Microbial inoculant for promoting growth of cucumber and preparation method and application thereof

Abstract

The application discloses a microbial agent for promoting growth of cucumbers, a preparation method and application thereof, and belongs to the technical field of agricultural microorganisms. The microbial agent comprises the following components: denitrifying achromobacter, Bradyrhizobium elkanii and Azotobacter vinelandii, and the volume ratio of the three is 2:1:1. The bacteria with growth promotion are reasonably combined and used, so that the mixed bacterial flora of the application is superior to a single strain in terms of growth promotion effect on cucumbers, and the synergistic effect among the bacterial strains is more adaptable in the actual soil rhizosphere complex environment. Through determination of the number of bacterial strains and mixing of specific proportions, the growth of cucumber seeds is stably and effectively promoted, the root elongation is promoted, the flowering and fruit setting rate is improved, and the plant height, plant biomass and chlorophyll content of cucumber seedlings are improved. In addition, the microbial agent can help improve the growth quality and yield of plants, reduce environmental pollution, has wide application potential in the fields of agriculture and ecology, and is worth promoting.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of agricultural microorganism technology, and particularly relates to a microbial agent for promoting the growth of cucumbers, a preparation method and application thereof. BACKGROUND

[0002] Long-term application of chemical fertilizers can increase the concentration of salts in the soil, leading to problems such as soil compaction and imbalance of acid and alkali, which can affect the growth and development of cucumbers, and even cause secondary salinization of the soil. Improper fertilization can also damage the soil structure, leading to poor soil aeration and water retention, and affecting the normal growth of cucumbers. Therefore, lack of standardized fertilization guidance can result in low crop yield, more deformed fruits, and affect the cultivation benefits. With the in-depth study of microbial agents, it has been found that microbial agents prepared from microorganisms can promote plant growth and have important practical significance for the growth regulation of cucumber plants, providing a new way for the ecological planting of cucumbers.

[0003] For example, Chinese patent CN113249243A discloses a Pseudomonas, a microbial biocontrol agent containing the bacterium, and its application, and discloses a microbial biocontrol agent containing the Pseudomonas and a preparation method thereof, as well as the application of ZL8 and its biocontrol agent in inhibiting plant pathogenic fungi and promoting plant growth. The provided biocontrol strain ZL8 has strong inhibitory effect on cucumber brown spot fungus, Sclerotinia sclerotiorum, wheat scab, potato yellow wilt, or Danshen pathogenic fungus, and has good disease control effect, growth promotion effect, and yield increasing effect in cucumber and Sanqi plants.

[0004] For another example, Chinese patent CN116286550A discloses a multifunctional Bradyrhizobium sp. strain, a microbial agent containing the same, and application thereof. The Bradyrhizobium strain is isolated from the rhizosphere soil of cucumber infected with root-knot nematode, and the fermentation supernatant of the strain has strong contact killing ability against root-knot nematode and functions of salt tolerance, dissolution of insoluble inorganic phosphorus, and secretion of auxin. The strain can not only significantly promote the growth of cucumber seedlings, but also slow down the development process of root-knot nematode in the root system of cucumber, significantly reduce the unit root knot number and egg mass number of the root system of cucumber, and is beneficial to the early prevention and control of root-knot nematode. However, the complexity and variability of the current agricultural production environment make it difficult for single-function microbial agents to fully exert their expected effects in promoting growth in practical applications.

[0005] Therefore, it is of great significance to develop mixed microbial agents of multiple microbial strains for improving the efficiency and quality of agricultural production. Microbial agents prepared from multiple microbial strains can adapt better to the complex environment in the rhizosphere of actual soil, thereby effectively promoting the growth and high yield of crops. SUMMARY

[0006] The application provides a microbial agent for promoting growth of cucumbers, a preparation method and application thereof, and the microbial agent is obtained by reasonably compounding various microbial strains, and the microbial agent stably and effectively promotes seed germination of cucumbers, promotes root elongation, improves flowering and fruit setting rate and improves yield per plant, and meanwhile, the microbial agent improves plant height, plant biomass and chlorophyll content of cucumber seedlings during the seedling stage, so that the microbial agent can promote growth of cucumber seeds and seedlings during the whole growth period.

