A method for increasing the content of malonic acid in cucumbers

Abstract

The present invention belongs to the technical field of vegetable cultivation, and specifically provides a method for increasing the content of malonic acid in cucumbers. During the growth period of cucumber plants, an exogenous preparation is sprayed to increase the content of malonic acid in the cucumbers; the exogenous preparation is a sucrose aqueous solution or a carbon treasure aqueous solution. By reasonably spraying low concentrations of sucrose and carbon treasure, the present invention greatly increases the content of malonic acid in cucumber fruits, providing technical support for the screening of functional cucumber varieties with high malonic acid content; moreover, the application method of the present invention is simple to operate, low in cost, and high in efficiency. In addition, the exogenous preparation applied in the present invention can improve the absorption of nutrients by crops and at the same time reduce the risk of environmental pollution.

Description

Technical Field

[0001] The present invention relates to the technical field of vegetable cultivation, and relates to a method for cultivating cucumbers, and particularly relates to a method for increasing the content of malic acid in cucumbers. Background Art

[0002] Cucumber (cucumis sativus L.), also known as cucumber and green cucumber, is one of the top ten important vegetable crops in the world. Cucumbers are rich in nutrients. In addition to containing protein, fat, glucose, fructose, carotene, vitamins, etc., they also contain cellulose and various small molecule organic acids, such as malic acid. Malic acid is a type of dicarboxylic acid with the structural formula HOOCCH(OH)COOH, and its full name is hydroxy malonic acid. It is easily soluble in water and alcohol, and the anhydrous form can be dissolved in ether, while the form containing crystal water is hardly soluble in ether. Malic acid can undergo catalytic oxidation with air to form pyruvic acid, which is used in organic synthesis. Malic acid can also inhibit the conversion of carbohydrates into fat and prevent the accumulation of fat in the body, but it does not prevent carbohydrates from providing heat and energy (Iakusheva, 1958). However, the human body cannot synthesize malic acid by itself and must obtain it from food. Cucumber is one of the only several plant sources of organic malic acid.

[0003] The inheritance of fruit organic acid content is relatively complex: one is a qualitative trait with high acidity being dominant over low acidity and being controlled by 1 pair of alleles; the other is a quantitative trait with continuous variation in the content of each component acid in the hybrid offspring, which is controlled by multiple genes and conforms to quantitative trait inheritance. The content of malic acid in cucumber fruits is a quantitative trait controlled by multiple genes. The results of genetic variance analysis show that it conforms to the additive-dominant (AD) genetic model of genotype and environment interaction. The content of malic acid in cucumbers is mainly affected by additive and additive-environment interaction effects and is greatly affected by the environment. In the prior art, methods such as applying organic acids or nitrogen fertilizers are often used to increase the content of malic acid in crops. However, organic acids or nitrogen fertilizers are generally added to the soil or hydroponic nutrient solution, resulting in a relatively high usage amount of organic acids or nitrogen fertilizers and a cumbersome application method.

[0004] Therefore, it is of great significance to study a method for increasing the content of malic acid in cucumber fruits that is simple to operate and low in cost. Summary of the Invention

[0005] The present invention provides a method for increasing the content of malic acid in cucumbers to solve the defect of low content of malic acid in cucumbers in the prior art, and to achieve a method for cultivating cucumbers that is simple to operate, low in cost and high in efficiency.

[0006] The present invention provides a method for increasing the content of malic acid in cucumbers. During the growth period of cucumber plants, an exogenous preparation is sprayed to increase the content of malic acid in the cucumbers;

[0007] The exogenous preparation described above is an aqueous sucrose solution or an aqueous solution of Carbon Treasure;

[0008] The spraying described above is foliar spraying.

[0009] In view of the problems of cumbersome operation and large usage amount existing in organic acids or nitrogen fertilizers in the prior art, the present invention unexpectedly finds that by adopting the method of foliar spraying a low-concentration aqueous sucrose solution or an aqueous solution of Carbon Treasure, the content of malonic acid in cucumbers can be significantly increased. The method of the present invention is simple to operate, the usage amounts of sucrose and Carbon Treasure are small, and sucrose and Carbon Treasure are environmentally friendly and low in cost, which is a very important cucumber planting method.

