Tea quality improvement and detection method based on trichoderma yunnanense

Abstract

The invention discloses a tea quality improving method based on trichoderma yunnanense. The tea quality improving method comprises the following steps that a trichoderma yunnanense solid fungicide is adopted to conduct leaf spraying on a tea tree, and the trichoderma yunnanense solid fungicide is adopted to conduct root irrigation on the tea tree. By means of the method, the yield of tea trees can be increased, and the content of selenium, tea polyphenol, caffeine, catechin and the like in produced tea leaves is obviously increased. Agronomic characters such as the germination rate, the hundred-bud weight and the yield of the tea trees are measured, and quality indexes such as selenium content, water extract, tea polyphenol and amino acid are analyzed. The Trichoderma yunnanense powder root irrigation and leaf spraying treatment effect is optimal, the yield is increased by 50.60% compared with that of a blank control, and the average yield reaches 55.45 kg / 667 m < 2 >; the total selenium content (4.83 mg / kg) and the organic selenium content (4.80 mg / kg) are the highest; according to the present invention, the content of the water extract (49.46%), the content of the tea polyphenol (12.70%), the content of the caffeine (3.41%) and the total content of the catechin (23.91%) are significantly increased, the content of the flavor amino acids such as alanine, glycine and the like is the highest, and the phenol-ammonia ratio (67.09%) is lower than the control group.

Description

Technical Field

[0001] This invention relates to methods for cultivating and testing tea, and particularly to methods for improving and testing tea quality based on Trichoderma yunnanensis. Background Technology

[0002] As one of the world's most consumed non-alcoholic beverages, tea's quality and safety have always been a research hotspot in agricultural science. With increasing consumer health awareness, the market demand for functional tea products such as selenium-enriched tea and tea with high antioxidant activity continues to grow, driving the transformation of tea cultivation techniques towards green and functional approaches. However, current tea garden production commonly suffers from problems such as soil acidification due to excessive use of chemical fertilizers, imbalances in beneficial microbial communities, and declining tea quality, necessitating the development of environmentally friendly tea cultivation and regulation technologies. Summary of the Invention

[0003] The purpose of this invention is to provide a method for improving and detecting tea quality based on Trichoderma Yunnanense, which can increase the yield of tea trees and significantly increase the content of selenium, tea polyphenols, caffeine, catechins and other substances in the produced tea.

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0005] Methods for improving tea quality based on *Trichoderma yunnanensis* include the following: foliar spraying of tea trees with *Trichoderma yunnanensis* solid inoculant and root irrigation of tea trees with *Trichoderma yunnanensis* solid inoculant. *Trichoderma yunnanensis* solid inoculant refers to a nutrient solution made by diluting *Trichoderma yunnanensis* solid mycelium with water.

[0006] In the aforementioned method for improving tea quality based on Trichoderma Yunnanense, the root irrigation method is as follows:

[0007] Yunnan Trichoderma solid mycelium is added to water to make a solvent, which is then introduced into a root irrigation device. The root irrigation device includes a sealed bucket, a screw cap, and a sealing cap. The top of the sealed bucket has a threaded opening, and the screw cap is threaded onto the threaded opening. The sealing cap is fitted around the screw cap and has several air vents arranged in an arc. The sealing cap has a semi-circular plate, which can be covered by the semi-circular plate by rotating the sealing cap. A conduit is connected to the bottom of the sealed bucket. One end of the conduit is connected to the sealed bucket, and the other end is located around the roots of the underground tea tree. By rotating the sealing cap, the number of air vents covered by the semi-circular plate can be adjusted, thereby adjusting the speed at which the solvent in the sealed bucket flows to the roots of the tea tree through the conduit.

[0008] The tea quality detection method based on Trichoderma Yunnanense includes the following: tea sample collection and yield determination; tea selenium content determination; tea chemical composition determination; and tea amino acid content determination.

[0009] In the aforementioned tea quality detection method based on *Trichoderma yunnanensis*, the specific methods for tea sample collection and yield determination are as follows: Fresh tea leaves with one bud and two leaves are collected from the tea tree in spring, using a 1m... 2 Sampling was performed using a sampling rack; the fresh weight was measured immediately after harvesting and then converted into yield; the weight of 100 tea buds and the bud density were measured during harvesting; the samples were rapidly frozen in liquid nitrogen and stored in an ultra-low temperature freezer at -80℃; all leaves were randomly sampled, with 10 biological replicates per group.

