Seed coating agent and method for improving crop infection effect of arbuscular mycorrhizal fungi

Abstract

The invention relates to the technical field of bioremediation of arbuscular mycorrhiza, in particular to a seed coating agent and a method for improving the effect of infecting crops by arbuscular mycorrhizal fungi. The invention provides a seed coating agent for improving the effect of infecting crops by arbuscular mycorrhizal fungi. The seed coating agent is prepared from the following components: an arbuscular mycorrhizal fungi fungicide, straw compost, a water-retaining agent, chitosan oligosaccharide, an adhesive and a film-forming agent, the seed coating agent is mixed with seeds to obtain seed pills, and the seed pills are cultured for 50-70 minutes. The method can effectively improve the effect that the arbuscular mycorrhizal fungi infect crops, the dosage of the arbuscular mycorrhizal fungi is small, the process is simple, and operation is easy.

Description

Technical Field

[0001] The invention relates to the technical field of arbuscular mycorrhizal bioremediation, and in particular to a seed coating agent and a method for improving the effect of arbuscular mycorrhizal fungi infecting crops. Background Art

[0002] In recent years, due to industrial, mining, agricultural activities, etc., a large number of heavy metal ions have entered the environment, and the pollution of heavy metals in soil has become increasingly serious. These heavy metals are accompanied by physical, chemical and biological processes such as leaching and adsorption in the soil, and migrate to crops through the soil-plant system, causing physiological dysfunction and nutritional imbalance in crops, thereby affecting the growth, yield and quality of crops, and can enter the human body through the food chain, which has great potential hazards and seriously endangers human health and life safety.

[0003] Arbuscular mycorrhizal fungi (AMF) are a very important type of mycorrhizal fungi in nature, and plants that coexist with AMF are very extensive. Nearly 90% of plants in nature can form a symbiotic relationship with arbuscular mycorrhizal fungi (AMF). Studies have shown that AMF can enhance the host plant's resistance to heavy metal stress by regulating the absorption and transport of heavy metals by plants. AMF can penetrate the plant wall and enter the cortical cells of the plant to synthesize the periphyton membrane (PAM). AMF and plants exchange substances at this interface. The other end of the fungal hyphae will grow into the gap that the roots cannot reach, indirectly increasing the contact area between the roots and the soil, promoting the absorption of essential elements for plants, improving the nutritional status of plants, and improving resistance to external adverse factors. The glomalin produced by its mycelium has the function of "super glue", which is 3 to 10 times stronger than other soil carbohydrates in adhering to soil particles. At present, the application of AMF in plants mainly adopts the method of mixing appropriate amount of microorganisms into the seedling medium to cultivate mycorrhizal seedlings, and then transplanting normally, and applying appropriate amount of microorganisms in holes or strips during sowing; this method has the problems of large amount of AMF, high cost, low infection intensity and richness of arbuscules. Therefore, it is of great significance to find an AMF infection method with high infection rate (intensity) and low cost to improve the application of AMF in agriculture. Summary of the invention

[0004] The object of the present invention is to provide a seed coating agent and method for improving the effect of arbuscular mycorrhizal fungi infecting crops. The method can effectively improve the effect of arbuscular mycorrhizal fungi infecting crops, and the amount of arbuscular mycorrhizal fungi used is small, the process is simple, and the operation is easy.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The invention provides a seed coating agent for improving the effect of arbuscular mycorrhizal fungi infecting crops, comprising the following components: arbuscular mycorrhizal fungi agent, straw compost, water retaining agent, chitosan oligosaccharide, adhesive and film-forming agent;

[0007] The mass ratio of chitosan oligosaccharide to arbuscular mycorrhizal fungi agent is 1:20-40;

[0008] The mass ratio of chitosan oligosaccharide to straw compost is 1:112-132;

[0009] The mass ratio of chitosan oligosaccharide to water retaining agent is 1:2-6;

[0010] The mass volume ratio of chitosan oligosaccharide and adhesive is 1g:33-53mL;

[0011] The mass volume ratio of chitosan oligosaccharide and film-forming agent is 1g:30-50mL.

[0012] Preferably, the effective fungus species in the arbuscular mycorrhizal fungal agent is Heterosporangium heteromorphum; and the number of propagules of the arbuscular mycorrhizal fungal agent is ≥70 / g.

