Method for improving the degree of yellow heart of chinese cabbage by exogenous application of asparagine and application thereof

Abstract

The application discloses a method for improving the yellow heart degree of Chinese cabbage by externally applying asparagine and application thereof, and solves the technical problem of improving the carotenoid content of Brassica plants and the yellow heart degree of Brassica plants, and specifically discloses the use of asparagine or a salt thereof or a solvate thereof in improving the carotenoid content of Brassica plants and the yellow heart degree of Brassica plants, wherein the above-mentioned substance is used in Brassica plants to improve the carotenoid content and increase the yellow heart degree, and can be used in agricultural production.

Description

Technical Field

[0001] This invention relates to the field of molecular biology, and in particular to a method for improving the yellowing of Chinese cabbage by exogenously applying asparagine and its application. Background Technology

[0002] Chinese cabbage (Brassica rapa L.ssp.pekinensis) originated in my country, with an annual planting area of ​​approximately 27 million mu (1.8 million hectares), making it one of the most widely cultivated major vegetable crops in the country and playing a vital role in year-round vegetable supply and emergency security. Yellow-hearted Chinese cabbage, due to its bright yellow inner leaves, good marketability, high lutein content, and rich nutrition, is increasingly in demand. Although yellow-hearted Chinese cabbage has existed in my country since ancient times, the market did not have a particular demand for the degree of yellowing in the cabbage at that time, so this trait did not receive sufficient attention. In recent years, Japan and South Korea, driven by the high demand for yellow-hearted cabbage in kimchi processing, have improved the yellowing of the inner leaves, quality, and bolt resistance of Chinese cabbage, capturing the majority of the market share. Therefore, cultivating fresh yellow-hearted, high-quality Chinese cabbage is urgently needed. How to improve the degree of yellowing in Chinese cabbage is a technical problem faced by researchers in this field. Summary of the Invention

[0003] The technical problem solved by this invention is to improve the yellowing of the heart and the content of carotenoids in Brassica plants. Applying the above-mentioned substances to Brassica plants can increase the content of carotenoids and increase the yellowing of the heart.

[0004] In a first aspect, the present invention provides a method for increasing the yellowing of the heart and the content of carotenoids in Brassica plants, the method comprising the step of applying asparagine or a salt thereof, or a product containing asparagine or a salt thereof, to the Brassica plants during cultivation.

[0005] In another aspect, the present invention provides a method for cultivating Brassica plants, the method comprising the step of applying asparagine or a salt thereof, or a product containing asparagine or a salt thereof, to the Brassica plants.

[0006] In some embodiments, the product includes a composition, a core-forming agent, and / or a plant growth promoter.

[0007] In some embodiments, the application is characterized by occurring between the rosette stage and the heading stage.

[0008] In some embodiments, the amount of asparagine applied is 100-300 mg per Brassica plant.

[0009] In some embodiments, the amount applied is 200 mg per Brassica plant.

[0010] In some embodiments, the concentration of asparagine applied is 20-60 mg / mL.

[0011] In some embodiments, the concentration of the substance being applied is 40 mg / mL.

[0012] In some embodiments, the asparagine is applied twice a week.

[0013] In another aspect, the present invention provides compositions comprising asparagine or its salts, or solvates thereof, or any combination thereof.

[0014] In some embodiments, the composition is a fruiting agent or a plant growth promoter.

[0015] In some implementations, the application time is 17:00-18:00.

[0016] In some implementations, the application time is 17:01, 17:02, 17:03, 17:04, 17:05, 17:06, 17:07, 17:08, 17:09, 17:10, 17:11, 17:12, 17:13, 17:14, 17:15, 17:16, 17:17, 17:18, 17:19, 17:20, 17:21, 17:22, 17:23, 17:24, 17:25, 17:26, 17:27, 17:28, 17: 29, 17:30, 17:31, 17:32, 17:33, 17:34, 17:35, 17:36, 17:37, 17:38, 17:39, 17:40, 17:41, 17:42, 17:43, 17:44, 17:45, 17:46, 17:47, 17:48, 17:49, 17:50, 17:51, 17:52, 17:53, 17:54, 17:55, 17:56, 17:57, 17:58, 17:59, 18:00.

