Microbial agent for improving drought resistance of Chinese mesona herb

Abstract

The invention belongs to the technical field of stress resistance of mesona chinensis, and particularly relates to a microbial agent for improving the drought resistance of mesona chinensis. The microbial agent for improving the drought resistance of the mesona chinensis is formed by compounding a bacillus circulans bacterial liquid and a bacillus mucilaginosus bacterial liquid, and the volume ratio of the bacillus circulans bacterial liquid to the bacillus mucilaginosus bacterial liquid is 1: (3-5). The microbial agent is formed by compounding bacillus circulans bacterial liquid and bacillus mucilaginosus bacterial liquid according to the volume ratio of 1: (3-5), and the bacillus circulans bacterial liquid and the bacillus mucilaginosus bacterial liquid are respectively obtained by culturing corresponding strains in a liquid culture medium. In the mesona chinensis planting process, damage to mesona chinensis plants under drought stress can be remarkably delayed by irrigating the microbial agent, the drought resistance of the mesona chinensis can be improved, and the microbial agent has important significance on development of the mesona chinensis industry.

Description

Technical Field

[0001] The invention belongs to the technical field of stress resistance of agar-agar grass, and particularly relates to a microbial agent for improving drought resistance of agar-agar grass. Background Art

[0002] Agar grass, also known as fairy grass, is an annual herbaceous plant of the genus Agar, Lamiaceae. It has high nutritional and medicinal value and is a plant with both medicinal and edible properties. The branches and leaves of Agar grass can be boiled to extract Agar grass glue, which is used to make Guiling jelly, fairy grass jelly, fairy grass dew and fairy grass glue. Currently, 80% of the popular herbal tea beverages on the market use Agar grass as the main raw material.

[0003] As global climate change intensifies, the frequency of drought is increasing. Drought is an important factor affecting plant growth and physiological and biochemical processes. Low soil moisture will have a serious impact on plant growth and development. The growth and development of agarwood will also be restricted by drought. Therefore, studying how to improve the drought resistance of agarwood is of great significance to the development of the agarwood industry.

[0004] The prior art discloses that graphene oxide can improve plant drought resistance. For example, “Effects of Graphene Oxide on Growth, Development and Drought Tolerance of Brassica napus” (Zhang Zishuang et al., 2023) discloses that Brassica napus was treated with 15 mg / L graphene oxide seeds. On the 10th day of drought stress, the water content and proline content of the plants were significantly increased, the tetrazolium reducibility was enhanced, and the drought resistance of Brassica napus was significantly improved.

[0005] In addition, the prior art also discloses the use of microbial agents to improve plant drought resistance. For example, "The Effects of Different Microbial Agents on Heat Tolerance and Drought Resistance of Perennial Ryegrass" (Zhang Zijia et al., 2022) discloses that Bacillus subtilis (M1), Trichoderma harzianum (M2), Bacillus licheniformis and Streptomyces tenuifolius composite agents (M3), and pink Scopulariopsis and Bacillus subtilis composite agents (M4) can all improve the drought resistance of perennial ryegrass. When treated under drought conditions for 10 days, the effects of M1 and M2 agents in optimizing various physiological indicators were the same, and both were better than the treatments with M3 and M4 agents. When treated under drought conditions for 20 days, the M2 agent had the strongest ability to improve the drought resistance of perennial ryegrass.

[0006] However, there are no reports on using microbial agents to improve the drought resistance of agar-agar grass. Summary of the invention

[0007] The purpose of the present invention is to provide a microbial agent for improving the drought resistance of agar-agar grass, so as to solve the problems existing in the prior art in the background technology.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] A microbial inoculant for improving the drought resistance of Mesona chinensis Benth., which is composed of a compound of Bacillus circulans bacterium liquid and Bacillus mucilaginosus bacterium liquid, and the volume ratio of the Bacillus circulans bacterium liquid to the Bacillus mucilaginosus bacterium liquid is 1:3 - 5.

[0010] More specifically, the bacterial content of both the Bacillus circulans bacterium liquid and the Bacillus mucilaginosus bacterium liquid is 1.0×10 7 cfu / mL.

