Seedling raising method capable of promoting strawberry growth

Abstract

The invention relates to a seedling raising method capable of promoting strawberry growth. The method comprises the following steps that plug seedling is adopted, an arbuscular mycorrhizal fungus inoculant and a substrate are evenly mixed, then strawberry seedlings are cut, and the application amount of the inoculant in each plug is that 10-15 g of the arbuscular mycorrhizal fungus inoculant is added into each kilogram of the substrate. The AMF microbial inoculum can form a reciprocal symbiont with strawberry seedlings, promotes strawberry to absorb nutrients, increases the nutrient content, promotes plant growth, and can improve apparent forms such as plant height, stem diameter, root length and chlorophyll content. The AMF microbial inoculum has positive influences on biomass, reproductive growth, fruit quality, seedling raising work application and the like of strawberries, so that the AMF microbial inoculum has a wide application prospect in production and cultivation of strawberries.

Description

Technical Field

[0001] The present invention belongs to the field of seedling cultivation, and particularly relates to a seedling cultivation method for promoting the growth of strawberries. Background Art

[0002] Strawberries are perennial herbaceous plants of the genus Fragaria in the Rosaceae family. Their fruits are brightly colored, crispy and juicy, moderately sour and sweet, rich in fruit aroma, and rich in minerals. They are known as the 'queen of fruits' and are widely popular worldwide. Strawberries have high economic value, a short growth cycle, strong environmental adaptability, relatively easy management, and can promote economic development, making the strawberry industry develop rapidly in recent years.

[0003] However, strawberries have weak resistance to pests and diseases during the seedling cultivation period, low uniformity of daughter plants, low propagation coefficient, small seedlings, small and shallow roots, and are prone to fertilizer damage after fertilization, resulting in large areas of root injury and death or stunted growth. Therefore, finding new methods to strengthen the cultivation of high-quality strawberry seedlings has broad application prospects.

[0004] AMF arbuscular mycorrhizal fungi can improve the resistance of crops to stress such as drought and salinity, enhance the nutritional status of crops, and improve the efficiency of seedling propagation; AMF arbuscular mycorrhizal fungi can form a hyphal network around the roots of plants, thereby expanding the absorption area of plant roots, improving the utilization efficiency of fertilizers, reducing fertilizer usage, and promoting crop growth; AMF arbuscular mycorrhizal fungi directly interact with soil particles through their hyphal network, promoting the formation and stability of soil aggregate structure and increasing crop yields; AMF arbuscular mycorrhizal fungal agents can improve the photosynthetic utilization efficiency of crops, promote the accumulation of dry matter, and are also conducive to the transformation of crops from vegetative growth to reproductive growth, increasing crop yields.

[0005] AMF arbuscular mycorrhizal fungal agents have broad application prospects in agriculture, but there are relatively few research reports on promoting strawberry seedling cultivation, especially the lack of relevant research on the 'Hongyan' strawberry. Summary of the Invention

[0006] Aiming at the deficiencies of the above-mentioned existing technologies, the present invention provides a seedling cultivation method for promoting the growth of strawberries.

[0007] A seedling cultivation method for promoting the growth of strawberries, the method comprising the following steps: using plug trays for seedling cultivation, mixing arbuscular mycorrhizal fungal agents and substrates evenly and then cutting strawberry seedlings, and the application amount of the fungal agents per plug tray is: adding 10 - 15 g of arbuscular mycorrhizal fungal agents per kilogram of substrate.

[0008] Preferably, the arbuscular mycorrhizal fungi is one of Funneliformis mosseae, Acaulospora spp., Glomus claroideum, Rhizophagus irregularis, or Paraglomus occultum.

[0009] Preferably, the arbuscular mycorrhizal fungal inoculant is an Acaulospora inoculant. After inoculation with the Acaulospora inoculant, the root development of seedlings was significantly promoted, such as the number and length of roots; it could increase the biomass of strawberries, such as the fresh weight of plants, the fresh weight of above-ground parts, and the fresh weight of roots; it could promote the reproductive growth of strawberries, such as enabling the plants to flower earlier and have more flowers.