[0017] Use of asparagine or its salts, or their solvates, in increasing the carotenoid content and / or the yellowing of the heart of Brassica plants.

[0018] In another aspect, the present invention provides compositions comprising asparagine or a salt thereof, or a solvate thereof, or any combination thereof;

[0019] In some embodiments, the composition is used to improve agricultural traits of plants.

[0020] In some implementations, the improvement of agricultural traits includes increasing the degree of yellowing of the heart.

[0021] In some embodiments, the composition is used on plants from the rosette stage to the heading stage.

[0022] In some embodiments, the composition is formulated as a solid or liquid dosage form.

[0023] In some embodiments, the composition further includes excipients and / or additives.

[0024] In some embodiments, the excipients include agriculturally or horticulturally acceptable diluents, fillers, solvents, spontaneous accelerators, carriers, emulsifiers, dispersants, thickeners, binders, or any combination thereof.

[0025] In some embodiments, the additive includes agriculturally or horticulturally acceptable preservatives, adjuvants, synergists, microbial additives, antifreeze agents, or any combination thereof.

[0026] In some embodiments, the composition is a liquid formulation.

[0027] In some embodiments, the liquid formulation includes emulsifiable concentrates, soluble concentrates, oils, dispersible liquids, electrostatic spray liquids, suspensions, microcapsule suspensions, oil suspensions, suspension emulsions, water emulsions, microemulsions, nanoemulsions, or any combination thereof.

[0028] In some embodiments, the asparagine is in an agriculturally or fertilizer-acceptable carrier in the liquid formulation.

[0029] In some embodiments, the asparagine content in the liquid formulation is 20-60 mg / mL.

[0030] In some embodiments, the asparagine content in the liquid formulation is 40 mg / mL.

[0031] In some embodiments, the liquid formulation is used for root soaking, foliar spraying, spraying, composting, seed soaking, coating, flood irrigation, drip irrigation of plants or plant organs, application to plants or plant organs, or drip application to plants or plant organs, or any combination thereof.

[0032] In some embodiments, the composition is a solid dosage form.

[0033] In some embodiments, the asparagine in the solid formulation is contained in an agriculturally or fertilizer-acceptable carrier.

[0034] In some embodiments, the solid preparation may be used for composting, applying to plants or plant organs, or any combination thereof.

[0035] In some embodiments, the solid dosage form is used to formulate the liquid dosage form described above.

[0036] In some embodiments, the solid or liquid formulation is selected from foliar treatment formulations, soil treatment formulations, seed treatment formulations, stem treatment formulations, root treatment formulations, or any combination thereof.

[0037] In some embodiments, the plant is a plant in the rosette stage to the heading stage.

[0038] In another aspect, the present invention provides a core-filling agent comprising any of the compositions described above.

[0039] In another aspect, the present invention provides plant growth promoters comprising any of the compositions described above.

[0040] In another aspect, the present invention provides a method for cultivating Brassica plants, the method comprising the steps of applying asparagine or its salt, any of the compositions described above, the above-described pericarp agent, and the above-described plant growth promoter to Brassica plant tissues and / or organs.

[0041] In some embodiments, the application includes one or more of the following: root soaking, foliar spraying, spraying, composting, seed soaking, coating, flood irrigation, drip irrigation of plants or plant organs, smearing of plants or plant organs, and drip application of plants or plant organs.

[0042] In some implementations, the application is performed from the rosette stage to the bulb stage.

[0043] In some embodiments, the concentration of asparagine used in the foliar spray is 20-60 mg / mL.

[0044] In some embodiments, the concentration of asparagine used in the foliar spray is 40 mg / mL.

[0045] In some embodiments, the amount of foliar spraying is 5 mL per plant.

[0046] In some embodiments, the foliar spraying is performed twice a week.

