Application of a preservative in citrus tree preservation and storage

Abstract

The present invention relates to fruit preservation technology, and in particular to an application of a preservative in the preservation of citrus fruits on the tree and in storage. In particular, the present invention relates to a method for treating citrus fruits, the method comprising: soaking the fruits in a solution containing isooctyl loropylacetate, or spraying the fruits with a solution containing isooctyl loropylacetate; the treatment is a treatment on the tree or a post-harvest treatment. The present invention also relates to the use of isooctyl loropylacetate for preserving citrus fruits on the tree or after harvest, or improving the internal and / or external quality of citrus fruits.

Description

Technical Field

[0001] The invention relates to a fruit preservation technology, and in particular to an application of an antiseptic preservative in the preservation of citrus fruits on the tree and in storage. Background Art

[0002] 2,4-Dichlorophenoxyacetic acid (2,4-D) is the most widely used chemical preservative in the post-harvest commercial processing of citrus. As one of the most effective preservatives, 2,4-D can significantly keep citrus fruit stems fresh, delay calyx senescence (Cronjé et al. 2004), reduce fruit weight loss, maintain fruit color and firmness (Sonkar et al. 2009), and extend storage life. Previous studies have shown that 2,4-D treatment can significantly slow down the decline in the content and activity of antifungal substances in yellow peel, significantly inhibit pathogen infection and the development of decay (Ben-Yehoshua et al 1995; Ma et al 2014), without affecting the internal quality of stored fruits (El-Otmani and Coggins Jr. 1991). Ma Qiaoli (2014) used Olinda summer orange (Citrus sinensis (L.) Osbeck) as the material and preliminarily analyzed the mechanism of 2,4-D delaying citrus fruit pedicle shedding through transcriptomics and proteomics analysis. In addition, the total amount of wax on the surface of the peel did not change significantly before and after 2,4-D treatment, but the wax composition and proportion, and the ultrastructure of the wax on the surface of the peel all changed significantly.

[0003] In recent years, people have found that the intermediate dioxins produced during the production of 2,4-D are highly carcinogenic and are prohibited from use in the production of Grade A green food. They are also less soluble in water and have a longer half-life, making them difficult to be absorbed and degraded by the soil under natural conditions. The EU has now clearly restricted the use of 2,4-D in fruit preservation, and 2,4-D is likely to be restricted or banned in the near future. In view of the adverse effects of 2,4-D on human health and environmental safety, its application in the citrus industry is limited. Therefore, it is of great significance to research and develop a new green citrus preservative that can replace 2,4-D. Summary of the invention

[0004] The inventors have found that clofopyralid (Clofloxacin) is an efficient and environmentally friendly alternative to 2,4-D for post-harvest storage and preservation. The inventors found clofopyralid isooctyl ester among the ester agents that are widely used in production. As an organic heterocyclic selective systemic conduction agent, it has similar chemical functions to clofopyralid. Both can significantly delay the senescence of citrus fruit pedicles and extend the storage period of citrus. The preservation effect is equivalent to or even better than 2,4-D, and it has no adverse effect on the intrinsic quality of citrus fruits that have reached commercial maturity, and there is no significant difference compared with 2,4-D. At the same time, the inventors found that the treatment of citrus with isooctyl clofopyralid on the tree can significantly delay the color change of the fruit, improve the hardness of the fruit, improve the intrinsic quality of the fruit, and prolong the fruit-bearing period; moreover, for fruits that have not completely changed color, isooctyl clofopyralid can significantly reduce the unfavorable color change symptoms of the fruit caused by the treatment of isooctyl clofopyralid. On the other hand, compared with isooctyl clofopyralid, isooctyl clofopyralid has a lower production cost and lower environmental risk, and is a more environmentally friendly, less toxic and effective substitute for 2,4-D. Therefore, the present application provides the following inventions:

[0005] In one aspect, the present application provides a method for treating citrus fruit, the method comprising: soaking the fruit in a solution containing clofopyralid or spraying the fruit with a solution containing clofopyralid; the treatment is a tree-based treatment or a post-harvest treatment.

