Tea tree fluoride content inhibitor, its application and planting method for inhibiting fluoride accumulation in new shoots of tea trees

Abstract

A tea tree fluorine content inhibitor of the present invention and a planting method for inhibiting fluorine accumulation in new shoots of tea trees. By combining different application methods of hydroponics and soil cultivation, the influence of potassium elements at different concentrations in tea tree planting is deeply studied. Specifically, when the added potassium ion content is 435.65 mg / L, it has excellent effects on inhibiting fluorine accumulation in new shoots of tea trees. As an externally applied potassium element, the addition amount in the present invention is much larger than that in the traditional tea tree planting process, effectively improving the resistance of improved tea tree varieties, enhancing the tea tree's resistance to fluorine, reducing fluorine accumulation in new shoots of tea trees, and further improving the safety of tea tree leaves. Compared with other defluorination methods or defluorination additives, it has little impact on the tea garden environment, is green and safe, and is helpful for subsequent tea tree planting, solves the problem of excessive fluorine content in Chinese tea, reduces production costs, improves the product quality and market competitiveness of tea, and has very important significance for promoting the rapid development of the tea industry.

Description

Technical Field

[0001] The present invention relates to the technical field of tea tree planting, and particularly relates to a tea tree fluorine content inhibitor and a planting method for inhibiting the fluorine accumulation in new shoots of tea trees. Background Art

[0002] Fluorine is a major element in the earth's crust, and it exists in soil, water and the atmosphere. High concentrations of fluorine are toxic to organisms. During the production process, it has been found that baker's yeast and brewer's yeast will be killed by a certain concentration of fluoride, and the growth of some pathogens will also be inhibited. If the fluorine concentration in daily drinking water is too high, people will initially show symptoms of "fluorosis" such as drowsiness, fatigue, loss of appetite, dizziness, palpitations, and memory loss after drinking. Once too much fluorine is ingested for a long time, it will be deposited on teeth and bones, resulting in dental fluorosis and skeletal fluorosis, and more seriously, it will cause damage to the skin, mucous membranes, kidneys or other organs.

[0003] Tea trees are plants that hyper-accumulate fluorine and have a stronger fluorine tolerance than other plants. Tea trees in the natural growth state can accumulate a certain amount of fluorine without showing toxic symptoms. Fluorine is not an essential element for tea trees. Tea trees can still grow normally under fluorine-free conditions without the appearance of element deficiency symptoms. Research shows that low concentrations of fluorine have no obvious effect on the growth of tea trees, but the exogenous application of high concentrations of fluorine will hinder the growth of tea trees and have a toxic effect on them.

[0004] After Li Lixia et al. treated tea seedlings with different concentrations of fluorine, it was found that after 14 days of treatment with 200 mg·L -1 fluorine, the leaves of the tea seedlings showed abscission and darkening, and the roots turned yellow; when the fluorine concentration reached 250 mg·L- 1 1, a large number of leaves fell off, the roots turned black, and these stress symptoms became more obvious with the increase of the fluorine concentration.

[0005] Fang Xinghan et al. also found that when 0.5 - 1 mg·L -1 of fluorine was added to the culture solution for treatment, the hydroponic tea seedlings would show symptoms of excessive fluorine such as yellowing of leaves, stagnation of root and apical bud growth and development after about 3 months; when the tea seedlings were treated with 4 - 8 mg·L -1 fluorine for 1 - 2 months, fluorosis would be found, mainly manifested as scorched young leaves, withered apical buds, abscission of old and diseased leaves, and blackened roots. Tea trees can absorb and accumulate a large amount of fluorine from the soil through their roots, and the fluorine content is 10 - 100 times higher than that of other plants in the same growth environment.

[0006] 40-90% of the fluorine in tea leaves is easily dissolved in the tea soup and further ingested by the human body, which causes the daily fluorine intake of many people who drink brick tea for a long time to far exceed the safe range, resulting in chronic fluorosis such as dental fluorosis, skeletal fluorosis, and increased urinary fluorine. This "tea-drinking type of fluorosis" brings physical and mental damage and pain to people, forcing us to pay attention to the problem of excessive fluorine content in tea leaves.

[0007] In the prior art, there are already methods to inhibit the fluorine absorption of tea trees. For example, Patent CN105993889B mentions the application of using disodium tetrabromofluorescein as an inhibitor of tea tree fluorine absorption, and Patent CN109006118B mentions a planting method of using biosurfactin to reduce the fluorine content in tea tree leaves; among them, when using reagents related to aluminum and iron ions and disodium tetrabromofluorescein and other reagents, there is a risk of heavy metal control; after using calcium ion-related preparations and increasing the soil pH, the growth of tea trees is somewhat inhibited, which in turn affects the yield and the growth trend of tea trees. Moreover, the tea garden soil mass is large, the amount of additives required is large, and the cost is high.

