Overwintering seedling raising method for improving low temperature resistance of peppers

Abstract

The invention relates to the technical field of agricultural planting, in particular to an overwintering seedling raising method for improving the low temperature resistance of chilies. The invention provides an overwintering seedling raising method for improving the low temperature resistance of peppers. The method comprises the following steps: building a three-layer shed frame, covering a film, and digging a seedbed in the shed; pepper seeds are sowed into the hole tray, then film mulching is conducted, and the hole tray is placed on a seedbed for seedling emergence cultivation; after pepper seedlings emerge, removing the film and continuously carrying out seedling emergence cultivation; when two true leaves grow on the pepper, the pepper is transplanted into a nutrition pot, the nutrition pot is placed on a seedbed for seedling separation cultivation, and diethyl aminoethyl hexanoate is sprayed when the temperature in the greenhouse reaches 8-10 DEG C. According to the method, the development of pepper seedlings is promoted, the plant metabolism is adjusted and the adaptability to the adverse environment is enhanced by adopting a segmented seedling raising mode of combining hole trays with nutrition bowls; according to the method, physical measures such as an electric heating wire and a warming furnace are not needed for heating, energy is saved, the low-temperature stress resistance of the pepper seedlings is improved, and growth and development of the seedlings are promoted.

Description

Technical Field

[0001] This invention relates to the field of agricultural planting technology, and in particular to a method for overwintering seedling cultivation to improve the low-temperature resistance of chili peppers. Background Technology

[0002] Seedling cultivation is a crucial step in chili pepper production. Developing robust seedlings is essential for high-yield, high-quality chili peppers and is key to achieving efficient chili pepper production. Chili pepper seedling cultivation is a highly technical task requiring meticulous management. This is especially true for autumn-sown chili peppers undergoing overwintering cultivation, which spans two years and takes place during the coldest season of the year, presenting significant technical challenges and management requirements. The core objectives of seedling cultivation are to maintain warmth, increase light exposure, prevent disease, and promote growth, ensuring that chili pepper seedlings thrive in low-temperature environments and reach robust seedling standards. This guarantees rapid seedling establishment after early spring transplanting, early flowering and fruiting, and ultimately, higher economic benefits.

[0003] In winter seedling production, the commonly used seedling raising methods are plug tray seedling raising or nutrient pot seedling raising. Plug tray seedling raising has advantages such as lower cost, labor saving, and less effort. When sowing and raising seedlings in early spring, the temperature gradually rises, and using plug tray seedling raising is beneficial for transplanting peppers into open fields. Using nutrient pot seedling raising provides more space for individual pepper seedlings to grow, which can better promote the development of lateral roots and cultivate strong seedlings. For overwintering seedling raising, sowing is generally done in autumn, and transplanting is carried out in greenhouses or other facilities in early spring of the following year. Due to the long seedling raising period, the low temperature and adverse conditions in winter affect the growth of pepper seedlings. The technical requirements for the management of the entire seedling period are relatively high. Using plug tray seedling raising throughout the entire process cannot provide long-term nutrients, and multiple replenishments of water and nutrients are required, increasing the difficulty of seedling management.

[0004] Therefore, in the process of overwintering seedling cultivation of chili peppers, there is an urgent need for a simple and energy-saving method to improve the low-temperature resistance of chili peppers. Summary of the Invention

[0005] The purpose of this invention is to provide a method for overwintering seedling cultivation that improves the low-temperature resistance of chili peppers. This method uses a segmented seedling cultivation method combining plug trays and nutrient pots to promote the development of chili pepper seedlings, adjust plant metabolism, and enhance adaptability to adverse environments. The use of multi-layer greenhouse film and spraying growth regulators not only improves the low-temperature resistance of chili peppers and produces robust seedlings, but also saves energy.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a method for overwintering seedling cultivation to improve the low-temperature resistance of chili peppers, comprising the following steps: (1) Build a three-layer shed, cover it with film, and dig seedbeds inside the shed; (2) After sowing the chili seeds into the seedling trays, cover them with film and place the seedling trays on the seedbed for seedling cultivation; after the chili seedlings emerge, remove the film and continue seedling cultivation; (3) When the peppers have grown to 2 true leaves, transplant them into nutrient pots and place the nutrient pots on the seedbed for seedling cultivation; (4) During the seedling cultivation process, spray amino acid ester when the temperature inside the innermost layer of the greenhouse reaches 8~10℃.