[0011] More specifically, the preparation method of the Bacillus circulans bacterium liquid or the Bacillus mucilaginosus bacterium liquid is: inoculating the bacteria on a beef extract solid medium, culturing at 30°C for 24 h, picking a single colony and inoculating it into 5 mL of beef extract liquid medium, pre-culturing at 30°C and 200 rpm for 12 h; transferring it to fresh beef extract liquid medium according to an inoculation amount of 1%, and expanding the culture at 30°C and 200 rpm for 12 h; adding fresh beef extract liquid medium to the culture solution to adjust the bacterial content to 1.0×10 7 cfu / mL, thus obtaining the Bacillus circulans bacterium liquid or the Bacillus mucilaginosus bacterium liquid.

[0012] More specifically, the formula of the beef extract solid medium is: 3.0 g of beef extract, 10.0 g of peptone, 5.0 g of sodium chloride, 1 L of distilled water, and the pH value is 7.3 ± 0.1;

[0013] The formula of the beef extract liquid medium is: 3.0 g of beef extract, 10.0 g of peptone, 5.0 g of sodium chloride, 1 L of distilled water, and the pH value is 7.3 ± 0.1.

[0014] The present invention also provides the application of the microbial inoculant for improving the drought resistance of Mesona chinensis Benth. in improving the drought resistance of Mesona chinensis Benth.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] The microbial inoculant of the present invention is composed of a compound of Bacillus circulans bacterium liquid and Bacillus mucilaginosus bacterium liquid according to a volume ratio of 1:3 - 5. The Bacillus circulans bacterium liquid and the Bacillus mucilaginosus bacterium liquid are respectively obtained by culturing the corresponding strains in a liquid medium. During the process of planting Mesona chinensis Benth., irrigating the microbial inoculant of the present invention can significantly delay the damage to the Mesona chinensis Benth. plants under drought stress, help improve the drought resistance of Mesona chinensis Benth., and is of great significance to the development of the Mesona chinensis Benth. industry. Description of the Drawings

[0017] Figure 1 Shows the influence of different compound bacterium liquids on the relative water content of the leaves of Mesona chinensis Benth. plants under drought stress;

[0018] Figure 2Effects of different compound bacterial solutions on the root activity of Mesona chinensis plants under drought stress;

[0019] Figure 3 Effects of different compound bacterial solutions on the proline content in the leaves of Mesona chinensis plants under drought stress;

[0020] Figure 4 Effects of different compound bacterial solutions on the malondialdehyde content in the leaves of Mesona chinensis plants under drought stress. Specific implementation manners

[0021] The technical solutions of the present invention will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0022] 1. Materials and methods

[0023] 1.1 Test culture media

[0024] The formula of the beef extract solid medium is: 3.0 g of beef extract, 10.0 g of peptone, 5.0 g of sodium chloride, 15 g of agar, 1 L of distilled water, and the pH value is 7.3 ± 0.1;

[0025] The formula of the beef extract liquid medium is: 3.0 g of beef extract, 10.0 g of peptone, 5.0 g of sodium chloride, 1 L of distilled water, and the pH value is 7.3 ± 0.1.

[0026] 1.2 Bacillus circulans bacterial solution

[0027] Bacillus circulans (purchased from BeiNa Bio, numbered BNCC186120) was inoculated on the beef extract solid medium. After culturing at 30 °C for 24 h, single colonies were picked and inoculated into 5 mL of beef extract liquid medium, and pre-cultured at 30 °C and 200 rpm for 12 h; transferred to fresh beef extract liquid medium according to an inoculation amount of 1% (v / v), and expanded culture at 30 °C and 200 rpm for 12 h; fresh beef extract liquid medium was added to the culture solution to adjust the bacterial content to 1.0×10 7 cfu / mL, thus obtaining the Bacillus circulans bacterial solution.

[0028] 1.3 Bacillus mucilaginosus bacterial solution

[0029] Inoculate Bacillus mucilaginosus (purchased from Beina Biology, numbered BNCC340613) on the beef extract solid medium and culture it at 30 °C for 24 h. Pick a single colony and inoculate it into 5 mL of beef extract liquid medium, and pre-culture it at 30 °C and 200 rpm for 12 h; transfer it to fresh beef extract liquid medium according to an inoculation amount of 1% (v / v), and expand the culture at 30 °C and 200 rpm for 12 h; add fresh beef extract liquid medium to the culture solution to adjust the bacterial content to 1.0×10 7 cfu / mL.

[0030] 1.4 Drought Resistance Test

[0031] Select a composite bacterial liquid of Bacillus circulans bacterial liquid and Bacillus mucilaginosus bacterial liquid, and use Mesona chinensis Benth. as the research object to study the effect of the composite bacterial liquid on the drought resistance ability of Mesona chinensis Benth.