[0008] Potassium is one of the essential macronutrients for plants and is almost involved in all biochemical reactions in tea trees, playing a very important role in the growth and development of tea trees, tea yield, and quality. Potassium deficiency in tea trees will reduce the enzyme activity and metabolic reactions in tea trees, resulting in huge losses in tea quality and yield.

[0009] Gong Xuejiao et al. obtained through hydroponic experiments and establishing a mathematical model that when the potassium content in mature leaves is 10.03 - 10.83 mg·g -1 , and the potassium content in new shoots is 17.72 - 19.11 mg·g -1 , the net photosynthetic rate of tea tree leaves and the chlorophyll synthesis of new shoots are significantly improved, and the optimal hydroponic potassium concentration range is 4.69 - 5.96 mmol / L.

[0010] Potassium deficiency in tea trees will cause the tips and edges of old leaves to turn yellow and brown, curl downward, and there are obvious scorched spots on the lower epidermis, resulting in tissue necrosis, affecting the normal metabolism of tea trees. Potassium deficiency will damage the entire electron transport chain from the donor side of PSII to PSI in tea tree leaves, reducing the photosynthetic electron transport ability. When potassium is deficient, tea tree leaves will increase heat dissipation to protect the leaves from photooxidative damage under strong light. Research has found that when tea trees are treated with low potassium concentrations (0, 100 μmol·L -1 ), their growth is inhibited, the roots, stems, and leaves of tea trees decrease, and the root-shoot ratio increases, which is similar to plants such as wheat, cotton, barley, and corn. In addition, there is also research finding that increasing the potassium treatment concentration or maintaining the potassium content in the mesophyll cells of tea leaves can significantly relieve the drought stress of tea trees and enhance the ability of tea trees to resist stress.

[0011] The main quality components of tea leaves include tea polyphenols, catechins, amino acids, caffeine, and water extracts. The phenol-ammonia ratio is an important component for measuring the quality of fresh tea leaves. Ruan et al. found that potassium application could significantly increase the contents of free amino acids, caffeine, water extracts, etc. in tea plants. Bian Jinlin et al. found that potassium application could significantly reduce the heptanal with a grassy odor in the aroma of tea leaves, while the contents of nonanal and octanal with a floral odor increased, and the total amount of volatile substances of isopentenyl diphosphate and phenylalanine increased. It is speculated that it may be because the accumulation of sugars and the utilization of nitrogen in tea plants are promoted after potassium application, thus increasing the content of phenylalanine in tea plants. Guo Lei found through soil culture that under different potassium concentrations, the free and acid-hydrolyzable low-terpene components increased with the increase of soil potassium concentration, but too high potassium fertilizer concentration would instead decrease the contents of most low-terpene substances; in the hydroponic experiment, it was found that appropriate potassium could promote the synthesis and accumulation of catechins such as EGCG and epicatechin gallate (ECG), and when excessive, the catechin metabolism was too fast and the accumulation amount was small.

[0012] To sum up, although potassium is a conventional element in the growth of tea plants, there is no relevant research linking potassium ions with the inhibition of fluoride accumulation in new tea shoots. In particular, usually, the content of potassium ions in the process of tea plant cultivation is only 106.820 mg / L. The existing technology believes that potassium ions have no special effect after exceeding a certain concentration and may have negative effects.

[0013] Therefore, there is an urgent need for a tea tree fluoride content inhibitor that can enhance the resistance of improved tea tree varieties, help improve the resistance of tea trees to fluoride, thereby reducing fluoride accumulation in new tea shoots and improving the safety of tea leaves, as well as a planting method for inhibiting fluoride accumulation in new tea shoots. Summary of the Invention

[0014] To solve the deficiencies of the existing technology, the purpose of the present invention is to provide a tea tree fluoride content inhibitor and its application, as well as a planting method for inhibiting fluoride accumulation in new tea shoots.

[0015] To achieve the above objectives, the present invention adopts the following technical solutions:

[0016] Application of potassium sulfate as an inhibitor for fluoride accumulation in new tea shoots.

[0017] A hydroponic solution inhibitor for tea tree fluoride content, suitable for the above application, including potassium sulfate to be mixed into the culture solution and having a mass concentration of 435.65 - 871.30 mg·L -1 in the culture solution.

[0018] An inhibitor for inhibiting fluoride content in the culture solution, suitable for the above application, including a culture solution and potassium sulfate mixed in the culture solution with a concentration of 435.65 - 871.30 mg·L -1 in the culture solution.

