Application of Aegiceras corniculatum Extract in Controlling Snails and / or Reducing Soil Methane Emissions
By using ethyl acetate and ethanol extract from candle fruit leaves, the problems of Fushoushou snail prevention and control and soil methane emissions were solved, effective control of Fushou snail and significant reduction of methane emissions in rice fields were achieved, and the application effect of environmentally friendly low-carbon agriculture was achieved.
Patent Information
- Application Number
- CN202310249177.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-03-15
- Publication Date
- 2025-07-04
- Estimated Expiration
- 2043-03-15
AI Technical Summary
In the prior art, chemical agents have problems of environmental pollution and high economic costs in preventing and controlling snails. At the same time, plant extracts ignore the behavioral laws of invasion harm of snails during the snail killing process, resulting in waste of resources and increased costs; while research on plant extracts in reducing soil methane emissions has not yet received widespread attention.
Using candle fruit leaf extract, especially its ethyl acetate and ethanol extract, to inhibit the behavior of the Fushou Snail, kill the Fushou Snail, and significantly reduce the methane emissions in the soil of the paddy field by mixing different concentrations or using it alone.
At a certain concentration, candle fruit leaf extract can effectively control the Fushou snail, reduce its feeding activities, protect rice seedlings, and significantly reduce methane emissions in the rice field, realizing the integrated application of environmentally friendly low-carbon agricultural technology.
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Figure CN116439257B_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of low-carbon utilization of plant resources, and relates to the application of Aegiceras corniculatum extract in controlling snails and / or reducing methane emissions from soil (especially paddy soil); the specific application method involves three aspects: First, the extract of the leaves of the mangrove plant Aegiceras corniculatum can inhibit Pomacea canaliculata; Second, the extract of the leaves of the mangrove plant Aegiceras corniculatum can kill Pomacea canaliculata; Third, the extract of the leaves of the mangrove plant Aegiceras corniculatum can reduce methane emissions from soil (especially paddy soil). Background Art
[0002] As a dangerous and harmful invasive organism, Pomacea canaliculata has attracted much attention around the world in recent years. Pomacea canaliculata is one of the world's 100 worst invasive alien species designated by ISSG, and it is also one of the harmful alien organisms first listed as invading China by the former State Environmental Protection Administration. The strong reproductive ability, wide feeding habits and large food intake of Pomacea canaliculata can easily lead to crop yield reduction, especially the harm to aquatic crops such as rice, water bamboo, lotus root, etc. is more serious. The invasion of Pomacea canaliculata also poses a serious threat to the service functions of wetland ecosystems. At present, chemical control is the main method for controlling Pomacea canaliculata. However, conventional chemically synthesized molluscicides are easy to pollute the water and soil environment, and there are also problems such as high economic costs and affecting the energy and material flow cycle in the ecosystem.
[0003] The development and utilization of plant resources provide an important way for biological control of snails. The control of snails by plant extracts is green and environmentally friendly, and has the characteristics of low toxicity, low toxicity, many types, wide sources, and green environmental protection. China has a wide variety of plant species and high diversity, which provides a material basis for controlling snails with plant extracts. However, the current plant extracts only focus on the snail-killing effect, and the behavior law of the harm caused by the invasion of Pomacea canaliculata is ignored during the application process. The "simple and crude" snail-killing method easily causes waste of resources and cost increase, which limits its popularization and use.
[0004] Methane (CH4) is a powerful greenhouse gas second only to carbon dioxide. On the 20-year and 100-year scales, its global warming potential is 84 times and 28 times that of carbon dioxide respectively. Reducing CH4 emissions can effectively reduce the global warming trend in the near future. Paddy fields are the main source of CH4 emissions in crop systems. Climate change has gradually become a global problem threatening agricultural production. How to effectively reduce CH4 emissions from paddy soil has become the focus of agricultural attention. However, the research on whether plant extracts can be used to reduce soil methane emissions is still blank and has not received extensive attention.
[0005] Plant extracts have potential value in controlling Pomacea canaliculata and reducing soil methane emissions, and there is still much room for research on this snail-control and low-carbon effect. Aegiceras corniculata belongs to the genus Aegiceras of the family Myrsinaceae and is a typical mangrove plant in South China. Aegiceras corniculata has a large amount of fallen leaves every year. The total litter amount of the Aegiceras corniculata community in Guangxi Pearl Bay alone can reach 3710 kg per hectare per year. These fallen leaves accumulate in the mangrove wetland in large quantities and become potential resources. The alcohols and quinones contained in the leaves of Aegiceras corniculata have bactericidal properties, and their effects are related to the antibacterial and antioxidant activities of sterols, triterpenes, quinones, flavonoids, and organic acids in the leaves. However, there is no report on using Aegiceras corniculata to control Pomacea canaliculata in paddy fields and reduce methane emissions from the soil. Summary of the Invention
[0006] In order to overcome the disadvantages and deficiencies of the prior art, the purpose of the present invention is to provide an application of Aegiceras corniculata extract in snail control and / or reducing soil methane emissions. This extract can not only inhibit and kill Pomacea canaliculata but also reduce methane emissions from paddy field soil.