[0047] In some embodiments, the method is used to obtain Brassica plants with high carotenoid content.

[0048] In some embodiments, the carotenoid content of the Brassica plants with high carotenoid content is higher than that of Brassica plants obtained without the application of the composition, the foraminifera, and the plant growth promoter.

[0049] In some embodiments, the method is used to obtain Brassica plants with a high degree of yellowing of the heart.

[0050] In some embodiments, the degree of yellowing of the Brassica plants with high yellowing is higher than that of Brassica plants obtained without application of the composition, the core-forming agent, or the plant growth promoter.

[0051] In some implementations, the degree of yellowness refers to the area or volume percentage of the yellow region.

[0052] In some implementations, the high yellow heart level refers to the high yellow heart level during the heading stage.

[0053] In some embodiments, the carotenoid content is the high carotenoid content during the heading stage.

[0054] In another aspect, the present invention provides a method for improving the yellow heart of Brassica plants, comprising, during the cultivation of Brassica plants, applying asparagine or a salt thereof, any of the above-described compositions, the above-described core-forming agents, or the above-described plant growth promoters to the Brassica plants.

[0055] In some embodiments, the Brassica species includes Brassica tissues and / or organs.

[0056] In some embodiments, the *Caragana* plant tissues and / or organs include roots, stems, leaves, flowers, fruits, seeds, or any combination thereof.

[0057] In some embodiments, the application includes one or more of the following: root soaking, foliar spraying, spraying, composting, seed soaking, coating, flood irrigation, drip irrigation of plants or plant organs, smearing of plants or plant organs, and drip application of plants or plant organs.

[0058] In some implementations, the application is performed from the rosette stage to the bulb stage.

[0059] In some embodiments, the concentration of asparagine used in the foliar spray is 20-60 mg / mL.

[0060] In some embodiments, the concentration of asparagine used in the foliar spray is 40 mg / mL.

[0061] In some embodiments, the amount of foliar spraying is 5 mL per plant.

[0062] In some embodiments, the foliar spraying is performed twice a week.

[0063] In some embodiments, the method is used to obtain Brassica plants with high carotenoid content.

[0064] In some embodiments, the carotenoid content of the Brassica plants with high carotenoid content is higher than that of Brassica plants obtained without the application of the composition, the foraminifera, and the plant growth promoter.

[0065] In some embodiments, the method is used to obtain Brassica plants with a high degree of yellowing of the heart.

[0066] In some embodiments, the degree of yellowing of the Brassica plants with high yellowing is higher than that of Brassica plants obtained without the application of the composition, the core-forming agent, and the plant growth promoter.

[0067] In some implementations, the degree of yellowness refers to the area or volume percentage of the yellow region.

[0068] In some implementations, the high yellow heart level refers to the high yellow heart level during the heading stage.

[0069] In some embodiments, the carotenoid content is the high carotenoid content during the heading stage.

[0070] In another aspect, the present invention provides the use of any of the compositions described above, the above-described core-forming agents, and the above-described plant growth promoters in increasing the carotenoid content of Brassica plants and increasing the degree of yellowing of the core in Brassica plants.

[0071] In some implementations, the degree of yellowness refers to the area or volume percentage of the yellow region.

[0072] In some embodiments, the plant is a plant leaf.

[0073] In some embodiments, the asparagine is L-asparagine.

[0074] In some embodiments, the Brassica species are selected from Chinese cabbage, bok choy, Chinese cabbage hearts, or any combination thereof, as described in any of the above-described compositions, the above-described foramen-forming agents, the above-described methods, or the above-described uses.

[0075] In some implementation schemes, the Chinese cabbage is selected from Tianjin Qingmaye, Yutian Baojian Chinese cabbage, Jincai No. 3, Jiaozhou Chinese cabbage, Fushan Baotou, Beijing Xin No. 3, Taiyuan Erbaotou, Luoyang Dabaotou, Beijing Xiaoza No. 56, Lubai No. 6, Chun Dajiang, Jinguan, Ziyi, or any combination thereof.