[0006] In certain embodiments, the solution comprising fluopicolide is an aqueous solution.

[0007] In certain embodiments, the solution comprises isooctyl fluroxypyraclostrobin, water, and a cosolvent (e.g., ethanol);

[0008] In certain embodiments, the concentration of clofopyralid in the solution is 1 mg / L-500 mg / L (e.g., 1 mg / L-25 mg / L, 25 mg / L-50 mg / L, 50 mg / L-100 mg / L, 100 mg / L-200 mg / L, 200 mg / L-300 mg / L, 300 mg / L-400 mg / L, or 400 mg / L-500 mg / L, e.g., 25 mg / L-50 mg / L).

[0009] In the present invention, the isooctyl loquat solution used for the above treatment can be prepared by the following method: weigh a certain mass of isooctyl loquat and a cosolvent (such as ethanol, such as 5% anhydrous ethanol), and add them into a certain volume of water.

[0010] The processing method of the invention can be used for on-tree preservation and post-harvest preservation of citrus fruits.

[0011] In some embodiments, the treatment is a tree-staying treatment, and the method comprises: spraying the solution on the crown of the citrus fruit tree during the fruit color breaking period. In some embodiments, the treatment is sprayed twice, with an interval of 14 to 16 days (e.g., 15 days). The fruit color breaking period refers to the period when the fruit turns from green to yellow.

[0012] In some embodiments, the treatment is post-harvest treatment, and the method comprises: soaking the fruit in the solution. In some embodiments, the soaking time is 1 to 3 minutes (e.g., 2 minutes). In some embodiments, the fruit is naturally dried after soaking.

[0013] The present invention is carried out under standard atmosphere and pressure.

[0014] In the present invention, the term "citrus" refers to plants of the genus Citrus in the Rutaceae family, including but not limited to navel oranges (such as London navel oranges, Newhall navel oranges), sugar oranges (sugar oranges), ponkan, and satsuma.

[0015] In another aspect, the present application provides the use of clofopyralid 2-ethylhexyl for preserving citrus fruits or improving the intrinsic and / or extrinsic quality of citrus fruits, wherein the preservation is tree preservation or post-harvest preservation. In the present invention, the term "preservation" refers to extending the storage period or shelf life (especially the room temperature shelf life) of the fruit.

[0016] In certain embodiments, clofopyralid 2-ethylhexyl can be used for one or more of the following purposes: reducing fruit rot, maintaining the freshness of fruit stems, increasing the hardness of fruit skin, delaying fruit coloring, extending the fruit bearing period, extending the fruit storage period, reducing fruit acidity, increasing fruit sweetness, reducing fruit odor, enhancing fruit flavor, reducing fruit slag-forming properties, and increasing fruit juice yield.

[0017] In certain embodiments, the citrus is selected from the group consisting of navel oranges (eg, London navel oranges, Newhall navel oranges), sugar oranges, ponkan, and satsuma oranges.

[0018] In certain embodiments, the use is achieved by any of the methods described above.

[0019] The application also provides a citrus fruit preservative, the preservative being a solution comprising isooctyl clofopyralid, water and an optional cosolvent (e.g., ethanol). In certain embodiments, in the solution, the concentration of isooctyl clofopyralid is 1 mg / L-500 mg / L (e.g., 1 mg / L-25 mg / L, 25 mg / L-50 mg / L, 50 mg / L-100 mg / L, 100 mg / L-200 mg / L, 200 mg / L-300 mg / L, 300 mg / L-400 mg / L or 400 mg / L-500 mg / L, e.g., 25 mg / L-50 mg / L or 25 mg / L-200 mg / L).