[0010] Preferably, the arbuscular mycorrhizal fungal inoculant is preferably a Rhizophagus irregularis inoculant. After inoculation with the Rhizophagus irregularis inoculant, the root development of seedlings was significantly promoted, such as the number and length of roots; it could increase the biomass of strawberries, such as the fresh weight of plants, the fresh weight of above-ground parts, and the fresh weight of roots; it could promote the reproductive growth of strawberries, such as enabling the plants to flower earlier and have more flowers; it had a relatively high infection rate, such as the infection rate could reach 90% or higher or any range in between after five months of inoculation; it could increase the sugar content and sugar-acid ratio of strawberries, thereby improving the fruit quality.

[0011] Preferably, the preparation method of the substrate is as follows: Take vermiculite, peat, and river sand and mix them. Sieve them through a 2-mm fine mesh, sterilize them with high-pressure steam at 121 °C for 2 h, cool them to room temperature, apply water-soluble fertilizer in a ratio of 1000:1, and mix and stir evenly to form the substrate. The volume ratio of vermiculite:peat:river sand is 1:1:1. The water-soluble fertilizer is Flourish (ICL Group) diluted with water at a ratio of 1:2000 times. 1 g of the dose is diluted with water to 2000 ml and dissolved with warm water 1-2 hours before use. Fertilize intermittently, once every two weeks.

[0012] Preferably, the production method of the AMF fungal inoculant is: Enrich and culture the AMF fungal inoculant using maize seedlings.

[0013] Preferably, the enrichment and culture of the AMF fungal inoculant using maize seedlings is specifically as follows: Disinfect maize seeds with 10% hydrogen peroxide for 10 min, rinse them with sterile water 3-5 times, soak them for 3 h and then sow them. After about 3 leaves grow, inoculate with AMF fungi, enrich and culture them in a sterilized substrate for 4 months, then cut off the above-ground parts, and retain the roots, spores, hyphae, and mycorrhizal root segments to obtain the AMF fungal inoculant. The spore content in the AMF fungal inoculant is ≥10 spores / g, and the nutrient fertilizer in the culture substrate and the decomposition products during the reproduction of AMF fungi act as fungal protectants to promote plant growth.

[0014] Preferably, the strawberry seedlings are annual stolon seedlings. The method includes cold-treating the stolon seedlings before transplantation, such as refrigerating them at 4 °C for 7 days.

[0015] Preferably, the strawberry is the 'Benihoppe' strawberry.

[0016] Beneficial effects:

[0017] Arbuscular mycorrhizal fungi (AMF) are beneficial microorganisms. The successful infection of plant roots by AMF is a prerequisite for their ability to promote plant growth. In this invention, an AMF inoculant was applied to the roots of strawberry seedlings. The AMF inoculant had a high infection rate on strawberries, reaching up to 57.82% after two months of infection and up to 100% after five months of infection. It can be seen that the AMF inoculant of this invention can form a mutualistic symbiont with strawberry seedlings, promoting the absorption of nutrients by strawberries, increasing nutrient content, promoting plant growth, and improving the apparent morphology, such as plant height, stem diameter, root length, and chlorophyll content. This invention has a positive impact on aspects such as the biomass, reproductive growth, fruit quality, and seedling cultivation of strawberries. Therefore, the AMF inoculant of this invention has broad application prospects in the production and cultivation of strawberries. Description of the Drawings

[0018] Figure 1 Shows the effects of inoculating different AMF fungi on the seedlings of 'Hongyan' strawberries. Among them, CK: plants in the control group, Ri: plants in the Ri inoculant treatment group, GZ1: plants in the GZ1 inoculant treatment group, HTJ: plants in the HTJ-2-60 inoculant treatment group, E16-1-32: plants in the E16-1-32 inoculant treatment group, YN: plants in the YN-2-8 inoculant treatment group. The scale bar in the figure is 4 cm.

[0019] Figure 2 Shows the root infection status of 'Hongyan' strawberries after inoculating AMF fungi. Among them, Figure A: control blank, strawberry roots without inoculating arbuscular mycorrhizal fungi (AMF), serving as the control group. Figure B: intracellular hyphae, responsible for transporting nutrients inside plant roots. Figure C: arbuscule structure. Figure D: intracellular spores. Figure E: extracellular spores. Figure F: vesicle structure.

[0020] Figure 3 Shows the statistical results of the root infection rate of 'Hongyan' strawberries after inoculating different types of AMF fungi. Among them, "2 months" represents the root infection rate measured two months after inoculating AMF fungi, and "5 months" represents the root infection rate five months after inoculation.