[0007] Preferably, the three-layer shed includes a large shed, a medium shed, and a small arched shed; The greenhouse is 8-10m wide and 40-50m long; The width of the central shed is 6-8m and the length is 25-35m; The small arched shed is 1.2-1.4m wide and 10-15m long.

[0008] Preferably, the seedbed is 1.2-1.4m wide, 10-15m long, and 5-10cm deep; The seedbed needs to be covered with black non-woven fabric.

[0009] Preferably, in step (2), the chili seeds need to be soaked and germinated before sowing; The soaking temperature is 55~60℃; the soaking time is 5~7 hours; The germination temperature is 26~30℃; the germination time is 40~56h.

[0010] Preferably, in step (2), the seeding depth is 0.5~1cm.

[0011] Preferably, in step (3), the nutrient pot contains mixed soil; the mixed soil includes the following mass percentages of soil: 55-65% fine field soil, 25-35% nutrient soil, and 5-15% bio-organic fertilizer.

[0012] Preferably, in step (3), carbendazim is also added to the nutrient pot; the amount of carbendazim added is... .

[0013] Preferably, in step (4), the concentration of the amino ester is 12~18 mg / L.

[0014] Preferably, during the seedling cultivation process, the daytime temperature of the small arched shed is 20~26℃ and the nighttime temperature is 15~18℃; during the seedling division cultivation process, the daytime temperature of the small arched shed is 18~25℃ and the nighttime temperature is 8~14℃.

[0015] Beneficial effects: This invention provides a method for improving the low-temperature tolerance of chili peppers during overwintering seedling cultivation. The overwintering process of chili pepper seedlings is lengthy and often encounters adverse low-temperature conditions that affect seedling growth. This invention addresses this by laying black non-woven fabric above the seedbed, using multi-layered greenhouse film for insulation, and employing seedling trays during sowing. This fully utilizes the advantages of high space utilization and convenient unified management of seedling trays and substrate cultivation. When the chili pepper seedlings reach the "two leaves and one bud" stage, they are transplanted into nutrient pots. When the temperature inside the seedling shed drops to a certain level, growth regulators are sprayed to enhance the seedlings' low-temperature tolerance and improve their cold resistance. This method uses a segmented seedling cultivation approach combining seedling trays and nutrient pots to promote chili pepper seedling development, regulate plant metabolism, and enhance adaptability to adverse environments. This method eliminates the need for physical heating methods such as electric heating wires and heaters, saving energy and reducing the number of water and fertilizer management operations required for seedling tray cultivation. It also ensures the necessary nutrients for the chili pepper seedlings, resulting in robust seedlings that reach the budding stage and are ready for transplanting, resulting in excellent seedling cultivation outcomes. The malondialdehyde (MDA) content of the pepper seedlings cultivated by this invention was significantly reduced by 45.42% compared with the treatment of spraying with water, the plant height was significantly increased by 25.14% compared with the treatment of spraying with water, and the diameter increased by 8.33%. This improved the stress resistance of pepper seedlings and promoted seedling growth, resulting in good seedling cultivation effect. Attached Figure Description

[0016] Figure 1 The effects of different treatment groups on the chlorophyll content of pepper seedlings; Figure 2 The effect of different treatment groups on the superoxide anion content of pepper seedlings; Figure 3 The effects of different treatment groups on reactive oxygen species in pepper seedlings; Figure 4 The effect of different treatment groups on malondialdehyde content in pepper seedlings; Figure 5 The effects of different treatment groups on the height of chili seedlings; Figure 6 The effect of different treatment groups on the stem diameter of chili seedlings. Detailed Implementation

[0017] This invention provides a method for overwintering seedling cultivation to improve the low-temperature resistance of chili peppers, comprising the following steps: (1) Build a three-layer shed, cover it with film, and dig seedbeds inside the shed; (2) After sowing the chili seeds into the seedling trays, cover them with film and place the seedling trays on the seedbed for seedling cultivation; after the chili seedlings emerge, remove the film and continue seedling cultivation; (3) When the peppers have grown to 2 true leaves, transplant them into nutrient pots and place the nutrient pots on the seedbed for seedling cultivation; (4) During the seedling cultivation process, spray amino acid ester when the temperature inside the innermost layer of the greenhouse reaches 8~10℃.