[0010] In the aforementioned tea quality detection method based on Trichoderma Yunnanense, the selenium content of tea is determined using the following method: atomic fluorescence spectrometry in the national standard GB5009.93-2017 is used to detect the selenium, inorganic selenium, and organic selenium content in tea.

[0011] In the aforementioned method for detecting tea quality based on *Trichoderma yunnanensis*, the determination of the chemical components of tea is specifically carried out using the following methods: Water extract: The water extract of tea is determined using the national standard method GB / T 8305-2013; Tea polyphenols, gallic acid, gallocatechin, gallocatechin gallate, epigallocatechin, catechin, epicatechin, epigallocatechin gallate, and epicatechin gallate: These are detected using the national standard method GB / T 8313-2018, the method for detecting the content of tea polyphenols and catechins in tea; The total catechin content is calculated based on the above detection data.

[0012] In the aforementioned method for detecting tea quality based on *Trichoderma yunnanensis*, the determination of the amino acid content in tea specifically adopts the following method: Total free amino acids: The total free amino acids in tea are detected using the azithrone colorimetric method according to national standard GB 5009.124-2016; The free amino acid content is determined using the amino acid analyzer method in national standard GB / T 30987-2020 to determine the free amino acid components and content in tea.

[0013] Compared with existing technologies, this invention can increase the yield of tea trees, and the content of selenium, tea polyphenols, caffeine, catechins, etc. in the produced tea leaves is significantly increased. Agronomic traits such as budding rate, weight of 100 buds, and yield of tea trees were measured, and quality indicators such as selenium content, water extract, tea polyphenols, and amino acids were analyzed. [Results] The root irrigation + foliar spray treatment with *Trichoderma yunnanense* powder showed the best effect: yield increased by 50.60% compared with the blank control, with an average yield of 55.45 kg / 667㎡; the total selenium content (4.83 mg / kg) and organic selenium content (4.80 mg / kg) were the highest; the water extract (49.46%), tea polyphenols (12.70%), caffeine (3.41%), and total catechins (23.91%) were significantly increased; the content of flavor amino acids such as alanine and glycine was the highest; and the phenol-to-amino acid ratio (67.09%) was lower than the control. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of one embodiment of a root irrigation device;

[0015] Figure 2 This is a schematic diagram of one embodiment of the screw cap;

[0016] Figure 3 This is a structural schematic diagram of one embodiment of the sealing cap.

[0017] Attached reference numerals: 1-Sealing cap, 2-Screw cap, 3-Threaded opening, 4-Sealing barrel, 5-Conduit, 6-Ventilation hole, 7-Semi-circular plate.

[0018] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Detailed Implementation

[0019] Trichoderma is a type of biocontrol fungus widely found in soil, possessing multiple biological functions such as promoting plant growth, improving nutrient absorption efficiency, and enhancing stress resistance, making it of significant application value in sustainable agricultural development. In recent years, the application of Trichoderma agents on crops such as rice and vegetables has achieved remarkable results, but systematic research on tea trees is relatively scarce, especially regarding its application effects in high-altitude tea garden ecosystems in Southwest China, which remain unclear.

[0020] Guizhou Province is an important high-quality green tea producing area in my country. Its unique karst landforms and climate endow its tea with distinctive flavor and quality, giving it a natural advantage in developing high-quality ecological tea. However, tea gardens generally suffer from unstable yields, insufficient accumulation of characteristic elements such as selenium, and limited quality control technologies, which hinder the high-quality development of the tea industry. Therefore, selecting suitable application methods of Trichoderma fungicides based on local ecological characteristics and exploring their regulatory effects on tea tree growth and quality is of significant theoretical and practical importance for enhancing the competitiveness of Guizhou's tea industry.