[0007] To achieve the above technical purposes, the application adopts the following technical solutions:

[0008] A microbial agent for promoting growth of cucumbers comprises the following components: Achromobacter denitrificans, Bradyrhizobium elkanii and Azotobacter vinelandii, and the volume ratio is 2:1:1.

[0009] The Achromobacter denitrificans is purchased from the China General Microbiological Culture Collection Center (CGMCC), and the strain number is CGMCC No.1.2684; the original preservation time is July 11, 2000.

[0010] The Bradyrhizobium elkanii is purchased from the China General Microbiological Culture Collection Center (CGMCC), and the strain number is CGMCC No.1.15559; the original preservation time is December 30, 2015.

[0011] The Azotobacter vinelandii is purchased from the China General Microbiological Culture Collection Center (CGMCC), and the strain number is CGMCC No.1.7741; the original preservation time is July 24, 2008.

[0012] The three microbial strains used in the application can be purchased by querying the strain catalog of the China General Microbiological Culture Collection Center, and repeated biological preservation is not needed.

[0013] Further, the viable bacterial count of the Achromobacter denitrificans is 1×10 7 cfu / mL; the viable bacterial count of the Bradyrhizobium elkanii is 1×10 7 cfu / mL; and the viable bacterial count of the Azotobacter vinelandii is 1×10 7 cfu / mL.

[0014] Further, the microbial agent is a liquid agent.

[0015] A preparation method of a microbial agent for promoting growth of cucumbers comprises the following preparation steps:

[0016] (1) Achromobacter xylosoxidans is thawed and inoculated into the fermentation medium, and cultured at 30℃ with a stirring speed of 170r / min until the viable cell count reaches 1×10 7 cfu / mL of bacterial solution;

[0017] (2) Bradyrhizobium elkanii is thawed and inoculated into the fermentation medium, and cultured at 28℃ with a stirring speed of 180r / min until the viable cell count reaches 1×10 7 cfu / mL of bacterial solution;

[0018] (3) Azotobacter vinelandii is thawed and inoculated into the fermentation medium, and cultured at 30℃ with a stirring speed of 200r / min until the viable cell count reaches 1×10 7 cfu / mL of bacterial solution;

[0019] (4) The three bacterial solutions are mixed in a volume ratio of 2:1:1 to obtain the final product microbial agent.

[0020] Further, the preparation method of the Achromobacter xylosoxidans fermentation medium is as follows: 10g / L of proteose peptone, 3g / L of beef extract powder, 5g of NaCl, 15g of agar, and distilled water is added to 1 liter, and the pH is 7.

[0021] Further, the preparation method of the fermentation medium of Bradyrhizobium elkanii and Azotobacter vinelandii is as follows: 20g of mannitol, 15g of agar, 0.5g of yeast extract, 0.2g of KH2PO4, 0.8g of K2HPO4, 0.2g of MgSO4·7H2O, 0.1g of CaSO4·2H2O, 0.1g of FeCl3, and 0.1g of Na2MoO4·2H2O are added to 1 liter of distilled water, and the pH is 7.

[0022] Further, the microbial agent is applied to promote the growth of cucumbers.

[0023] Further, the microbial agent is applied to promote seed germination, promote root elongation, improve flowering and fruit setting rate, improve yield per plant, plant height, plant biomass and chlorophyll content of cucumber seedlings.

[0024] Further, the application method of the microbial agent is seed soaking and root application.

[0025] The microbial agent of the present application can be used for root irrigation during the plant growth stage or seedling stage. The prepared microbial agent is diluted 100 times, 100ml per plant, and applied once every two weeks. The application period includes the seedling stage, flowering stage and / or fruit setting stage of cucumbers.

[0026] The introduction of the present application can effectively promote the growth of crops, and has stronger adaptability in complex soil environment. They participate in the nitrogen cycle in the soil, optimize the transformation of nitrogen, improve the absorption and utilization efficiency of plants to nitrogen, and increase the yield of crops.

