Corn drought-resisting and yield-increasing method based on synergistic effect of arbuscular mycorrhizal fungi and calcium silicate

Abstract

The invention discloses a corn drought resisting and yield increasing method based on the synergistic effect of arbuscular mycorrhizal fungi and calcium silicate, and belongs to the technical field of biology. According to the corn drought-resisting and yield-increasing method based on the synergistic effect of the arbuscular mycorrhizal fungi and the calcium silicate, the absorption area of a corn root system is increased by utilizing a hypha network formed by the arbuscular mycorrhizal fungi and the root system, and the colonization rate of the arbuscular mycorrhizal fungi in the corn root system is increased by combining the effect of the calcium silicate; therefore, photosynthesis, nutrient absorption and water utilization efficiency of plants are further improved, growth and development of corn under drought stress are relieved, and finally the yield of corn is increased.

Description

Technical Field

[0001] This invention relates to the field of biotechnology, and more specifically to a method for increasing corn yield and drought resistance based on the synergistic effect of arbuscular mycorrhizal fungi and calcium silicate. Background Technology

[0002] With global warming, the impact of drought on agricultural production is becoming increasingly prominent. Drought stress is one of the important abiotic stress factors limiting global crop growth and productivity, significantly negatively impacting crop yield and quality. Under drought stress, plants often experience leaf wilting, flower and fruit drop, and in severe cases, even plant death. Statistics show that 36% of the world's land area and 43.9% of arable land are currently experiencing drought or semi-arid conditions. With the rapid development of global industry and agriculture, water consumption has increased dramatically. Coupled with population growth and frequent human activities leading to severe water pollution, global droughts are becoming more frequent.

[0003] Maize (Zea mays L.) is one of the most widely cultivated crops globally and is an extremely important food, feed, and economic crop in my country. However, its long growth period and high water requirement make it highly sensitive to drought, especially during the jointing stage (vegetative growth period) and tasseling stage (transition period between vegetative and reproductive growth), which can reduce yield by 20% to 50%. Therefore, drought has always been one of the limiting factors affecting the stable and increased yield of maize in my country. Drought reduces soil moisture content, and soil moisture is closely related to nitrogen and phosphorus availability, affecting the migration and transformation of nitrogen and phosphorus in the soil, ultimately impacting plant uptake, utilization, and distribution. Secondly, drought leads to water deficit in plants, thus affecting photosynthesis. Crop growth and productivity are the final products of photosynthesis and related physiological processes. Photosynthesis is the main driving force for plant organ formation and dry matter production, and it is also the foundation for plant growth and yield formation. These adverse effects caused by drought stress, by interfering with root development, photosynthesis, and nutrient absorption, ultimately inhibit plant growth and development. Therefore, we hope to find more efficient and environmentally friendly methods to alleviate the adverse effects of drought stress on maize and further solve the problem of maize yield.

[0004] Therefore, providing a method for drought resistance and yield increase in maize based on the synergistic effect of arbuscular mycorrhizal fungi and calcium silicate is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention provides a method for drought resistance and yield increase of maize based on the synergistic effect of arbuscular mycorrhizal fungi and calcium silicate, which alleviates the problems of low growth and development and low yield of maize under drought stress.

[0006] This invention utilizes a special microorganism, arbuscular mycorrhizal fungi, which live in symbiosis with crops, in combination with calcium silicate. When applied in a certain proportion, it increases soil moisture content, improves crop nutrient absorption and water use efficiency, thereby resisting drought stress and increasing corn yield.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: Key points of this invention: ① Method for combined application of arbuscular mycorrhizal fungi and calcium silicate; ② Amount and method of adding arbuscular mycorrhizal fungi and calcium silicate.

[0008] This invention innovatively combines arbuscular mycorrhizal fungi with silicon materials (calcium silicate) to increase maize yield under drought stress.