[0021] This patent uses a solid *Trichoderma* agent developed in the laboratory as the test material. Different application treatments, including root drenching and root drenching combined with foliar spraying, were set up in mature tea gardens in Anshun, Guizhou Province. Agronomic traits such as budding rate, weight of 100 buds, and yield were systematically measured. Quality indicators such as selenium content, water extract, tea polyphenols, and amino acids were analyzed. By comparing the changes in the main chemical components of tea under different treatments, a scientific basis for optimizing tea cultivation techniques is provided, aiming to achieve a synergistic improvement in the ecological and economic benefits of the tea industry. Therefore, this patent proposes a method for improving tea quality based on *Trichoderma*, which includes the following: 1. Foliar spraying of tea trees with a solid *Trichoderma* agent; 2. Root drenching of tea trees with a solid *Trichoderma* agent. The root irrigation is performed using the following method: Yunnan Trichoderma solid mycelium is added to water to make a solvent, and the solvent is introduced into the root irrigation device; the root irrigation device includes a sealed bucket 4, a screw cap 2, and a sealing cover 1. The top of the sealed bucket 4 has a threaded opening 3, and the screw cap 2 is threaded at the threaded opening 3; the sealing cover 1 is fitted around the screw cap 2, and the screw cap 2 has several air holes 6 arranged in an arc. The sealing cover 1 has a semi-circular plate 7, and the semi-circular plate 7 can cover the air holes 6 by rotating the sealing cover 1 on the screw cap 2; the bottom of the sealed bucket 4 is connected to a conduit 5, one end of the conduit 5 is connected to the sealed bucket 4, and the other end of the conduit 5 is located around the underground tea tree roots; by rotating the sealing cover 1, the number of air holes 6 covered by the semi-circular plate 7 is adjusted, thereby adjusting the speed at which the solvent in the sealed bucket 4 flows to the tea tree roots through the conduit 5.

[0022] When all the ventilation holes 6 are covered, meaning they cannot allow air to pass through, air cannot enter the sealed container 4, and therefore the nutrient solution inside the sealed container 4 cannot flow to the roots of the tea plant through the conduit 9. By gradually opening the ventilation holes 6, air can enter the sealed container 4 at a gradually faster rate, and the nutrient solution inside the sealed container 4 can flow to the roots of the tea plant at a gradually faster rate. Thus, adjustable-speed root irrigation is achieved through a very simple structure.

[0023] To verify the effectiveness of the above methods, five methods were used simultaneously for comparison.

[0024] Method 1: Untreated tea leaves serve as a blank control;

[0025] Method 2: 5% polyoxin (foliar spray);

[0026] Method 3: Granular fertilizer application;

[0027] Method 4: Drenching roots with Trichoderma Yunnanense powder;

[0028] Method 5: Apply Yunnan Trichoderma powder for root irrigation and foliar spraying.

[0029] The experiment was conducted in November 2024. All fertilizers were applied to each plot on the same day. Except for the fertilization method, the tea garden management was the same as the conventional tea garden management method.

[0030] Polyoxin (Guiyang Hongshuo Biological Reagent Co., Ltd.); granular microbial fertilizer (Guizhou Yibaiyi Biotechnology Co., Ltd.); Yunnan Trichoderma solid inoculant (Guizhou Yibaiyi Biotechnology Co., Ltd.); the tea variety was Fuding Dabai. A small-plot experiment was conducted in an established tea garden of Anshun Waterfall Tea Industry Co., Ltd. in Chaling Village, Jiuzhou Town, Xixiu District, Anshun City, Guizhou Province. Chaling Village has an average altitude of 1356m, an average annual temperature of 14.3℃, an annual rainfall of 1360mm, and yellow loam soil with a pH of around 5.5.

[0031] Tea sample collection and yield determination: Fresh tea leaves with one bud and two leaves were collected from tea trees in spring (April 2025). Samples were collected using a 1m... 2 Sampling was performed using a sampling rack. Fresh weight was obtained immediately after harvest and then converted into yield (kg / 667㎡). The weight of 100 tea buds and bud density were measured during harvest. Samples were rapidly frozen in liquid nitrogen and stored in an ultra-low temperature freezer at -80℃. All leaves were randomly sampled, with 10 biological replicates per group.

[0032] Selenium content determination in tea: The content of selenium, inorganic selenium and organic selenium in tea was determined by atomic fluorescence spectrometry according to the national standard method (GB 5009.93-2017).