[0007] The harm of Pomacea canaliculata mainly focuses on the rice transplanting period in paddy fields. Its massive feeding on rice seedlings causes a reduction in production. The present invention creatively utilizes the characteristic of the Aegiceras corniculata leaf extract to inhibit the activities of Pomacea canaliculata, protects rice seedlings by reducing and even completely controlling the feeding activities of Pomacea canaliculata in a short time. At the same time, the present invention discovers that the Aegiceras corniculata leaf extract has a significant effect of reducing methane release from paddy field soil. These two characteristics make the Aegiceras corniculata leaf extract have unique value and great application prospects in the low-carbon snail control technology in paddy fields, and cleverly realizes the integrated application of low-carbon agricultural technology.
[0008] The purpose of the present invention is achieved by the following technical solutions:
[0009] Application of Aegiceras corniculata extract in snail control and / or reducing soil methane emissions.
[0010] Further, the Aegiceras corniculata extract is an Aegiceras corniculata leaf extract;
[0011] Further, the Aegiceras corniculata leaf extract is at least one of an Aegiceras corniculata leaf ethyl acetate extract and an Aegiceras corniculata leaf ethanol extract; furthermore, the mass ratio of the Aegiceras corniculata leaf ethanol extract to the Aegiceras corniculata leaf ethyl acetate extract is 1:20 - 3:40.
[0012] When using only the Aegiceras corniculata leaf ethyl acetate extract, the final concentration of the Aegiceras corniculata leaf ethyl acetate extract is 0.20 - 0.40 g / L.
[0013] When using the ethanol extract of Aegiceras corniculatum leaves alone, the final concentration of the ethanol extract of Aegiceras corniculatum leaves is 0.02 - 0.035 g / L; further preferably 0.02 - 0.03 g / L; even more preferably 0.03 g / L;
[0014] When the ethyl acetate extract of Aegiceras corniculatum leaves is mixed with the ethanol extract of Aegiceras corniculatum leaves, the final concentration of the mixed extract is 0.30 - 0.50 g / L; further preferably 0.3 - 0.40 g / L; even more preferably 0.32 - 0.4 g / L;
[0015] Further, the snail is Pomacea canaliculata.
[0016] Further, the soil is paddy soil.
[0017] Preferably, the application is as follows:
[0018] (1) The application of the ethyl acetate extract of Aegiceras corniculatum leaves in inhibiting Pomacea canaliculata; and / or
[0019] (2) The application of the ethanol extract of Aegiceras corniculatum leaves, the mixture of the ethyl acetate extract and the ethanol extract of Aegiceras corniculatum leaves in killing Pomacea canaliculata; and / or
[0020] (3) The application of the ethyl acetate extract and / or the ethanol extract of Aegiceras corniculatum leaves in reducing soil methane emissions.
[0021] Preferably, the dosage of the ethyl acetate extract of Aegiceras corniculatum leaves in reducing soil methane emissions is 0.20 - 0.40 g / L, and further preferably 0.40 g / L.
[0022] Preferably, the dosage of the ethanol extract of Aegiceras corniculatum leaves in reducing soil methane emissions is 0.02 - 0.035 g / L; further preferably 0.02 - 0.03 g / L; even more preferably 0.03 g / L;
[0023] Preferably, the dosage of the mixture of the ethyl acetate extract and the ethanol extract of Aegiceras corniculatum leaves in reducing soil methane emissions is 0.30 - 0.50 g / L, further preferably 0.30 - 0.40 g / L, and even more preferably 0.32 - 0.40 g / L.
[0024] The application includes the steps:
[0025] Add the Aegiceras corniculata leaf extract to the water body containing Pomacea canaliculata. Among them, when the Aegiceras corniculata leaf extract is the ethyl acetate extract, its dosage is 0.20 - 0.40 g / L; when the Aegiceras corniculata leaf extract is the ethanol extract, its dosage is 0.02 - 0.035 g / L; when the Aegiceras corniculata leaf extract is a mixture of the ethyl acetate extract and the ethanol extract, its dosage is 0.30 - 0.50 g / L, and the mass ratio of the ethanol extract to the ethyl acetate extract is 1:20 - 3:40;
[0026] Preferably, the water body is a paddy field water body.
[0027] In the scheme, the Aegiceras corniculata leaf mentioned is Aegiceras corniculata, which belongs to the genus Aegiceras of the family Myrsinaceae. The behavioral responses of Pomacea canaliculata include three states: inhibition, semi-inhibition, and normal. The inhibition state includes behaviors such as closing the operculum, foraging, and escaping. Semi-inhibition includes behaviors such as attaching to the wall and escaping. Normal behavior is judged as continuous movement at the bottom of the water. The methane emission from paddy field soil is continuously measured using a LI-7810 portable greenhouse gas analyzer. The experiment shows that the dosage of the ethyl acetate extract of Aegiceras corniculata leaf affects the behavioral response of Pomacea canaliculata. When the dose >= 0.20 g / L, the behavior of Pomacea canaliculata produces a response, and Pomacea canaliculata is in the inhibition and semi-inhibition states, unable to forage, and the methane emission from paddy field soil is significantly reduced. The ethyl acetate extract has a negative effect on the methane production process of paddy field soil and a positive effect on the methane oxidation process of paddy field soil. While < 0.20 g / L has no obvious effect on the normal foraging activity of Pomacea canaliculata, the defense of its internal physiological metabolism is sufficient to cope with the interference of the extract, and it has no obvious effect on the methane emission from paddy field soil. Preferably, the dosage of the ethyl acetate extract of Aegiceras corniculata leaf is 0.40 g / L. At this dosage, the inhibitory effect on Pomacea canaliculata is obvious, and it can effectively reduce the methane emission from paddy fields.
