A method for increasing the vitamin c content of strawberry fruit

Abstract

The application provides a method for improving the vitamin C content of strawberry fruits, which covers screening and blue light pretreatment during seedling stage, preparation of cultivation substrate, transplanting of seedlings, rhizosphere nutrition regulation during growth stage, exogenous regulation during fruit enlargement stage, red light supplement during maturation stage, and whole-process environmental control. By directionally inducing the activity of key enzymes for vitamin C synthesis, accurately matching the nutritional requirements, supplementing the precursor substances, strengthening the antioxidant protection of fruits, and optimizing the light environment, a whole-cycle nutrition improvement system is constructed, and technical bottlenecks such as limited single regulation effect and nutritional imbalance are broken. The method can significantly improve the vitamin C content of strawberry fruits, simultaneously improve the comprehensive quality such as flavor and storage property, is suitable for multiple scenes such as facility cultivation, pot culture, and soilless culture, is green, safe, and free of chemical residues, and can be widely applied to the field of high-quality strawberry planting.

Description

Technical Field

[0001] This invention relates to the field of strawberry cultivation, and more specifically, to a method for increasing the vitamin C content of strawberry fruits. Background Technology

[0002] Strawberries are a popular fresh berry enjoyed by consumers worldwide. With their sweet and tart flavor and rich nutritional content, they hold a significant share of the berry market. Vitamin C, a core nutritional indicator of strawberries, is a key factor in assessing fruit quality, directly impacting the fruit's antioxidant capacity, health benefits, and consumer acceptance. As living standards improve, the market demand for strawberries with high vitamin C content continues to grow, creating an urgent need for precision cultivation techniques.

[0003] Current strawberry cultivation has seen numerous explorations focused on increasing vitamin C content, but existing technologies still have significant limitations: they focus on optimizing single aspects, such as simply increasing nitrogen fertilizer, spraying vitamin C solution, or selecting high-yield varieties. However, the synthesis and accumulation of vitamin C in strawberries is a complex physiological process that spans the entire cycle from seedling to fruiting, influenced by multiple factors including light, nutrition, and hormones. Single fertilization can only supplement some nutrients and cannot activate the plant's endogenous synthase activity; direct spraying of vitamin C is difficult for the fruit to effectively absorb and convert, and it is easily degraded in the environment, failing to achieve stable long-term accumulation. Ultimately, the improvement often falls short of market expectations.

[0004] Current cultivation methods largely rely on compound fertilizers or general-purpose nutrient solutions, which are insufficient to meet the precise nutritional needs of strawberries at different growth stages. For example, excessive nitrogen fertilizer during the growing season can lead to excessive vegetative growth, with leaves consuming large amounts of nutrients and inhibiting vitamin C accumulation in the fruit; insufficient phosphorus fertilizer will hinder the transport of nutrients to the fruit, resulting in inadequate nutrient supply. In addition, conventional fertilization lacks targeted supplementation of vitamin C synthesis precursors and coenzymes, failing to open up key pathways for nutrient conversion, leading to low efficiency in nutrient accumulation in the fruit.

[0005] Current cultivation methods largely rely on natural light. On cloudy or rainy days, or in greenhouse cultivation, the intensity and duration of light are insufficient, and the regulatory effects of light quality on plant physiology are not specifically utilized. Blue light can induce the activity of vitamin C synthase, and red light can promote the transport of nutrients in fruits. However, conventional cultivation lacks precise supplementation of specific light qualities, resulting in the plant's endogenous physiological mechanisms not being fully activated, and the natural potential for vitamin C synthesis and accumulation not being realized. During the fruit enlargement and ripening stage of strawberries, vitamin C is easily degraded by oxidation and enzymatic degradation, but current technologies generally do not provide protective measures for this critical period. High temperatures, strong light, or pests and diseases in the later stages of fruit growth accelerate vitamin C loss. Furthermore, the use of conventional pesticides may damage the fruit's endogenous antioxidant system, further reducing vitamin C content and ultimately affecting fruit quality and nutritional value.