[0018] In this invention, the three-layer greenhouse includes a large greenhouse, a medium greenhouse, and a small arched greenhouse; a medium greenhouse is built inside the large greenhouse, and a small arched greenhouse is built inside the medium greenhouse, using three layers of greenhouse film for heat preservation and overwintering seedling cultivation; The greenhouse is 8-10m wide, preferably 8.5-9.5m, more preferably 9m, and 40-50m long, preferably 43-47m, more preferably 45m, and is completely covered with greenhouse film; The width of the greenhouse is 6-8m, preferably 6.5-7.5m, more preferably 7m, and the length is 25-35m, preferably 28-32m, more preferably 30m, and it is also covered with greenhouse film; The small arched shed has a width of 1.2~1.4m, preferably 1.25~1.35m, more preferably 1.3m, and a length of 10~15m, preferably 12~13m, more preferably 12.5m, and is also covered with a plastic film; Dig a seedbed in the greenhouse. The width of the seedbed is preferably 1.25-1.35m, more preferably 1.3m, the length is 10-15m, preferably 12-13m, more preferably 12.5m, and the depth is 5-10cm, preferably 7-8cm, more preferably 7.5cm. The seedbed needs to be covered with black non-woven fabric to prevent the seedlings from taking root in the soil and to prevent heat loss.

[0019] In this invention, in step (2), the chili seeds need to be soaked (to allow the chili seeds to fully absorb water) and germinated before sowing; The soaking temperature is 55~60℃, preferably 57~58℃, and more preferably 57.5℃; the soaking time is 5~7h, preferably 5.5~6.5h, and more preferably 6h. The method for germination is as follows: after soaking, the seeds are wrapped in a damp towel and placed in an incubator for germination. The seeds are sown when they show white sprouts. The germination temperature is 26~30℃, preferably 27~29℃, and more preferably 28℃; the germination time is 40~56h, preferably 44~52h, and more preferably 48h.

[0020] In this invention, in step (2), the specific steps of sowing are as follows: using nutrient soil with ≥50% organic matter as substrate, placing the substrate in a 72-cell tray, thoroughly watering the tray before sowing, sowing one chili seed in each cell, and sowing at a depth of 0.5~1cm, preferably 0.7~0.8cm, and more preferably 0.75cm. The purpose of the coating is to keep the room warm and moist.

[0021] In this invention, during the seedling cultivation process, the daytime temperature of the small arched greenhouse is 20-26℃, preferably 22-24℃, and more preferably 23℃, while the nighttime temperature is 15-18℃, preferably 16-17℃, and more preferably 16.5℃. If the temperature inside the small arched greenhouse exceeds 30℃, the sides of the small arched greenhouse film and the entrance of the middle greenhouse are opened for ventilation and cooling to prevent excessive growth and to "harden the seedlings." In the evening, the films of the middle and small arched greenhouses are lowered to retain heat. At this time, no watering or fertilization is applied; the focus is on controlling the seedlings and promoting root development to ensure rapid root development of the seedlings, laying a solid foundation for later transplanting and overwintering seedling cultivation.

[0022] In this invention, the sowing time is October. If the sowing time is too early, the seedlings will be too old and become "small and old seedlings"; if the sowing time is too late, it will affect the transplanting and marketability in the early spring of the following year.

[0023] In this invention, in step (3), the nutrient pot contains a mixed soil; the mixed soil comprises the following soil components by mass percentage: The fine soil content is 55-65%, preferably 58-62%, and even more preferably 60%; The nutrient soil content is 25-35%, preferably 28-32%, and more preferably 30%; The bio-organic fertilizer contains 5-15%, preferably 8-12%, and even more preferably 10%; The size of the nutrient pot is 10cm×10cm; The specific steps for transplanting the chili seedlings into the nutrient pots are as follows: After transplanting the chili seedlings into the nutrient pots, fill the pots with mixed soil until the roots of the chili seedlings are buried in the mixed soil, while the cotyledons are exposed above the nutrient pots, and then water them thoroughly.

[0024] In this invention, in step (3), carbendazim needs to be added to the nutrient pot to prevent seedling diseases; the amount of carbendazim added is... Preferred Further optimized .

[0025] In this invention, in step (4), the concentration of the amino acid ester is 12~18 mg / L; the spraying method of the amino acid ester is: spray the amino acid ester evenly onto the front and back of the chili leaves to cover the water droplets; enhance the seedlings' resistance to low temperature, improve the seedlings' cold resistance, and promote growth and development.