[0028] The death of Pomacea canaliculata is characterized by the protrusion of the abdominal foot and no longer retracting. After gently pulling, the phenomenon of shell and flesh separation occurs in Pomacea canaliculata. The dosage of the ethanol extract of Aegiceras corniculata leaf directly affects the effect of killing Pomacea canaliculata. When the effective dose of the ethanol extract >= 0.02 g / L, Pomacea canaliculata begins to die, and the mortality rate increases with the increase in concentration. Below 0.02 g / L, the survival of Pomacea canaliculata is not significantly affected, and there is partial damage to the organ tissues of Pomacea canaliculata. Pomacea canaliculata maintains normal growth and reproduction through its self-repair mechanism. It has been experimentally proven that the lower limit of the dosage of the ethanol extract is 0.02 g / L. Below this dosage, it cannot play a toxic role in Pomacea canaliculata. Preferably, the dosage of the ethanol extract of Aegiceras corniculata leaf is 0.03 g / L. At this dosage, the time required to kill 100% of Pomacea canaliculata is approximately 72 h.
[0029] The dosage of the mixture of the ethanol extract and ethyl acetate extract of Aegiceras corniculatum leaves affects the efficacy of killing Pomacea canaliculata and reducing methane emissions. The death of Pomacea canaliculata is characterized by the protrusion of the abdominal foot and no longer retracting. After gently pulling, the phenomenon of shell and flesh separation occurs in Pomacea canaliculata. When the mixing ratio of the mixed extract >= 1:20 (ethanol extract: ethyl acetate extract >= 1:20), Pomacea canaliculata begins to die. As the concentration increases, the mortality rate increases; and the methane emission from paddy soil is significantly reduced. The mixed extract shows a negative effect on the methane production process in paddy soil and a positive effect on the methane oxidation process in paddy soil. As the content of ethyl acetate extract increases, the effect of reducing methane emissions increases. Therefore, the ratio of ethanol extract to ethyl acetate extract is 1:20 - 3:40. Beyond this range, the mixed extract cannot achieve the dual effects of killing snails and reducing methane emissions. Preferably, the dosage of the mixed extract of Aegiceras corniculatum leaves is 0.32 - 0.4 g / L (the ratio of ethanol extract to ethyl acetate extract is 1:15. At this dosage, the time required to kill 100% of Pomacea canaliculata is about 72 h, and it can also reduce the methane emission from paddy soil).
[0030] The preparation method of the ethyl acetate extract of Aegiceras corniculatum leaves comprises the following steps:
[0031] Dissolve the ethanol extract of Aegiceras corniculatum leaves in water, add ethyl acetate for extraction, repeat extraction until the color of the upper-layer ethyl acetate does not change, combine the extraction solutions, rotary evaporate and dry to obtain the ethyl acetate extract of Aegiceras corniculatum leaves.
[0032] Preferably, the mass ratio of the ethanol extract of Aegiceras corniculatum leaves to water is 2.5 - 3.5:1; further preferably 3:1.
[0033] The preparation method of the ethanol extract of Aegiceras corniculatum leaves comprises the following steps:
[0034] Take Aegiceras corniculatum leaves, wash, air-dry, cut into pieces, dry and pulverize, sieve through a 30 - 70 mesh sieve to obtain Aegiceras corniculatum leaf powder; then soak with an ethanol aqueous solution, extract by ultrasonic wave, filter and extract the solid residue 1 - 2 more times, combine the filtrates, dry to obtain the ethanol extract of Aegiceras corniculatum leaves;
[0035] Preferably, the drying is carried out at 55 - 65 °C for 22 - 25 hours; further preferably at 60 °C for 24 hours;
[0036] Preferably, the mass-to-volume ratio of the Aegiceras corniculatum leaf powder to the ethanol aqueous solution is 1:15 - 20; further preferably 1:20.
[0037] Preferably, the volume fraction of ethanol in the ethanol aqueous solution is 65 - 75%; further preferably 70%.
[0038] Preferably, the soaking time is 22 - 25 h; further preferably 24 h;
[0039] Preferably, the soaking is carried out at room temperature, which refers to 23 - 27°C;
[0040] Preferably, the time for ultrasonic extraction is 25 - 36 min; more preferably 30 min;
[0041] The morphology of Aegiceras corniculatum leaves, especially the particle size of the powder, will also affect the extraction effect, as well as the efficiency of inhibiting the behavior of Pomacea canaliculata and killing Pomacea canaliculata. If it exceeds the range of 30 - mesh sieve and 70 - mesh sieve, it is difficult to obtain plant extracts, or effectively inhibit the effect on Pomacea canaliculata, or achieve the effect of 100% killing of Pomacea canaliculata. Preferably, the sieving through 30 - 70 mesh is through 60 - mesh; the powder of Aegiceras corniculatum leaves of this size is more likely to be used to obtain extracts and can most effectively inhibit or kill Pomacea canaliculata.