[0006] In summary, existing technologies cannot achieve multi-factor synergistic regulation throughout the entire growth cycle, making it difficult to stably and efficiently increase the vitamin C content of strawberry fruits. At the same time, they are prone to causing problems such as nutritional imbalance and uneven fruit quality. Therefore, a method to increase the vitamin C content of strawberry fruits is proposed. Summary of the Invention

[0007] The purpose of this invention is to address the problems raised in the existing background technology. To achieve the above-mentioned objective, this invention provides the following technical solution: a method for increasing the vitamin C content of strawberry fruit, comprising the following steps: Step 1, seedling selection during the seedling stage: selecting strawberry seedlings at the three-leaf-one-heart stage, free from pests and diseases, with dark green leaves and well-developed root systems; Step 2, Blue light pretreatment during seedling stage: The selected seedlings are subjected to light treatment, providing 14-16 hours of composite light with an intensity of 25,000-30,000 lux per day. From 8:00 am to 12:00 pm, supplement with blue light accounting for 15%-20% of the total light intensity with a wavelength of 450-470 nm. The treatment is carried out continuously for 7-10 days. Step 3, Preparation of cultivation substrate: Mix peat moss, vermiculite, and well-rotted sheep manure in a volume ratio of 5:3:2, adjust the pH value of the substrate to 5.5-6.5, sterilize at high temperature, and then put it into the cultivation container; Step 4, Seedling Transplanting: Transplant the pretreated strawberry seedlings into the prepared cultivation substrate. The planting depth of each seedling should be such that the roots are completely buried in the substrate and the heart leaves are exposed above the surface. Water thoroughly after transplanting. Step 5, Root zone nutrition regulation during the growth period: Starting 10 days after transplanting, apply a special nutrient solution every 15 days, 200-300ml per plant each time, until the fruit enlargement period. Step 6, exogenous regulation during fruit enlargement: When the diameter of strawberry fruit reaches 0.8-1.2cm, spray an exogenous regulator every 7 days for 2-3 consecutive times; the exogenous regulator formula is: L-ascorbic acid precursor 200-250mg / L, tea polyphenols 50-80mg / L, calcium chloride 100-150mg / L, and water as the solvent; Step 7, Red light supplementation during ripening: After the strawberry fruit enters the color-changing stage, adjust the light duration to 12-14 hours per day and the intensity to 20,000-25,000 lux. At the same time, supplement with red light with a wavelength of 620-660nm for 2-3 hours every afternoon from 5:00 to 8:00 until the fruit ripens. Step 8, Environmental Management during the Growing Period: Maintain a daytime temperature of 20-25℃ and a nighttime temperature of 8-12℃, with an air humidity of 60%-70% throughout the growing period. Remove old leaves, diseased leaves, and lateral buds every 10 days to ensure good ventilation and light penetration for the plants.

[0008] As a preferred technical solution of the present invention, the composite lighting in step 2 is a combination of natural light and LED fill light, with the LED fill light providing the full light intensity on cloudy or rainy days.

[0009] As a preferred technical solution of the present invention, the high-temperature sterilization in step 3 involves sterilizing the mixed matrix at 121°C for 20-30 minutes and then cooling it for later use.

[0010] As a preferred technical solution of the present invention, the special nutrient solution in step 5 is prepared and used immediately. The formula of the special nutrient solution is as follows: calcium nitrate 300-350 mg / L, potassium nitrate 200-250 mg / L, ammonium dihydrogen phosphate 80-100 mg / L, magnesium sulfate 100-120 mg / L, boric acid 0.5-0.8 mg / L, manganese sulfate 0.3-0.5 mg / L, zinc fertilizer 0.2-0.3 mg / L, L-cysteine ​​0.5-1.0 mg / L, and vitamin B6 0.3-0.5 mg / L. When preparing the solution, the macro-elements are dissolved first, and then the micro-elements, L-cysteine ​​and vitamin B6 are added in sequence. After stirring evenly, the pH is adjusted to 5.5-6.0.