[0027] Secondly, the introduction of Bradyrhizobium elkanii can promote growth by producing plant hormones and improving plant nutrient absorption. In addition, Bradyrhizobium elkanii can indirectly improve the growth of plants by inducing systemic resistance of host plants. It can also increase the adhesion of roots to soil by releasing exopolysaccharides, thereby regulating the movement of water and soil nutrients.

[0028] In addition, the introduction of Azotobacter vinelandii can secrete various plant growth regulating hormones such as auxin (IAA), gibberellin (GA) and cytokinin (CTK), thereby promoting the growth and development of plants. These hormones not only help to increase the respiration rate and metabolism of plant roots, but also stimulate root hair formation, thereby enhancing the plant's ability to absorb minerals. In addition, Azotobacter vinelandii converts atmospheric nitrogen into ammonia nitrogen available to plants through its nitrogen fixation, providing essential nitrogen nutrition for plants. This nitrogen fixation process not only increases the nitrogen content in the soil, but also reduces the use of chemical fertilizers, thereby reducing environmental pollution.

[0029] Advantages

[0030] The mixed bacterial flora of the present application has better growth-promoting effect on cucumbers than single bacterial strain, and the synergistic effect between bacterial strains is stronger in the actual soil rhizosphere complex environment. By determining the number and specific ratio of bacterial strains, the seed germination of cucumbers is effectively promoted, the root elongation is promoted, the flowering and fruit setting rate is improved, and the yield per plant is improved, while the plant height, plant biomass and chlorophyll content of cucumber seedlings are also improved. In addition, the bacterial combination is better than the fungal combination. The bacterial culture time is shorter, and the bacterial culture efficiency is better than the fungal culture efficiency. And compared with fungi, bacteria have stronger tolerance to complex and harsh environment.

[0031] The microbial inoculant of the present application helps to improve the growth quality and yield of plants, while reducing environmental pollution, and has wide application potential in the fields of agriculture and ecology, and is worth popularizing. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 Figure 1 is a diagram of the growth state of different strains in LB medium. DETAILED DESCRIPTION

[0033] The technical solutions of the present application are further described below in conjunction with specific embodiments, but are not limited thereto.

[0034] Example 1

[0035] A preparation method of a microbial agent for promoting cucumber growth, comprising the following preparation steps:

[0036] (1) After the Achromobacter denitrificans is thawed, it is inoculated into a fermentation medium, cultured at 30 DEG C, and stirred at a speed of 170 r / min until a bacterial liquid with a viable bacterial count of 1x10 7 cfu / mL is obtained;

[0037] (2) After the Bradyrhizobium elkanii is thawed, it is inoculated into a fermentation medium, cultured at 28 DEG C, and stirred at a speed of 180 r / min until a bacterial liquid with a viable bacterial count of 1x10 7 cfu / mL is obtained;

[0038] (3) After the Azotobacter vinelandii is thawed, it is inoculated into a fermentation medium, cultured at 30 DEG C, and stirred at a speed of 200 r / min until a bacterial liquid with a viable bacterial count of 1x10 7 cfu / mL is obtained;

[0039] (4) After the three bacterial liquids are mixed according to a volume ratio of 2:1:1, a final product microbial agent is obtained.

[0040] Strain antagonism verification:

[0041] After the Achromobacter denitrificans, Bradyrhizobium elkanii and Azotobacter vinelandii preserved by freezing are activated, they are streaked on LB medium plates and cultured at 25-30 DEG C for 3-5 days.

[0042] The three bacteria are streaked on one medium, the horizontal line is Achromobacter denitrificans, the vertical line is Bradyrhizobium elkanii, and the diagonal line is Azotobacter vinelandii, so as to fully prove that there is no mutual inhibition among the strains. The culture growth state is shown in Figure 1 , and there is no obvious inhibition zone among the three bacteria, indicating that there is no obvious inhibition among them, and the compound bacterial liquid can be compounded.