[0042] The present invention has the following advantages and effects compared with the prior art:
[0043] (1) The plant material Aegiceras corniculatum is a common plant in the mangrove wetlands of South China, with abundant fallen leaves and easy access;
[0044] (2) It is beneficial to the ecological control of invasive organisms and has great reference value for the research of invasion ecology and biological invasion control technology;
[0045] (3) Through the extract of Aegiceras corniculatum leaves, Pomacea canaliculata can be effectively controlled or killed under a certain dosage, and it can reduce the methane emission of paddy field soil, having the dual effects of environmental friendliness and greenhouse gas emission reduction, and having certain reference value for the research of greenhouse gas emission reduction in paddy field soil. Description of the Drawings
[0046] Figure 1 It is the snail - inhibiting effect of 0.2 g / L ethyl acetate extract solution of Aegiceras corniculatum leaves.
[0047] Figure 2 It is the snail - inhibiting effect of 0.3 g / L ethyl acetate extract solution of Aegiceras corniculatum leaves
[0048] Figure 3 It is the snail - inhibiting effect of 0.4 g / L ethyl acetate extract solution of Aegiceras corniculatum leaves
[0049] Figure 4 It is the methane emission rate (ppbv / min) of the control group and the treatment groups with 0.20 and 0.30 g / L ethyl acetate extract of Aegiceras corniculatum leaves.
[0050] Figure 5 It is the methane emission rate (ppbv / min) of the control group and the treatment group with 0.40 g / L ethyl acetate extract of Aegiceras corniculatum leaves.
[0051] Figure 6 is the methane emission rate (ppbv / min) of the control group and the treatment groups with ethanol extracts of Aegiceras corniculatum leaves at different concentrations.
[0052] Figure 7 is the methane emission rate (ppbv / min) of the control group and the groups with mixed extracts at 0.32, 0.368, and 0.4 g / L.
[0053] Figure 8 is the comparison of the mortality rate (3 days after dosing) and soil methane emissions between the control group and the groups with mixed extracts at 0.32, 0.368, and 0.4 g / L. Specific Embodiments
[0054] The present invention will be further described in detail below in conjunction with embodiments and the accompanying drawings, but the embodiments of the present invention are not limited thereto.
[0055] For the test methods without specific experimental conditions noted in the following embodiments, they are generally carried out according to conventional experimental conditions or the experimental conditions recommended by the manufacturer. The materials, reagents, etc. used, unless otherwise specified, are reagents and materials obtained from commercial sources.
[0056] Embodiment 1
[0057] This embodiment provides a method for inhibiting the behavior of Pomacea canaliculata using the ethyl acetate extract of Aegiceras corniculatum leaves. The specific steps include:
[0058] (1) Collect the whole Aegiceras corniculatum leaves, wash the plant materials, air-dry them in a ventilated place, and cut them into pieces.
[0059] (2) The cut plant materials are dried in a constant-temperature blast drying oven at 60 °C for 24 h, crushed by a plant sample grinder, passed through a 60-mesh sieve, and the dry powder samples are sealed in plastic bags and stored in a desiccator for later use.
[0060] (3) The dry powder plant materials (200 grams) are soaked in 70% ethanol at a ratio of 1:20 (mass: volume) at room temperature (23 - 27 °C) for 24 hours, and then ultrasonically extracted for 30 minutes. Then the samples are filtered.
[0061] (4) As described in (3), the solid residue is extracted two more times. The three filtrates are combined and then evaporated to dryness under vacuum to obtain the ethanol extract of Aegiceras corniculatum leaves. Part of the ethanol extract is suspended in distilled water and extracted with ethyl acetate to obtain the ethyl acetate extract of Aegiceras corniculatum leaves. Weigh a certain amount of the ethyl acetate extract in dechlorinated water and disperse (dissolve) the extract with ultrasonic waves to prepare a stock solution with a concentration of 5 g / L.
[0062] (5) Toxicity test: Take 40 mL, 60 mL, and 80 mL of the mother liquor of the ethyl acetate extract respectively, and make up the volume to 1 L to obtain ethyl acetate extract solutions with concentrations of 0.2 g / L, 0.3 g / L, and 0.4 g / L respectively. Add 10 Pomacea canaliculata to each concentration of the extract solution, and the inhibitory effect on Pomacea canaliculata is as shown in Figure 1 , Figure 2 and Figure 3 . Among them, the ethyl acetate extract is not added to the control group. The results show that the inhibition rate and half-inhibition rate of the 0.2 g / L treatment on Pomacea canaliculata for 24 h reach 20% and 60%, and the inhibition rate and half-inhibition rate for 96 h reach 60% and 40% ( Figure 1 ). The inhibition rate and half-inhibition rate of the 0.3 g / L treatment on Pomacea canaliculata for 24 h reach 30% and 50%, and the inhibition rate and half-inhibition rate for 96 h reach 80% and 20% ( Figure 2 ). The inhibition rate and half-inhibition rate of the 0.4 g / L treatment on Pomacea canaliculata for 24 h reach 40% and 50%, and the inhibition rate and half-inhibition rate for 96 h reach 90% and 10% ( Figure 3 ).