[0019] Cultured solution, applicable to the tea tree fluorine content hydroponic solution inhibitor or fluorine content-inhibiting cultured solution as described above. The cultured solution comprises the following components, with the balance being water:

[0020] 30 mg·L -1 of (NH4)2SO4,

[0021] 10 mg·L -1 of Ca(NO3)2·4H2O,

[0022] 3.1 mg·L -1 of KH2PO4,

[0023] 40 mg·L -1 of KH2PO4, K2SO4,

[0024] 30 mg·L -1 of CaCl2·2H2O,

[0025] 25 mg·L -1 of MgSO4·7H2O,

[0026] 0.35 mg·L -1 of C 10 H 12 FeN2NaO8,

[0027] 0.1 mg·L -1 of H3BO3,

[0028] 0.76 mg·L -1 of MnSO4·H2O,

[0029] 0.1 mg·L -1 of ZnSO4·7H2O,

[0030] 0.025 mg·L -1 of CuSO4·5H2O,

[0031] 10.8 mg·L -1 of Al2(SO4)3·18H2O,

[0032] 0.05 mg·L -1 of Na2MoO4·2H2O.

[0033] Hydroponic planting method for inhibiting fluorine accumulation in new shoots of tea trees, comprising the following steps:

[0034] A1. Adjust the pH value of the above-mentioned cultured solution to 5.50 ± 0.20;

[0035] A2. Take two-year-old tea seedlings, wash the soil off the tea tree roots, starve them in clean water for 3 - 6 days, and then acclimatize the tea seedlings with a culture solution.

[0036] A3. Plant the tea seedlings in the culture solution and change the culture solution once a week for 4 consecutive weeks.

[0037] A4. Replace the culture solution with the above-mentioned fluorine-inhibiting content culture solution, adjust the pH of the fluorine-inhibiting content culture solution to 5.50 ± 0.20, change the fluorine-inhibiting content culture solution every five days, and repeat three times to obtain pre-treated tea seedlings.

[0038] For the acclimatization culture in step A2 above, the concentration gradients of the culture solution are successively 1 / 8, 1 / 4, 1 / 2, and finally transition to the full-concentration culture solution, with 5 days of acclimatization for each concentration gradient.

[0039] The culture conditions in step A3 above are a temperature of 25 ± 2 °C and a light condition of 12 h light / 12 h darkness.

[0040] The soil cultivation method for inhibiting fluorine accumulation in new shoots of tea trees includes:

[0041] After the temperature rises and the rainfall increases in spring, spray the above-mentioned soil cultivation fertilizer inhibitor on the tea tree leaves to make both the front and back of the leaves fully moist.

[0042] The spraying amount of the above-mentioned soil cultivation fertilizer inhibitor is 90.5 - 120.5 kg / hm 2 .

[0043] The advantages of the present invention are as follows:

[0044] A tea tree fluorine content inhibitor and a planting method for inhibiting fluorine accumulation in new shoots of tea trees according to the present invention combine different application methods of hydroponics and soil cultivation, and deeply study the influence of potassium elements at different concentrations in tea tree planting. Specifically, when the added potassium ion content is 435.65 mg / L, it has an excellent effect on inhibiting fluorine accumulation in new shoots of tea trees.

[0045] As an externally applied potassium element, the addition amount in the present invention is much greater than the application content of potassium fertilizer in the traditional tea tree planting process (106.82 mg / L); the higher concentration of potassium ions added in the present invention not only does not affect the normal growth of tea trees, but also effectively improves the resistance of improved tea tree varieties, enhances the tea tree's resistance to fluorine, reduces the fluorine accumulation in new shoots of tea trees, and further improves the safety of tea tree leaves.

[0046] The present invention effectively reduces the fluorine accumulation in the new shoots of tea plants through potassium element, which is one of the three major elements for fertilizing tea gardens. Compared with other defluorination methods or defluorination additives, it has little impact on the tea garden environment, is green and safe, and helps with subsequent tea tree planting. It effectively solves the problem of excessive fluorine content in Chinese tea, reduces production costs, improves the product quality and market competitiveness of tea, and is of great significance for promoting the rapid development of the tea industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 It is a sectional view of the tea tree leaves of Example 1 and Comparative Examples 1 - 3 ((A) Comparative Example 1, (B) Example 1, (C) Comparative Example 2, (D) Comparative Example 3). DETAILED DESCRIPTION OF THE INVENTION

[0048] The present invention will be specifically introduced below in conjunction with the accompanying drawings and specific embodiments.