[0033] Determination of Chemical Composition of Tea: Water Extract: The water extract of tea was determined according to the national standard method GB / T 8305-2013 "Determination of Water Extract of Tea". Tea Polyphenols, Gallic Acid, Gallocatechin (GC), Gallocatechin Gallate, Epigallocatechin (EGC), Catechins, Epicatechin (EC), Epigallocatechin Gallate, and Epicatechin Gallate: These were determined according to the national standard method GB / T 8313-2018 "Detection Method for the Content of Tea Polyphenols and Catechins in Tea". The total catechin content was calculated based on the above test data. Caffeine: The caffeine content was determined according to the national standard GB / T 8312-2013 "Determination of Caffeine in Tea".

[0034] Determination of amino acid content in tea: Total free amino acids: The total free amino acids in tea were determined using the national standard method (GB 5009.124-2016) trichomoniasis colorimetric method.

[0035] The free amino acid content was determined using the amino acid analyzer method in the national standard method (GB / T 30987-2020) to determine the free amino acid components and content in tea.

[0036] Results and Analysis

[0037] Effects of different microbial agents on tea yield: As shown in Table 1, compared with the blank control, the budding rate, weight of 100 buds, weight of buds per square meter, and average yield per mu of tea trees treated with different microbial agents all increased. Budding rate (number of buds per 0.25 square meters): Granular fertilizer > Yunnan Trichoderma powder root drenching > Yunnan Trichoderma powder root drenching + foliar spray > 5% polyoxin (foliar spray) > Blank control, respectively 140.67, 130.00, 129.67, 108.00, 86.86. Weight of 100 buds: Yunnan Trichoderma powder root drenching + foliar spray > 5% polyoxin (foliar spray) > Granular fertilizer > Yunnan Trichoderma powder root drenching > Blank control, respectively 66.70g, 54.80g, 54.37g, 51.63g, 44.27g. The yield per square meter of buds was as follows: Yunnan Trichoderma powder root drenching + foliar spray > Yunnan Trichoderma powder root drenching > granular fertilizer > 5% polyoxin (foliar spray) > blank control, with values ​​of 83.13g, 75.87g, 73.93g, 62.40g, and 55.20g respectively. The average yield per mu (unit of area) was also as follows: Yunnan Trichoderma powder root drenching + foliar spray > Yunnan Trichoderma powder root drenching > granular fertilizer > 5% polyoxin (foliar spray) > blank control. Compared to the blank control, Yunnan Trichoderma powder root drenching + foliar spray increased yield by 50.60%, Yunnan Trichoderma powder root drenching by 37.44%, granular fertilizer by 33.94%, and 5% polyoxin (foliar spray) by 13.04%. This indicates that Yunnan Trichoderma powder root drenching + foliar spray treatment can increase tea yield.

[0038]

[0039] Table 1. Effects of different microbial inoculants on tea yield

[0040] Note: The letter following the numerical value indicates a significant difference (P < 0.05), and the same applies below.

[0041] Effects of different microbial agents on the selenium content of tea: As shown in Table 2, the total selenium content and inorganic selenium content of tea treated with different microbial agents were as follows: Trichoderma fuscum powder root drenching + foliar spray > 5% polyoxin (foliar spray) > Trichoderma fuscum powder root drenching > granular fertilizer > blank control. The total selenium content and inorganic selenium content of tea treated with Trichoderma fuscum powder root drenching + foliar spray were significantly higher than those of tea treated with other microbial agents, at 4.83 mg / kg and 4.80 mg / kg, respectively, representing increases of 156.91% and 156.68% compared to the blank control. This indicates that treating tea trees with Trichoderma fuscum powder root drenching + foliar spray can increase the selenium content of tea leaves.

[0042]

[0043] Table 2. Effects of different microbial agents on selenium content in tea leaves.

[0044] The effects of different microbial treatments on the chemical composition of tea: As shown in Table 3, the tea plants treated with 5% polyoxin (foliar spray), granular fertilizer, Yunnan Trichoderma powder root drenching, and Yunnan Trichoderma powder root drenching + foliar spray all had higher levels of water extract, amino acids, and caffeine than the control group, while the phenol-to-amino acid ratio was lower. However, the tea polyphenol content increased in the Yunnan Trichoderma powder root drenching + foliar spray treatment compared to the control group, while it decreased in the other three treatments. Among them, the Yunnan Trichoderma powder root drenching + foliar spray treatment had the highest levels of tea extract, tea polyphenols, and caffeine, at 49.46%, 12.70%, and 3.41%, respectively; the highest amino acid content was observed in granular fertilizer and Yunnan Trichoderma powder root drenching, at 2.00%. This indicates that the Yunnan Trichoderma powder root drenching + foliar spray method has a more significant effect on improving tea quality.