[0063] Example 2
[0064] This example provides a method for reducing methane emissions in paddy fields using the ethyl acetate extract of Aegiceras corniculatum leaves. The specific steps include:
[0065] (1) Collect the whole Aegiceras corniculatum leaves, wash the plant materials clean, dry them in a ventilated place, and cut them into pieces;
[0066] (2) The cut plant materials are dried in a constant temperature blast drying oven at 60 °C for 24 h, crushed by a plant sample crusher, passed through a 60-mesh sieve, and the dry powder samples are sealed in plastic bags and stored in a desiccator for later use;
[0067] (3) The dry powder plant materials (200 grams) are soaked in 70% ethanol at a ratio of 1:20 (mass: volume) at room temperature (23 - 27 °C) for 24 hours, and then ultrasonically extracted for 30 minutes. Then the sample is filtered;
[0068] (4) As described in (3), the solid residue is extracted two more times. The three filtrates are combined and then evaporated to dryness under vacuum to obtain the ethanol extract of Aegiceras corniculatum leaves. Part of the ethanol extract is suspended in distilled water and extracted with ethyl acetate to obtain the ethyl acetate extract of Aegiceras corniculatum leaves. Weigh a certain amount of the ethyl acetate extract in dechlorinated water and disperse (dissolve) the extract with ultrasonic waves to prepare a mother liquor with a concentration of 5 g / L;
[0069] (5) Methane determination: Add 5 cm thick paddy soil into the container. Take 20 mL, 30 mL, and 40 mL of the mother liquor respectively, and make up the volume to 500 mL with clear water to obtain ethyl acetate extracts of Aegiceras corniculatum leaves with concentrations of 0.20 g / L, 0.30 g / L, and 0.40 g / L in 500 mL. Pour them into the containers with paddy soil respectively to form a water layer of about 5 cm. The control group does not add the mother liquor of ethyl acetate extract of Aegiceras corniculatum leaves. Use the LI-7810 portable greenhouse gas analyzer to measure the change in methane emissions from the paddy soil in the container.
[0070] Compared with the control group, the methane emission rate of the soil in the container and the methane emission per cubic centimeter during the measurement period in the treatment with 0.20 g / L ethyl acetate extract of Aegiceras corniculatum leaves are as Figure 4 shown in Table 1. After calculation, the maximum methane emission rate of the control group during the measurement period is 4.09 ppbv / min, and that of the 0.20 g / L ethyl acetate extract group is 3.85 ppbv / min; the minimum methane emission rate of the control group is 3.99 ppbv / min, and the minimum methane emission rate of the 0.20 g / L ethyl acetate extract group is 3.29 ppbv / min; the average methane emission rate of the control group during the measurement period is 4.04 ppbv / min, and the average methane emission rate of the 0.20 g / L ethyl acetate extract group is 3.57 ppbv / min; the methane content per cubic centimeter of the control group is 1.111 mg, and the emission of the 0.20 g / L ethyl acetate extract group is 0.815 mg, with a 26.6% reduction in the ethyl acetate group.
[0071] Compared with the control group, 0.30 g / L ethyl acetate extract of Aegiceras corniculatum leaves can reduce methane emissions from paddy fields. The methane emission rate of the soil in the container and the methane emission per cubic centimeter during the measurement period are as Figure 4 shown in Table 1. After calculation, the maximum methane emission rate of the control group during the measurement period is 4.09 ppbv / min, and the maximum methane emission rate of the 0.30 g / L ethyl acetate extract group is 3.28 ppbv / min; the minimum methane emission rate of the control group is 3.99 ppbv / min, and the minimum methane emission rate of the 0.30 g / L ethyl acetate extract group is 2.94 ppbv / min; the average methane emission rate of the control group during the measurement period is 4.04 ppbv / min, and the average methane emission rate of the 0.30 g / L ethyl acetate extract group is 3.11 ppbv / min; the methane content per cubic centimeter of the control group is 1.111 mg, and the emission of the 0.30 g / L ethyl acetate extract group is 0.525 mg, with a 52.7% reduction in the ethyl acetate group.
[0072] Compared with the control group, the ethyl acetate extract of Aegiceras corniculatum leaves at 0.40 g / L can effectively reduce methane emissions from paddy field soil. The methane emission rate of the soil in the container and the methane emission per cubic centimeter during the measurement period are as Figure 5 shown in Table 1. After calculation, the maximum methane emission rate of the control group during the measurement period was 4.09 ppbv / min, and that of the ethyl acetate extract group was 2.07 ppbv / min; the minimum methane emission rate of the control group was 3.99 ppbv / min, and that of the ethyl acetate extract group was 2.01 ppbv / min; the average methane emission rate of the control group during the measurement period was 4.04 ppbv / min, and the average methane emission rate of the ethyl acetate extract group was 2.04 ppbv / min; the methane content per cubic centimeter of the control group was 1.111 mg, and that of the ethyl acetate extract group was 0.096 mg, with a 91% reduction in the ethyl acetate group.