[0043] Comparative Example 1

[0044] A preparation method of a microbial agent for promoting cucumber growth, comprising the following preparation steps:

[0045] (1) After the Achromobacter denitrificans is thawed, it is inoculated into a fermentation medium, cultured at 30 DEG C, and stirred at a speed of 170 r / min until a bacterial liquid with a viable bacterial count of 1x10 7 cfu / mL is obtained;

[0046] (2) After the Bradyrhizobium elkanii is thawed, it is inoculated into a fermentation medium, cultured at 28 DEG C, and stirred at a speed of 180 r / min until a bacterial liquid with a viable bacterial count of 1x10 7 cfu / mL is obtained;

[0047] (3) After the Azotobacter vinelandii is thawed, it is inoculated into the fermentation medium, and cultured at 30 DEG C, with a stirring speed of 200 r / min, until a bacterial liquid with a viable bacterial count of 1x10 7 cfu / mL is obtained;

[0048] (4) The three bacterial liquids are mixed according to a volume ratio of 1:2:1, to obtain a final product microbial agent.

[0049] Comparative Example 2

[0050] A preparation method of a microbial agent for promoting growth of cucumbers, comprising the following preparation steps:

[0051] (1) After the Achromobacter denitrificans is thawed, it is inoculated into the fermentation medium, and cultured at 30 DEG C, with a stirring speed of 170 r / min, until a bacterial liquid with a viable bacterial count of 1x10 7 cfu / mL is obtained;

[0052] (2) After the Bradyrhizobium elkanii is thawed, it is inoculated into the fermentation medium, and cultured at 28 DEG C, with a stirring speed of 180 r / min, until a bacterial liquid with a viable bacterial count of 1x10 7 cfu / mL is obtained;

[0053] (3) After the Azotobacter vinelandii is thawed, it is inoculated into the fermentation medium, and cultured at 30 DEG C, with a stirring speed of 200 r / min, until a bacterial liquid with a viable bacterial count of 1x10 7 cfu / mL is obtained;

[0054] (4) The three bacterial liquids are mixed according to a volume ratio of 1:1:2, to obtain a final product microbial agent.

[0055] Comparative Example 3

[0056] A preparation method of a microbial agent for promoting growth of cucumbers, comprising the following preparation steps:

[0057] (1) After the Achromobacter denitrificans is thawed, it is inoculated into the fermentation medium, and cultured at 30 DEG C, with a stirring speed of 170 r / min, until a bacterial liquid with a viable bacterial count of 1x10 7 cfu / mL is obtained;

[0058] (2) After the Bradyrhizobium elkanii is thawed, it is inoculated into the fermentation medium, and cultured at 28 DEG C, with a stirring speed of 180 r / min, until a bacterial liquid with a viable bacterial count of 1x10 7 cfu / mL is obtained;

[0059] (3) After the Azotobacter vinelandii is thawed, it is inoculated into the fermentation medium, and cultured at 30 DEG C, with a stirring speed of 200 r / min, until a bacterial liquid with a viable bacterial count of 1x10 7 cfu / mL is obtained;

[0060] (4) The three bacterial liquids are mixed in a volume ratio of 1:1:1 to obtain the final product microbial inoculant.

[0061] Comparative Example 4

[0062] A preparation method of a microbial inoculant for promoting the growth of cucumbers includes the following preparation steps:

[0063] (1) After the Azotobacter vinelandii is thawed, it is inoculated into a fermentation medium and cultured at 30°C, with a stirring speed of 170 r / min, until a bacterial liquid with a viable bacterial count of 1×10 7 cfu / mL is obtained;

[0064] (2) After the Bradyrhizobium elkanii is thawed, it is inoculated into a fermentation medium and cultured at 28°C, with a stirring speed of 180 r / min, until a bacterial liquid with a viable bacterial count of 1×10 7 cfu / mL is obtained;

[0065] (3) The two bacterial liquids are mixed in a volume ratio of 2:1 to obtain the final product microbial inoculant.

[0066] This comparative example does not add Bradyrhizobium elkanii, and the remaining raw materials and steps are the same as in Example 1.

[0067] Comparative Example 5

[0068] A preparation method of a microbial inoculant for promoting the growth of cucumbers includes the following preparation steps:

[0069] (1) After the Azotobacter vinelandii is thawed, it is inoculated into a fermentation medium and cultured at 30°C, with a stirring speed of 170 r / min, until a bacterial liquid with a viable bacterial count of 1×10 7 cfu / mL is obtained;

[0070] (2) After the Bradyrhizobium elkanii is thawed, it is inoculated into a fermentation medium and cultured at 28°C, with a stirring speed of 180 r / min, until a bacterial liquid with a viable bacterial count of 1×10 7 cfu / mL is obtained;

[0071] (3) The two bacterial liquids are mixed in a volume ratio of 2:1 to obtain the final product microbial inoculant.