[0032] 1.4.1 Test Materials

[0033] Mesona chinensis Benth. of "Lingshan Daye Variety"

[0034] 1.4.2 Test Settings

[0035] See Table 1.

[0036] Table 1 Different Test Settings

[0037]

[0038] 1.4.3 Test Methods

[0039] Take field soil, air-dry it, sieve it through a 20-mesh sieve, and incorporate organic fertilizer accounting for 1% of the soil quality (purchased from Hubei Laijing Biotechnology Co., Ltd., with an organic matter content of ≥30%, implementation standard: NY / T252-2021, registration number: E Nongfei (2023) Zhunzi 4135). After mixing evenly, fill it to 4 / 5 of the pot (diameter 20 cm, height 15 cm), and use the bottom infiltration irrigation method to make the soil completely moist.

[0040] Plant Mesona chinensis Benth. seedlings that have grown to 25 cm in the pot, compact the soil at the roots after watering thoroughly with the root-fixing water, with 1 hole per pot and 3 plants per hole. Subsequently, randomly divide the seedlings into 7 groups, with 30 pots in each group. 7 days after planting, use the different proportion bacterial liquids in Research Groups 1-7 in Table 1 to treat the Mesona chinensis Benth. seedlings in each group respectively (that is, 1 kind of bacterial liquid treats 1 group of Mesona chinensis Benth. seedlings), irrigate 150 mL per pot, and irrigate once again after 7 days, for a total of 2 irrigations. Within the first 20 days after planting, irrigate 200 mL of clear water per pot every 2 days to keep the soil moist; starting from the 20th day after planting, Research Groups 1-7 stop irrigating clear water to achieve the drought stress effect. On the 3rd, 7th, and 15th days after stopping irrigating clear water (i.e., drought stress), measure the corresponding indicators. The above test conditions are all carried out under indoor ventilation and natural conditions.

[0041] 1.4.4 Measurement indicators

[0042] When measuring the indicators, 10 pots were randomly selected for each treatment, 1 plant was selected from each pot, and the average value of the measurement results was taken.

[0043] a. Relative water content of leaves

[0044] Select 3 fully expanded leaves (the positions of the selected leaves are the same among different treatment groups and avoid the top and base), wipe the surface clean and measure their fresh weight m1, place them in an oven at 85 °C until constant weight and then measure their dry weight m2, and calculate the relative water content of the leaves:

[0045] Relative water content of leaves = (m1 - m2) / m1 × 100%.

[0046] b. Root activity

[0047] The root activity of Mesona chinensis was measured by the triphenyl tetrazolium chloride method (Zhang Zijia et al., 2022).

[0048] c. Proline content

[0049] The proline content in the leaves of Mesona chinensis was measured by the sulfosalicylic acid method (Zhang Zishuang et al., 2023).

[0050] d. Malondialdehyde content

[0051] The malondialdehyde content in the leaves of Mesona chinensis was measured by the thiobarbituric acid method (Zhang Zijia et al., 2022).

[0052] 1.5 Results

[0053] The results are shown in Figures 1-4 .

[0054] It can be seen from Figure 1 that within 3 - 15 d of drought stress treatment, with the prolongation of drought stress time, the relative water content of Mesona chinensis leaves gradually decreased. The decline in Group 7 (blank control) was relatively large. By the 15th day of drought stress, the relative water content of the leaves had dropped to about 45%. The relative water content of the leaves treated with different bacterial solutions also decreased. Among them, the decline in the leaves treated with the compound bacterial solution with different ratios was smaller than that treated with the single bacterial solution. Especially when the Bacillus circulans bacterial solution and the Bacillus mucilaginosus bacterial solution were compounded and used at a volume ratio of 1:3 and 1:5, the decline in the relative water content of the leaves was the smallest. It shows that the compound bacterial solution of the present invention can maintain the relative water content of Mesona chinensis leaves and slow down the influence of drought stress on the relative water content of Mesona chinensis leaves.

[0055] It can be seen from Figure 2It can be seen that within 3 - 15 days of drought stress treatment, as the duration of drought stress prolongs, the root activity of Mesona chinensis gradually decreases. Compared with Research Group 7, the decline in root activity treated with different bacterial solutions is relatively small. Among them, when the Bacillus circulans bacterial solution and the Bacillus mucilaginosus bacterial solution are compounded and used at a volume ratio of 1:1 - 7, the decline in the root activity of Mesona chinensis is relatively slow, which helps the Mesona chinensis plants resist drought stress.