[0009] A method for drought-resistant and yield-increasing maize based on the synergistic effect of arbuscular mycorrhizal fungi and calcium silicate involves uniformly mixing calcium silicate and arbuscular mycorrhizal fungi inoculum one day before maize sowing and applying the mixture to the soil. The dosage of calcium silicate is 2 kg / mu; the dosage of the arbuscular mycorrhizal fungi inoculum is 5 kg / mu, and the concentration of the arbuscular mycorrhizal fungi inoculum is 10 spores / g. The arbuscular mycorrhizal fungi are *Rhizocarpus heterophyllus* (…). Rhizophagus irregularis The specimen, with accession number CGMCC No. 40760, is deposited at the China General Microbiological Culture Collection Center (CGMCC), located at No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences. The deposit date is August 22, 2023, and the specimen is classified as *Rhizocystis heteromorpha*. Rhizophagus irregularis .

[0010] Silicon (Si) can promote plant growth, enhance plant resistance to multiple stresses, and is increasingly being applied in agriculture, providing new technologies and methods for sustainable agricultural development. Si can promote root growth and increase plant biomass under drought stress. Furthermore, Si can alleviate photosynthetic pigment degradation caused by drought stress, increase gas exchange parameters to enhance photosynthetic capacity under drought stress, promote nutrient absorption, and ultimately promote plant growth.

[0011] Arbuscular mycorrhizal fungi (AMF) also play an important role in plant resistance to drought stress. They can form symbiotic relationships with more than 40% of terrestrial plants and help plants resist drought stress through various pathways, mainly in the following aspects: (1) After AMF successfully infects the host plant, it forms a huge hyphal network and expands the root volume of the plant in terms of morphology and quantity through the hyphal network, thereby increasing the water absorption area and reducing the sap flow resistance between the plant and the soil, thus helping the plant to absorb more water. (2) Promote the absorption of nutrients by plants, such as phosphorus. The hyphae will penetrate into the soil pores that are inaccessible to the smaller root hairs through the cortical cells of the plant roots to absorb nutrients, and the hyphal secretions will recruit phosphate-solubilizing bacteria to mineralize organic phosphorus in the soil that is difficult for plants to use directly, thereby enhancing the plant's absorption and utilization of soil nutrients. (3) Improve plant photosynthetic capacity, enabling them to increase their carbon reserves through efficient photosynthesis, while providing more organic matter to AMFs or other microorganisms, thus enhancing plant growth in drought conditions and improving their adaptability and resistance to drought stress. Arbuscular mycorrhizal fungi can help plants cope with drought stress by regulating multiple mechanisms, which is a way to improve future agricultural production.

[0012] Furthermore, the method is applied to alleviate drought stress in maize.

[0013] Furthermore, the method is applied to increase corn yield.

[0014] This invention eliminates the need for additional chemical fertilizers. By combining microorganisms and calcium silicate in a certain proportion, it can significantly improve crop photosynthetic rate, nutrient absorption, and water use efficiency, providing a new approach for sustainable agricultural development while increasing corn yield.

[0015] As can be seen from the above technical solution, compared with the prior art, the present invention discloses a method for drought resistance and yield increase of maize based on the synergistic effect of arbuscular mycorrhizal fungi and calcium silicate. It establishes a technical method for the combined application of arbuscular mycorrhizal fungi and calcium silicate, which utilizes the mycelial network formed by arbuscular mycorrhizal fungi and roots to increase the absorption area of ​​maize roots. Combined with the effect of calcium silicate, it improves the colonization rate of arbuscular mycorrhizal fungi in maize roots, thereby further improving the efficiency of photosynthesis, nutrient absorption and water use of plants, alleviating the growth and development of maize under drought stress, and ultimately increasing maize yield. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0017] Figure 1 The graph shows the photosynthetic results of maize during the silking-tasseling stage under different treatments; where a represents the bar chart of net photosynthetic rate; b represents the bar chart of stomatal conductance; and c represents the bar chart of transpiration rate.

[0018] Figure 2 Figures showing maize yield and biomass under different treatments; where a represents the box plot of dry weight of maize stems and leaves; b represents the box plot of dry weight of maize roots; and c represents the box plot of maize yield.

[0019] Figure 3 The graph shows the results of nitrogen and phosphorus content in maize plants under different treatments; where a represents a stacked bar chart of total nitrogen content in plants; and b represents a stacked bar chart of total phosphorus content in plants.

[0020] Figure 4 The results are shown in the box plots for soil nutrient content under different treatments; where a represents the box plot of available nitrogen content in soil; and b represents the box plot of available phosphorus content in soil.