[0045] Further analysis revealed that treating tea trees with Yunnan Trichoderma powder via root drenching and foliar spraying increased the content of gallic acid catechin, gallocatechin gallate, epigallocatechin (EGC), catechin, epigallocatechin gallate (EGCG), and total catechins, with contents of 0.56%, 0.11%, 3.61%, 10.53%, 6.71%, and 23.91%, respectively (see Table 3). However, the levels of gallic acid, epicatechin (EC), and epicatechin gallate (ECG) in tea trees treated with Yunnan Trichoderma powder via root drenching and foliar spraying were lower than those in the blank control group, suggesting that these three substances may have effects on other aspects of tea tree development (such as disease resistance and yield increase).

[0046]

[0047] Table 3. Effects of different microbial agents on the chemical composition of tea leaves (%)

[0048] The results of free amino acid determination in tea leaves showed that all 18 amino acids were detected in all treatments. The contents of 10 amino acids—alanine, serine, leucine, aspartic acid, arginine, histidine, threonine, glutamic acid, lysine, and tyrosine—were higher in all treatments than in the blank control group; the contents of 4 amino acids—isoleucine, cystine, proline, and methionine—were lower in all treatments than in the blank control group; the glycine content was higher in all treatments except for 5% polyoxin (foliar spray); the valine content was lower in all treatments except for root drenching with *Trichoderma yunnanensis* powder; the tryptophan content was higher in all treatments except for root drenching with *Trichoderma yunnanensis* powder and root drenching with *Trichoderma yunnanensis* powder + foliar spray; and the phenylalanine content was higher in all treatments except for granular fertilizer application (see Table 4).

[0049] Further analysis revealed that the Yunnan Trichoderma powder, used for root drenching and foliar spraying, had the highest contents of alanine, glycine, histidine, threonine, and tyrosine, at 1.16 g / 100g, 1.17 g / 100g, 0.54 g / 100g, 1.03 g / 100g, and 0.82 g / 100g, respectively. Isoleucine, proline, and tryptophan had the lowest contents, at 0.85 g / 100g, 0.70 g / 100g, and 0.18 g / 100g, respectively (see Table 4).

[0050]

[0051] Table 4. Effects of different microbial agents on free amino acids in tea leaves (g / 100g)

[0052] This experiment applied *Trichoderma yunnanense* solid inoculant to tea trees, investigating the effects of different application methods—root drenching and root drenching combined with foliar spraying—on tea yield, selenium content, and quality. The study found that treating tea trees with *Trichoderma yunnanense* solid inoculant via root drenching and foliar spraying increased tea yield, improved selenium content, and enhanced tea quality.

[0053] Selenium is an essential trace element for the human body, possessing antioxidant and immune-boosting functions. The organic selenium in tea is more easily absorbed by the body. The selenium content of tea can be increased through exogenous selenium application, but different types of exogenous selenium and different application methods have a significant impact on the selenium content of tea. The results of this study show that root drenching with *Trichoderma yunnanensis* solid inoculant and root drenching combined with foliar spraying can both increase the selenium content of tea, but root drenching with *Trichoderma yunnanensis* solid inoculant combined with foliar spraying resulted in the greatest increase.

[0054] The content of components such as tea water extract, tea polyphenols, caffeine, and amino acids is closely related to the quality of tea. The content of tea water extract, as an important indicator of the total amount of soluble substances in tea, affects the richness and concentration of the tea soup. Caffeine is a bitter substance in tea; moderate bitterness can enrich the flavor and add body. Moderate intake can stimulate the central nervous system, improve attention, and shorten reaction time, but excessive caffeine intake can have a stimulating effect on people with neurasthenia, potentially leading to insomnia. Long-term sleep deprivation can result in poor mental state and decreased physical performance. Tea polyphenols are natural antioxidants in tea and are a general term for polyphenolic substances and their derivatives in tea. Gallic acid has various biological effects such as antibacterial, anti-inflammatory, and antitumor properties, and is mainly found in aged or fermented tea. After root irrigation and foliar spraying with Yunnan Trichoderma solid inoculant, the content of tea water extract, tea polyphenols, and caffeine was the highest compared to other treatment methods. The suitability of fresh tea leaves for processing is determined by the phenol-to-amino acid ratio. Tea leaves treated with different microbial agents and fertilizers all had phenol-to-amino acid ratios below 7, indicating that they can be used to produce high-quality green tea. After root drenching and foliar spraying with *Trichoderma yunnanensis* solid microbial agent, the amino acid content of the tea leaves increased compared to the control, but the content was not as high as the other three treatments. The gallic acid content of the tea leaves treated with root drenching and foliar spraying with *Trichoderma yunnanensis* solid microbial agent decreased compared to the blank control. Gallic acid may participate in plant defense mechanisms and antioxidant protection during tea tree growth.