[0026] In this invention, during the seedling cultivation process, the daytime temperature of the small arched shed is 18~25℃, preferably 20~23℃, and more preferably 21.5℃. At night, the insulation is strengthened and the nighttime temperature is 8~14℃. If a cold wave occurs, a layer of white non-woven fabric is covered on the small arched shed film for insulation.

[0027] The seedling cultivation process also includes temperature management, water and fertilizer management, ventilation management, and pest and disease management; Temperature management focuses on heat preservation and light enhancement to promote rapid root development. A multi-layered covering method is used: a large greenhouse film + a medium greenhouse film (with a medium greenhouse built inside the large greenhouse) + a small arched greenhouse film for heat preservation, while maintaining the temperature inside the small arched greenhouse. Water and fertilizer management: In terms of water and fertilizer management, it is better to keep the soil dry than wet. Preheat the water in the bucket in the greenhouse for 1-2 days in advance to prevent cold water from damaging the roots. Follow the principle of "don't water if it's not dry, and water thoroughly when you do water". Water in the morning on sunny days to avoid watering in the afternoon or evening, which will increase humidity and lower the soil temperature. Seedlings raised in nutrient pots generally do not need to be top-dressed during the seedling stage. Ventilation Management: High humidity (≥80%) is a major cause of seedling diseases (damping-off, seedling blight); ventilation can not only lower the temperature, but also reduce humidity and the occurrence of diseases. Depending on the weather, in the morning, open 1-2 small ventilation openings on both sides of the large arched greenhouse, open the entrance of the medium greenhouse film, and open the small arched greenhouse film through the small ventilation openings to remove moisture. In the evening, lower the films of the large and medium greenhouses, and cover the small arched greenhouse film to retain heat. Pest and disease management: Prevention is the main focus of pest and disease control. The main diseases of chili seedlings are damping-off, seedling blight, and gray mold. In terms of pests, there are some pests in the early stage of seedling cultivation, but fewer pests in the later stage of seedling cultivation due to the lower winter temperature. The main pests are aphids, whiteflies, and thrips. Control measures include: 1. Improving the temperature and humidity inside the greenhouse by strengthening ventilation; 2. Hanging yellow sticky traps inside the greenhouse to attract and kill aphids and whiteflies; 3. Chemical control, with priority given to smoke agents (45% carbendazim smoke agent) at a dosage of 200-250g / acre to control diseases, while avoiding increasing humidity.

[0028] The preferred dosage of the fumigant is 220-230 g / mu, and more preferably 225 g / mu.