[0020] Compared with the prior art, the advantages of the present invention are:

[0021] 1. It can significantly reduce the symptoms of unfavorable color change of fruits after harvest caused by clofopyralid treatment. Clofopyralid is a potential preservative for citrus that has been discovered by the inventors, but in actual applications, it is found that the preservation effect of citrus that have completely changed color after treatment with clofopyralid is equivalent to that of 2,4-D treatment, and the appearance and intrinsic quality of the fruit can be better maintained, and there is no significant difference between the two effects. However, when citrus that have not completely changed color are treated with clofopyralid, it will cause the citrus to be unable to change from orange-yellow to orange-red after harvest. The present invention significantly alleviates this symptom while ensuring the effect of use, and the fruit can change color normally after harvest.

[0022] 2. The use concentration was optimized, and the effective use concentration range of cloflupyr isooctyl for post-harvest treatment of citrus was determined. The inventors screened the use concentration of cloflupyr isooctyl and found that within the concentration range of 1 mg / L-500 mg / L, the preservation effect of cloflupyr isooctyl on citrus fruit pedicles at a concentration as low as 25 mg / L was equivalent to that of the same concentration of cloflupyr, and it could better maintain the appearance and intrinsic quality of the fruit. The application of the invention can significantly reduce the amount of chemical preservatives used in the commercial treatment of fruits after harvest and reduce the residue of the agent.

[0023] 3. The application scope of clofopyralid in citrus preservation has been expanded, and it has been applied to on-tree preservation for the first time. After two years of repeated tests, the effect of clofopyralid in preserving London late navel oranges and sugar oranges on the tree, and preserving Newhall navel oranges and ponkan after harvest has been verified. This shows that the preservation effect of clofopyralid on citrus is stable, the possibility of negative effects is low, and it can be used with confidence.

[0024] 4. Flupyralid 2-ethylhexyl ester has lower toxicity and soil degradation half-life than 2,4-D and flupyralid. Studies have shown that the acute oral LD50 (median lethal dose) of flupyralid original drug for rats is 2405 mg / kg, while the acute oral LD50 of flupyralid 2-ethylhexyl ester for mice is>5000 mg / kg, while the acute oral LD50 of 2,4-D original drug for rats is>700 mg / kg, and the acute oral LD50 for mice is>439 mg / kg. It can be seen that flupyralid 2-ethylhexyl ester is less toxic than flupyralid and 2,4-D. It is reported that the degradation half-life of clofopyralid in soil is 3.80-8.20 days, the degradation half-life of clofopyralid in soil is 7.99-9.92 days, and that of 2,4-D is about 20.2 days. Therefore, clofopyralid is more easily degraded in soil. In addition, clofopyralid is a product of esterification of clofopyralid, which is a chemical structure modification. Therefore, in theory, it should have better fat solubility and be easier to penetrate biological membranes. In summary, the application of clofopyralid in citrus preservation can greatly reduce consumers' concerns about food safety and environmental pollution.

[0025] 5. Economic and environmentally friendly. From the perspective of chemical synthesis, both clofopyralid and isooctyl clofopyralid must undergo fluorination, amination, hydroxylation, and condensation reactions. The production process of clofopyralid is to saponify with alkali and acidify with acid after the fourth step of condensation reaction. During this process, a large amount of alkaline and acidic wastewater will be generated, which puts great pressure on environmental protection treatment. However, isooctyl clofopyralid only undergoes one step of ester exchange after condensation to obtain the product. The solvent used is an organic solvent, which can be recycled and reused, and does not produce a large amount of wastewater. The synthesis process has relatively few steps, and the treatment of the three wastes is relatively easy. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The rot rate of Wenzhou mandarin oranges stored after harvest in Example 1 is shown.

[0027] Figure 2 The senescence rate of the fruit pedicles of the post-harvest stored Wenzhou mandarin oranges in Example 1 is shown.