[0072] This comparative example does not add Bradyrhizobium elkanii, and the remaining raw materials and steps are the same as in Example 1.

[0073] Comparative Example 6

[0074] A preparation method of a microbial inoculant for promoting the growth of cucumbers includes the following preparation steps:

[0075] (1) After the Bradyrhizobium elkanii was thawed, it was inoculated into fermentation medium and cultured at 28°C with a stirring speed of 180 r / min until a bacterial liquid with a viable bacterial count of 1 x 10 7 cfu / mL was obtained;

[0076] (2) After the Azotobacter vinelandii was thawed, it was inoculated into fermentation medium and cultured at 30°C with a stirring speed of 200 r / min until a bacterial liquid with a viable bacterial count of 1 x 10 7 cfu / mL was obtained;

[0077] (3) After the two bacterial liquids were mixed according to a volume ratio of 1:1, a final product microbial inoculant was obtained.

[0078] The comparative example does not add Paracoccus denitrificans, and the rest of the raw materials and steps are the same as those in Example 1.

[0079] Performance test

[0080] Test 1: Seed germination rate determination

[0081] Full-grain, undamaged Zhongnong 116 cucumber seeds were selected, 120 seeds were taken as a group, and Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 3, Comparative Example 4, Comparative Example 5, Comparative Example 6 and a blank control were set up, a total of 8 groups.

[0082] Seed treatment: the cucumber seeds were surface sterilized by soaking in 75% alcohol for 30 s, washed once with sterile water, soaked in 6% sodium hypochlorite for 15 min, shaken from time to time during the period, and then the sodium hypochlorite was poured out and the seeds were washed with sterilized water for 6 times. Then the seeds were soaked in 50°C warm water for 1 h, the surface water of the seeds was absorbed with absorbent paper, and then the seeds were soaked in the solutions of Example and Comparative Examples and the blank control for 10 h, and then placed in a culture dish for culture.

[0083] Each treatment was set up: the aqueous solutions of the microbial inoculants of Example and Comparative Examples were diluted 100 times, and the blank control group was treated with the same amount of water. The cucumber seeds of each group were placed in a 100 x 100 mm culture dish, 2 layers of filter paper were added to the bottom of the culture dish, and 40 seeds were evenly placed in each culture dish, with 3 repeats for each treatment. After soaking in the solutions of Example and Comparative Examples and the blank control for 10 h, 5 mL of purified water was added to each culture dish, and 1 mL of purified water was supplemented every day. After dark culture in a 25°C incubator for 5 d, the number of germinated seeds in each group was counted, and the germination rate was calculated and shown in Table 1.

[0084] The germination rate % = (germinated seeds / tested seeds) x 100%, and the length of the cucumber seed white part was greater than or equal to 80% as germination.

[0085] Table 1: 5-day germination of cucumber seeds after seed soaking with different solutions

[0086]

[0087] As shown in Table 1, the seed germination rate is greatly improved by using the microbial inoculant of Example 1.

[0088] Test 2: determination of root growth

[0089] Full-grain, undamaged Zhongnong 116 cucumber seeds were selected, 60 seeds were taken as a group, and Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 3, Comparative Example 4, Comparative Example 5, Comparative Example 6 and blank control were set up, a total of 8 groups.

[0090] Seed treatment: the cucumber seeds were surface sterilized by soaking in 75% alcohol for 30s, washed once with sterile water, soaked in 6% sodium hypochlorite for 15min, shaken from time to time during the period, and then the sodium hypochlorite was poured out, the seeds were washed with sterilized water for 6 times, then soaked in 50℃ warm water for 1h, the surface water of the seeds was absorbed with absorbent paper, then soaked in the solutions of Example and Comparative Examples and blank control for 10h, washed with distilled water, and then placed in a culture dish.