[0011] As a preferred technical solution of the present invention, the exogenous regulator in step 6 is sprayed before 9:00 am or after 4:00 pm, and the spraying is done until the back of the leaves and the surface of the fruit are evenly moistened, avoiding spraying during the midday strong light period.

[0012] As a preferred technical solution of the present invention, the L-ascorbic acid precursor in step 6 is one or a mixture of two of L-galactose and L-gulonic acid-1,4-lactone in any proportion.

[0013] As a preferred technical solution of the present invention, the illumination intensity of the red light supplement in step 7 is consistent with the basic illumination intensity, and a red LED lamp is used as the light source.

[0014] As a preferred technical solution of the present invention, the environmental control in step 8 further includes: testing the humidity of the cultivation substrate every 7 days, and watering in time when the substrate water holding capacity is lower than 40%, with watering based on the substrate being moist but without water accumulation.

[0015] As a preferred technical solution of the present invention, the vitamin C content of strawberry fruits treated by the method is increased by more than 30% compared with conventional cultivation, while the soluble solids content is increased by 1.5-2.0 percentage points.

[0016] As a preferred technical solution of the present invention, the method is applicable to various strawberry cultivation modes such as greenhouse cultivation, substrate pot cultivation, and soilless cultivation.

[0017] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention induces the activity of key enzymes for vitamin C synthesis in plant leaves through blue light pretreatment during the seedling stage, laying a physiological foundation for nutrient synthesis in the subsequent fruit stage; the special nutrient solution during the growth period precisely matches the nutritional needs of strawberries, supplementing the precursors and coenzymes required for vitamin C synthesis, opening up nutrient conversion pathways, and reducing nutrient loss; the exogenous regulator during the fruit enlargement period acts directly on the fruit, both supplementing the raw materials for synthesis and reducing the degradation rate of vitamin C through antioxidant components, achieving a dual benefit of promoting synthesis and preventing decomposition.

[0018] While increasing vitamin C content, this method simultaneously improves the flavor, appearance, and storage performance of the fruit. Red light supplementation during the ripening period promotes sugar accumulation and color formation in the fruit, and combined with nutritional regulation, enhances sweetness and aroma. Exogenous calcium strengthens the cell walls of the fruit, reducing damage during harvesting and transportation, and extending shelf life. Comprehensive environmental management maintains healthy plant growth, reduces pests and diseases, ensures a smooth fruit appearance and high individual fruit weight, and comprehensively improves commercial competitiveness.

[0019] This method is suitable for various strawberry growing scenarios, including greenhouses, hydroponics, and home potted plants. The control measures at each stage can be flexibly adjusted according to actual conditions: light control can be achieved by combining natural light and supplemental lighting, and nutrient solution and exogenous regulators can be applied by various methods such as irrigation, drip irrigation, or spraying. No complicated special equipment is required, which is convenient for large-scale promotion and home operation.

[0020] This method focuses on environmental control and nutritional intervention, without relying on chemical hormones or highly toxic pesticides. The special nutrient solution and exogenous regulators all use natural or low-toxicity ingredients, avoiding the risk of chemical residues in the fruit. Substrate sterilization and refined plant management reduce the occurrence of pests and diseases and reduce the amount of pesticides used, which is in line with the development direction of green ecological agriculture. The strawberries produced are more in line with the market demand for high quality, safety and health. Attached image description: Figure 1 A schematic flowchart of the process steps provided for this invention; Figure 2 A schematic block diagram of the illumination control parameters provided by the present invention; Figure 3 This is a schematic diagram of the cultivation substrate and nutrient management parameters provided by the present invention; Figure 4 This is a schematic diagram of the exogenous regulator formulation and spraying parameters provided by the present invention; Figure 5 This is a schematic diagram of the environmental and plant management parameters provided by the present invention. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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 specific implementations of the present invention and are not limited to all embodiments.