[0028] Figure 3 The appearance of Newhall navel orange fruit treated with isooctyl fluroxypyraclostrobin, fluroxypyraclostrobin and 2,4-D in Example 2 is shown.

[0029] Figure 4 The appearance of the fruit pedicles of Newhall navel oranges treated with isooctyl fluroxypyraclostrobin, fluroxypyraclostrobin and 2,4-D in Example 2 is shown.

[0030] Figure 5 The decay rate of Newhall fruit during postharvest storage in Example 2 is shown.

[0031] Figure 6 The senescence rate of Newhall fruit pedicles during postharvest storage in Example 2 is shown.

[0032] Figure 7 The appearance of mandarin orange fruit treated with isooctyl fluroxypyraclostrobin, fluroxypyraclostrobin and 2,4-D in Example 3 is shown.

[0033] Figure 8 The rot rate of ponkan fruit during postharvest storage in Example 3 is shown.

[0034] Fig. 9 The senescence rate of the pedicels of the postharvest stored ponkan fruits in Example 3 is shown.

[0035] Fig.10 The color difference values ​​of the Lunwan navel orange fruits treated with tree retention in Example 4 are shown.

[0036] Fig.11 The peel hardness of the late navel orange treated with fluroxypyraclostrobin for 120 days is shown in Example 4.

[0037] Fig.12 The color difference of the sugar oranges treated with tree residues in Example 5 is shown. DETAILED DESCRIPTION

[0038] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0039] In the following examples, the fruit pedicle senescence rate is represented by the percentage of the number of fruits with senescent fruit pedicles in the later storage period to the remaining total number of fruits, and the statistics and calculation of the fruit pedicle senescence rate of the water control fruit pedicle senescence number are performed when the fruit pedicle senescence number is about half, and the calculation of the fruit rot rate is performed by counting the remaining fruits at the same time, and the fruit rot rate is represented by the percentage of the remaining fruit number to the original total number of fruits. Excel was used to process the data, and R studio software was used to perform a significant difference analysis (P<0.05), and the labels in the bar graph (such as a, b, c, d, etc.) were significant marks.

[0040] The structure and molecular formula of clofopyralid isooctyl ester are as follows:

[0041] Chinese name: Fluroxypyr-meptyl; English name: Fluroxypyr-meptyl; Molecular formula: C 15 H 21 Cl2FN2O3; molecular weight: 367.24; CAS number: 81406-37-3

[0042]

[0043] Example 1: Application of 2-ethylhexylclofopyralid in postharvest storage and preservation of Wenzhou mandarin oranges.

[0044] In order to verify the uniqueness of the preservative effect of clofopyralid among postharvest ester agents, the postharvest preservative 2,4-D butyl ester, the fungicide pyraclostrobin and the laboratory commonly used ester methyl acetate were selected as experimental treatments, clean water was selected as the control treatment, and Wenzhou mandarin oranges were selected as experimental materials. The postharvest storage experimental steps are as follows:

[0045] 1. Solution preparation: Weigh 2,4-D butyl ester, isooctyl clofopyralid, pyraclostrobin and methyl acetate, respectively, and dissolve them in 60 liters of tap water to prepare 200 mg / L 2,4-D butyl ester solution, isooctyl clofopyralid solution, pyraclostrobin solution and methyl acetate solution, and select tap water as the control treatment.

[0046] 2. Experimental treatment: Select healthy Wenzhou mandarin oranges of uniform size and color, and soak the fruits in the above four solutions and tap water for 2 minutes. After natural drying, bag the fruits and store them at room temperature for 1 month.