[0013] Preferably, the method for preparing straw compost comprises the following steps:

[0014] 1) mixing straw with fermentation bacteria, cornmeal, urea and superphosphate to obtain a mixed material;

[0015] 2) adjusting the water content of the mixed material to 50-70%, stacking and fermenting to obtain a fermentation product;

[0016] 3) airing the fermentation product until the water content is 10-20% to obtain straw compost;

[0017] The fermentation agent is BFA fermentation agent; the mass ratio of the straw to the fermentation agent is 250-1000:1; the mass ratio of the straw to urea is 60-200:1; the mass ratio of the straw to superphosphate is 6-20:1; the mass ratio of the straw to cornmeal is 25-100:0.8-1.2.

[0018] Preferably, the adhesive uses water as solvent and includes components in the following concentrations: 20-80 g / L polyvinyl alcohol and 5-15 g / L sodium carboxymethyl cellulose.

[0019] Preferably, the film-forming agent uses water as solvent and includes components in the following concentrations: 30-90 g / L polyvinyl alcohol, 10-30 g / L sodium carboxymethyl cellulose, and 10-30 g / L talc.

[0020] The present invention also provides a method for improving the effect of arbuscular mycorrhizal fungi infecting crops, comprising the following steps:

[0021] (1) mixing seeds and a seed coating agent to obtain seed pellets;

[0022] (2) Incubate the pellets for 50 to 70 minutes;

[0023] The seed coating agent is the seed coating agent described above.

[0024] Preferably, in step (2), the culture temperature is 25-35°C.

[0025] Beneficial effects of the present invention:

[0026] The invention provides a seed coating agent for improving the effect of arbuscular mycorrhizal fungi infecting crops. The seed coating agent consists of an arbuscular mycorrhizal fungi agent, straw compost, a water retaining agent, chitosan oligosaccharide, an adhesive and a film-forming agent. The seed coating agent is used to treat seeds, so the infection effect of the arbuscular mycorrhizal fungi agent can be significantly improved. The arbuscular mycorrhizal fungi agent is used in a smaller amount than in a conventional infection method, thus saving costs, and having a simple process and being easy to operate. The method can be used for the cultivation of plants in contaminated soil and the planting of crops in agricultural risk soil. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a standard chart for infestation grading;

[0028] Figure 2 It is the criterion for the richness of branches;

[0029] Figure 3 This is the microscopic morphology of wheat root infection;

[0030] Figure 4 It is the microscopic morphology of sorghum root infection. DETAILED DESCRIPTION

[0031] The invention provides a seed coating agent for improving the effect of arbuscular mycorrhizal fungi infecting crops, comprising the following components: arbuscular mycorrhizal fungi agent, straw compost, water retaining agent, chitosan oligosaccharide, adhesive and film-forming agent;

[0032] The mass ratio of chitosan oligosaccharide to arbuscular mycorrhizal fungi agent is 1:20-40, preferably 1:25-35, and more preferably 1:30;

[0033] The mass ratio of chitosan oligosaccharide to straw compost is 1:112-132, preferably 1:117-127, and more preferably 1:122;

[0034] The mass ratio of chitosan oligosaccharide to water retaining agent is 1:2-6, preferably 1:3-5, and more preferably 1:4;

[0035] The mass volume ratio of chitosan oligosaccharide to adhesive is 1g:33-53mL, preferably 1g:38-48mL, and more preferably 1g:43mL;

[0036] The mass volume ratio of chitosan oligosaccharide to the film-forming agent is 1 g:30-50 mL, preferably 1 g:35-45 mL, and more preferably 1 g:40 mL.

[0037] In the present invention, the effective fungus species in the arbuscular mycorrhizal fungal agent is Heteromorpha rhizosporon; the number of propagules of the arbuscular mycorrhizal fungal agent is ≥70 pieces / g, preferably 75 to 85 pieces / g, and more preferably 80 pieces / g.

[0038] In the present invention, the method for preparing straw compost comprises the following steps:

[0039] 1) mixing straw with fermentation bacteria, cornmeal, urea and superphosphate to obtain a mixed material;

[0040] 2) adjusting the water content of the mixed material to 50-70%, stacking and fermenting to obtain a fermentation product;

[0041] 3) airing the fermentation product until the water content is 10-20% to obtain straw compost;

[0042] In step 1), the length of the straw is 2 to 5 cm, preferably 3 cm; the straw is corn straw; the fermentation agent is BFA fermentation agent; the mass ratio of the straw to the fermentation agent is 250 to 1000:1; preferably 500 to 750:1, and more preferably 625:1; the mass ratio of the straw to urea is 60 to 200:1, preferably 100 to 160:1, and more preferably 130:1; the mass ratio of the straw to superphosphate is 6 to 20:1, preferably 10 to 16:1, and more preferably 13:1; the mass ratio of the straw to cornmeal is 25 to 100:0.8 to 1.2, preferably 50 to 75:0.9 to 1.1, and more preferably 62.5:1;

[0043] In step 2), the specific steps of the pile fermentation are: after the mixed material is mixed and fermented at 55-65° C. for 9-11 days, the pile is turned for the first time, and after fermentation for another 9-11 days, the pile is turned for the second time, and when the temperature is 35-45° C., a fermentation product is obtained;

[0044] Preferably, the mixed material is mixed and fermented at 60°C for 10 days, and then the compost is turned for the first time. After another 10 days of fermentation, the compost is turned for the second time, and a fermentation product is obtained when the temperature is 40°C.