[0022] Therefore, the following detailed description of embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely illustrates some embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0023] It should be noted that, in the absence of conflict, the embodiments and features and technical solutions in the embodiments of the present invention can be combined with each other. It should be noted that similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0024] Example 1: Application of strawberry greenhouse cultivation Test materials Strawberry seedlings (three-leaf stage, free from pests and diseases, with well-developed root system), peat moss, vermiculite, well-rotted sheep manure, LED blue light lamps (wavelength 455nm), LED red light lamps (wavelength 630nm), special nutrient solution raw materials, exogenous regulator raw materials, etc.

[0025] Test methods Strictly follow the eight steps described in claim 1: Seedling selection: 200 strawberry seedlings with a height of 8-10cm, three leaves and one bud, dark green leaves, white roots and well-developed fibrous roots were selected and randomly divided into an experimental group and a control group, with 100 seedlings in each group.

[0026] Blue light pretreatment: The experimental group seedlings were placed in a smart light cultivation rack and exposed to light for 15 hours a day (natural light + LED supplemental light) with a total light intensity of 28,000 lux; from 9:00 to 11:00 in the morning, 20% intensity blue light (5,600 lux) was added for 8 consecutive days; the control group was provided with only natural light, and the daily light duration varied naturally with the season.

[0027] Substrate preparation: Peat moss, vermiculite, and well-rotted sheep manure are mixed in a volume ratio of 5:3:2, the pH is adjusted to 6.0, sterilized at 121℃ for 25 minutes, and after cooling, it is placed into a 15cm×20cm cultivation pot.

[0028] Seedling transplanting: The pretreated seedlings of the experimental group and the control group were transplanted into cultivation pots, one seedling per pot, at a planting depth of 3cm. After watering thoroughly, the seedlings were placed in the greenhouse.

[0029] Rhizosphere nutrient regulation: Starting 10 days after transplanting, the experimental group was treated with a special nutrient solution every 15 days. The formula was: calcium nitrate 320 mg / L, potassium nitrate 220 mg / L, ammonium dihydrogen phosphate 90 mg / L, magnesium sulfate 110 mg / L, boric acid 0.6 mg / L, manganese sulfate 0.4 mg / L, zinc fertilizer 0.25 mg / L, L-cysteine ​​0.8 mg / L, and vitamin B6 0.4 mg / L. 250 ml was applied to each plant each time, for a total of 3 applications. The control group was treated with an equal amount of conventional compound fertilizer solution (NPK=15-15-15, concentration 1000 mg / L) every 15 days.

[0030] Exogenous regulation: When the fruit diameter of the experimental group reached about 1.0 cm, an exogenous regulator was sprayed every 7 days. The formula was L-galactose 220 mg / L, tea polyphenols 60 mg / L, and calcium chloride 120 mg / L. The spraying was repeated twice, and the spraying time was from 4:30 pm to 5:30 pm. The control group was sprayed with an equal amount of water.

[0031] Red light supplementation: During the fruit color-changing period, the experimental group received 13 hours of light per day (natural greenhouse light + LED supplemental light), with a total light intensity of 22,000 lux; from 5:00 pm to 7:00 pm, 2 hours of red light (intensity 22,000 lux) were added; the control group maintained natural greenhouse light.

[0032] Environmental control: The daytime temperature in the greenhouse is controlled at 22-24℃, and the nighttime temperature at 10-12℃, with an air humidity of about 65%. Every 10 days, old and diseased leaves are removed, and each plant retains 5-6 functional leaves. Every 7 days, the substrate moisture is checked, and when the water holding capacity is lower than 40%, water is added until the water holding capacity is 60%.

[0033] Test results After harvesting, 30 mature fruits were randomly selected from both the experimental and control groups, and their nutritional indicators were tested. The vitamin C content of strawberries in the experimental group was 93.2 mg / 100g, while that in the control group was 61.5 mg / 100g, representing a 51.5% increase in vitamin C content compared to the control group. The soluble solids content in the experimental group was 11.4%, while that in the control group was 9.3%, representing an increase of 22.6%. The average weight of a single fruit in the experimental group was 28.6g, while that in the control group was 25.2g, representing an increase of 13.5%. The shelf life (time to maintain flavor at room temperature) of the fruit in the experimental group was 3.2 days, while that in the control group was 2.1 days, representing a 52.4% extension.