[0073] Table 1 Comparison of methane production between the control group and the treatment groups with ethyl acetate extracts of Aegiceras corniculatum leaves at different concentrations
[0074]
[0075] Example 3
[0076] This example provides a method for using the ethanol extract of Aegiceras corniculatum leaves to kill Pomacea canaliculata and reduce methane emissions from paddy field soil. The specific steps include:
[0077] (1) Collect the whole Aegiceras corniculatum leaves, wash the plant materials, dry them in a ventilated place, and cut them into pieces.
[0078] (2) The cut plant materials are dried in a constant temperature forced-air drying oven at 60 °C for 24 h, crushed by a plant sample crusher, passed through a 60-mesh sieve, the dry powder sample is sealed in a plastic bag, and stored in a desiccator for later use.
[0079] (3) The dry powder plant materials (200 g) are soaked in 70% ethanol at a ratio of 1:20 (mass: volume) at room temperature (23 - 27 °C) for 24 hours, and then ultrasonically extracted for 30 minutes. Then the sample is filtered.
[0080] (4) As described in (3), the solid residue is extracted two more times. The three filtrates are combined and then evaporated to dryness under vacuum to obtain the ethanol extract of Aegiceras corniculatum leaves. Weigh a certain amount of the ethanol extract in dechlorinated water, and disperse (dissolve) the extract with ultrasonic waves to prepare a stock solution with a concentration of 5 g / L.
[0081] (5) Toxicity test: 4 mL, 5 mL, and 6 mL of the mother liquor of the ethanol extract were taken respectively and made up to 1 L to obtain ethanol extract solutions with concentrations of 0.02 g / L, 0.025 g / L, and 0.03 g / L. 10 apple snails were added to each concentration of the extract solution. After 3 days, the mortality rates of the apple snails reached 40%, 60%, and 100% respectively. After 5 days, all the apple snails died, and the mortality rates are shown in Table 2. The control group did not add the ethanol extract of Aegiceras corniculatum leaves.
[0082] Table 2 The killing effect of ethanol extracts of Aegiceras corniculatum leaves with different concentrations on apple snails
[0083]
[0084] (6) Methane determination: 5 cm thick paddy soil was added to the container. 4 mL, 5 mL, and 6 mL of the mother liquor were taken respectively and made up to 500 mL with clear water to obtain 500 mL of ethanol extracts of Aegiceras corniculatum leaves with concentrations of 0.02 g / L, 0.025 g / L, and 0.03 g / L. They were respectively poured into the containers with paddy soil to form a water layer of about 5 cm. The control group did not add the mother liquor of the ethanol extract of Aegiceras corniculatum leaves. The LI-7810 portable greenhouse gas analyzer was used to measure the change in methane emissions from the paddy soil in the container.
[0085] Compared with the control group, the methane emission rate of the soil in the container during the measurement period and the methane emission per cubic centimeter of the ethanol extract of Aegiceras corniculatum leaves at a concentration of 0.02 g / L are as Figure 6 shown in Table 3. After calculation, the maximum methane emission rate of the control group during the measurement period was 4.09 ppbv / min, and that of the ethanol extract solution group was 4.05 ppbv / min; the average methane emission rate of the control group during the measurement period was 4.04 ppbv / min, and the average methane emission rate of the ethanol extract group was 4.02 ppbv / min; the methane content per cubic centimeter of the control group was 1.111 mg, and that of the ethanol extract group was 1.103 mg, and the ethanol group decreased by 7.2%.
[0086] Compared with the control group, the ethanol extract of Aegiceras corniculatum leaves at a concentration of 0.025 g / L can reduce the methane emissions from paddy soil to a certain extent. The methane emission rate of the soil in the container during the measurement period and the methane emission per cubic centimeter are as Figure 6As shown in Table 3. Through calculation, it is obtained that the maximum methane emission rate of the control group during the measurement period was 4.09 ppbv / min, and that of the ethanol extract group was 3.87 ppbv / min; the minimum methane emission rate of the control group was 3.99 ppbv / min, and that of the ethanol extract group was 3.85 ppbv / min; the average methane emission rate of the control group during the measurement period was 4.04 ppbv / min, and the average methane emission rate of the ethanol extract group was 3.86 ppbv / min; the methane content per cubic centimeter of the control group was 1.111 mg, and that of the ethanol extract group was 0.898 mg, with a 19.2% reduction in the ethanol group.