[0021] Figure 5 The results of soil moisture content and water use efficiency under different treatments are shown in the figure; where a represents the precipitation and temperature data throughout the growing season; b represents the box plot of soil moisture content at a depth of 0-20cm at harvest; and c represents the box plot of water use efficiency.

[0022] Figure 6 The graph shows the infection rate results after adding arbuscular mycorrhizal fungi; where a represents the infection rate bar charts for the AMF and AMF+Si treatment groups; and b represents the infection micrographs for the AMF and AMF+Si treatment groups. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Example 1

[0025] Arbuscular mycorrhizal fungi are *Heteromorpha rhizocarpium* ( Rhizophagus irregularisThe specimen, with accession number CGMCC No. 40760, is deposited at the China General Microbiological Culture Collection Center (CGMCC), located at No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences. The deposit date is August 22, 2023, and the specimen is classified as *Rhizocystis heteromorpha*. Rhizophagus irregularis Calcium silicate was purchased from Yuanye Biotechnology Co., Ltd.

[0026] 1) Technical solution: (1) Use perlite: peat moss: vermiculite in a volume ratio of 2:1:2 as the culture medium, 5 kg per pot, with Yellow River sorghum as the host plant. Sow 20 sterilized sorghum seeds into the substrate, and add arbuscular mycorrhizal spore suspension (100 spores / pot) for culture. After three months, discard the sorghum plants and collect the substrate. The cultured substrate is used as AMF inoculum (the concentration of arbuscular mycorrhizal fungi inoculum is 10 spores / g) for later use.

[0027] (2) Select uniform-sized, disease-free maize seeds for planting in Heyang County, a semi-arid agricultural area. The maize variety used was Lidan 22, purchased from the local agricultural input market. The planting area was randomly divided into 11.6 m² plots. 2 The plots are divided into 4.0m × 2.9m sections, with 4 rows of corn planted in each section. There is a 0.5m buffer zone between adjacent plots. The cultivation method is ridge cultivation with mulching.

[0028] (3) One day before corn sowing, calcium silicate and arbuscular mycorrhizal fungi inoculum are evenly mixed and spread on the soil. Corn is sown by hole sowing with a plant spacing of 30 cm and a row spacing of 40 cm. The planting density is 4040 plants / mu. One corn seed is planted in each hole when sowing.

[0029] (4) Four treatment groups were set up in the experiment: (1) Control, no additional fertilizer was applied; (2) AMF: arbuscular mycorrhizal fungi inoculum was applied alone (5 kg / mu, 10 spores / g); (3) Si: calcium silicate was applied alone (2 kg / mu); (4) AMF+Si: arbuscular mycorrhizal fungi inoculum (5 kg / mu, 10 spores / g) and calcium silicate (2 kg / mu) were applied together. Each treatment group was set up with 4 replicates. All treatment groups were sown with the same amount of nitrogen, phosphorus and potassium fertilizer as base fertilizer before planting.

[0030] 2) Test the samples: (1) When the corn reaches the silking and tasseling stage, select plants with uniform growth in each plot and use the LI-6400XT portable photosynthesis measurement system (LI-COR, USA) to measure the photosynthetic gas exchange parameters of the auricle.

[0031] The photosynthetic parameters of maize leaves were measured, and the results are as follows: Figure 1 As shown, the combined application of arbuscular mycorrhizal fungi and calcium silicate can significantly increase the net photosynthetic rate, stomatal conductance, and transpiration rate of maize leaves. Under drought stress, stomata regulate the water content of plants by controlling the transpiration rate. High photosynthetic efficiency can increase the plant's carbon reserves, enhance its growth in drought environments, and thus improve its adaptability and resistance to drought stress.

[0032] (2) When the corn grows to maturity, 10 corn plants with uniform growth are continuously sampled from the center of each plot and divided into three parts: roots, stems and leaves and kernels. The samples are blanched in an oven at 105℃ for 30 minutes and then dried at 75℃ until constant weight. The biomass of different parts is measured. Finally, the kernel yield is adjusted to a moisture content of 14%.

[0033] The growth indicators of corn were measured, and the results are as follows: Figure 2 As shown, the combined application of arbuscular mycorrhizal fungi and calcium silicate can significantly increase the dry weight of maize stems, leaves, and roots.