[0034] Example 2: Application of hydroponics in strawberry cultivation Test materials Strawberry seedlings (three-leaf stage), rock wool cultivation substrate, LED blue light (wavelength 460nm), LED red light (wavelength 640nm), special nutrient solution, exogenous regulators, etc., are grown in soilless cultivation facilities.

[0035] Test methods Seedling screening: 120 healthy seedlings were selected and divided into an experimental group and a control group of 60 seedlings each.

[0036] Blue light pretreatment: The experimental group received 14 hours of light per day with a total intensity of 25,000 lux, and was supplemented with 15% intensity blue light (3,750 lux) from 8:00 to 10:00 am for 7 consecutive days; the control group received natural light.

[0037] Substrate preparation: Use sterile rock wool blocks as the cultivation substrate, adjust the pH to 5.8, and place them in a soilless cultivation trough.

[0038] Transplanting and planting: Transplant the seedlings to the rock wool blocks, spacing each plant 25cm apart, and water thoroughly to settle the roots.

[0039] Nutritional regulation: Starting 10 days after transplanting, the experimental group was drip-irrigated with a special nutrient solution every 15 days. The formula was: calcium nitrate 300mg / L, potassium nitrate 200mg / L, ammonium dihydrogen phosphate 80mg / L, magnesium sulfate 100mg / L, boric acid 0.5mg / L, manganese sulfate 0.3mg / L, zinc fertilizer 0.2mg / L, L-cysteine ​​0.5mg / L, and vitamin B6 0.3mg / L. Each plant was drip-irrigated with 200ml each time. The control group was drip-irrigated with the same amount of conventional hydroponics nutrient solution.

[0040] Exogenous regulation: When the fruit diameter was 0.9 cm, the experimental group was sprayed with exogenous regulators (L-gulonic acid-1,4-lactone 200 mg / L, tea polyphenols 50 mg / L, calcium chloride 100 mg / L) every 7 days for 3 consecutive times; the control group was sprayed with water.

[0041] Red light supplementation: At the beginning of the color change period, the experimental group received 12 hours of light per day at an intensity of 20,000 lux, with 3 hours of supplemental red light from 5:00 pm to 8:00 pm; the control group received natural light.

[0042] Environmental control: The daytime temperature in the soilless cultivation facility should be 20-22℃, the nighttime temperature should be 8-10℃, and the air humidity should be 60%. Old leaves should be removed every 10 days, and the moisture of the rock wool substrate should be checked weekly and watered in a timely manner.

[0043] Experimental results: The vitamin C content of the fruit in the experimental group was 87.5 mg / 100g, while that in the control group was 59.8 mg / 100g, representing an increase of 46.3%. The soluble solids content in the experimental group was 10.9%, while that in the control group was 9.1%, representing an increase of 19.8%. The anthocyanin content of the fruit in the experimental group was 12.6 mg / 100g, while that in the control group was 9.2 mg / 100g, representing an increase of 37.0%.

[0044] Example 3: Application of strawberry potted plants Test materials Strawberry seedlings (three-leaf stage), potting substrate (peat moss: vermiculite: well-rotted sheep manure = 5:3:2), household LED supplemental lighting (with blue and red light modules), special nutrient solution, exogenous growth regulators, etc.

[0045] Test methods Seedling screening: 80 healthy seedlings were selected and divided into an experimental group and a control group of 40 seedlings each.

[0046] Blue light pretreatment: The experimental group received 16 hours of light per day with a total intensity of 30,000 lux, and was supplemented with 18% intensity blue light (5,400 lux) from 10:00 am to 12:00 pm for 10 consecutive days; the control group received natural indoor light.

[0047] Substrate preparation: The pH of the mixed substrate was adjusted to 6.2, sterilized, and then filled into 20cm diameter pots.