[0091] Each treatment setting: the microbial inoculants of Example and Comparative Examples were diluted 100 times in water, and the blank control group and the same amount of water were used to soak the cucumber seeds for 10h. After the cucumber seeds in each group were washed with distilled water, the seeds were placed in a 100x100mm culture dish, 2 layers of filter paper were added to the bottom of the culture dish, 20 seeds were evenly placed in each culture dish, and each treatment was repeated 3 times. 5mL purified water was added to each culture dish, and 1mL purified water was supplemented every day. After dark culture in a 25℃ incubator for 5d, 10 seedlings were randomly taken from each culture dish, and the main root length and the number of first-order lateral roots of each seedling were measured in Table 2. The results of each experimental group were averaged.

[0092] Table 2 Root growth of cucumber seeds after soaking in different solutions for 5d

[0093] Group Main root length / cm Number of primary lateral roots Blank control 3.25 2.9 Example 1 4.57 5.3 Comparative example 1 3.46 3.7 Comparative example 2 3.91 3.9 Comparative example 3 3.64 4.5 Comparative example 4 3.43 3.5 Comparative example 5 3.41 3.5 Comparative example 6 3.36 3.3

[0094] As shown in Table 2, the main root length and the number of first-order lateral roots of Example 1 are better than those of blank control and each comparative example. The main root length of Example 1 is increased by 40.6% compared with blank control, and the number of first-order lateral roots is increased by 76.7% compared with blank control, which proves that Example 1 can significantly promote the main root length and the number of first-order lateral roots of cucumber seedlings.

[0095] Test 3

[0096] Select the full and no breakage of Zhongnong 116 cucumber seeds, 30 grains for a group, respectively, set example 1, comparative example 1, comparative example 2, comparative example 3, comparative example 4, comparative example 5, comparative example 6 and blank control each group, a total of 8 groups.

[0097] Seed treatment: the cucumber seeds were soaked with 75% alcohol for 30s for surface sterilization, washed once with sterile water, then soaked with 6% sodium hypochlorite for 15min, shake from time to time, pour out the sodium hypochlorite, rinse 6 times with sterilized water, then soak the seeds in 50℃ warm water for 1h, clean with distilled water and dry for standby.

[0098] Each treatment setting: put the treated cucumber seeds in each group into 100x100mm culture dish, add 2 layers of filter paper at the bottom of the culture dish, evenly place 10 seeds in each culture dish, repeat 3 times for each treatment. Add 5mL purified water to each culture dish, supplement 1mL purified water every day, place in 25℃ incubator for dark culture for 5d, then randomly take out 5 seedlings of each group with the same growth potential from each culture dish, inoculate the seedlings in each group into the seedling box, then take 100ml of microbial inoculant of example and comparative example diluted 100 times in water, blank control and water irrigation in each group of seedling box, measure the biomass of the plants when the cucumber seedlings are 30d, and the growth promoting effect is shown in table 3.

[0099] Table 3 biomass of cucumber plants after root irrigation with different solutions

[0100] Group Plant height / cm Fresh weight of aboveground part / g Dry weight of aboveground part / g Chlorophyll content mg / L Blank control 16.5 4.1 0.77 9.73 Example 1 21.3 8.1 1.42 20.12 Comparative example 1 18.9 6.9 1.24 17.43 Comparative example 2 19.4 7.3 1.29 17.81 Comparative example 3 20.1 7.6 1.35 18.25 Comparative example 4 17.6 5.4 0.98 13.69 Comparative example 5 17.8 5.7 1.04 13.94 Comparative example 6 16.9 5.1 0.95 11.28

[0101] As shown in table 3, after planting for 30 days, the use of microbial inoculant of example 1 of the application compared with blank control, the plant height, aboveground fresh weight, aboveground dry weight and chlorophyll of cucumber were increased by 29.1%, 97.6%, 84.4%, 106.7% respectively, indicating that the microbial inoculant of the application has obvious promoting effect on the growth of cucumber seedlings. In addition, compared with example 1 of the application, the change of strain ratio in comparative examples reduces the indicators of promoting the growth of cucumber seedlings, indicating that the specific strain ratio of example 1 of the application can play the maximum effect.