[0021] Figure 4 Shows the statistical results of the root infection intensity of 'Hongyan' strawberries after inoculating different AMF fungi. Among them, "2 months" represents the root infection intensity measured two months after infection, and "5 months" represents the root infection intensity measured five months after infection.

[0022] Figure 5Shows the effects of inoculating different AMF fungi on the roots of 'Hongyan' strawberries. Figure A: Whole-plant fresh weight. Figure A shows the changes in the whole-plant fresh weight of 'Hongyan' strawberry plants after inoculating different AMF fungi. Figure B: Shoot fresh weight. Figure B reflects the changes in the shoot fresh weight of strawberry plants after inoculating different AMF fungi. Figure C: Root fresh weight. Figure C shows the changes in the root fresh weight of strawberry roots after inoculating different AMF fungi. Figure D: Root length. Figure D presents the changes in the root length of strawberry roots after being infected by different AMF fungi. Figure E: Root number. Figure E shows the changes in the root number of strawberry roots after inoculating different AMF fungi.

[0023] Figure 6 Shows the effects of inoculating different AMF fungi on the reproductive growth of 'Hongyan' strawberries. Figure A: Plant height. Figure A shows the changes in the plant height of 'Hongyan' strawberry plants after inoculating different AMF fungi. Figure B: Stem diameter. Figure B reflects the changes in the stem diameter of 'Hongyan' strawberry plants after inoculating different AMF fungi. Figure C: Chlorophyll content. Figure C shows the changes in the chlorophyll content of 'Hongyan' strawberry plants after inoculating different AMF fungi.

[0024] Figure 7 Shows the effects of inoculating different AMF fungi on the fruit quality of 'Hongyan' strawberries. Figure A: Brix. Figure B: Sugar-acid ratio.

[0025] Figure 8 Shows the effects of inoculating different AMF fungi on the flowering of 'Hongyan' strawberries. Figure A shows the phenotypic differences of strawberry plants after being infected by different AMF fungi. Figure B counts the number of flowers of 'Hongyan' strawberries under different AMF treatments. Detailed implementation method

[0026] Example

[0027] A seedling-raising method that can promote the growth of strawberries. This method includes the following steps: using plug trays for seedling raising, mixing the arbuscular mycorrhizal fungal inoculant and the substrate evenly and then cutting strawberry seedlings. The application amount of the inoculant per plug tray is 10 - 15 g of arbuscular mycorrhizal fungal inoculant added per kilogram of substrate.

[0028] As an embodiment of the present invention, the arbuscular mycorrhizal fungus is one of Funneliformis mosseae, Acaulospora spp., Glomus claroideum, Rhizophagus irregularis, or Paraglomus occultum.

[0029] As an embodiment of the present invention, the arbuscular mycorrhizal fungal inoculant is an Acaulospora spp. inoculant. After inoculating with the GZ1 inoculant, it significantly promotes the root development of seedlings, such as the number and length of roots; has a high infection rate, for example, the infection rate can reach 32%, 35% or higher or any range in between two months after inoculation; can increase the biomass of strawberries, such as plant fresh weight, shoot fresh weight, and root fresh weight; can promote the reproductive growth of strawberries, such as plant height, stem diameter, and chlorophyll content.

[0030] As an embodiment of the present invention, the arbuscular mycorrhizal fungal inoculant is preferably Rhizophagus irregularis inoculant. After inoculating with the Ri inoculant, the root development of seedlings is significantly promoted, such as the number and length of roots; it can increase the biomass of strawberries, such as the fresh weight of plants, the fresh weight of above-ground parts, and the fresh weight of roots; it can promote the reproductive growth of strawberries, such as plant height, stem diameter, and chlorophyll content; it can increase the sugar content and sugar-acid ratio of strawberries, thereby improving the fruit quality.

[0031] As an embodiment of the present invention, the preparation method of the substrate is as follows: Take vermiculite, peat, and river sand and mix them. Sieve them through a 2-mm fine mesh, sterilize them with high-pressure steam at 121 °C for 2 h, cool them to room temperature, and apply water-soluble fertilizer in a ratio of 1000:1. Mix and stir evenly to form the substrate. The volume ratio of vermiculite:peat:river sand is 1:1:1.