[0056] It can be seen from Figure 3 that within 3 - 15 days of drought stress treatment, as the duration of drought stress prolongs, the proline content in the leaves of Mesona chinensis gradually accumulates. The accumulation of proline helps to regulate osmosis and reduce the impact of drought stress on plants. Compared with Research Group 7, the proline accumulation amount treated with different bacterial solutions is significantly higher than that of Research Group 7. Especially when the Bacillus circulans bacterial solution and the Bacillus mucilaginosus bacterial solution are compounded and used at a volume ratio of 1:3 - 5, the proline accumulation amount in the leaves of Mesona chinensis is the most significant, indicating that the compound bacterial solution of the present invention can promote the proline accumulation of Mesona chinensis to resist drought stress.

[0057] It can be seen from Figure 4 that within 3 - 15 days of drought stress treatment, as the duration of drought stress prolongs, the malondialdehyde content in the leaves of Mesona chinensis gradually accumulates. At the 15th day of drought stress treatment, in Research Group 7, the malondialdehyde content has reached 20 nmol / g, and the membrane damage is the most serious. When different bacterial solutions are used for treatment, when the combined volume of the Bacillus circulans bacterial solution and the Bacillus mucilaginosus bacterial solution is 1:3 - 5, the malondialdehyde accumulation amount is significantly lower than that of other groups. It shows that the compound bacterial solution of the present invention can effectively slow down the membrane damage of Mesona chinensis under drought stress.

[0058] In summary, the microbial inoculant composed of the Bacillus circulans bacterial solution and the Bacillus mucilaginosus bacterial solution of the present invention can significantly delay the damage to Mesona chinensis plants under drought stress, and thus help to improve the drought resistance of Mesona chinensis.

[0059] The foregoing description of specific exemplary embodiments of the present invention is for purposes of illustration and exemplification. These descriptions are not intended to limit the present invention to the precise forms disclosed, and obviously, many changes and variations are possible in light of the above teachings. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present invention and its practical applications, so that those skilled in the art can implement and utilize various different exemplary embodiments of the present invention, as well as various different selections and changes. The scope of the present invention is intended to be defined by the claims and their equivalents.

Claims

1. A microbial inoculant for improving the drought resistance of Mesona chinensis Benth., characterized in that, It is composed of a compound of Bacillus circulans bacterial liquid and Bacillus mucilaginosus bacterial liquid, and the volume ratio of the Bacillus circulans bacterial liquid to the Bacillus mucilaginosus bacterial liquid is 1:3-5.

2. The microbial inoculant for improving the drought resistance of Mesona chinensis Benth. according to claim 1, characterized in that, The viable count of both the Bacillus circulans bacterial liquid and the Bacillus mucilaginosus bacterial liquid is 1.0×10 7 cfu / mL.

3. The microbial inoculum for improving the drought resistance of Mesona chinensis Benth. according to claim 1, characterized in that, The preparation method of the Bacillus circulans bacterial liquid or the Bacillus mucilaginosus bacterial liquid is as follows: inoculate the bacteria on the beef extract solid medium, culture at 30 °C for 24 h, pick a single colony and inoculate it into 5 mL of beef extract liquid medium, and pre-culture at 30 °C and 200 rpm for 12 h; transfer it to fresh beef extract liquid medium according to an inoculation amount of 1%, and expand the culture at 30 °C and 200 rpm for 12 h; add fresh beef extract liquid medium to the culture solution to adjust the bacterial content to 1.0×10 7 cfu / mL, thus obtaining the Bacillus circulans bacterial liquid or the Bacillus mucilaginosus bacterial liquid.

4. The microbial inoculant for improving the drought resistance of Mesona chinensis Benth. according to claim 3, characterized in that The formula of the beef extract solid medium is: 3.0 g of beef extract, 10.0 g of peptone, 5.0 g of sodium chloride, 1 L of distilled water, and the pH value is 7.3±0.1; The formula of the beef extract liquid medium is: 3.0 g of beef extract, 10.0 g of peptone, 5.0 g of sodium chloride, 1 L of distilled water, and the pH value is 7.3±0.

1.

5. Application of the microbial inoculant for improving the drought resistance of Mesona chinensis Benth. according to any one of claims 1-4 in improving the drought resistance of Mesona chinensis Benth.

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