[0047] 3. The experimental results are as follows:

[0048] Figure 1 Shows the decay rate of Satsuma mandarin orange fruit during post-harvest storage. Figure 2 The figure shows the senescence rate of Wenzhou mandarin orange pedicles during post-harvest storage. Treatment abbreviations and codes: CK: clean water; 2,4-D: 2,4-D butyl; YXZ: 2-ethylhexyl flupyr; BMZ: pyraclostrobin; YSZ: methyl acetate. (Abbreviations and codes are self-selected)

[0049] Depend on Figure 2 It can be seen that on the 15th day after harvest, the senescence rate of the fruit pedicles treated with 2,4-D, pyraclostrobin and methyl acetate was not significantly different from that of the water control treatment, while the senescence rate of the fruit pedicles treated with isooctyl clofopyralid was lower than that of the water treatment and 2,4-D treatment, with significant differences (p<0.05). On the 30th day after harvest, the senescence rate of the fruit pedicles treated with pyraclostrobin was not significantly different from that of the water treatment; the senescence rate of the fruit pedicles treated with methyl acetate was higher than that of the water treatment, with significant differences (p<0.05); the senescence rate of the fruit pedicles treated with 2,4-D was lower than that of the water treatment, with significant differences (p<0.05); the senescence rate of the fruit pedicles treated with isooctyl clofopyralid was lower than that of the water treatment and 2,4-D treatment, with significant differences (p<0.05).

[0050] Experiments show that among many ester agents, only clofopyralid ethyl ester and 2,4-D butyl ester treatment can significantly reduce the senescence rate of citrus fruit pedicles, and the effect of clofopyralid ethyl ester treatment is better than that of 2,4-D butyl ester treatment.

[0051] Example 2: Application of 2-ethylhexyl fluazifop in postharvest storage and preservation of Newhall navel oranges.

[0052] Here are the steps:

[0053] 1. Solution preparation: Weigh 0.25 g of clofopyralid 2-ethylhexyl ester, clofopyralid solid powder and 2,4-D solid powder respectively, and weigh 5% anhydrous ethanol for dissolution, and add them into 10 liters of tap water to prepare 25 mg / L clofopyralid 2-ethylhexyl ester solution, clofopyralid solution and 2,4-D solution, and select tap water as the control treatment.

[0054] 2. Experimental treatment: Select healthy Newhall navel orange fruits of uniform size and color, and soak them in the three solutions and tap water for 2 minutes. After natural drying, bag the fruits and store them at room temperature for 3 months.

[0055] 3. The experimental results are as follows:

[0056] Figure 3 The appearance of Newhall navel orange fruit treated with isooctyl fluroxypyraclostrobin, isooctyl fluroxypyraclostrobin, and 2,4-D is shown. Figure 4 Shows the appearance of Newhall navel orange pedicles treated with isooctyl fluroxypyraclostrobin, isooctyl fluroxypyraclostrobin, and 2,4-D. Figure 5 Shown is the decay rate of Newhall fruit during postharvest storage. Figure 6 The senescence rate of Newhall fruit pedicles during postharvest storage is shown. Treatment abbreviations and codes: CK: clean water; 2,4-D: 2,4-D butyl; STL: fluroxypyr; YXZ: isooctyl fluroxypyr.

[0057] from Figure 5 and Figure 6 It can be seen that after 90 days of storage, the fruit rot rate of Newhall navel oranges treated with 2,4-D was 7.3%, which was not significantly different from the 5.1% treated with 2,4-D and 5.7% treated with 2,4-D. The fruit stalk senescence rate was 7.7%, which was not significantly different from the 5.4% treated with 2,4-D and 6.6% treated with 2,4-D. Both rates were significantly lower than the 60.2% treated with clean water. Figure 3It can be seen that the citrus fruits treated with clofopyralid could not smoothly change from orange-yellow to orange-red, while the fruits treated with isooctyl clofopyralid changed color smoothly, and the color difference value of the fruits was not significantly different from that of CK and 2,4-D treatments. In addition, the experiment measured that the titratable acid of Newhall navel oranges treated with isooctyl clofopyralid, clofopyralid and 2,4-D solutions was 0.57%, 0.52% and 0.52% respectively after storage for 3 months, and the soluble solids were 11.3, 11.6 and 11.3 respectively, with no significant difference between the treatments, indicating that the preservation effect of isooctyl clofopyralid on the appearance and internal quality of Newhall navel orange fruits is equivalent to that of clofopyralid and 2,4-D.