[0032] As an embodiment of the present invention, the production method of the AMF fungal inoculant is as follows: Use corn seedlings to enrich and culture the AMF fungal inoculant. Specifically: Disinfect corn seeds with 10% hydrogen peroxide for 10 min, rinse them with sterile water 3-5 times, soak them for 3 h and then sow them. After about 3 leaves grow, inoculate with AMF fungi, and after enriching and culturing in a sterilized substrate for 4 months, cut off the above-ground parts, and retain the roots, spores, hyphae, and mycorrhizal root segments to obtain the AMF fungal inoculant. The spore content in the AMF fungal inoculant is ≥10 spores / g, and the nutrient fertilizers in the culture substrate and the decomposition products during the reproduction of AMF fungi act as fungal protectants to promote plant growth.

[0033] As an embodiment of the present invention, the strawberry seedlings are annual stolon seedlings. The method includes cold-treating the stolon seedlings before transplantation, such as refrigerating them at 4 °C for 7 days.

[0034] As an embodiment of the present invention, the strawberry is 'Benihoppe' strawberry.

[0035] Test Example

[0036] Funneliformis mosseae, Acaulospora spp., Claroideoglomus lamellosum, Rhizophagus irregularis, and Paraglomus sp. were provided by the Institute of Microbiology, Guangxi Academy of Agricultural Sciences. (Funneliformis mosseae: strain name Funneliformis mosseae, strain preservation number BGSC-74; Claroideoglomus lamellosum: strain name Claroideoglomus lamellosum, preservation number BGSC-60; Acaulospora kentinensis: strain name Acaulospora kentinensis, strain preservation number BGSC-141; Rhizophagus irregularis: strain name Rhizophagus irregularis, strain preservation number BGSC-110; Paraglomus sp.: strain name Paraglomus brasilianum, strain preservation number BGSC-94).

[0037] Funneliformis mosseae was designated as No. E16-1-32.

[0038] Acaulospora kentinensis was designated as No. GZ1.

[0039] Claroideoglomus lamellosum was designated as No. HTJ-2-60.

[0040] Rhizophagus irregularis was designated as No. Ri.

[0041] Paraglomus sp. was designated as No. YN-2-8.

[0042] The experiment was conducted in the glass greenhouse of the Institute of Modern Agriculture, Peking University from July 2023 to October 2024. Annual 'Benihoppe' strawberry stolon seedlings with consistent growth and good vigor were selected and 32-hole seedling trays were used. They were treated with AMF inoculum. A total of 5 inoculation treatments (GZ1, Ri, E16-1-32, YN-2-8, and HTJ-2-60) and 1 non-inoculation treatment as a control (CK) were designed; the AMF fungal inoculum was mixed evenly with the substrate and then strawberry seedlings were cuttaged, and the roots of strawberry seedlings were inoculated with the AMF fungal inoculum.

[0043] The inoculation treatment adopted the uniform mixing application method. The AMF inoculum was mixed evenly with the substrate and then strawberry seedlings were transplanted. Each seedling tray contained approximately 5 kg of substrate and 15 g of AMF inoculum was applied. The plants were watered twice a week and water-soluble fertilizer was applied once every two weeks.

[0044] Two months after transplantation, the main morphological indexes of the seedlings during the seedling stage, such as root length, root number, fresh weight of the plant, and fresh weight of the root, were measured; the mycorrhizal infection status was observed, and the root infection rate was measured; the whole plant was taken to measure the dry and fresh weights of the plant;

[0045] Five months after planting, the main growth indexes of the plant, such as plant height, stem diameter, and chlorophyll content, were measured; the plant roots were taken to measure the root number, fresh and dry weights of the roots; the mycorrhizal infection status was observed, and the root infection rate of the treatment group was measured; the chlorophyll content of the plant leaves was measured; the whole plant was taken to measure the dry and fresh weights of the plant; the leaves and roots of the plant were quickly frozen in liquid nitrogen and stored at -80 °C for later use, and then a series of physiological indexes were measured;

[0046] When the plants began to bear fruit, the fruit quality of the treatment group and the control group, such as sugar content and sugar-acid ratio, was measured, and the time of the first fruit setting was recorded.