[0045] The water content of the mixed material is preferably 60%;

[0046] The moisture content of the drying in step 3) is preferably 15%;

[0047] In the present invention, the preparation method of the water-retaining agent comprises the following steps:

[0048] (1) Mix straw compost, dimethyl sulfoxide and catalyst and let stand for 5 to 15 minutes, filter and collect the residue;

[0049] (2) mixing the filter residue and the alkaline solution, and shaking to obtain reinforced compost;

[0050] (3) activating the fortified compost in a water bath to obtain activated fortified compost;

[0051] (4) mixing the activated fortified compost with neutralized acrylic acid, acrylamide, an initiator, and N,N'-methylenebisacrylamide, and heating for 25 to 35 minutes to obtain a black colloid;

[0052] (5) ultrasonically cleaning the black colloid and drying it to obtain a water-retaining agent;

[0053] The catalyst is a potassium hydroxide aqueous solution with a mass concentration of 1 to 3%, preferably 2%;

[0054] The alkaline solution is a potassium hydroxide aqueous solution with a mass concentration of 0.5-3%, preferably 1.5-2%, and more preferably 1.75%;

[0055] The initiator is a mixture of potassium persulfate and sodium thiosulfate; the mass ratio of potassium persulfate to sodium thiosulfate is 2-5:1-3, preferably 3.5:2;

[0056] The preparation method of the neutralized acrylic acid comprises: mixing acrylic acid and potassium hydroxide aqueous solution in an ice water bath to obtain neutralized acrylic acid;

[0057] The mass concentration of the potassium hydroxide aqueous solution is 8-12%, preferably 10%;

[0058] The volume ratio of the acrylic acid to the potassium hydroxide aqueous solution is 1-3:3-7, preferably 2:5.

[0059] In the present invention, the standing time in step (1) is preferably 9 to 11 minutes, more preferably 10 minutes;

[0060] The oscillation temperature is 25 to 35°C, preferably 29 to 31°C, and more preferably 30°C; the oscillation time is 15 to 25 minutes, preferably 19 to 21 minutes, and more preferably 20 minutes;

[0061] The water bath activation temperature is 65-85°C, preferably 70-80°C, more preferably 75°C, and the water bath activation time is 30-60min, preferably 40-50min, more preferably 45min;

[0062] The heating is water bath heating; the heating temperature is 70-90°C, preferably 78-82°C, and more preferably 80°C; the heating time is preferably 30 minutes.

[0063] The drying temperature is 40-60°C, preferably 45-55°C, and more preferably 50°C.

[0064] In the present invention, the mass volume ratio of the straw compost and dimethyl sulfoxide is 1-3 g: 3-7 mL, preferably 2 g: 5 mL;

[0065] The mass volume ratio of the straw compost and the catalyst is 1-3 g: 20-30 mL, preferably 2 g: 25 mL;

[0066] The mass volume ratio of the straw compost and the alkaline solution is 1-3 g:40-60 mL, preferably 2 g:50 mL;

[0067] The mass volume ratio of the straw compost and the neutralized acrylic acid is 1-3 g: 2-11 mL, preferably 2 g: 6.5 mL;

[0068] The mass ratio of the straw compost to acrylamide is 1-3:0.5-5.0, preferably 2:2.75;

[0069] The mass ratio of the straw compost to the initiator is 1-3:0.22-0.42, preferably 2:0.32;

[0070] The mass ratio of the straw compost to N,N'-methylenebisacrylamide is 1-3:0.01-0.09, preferably 2:0.05.

[0071] In the present invention, the adhesive uses water as solvent and includes the following components in mass concentration:

[0072] Polyvinyl alcohol 20 to 80 g / L, preferably 30 to 60 g / L, more preferably 40 g / L,

[0073] Sodium carboxymethyl cellulose: 5 to 15 g / L, preferably 8 to 12 g / L, more preferably 10 g / L.