[0029] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0030] In the embodiments and experimental examples of this invention, the tested chili pepper variety was Xiangyan No. 15, bred by Hunan Xiangyan Seed Industry Co., Ltd.; naphthaleneacetic acid (NAA) and amino acid ester (DA-6) were purchased from Sichuan Runer Technology Co., Ltd.; sodium nitrophenolate (CSN) was purchased from Xuhua Chemical Industry (Zhangzhou) Co., Ltd.; bio-organic fertilizer (organic matter ≥50%) was purchased from Qingdao Kangtuwodi Agricultural Technology Co., Ltd.; substrate (organic matter ≥50%, also used as substrate) was purchased from Huai'an Zhonghe Agricultural Technology Development Co., Ltd.; carbendazim was in the form of 50% wettable powder and was purchased from Anhui Huaxing Chemical Co., Ltd. Example 1: A method for overwintering seedlings to improve the low-temperature tolerance of chili peppers. (1) The experiment was conducted in Huanggang Modern Agricultural Science and Technology Demonstration Park from October 2025 to February 2026. A greenhouse with a width of 10m and a length of 40m was built and covered with a greenhouse film. Inside the greenhouse, a medium greenhouse with a width of 8m and a length of 30m was built with steel pipes and covered with a greenhouse film. Seedbeds were dug in the medium greenhouse. The seedbeds were 1.2m wide, 15m long and 8cm deep. After the seedbed ground was leveled, a layer of black non-woven fabric was laid on top to prevent the seedlings from taking root in the soil and heat loss. A small arched greenhouse with a width of 1.2m and a length of 15m was built above the seedbed with a glass fiber arched greenhouse frame and covered with a greenhouse film. (2) On October 14, 2025, chili seeds were soaked in 60℃ water for 6 hours to allow them to fully absorb water. The soaked seeds were then wrapped in a damp towel and placed in an incubator at 28℃ for 48 hours to germinate. After the seeds turned white, they were sown into 75-cell trays filled with substrate. Before sowing, the trays were thoroughly watered. One chili seed was sown in each cell. After sowing, the trays were covered with a 1cm layer of substrate, and a thin film was placed on top for insulation and moisture retention. The seedling trays were then placed in the seedbed for further processing. After the chili peppers emerge, promptly remove the plastic film above the seedling trays and continue to cover them with the film of the small arched greenhouse to retain warmth and moisture. During this period, maintain the temperature inside the small arched greenhouse at 20-26℃ during the day and 15-18℃ at night. If the temperature exceeds 30℃, open the sides of the small arched greenhouse film and the entrance of the middle greenhouse for ventilation and cooling to prevent excessive growth and to "harden the seedlings." In the evening, lower the films of the middle and small arched greenhouses to retain warmth. Do not water or apply fertilizer at this time; focus on controlling the sapling growth and promoting root development to ensure rapid root development of the seedlings and lay a solid foundation for later transplanting and overwintering seedling cultivation. (3) When the chili seedlings have grown to 2 true leaves, transplant them into seedling pots (10cm×10cm). During the transplanting process, select strong seedlings and discard inferior seedlings, transplanting one seedling per pot; the seedling pots contain a uniformly mixed soil, which includes 60% sieved field soil, 30% nutrient soil, and 10% bio-organic fertilizer; add to the soil Use carbendazim to prevent seedling diseases; after transplanting the pepper seedlings, fill the nutrient pots with mixed soil, so that the roots of the seedlings are buried in the mixed soil and the cotyledons are exposed on the nutrient pots. Water thoroughly, place the nutrient pots on the seedbed for seedling cultivation, and continue to cover the small arched greenhouse film for heat preservation. (4) During the seedling cultivation process, when the temperature inside the innermost arched greenhouse reaches 8℃, spray with 15mg / L amino acid ester (December 16th), spraying until the front and back of the pepper leaves are evenly covered with mist-like water droplets. This enhances the seedlings' resistance to low temperatures, improves their cold resistance, and promotes growth and development; (5) Seedling management: Temperature management: Temperature management focuses on heat preservation and light enhancement to promote rapid root development; the temperature inside the small arched greenhouse is maintained at 18-25℃ during the day; heat preservation is strengthened at night, and a layer of white non-woven fabric is covered on the greenhouse film for heat preservation during cold waves; Water and fertilizer management: In terms of water and fertilizer management, it is better to keep the soil dry than wet. Preheat the water in a bucket in the greenhouse for 2 days in advance to prevent cold water from damaging the roots. Follow the principle of "don't water if it's not dry, and water thoroughly when you do water". Water in the morning on sunny days to avoid watering in the afternoon or evening, which will increase humidity and lower the soil temperature. Seedlings raised in nutrient pots generally do not need to be top-dressed during the seedling stage. Ventilation Management: High humidity (≥80%) is a major cause of seedling diseases (damping-off, seedling blight); ventilation can not only lower the temperature, but also reduce humidity and the occurrence of diseases. Depending on the weather, in the morning, moderately open 1-2 small ventilation openings on both sides of the large arched greenhouse, open the entrance of the medium greenhouse film, and open the small arched greenhouse film through the small ventilation openings to remove moisture. In the evening, lower the films of the large and medium greenhouses, and cover the small arched greenhouse film to retain heat. Pest and disease management: Prevention is the main focus of pest and disease control. The main diseases of chili seedlings are damping-off, seedling blight, and gray mold. In terms of pests, there are some pests in the early stage of seedling cultivation, but fewer pests in the later stage of seedling cultivation due to the lower winter temperature. The main pests are aphids, whiteflies, and thrips. Control measures include: 1. Improving the temperature and humidity inside the greenhouse by strengthening ventilation; 2. Hanging yellow sticky traps inside the greenhouse to kill aphids and whiteflies; 3. Chemical control, with priority given to smoke agents (45% chlorothalonil smoke agent) at a dosage of 225g / acre to control diseases, while avoiding increasing humidity.

[0031] Comparative Example 1 Referring to Example 1, the difference from the example is that in step (4), 15 mg / L amino acid ester is replaced with water, and the other steps are the same as in Example 1.