[0076] In some implementations, the bok choy is selected from Shanghai bok choy, Suzhou bok choy, dwarf yellow bok choy, arrow-shaped white bok choy, Hangzhou oil-fleshed bok choy, horse-ear bok choy, or any combination thereof.

[0077] In some embodiments, the choy sum is selected from varieties such as Sijiu choy sum, Youqing sweet choy sum, Liuye early choy sum, Qingliuye choy sum, Huangye center choy sum, Chixin No. 2, Sanyueqing, Hongfu No. 1, Yueyou No. 1, or any combination thereof. In another aspect, the present invention provides the use of asparagine or its salts, or their solvates, in increasing the carotenoid content and the degree of yellowing of the heart in Brassica plants.

[0078] In some implementations, the degree of yellowness refers to the area or volume percentage of the yellow region.

[0079] In some embodiments, the plant is a plant leaf.

[0080] In some embodiments, the asparagine is L-asparagine.

[0081] In some embodiments, the Brassica species are selected from Chinese cabbage, bok choy, Chinese cabbage hearts, or any combination thereof.

[0082] In some implementations, the Chinese cabbage is Beijing New No. 3.

[0083] In some embodiments, the use is for preparing related products. The products are compositions.

[0084] In some embodiments, the composition further includes one or more chemical agents.

[0085] In some embodiments, the composition further comprises agriculturally or horticulturally acceptable diluents, fillers, solvents, spontaneous promoters, carriers, emulsifiers, preservatives, dispersants, antifreeze agents, thickeners, adjuvants, synergists, microbial additives, binders, plant growth regulators, or any combination thereof.

[0086] In some embodiments, the dispersant and / or emulsifier includes all nonionic, anionic, or cationic dispersants conventionally used in formulations of active agricultural chemicals.

[0087] In some embodiments, examples of the preservatives include, but are not limited to, dichlorophenol and benzyl alcohol hemiacetal.

[0088] In some embodiments, examples of the adhesive include, but are not limited to, starch, polyvinyl alcohol, and gelatin.

[0089] In some embodiments, examples of the dispersant include, but are not limited to, sodium dodecylbenzenesulfonate and sodium butylnaphthalenesulfonate.

[0090] In some embodiments, examples of the stabilizer include, but are not limited to, silica, talc, and dicyandiamide.

[0091] In some implementations, examples of the synergist include, but are not limited to, sodium nitrophenolate and vitamin C.

[0092] In some embodiments, examples of the filler include, but are not limited to, volcanic rock powder and ammonium bicarbonate.

[0093] In some embodiments, examples of the plant growth regulator include, but are not limited to, 28-homobrassinolide, brassinolide, and natural pigments (such as β-carotene).

[0094] In some implementations, examples of agriculturally or horticulturally acceptable diluents include aqueous solutions of monosaccharides, polysaccharides, molasses, gums, lignin sulfonates, glycerol, sorbitol, propylene glycol, water, vegetable oils, and mineral oils.

[0095] In some embodiments, the carrier may include alginate beads, durum wheat flour particles, silica, clay, clay minerals, gelatin, cellulose, cellulose derivatives, calcium chlorite, solid talc, diatomaceous earth, activated carbon, animal bone charcoal, peat, vermiculite, lignite, sawdust, and / or corn cobs.

[0096] In some embodiments, the chemical agent is selected from herbicides, insecticides, antibacterial agents, antiviral agents, plant growth regulators, antibiotics, fertilizers, or any combination thereof.

[0097] In some embodiments, the antimicrobial agent is selected from cymoxanil hydrochloride, carbendazim, fluazinam, chlorothalonil, pentachloronitrobenzene, thiram, aluminum triethylphosphonate, metalaxyl, metalaxyl-fludioxonil, or any combination thereof.

[0098] Preferably, the insecticide is selected from thiamethoxam, fipronil, lambda-cyhalothrin, propoxur, or any combination thereof.

[0099] In some embodiments, the fertilizer is selected from urea, ammonium sulfate, Huanzhitian, Antangkeli, potassium dihydrogen phosphate, or any combination thereof.