[0074] In the present invention, the film-forming agent uses water as a solvent and includes the following components in mass concentrations:

[0075] Polyvinyl alcohol 30 to 90 g / L, preferably 50 to 70 g / L, more preferably 60 g / L,

[0076] Sodium carboxymethyl cellulose 10-30 g / L, preferably 15-25 g / L, more preferably 20 g / L,

[0077] The content of talc is 10 to 30 g / L, preferably 15 to 25 g / L, and more preferably 20 g / L.

[0078] The present invention also provides a method for improving the effect of arbuscular mycorrhizal fungi infecting crops, comprising the following steps:

[0079] (1) mixing seeds and a seed coating agent to obtain seed pellets;

[0080] (2) Incubate the pellets for 50 to 70 minutes;

[0081] The seed coating agent is the seed coating agent described above.

[0082] In the present invention, before the seeds and the seed coating agent are mixed, the seeds need to be processed, and the specific steps are as follows:

[0083] After soaking the seeds in water for 2 hours, wrap them with a wet cloth, transfer them to a white porcelain plate, and incubate them at a temperature of 20-30°C and a humidity of 70-80% for 24-48 hours, turning the seeds every 12 hours;

[0084] The culture temperature is preferably 23-27°C, more preferably 25°C; the culture humidity is preferably 73-77%, more preferably 75%; the culture time is preferably 32-42h, more preferably 36h;

[0085] The specific steps of mixing the seeds and the seed coating agent are as follows: crushing the water retaining agent and straw compost to 200 meshes, stirring and mixing with seeds, arbuscular mycorrhizal fungi, chitosan oligosaccharide, indole fresh fat and adhesive, and adding a film-forming agent after pelleting to obtain seed pellets.

[0086] In the present invention, in step (2), the culture temperature is 25 to 35°C, preferably 28 to 32°C, and more preferably 30°C.

[0087] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0088] In the embodiments and comparative examples of the present invention, the arbuscular mycorrhizal fungal agent was purchased from Beijing Jinbilai Biotechnology Co., Ltd., chitosan oligosaccharide was purchased from Shandong Hailongyuan Biotechnology Co., Ltd., indole fresh fat was purchased from Zhengzhou Dehua Xinlu Pesticide Co., Ltd., and BFA fermentation agent was purchased from Fujian Oasis Biochemical Co., Ltd.

[0089] Example 1

[0090] Preparation of straw compost: 300 kg of corn straw is dried and crushed into segments with a length of 2 cm, 1.2 kg of BFA fermentation agent, 14.4 kg of cornmeal, 5 kg of urea, and 30 kg of superphosphate are added, and mixed to obtain a mixed material; the moisture content of the mixed material is adjusted to 55%, and it is piled into strips, and the surface is covered with a nano-biocompost film, and after mixed fermentation at 60° C. for 10 days, the first composting is carried out, and after fermentation for another 10 days, the second composting is carried out, and when the temperature is 40° C., a fermentation product is obtained; the fermentation product is aired until the moisture content is 17% to obtain straw compost.

[0091] Preparation of neutralized acrylic acid: 4 mL of acrylic acid and 13.6 mL of 12% potassium hydroxide aqueous solution were mixed and allowed to stand in an ice water bath for 20 min to obtain neutralized acrylic acid.

[0092] Preparation method of initiator: Potassium persulfate and sodium thiosulfate are mixed in a mass ratio of 3:1 to prepare an initiator.

[0093] The preparation of water retaining agent includes:

[0094] (1) 3 g of straw compost, 6 mL of dimethyl sulfoxide, and 30 mL of 2% potassium hydroxide aqueous solution were mixed and allowed to stand for 12 min, and then filtered to obtain the residue;

[0095] (2) Add 165 mL of 2.46% potassium hydroxide aqueous solution to the filter residue and shake at 25° C. for 25 min to obtain enhanced compost.

[0096] (3) activating the fortified compost in a water bath at 85° C. for 48.8 min to obtain activated fortified compost;

[0097] (4) The activated fortified compost was mixed with 26.4 mL of neutralized acrylic acid, 4.47 g of acrylamide, 0.78 g of initiator, and 0.06 g of N,N'-methylenebisacrylamide, and heated in a water bath at 90 °C for 25 min to obtain a black colloid;

[0098] (5) The black colloid is ultrasonically cleaned at 30° C. for 5 min and dried at 60° C. to obtain a water-retaining agent.

[0099] Preparation of adhesive: 6 g of polyvinyl alcohol and 1 g of sodium carboxymethyl cellulose were dissolved in water and the volume was fixed to 100 mL to obtain an adhesive.

[0100] Preparation of the film-forming agent: 5 g of polyvinyl alcohol, 2 g of sodium carboxymethyl cellulose and 2 g of talc were dissolved in water and the volume was fixed to 100 mL to obtain a film-forming agent.