[0047] For the measurement of the infection rate, the trypan blue staining method was used, which mainly consisted of the following steps: Root cutting: The roots were cut into small segments about 1 cm long and placed in a 50 mL centrifuge tube. Clearing: Pour 10% KOH solution to submerge all the root segments, heat in a 90 °C water bath for 45 min, then pour out the KOH solution, and rinse three times with distilled water and drain the water. Acidification: Immerse with 1% HCl for 3 min and then pour out the acid solution. Staining: Immerse the acidified roots with 0.05% trypan blue staining solution for staining, take them out after 5 min in a 90 °C water bath for observation, pour out the trypan blue staining solution, rinse several times with distilled water, and drain the water. Decolorization: Immerse the stained roots with acidified glycerol and store them in a centrifuge tube. Using the grid crossing method, the roots were laid flat on a transparent culture dish with grid lines drawn, and the number of intersections of the stained root segments with the grid lines was counted. The infection rate was the proportion of the infection intersections to the total intersections.

[0048] For the measurement of the main morphological indexes, a ruler was used to measure the plant height and petiole length of the plant, and a vernier caliper was used to measure the stem diameter of the plant. The plant height was from the substrate to the highest point of the plant; the stem diameter was the stem thickness at 1 / 2 of the newly developed branch; the root length was the length from the junction of the root and stem to the tip of the longest root of the plant; the length of the new branch was the longest branch of the whole plant produced in the current year.

[0049] For the measurement of the dry / fresh weight of the plant, after the whole plant was washed clean with tap water and dried, the fresh weights of the above-ground part and the underground part were taken separately, and after blanching at 105 °C in an oven for 15 min, it was dried at 75 °C to a constant weight and the dry weight was weighed.

[0050] For the measurement of the chlorophyll content, a spad502 chlorophyll meter (Konica Minolta, Japan) was used to measure the chlorophyll content. Three leaves of each plant were measured and averaged, which was recorded as the final chlorophyll content of the sample of this plant.

[0051] For the measurement of the sugar content of the fruit, an Atago (ATAGO, PAL-1, Japan) hand-held digital refractometer was used to measure the sugar content of the fruit.

[0052] For the determination of the fruit sugar-acid ratio, an Atago (ATAGO, PAL-BXACID F5, Japan) handheld digital refractometer was used to measure the fruit sugar content and acidity. First, the sugar content was directly sampled and measured, and then the sample was diluted proportionally and the acidity was measured. The instrument automatically displayed the sugar-acid ratio.

[0053] The inoculation of AMF inoculum in this application can effectively promote the root development of 'Benihoppe' strawberries during the seedling stage. As Figure 1 shown, the root number, length, and fresh weight after inoculation with Ri inoculum and GZ1 inoculum were better than those of the control group.

[0054] After inoculation with AMF fungi, as Figure 2 shown, obvious structures such as hyphae, arbuscules, and vesicles could be seen on the roots of 'Benihoppe' strawberries. Among them, Figure A: Control blank. The strawberry roots without inoculation with arbuscular mycorrhizal fungi (AMF) were used as the control group for comparative observation of the structural changes after AMF infection. It can be seen from the figure that there is no AMF colonization in the blank group. Figure B: Intraradical Hyphae. Responsible for transporting nutrients inside the plant roots. The figure shows the expansion of AMF hyphae inside the strawberry roots. The hyphae are distributed in a net-like pattern and form a tight connection with the root cells, indicating that AMF has successfully infected the strawberry roots. Figure C: Arbuscule structure. The figure shows the arbuscule structure (Arbuscules) formed by AMF inside the strawberry root cells. Arbuscules are the main sites for nutrient exchange between AMF and plants, and their branched structure significantly increases the contact area between plants and fungi. Figure D: Intraradical spores. The figure shows the spore structure formed by AMF inside the strawberry roots. Spores are the propagules of AMF, with a thick-walled structure, which can survive in the soil for a long time and be used as inoculum for transmission and preservation. Figure E: Extraradical spores. The picture shows the spores formed by AMF on the extraradical hyphae of strawberries. Spores are the asexual reproductive organs of AMF and also nutrient storage structures. Figure F: Vesicle structure. The figure shows the vesicle structure formed by AMF inside the strawberry roots. Vesicles are formed by the swelling of the ends of intraradical hyphae, rich in lipids and carbohydrates, and are considered to be the nutrient storage structures of AMF.

[0055] The infection rate of AMF reflects the proportion of the plant's root system infected by arbuscular mycorrhizal fungi. The infection intensity of AMF refers to the degree of development of AMF within the plant root system in the symbiont formed by arbuscular mycorrhizal fungi and the plant root system. It is an important indicator for evaluating the symbiotic state between AMF and host plants and their physiological and ecological functions. The infection intensity is usually evaluated by observing and measuring the development of AMF in the root system, including the distribution of hyphae in the root system, the formation of arbuscules and vesicles, etc. The determination of the infection intensity can help understand the colonization of AMF in the plant root system and its effects on plant nutrient uptake and stress resistance, etc.