[0100] In some implementations, the use of asparagine foliar spraying produces the aforementioned effects. Asparagine enters the plant and exerts its effects, and asparagine can be transported to plant leaves or other plant organs through the xylem. Therefore, those skilled in the art can conclude that the corresponding technical effects can be achieved by choosing to apply asparagine through root soaking, foliar spraying, spraying, composting, seed soaking, coating, flood irrigation, drip irrigation of plants or plant organs, application to plants or plant organs, or drip addition to plants or plant organs.

[0101] In some embodiments, the composition is a liquid fertilizer.

[0102] In some embodiments, the asparagine is in a fertilizer-acceptable carrier in the composition.

[0103] In some embodiments, the liquid fertilizer is a clear liquid fertilizer or a suspension fertilizer.

[0104] In some embodiments, the asparagine content in the liquid fertilizer is 20-60 mg / mL. In some embodiments, the asparagine content is 21-59 mg / mL, 22-58 mg / mL, 23-57 mg / mL, 24-66 mg / mL, 25-55 mg / mL, 26-54 mg / mL, 27-53 mg / mL, 28-52 mg / mL, 29-51 mg / mL, 30-50 mg / mL, 31-49 mg / mL, 32-48 mg / mL, 33-47 mg / mL, 34-46 mg / mL, 35-45 mg / mL, 36-44 mg / mL, 37-43 mg / mL, 38-42 mg / mL, 39-41 mg / mL, or 40 mg / mL.

[0105] In some embodiments, the asparagine content is 40 mg / mL.

[0106] In some embodiments, the composition is used for one or more of the following: root soaking, foliar spraying, spraying, composting, seed soaking, coating, flood irrigation, drip irrigation of plants or plant organs, application to plants or plant organs, and drip application to plants or plant organs.

[0107] In some implementations, the above operation is performed from the rosette stage to the bulb stage.

[0108] In some implementations, the above operation is performed at 5 mL per plant.

[0109] In some embodiments, the foliar spray is L-asparagine.

[0110] In some embodiments, the composition is a solid fertilizer or a powdered fertilizer.

[0111] In some embodiments, the asparagine is in a fertilizer-acceptable carrier in the composition.

[0112] In some embodiments, the composition is used for composting, applying to plants or plant organs, or any combination thereof.

[0113] In some embodiments, the powdered fertilizer is used to formulate the liquid fertilizer described above.

[0114] In some embodiments, the composition is a powdered fertilizer. The powdered fertilizer is used to formulate the above-described liquid fertilizer or the above-described solid fertilizer.

[0115] In another aspect, the present invention provides a core-forming agent comprising the above-described composition, the above-described liquid fertilizer, the above-described solid fertilizer, or the above-described powdered fertilizer.

[0116] In another aspect, the present invention provides a plant growth promoter comprising the above-described composition, the above-described liquid fertilizer, the above-described solid fertilizer, or the above-described powdered fertilizer.

[0117] In another aspect, the present invention provides a method for cultivating Chinese cabbage, comprising any of the following:

[0118] (1) The method includes applying the above composition, the above liquid fertilizer, the above solid fertilizer, the above head-forming agent and / or the above plant growth promoter to Chinese cabbage tissues and / or organs to obtain Chinese cabbage with high carotenoid content, wherein the carotenoid content of the Chinese cabbage with high carotenoid content is higher than that of Chinese cabbage obtained without the application of the above or the aforementioned products.

[0119] (2) The method includes the step of applying the above composition, the above liquid fertilizer, the above solid fertilizer, the above head-forming agent and / or the above plant growth promoter to Chinese cabbage tissues and / or organs to obtain Chinese cabbage with a high degree of yellow heart, wherein the degree of yellow heart of the Chinese cabbage with a high degree of yellow heart is higher than that of Chinese cabbage obtained without the application of the above or the aforementioned products.

[0120] In some implementations, the degree of yellowness refers to the area or volume percentage of the yellow region.