[0058] Example 3: Application of clofopyralid 2-ethylhexyl ester in postharvest storage and preservation of ponkan oranges.

[0059] Select healthy ponkan fruits of uniform size and color, and prepare the other steps and solutions as in Example 2.

[0060] The experimental results are as follows:

[0061] Figure 7 The appearance of mandarin orange fruits treated with isooctyl fluroxypyraclostrobin, fluroxypyraclostrobin and 2,4-D is shown. Figure 8 Shows the decay rate of ponkan fruit during postharvest storage. Fig. 9 The results show the senescence rate of ponkan fruit pedicles during postharvest storage.

[0062] like Fig. 9 As shown in the results, the fruit pedicle senescence rate of mandarin oranges treated with isooctyl clofopyralid was 30.6% on the 90th day of storage, which was not significantly different from 21.3% treated with isooctyl clofopyralid and 31.6% treated with 2,4-D, and was significantly lower than 53.1% treated with water. At the same time, the color difference values ​​of Newhall navel oranges treated with isooctyl clofopyralid, isooctyl clofopyralid and 2,4-D solutions were 10.9, 10.4 and 10.3, respectively, the titratable acid was 0.37%, 0.42% and 0.40%, respectively, and the soluble solids were 10.4, 10.6 and 10.8, respectively, with no significant difference among the treatments, indicating that the preservation effect of isooctyl clofopyralid on the appearance and internal quality of mandarin oranges was comparable to that of isooctyl clofopyralid and 2,4-D, which was consistent with the experimental results of Newhall navel oranges, indicating that the preservation effect of isooctyl clofopyralid was universal.

[0063] Example 4: Application of Isooctyl Cloflupyr in the On-Tree Preservation of Late-Autumn Navel Oranges

[0064] The experimental steps are as follows:

[0065] 1. Solution preparation: Weigh 0.50 g of clofopyralid 2-ethylhexyl ester, clofopyralid solid powder and 2,4-D solid powder respectively, and weigh 5% anhydrous ethanol to assist dissolution, and add them into 10 liters of tap water to prepare a 50 mg / L solution.

[0066] 2. Experimental treatment: 12 Lunwan fruit trees with uniform growth, basically the same fruit bearing amount and about 20 years old were selected, and three biological replicates were used for each treatment. The three prepared drug solutions were sprayed on the crowns of the fruit trees during the fruit breaking period, and the control group was sprayed with water. The spraying was carried out twice, with an interval of half a month.

[0067] The experimental results are as follows:

[0068] Fig.10 The color difference values ​​of the fruits of the Lunwan navel orange treated with tree retention are shown (explanation of treatment abbreviations and codes: CK: clean water; A: 2,4-D; B: clofopyralid; C: clofopyralid 2-ethylhexyl; D: p-chlorophenoxyacetic acid; E: 2,4-D package; F: clofopyralid package; G: 27ppm p-chlorophenoxyacetic acid package; H: 50ppm p-chlorophenoxyacetic acid package; I: 80ppm p-chlorophenoxyacetic acid package; the package in this experiment is the reagent of Sichuan Guoguang Company (300 times of Power + 1000 times of Lojia + 750 times of Myclobutanil + 750 times of Jianling).

[0069] Fig.11 The results show the peel hardness of Lunwan navel orange treated with fluroxypyraclostrobin for 120 days.

[0070] Table 1 shows the sensory evaluation of Lunwanliu tree at 150 days, where CK, 2,4-D, STL, and YXZ represent clean water, 2,4-D, clofopyralid, and 2-ethylhexyl clofopyralid, respectively.

[0071] Table 2 shows the fruit pedicel senescence rate of Lunwan navel orange with a shelf life of 15 days.