[0048] Transplanting and planting: Transplant one plant per pot at a depth of 2.5cm and water thoroughly to settle the roots.

[0049] Nutritional regulation: Starting 10 days after transplanting, the experimental group was irrigated with a special nutrient solution every 15 days. The formula was: calcium nitrate 350mg / L, potassium nitrate 250mg / L, ammonium dihydrogen phosphate 100mg / L, magnesium sulfate 120mg / L, boric acid 0.8mg / L, manganese sulfate 0.5mg / L, zinc fertilizer 0.3mg / L, L-cysteine ​​1.0mg / L, and vitamin B6 0.5mg / L. Each plant was irrigated with 300ml each time. The control group was irrigated with an equal amount of water and ordinary compound fertilizer.

[0050] Exogenous regulation: When the fruit diameter was 1.2 cm, the experimental group was sprayed with an exogenous regulator (250 mg / L of L-galactose + L-gulonic acid-1,4-lactone mixture, 80 mg / L of tea polyphenols, and 150 mg / L of calcium chloride) for two consecutive times; the control group was sprayed with water.

[0051] Red light supplementation: At the beginning of the color change period, the experimental group received 14 hours of light per day at an intensity of 25,000 lux, with 2 hours of supplemental red light from 6:00 pm to 8:00 pm; the control group received natural light.

[0052] Environmental management: Indoor temperature 23-25℃ during the day and 11-12℃ at night, air humidity 70%; remove old leaves every 10 days, water 1-2 times a week to keep the substrate moist.

[0053] Test results The vitamin C content of the fruit in the experimental group was 90.1 mg / 100g, while that in the control group was 62.3 mg / 100g, representing an increase of 44.6%. The soluble solids content in the experimental group was 11.1%, while that in the control group was 9.4%, representing an increase of 18.1%. The fruit firmness in the experimental group was 0.52 kg / cm². 2 The control group had a concentration of 0.41 kg / cm². 2 This represents an increase of 26.8%.

[0054] Comparative Example A control group was established using conventional cultivation methods. This group received no blue light pretreatment, no application of specialized nutrient solution, no exogenous regulation, and no red light supplementation; only conventional watering, fertilization, and light management were used. The results showed that the vitamin C content of strawberry fruits in the control group was only 58-63 mg / 100g, significantly lower than the 87.5-93.2 mg / 100g in the experimental groups. Furthermore, the fruit flavor, single fruit weight, and shelf life were all inferior to those in the experimental groups.

[0055] The above embodiments are only used to illustrate the present invention and are not intended to limit the technical solutions described herein. Although the present invention has been described in detail with reference to the above embodiments, the present invention is not limited to the specific embodiments described above. Therefore, any modifications or equivalent substitutions to the present invention, as well as all technical solutions and improvements that do not depart from the spirit and scope of the invention, are covered within the scope of the claims of the present invention.

Claims

1. A method for increasing the vitamin C content of strawberry fruit, characterized in that, Includes the following steps: Step 1: Seedling selection during the seedling stage: Select strawberry seedlings that are at the three-leaf-one-heart stage, free from pests and diseases, with dark green leaves and well-developed root systems; Step 2, Blue light pretreatment during seedling stage: The selected seedlings are subjected to light treatment, providing 14-16 hours of composite light with an intensity of 25,000-30,000 lux per day. From 8:00 am to 12:00 pm, supplement with blue light accounting for 15%-20% of the total light intensity with a wavelength of 450-470 nm. The treatment is carried out continuously for 7-10 days. Step 3, Preparation of cultivation substrate: Mix peat moss, vermiculite, and well-rotted sheep manure in a volume ratio of 5:3:2, adjust the pH value of the substrate to 5.5-6.5, sterilize at high temperature, and then put it into the cultivation container; Step 4, Seedling Transplanting: Transplant the pretreated strawberry seedlings into the prepared cultivation substrate. The planting depth of each seedling should be such that the roots are completely buried in the substrate and the heart leaves are exposed above the surface. Water thoroughly after transplanting. Step 5, Root zone nutrition regulation during the growth period: Starting 10 days after transplanting, apply a special nutrient solution every 15 days, 200-300ml per plant each time, until the fruit enlargement period. Step 6, exogenous regulation during fruit enlargement: When the diameter of strawberry fruit reaches 0.8-1.2cm, spray an exogenous regulator every 7 days for 2-3 consecutive times; the exogenous regulator formula is: L-ascorbic acid precursor 200-250mg / L, tea polyphenols 50-80mg / L, calcium chloride 100-150mg / L, and water as the solvent; Step 7, Red light supplementation during ripening: After the strawberry fruit enters the color-changing stage, adjust the light duration to 12-14 hours per day and the intensity to 20,000-25,000 lux. At the same time, supplement with red light with a wavelength of 620-660nm for 2-3 hours every afternoon from 5:00 to 8:00 until the fruit ripens. Step 8, Environmental Management during the Growing Period: Maintain a daytime temperature of 20-25℃ and a nighttime temperature of 8-12℃, with an air humidity of 60%-70% throughout the growing period. Remove old leaves, diseased leaves, and lateral buds every 10 days to ensure good ventilation and light penetration for the plants.