[0121] In some embodiments, the application includes one or more of the following: root soaking, foliar spraying, spraying, composting, seed soaking, coating, flood irrigation, drip irrigation of plants or plant organs, smearing of plants or plant organs, and drip application of plants or plant organs.

[0122] In some implementations, the foliar spray is applied at 5 mL per plant, twice a week.

[0123] In some implementations, the foliar spray is applied at 5 mL per plant, once every 3.5 days.

[0124] In some implementations, the application is performed from the rosette stage to the bulb stage.

[0125] In some implementations, the high yellow heart level refers to the high yellow heart level during the heading stage.

[0126] In some embodiments, the carotenoid content is the high carotenoid content during the heading stage.

[0127] Beneficial effects

[0128] L-Asparagine (L-Asn) is one of the most common amino acids in living organisms and has a wide range of applications in various fields. In the pharmaceutical field, it can be used to treat heart disease, liver disease, hypertension, and to relieve fatigue; in the industrial field, it can be used as a food additive to improve the nutritional value and taste of food; in the agricultural field, it can be used as a plant growth regulator to promote plant growth and development and improve crop quality.

[0129] This invention discloses a method for increasing the yellow heart of Chinese cabbage by exogenously applying asparagine and its application. The technical problem solved is to increase the carotenoid content and yellow heart of Brassica plants. Specifically, it discloses the use of asparagine or its salts, or their solvates, in increasing the carotenoid content and yellow heart of Brassica plants. Applying the above substances to Brassica plants can increase the carotenoid content and increase the yellow heart, which can be used in agricultural production. Attached Figure Description

[0130] Figure 1 The yellow-heart phenotype of Chinese cabbage in different treatment groups provided in Embodiment 1 of the present invention.

[0131] Figure 2 The total carotenoid content of the heart leaves of Chinese cabbage in different treatment groups provided in Example 1 of the present invention. Detailed Implementation

[0132] The present invention will now be described in further detail with reference to specific embodiments. The given embodiments are merely illustrative of the invention and not intended to limit its scope. The embodiments provided below can serve as a guide for further improvements by those skilled in the art and do not constitute a limitation on the invention in any way.

[0133] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Unless otherwise specified, the materials and reagents used in the following examples are commercially available.

[0134] The data in the following examples were processed using SPSS 11.5 statistical software. The experimental results are expressed as mean ± standard deviation. One-way ANOVA was used, and P < 0.05 (*) indicates a significant difference, and P < 0.01 (**) indicates a highly significant difference.

[0135] In this invention, unless otherwise stated, the scientific and technical terms used herein have the meanings commonly understood by those skilled in the art. Furthermore, the terms and laboratory procedures related to protein and nucleic acid chemistry, molecular biology, cell and tissue culture, microbiology, and immunology used herein are all widely used terms and routine procedures in their respective fields. To better understand this invention, definitions and explanations of relevant terms are provided below.

[0136] As used in this article, the term "Trp" refers to tryptophan, also known as β-indoleylalanine, an organic compound with the chemical formula C. 11 H 12 N2O2. Specifically, in this example, it refers to L-tryptophan (L-Trp), whose structural formula is as follows:

[0137]

[0138] As used herein, the term "Asn" refers to aspartic acid, an organic compound with the chemical formula C4H7NO4. In the examples, it specifically refers to L-aspartic acid (L-Asn), whose structural formula is as follows:

[0139]

[0140] As used in this article, the terms “comprising,” “including,” “having,” “containing,” etc., are all open-ended terms, meaning that they include but are not limited to.

[0141] As used herein, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0142] As used herein, the terms “optionally,” “optionally,” or “optionally” generally mean that an event or condition described below may, but may not, occur, and the description includes both cases in which the event or condition occurs and cases in which the event or condition does not occur.

[0143] As used in this article, the term "roselet stage" refers to the transitional phase from the end of the seedling stage to the beginning of the heading stage. Specifically, it refers to the period from when the Chinese cabbage has grown eight true leaves to the beginning of the heading stage.