[0056] The infection degrees of AMF on the roots of 'Hongyan' strawberries are different. After two months of treatment, the infection rates of the three AMF inoculants GZ1, E16-1-32, and HTJ can all reach about 35%, and the infection rates of the inoculants Ri and YN-2-8 are about 18%. After five months of treatment, the infection rates of E16-1-32, HTJ-2-60, Ri, and YN-2-8 basically all reach 100%, and the infection rate of GZ1 is about 67%. The infection intensity of strawberry plants after two months of treatment is relatively low, probably because AMF has just infected the plant root system and the fungus is in the growth stage. At five months, the infection intensity has increased. Among them, the infection intensity of HTJ is about 57%, and the infection intensity of Ri can reach 43%, indicating that these two strains can infect plants quickly and the growth rate of the strains is relatively fast. Specifically, as shown in Table 1, Table 2 and Figure 3 、 4 shown.

[0057] Table 1 Statistical results of infection indicators of 'Hongyan' strawberries after inoculation with different AMF fungi

[0058]

[0059] Table 2 Statistical results of infection indicators of 'Hongyan' strawberries after inoculation with different AMF fungi

[0060]

[0061] Figure 3 shows the statistical results of the root infection rates of 'Hongyan' strawberries after inoculation with different species of AMF fungi. Among them, '2 months' represents the root infection rate measured two months after inoculation with AMF fungi, and '5 months' represents the root infection rate after five months of inoculation. The root infection rate is the ratio of the infection structures such as hyphae, arbuscules, and vesicles to the total number of intersections of the root system, and is obtained by microscopic observation and statistics. Different species of AMF fungi have different infection abilities on strawberry roots, which reflects the growth characteristics of AMF and its symbiotic relationship with host plants.

[0062] Figure 4The statistical results of the root infection intensity of 'Hongyan' strawberries inoculated with different AMF fungi are shown. Among them, "2 months" represents the root infection intensity measured two months after infection, while "5 months" represents the root infection intensity measured five months after infection. The root infection intensity reflects the development degree and nutrient exchange ability of AMF in the roots, and is closely related to the growth and nutrient absorption of plants. The differences in the infection intensity of different AMF fungi indicate that their colonization ability in the roots and the promotion effect on plant growth may be different. The significant differences in the infection rate and infection intensity of different species of AMF fungi on strawberry roots are caused by the different growth characteristics of AMF and the symbiotic relationship with the host plant.

[0063] Inoculation with five different AMF fungi can all affect the root development of 'Hongyan' strawberries to varying degrees. Two months after inoculation, compared with the control group, the root length, root number, and root fresh weight in the Ri and GZ1 treatment groups increased significantly. At the same time, the plant fresh weight and the aboveground fresh weight were significantly higher than those of the control group plants. The specific results are shown in Table 3 and Figure 5 as follows.

[0064] Table 3 Effects of inoculating different AMF fungi on the roots of 'Hongyan' strawberries

[0065]

[0066]

[0067] Figure 5Show the effects of inoculating different AMF fungi on the roots of 'Hongyan' strawberries. Figure A: Whole-plant fresh weight. Figure A shows the changes in the whole-plant fresh weight of 'Hongyan' strawberry plants after inoculating different AMF fungi. After inoculating AMF fungi, the whole-plant fresh weight of strawberry plants increased significantly, indicating that AMF fungi promoted the overall growth and development of plants by improving root function. Figure B: Shoot fresh weight. Figure B reflects the changes in the shoot fresh weight of strawberry plants after inoculating different AMF fungi. After inoculating AMF fungi, the shoot fresh weight of strawberry plants increased significantly. This may be because mycorrhizal symbiosis improved the root's ability to absorb nutrients and water, thus promoting shoot growth. Figure C: Root fresh weight. Figure C shows the changes in the root fresh weight of strawberry plants after inoculating different AMF fungi. The inoculation of AMF fungi significantly increased the root fresh weight, indicating that AMF increased the root biomass by enhancing root growth and development. Figure D: Root length. Figure D presents the changes in root length after different AMF fungi infected strawberries. After inoculating AMF fungi, the root length increased significantly. This may be because AMF promoted root growth and expansion, enhancing the root's ability to utilize soil resources. Figure E: Root number. Figure E shows the changes in the root number of strawberry plants after inoculating different AMF fungi. The inoculation of AMF fungi significantly increased the root number, indicating that AMF increased the root absorption ability by promoting root branching development, thus increasing the root number.