[0087] Compared with the control group, the ethanol extract of Aegiceras corniculatum at 0.03 g / L can reduce the methane emission from paddy soil to a certain extent. The methane emission rate and the methane emission per cubic centimeter of the soil in the container during the measurement period are as Figure 6 As shown in Table 3. Through calculation, it is obtained that the maximum methane emission rate of the control group during the measurement period was 4.09 ppbv / min, and that of the ethanol extract group was 3.53 ppbv / min; the minimum methane emission rate of the control group was 3.99 ppbv / min, and that of the ethanol extract group was 3.52 ppbv / min; the average methane emission rate of the control group during the measurement period was 4.04 ppbv / min, and the average methane emission rate of the ethanol extract group was 3.53 ppbv / min; the methane content per cubic centimeter of the control group was 1.111 mg, and that of the ethanol extract group was 0.778 mg, with a 30% reduction in the ethanol group.
[0088] Table 3 Comparison of Methane Production between the Control Group and the Treatment Groups with Ethanol Extracts of Aegiceras corniculatum Leaves at Different Concentrations
[0089]
[0090] Example 4
[0091] This example provides a method for using a mixture of ethanol extract and ethyl acetate extract of Aegiceras corniculatum leaves to kill Pomacea canaliculata and reduce methane emissions. The specific steps include:
[0092] (1) Collect the whole Aegiceras corniculatum leaves, wash the plant materials clean, air-dry them in a ventilated place, and cut them into pieces.
[0093] (2) Dry the cut plant materials in a constant-temperature forced-air drying oven at 60 °C for 24 h, crush them with a plant sample crusher, pass through a 60-mesh sieve, seal the dry powder samples in plastic bags, and store them in a desiccator for later use.
[0094] (3) The dry powdery plant material (200 g) was soaked in 70% ethanol at room temperature (23 - 27 °C) at a ratio of 1:20 (mass:volume) for 24 hours, and then subjected to ultrasonic extraction for 30 minutes. Then the sample was filtered;
[0095] (4) As described in (3), the solid residue was extracted two more times. The three filtrates were combined and then evaporated to dryness under vacuum to obtain the ethanol extract of Aegiceras corniculatum leaves.
[0096] (5) The ethanol extract of Aegiceras corniculatum leaves was dissolved in water at a ratio of 3:1 and extracted with ethyl acetate. The extraction was repeated until the color of the upper ethyl acetate layer did not change. The extraction solutions were mixed, rotary evaporated, and dried to obtain the ethyl acetate extract of Aegiceras corniculatum leaves.
[0097] (6) Ethanol extract powder and ethyl acetate extract powder were taken and thoroughly mixed at a ratio of 1:15, that is, 0.025 g of ethanol extract powder and 0.375 g of ethyl acetate extract powder were mixed, 0.02 g of ethanol extract powder and 0.3 g of ethyl acetate extract powder were mixed, and 0.023 g of ethanol extract powder and 0.345 g of ethyl acetate extract powder were mixed and dissolved in 1 L of water respectively to prepare concentrations of 0.4 g / L, 0.32 g / L, and 0.368 g / L. 10 Pomacea canaliculata were added to each mixed solution. After 3 days, the mortality rate of Pomacea canaliculata could reach 100%, which was higher than the effect of adding only ethanol extract or only ethyl acetate extract. The comparison of the mortality rates is shown in Table 4.
[0098] Table 4 The killing effect of different concentrations of mixed extracts on Pomacea canaliculata
[0099]
[0100] (7) Methane determination: 5 cm thick paddy soil was added to the container. 0.16 g, 0.184 g, and 0.2 g of the mixed extract (the ratio of ethanol extract powder to ethyl acetate extract was 1:15) were taken and mixed with 500 mL of clear water respectively to obtain 500 mL of mixed extracts with concentrations of 0.32 g / L, 0.368 g / L, and 0.4 g / L. They were poured into the containers with paddy soil respectively to form a water layer of about 5 cm. The control group did not add the mixed extract. The change of methane in the container was measured using a LI-7810 portable greenhouse gas analyzer.
[0101] Compared with the control group, the mixed extract with a concentration of 0.32 g / L could effectively reduce the methane emission in the paddy field. The methane production rate and methane emission per cubic centimeter in the container during the measurement period are as Figure 7 、 Figure 8As shown. After calculation, the maximum methane emission rate of the control group during the measurement period was 4.09 ppbv / min, and that of the mixed extract group was 3.55 ppbv / min; the minimum methane emission rate of the control group was 3.99 ppbv / min, and that of the mixed extract group was 3.43 ppbv / min; the average methane emission rate of the control group during the measurement period was 4.04 ppbv / min, and the average methane emission rate of the mixed extract group was 3.49 ppbv / min; the methane content per cubic centimeter of the control group was 1.111 mg, and that of the mixed extract group was 0.87 mg, and the methane content of the latter was significantly reduced by 21.6%.
[0102] Compared with the control group, the mixed extract at 0.368 g / L can effectively reduce methane emissions from paddy soil. The methane production rate and methane emissions per cubic centimeter in the container during the measurement period are as Figure 7 、 Figure 8 shown. After calculation, the maximum methane emission rate of the control group during the measurement period was 4.09 ppbv / min, and that of the mixed extract group was 3.05 ppbv / min; the minimum methane emission rate of the control group was 3.99 ppbv / min, and that of the mixed extract group was 2.99 ppbv / min; the average methane emission rate of the control group during the measurement period was 4.04 ppbv / min, and the average methane emission rate of the mixed extract group was 3.02 ppbv / min; the methane content per cubic centimeter of the control group was 1.111 mg, and that of the mixed extract group was 0.56 mg, and the methane content of the latter was significantly reduced by 49.5%.