[0144] As used in this article, the term "heading stage" refers to the stage in Chinese cabbage from when the outer leaves (roselet leaves) stop growing and the inner leaves begin to curl inward to form a head.

[0145] As used in this article, the term "yellowing degree" refers to the degree to which the leaves inside the head turn yellow, and is commonly used to assess the quality of leafy vegetables such as Chinese cabbage and kale.

[0146] Example 1: Exogenous application of L-asparagine (L-Asn) scheme

[0147] The experimental material was Chinese cabbage, Beijing New No. 3, which came from the Vegetable Research Institute of Beijing Academy of Agricultural and Forestry Sciences. It was sown and planted at the Sijiqing Farm of the Vegetable Research Institute of Beijing Academy of Agricultural and Forestry Sciences and was cultivated and managed in a conventional manner.

[0148] This experiment was divided into three groups: a control group, an L-Asn group (experimental group), and an L-Trp group (the control group was sprayed with H2O, the L-Trp group was sprayed with L-Trp, and the L-Asn group (experimental group) was sprayed with L-Asn). Each group had five replicates. We conducted a preliminary screening experiment for the optimal L-Asn spraying method, selecting the spraying times from 7:00-10:00 AM, 11:00-2:00 PM, and 4:00-7:00 PM; the spraying concentration range from 10 mg / mL to 80 mg / mL; and the spraying frequency from 1 to 7 times per week. Finally, we determined the optimal L-Asn spraying method: starting from the rosette stage, from 5:00 PM to 6:00 PM, evenly spray a 40 mg / mL L-Asn solution onto the leaves of Chinese cabbage in the form of a water mist, twice a week, continuously until the heading stage.

[0149] Example 2: Survey of agronomic traits in different treatment groups

[0150] Chinese cabbage variety Beijing New No. 3 (from the Vegetable Research Institute of Beijing Academy of Agricultural and Forestry Sciences) was sown on August 10, 2024, at the Sijiqing Farm of the Vegetable Research Institute of Beijing Academy of Agricultural and Forestry Sciences, and cultivated and managed using conventional methods. In this experiment, Beijing New No. 3 was randomly divided into three groups: a control group, an L-Asn group (experimental group), and an L-Trp group (the control group was sprayed with H2O, the L-Trp group was sprayed with L-Trp, and the L-Asn group (experimental group) was sprayed with L-Asn). Each group had five plants, and each group had three replicates. When the Chinese cabbage Beijing New No. 3 reached the rosette stage… In the experimental group, from 17:00 to 18:00, a 40 mg / mL L-Asn solution (water as solvent) was evenly sprayed onto the leaves of Chinese cabbage in the form of water mist, with 5 mL sprayed per plant. The control group was sprayed with the same amount of solvent (water) using the same method. The L-Trp group was sprayed with the same amount of 40 mg / mL L-Trp solution (water as solvent) using the same method. All groups were sprayed twice a week until the heading stage. Three plants with uniform growth were selected from each treatment group, and plant height, plant spacing, raw weight, net weight, head height, head width, and central column length were measured. It was found that compared with H2O spraying and L-Trp spraying, the plant height of L-Asn sprayed plants was significantly reduced, while other agronomic traits did not differ significantly (see Table 1 for details).

[0151] Plant height: from the soil surface to the tip of the tallest leaf.

[0152] Plant spacing: The distance between the two furthest leaves.

[0153] Wild weight: The weight of the entire plant (excluding the part below the soil surface).

[0154] Net weight: The weight of the entire head (excluding the part below the soil surface and the outer leaves).

[0155] Head height: The vertical distance from the base of the head to the tip of the head.

[0156] Ball width: The horizontal distance from one edge of the widest part of the ball to the other edge.

[0157] Central column length: The vertical length from the base to the top of the central column.

