[0191] By principal component analysis of the samples, the scores of the four tea garden fresh leaf samples on PC1 were basically the same, ZMF was positively correlated with PC2, and DAF, BX and HSK were negatively correlated with PC2. After analyzing the 39 aroma substance variables, the distribution of the score was relatively compact, indicating that the variables responded to the system more consistently. The loading matrix corresponding to the key outliers on PC1 and PC2 is shown in Table 22. The seven volatile substances, linalool acetate, geraniol, methyl salicylate, linalool oxide II, linalool oxide I, decanal and 2,4-di-tert-butylphenol, were negatively correlated on PC2, while linalool and trans-2-hexenal were positively correlated.

[0192] By visualizing the sample scores and component loadings, we can obtain the principal component analysis biplot of fresh leaf volatile components ( Fig.23 ), the serial numbers of the points in the figure correspond to the table. The angles of ZMF, BX, HSK and DAF in the biplot are less than 90 degrees, indicating that there is a positive correlation between the samples. ZMF is located in the second quadrant, and is highly positively correlated with linalool and trans-2-hexenal. Therefore, these two volatile substances can represent the characteristic information of ZMF fresh tea leaves to a certain extent. DAF, HSK and BX are all located in the third quadrant. DAF, HSK and BX are highly positively correlated with linalool acetate, geraniol, methyl salicylate, linalool oxide II, linalool oxide I, decanal and 2,4-di-tert-butylphenol. Therefore, these volatile substances can represent the characteristic information of DAF, HSK and BX fresh tea leaves to a certain extent.

[0193] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for regulating the quality of tea leaves from single-bush ancient trees, characterized in that: The method includes any of the following: Regulate soil diversity in single-bush ancient tea gardens; Enriching soil elements in single-bush ancient tea gardens; Improve soil fertility in single-bush ancient tea gardens; Improve the secondary metabolites of tea leaves in single-bush ancient tea gardens; Adjust the contents of fresh tea leaves by adjusting the soil elements; The content and volatile substances in the fresh tea leaves are adjusted by adjusting the elements in the fresh tea leaves.

2. The method for controlling the quality of tea leaves from ancient single bush trees according to claim 1, characterized in that: The steps of regulating soil diversity in the single-bush ancient tree tea garden include: The soil bacterial diversity was improved by adjusting the pH value, total nitrogen, alkaline-hydrolyzed nitrogen and total potassium in the soil of the single-bush ancient tree tea garden. Among them, the pH value, total nitrogen content, alkaline-hydrolyzed nitrogen content and total potassium content in the soil of the single-bush ancient tree tea garden were positively correlated with the soil bacterial diversity.

3. The method for adjusting soil diversity in a single-bush ancient tea garden according to claim 2, characterized in that: The bacterial diversity of the single-bush ancient tree tea garden includes: The top three bacterial phyla in the rhizosphere soil of the single-bush ancient tea garden were Proteobacteria, Acidobacteria, Chloroflexi, and Actinobacteria. The top three fungal phyla in the rhizosphere soil of the single-bush ancient tea garden were Basidiomycota, Ascomycota and Mortierella. The dominant bacterial genera in the soil of the single-bush ancient tea garden were Subgroup_2, AD3, Thermoacidobacterium, Acidobacterium, Rhizobium, and Bradyrhizobium; The dominant bacterial genera in the rhizosphere soil of the single-bush ancient tree tea garden are Salamander, Mortierella and Fusarium.

4. The method for controlling the quality of tea leaves from ancient single bush trees according to claim 1, characterized in that: The steps of enriching the soil elements of the single-bush ancient tree tea garden include: Enrich the soil with Ca, Mg, Fe, Al, Mn, Ba, Co, Mo and Ti elements by increasing the level of alkaline nitrogen and organic matter in the soil.

5. The method for controlling the quality of tea leaves from ancient single bush trees according to claim 1, characterized in that: The steps of improving soil fertility in the single-bush ancient tree tea garden include: When the soil fertility of a single-bush ancient tree tea garden is lower than level I, the soil fertility can be improved by applying potassium fertilizer.

6. The method for controlling the quality of tea leaves from ancient single bush trees according to claim 1, characterized in that: The step of increasing the secondary metabolites of tea leaves in the single-bush ancient tea garden comprises: By increasing the pH value of the soil in the single-bush ancient tea garden, the catechin content of tea leaves can be increased. The content of theanine in tea leaves can be increased by increasing the available potassium in the soil of single-bush ancient tea gardens.

7. The method for controlling the quality of tea leaves from ancient single bush trees according to claim 1, characterized in that: The step of regulating the contents of fresh tea leaves comprises: The caffeine content in tea leaves was controlled by adjusting the alkaline nitrogen level, total nitrogen level and organic matter level in the soil. Among them, the alkaline nitrogen level, total nitrogen level and organic matter level in the soil were negatively correlated with the caffeine content. The substances contained in fresh tea leaves are controlled by adjusting the elements Mg, V, Ta, Sn, Li, Zr, Mn, Ti and Cr in the soil. Among them, Mg, V, Ta, Sn, Li and Zr are positively correlated with the substances contained in fresh tea leaves, while Mn, Ti and Cr are negatively correlated with the substances contained in fresh tea leaves.

8. The method for controlling the quality of tea leaves from ancient single bush trees according to claim 7, characterized in that: The top seven volatile substances in the fresh tea leaves are linalool, linalool acetate, trans-2-hexenal, geraniol, methyl salicylate, linalool oxide I and linalool oxide II.

9. The method for controlling the quality of tea leaves from ancient single bush trees according to claim 8, characterized in that: The tea leaves of the single-bush ancient tea garden utilize geraniol, trans-2-hexenal and methyl salicylate substances to resist insects.

10. The method for controlling the quality of tea leaves from ancient single bush trees according to claim 1, characterized in that: The step of adjusting the types of substances and volatile substances contained in the fresh tea leaves by adjusting the elements of the fresh tea leaves comprises: By increasing the content of N, P, Mg, Zn, Ca, Sn and Ni in fresh tea leaves, The aroma components of fresh tea leaves can be improved by increasing the Sr, Al, K, Si, V, Ni and Zr elements in fresh tea leaves.

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