[0032] Comparative Example 2 Referring to Example 1, the difference from the example is that in step (4), 15 mg / L aminoethyl ester is replaced with 6 mg / L sodium nitrophenolate, and the other steps are the same as in Example 1.

[0033] Comparative Example 3 Referring to Example 1, the difference from the example is that in step (4), 15 mg / L aminoethyl ester is replaced with 50 mg / L naphthaleneacetic acid, and the other steps are the same as in Example 1.

[0034] Experimental Example 1: Chlorophyll Content Determination Chlorophyll can absorb and transfer energy for plant photosynthesis, and its content directly affects the normal growth and development of plants. The seedlings were cultivated using the methods described in Example 1 and Comparative Examples 1-3, with 15 seedlings in each treatment group and 3 replicates. Chlorophyll levels were measured three days after each group was sprayed with a growth regulator or water. Eight seedlings were measured per treatment per replicate. Results are as follows: Figure 1 As shown; The chlorophyll content was measured using a TYS-4N handheld chlorophyll meter manufactured by Beijing Zhongke Weihe. The chlorophyll content in the leaves was measured between 9:00 and 10:00 AM. During the measurement, the middle of the third fully unfolded true leaf (counting down from the growing point) of the pepper seedling was selected. The surface of the pepper leaf was gently wiped clean with a paper towel to remove moisture and dust. The leaf was then placed in the chlorophyll meter, ensuring it evenly covered the measurement area. The measurement was recorded after the instrument completed its measurement. Depend on Figure 1 It can be seen that the chlorophyll SPAD value of the Example 1 group was significantly increased by 14.23% compared with the Comparative Example 1, indicating that amino ester accelerated the photosynthetic rate of plants, increased the chlorophyll content in plants, and promoted the synthesis and accumulation of carbohydrates in plants; the SPAD values ​​of the Comparative Example 2 and Comparative Example 3 treatments increased by 5.02% and 0.42% respectively compared with the Comparative Example 1, indicating that the treatment enhanced the photosynthesis of leaves, but the difference from the Comparative Example 1 was not significant. Experiment Example 2: Measurement of Physiological Indicators Physiological and biochemical activities are fundamental processes in plant life. By measuring physiological activity indicators to reveal the life activity patterns of peppers under low-temperature conditions, we can delve deeper into the essence behind this phenomenon. Under low-temperature stress, a large number of free radicals accumulate in plant cells, inhibiting the activity of antioxidant enzymes (such as superoxide dismutase, catalase, and peroxidase), leading to the accumulation of reactive oxygen species (such as superoxide anions and hydrogen peroxide) in the plant. This initiates a chain reaction of membrane lipid peroxidation, producing malondialdehyde (MDA), which damages plant cells. This is a significant cause of stress-related damage. MDA is one of the main decomposition products of membrane lipid peroxidation and is an important indicator of the degree of cell membrane damage. Superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) are an interconnected antioxidant enzyme system that can scavenge accumulated reactive oxygen free radicals in cells, thereby inhibiting lipid peroxidation and reducing MDA production. SOD can catalyze the conversion of superoxide anions (… ) is converted into hydrogen peroxide ( Further removal of ROS, CAT, and POD will It breaks down into water and oxygen, working together to protect cells from oxidative damage; the resistance of plants to low temperature stress is related to the activity of SOD in their bodies, and SOD plays an important role in plants' response to abiotic stresses such as low temperature.