[0158] Table 1. Agronomic traits of different treatment groups

[0159]

[0160]

[0161] Example 3: Investigation of yellow heart phenotype and determination of carotenoid content in different treatment groups

[0162] The yellow-heart trait and carotenoid content of the Chinese cabbage variety Beijing New No. 3, taken from Example 2 up to the heading stage, were investigated, as follows:

[0163] Three plants with uniform growth were selected from each treatment group (control group, L-Asn group and L-Trp group) and named H2O-1, H2O-2, H2O-3, L-Asn-1, L-Asn-2, L-Asn-3, L-Trp-1, L-Trp-2 and L-Trp-3 respectively. The yellow heart trait and carotenoid content were investigated.

[0164] The results showed that, compared with H2O and L-Trp, L-Asn significantly increased the degree of yellowing of the plant heart. Figure 1 , Figure 1 In this study, H2O (H2O-1, H2O-2, and H2O-3) served as the control group, L-Asn (L-Asn-1, L-Asn-2, and L-Asn-3) served as the L-Asn group, and L-Trp (L-Trp-1, L-Trp-2, and L-Trp-3) served as the L-Trp group.

[0165] Then, 0.2g of the innermost 5cm of the leaf head from the same part of the leaf group was selected from different treatment groups, cut into small pieces, and placed in 10mL of 80% acetone solution. The solution was soaked at room temperature in the dark for 24 hours. The absorbance of the extract at 470nm was then measured using a DU800 UV spectrophotometer, with three biological replicates for each sample. The carotenoid content was calculated according to Arnon's (1949) method: Carotenoid: Car=(1000×OD470×V / W-3.27×Chl a-104×Chl b) / 198; where OD470 is the absorbance value on the DU800 UV spectrophotometer; V: total volume of extract (mL); W: fresh weight of leaf (g). The results showed that, compared with H2O spraying, L-Trp spraying did not significantly change the carotenoid content of the plants; however, compared with H2O and L-Trp spraying, L-Asn spraying significantly increased the carotenoid content of the plants. Figure 2 , Figure 2 In the study, H2O served as the control group, L-Asn as the L-Asn group, and L-Trp as the L-Trp group.

[0166] In summary, this invention provides a method for improving the yellow heart of Chinese cabbage by exogenously applying L-Asn. This method can easily, safely, economically, and efficiently increase the yellow heart and carotenoid content of Chinese cabbage heads. It can be applied to the breeding of Chinese cabbage head quality and is of great significance for the study of the molecular mechanism of yellow heart formation.

[0167] The present invention has been described in detail above. For those skilled in the art, the invention can be practiced in a wide range of ways with equivalent parameters, concentrations, and conditions without departing from its spirit and scope, and without requiring unnecessary experiments. Although specific embodiments have been given, it should be understood that further modifications can be made to the invention. In summary, according to the principles of the invention, this application is intended to include any changes, uses, or improvements to the invention, including changes made using conventional techniques known in the art that depart from the scope disclosed herein. Some of the essential features can be applied within the scope of the following appended claims.

Claims

1. A method for increasing the yellowing of the heart and / or the content of carotenoids in Brassica plants, characterized in that, The method includes the step of applying asparagine or a salt thereof, or a product containing asparagine or a salt thereof, to Brassica plants during cultivation. The application is foliar spraying; The application time is from the rosette stage to the heading stage; The application time is 17:00-18:00; The concentration of asparagine applied was 40 mg / mL; The asparagine is applied twice a week. The Brassica species mentioned are Chinese cabbage, bok choy, Chinese cabbage hearts, or any combination thereof.

2. A method for cultivating Brassica plants, characterized in that, The method includes the step of applying asparagine or its salt, or a product containing asparagine or its salt, to Brassica plants to obtain Brassica plants with high carotenoid content; The application is foliar spraying; The application time is from the rosette stage to the heading stage; The application time is 17:00-18:00; The concentration of asparagine applied was 40 mg / mL; The asparagine is applied twice a week. The Brassica species mentioned are Chinese cabbage, bok choy, Chinese cabbage hearts, or any combination thereof.

3. The method as described in claim 1 or 2, characterized in that, The amount of asparagine applied is 100-300 mg per Brassica plant.

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