[0072] Table 1 Sensory evaluation of Lunwan tree for 150 days

[0073]

[0074] Table 2 Aging rate of Tianlun late navel orange fruit pedicles during shelf life 15

[0075]

[0076] from Fig.10It can be seen that the treatment of clofopyralid with isooctyl on the tree can delay the coloring of the fruit from the 15th day to the 155th day after treatment, which is better than 2,4-D, and there is no significant difference compared with clofopyralid. The peel hardness was measured on the 120th day after treatment, and it was found that the treatment with isooctyl on the tree can significantly increase the peel hardness compared with the treatments of CK and 2,4-D, and there is no significant difference with the treatment of clofopyralid (see Fig.11 ).

[0077] On the 140th day after treatment, the fruits of Lunwan were picked, packed and delivered to the laboratory of Huazhong Agricultural University. Without post-harvest fungicides and preservatives, they were placed at room temperature for 15 days to simulate the shelf life. A sensory evaluation experiment was conducted. 30 volunteers were called to taste the fruits and score the physiological indicators of the fruits. The full score was 4 points. The results are shown in Table 1. The results showed that compared with the control treatment (hardness score 2.96, color score 2.29), the treatment with clofopyralid 2-ethylhexyl acetate obtained higher hardness scores (3.25) and color scores (2.42), indicating that the fruits treated with clofopyralid 2-ethylhexyl acetate on the tree had better appearance quality. What is even more unexpected is that the treatment with clofopyralid 2-ethylhexyl acetate significantly improved the intrinsic quality of the fruit. The acidity score was 2.25, which was significantly lower than the 2.54 of the water treatment; the sweetness score was 2.96, which was higher than the 2.88 of the water treatment; and the odor score was 1.54, which was lower than the 1.79 of the water treatment. Therefore, the fruit treated with 2-ethylhexyl fluroxypyrazone received the highest flavor score of 3.08, while the fruit treated with water received only 2.79. The fruit treated with 2-ethylhexyl fluroxypyrazone also received a higher overall satisfaction score.

[0078] At the same time, we also counted the fruit pedicle senescence rate. The fruit pedicle senescence rate of the treatment with clofopyralid was 3.85%, and that of the treatment with clofopyralid was 2.67%, which was significantly lower than that of the 2,4-D treatment (18.13%) and the water treatment (29.17%). This indicates that spraying clofopyralid before harvest can effectively maintain the freshness of the fruit pedicle after harvest.

[0079] Example 5: Application of Isooctyl Cloflupyr in the On-Tree Preservation of Sugar Mandarin Oranges

[0080] Experimental steps:

[0081] A total of 12 tangerine trees with uniform growth, basically the same fruit bearing amount and about 20 years of age were selected, and three biological replicates were performed for each treatment. Other steps and solution preparation were the same as in Example 4.

[0082] Experimental results:

[0083] Fig.12The color difference of the sugar oranges treated with tree retention is shown (explanation of treatment abbreviations and codes: CK: clean water; A: 2,4-D; B: clofopyralid; C: clofopyralid 2-ethylhexyl; D: p-chlorophenoxyacetic acid; E: 2,4-D package; F: clofopyralid package; G: 27 ppm p-chlorophenoxyacetic acid package; H: 50 ppm p-chlorophenoxyacetic acid package; I: 80 ppm p-chlorophenoxyacetic acid package).

[0084] As can be seen from the figure, the treatment of sugar oranges with isooctyl clofopyralid on the tree can delay the coloring of the fruit, and the effect is better than 2,4-D, and there is no significant difference compared with clofopyralid.