[0102] Test 4 determination of flowering, fruit setting and yield

[0103] Select the three-leaf one heart of cucumber seedlings to transplant and plant in the greenhouse, set example 1, comparative example 1, comparative example 2, comparative example 3, comparative example 4, comparative example 5, comparative example 6 and blank control, a total of 8 groups. Each group selects 10 seedlings with the same growth and health to plant, and sets a blank control group as a protection row between groups. After planting for one week, the microbial inoculant prepared in each group is diluted by 100 times, the blank control is treated with equal amount of water for root irrigation, each group irrigates 100ml, and irrigates once again after two weeks. After one and a half months of planting, the number of flowers of each group is counted, and after one week, the number of fruits (length greater than 5cm) of each group is counted, then the 5-day total yield of each group is counted, and the data statistics are shown in Table 4.

[0104] Table 4 Flowering and fruit setting and yield of cucumber plants treated with different solutions

[0105]

[0106]

[0107] From Table 4, the number of flowers per plant, the number of fruits per plant, the weight of single fruit, and the yield per plant of example 1 are higher than those of the blank control group and the comparative example group. The data of example 1 compared with the blank control shows that example 1 has a significant promoting effect on the number of flowers per plant, the number of fruits per plant, the weight of single fruit, and the yield per plant. In addition, the data of example 1 compared with the data of each comparative example shows that the data of example 1 is also better than that of the comparative example, which shows that the specific ratio of the three bacteria in the present application can maximize the growth-promoting effect of cucumber.

[0108] It should be noted that the above examples are only preferred embodiments of the preferred mode of implementing the present application, not all embodiments. Obviously, based on the above examples of the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor should be within the scope of protection of the present application.

Claims

1. A microbial inoculant for promoting growth of cucumber, characterized by, Composed of: Achromobacter denitrificans (ATCC 8559) Achromobacter denitrificans ), Bradyrhizobium elkanii (ATCC 49946) Bradyrhizobium elkanii ), and Azotobacter vinelandii (ATCC 29610) Azotobacter vinelandii ). The denitrifying achromobacter is purchased from China General Microbiological Culture Collection Center (CGMCC), and the strain number is CGMCC No. 1.2684; the original preservation time is July 11, 2000; The Bradyrhizobium elkanii is purchased from China General Microbiological Culture Collection Center (CGMCC), and the strain number is CGMCC No. 1.15559; the original preservation time is December 30, 2015; The Azotobacter vinelandii is purchased from China General Microbiological Culture Collection Center (CGMCC), and the strain number is CGMCC No. 1.7741; the original preservation time is July 24, 2008; and the preparation method of the microbial agent comprises the following steps: (1) After the Achromobacter denitrificans is thawed, it is inoculated into a fermentation medium, and cultured at 30°C with a stirring speed of 170 r / min until a bacterial liquid with a viable bacterial count of 1×10 7 cfu / mL is obtained; (2) After the Bradyrhizobium elkanii is thawed, it is inoculated into the fermentation medium, and cultured at 28°C with a stirring speed of 180 r / min until the viable cell count reaches 1×10 7 cfu / mL of the bacterial solution; (3) After the Azotobacter vinelandii is thawed, it is inoculated into the fermentation medium, and cultured at 30°C with a stirring speed of 200 r / min until a bacterial liquid with a viable bacterial count of 1×10 7 cfu / mL is obtained; (4) mixing the three kinds of bacterial liquid according to the volume ratio of 2:1:1 to obtain the final product microbial agent.

2. The microbial inoculant for promoting growth of cucumber according to claim 1, characterized in that, The microbial agent is a liquid agent.

3. The microbial agent of any one of claims 1-2 in promoting the growth of cucumber.

4. The use of the microbial inoculant according to claim 3 for promoting the growth of cucumber, characterized in that, The application of the microbial agent in promoting seed germination, promoting root elongation, improving flowering and fruit setting rate, improving yield per plant, plant height, plant biomass and chlorophyll content of cucumber seedling stage.

5. The use of the microbial inoculant according to claim 4 for promoting the growth of cucumber, characterized in that, The application method is seed soaking and root application.

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