[0010] According to a method for increasing the content of malonic acid in cucumbers provided by the present invention, the aqueous sucrose solution is composed of sucrose and water; the mass fraction of the aqueous sucrose solution is 0.50%.

[0011] According to a method for increasing the content of malonic acid in cucumbers provided by the present invention, the aqueous solution of Carbon Treasure is composed of Carbon Treasure and water; wherein, the volume ratio of Carbon Treasure to water in the aqueous solution of Carbon Treasure is 1:300.

[0012] According to a method for increasing the content of malonic acid in cucumbers provided by the present invention, the Carbon Treasure includes Bacillus subtilis and Bacillus amyloliquefaciens.

[0013] According to a method for increasing the content of malonic acid in cucumbers provided by the present invention, in the Carbon Treasure, amino acids ≥ 2%, organic matter ≥ 10%, and effective viable strains ≥ 200 million / mL.

[0014] According to a method for increasing the content of malonic acid in cucumbers provided by the present invention, the spraying described above is foliar spraying. The present invention adopts foliar spraying to quickly supplement nutrients. Foliar spraying is not restricted by soil factors and has a high nutrient utilization rate; it is economical and safe, with a small spraying amount, which is both economical and effective and saves costs. When performing foliar spraying, pay attention that the mist droplets are small, the spraying is uniform, and pay attention to spraying on the vigorously growing leaves; generally choose to spray in the afternoon on a sunny day when the sun is not strong or on a cloudy day, and generally the spraying effect is best in the evening. For example, spray from 2 to 5 pm.

[0015] According to a method for increasing the content of malonic acid in cucumbers provided by the present invention, the frequency of spraying is: spraying once every seven days, and the total number of spraying times is three times; the amount of each spraying is 1 - 3 mL / plant. The spraying amount is specifically sprayed according to the size of the plant, and it is best to have a slight dripping phenomenon.

[0016] According to a method for increasing the content of malonic acid in cucumbers provided by the present invention, the content of malonic acid in the cucumbers is 23.3 - 27.0% higher than that of the control group;

[0017] The only difference between the described control group and the cucumber is that during the growth period of the cucumber plants, the sprayed exogenous preparation is replaced with water.

[0018] A method for increasing the content of malic acid in cucumbers provided by the present invention greatly increases the content of malic acid in cucumber fruits by reasonably spraying low-concentration sucrose aqueous solution and carbon treasure aqueous solution, providing technical guarantee for the screening of functional high-malic acid cucumber varieties; moreover, the application method of the present invention is simple to operate, low in cost and high in efficiency. In addition, the exogenous preparation applied in the present invention can improve the absorption of nutrients by crops and at the same time reduce the risk of environmental pollution. Brief Description of the Drawings

[0019] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0020] Figure 1 It is the growth diagram of the plant after spraying the exogenous preparation provided by the present invention;

[0021] Figure 2 It is the standard curve of malic acid provided by the present invention;

[0022] Figure 3 It is the chromatogram of the standard solution of malic acid provided by the present invention. Detailed Embodiments

[0023] To make the objectives, technical solutions and advantages of the present invention clearer, the following will clearly and completely describe the technical solutions in the present invention with reference to the drawings in the present invention. Obviously, the described embodiments are some but not all of the embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0024] The following combines Figures 1 - 3 Describe a method for cultivating cucumbers of the present invention.

[0025] Among them, the tested variety is: Cucumber germplasm material "3667" (Changchun Mici) of China Agricultural University. The tested exogenous preparations are: citric acid (purchased from Beijing Bio-Top Technology Co., Ltd.), DL-malic acid (purchased from Beijing Bio-Top Technology Co., Ltd.), sucrose (purchased from Xilong Scientific Co., Ltd.), citric acid, DL-malic acid, sucrose, Bio-Cola from Shandong Bailailai Biotechnology Co., Ltd., and Carbon Treasure from Shandong Bailailai Biotechnology Co., Ltd.

[0026] Among them, the main component of Bio-Cola is EM enzyme bacteria agent, which is composed of probiotics such as Bacillus subtilis with high enzyme activity, Bacillus licheniformis, Brevibacillus laterosporus, Bacillus amyloliquefaciens, Lactobacillus plantarum, and their metabolites.

[0027] The main components of Carbon Treasure are Bacillus subtilis, Bacillus amyloliquefaciens, etc., among which the amino acid content is ≥2%, the organic matter content is ≥10%, and the effective viable strain count is ≥200 million / mL.