[0049] The hydroponic variety used in the examples is "Longjing 43", which is provided by Nanjing Yarun Tea Industry Co., Ltd., Jiangsu Province.

[0050] "Longjing 43" is a national clonal variety selected by the Tea Research Institute of the Chinese Academy of Agricultural Sciences from the Longjing population. It is a national excellent variety. The plant is medium-sized, with a semi-open tree posture, dense branching, and the leaves are obliquely attached. The leaves are oval, dark green in color, flat on the leaf surface, slightly folded inward in the leaf body, with slightly wavy leaf margins, gradually pointed leaf tips, dense and shallow leaf teeth, and medium leaf texture. The bud and leaf are slender, with strong bud and leaf fertility, resistant to picking, and poor tenderness retention. The peak period of one bud and one leaf is in late March.

[0051] Example 1

[0052] M1. Reagent preparation:

[0053] a. The standard tea tree hydroponic solution (culture solution) is prepared as shown in Table 1 below:

[0054] Table 1 Components of the culture solution

[0055]

[0056] b. The culture solution for inhibiting fluorine content includes potassium sulfate and the standard tea tree hydroponic solution in Table 1. The concentration of potassium sulfate in the hydroponic solution inhibitor is 435.65 mg·L -1 .

[0057] M2. Hydroponic planting method for inhibiting fluorine accumulation in tea tree new shoots:

[0058] Step 1. Prepare 120 L of the culture solution according to Table 1, adjust the pH to 5.50 ± 0.20, and divide it into 12 plastic pots with a capacity of 12 L, 10 L per pot;

[0059] Step 2: Tea seedling transplanting and acclimation culture: Select two-year-old tea seedlings of the "Longjing 43" tea tree variety, and wash the soil off the tea tree roots. After 3 - 6 days of starvation in clear water, acclimate and culture them with a culture solution, with gradient concentrations of 1 / 8, 1 / 4, 1 / 2 in sequence, and finally transition to the full-concentration culture solution, with 5 days of acclimation for each concentration.

[0060] Step 3: Plant the acclimated tea seedlings in the culture solution, with 20 tea trees planted in each pot. Culture conditions: temperature 25 ± 2°C, light cycle 12 h light / 12 h dark; change the culture solution once a week, and continuously culture for 4 weeks; proceed to Step 4.

[0061] Step 4: Potassium treatment: Add potassium sulfate to the culture solution to make the final potassium sulfate content in the culture solution 435.65 mg / L, obtaining a culture solution with inhibited fluoride content, adjust the pH to 5.50 ± 0.20, change the culture solution with inhibited fluoride content once every five days, and repeat three times; obtain the pre-treated tea seedlings; proceed to Step 5.

[0062] Step 5: Sampling and detection: After 30 days of culture, take various tissue parts of the tea seedlings for various index detections.

[0063] Example 2

[0064] Change the concentration of potassium sulfate in the culture solution with inhibited fluoride content from 435.65 mg / L in Example 1 to 871.30 mg / L, and the rest is the same as in Example 1.

[0065] Comparative Example 1

[0066] The difference between Comparative Example 1 and Example 1 is that it does not go through Step 4.

[0067] Comparative Example 2

[0068] The difference between Comparative Example 2 and Example 1 is that 16 mg·L -1 NaF is added to the culture solution, the pH is adjusted to 5.50 ± 0.20, and it does not go through Step 4.

[0069] Comparative Example 3

[0070] The difference between Comparative Example 3 and Example 1 is that 16 mg·L -1 NaF is added to the culture solution, and the pH is adjusted to 5.50 ± 0.20.

[0071] Index detection of Example 1 and Comparative Examples 1 / 2 / 3 under hydroponic conditions:

[0072] 1. Fluoride content and transport coefficient in various tissue parts of the tea tree

[0073] The one-bud-two-leaf, three-to-six-leaf, stem, and root of tea seedlings dried at 80 °C were fully ground into powder. After passing through a 2-mm sieve, 0.5 g of the sample was weighed into a 50-mL centrifuge tube, 30 mL of ultrapure water was added, and the tissue was completely immersed by inverting up and down. Then it was placed in a boiling water bath at 100 °C for extraction for 30 min. After taking it out, it was cooled to room temperature and centrifuged at 25 °C and 4000 rpm for 15 min. The supernatant was taken as the test solution.

[0074] 15 mL of the test solution was pipetted into a beaker, 15 mL of fluoride ion strength buffer solution was added, and after thorough mixing, it was measured with a fluoride ion selective electrode (Thermo Orin 9609BNWP). All measurements were repeated 3 times.