[0035] Soluble sugars (SS), soluble proteins (SP), and proline (Pro), as important osmotic regulators in plants, can maintain cell osmotic pressure and enhance cell water absorption and retention capacity under stress conditions. Higher levels of these substances result in higher free water content within plant cells, mitigating the damage from cell dehydration and improving plant resistance to low-temperature stress. Under low-temperature conditions, the amount of soluble substances in pepper plants increases, thus alleviating the damage caused by low-temperature stress. Therefore, a large number of osmotic regulators, such as SP, SS, and Pro, accumulate in plants to promote cell osmotic regulation. Simultaneously, the activity of protective enzymes also changes accordingly, protecting plants from low-temperature damage. The increase of these substances can reduce the degree of cell membrane lipid peroxidation, ensuring cell membrane integrity and thus reducing the harm of low-temperature stress to seedlings. This is an important regulatory mechanism for seedlings to cope with low-temperature stress. Under low-temperature stress, plants spontaneously initiate osmotic regulation to retain internal water. After measuring the chlorophyll content, select the 3rd to 4th true leaves from top to bottom for physiological index measurement: (1) Reactive oxygen species (ROS) content Determination of superoxide anion using the naphthylamine method ( Determination of hydrogen peroxide using the titanium sulfate method ( ), the result is as follows Figure 2 and Figure 3 As shown; Depend on Figure 2 It can be seen that the three treatments for superoxide anions ( The content of all samples was significantly different from that of Comparative Example 1, and the differences between the treatments in Example 1, Comparative Example 2, and Comparative Example 3 were also significant; among them, the treatments in Example 1 and Comparative Example 2... The contents were significantly reduced by 15.57% and 9.91% respectively compared with Comparative Example 1; Comparative Example 3 treatment The content was significantly increased by 19.34% compared to control example 1; Depend on Figure 3 It can be seen that the hydrogen peroxide in each treatment ( The content of all samples was significantly lower than that of Comparative Example 1; Example 1 treatment The content was significantly reduced by 38.01% compared with Comparative Example 1, and significantly reduced by 14.48% and 13.80% respectively compared with Comparative Example 2 and Comparative Example 3; there was no significant difference between Comparative Example 2 and Comparative Example 3. (3) Antioxidant enzyme activity Superoxide dismutase (SOD) was determined by nitroblue tetrazolium (NBT) photochemical reduction method, catalase (CAT) was determined by ammonium molybdate catalytic decomposition method, and peroxidase (POD) was determined by guaiacol method. The results are shown in Table 1. Table 1 Effects of different treatments on antioxidant enzyme activity in pepper seedlings As shown in Table 1, the SOD activity of the pepper seedlings treated in Example 1 was significantly reduced, decreasing by 11.80% compared to Comparative Example 1. The activities of CAT and POD in the treatment of Example 1 were higher than those in Comparative Example 1, but the difference was not significant. The SOD activity in the treatment of Comparative Example 2 was significantly increased, increasing by 58.91%, and the activities of CAT and POD were also significantly increased. The SOD activity of the pepper seedlings treated in Comparative Example 3 was significantly increased, with the largest increase, and there was no significant difference compared to the treatment of Comparative Example 2. The activities of CAT and POD in the treatment of Comparative Example 3 were greatly enhanced, and both were significantly different from other treatments.

[0036] (4) Malondialdehyde content The determination of malondialdehyde (MDA) by the thiobarbituric acid method yielded the following results: Figure 4 As shown; Depend on Figure 4 It can be seen that Comparative Example 1 had the highest MDA content; the MDA content of each treatment was significantly lower than that of Comparative Example 1, and the differences between treatments were significant; the MDA content of the treatment in Example 1 was the lowest, decreasing by 45.42% compared to Comparative Example 1; the MDA content of the treatments in Comparative Example 2 and Comparative Example 3 decreased by 24.42% and 8.59% respectively compared to Comparative Example 1; Based on the above four physiological indicators, SOD activity decreased and the activities of CAT and POD enzymes increased after treatment in Example 1; combined with the treatment in Example 1... , Both SOD and MDA content decreased significantly, indicating that the treatment in Example 1 promoted an excess SOD reaction and avoided the excessive production of SOD at low temperatures. This leads to an excess of CAT and POD scavenging capacity, thus exacerbating oxidative damage; in Comparative Example 2, the activities of the three antioxidant enzymes SOD, POD, and CAT in pepper seedlings were significantly increased and significantly decreased. The content of [specific ingredient] inhibited the process of membrane lipid peroxidation, reduced membrane system damage under low temperature stress, and thus reduced electrolyte leakage, which helped maintain the normal cell structure and physiological function of pepper seedlings; indicating that Comparative Example 2, this exogenous growth regulator activated the pepper seedlings' own antioxidant defense system to synergistically scavenge reactive oxygen species and reduce oxidative damage; Comparative Example 3 treatment The content decreased significantly. The content increased significantly, and the activities of the three antioxidant enzymes were significantly enhanced, which may be due to the intervention of the treatment in Comparative Example 3. As harmful substances that need to be quickly eliminated, they differentially altered the metabolic pathways and signaling pathways of different reactive oxygen species. Although the activity of antioxidant enzymes was activated and the induced antioxidant enzyme activity was strong, the initiation of the defense mechanism lagged behind the damage, and lipid peroxidation continued, ultimately leading to an increase in MDA accumulation. As a result, the MDA content was significantly lower than that of control 1 but higher than that of the other two treatments. After treatment with three different exogenous growth regulators, the MDA content in pepper seedling leaves decreased and the difference from the control was significant, indicating that these exogenous growth regulators all played a role in resisting low temperature stress.