[0055] Further analysis of tea polyphenol and amino acid content revealed that tea treated with Yunnan Trichoderma solid-inoculum agent through root drenching and foliar spraying showed increased levels of gallic acid catechin, gallic acid catechin gallate (EGC), epigallocatechin, epigallocatechin gallate (EGCG), and total catechins compared to the control group, with the highest content among the four treatment methods. However, tea treated with Yunnan Trichoderma powder through root drenching and foliar spraying had lower levels of epicatechin (EC) and epicatechin gallate (ECG) than the blank control group, suggesting that these two substances may play other roles in other tea plant processes (such as disease resistance and yield increase). Regarding amino acid content, tea treated with Yunnan Trichoderma solid-inoculum agent through root drenching and foliar spraying showed the highest levels of alanine, glycine, histidine, threonine, and tyrosine, and the lowest levels of isoleucine, proline, and tryptophan. Alanine has a sweet and umami flavor, while glycine is one of the representative sweet amino acids in tea. The combination of alanine and glycine contributes to the sweet and umami flavor of tea, with a mellow aftertaste, giving the tea soup a refreshing sweetness and neutralizing the bitterness of tea polyphenols and the stimulation of caffeine, thus enhancing the "freshness" and palatability of the soup. Histidine has a refreshing taste and works synergistically with umami amino acids such as glutamic acid to enhance the freshness and mellowness of the tea soup. Threonine has a sweet and slightly umami taste, enriching the flavor layers of the tea soup and improving its refreshingness. Tyrosine has a mild bitterness and enhances the flavor concentration. During tea processing, it acts as a precursor, participating in the oxidation and polymerization of polyphenols and the formation of tea pigments and aromatic substances, indirectly affecting the color and aroma of the tea.

[0056] When isoleucine content is moderate, it enhances the purity of tea soup. It works synergistically with other amino acids and tea polyphenols to enrich the flavor profile of tea. However, excessive isoleucine content can disrupt the balanced ratio of amino acids, tea polyphenols, and caffeine in the tea, potentially making the "freshness" of the tea soup bland or even causing a slight sour or fishy taste, thus damaging the harmony of the flavors. Proline is a significant contributor to the sweetness of tea; excessive proline content can make the tea soup overly sweet, masking the freshness and mellowness of the tea itself. This is especially problematic for teas like green tea and oolong tea, which emphasize a "refreshing flavor," as it can lower their quality. Tryptophan possesses certain aroma precursor characteristics, enhancing the aroma complexity of tea. However, during high-temperature roasting, if the tryptophan conversion reaction becomes uncontrolled, it may produce small amounts of indole compounds. If the indole content exceeds the standard, it can cause a pungent off-odor in the tea, severely affecting the aroma quality.

[0057] This study investigated the effects of different application methods of *Trichoderma yunnanensis* solid inoculant on tea tree growth and quality through a small-plot experiment in an established tea garden in Anshun, Guizhou Province. The results showed that the root drenching + foliar spraying treatment with *Trichoderma yunnanensis* powder was the most effective, increasing yield by 50.60% compared to the control, with an average yield of 55.45 kg / mu (approximately 0.067 hectares). This yield increase was mainly achieved by improving germination rate, weight of 100 buds, and weight of buds per square meter. This treatment also showed the highest total selenium content (4.83 mg / kg) and organic selenium content (4.80 mg / kg), providing an effective pathway for selenium enrichment in tea.