[0068] Inoculating five different AMF fungi can all affect the reproductive growth of 'Hongyan' strawberries to varying degrees. Figure 6Show the effects of inoculating different AMF fungi on the reproductive growth of 'Hongyan' strawberries. Figure A: Plant height. Figure A shows the changes in the plant height of 'Hongyan' strawberries after inoculating different AMF fungi. Plant height is an important indicator to measure the growth potential of plants and reflects the vegetative growth status of plants. After inoculating AMF fungi, the plant height of strawberries increased, indicating that AMF promoted the vegetative growth of plants to a certain extent. Figure B: Stem diameter. Figure B reflects the changes in the stem diameter of 'Hongyan' strawberries after inoculating different AMF fungi. Stem diameter is an important manifestation of the nutrient transport capacity of plants. The thicker the plant stem, the higher the nutrient transport efficiency and the stronger the ability to resist adversity stress. After inoculating AMF fungi, the stem diameter of strawberry plants increased to a certain extent, which may be due to the mycorrhizal symbiotic relationship enhancing the absorption of mineral elements (such as phosphorus and nitrogen) by the roots, thus making the plants stronger. Figure C: Chlorophyll content. Figure C shows the changes in the chlorophyll content of 'Hongyan' strawberries after inoculating different AMF fungi. Chlorophyll is a key pigment in photosynthesis, and its content directly affects photosynthetic efficiency and plant growth and development. After inoculating AMF fungi, the chlorophyll content increased, indicating that AMF promoted photosynthesis by improving root function and providing more nutrients for leaves. The results showed that compared with the control group, after inoculating AMF fungi, the plant height, stem diameter, and chlorophyll content of strawberries all increased, indicating that AMF fungi could significantly promote the growth of strawberries. Among them, the plant height and stem diameter of the RI strain treatment group were significantly higher than those of other treatment groups, indicating that this strain had a stronger effect in promoting plant growth. In addition, after inoculating the YN-2-8 inoculant, the chlorophyll content of strawberries was significantly higher than that of the control group, which may be related to the promoting effect of the YN-2-8 inoculant on photosynthesis. The specific data are shown in Table 4, which details the growth index data of each treatment group, further verifying the positive effect of AMF fungi on the reproductive growth of strawberries.

[0069] Table 4 Effects of inoculating different AMF fungi on the reproductive growth of 'Hongyan' strawberries

[0070]

[0071] Inoculating different AMF inoculants can have different effects on the fruit quality of 'Hongyan' strawberries. Inoculating the Ri and GZ1 inoculants increased the sugar content and fruit sugar-acid ratio of 'Hongyan' strawberries, as shown in Table 5 and Figure 7 as follows.

[0072] Table 5 Effects of inoculating different AMF fungi on the fruit quality of 'Hongyan' strawberries

[0073]

[0074]

[0075] Figure 7Shows the effects of inoculating different AMF fungi on the fruit quality of 'Hongyan' strawberries. AMF forms a symbiotic relationship with strawberry roots, which can help strawberries absorb more mineral elements (such as N, P, K, etc.), thus promoting the vegetative growth of strawberries and the improvement of fruit quality, and further improving the fruit flavor. Figure A: Brix. Brix is an important indicator to measure the sweetness of fruits, reflecting the content of soluble sugars in fruits. After inoculating with AMF fungi, the brix of strawberry fruits has increased, probably because AMF fungi promote the absorption of mineral elements in the soil by strawberries, thereby improving the efficiency of photosynthesis and increasing sugar accumulation. Figure B: Sugar-acid ratio. The sugar-acid ratio is an important indicator of fruit flavor, reflecting the balance between fruit sweetness and acidity. A higher sugar-acid ratio means the fruit is sweeter and has a better flavor. After inoculating with AMF fungi, the sugar-acid ratio of strawberry fruits has increased, probably because AMF fungi not only increase the content of soluble sugars in fruits but also reduce the content of titratable acids, thus increasing the sugar-acid ratio.