[0075] To further understand the effects of different treatments on fluoride transport in tea plants, based on the fluoride accumulation data in the one-bud-two-leaf, three-to-six-leaf, root, and stem of tea plants, the ratio of the fluoride content in the above-ground part to the fluoride content in the underground part was calculated to obtain the fluoride transport efficiency of tea plants under each treatment.

[0076] According to the above method, the various indexes of the tea seedlings in Example 1 and Comparative Examples 1-3 were measured, and the data in Table 2 below were obtained:

[0077] Table 2 Fluoride content and transport coefficient in various tissue parts of tea plants under different treatments

[0078]

[0079] As can be seen from Table 2, fluoride accumulation in tea plants is in the leaves, and the fluoride content in the leaves is 60-70 times higher than that in the roots and stems. Comparing Example 1 and Example 2, it can be seen that the higher the potassium concentration, the lower the fluoride content in the new shoots of tea plants; compared with Comparative Example 1, the fluoride content in the one-bud-two-leaf of the tea plants in Example 1 and Example 2 decreased significantly, and the fluoride content in the three-to-six-leaf, stem, and root increased to a certain extent. After treating the tea plants with 16 mg / L fluoride, the fluoride content in each tissue of the tea plants increased significantly. The fluoride transport efficiency of the tea plants in Comparative Example 3 decreased significantly compared with that in Comparative Example 2, indicating that the decrease in the fluoride content in the one-bud-two-leaf may be due to potassium alleviating the redistribution of the already accumulated fluoride in the mature leaves.

[0080] 2. Chlorophyll content in tea plant leaves under fluoride-potassium interaction treatment

[0081] Take tea plant leaves, cut them into pieces, and put 0.1 g into a sealed container with 10 mL of the mixed solution, and soak it in the dark until the leaves turn completely white. Use a microplate reader to measure the absorbance values of the extract at 663 nm and 645 nm. Using the acetone-ethanol-water mixed extract as a control, finally calculate the chlorophyll content, as shown in Table 3 below.

[0082] Calculation formula: Chlorophyll a (mg·g -1 )=(12.7A 663 -2.69A645 ) × [v / (1000 × W)]

[0083] Chlorophyll b (mg·g -1 ) = (22.7A 645 - 4.68A 663 ) × [v / (1000 × W)]

[0084] Total chlorophyll = Chlorophyll a + Chlorophyll b

[0085] Chlorophyll a / b = Chlorophyll a / Chlorophyll b

[0086] Among them, A 663 and A 645 are the absorbances at wavelengths of 663 nm and 645 nm respectively, V is the volume of the extraction solution (ml), and W is the fresh weight of the leaves (g).

[0087] Table 3 Chlorophyll content in tea tree leaves under the interaction treatment of fluorine - potassium

[0088]

[0089]

[0090] Table 3 shows the changes in the chlorophyll content of tea tree leaves under the interaction treatment of different concentrations of fluorine - potassium. It can be found that: in Example 1, the contents of chlorophyll a and chlorophyll b in tea tree leaves are significantly higher than those in Comparative Example 1; the chlorophyll content in Example 2 increases compared with Comparative Example 1, but not significantly, indicating that the treatment with 435.65 mg / L potassium can better alleviate the damage of fluorine to the chlorophyll of tea tree leaves. The chlorophyll content in Comparative Example 3 increases compared with Comparative Example 2, but the difference is not significant. It shows that the exogenous potassium treatment can effectively alleviate the damage of fluorine to the chlorophyll of tea tree shoots cells.

[0091] Fluorine is not an essential element for tea trees. Low - dose fluorine has no significant effect on the growth of tea trees, but high - dose fluorine will inhibit the growth of tea trees and cause toxic effects on them. The stress of fluorine on tea trees is mainly manifested in the inhibition of metabolism and the damage to cell structure. Excessive fluorine damages the chloroplasts and cell membrane systems of tea leaves, thus inhibiting photosynthesis, resulting in the inability of tea trees to carry out normal metabolism and affecting the growth and development of tea trees.

[0092] Research has found that as the concentration of fluorine treatment increases, the chlorophyll content in tea tree leaves gradually decreases, and the chlorophyll a / b value is less than that of the control. It shows that the main reason for the decrease in the chlorophyll content of tea tree leaves is the degradation of chlorophyll b by chlorophyllase. In Comparative Example 2, the chlorophyll content in tea tree leaves decreases and chlorophyll b is more sensitive to fluorine stress. The decrease in chlorophyll content caused by fluorine treatment may be due to the fact that after fluorine enters the chloroplast, it combines with Mg 2+Combination damages the molecular structure of chlorophyll, resulting in a decrease in chlorophyll content. After potassium treatment, the chlorophyll content in tea tree leaves increased and was significantly greater than that of the control. It indicates that exogenous application of a certain amount of potassium can promote chlorophyll synthesis and alleviate the inhibitory effect of fluorine on chlorophyll synthesis.