[0034] The yield of corn kernels was measured, and the results are as follows: Figure 2 As shown, the application of arbuscular mycorrhizal fungi and calcium silicate alone can increase the yield of corn kernels. The combined application of the two has the greatest effect on yield, increasing the yield to 780.70 kg / mu, which is 14.00% higher than the control group.

[0035] (3) The dried corn stems, leaves and kernels were crushed, passed through an 80-mesh sieve, and then digested in a microwave digester. The nitrogen and phosphorus content of the plants was determined by a flow analyzer.

[0036] The nutrient content in corn plants was measured, and the results are as follows: Figure 3 As shown, the combined application of arbuscular mycorrhizal fungi and calcium silicate can significantly increase the total nitrogen and total phosphorus content in maize stems, leaves and kernels.

[0037] (4) When the corn reaches maturity, use a soil auger to dig two soil columns (20 cm deep) in each plot, mix them together to form a sample, and determine the soil moisture, available nitrogen and available phosphorus content.

[0038] The soil nutrient content was measured, and the results are as follows: Figure 4 As shown, compared to readily available nitrogen, the combined application of arbuscular mycorrhizal fungi and calcium silicate has a better promoting effect on available phosphorus.

[0039] The soil moisture content was measured, and the results are as follows: Figure 5 As shown, the combined application of arbuscular mycorrhizal fungi and calcium silicate can significantly increase the soil moisture content in the 0-20 cm depth.

[0040] (5) Water use efficiency is calculated by dividing grain yield (adjusted to a moisture content of 14%) by crop evapotranspiration (ETa, mm). Evapotranspiration is calculated using the water balance equation: ETa = ΔW + P + I + G − D − R, where ΔW represents the change in soil moisture storage between planting and harvesting (mm); P represents precipitation (mm); I represents irrigation (mm); R represents surface runoff loss (mm); G represents the contribution of groundwater rising through capillary action (mm); and D represents deep infiltration (mm).

[0041] The crop water use efficiency was measured, and the results are as follows: Figure 5 As shown, the combined application of arbuscular mycorrhizal fungi and calcium silicate can significantly improve the water use efficiency of maize by 0.37 kg / mm·acre. This indicates that under limited water conditions, the combined application of arbuscular mycorrhizal fungi and calcium silicate can better utilize water and convert it into the water necessary for its own growth, thereby increasing the yield.

[0042] (6) Weigh 2 g of fresh corn lateral roots, cut them into pieces of about 1 cm, and place them into tissue embedding boxes. Then, perform alkaline decolorization (10% KOH, 90 ± 1℃ water bath for 30 ~ 90 min), acid activation (20% HCl, room temperature for 8 min), and specific staining (0.05% trypan blue, 90℃ water bath for 15 ~ 30 min). Then, use lactic acid-glycerol decolorization solution (lactic acid: glycerol: water = 1:1:1) for 48 h. After decolorization, select 10 root segments and observe the infection under a microscope. Observe at least 100 fields of view to calculate the infection rate.

[0043] Infection rate was measured in the roots of corn, and the results are as follows: Figure 6 As shown, mycelia and spores were observed in the roots of both the AMF and AMF+Si treatment groups, indicating that AMF successfully established a symbiotic relationship with the plant roots. The infection rate results show that the addition of calcium silicate can increase the infection rate of AMF.

[0044] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for increasing yield of corn by drought resistance based on the synergistic effect of arbuscular mycorrhizal fungi and calcium silicate, characterized in that, One day before corn sowing, calcium silicate and arbuscular mycorrhizal fungi inoculum were evenly mixed and applied to the soil; the dosage of calcium silicate was 2 kg / mu; the dosage of arbuscular mycorrhizal fungi inoculum was 5 kg / mu, and the concentration of the arbuscular mycorrhizal fungi inoculum was 10 spores / g; the arbuscular mycorrhizal fungi was *Rhizocarpus heterophyllus* (…). Rhizophagus irregularis Ri, with accession number CGMCC No.40760.

2. The method of claim 1 for use in alleviating drought stress in maize.

3. The method of claim 1 for use in increasing yield in maize.

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