[0028] Example 1

[0029] A method for increasing the content of malonic acid in cucumbers, the specific process is as follows: Sow the cucumber germplasm material "3667" (Changchun Mici) of China Agricultural University on August 9, 2021, and then transplant it into the solar greenhouse for normal field management: maintain a suitable growth environment, such as in terms of temperature and humidity, the temperature in the greenhouse is maintained at 25 - 30°C during the day and 14 - 18°C at night, and the humidity is controlled at about 70%; in terms of fertilizer and water management, when entering the fruiting period, increase the irrigation frequency and choose to water on cool sunny days, increase the fertilization amount after harvesting the root melons, and ensure the supply of fertilizer and water during the peak fruiting period; in terms of light management, during the entire growth period, on the premise of ensuring the temperature, the covering materials should be uncovered as early as possible and covered as late as possible to allow the plants to fully receive light and extend the light time; in terms of plant adjustment, timely carry out vine hanging and remove tendrils during the growth period, and timely remove the lower old leaves and diseased leaves in the middle and late growth stages, and timely lower the vines to improve the ventilation and light transmission conditions in the field.

[0030] Starting from the initial fruiting stage (September 17, 2021), spray an exogenous preparation: sucrose aqueous solution on the cucumber plants. Among them, the sucrose aqueous solution is composed of sucrose and water, and the mass fraction of the sucrose aqueous solution is 0.50%.

[0031] The spraying method is: foliar spraying, spraying the whole plant evenly, and the amount of each spraying is 1 - 3 mL / plant, and it is best to have a slight dripping phenomenon. Each treatment is set with three replicates, spraying once every seven days, and spraying three times in total.

[0032] When the cucumber fruits reach commercial melons, take three commercial melons at the same node and bring them back to the laboratory to test the content of malonic acid in the cucumber fruits.

[0033] The detection method for the content of malonic acid in cucumber fruits is as follows:

[0034] (1) Preparation of the standard stock solution of malic acid (1 mg / mL): Accurately weigh 0.1000 g of malic acid, dissolve it in water and transfer it to a 100 mL volumetric flask, dilute it with water to the mark and mix well; Standard working solution of malic acid: Pipette the standard stock solution and dilute it step by step with water to prepare a series of standard working solutions with concentrations of 19.531 ng / mL, 39.063 ng / mL, 78.125 ng / mL, 156.25 ng / mL, and 312.5 ng / mL respectively.

[0035] (2) Use UPLC-MS / MS to test the standard working solution of malic acid. Take the relative response value obtained from the standard solution at each concentration as the ordinate and the concentration of the standard solution as the abscissa to establish a standard curve (as Figure 2 shown), and the linear equation is: y = 1.5826x - 7.38363, R 2 = 0.99, and the retention time of the malic acid standard solution is 2.41 minutes (the chromatogram of the malic acid standard working solution with a concentration of 19.531 ng / mL is as Figure 3 shown); among them, the instrument: Waters ACQUITY UPLC I-Class-Xevo TQ-S Micro ultra-high performance liquid chromatography-tandem quadrupole mass spectrometer; Chromatographic column: ACQUITY UPLCHSS T3, 1.8 μm, 2.1×100 mm; Mobile phase: A1 is acetonitrile - 1% formic acid, A2 is acetonitrile, B1 is water - 1% formic acid, B2 is water; The flow rate is 0.1 mL / min. Figure 2 This is the standard curve of malic acid.

[0036] (3) Preparation of the sample to be tested: Use a juicer to mash three commercial fruits and vegetables into a paste respectively. Take 3 2 mL centrifuge tubes and record the mass of each empty tube. Put the 3 cucumber samples into the 2 mL centrifuge tubes respectively, and then record the total weight of the centrifuge tube and the sample. Then centrifuge at 12000 r / min for 5 min using a centrifuge, take the supernatant of each sample and filter it through a 0.22 μm filter membrane, and use the 3 filtrates to be tested as the samples to be tested.

[0037] (4) Testing: Use the method in step (2) to detect the 3 samples to be tested one by one and calculate the concentration values of malic acid in the 3 samples to be tested in combination with the standard curve of the malic acid standard working solution (according to the relative response value obtained from the sample, and then read the malic acid content in the sample from the standard curve), and take the average value as the test result. The test results of Example 1 are shown in Table 1.