[0093] 3. Photosynthetic parameters of tea trees

[0094] The photosynthetic parameters of the third functional leaf of tea seedlings were measured using a Li-6400 photosynthesis analyzer: net photosynthetic rate (Pn), transpiration rate (Tr), intercellular carbon dioxide concentration (Ci), and stomatal conductance (Gs).

[0095] Measured light intensity: 300 μmol·m -2· s -1 ; Temperature 25 ± 2 °C; Air CO2 concentration 380 ± 20 μmol·mol -1 . Each treatment was repeated 10 times.

[0096] Table 4 Photosynthetic parameters of tea trees under fluorine-potassium interaction treatment

[0097]

[0098] Table 4 shows the changes in the photosynthetic parameters of tea trees under fluorine-potassium interaction treatment: After potassium treatment, the net photosynthetic rate, transpiration rate, and stomatal conductance of tea trees in Example 1 and Example 2 were significantly increased compared with those in Comparative Example 1, and the promotion effect of 435.65 mg / L potassium treatment was more significant. After fluorine treatment, the net photosynthetic rate, transpiration rate, and stomatal conductance of tea trees in Comparative Example 3 were significantly increased compared with those in Comparative Example 2, and the intercellular CO2 concentration was significantly decreased. It indicates that a potassium treatment concentration of 435.65 mg·L -1 can greatly improve the net photosynthetic rate of tea trees. The accumulation of dry matter in plants mainly depends on the photosynthesis of tea trees, and the net photosynthetic rate is an important indicator to measure the speed of tea tree photosynthesis. Potassium ions are crucial for the photosynthetic electron transfer ability in plant photosynthesis. Potassium deficiency damages the entire electron transfer chain from the PSⅡ donor side to PSⅠ in tea tree leaves and reduces the photosynthetic electron transfer ability. Therefore, sufficient potassium ions can maintain the normal progress of tea tree photosynthesis. Leaves are the main organs of plant photosynthesis, and chlorophyll is the most critical photosynthetic pigment among them. Chlorophyll plays a role in absorbing and converting light energy into biochemical energy in photosynthesis and is the energy source for the efficient operation of photosynthesis. It shows that appropriate potassium can enhance the photosynthesis of tea trees by promoting the formation of chlorophyll in tea tree leaves and alleviate the stress effect of fluorine on tea trees.

[0099] The transpiration rate can reflect the intensity of plant photosynthesis over a period of time from the side. The transpiration rate of tea plants increased significantly after potassium treatment, which was consistent with the net photosynthetic rate, indicating that exogenous potassium application could enhance the photosynthesis of tea plants, and the effect of 435.65 mg / L potassium treatment concentration was the most significant. The intercellular CO2 concentration of tea plants decreased significantly after potassium treatment.

[0100] CO2 in the air is the main carbon source for tea plants to carry out photosynthesis, and the intercellular CO2 concentration generally gradually increases with the prolongation of stress. It was found in the experiment that the intercellular CO2 of tea plants decreased significantly after potassium treatment, indicating from the side that the photosynthetic rate of tea plants increased, and CO2 was converted into organic matter through photosynthesis. The promotion effect of Example 1 was stronger than that of Example 2.

[0101] Stomatal conductance is the conductance of plant leaves to carbon dioxide and water vapor. The stomatal conductance also increased significantly after the potassium treatment concentration, 435.65 mg·L -1 Potassium treatment can effectively alleviate the stomatal closure phenomenon of tea plants under high-concentration fluoride treatment, and accelerate the conduction of carbon dioxide and water vapor in tea plant leaves. The enhancement of transpiration, the decrease of intercellular CO2 concentration and the enhancement of stomatal conductance all illustrate from the side that 435.65 mg·L -1 The enhancement of photosynthesis of tea plants by potassium under fluoride stress.

[0102] As Figure 1 shown, it is the change of the ultrastructure of tea plant leaves under the fluorine-potassium interaction treatment.

[0103] Take the third leaf of the tea seedlings, cut a leaf block (2 mm×2 mm) 3 mm away from the leaf vein in the middle of the leaf with a blade, and quickly place it in a 2.5% glutaraldehyde fixative. Vacuumize to completely immerse the leaf block in the fixative, and fix it in an environment of 0-4°C for 24 h. Then rinse the sample 3 times with phosphate buffer (pH 7.2), fix it with 1% osmium tetroxide for 1 h, wash it 3 times with distilled water, treat it with 50%, 70%, 80%, and 100% acetic acid for 10 min respectively, replace it with acetone for 24 h, and longitudinally prepare ultrathin sections (thickness ≤100 nm) with an ultramicrotome. Observe under a transmission electron microscope and collect images for analysis.