[0101] A method for improving the effect of arbuscular mycorrhizal fungi infecting crops:

[0102] (1) After soaking the seeds in water for 2 hours, wrap them with a wet cloth, transfer them to a white porcelain plate, place them in an incubator at 25° C. and 75% humidity for 48 hours, and turn the seeds every 12 hours to obtain seeds to be treated; 100 g of the seeds to be treated, 15 g of arbuscular mycorrhizal fungi agent (the number of propagules is 80 / g), 2 g of water retaining agent (crushed to 200 mesh), 61 g of straw compost (crushed to 200 mesh), 0.5 g of chitosan oligosaccharide, and 21.5 mL of adhesive are stirred and mixed, and after the mixture is pelleted, 20 mL of film-forming agent is added to wrap the pellets;

[0103] (2) Place the seed pellets in an incubator at 30°C for 1 hour.

[0104] Comparative Example 1

[0105] The preparation steps of straw compost, adhesive and film-forming agent are the same as those in Example 1;

[0106] A method for improving the effect of arbuscular mycorrhizal fungi infecting crops:

[0107] 1) After soaking the seeds in water for 2 hours, wrap them with a wet cloth, transfer them to a white porcelain plate, and place them in an incubator at 25°C and 75% humidity for 48 hours, turning the seeds every 12 hours; 100g of seeds and 15g of arbuscular mycorrhizal fungi agent (the number of propagules is 80 / g), 63.5g of straw compost (crushed to 200 mesh), and 21.5mL of adhesive are stirred and mixed, and after forming pellets, 20mL of film-forming agent is added to wrap the pellets;

[0108] (2) Place the seed pellets in an incubator at 30°C for 1 hour.

[0109] Comparative Example 2

[0110] The preparation steps of straw compost, water retaining agent, adhesive and film forming agent are the same as those in Example 1;

[0111] (1) After soaking the seeds in water for 2 h, wrap them with a wet cloth, transfer them to a white porcelain plate, and place them in an incubator at 25°C and 75% humidity for 48 h, turning the seeds every 12 h; 100 g of seeds and 15 g of arbuscular mycorrhizal fungi agent (the number of propagules is 80 / g), 2 g of water retaining agent (crushed to 200 mesh), 61.5 g of straw compost (crushed to 200 mesh), and 21.5 mL of adhesive were stirred and mixed, and then 20 mL of film-forming agent was added to form pellets to wrap the pellets;

[0112] (2) Place the seed pellets in an incubator at 30°C for 1 hour.

[0113] Comparative Example 3

[0114] The preparation steps of straw compost, water retaining agent, adhesive and film forming agent are the same as those in Example 1;

[0115] A method for improving the effect of arbuscular mycorrhizal fungi infecting crops:

[0116] (1) After soaking the seeds in water for 2 h, wrap them with a wet cloth, transfer them to a white porcelain plate, and place them in an incubator at 25°C and 75% humidity for 48 h, turning the seeds every 12 h; 100 g of seeds and 15 g of arbuscular mycorrhizal fungi agent (the number of propagules is 80 / g), 2 g of water retaining agent (crushed to 200 mesh), 60 g of straw compost (crushed to 200 mesh), 0.5 g of chitosan oligosaccharide, 1 mL of indole ester, and 21.5 mL of adhesive were stirred and mixed, and then 20 mL of film-forming agent was added to form pellets to wrap the pellets;

[0117] (2) Place the seed pellets in an incubator at 30°C for 1 hour.

[0118] Experimental Example 1

[0119] The experiment was conducted in the Xichang University Innovation and Entrepreneurship Greenhouse Planting Base, using pots with a diameter of 15 cm and a height of 12.5 cm as cultivation containers (a tray was placed at the bottom to prevent nutrient loss);

[0120] Uncontaminated soil: Soil was collected from the forest land on the campus of Xichang University, placed in a ventilated place, and naturally dried before being passed through a 20-mesh sieve. Its physical and chemical properties are as follows: pH 8.55, organic matter 15.38 g / kg, total nitrogen 0.77 g / kg, alkaline nitrogen 39.30 mg / kg, total phosphorus 0.42 g / kg, available phosphorus 12.07 mg / kg, total potassium 19.0 g / kg, available potassium 71 mg / kg, and cadmium 0.76 mg / kg;

[0121] 10mg / kg cadmium contaminated soil: 10mg / kg cadmium (using CdCl2·2.5H2O) was added to the uncontaminated soil at one time for soil aging treatment. After aging for two weeks, cadmium contaminated soil was obtained;