[0085] The above experiment shows that the use of the present invention to treat citrus fruits with low post-harvest maturity can significantly reduce the symptoms of delayed fruit color change caused by clofopyralid treatment. At the same time, there is no significant difference in the senescence rate and fruit rot rate of the citrus fruit pedicles after treatment compared with those treated with 2,4-D and clofopyralid, and both are significantly lower than those treated with clean water, indicating that the present invention can reduce the fruit rot rate, significantly delay the senescence of citrus fruit pedicles, and extend the storage period of the fruit. There is no significant difference in the hardness, titratable acid and soluble solids of the citrus fruits treated with the present invention compared with those treated with 2,4-D, clofopyralid or clean water, indicating that the present invention has no adverse effect on the intrinsic quality of the fruit after treating the citrus fruits.

[0086] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for treating citrus fruits, the method comprising: The fruit is immersed in a solution containing isooctyl clofopyralid, or the fruit is sprayed with a solution containing isooctyl clofopyralid; the treatment is a tree-keeping treatment or a post-harvest treatment; the concentration of isooctyl clofopyralid in the solution is 1 mg / L-500 mg / L; If the treatment is a tree-keeping treatment, the method comprises: spraying the solution on the crown of the citrus fruit tree during the color breaking period of the citrus fruit; If the treatment is post-harvest treatment, the method comprises: soaking the fruit in the solution.

2. The method according to claim 1, wherein: The solution containing isooctyl fluroxypyr is an aqueous solution.

3. The method according to claim 2, wherein: The solution comprises isooctyl fluroxypyr, water and a co-solvent.

4. The method according to claim 3, wherein: The cosolvent is ethanol.

5. The method according to any one of claims 1 to 4, wherein the concentration of isooctyl fluazifop-ethyl in the solution is 25 mg / L-50 mg / L.

6. The method according to any one of claims 1 to 4, wherein the treatment is a tree-keeping treatment, and the treatment is sprayed twice with an interval of 14 to 16 days.

7. The method according to claim 6, wherein the treatment is a tree-keeping treatment, and the treatment is sprayed twice with an interval of 15 days.

8. The method according to any one of claims 1 to 4, wherein the treatment is post-harvest treatment and the soaking time is 1 to 3 minutes.

9. The method according to claim 8, wherein the treatment is post-harvest treatment and the soaking time is 2 minutes.

10. The method according to any one of claims 1 to 4, wherein the treatment is post-harvest treatment, and the fruits are naturally dried after soaking.

11. The method according to any one of claims 1 to 4, wherein the citrus is selected from navel orange, sugar orange, ponkan, and satsuma orange.

12. The method according to claim 11, wherein the navel orange is selected from the group consisting of London late navel orange and Newhall navel orange.

13. Use of 2-ethylhexyl clofopyralid for preserving citrus fruits or improving the quality of citrus fruits, wherein the quality is intrinsic quality or extrinsic quality, and the preservation is on-tree preservation or post-harvest preservation; the use is achieved by the method described in any one of claims 1 to 12.

14. The use according to claim 13, wherein the clofopyralid is used for one or more of the following uses: reducing fruit rot, maintaining the freshness of fruit stems, increasing the hardness of fruit peel, delaying fruit coloring, extending the fruit bearing period, extending the fruit storage period, reducing the acidity of fruits, increasing the sweetness of fruits, reducing the peculiar smell of fruits, improving the flavor of fruits, reducing the slag-forming property of fruits, and increasing the juice yield of fruits.

15. The use according to claim 14, wherein the citrus is selected from navel orange, sugar orange, ponkan, and satsuma.

16. The use according to claim 15, wherein the navel orange is selected from London late navel orange and Newhall navel orange.

17. A citrus fruit preservative, the preservative being a solution comprising isooctyl clofopyralid, water and an optional cosolvent; In the solution, the concentration of isooctyl fluroxypyr is 1 mg / L-500 mg / L.

18. The citrus fruit preservative according to claim 17, wherein: The cosolvent is ethanol.

19. The citrus fruit preservative according to claim 17 or 18, wherein the concentration of 2-ethylhexyl fluazifop-butyl in the solution is 25 mg / L-50 mg / L.

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