[0104] In the figure, (A) is Comparative Example 1, (B) is Example 1, (C) is Comparative Example 2, and (D) is Comparative Example 3.

[0105] It can be seen that:

[0106] The cell organelles in Comparative Example 1 were evenly distributed, and there were some starch grains in the chloroplasts (Figure A).

[0107] There was no obvious change in the ultrastructure of the tea plant leaves treated in Example 1, and the distribution of chloroplasts in the leaves expanded and the grana lamellae gaps became compact (Figure B).

[0108] A large number of osmiophilic granules appeared in the tea tree leaves treated in Comparative Example 2, and the grana lamellae of the chloroplasts became wider and vacuoles appeared in the chloroplasts (Figure C).

[0109] In the chloroplasts treated in Comparative Example 3, the grana lamellae became compact again, the number of chloroplasts increased and there was no vacuole phenomenon (Figure D).

[0110] Observing the subcellular structure of tea tree leaves, it can be found that when the tea tree is under fluorine stress, the number of chloroplasts in the tea tree leaves decreases significantly, the volume of starch grains increases, and the cell structure of the tea tree is damaged. This is consistent with the change results of chlorophyll content.

[0111] Research shows that after treating tea seedlings with 10 - 50 mg / L fluorine, a large amount of starch grains accumulate in the tea tree leaf cells. As the source of photosynthesis, the weakening of photosynthesis will lead to the deposition of starch grains in the chloroplasts. The accumulation of starch grains in the chloroplasts will also compress the proportion of thylakoids in the chloroplasts, squeezing the thylakoid lamellae, thus leading to the weakening of photosynthesis. In Example 1, the chloroplasts in the tea tree leaves increased and the grana lamellae were arranged tightly, indicating that a potassium concentration of 435.65 mg / L can promote the formation of chlorophyll in the tea tree leaves and relieve the toxicity of fluorine to the new shoots of the tea tree.

[0112] Example 3

[0113] N1. Preparation of a soil culture fertilizer inhibitor for the fluorine content of tea trees:

[0114] Take potassium sulfate and dissolve it in water to prepare a potassium sulfate solution with a mass concentration of 44.2 mg·L -1 solution.

[0115] N2. A soil culture planting method for inhibiting the fluorine accumulation in the new shoots of tea trees:

[0116] After the temperature rises and the rain increases in spring, spray the potassium sulfate solution on the tea tree leaves to make the front and back of the leaves fully moist. The spraying amount per mu of tea garden is 90.5 kg / hm 2 ;

[0117] After fertilization, carry out daily field management.

[0118] The specific field management includes:

[0119] Apply 15 - 25 kg of special tea fertilizer per 667 square meters in the tea garden, and apply 50 kg of special tea fertilizer per 667 square meters in the mature tea garden. Open a ditch (the ditch depth is 3 - 5 cm) 15 - 20 cm away from the tea tree roots and apply it, paying attention to covering the soil while applying to prevent the loss of fertilizer efficiency. Spring is also a key period for fertilizing the tea garden, and green manure can be planted in the tea garden to improve the soil fertility.

[0120] Prevention and control of diseases, pests and weeds: To ensure the quality of tea leaves, pesticides should be used sparingly or not at all in spring. During the spring tea picking period, when pests such as aphids, tea caterpillars and black tea thrips are in the initial stage of occurrence, the occurrence of pests and diseases in the tea garden should be observed regularly, and a prevention and control plan should be formulated in a timely manner. Ways such as light trapping, color trapping and sex pheromone trapping can be used to control pests and diseases in the tea garden. When the pests and diseases reach a certain level, biological pesticides, botanical pesticides, mineral source pesticides, etc. can be used for prevention and control. For weed control, chemical herbicides should not be used, and manual or mechanical methods can be used for weeding, such as weeding with a weeding machine, tilling with a plough, and covering the tea garden.

[0121] Reasonable pruning: Pruning of tea trees in spring mainly includes shaping pruning of young tea trees, light pruning of picking tea gardens, and pruning of tea gardens affected by drought and freezing damage. Shaping pruning means that when the seedling height is 25 - 30 cm and there are 1 - 2 branches, cut off the excess part at the top 15 - 20 cm above the ground and leave the lateral branches. Light pruning generally cuts off the overgrown branches and diseased and insect branches on the canopy surface, and the cutting depth is 2 - 5 cm. For the pruning of tea gardens affected by drought and freezing damage, the cutting opening should be 1 - 2 cm deeper than the damaged part. Tea tree pruning is required to be carried out when the temperature is stable above 15 °C, and in principle, it is carried out before the spring buds germinate or after the spring tea is finished.