[0122] 100g of wheat seeds were treated by the methods described in Example 1 and Comparative Examples 1 to 3, respectively. 2kg of soil was added to each pot before sowing. A total of 10 treatments were set up in the experiment, A0, B0, C0, D0, and E0 were respectively sown in uncontaminated soil with wheat seeds that were not coated, wheat seeds treated by the method described in Example 1, wheat seeds treated by the method described in Comparative Example 1, wheat seeds treated by the method described in Comparative Example 2, and wheat seeds treated by the method described in Comparative Example 3; A10 , B 10 , C 10 , D 10 、E 10 In 10 mg / kg cadmium contaminated soil, wheat seeds that have not been coated, wheat seeds that have been treated by the method described in Example 1, wheat seeds that have been treated by the method described in Comparative Example 1, wheat seeds that have been treated by the method described in Comparative Example 2, and wheat seeds that have been treated by the method described in Comparative Example 3 are sown respectively; A0, A 10 The traditional infection method (2g mycorrhizal fungi were applied directly next to the seeds) was used, and 2g of Heteromorpha rhizosporium was added to each pot by hole application. Watering was carried out regularly during the planting period to ensure the normal growth and development of the crops. After 30 days of greenhouse cultivation, the pots of each treatment were brought back to the laboratory for relevant testing;

[0123] Five seedlings were selected from each treatment, and the roots were washed with pure water and cut into 1 cm root segments. The method of Trouvelot et al. (Trouvelot A, Kough JL, Gianinazzi-Pearson V. Measurement of demycorrhiz ation V A d'unsystème radiculaire. Recherched e thods d'estimation ayantune signification fonctionelle. In: Physiological and Genetic Aspects of Mycorrhiza e. Paris: INR Press, 1986: 217-221) was used, and the roots were transparentized with 10% (w / v) potassium hydroxide, bleached with 10% hydrogen peroxide, acidified with 2% HCl, stained with lactic acid phenol cotton blue dye, and observed under a microscope for AMF infection (such as Figure 3 As shown), and calculated F% (frequency of mycorrhizal infection), M% (intensity of root infection), m% (intensity of mycorrhizal formation), a% (infection arbuscular abundance) and A% (root arbuscular abundance), the results are shown in Tables 1-2;

[0124] Among them, mycorrhizal infection frequency F% = (number of infected root segments / total number of root segments) × 100%;

[0125] Root infection intensity M% = (95×n5+70×n4+30×n3+5×n2+n1) / (total number of root segments)% (where n5 represents the number of root segments with level 5 infection; n4 represents the number of root segments with level 4 infection, n3 represents the number of root segments with level 3 infection, n2 represents the number of root segments with level 2 infection, and n1 represents the number of root segments with level 1 infection. The infection classification standards are as follows: Figure 1 shown);

[0126] m%=M×(number of total root segments) / (number of infected root segments)%;

[0127] Abundance of infected root segments a% = (100 × mA3 + 50 × mA2 + 10 × mA1) / 100 (where mA3 = [(95 × n5 × A3 + 70 × n4 × A3 + 30 × n3 × A3 + 5 × n2 × A3 + n1 × A3) / (number of infected root segments)] × 100 / m, mA2 = [(95 × n5 × A2 + 70 × n4 × A2 + 30 × n3 × A2 + 5 × n2×A2+n1×A2) / (number of infected root segments)]×100 / m, mA1=[(95×n5×A1+70×n4×A1+30×n3×A1+5×n2×A1+n1×A1) / (number of infected root segments)]×100 / m; A3 is the number of root segments with abundant arbuscules, A2 is the number of root segments with more arbuscules, and A1 is the number of root segments with few arbuscules. The criteria for the richness of arbuscules are as follows: Figure 2 shown);

[0128] Root arbuscular abundance A% = a% × (M / 100).

[0129] Table 1 Mycorrhizal infection degree of wheat in uncontaminated soil

[0130] deal with Infection frequency F(%) Infection intensity M(%) Arbuscular abundance A(%) <![CDATA[A0]]> <![CDATA[80.41±2.64 c ]]> <![CDATA[2.83±0.69 d ]]> <![CDATA[5.98±1.49 e ]]> <![CDATA[B0]]> <![CDATA[98.89±1.09 a ]]> <![CDATA[18.37±4.096 a ]]> <![CDATA[38.5±4.06 a ]]> <![CDATA[C0]]> <![CDATA[91.11±2.81 b ]]> <![CDATA[7.09±0.593 c ]]> <![CDATA[12.68±0.64 d ]]> <![CDATA[D0]]> <![CDATA[92.22±1.48 b ]]> <![CDATA[7.92±0.925 c ]]> <![CDATA[16.2±2.75 c ]]> <![CDATA[E0]]> <![CDATA[94.44±1.93 ab ]]> <![CDATA[9.61±0.019 b ]]> <![CDATA[21.08±4.37 b ]]>