[0038] Example 2

[0039] A method for increasing the content of malonic acid in cucumbers, the specific process is basically the same as that in Example 1, except that: the exogenous preparation is replaced with a water solution of Carbon Treasure, wherein the water solution of Carbon Treasure is composed of Carbon Treasure and water, and the volume ratio of Carbon Treasure to water in the water solution of Carbon Treasure is 1:300; the content of malonic acid in cucumber fruits was tested and the results are shown in Table 1.

[0040] Comparative Example 1

[0041] A method for cultivating cucumbers, the specific process is basically the same as that in Example 1, except that: the exogenous preparation is replaced with water; the content of malonic acid in cucumber fruits was tested and the results are shown in Table 1.

[0042] Comparative Example 2

[0043] A method for cultivating cucumbers, the specific process is basically the same as that in Example 1, except that: the exogenous preparation is replaced with an aqueous solution of DL-malic acid, wherein the aqueous solution of DL-malic acid is composed of DL-malic acid and water, and the mass fraction of DL-malic acid in the aqueous solution of DL-malic acid is 0.05%; the content of malonic acid in cucumber fruits was tested and the results are shown in Table 1.

[0044] Comparative Example 3

[0045] A method for cultivating cucumbers, the specific process is basically the same as that in Example 1, except that: the exogenous preparation is replaced with an aqueous solution of Bio-Cola, wherein the aqueous solution of Bio-Cola is composed of Bio-Cola and water, and the volume ratio of Carbon Treasure to water in the aqueous solution of Carbon Treasure is 1:300; the content of malonic acid in cucumber fruits was tested and the results are shown in Table 1.

[0046] Comparative Example 4

[0047] A method for cultivating cucumbers, the specific process is basically the same as that in Example 1, except that: the exogenous preparation is replaced with an aqueous solution of citric acid, wherein the aqueous solution of citric acid is composed of citric acid and water, and the mass fraction of citric acid in the aqueous solution of citric acid is 0.04%; the content of malonic acid in cucumber fruits was tested and the results are shown in Table 1.

[0048] Table 1 Effects of different exogenous preparations on the content of malonic acid in cucumber fruits

[0049] Exogenous preparation Content of malonic acid (mg / kg) Comparative example 1 0.0778 Example 1 0.0959 Example 2 0.0988 Comparative example 2 0.0644 Comparative example 3 0.0743 Comparative example 4 0.0750

[0050] It can be seen from the data in Table 1 that there are differences in the content of malonic acid in cucumber fruits under different treatments with exogenous preparations. Sucrose aqueous solution and Carbon Treasure aqueous solution have a significant promoting effect on the content of malonic acid in cucumber fruits, and the content of malonic acid in cucumber fruits has increased, which are 23.3% and 27.0% higher than that of the control respectively. Among them, the Carbon Treasure aqueous solution is 27.0% higher than the control.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for increasing the content of malic acid in cucumbers, characterized in that, Spraying an exogenous preparation during the growth period of cucumber plants to increase the content of malonic acid in the cucumber; The exogenous preparation is a sucrose aqueous solution or a carbon treasure aqueous solution; The spraying is foliar spraying; The sucrose aqueous solution is composed of sucrose and water; the mass fraction of the sucrose aqueous solution is 0.50%; The carbon treasure aqueous solution is composed of carbon treasure and water; among them, the volume ratio of carbon treasure to water in the carbon treasure aqueous solution is 1:300; The carbon treasure includes Bacillus subtilis and Bacillus amyloliquefaciens; in the carbon treasure, amino acids ≥ 2%, organic matter ≥ 10%, and effective viable strains ≥ 200 million / mL.

2. The method for increasing the content of malonic acid in cucumber according to claim 1, characterized in that, The spraying frequency is: spraying once every seven days, and the total number of spraying times is three; the amount of each spraying is 1 - 3 mL / plant.

3. A method for increasing the content of malic acid in cucumber according to claim 1 or 2, characterized in that, The content of malonic acid in the cucumber is 23.3% - 27.0% higher than that of the control group; The difference between the control group and the cucumber is only that: during the growth period of cucumber plants, the sprayed exogenous preparation is replaced with clear water.

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