[0103] Compared with the control group, the mixed extract at 0.4 g / L can effectively reduce methane emissions from paddy fields. The methane production rate and methane emissions per cubic centimeter in the container during the measurement period are as Figure 7 、 Figure 8 shown. After calculation, the maximum methane emission rate of the control group during the measurement period was 4.09 ppbv / min, and that of the mixed extract group was 2.90 ppbv / min; the minimum methane emission rate of the control group was 3.99 ppbv / min, and that of the mixed extract group was 2.85 ppbv / min; the average methane emission rate of the control group during the measurement period was 4.04 ppbv / min, and the average methane emission rate of the mixed extract group was 2.87 ppbv / min; the methane content per cubic centimeter of the control group was 1.111 mg, and that of the mixed extract group was 0.45 mg, and the methane content of the latter was significantly reduced by 59.5%.
[0104] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.
Claims
1. Use of Aegiceras corniculatum extract in controlling snails and / or reducing soil methane emissions, characterized in that: The Aegiceras corniculatum extract is an extract of Aegiceras corniculatum leaves; the extract of Aegiceras corniculatum leaves is at least one of ethyl acetate extract of Aegiceras corniculatum leaves and ethanol extract of Aegiceras corniculatum leaves; When using only the ethyl acetate extract of Aegiceras corniculatum leaves, the final concentration of the ethyl acetate extract of Aegiceras corniculatum leaves is 0.20 - 0.40 g / L; When using only the ethanol extract of Aegiceras corniculatum leaves, the final concentration of the ethanol extract of Aegiceras corniculatum leaves is 0.02 - 0.035 g / L; When the ethyl acetate extract of Aegiceras corniculatum leaves and the ethanol extract of Aegiceras corniculatum leaves are mixed, the final concentration of the mixed extract is 0.30 - 0.50 g / L; the mass ratio of the ethanol extract of Aegiceras corniculatum leaves to the ethyl acetate extract of Aegiceras corniculatum leaves is 1:20 - 3:40; The preparation method of the ethyl acetate extract of Aegiceras corniculatum leaves includes the following steps: Dissolve the ethanol extract of Aegiceras corniculatum leaves in water, add ethyl acetate for extraction, repeat extraction until the color of the upper layer ethyl acetate does not change, combine the extraction solutions, rotary evaporate and dry to obtain the ethyl acetate extract of Aegiceras corniculatum leaves; The snail is Pomacea canaliculata; the soil is paddy soil.
2. The application according to claim 1, wherein: The application is as follows: (1) Application of the ethyl acetate extract of Aegiceras corniculatum leaves in inhibiting Pomacea canaliculata; and / or (2) Application of the ethanol extract of Aegiceras corniculatum leaves, the mixture of the ethyl acetate extract of Aegiceras corniculatum leaves and the ethanol extract of Aegiceras corniculatum leaves in killing Pomacea canaliculata; and / or (3) Application of the ethyl acetate extract of Aegiceras corniculatum leaves and / or the ethanol extract of Aegiceras corniculatum leaves in reducing soil methane emissions.
3. The application according to claim 1, characterized in that: The application includes the steps: Add the Aegiceras corniculatum leaf extract to the water body containing Pomacea canaliculata. When the Aegiceras corniculatum leaf extract is the ethyl acetate extract, its dosage is 0.20 - 0.40 g / L; when the Aegiceras corniculatum leaf extract is the ethanol extract, its dosage is 0.02 - 0.035 g / L; when the Aegiceras corniculatum leaf extract is a mixture of the ethyl acetate extract and the ethanol extract, its dosage is 0.30 - 0.50 g / L, and the mass ratio of the ethanol extract to the ethyl acetate extract is 1:20 - 3:
40.
4. The application according to claim 3, wherein: The water body is a paddy water body.
5. The application according to any one of claims 1 - 4, characterized in that: The preparation method of the ethanol extract of Aegiceras corniculatum leaves includes the following steps: Take Aegiceras corniculatum leaves, wash, air dry, cut into pieces, dry and crush, pass through a 30 - 70 mesh sieve to obtain Aegiceras corniculatum leaf powder; then soak with an ethanol aqueous solution, extract by ultrasonic, filter and extract the solid residue 1 - 2 more times, combine the filtrates, and dry to obtain the ethanol extract of Aegiceras corniculatum leaves.
6. The application according to claim 5, characterized in that: The mass ratio of the ethanol extract of Aegiceras corniculatum leaves to water is 2.5 - 3.5:1; The drying is drying at 55 - 65 °C for 22 - 25 hours; The mass - volume ratio of the Aegiceras corniculatum leaf powder to the ethanol aqueous solution is 1:15 - 20; The volume fraction of ethanol in the ethanol aqueous solution is 65 - 75%; The soaking time is 22 to 25 h; The soaking is carried out at room temperature, and room temperature refers to 23 to 27 °C; The ultrasonic extraction time is 25 to 36 min.