[0131] Table 2 Degree of mycorrhizal infection of wheat in 10 mg / kg cadmium contaminated soil

[0132]

[0133]

[0134] from Figure 3 It can be seen that compared with the traditional infection methods A0 and A 10 Compared with the wheat seed coating treatments B0, C0, D0, E0, B 10 , C 10 , D 10 、E 10 The mycelium in the roots of the treatment increased, among which B0 and B 10 treatment, the hyphae in the roots were denser and had obvious vesicles;

[0135] It can be seen from Tables 1 and 2 that the frequency F%, infection intensity M%, and arbuscular abundance A% of mycorrhizal fungi infecting wheat roots under heavy metal stress decreased; compared with A0, A 10The infection frequency F%, infection intensity M%, and arbuscular abundance A% of the seed coating treatments were reduced by 12.1%, 26.1%, and 28.3%, respectively. Compared with A0, the seed coating treatments B0, C0, D0, and E0 significantly increased the values ​​of F%, M%, and A%, especially B0. Compared with A0, the values ​​of F%, M%, and A% of B0 treatment increased by 23.0%, 549.1%, and 543.8%, respectively. Compared with A0, the values ​​of F%, M%, and A% of B0 treatment increased by 23.0%, 549.1%, and 543.8%, respectively. 10 Compared with the seed coating treatment B 10 , C 10 , D 10 、E 10 Significantly improved the values ​​of F%, M%, and A%, especially B 10 The largest increase; 10 In comparison, B 10 The values ​​of treatment F%, M%, and A% increased by 33.5%, 564.6%, and 511.2%, respectively;

[0136] Therefore, B0 and B 10 After coating treatment, the infection rate, infection intensity and arbuscular abundance of Heterosporium heterocystis on wheat roots were increased; the coating agent and method described in Example 1 had the best infection effect on wheat roots.

[0137] Experimental Example 2

[0138] 100 g of sorghum seeds were treated with the methods described in Example 1 and Comparative Examples 1 to 3, respectively. Referring to the method described in Experimental Example 1, the AMF infection was observed (eg Figure 4 As shown), and calculated F% (frequency of mycorrhizal infection), M% (intensity of root infection), m% (intensity of mycorrhizal formation), a% (infection arbuscular abundance) and A% (root arbuscular abundance). The results are shown in Tables 3-4.

[0139] Table 3. Mycorrhizal infection degree of sorghum in uncontaminated soil

[0140] deal with Infection frequency F(%) Infection intensity M(%) Arbuscular abundance A(%) A0 <![CDATA[67.02±1.86 d ]]> <![CDATA[1.48±0.89 d ]]> <![CDATA[4.11±1.54 d ]]> <![CDATA[B0]]> <![CDATA[95.83±1.54 a ]]> <![CDATA[6.46±0.41 a ]]> <![CDATA[20.38±4.74 a ]]> <![CDATA[C0]]> <![CDATA[82.72±4.69 c ]]> <![CDATA[2.14±0.67b cd ]]> <![CDATA[5.94±1.22 cd ]]> <![CDATA[D0]]> <![CDATA[88.89±3.85 bc ]]> <![CDATA[3.33±0.86 bc ]]> 7.57±2.35c <![CDATA[E0]]> <![CDATA[92.43±3.25 ab ]]> 4.02±0.68b <![CDATA[11.08±2.03 b ]]>

[0141] Table 4. Infection degree of sorghum mycorrhiza in 10 mg / kg cadmium-contaminated soil

[0142] deal with Infection frequency F(%) Infection intensity M(%) Arbuscular abundance A(%) <![CDATA[A 10 ]]> <![CDATA[59.03±2.27 d ]]> <![CDATA[1.02±0.38 c ]]> <![CDATA[3.31±1.03 d ]]> <![CDATA[B 10 ]]> <![CDATA[91.11±1.92 a ]]> <![CDATA[5.68±0.15 a ]]> <![CDATA[13.15±3.65 a ]]> <![CDATA[C 10 ]]> <![CDATA[77.49±8.25 c ]]> <![CDATA[1.69±0.83 c ]]> <![CDATA[4.88±0.62 cd ]]> <![CDATA[D 10 ]]> <![CDATA[83.08±4.34 bc ]]> <![CDATA[3.61±0.45 b ]]> <![CDATA[5.74±1.19 bc ]]> <![CDATA[E 10 ]]> <![CDATA[86.38±3.37 b ]]> <![CDATA[4.81±0.66 ab ]]> <![CDATA[7.33±2.52 b ]]>