2. The method for increasing the vitamin C content of strawberry fruit according to claim 1, characterized in that, The composite lighting mentioned in step 2 is a combination of natural light and LED fill light, with the LED fill light providing the full light intensity on cloudy or rainy days.

3. The method for increasing the vitamin C content of strawberry fruit according to claim 1, characterized in that, The high-temperature sterilization mentioned in step 3 involves sterilizing the mixed substrate at 121°C for 20-30 minutes, and then cooling it for later use.

4. The method for increasing the vitamin C content of strawberry fruit according to claim 1, characterized in that, The special nutrient solution mentioned in step 5 should be prepared and used immediately. The formula of the special nutrient solution is as follows: calcium nitrate 300-350 mg / L, potassium nitrate 200-250 mg / L, ammonium dihydrogen phosphate 80-100 mg / L, magnesium sulfate 100-120 mg / L, boric acid 0.5-0.8 mg / L, manganese sulfate 0.3-0.5 mg / L, zinc fertilizer 0.2-0.3 mg / L, L-cysteine ​​0.5-1.0 mg / L, and vitamin B6 0.3-0.5 mg / L. When preparing the solution, first dissolve the macro-elements, then add the micro-elements, L-cysteine, and vitamin B6 in sequence, stir evenly, and adjust the pH to 5.5-6.

0.

5. The method for increasing the vitamin C content of strawberry fruit according to claim 1, characterized in that, The exogenous regulator mentioned in step 6 should be sprayed before 9:00 am or after 4:00 pm. The spraying should be done until the underside of the leaves and the surface of the fruit are evenly moistened, avoiding spraying during the midday sun.

6. The method for increasing the vitamin C content of strawberry fruit according to claim 1, characterized in that, The L-ascorbic acid precursor mentioned in step 6 is one or a mixture of two of L-galactose and L-gulonic acid-1,4-lactone in any proportion.

7. The method for increasing the vitamin C content of strawberry fruit according to claim 1, characterized in that, The intensity of the supplementary red light in step 7 is the same as the basic light intensity, and a red LED light is used as the light source.

8. The method for increasing the vitamin C content of strawberry fruit according to claim 1, characterized in that, The environmental control described in step 8 also includes: testing the humidity of the cultivation substrate every 7 days, and watering promptly when the substrate water content is below 40%, ensuring the substrate is moist but without standing water.

9. The method for increasing the vitamin C content of strawberry fruit according to claim 1, characterized in that, The vitamin C content of strawberry fruits treated by the method is increased by more than 30% compared with conventional cultivation, while the soluble solids content is increased by 1.5-2.0 percentage points.

10. A method for increasing the vitamin C content of strawberry fruit according to any one of claims 1-9, characterized in that, The method is applicable to various strawberry cultivation modes, including greenhouse cultivation, substrate pot cultivation, and soilless cultivation.

Images