[0058] Quality analysis showed that this treatment significantly increased the content of water extract (49.46%), tea polyphenols (12.70%), and caffeine (3.41%), with the total catechin content reaching 23.91%, enhancing the richness and antioxidant activity of the tea infusion. Although the total amino acid content (1.90%) was slightly lower, the content of flavor amino acids such as alanine (1.16g / 100g) and glycine (1.17g / 100g) was the highest, and the phenol-to-amino acid ratio (67.09%) was lower than the control, indicating better suitability for processing fresh leaves into high-quality green tea.

[0059] In summary, the combined application of Yunnan Trichoderma powder through root drenching and foliar spraying can simultaneously improve yield, selenium content, and quality. The mechanism may be related to promoting nutrient absorption and secondary metabolism. It is recommended to promote its application in production to enhance the economic benefits and product competitiveness of tea gardens. Further research could explore its synergistic effects with other biological agents and its long-term impact on soil microecology.

Claims

1. A method for improving tea quality based on Trichoderma Yunnanense, characterized in that, The methods include: foliar spraying of tea trees with Yunnan Trichoderma solid inoculant, and root irrigation of tea trees with Yunnan Trichoderma solid inoculant.

2. The method for improving tea quality based on *Trichoderma yunnanensis* according to claim 1, characterized in that, The root irrigation is performed using the following method: Yunnan Trichoderma solid fungus is added to water to make a solvent, and the solvent is introduced into the root irrigation device; the root irrigation device includes a sealed bucket (4), a screw cap (2) and a sealing cover (1), the top of the sealed bucket (4) has a threaded opening (3), and the screw cap (2) is set at the threaded opening (3) by the thread. The sealing cap (1) is fitted around the screw cap (2). The screw cap (2) has several air holes (6) arranged in an arc shape. The sealing cap (1) has a semi-circular plate (7). By rotating the sealing cap (1) on the screw cap (2), the semi-circular plate (7) can cover the air holes (6). The bottom of the sealed bucket (4) is connected to a conduit (5), one end of the conduit (5) is connected to the sealed bucket (4), and the other end of the conduit (5) is located around the roots of the underground tea tree. By rotating the sealing cap (1), the number of air holes (6) covered by the semi-circular plate (7) can be adjusted, thereby adjusting the speed at which the solvent in the sealed container (4) flows to the roots of the tea tree through the conduit (5).

3. A method for detecting tea quality based on *Trichoderma yunnanensis*, characterized in that, Includes the following: Tea sample collection and yield determination; Determination of selenium content in tea leaves; Determination of chemical components in tea; Determination of amino acid content in tea leaves.

4. The method for detecting tea quality based on *Trichoderma yunnanensis* according to claim 3, characterized in that, The following methods were used for tea sample collection and yield determination: Fresh tea leaves with one bud and two leaves are harvested from the tea tree in spring, using a 1m... 2 Sampling was performed using a sampling rack; the fresh weight was measured immediately after harvesting and then converted into yield; the weight of 100 tea buds and the bud density were measured during harvesting; the samples were rapidly frozen in liquid nitrogen and stored in an ultra-low temperature freezer at -80℃; all leaves were randomly sampled, with 10 biological replicates per group.

5. The method for detecting tea quality based on *Trichoderma yunnanensis* according to claim 3, characterized in that, The following method is used to determine the selenium content in tea: The content of selenium, inorganic selenium, and organic selenium in tea was detected by atomic fluorescence spectrometry, as specified in the national standard GB5009.93-2017.

6. The method for detecting tea quality based on *Trichoderma yunnanensis* according to claim 3, characterized in that, The chemical composition of the tea was determined using the following method: Water extract: The water extract of tea was determined according to the national standard method GB / T 8305-2013. Tea polyphenols, gallic acid, gallocatechin, gallocatechin gallate, epigallocatechin, catechin, epicatechin, epigallocatechin gallate, epicatechin gallate: were detected using the national standard method GB / T8313-2018, "Detection Method for the Content of Tea Polyphenols and Catechins in Tea"; the total catechin content was calculated based on the above test data.

7. The method for detecting tea quality based on *Trichoderma yunnanensis* according to claim 3, characterized in that, The amino acid content of the tea was determined using the following method: Total free amino acids: The total free amino acids in tea were determined using the national standard method GB 5009.124-2016, the azirone colorimetric method. The free amino acid content was determined using the amino acid analyzer method in the national standard GB / T 30987-2020 to determine the free amino acid components and content in tea.

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