[0122] Timely ditch cleaning and drainage: There is a lot of rain in spring. If the drainage in the tea garden is not smooth, the tea trees are prone to waterlogging damage, resulting in root rot, causing late sprouting of tea buds and yield reduction. Therefore, it is necessary to open ditches for drainage in a timely manner, clean and dredge the drainage ditches, ensure that the groundwater level is below 1 meter, and make the tea garden dry after the rain stops without water accumulation. Guard against the "late spring cold": The early spring temperature is unstable, and cold snaps often come. According to the specific weather forecast, measures such as covering, irrigation, and smoking should be taken for protection before the strong cold snap occurs.

[0123] Example 4

[0124] The difference between this example and Example 3 is that the spraying amount per mu of the tea garden is 120.5 kg / hm 2 。

[0125] Comparative Example 4

[0126] The difference between this comparative example and Example 3 is that the spraying amount per mu of the tea garden is 40.5 kg / hm 2 。

[0127] Table 5 Fluoride content in new shoots of soil-cultivated tea trees

[0128]

[0129] According to the comparison between Example 3 and Comparative Example 4, it can be known that, compared with Comparative Example 4, the fluorine content in the new shoots (one bud with two leaves) of Example 3 decreased by 15.7%, and the fluorine accumulation in the new shoots of tea plants in Example 4 decreased significantly compared with Comparative Example 4, but was higher than that in Example 3. It shows that potassium sulfate can effectively reduce the fluorine accumulation in the new shoots of tea plants, and the application rate of 90.5 kg / hm 2 has a better effect.

[0130] As described above, although the present invention has been shown and described with reference to specific preferred embodiments, it should not be construed as a limitation of the present invention itself. Various changes in form and detail may be made without departing from the spirit and scope of the present invention defined by the appended claims.

Claims

1. An inhibitor for the fluoride content in the hydroponic solution of tea plants, characterized in that, The inhibitor of the fluorine content in the tea plant hydroponic solution is mixed into the culture solution, and potassium sulfate with a mass concentration of 435.65 - 871.30 mg·L -1 is used.

2. Fluoride content-inhibiting culture solution, characterized in that, including a culture solution and potassium sulfate with a concentration of 435.65 - 871.30 mg·L -1 in the culture solution; The culture solution comprises the following components, with the balance being water: 30 mg·L -1 of (NH4)2SO4, 10 mg·L -1 of Ca(NO3)2·4H2O, 3.1 mg·L -1 of KH2PO4, 40mg·L -1 of KH2PO4, K2SO4, 30 mg·L -1 of CaCl2·2H2O, 25 mg·L -1 of MgSO4·7H2O, 0.35mg·L -1 of C 10 H 12 FeN2NaO8, 0.1mg·L -1 of H3BO3 0.76 mg·L -1 of MnSO4·H2O, 0.1 mg·L -1 of ZnSO4·7H2O, 0.025 mg·L -1 of CuSO4·5H2O, 10.8 mg·L -1 of Al2(SO4)3·18H2O, 0.05 mg·L -1 of Na2MoO4·2H2O 3. Hydroponic cultivation method for inhibiting fluorine accumulation in new shoots of tea plants, characterized in that, Comprising the following steps: A1. Adjust the pH value of the culture solution described in claim 2 to 5.50 ± 0.20; A2. Take two-year-old tea seedlings, wash the soil off the tea tree roots, starve them in clear water for 3 to 6 days, and then domestically cultivate the tea seedlings with the culture solution; A3. Plant the tea seedlings in the culture solution, change the culture solution once a week, and continuously culture for 4 weeks; A4. Replace the culture solution with the fluorine content-inhibiting culture solution described in claim 2, adjust the pH of the fluorine content-inhibiting culture solution to 5.50 ± 0.20, change the fluorine content-inhibiting culture solution once every five days, and repeat three times to obtain pre-treated tea seedlings.

4. The hydroponic cultivation method according to claim 3, wherein For the domestic cultivation in step A2, the concentration gradients of the culture solution are successively 1 / 8, 1 / 4, 1 / 2, and finally transition to the full-concentration culture solution, and each concentration gradient is domesticated for 5 days.

5. The hydroponic cultivation method according to claim 3, characterized in that: The culture conditions in step A3 are a temperature of 25 ± 2 °C and a light condition of 12 h light / 12 h darkness.

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