[0076] After inoculating with the AMF inoculant, there are obvious differences in the flowering status between the treatment group and the control group. Figure 8 Shows the effects of inoculating different AMF fungi on the flowering of 'Hongyan' strawberries. Figure A shows the phenotypic differences of strawberry plants after being infected with different AMF fungi. By observing the overall flowering status of strawberry plants after AM infection, it can be intuitively observed that after AMF treatment, the plants flower earlier. Figure B counts the number of flowers of 'Hongyan' strawberries under different AMF treatments. By comparing the number of flowers in each treatment group, the regulatory effects of different AMF strains on strawberry flowering can be clarified. For example, some AMF may significantly increase the number of flowers. This difference may be related to AMF improving soil nutrient absorption and promoting strawberries to enter the reproductive growth stage earlier. The increase in the number of flowers not only reflects the positive effect of AMF on strawberry growth but may also be closely related to the improvement of fruit yield and quality. Figure 8 The results show that after applying AMF, the strawberry flowers have fully opened, while the flowers in the control group have not yet opened. This indicates that inoculating AMF can significantly promote the flowering process of strawberries, making the flowers enter the mature stage earlier. Table 6 counts the number of flowers of strawberries at different time points, and the results show that the number of flowers in the treatment group inoculated with AMF is significantly more than that in the control group. This shows that inoculating AMF can not only advance the flowering time of strawberries but also increase the number of flowers, thus improving the reproductive potential of strawberries.

[0077] Table 6 Effects of inoculating different AMF fungi on the number of flowers of 'Hongyan' strawberries

[0078]

[0079] The present invention can be embodied in other specific forms without departing from the spirit or main characteristics of the invention. Therefore, from any point of view, the above-described embodiments of the present invention should only be considered as illustrative of the present invention and not as limiting it. The claims define the scope of the present invention, while the above description does not indicate the scope of the present invention. Therefore, any change within the meaning and scope equivalent to the claims of the present invention should be considered as included within the scope of the claims of the present invention.

Claims

1. A seedling raising method for promoting the growth of strawberries, characterized in that, The seedling raising method includes the following steps: Use plug trays for seedling raising. Mix the arbuscular mycorrhizal fungal inoculant and the substrate evenly, and then cuttage strawberry seedlings. The application rate per plug tray is 10-15 g of arbuscular mycorrhizal fungal inoculant added per kilogram of the substrate.

2. The seedling raising method according to claim 1, wherein The arbuscular mycorrhizal fungi are one of Funneliformis mosseae, Acaulospora spp., Glomus claroideum, Rhizophagus irregularis, and Paraglomus spp.

3. The seedling raising method for promoting the growth of strawberries according to claim 2, characterized in that, The arbuscular mycorrhizal fungal inoculant is Acaulospora inoculant.

4. The seedling raising method for promoting strawberry growth according to claim 2, characterized in that, The arbuscular mycorrhizal fungal inoculant is preferably Rhizophagus irregularis inoculant.

5. The seedling raising method for promoting the growth of strawberries according to claim 1, characterized in that, The preparation method of the substrate is as follows: Take vermiculite, peat, and river sand and mix them. Sieve them through a 2-mm fine mesh, sterilize them with high-pressure steam at 121 °C for 2 h, cool them to room temperature, apply water-soluble fertilizer in a ratio of 1000:1, and mix and stir evenly to form the substrate; the volume ratio of vermiculite:peat:river sand is 1:1:

1.

6. The seedling raising method for promoting the growth of strawberries according to claim 1, characterized in that, The production method of the arbuscular mycorrhizal fungal inoculant is as follows: Use corn seedlings to enrich and culture the arbuscular mycorrhizal fungal inoculant.

7. The seedling raising method for promoting the growth of strawberries according to claim 6, characterized in that, The use of corn seedlings to enrich and culture the arbuscular mycorrhizal fungal inoculant is specifically as follows: Disinfect corn seeds with 10% hydrogen peroxide for 10 min, rinse them with sterile water 3-5 times, soak them for 3 h and then sow them. After about 3 leaves grow, inoculate with arbuscular mycorrhizal fungi, enrich and culture them in the sterilized substrate for 4 months, then cut off the above-ground part, and retain the roots, spores, hyphae, and mycorrhizal root segments to obtain the arbuscular mycorrhizal fungal inoculant.

8. The seedling raising method for promoting strawberry growth according to claim 1, wherein, The strawberry seedlings are annual stolon seedlings.

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