[0143] from Figure 4 It can be seen that the traditional infection methods A0 and A 10 Compared with the control group, the sorghum seed coating treatments B0, C0, D0, E0, B 10 , C 10 , D 10 、E 10 The mycelium in the roots of the treatment increased, among which B0 and B 10 treatment, the hyphae in the roots were denser;

[0144] It can be seen from Tables 3 and 4 that the F%, M%, and A% of mycorrhizal fungi on sorghum roots decreased under heavy metal stress. 10 The infection frequency F%, infection intensity M%, and arbuscular abundance A% of the seed coating treatments were reduced by 11.9%, 31.1%, and 19.5%, respectively. Compared with A0, the seed coating treatments B0, C0, D0, and E0 significantly increased the values ​​of F%, M%, and A%, especially B0. Compared with A0, the values ​​of F%, M%, and A% of B0 treatment increased by 43.0%, 336.5%, and 395.9%, respectively. Compared with A0, the values ​​of F%, M%, and A% of B0 treatment increased by 43.0%, 336.5%, and 395.9%, respectively. 10 Compared with the seed coating treatment B 10 , C 10 , D 10 、E 10 Significantly improved the values ​​of F%, M%, and A%, especially B 10 The largest increase; 10 In comparison, B 10 The values ​​of treatment F%, M%, and A% increased by 54.3%, 456.9%, and 297.3%, respectively;

[0145] Therefore, B0 and B 10 After coating treatment, the infection rate, infection intensity and arbuscular abundance of Heterosporium heterocystis on sorghum roots increased. The coating agent and method described in Example 1 had the best infection effect on sorghum roots.

[0146] It can be seen from the above embodiments that the present invention provides a seed coating agent and method for improving the effect of arbuscular mycorrhizal fungi infecting crops. The method can effectively improve the effect of arbuscular mycorrhizal fungi infecting crops, and the amount of arbuscular mycorrhizal fungi used is small, the process is simple, and the operation is easy.

[0147] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A seed coating agent for improving the effect of arbuscular mycorrhizal fungi infecting crops, characterized in that: The invention comprises the following components: arbuscular mycorrhizal fungi agent, straw compost, water retaining agent, chitosan oligosaccharide, adhesive and film-forming agent; The mass ratio of chitosan oligosaccharide to arbuscular mycorrhizal fungi agent is 1:20-40; The mass ratio of chitosan oligosaccharide to straw compost is 1:112-132; The mass ratio of chitosan oligosaccharide to water retaining agent is 1:2-6; The mass volume ratio of chitosan oligosaccharide and adhesive is 1g:33-53mL; The mass volume ratio of chitosan oligosaccharide and film-forming agent is 1g:30-50mL.

2. The seed coating agent according to claim 1, characterized in that The effective fungus species in the arbuscular mycorrhizal fungal agent is Heteromorpha rhizosporon; the number of propagules of the arbuscular mycorrhizal fungal agent is ≥70 / g.

3. The seed coating agent according to claim 2, characterized in that The preparation method of the straw compost comprises the following steps: 1) mixing straw with fermentation bacteria, cornmeal, urea and superphosphate to obtain a mixed material; 2) adjusting the water content of the mixed material to 50-70%, stacking and fermenting to obtain a fermentation product; 3) Air-drying the fermentation product until the water content is 10-20% to obtain straw compost.

4. The seed coating agent according to claim 3, characterized in that The fermentation agent is BFA fermentation agent; the mass ratio of the straw to the fermentation agent is 250-1000:1; the mass ratio of the straw to urea is 60-200:1; the mass ratio of the straw to superphosphate is 6-20:1; the mass ratio of the straw to cornmeal is 25-100:0.8-1.

2.

5. The seed coating agent according to claim 4, characterized in that The adhesive uses water as solvent and comprises components with the following concentrations: 20-80 g / L polyvinyl alcohol and 5-15 g / L sodium carboxymethyl cellulose.

6. The seed coating agent according to claim 5, characterized in that The film-forming agent uses water as solvent and comprises components with the following concentrations: 30-90 g / L polyvinyl alcohol, 10-30 g / L sodium carboxymethyl cellulose, and 10-30 g / L talc.

7. A method for improving the effect of arbuscular mycorrhizal fungi infecting crops, characterized in that: The steps include: (1) mixing seeds and a seed coating agent to obtain seed pellets; (2) Incubate the pellets for 50 to 70 minutes; The seed coating agent is the seed coating agent according to any one of claims 1 to 6.

8. The method according to claim 7, characterized in that In step (2), the culture temperature is 25-35°C.

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