[0037] (5) Content of osmotic adjustment substances Pro was determined by the ninhydrin method, SP was determined by the Coomassie Brilliant Blue G-250 method, and SS was determined by the 3,5-dinitrosalicylic acid (DNS) method. The results are shown in Table 2. Table 2 Effects of different treatments on the content of osmotic regulators in pepper seedlings Table 2 shows that the osmotic regulatory substances in the treatment of Example 1 were all lower than those in Comparative Example 1, with a significant difference in Pro content, which decreased by 10.14%. The pepper seedlings treated in Example 1 may have experienced a decrease in osmotic regulatory substances to varying degrees because the source ROS was effectively eliminated, reducing oxidative damage. Cells no longer needed to synthesize large amounts of proline and soluble sugars to maintain osmotic balance; MDA content decreased significantly, and membrane damage was reduced. It is also possible that a synergistic effect exists between signal-triggered accumulation of osmotic regulatory substances and the oxidative defense capacity provided by antioxidant enzymes, inducing other more efficient osmotic regulatory mechanisms. The specific mechanisms require further investigation. The cold resistance of pepper seedlings is jointly regulated by multiple osmotic regulatory substances and various protective enzymes. All indicators in Comparative Example 2 were significantly different from those in Comparative Example 1. Specifically, SS content decreased significantly, while SP and Pro content increased significantly, by 45.07% and 19.57% respectively compared to Comparative Example 1. Comparative Example 3 had the lowest SS content among all treatments, decreasing by 44.62% compared to Comparative Example 1, a significant decrease. The SP and Pro content in Comparative Example 3 were significantly higher than the control, and both indicators in Comparative Example 3 were significantly higher than in other treatments. Combined with the MDA content in these two treatments, it indicates that the treatment induced the synthesis of a new specific protective protein in pepper seedlings, and the increase in soluble protein is a result of adaptive gene expression. The treatments enhanced the chili seedlings' resistance to low-temperature damage and their ability to maintain cell structure and metabolism. Low temperature, as an environmental signal, triggers gene expression reprogramming in chili seedlings through exogenous growth regulator treatment, leading to the large-scale consumption of soluble sugars to synthesize more cold-resistant substances to adapt to the environment. Proline accumulation is a key rapid response of chili seedlings to low-temperature osmotic stress and oxidative stress. In the later stages, proline can be degraded into the tricarboxylic acid cycle, providing nitrogen and energy for recovery growth. Therefore, comparative examples 2 and 3, by increasing the content of soluble protein and proline in chili seedlings, enhanced the osmotic regulation function of the cell membrane, thereby improving its resistance to low-temperature stress. From the perspective of comprehensive physiological indicators, the expression response patterns of hypothermia resistance differed among different treatment methods.

[0038] Experimental Example 3: Morphological Trait Indicators Morphological indicators are external phenotypic indicators of plants, resulting from the combined regulation of external environmental factors and the genetic characteristics of the variety itself. Morphological indicators are important parameters for assessing the growth quality of plant seedlings. Low-temperature stress affects the plant height and stem diameter of pepper plants.

[0039] Before transplanting, select 6 pepper seedlings from each treatment whose other physiological indicators were not measured to measure morphological traits such as plant height and diameter. Plant height is the distance from the base of the chili stem to the growing point; stem diameter is the thickness of the stem above the cotyledons. The measurement results are as follows: Figure 5 and Figure 6 As shown; Depend on Figure 5 It can be seen that the effect of treatment 1 on the height of chili seedlings was significantly different from that of comparative example 1, increasing by 25.14% compared to comparative example 1; the treatments of comparative example 2 and comparative example 3 were not significantly different from those of comparative example 1, increasing by 8.38% and 5.59% respectively compared to comparative example 1; Figure 6It can be seen that the diameter of each treatment increased compared with Comparative Example 1, but there was no significant difference. The diameter of the pepper seedlings treated in Example 1, Comparative Example 2, and Comparative Example 3 increased by 8.33%, 5.56%, and 2.78% respectively compared with Comparative Example 1. Therefore, the pepper seedlings in each treatment maintained a balance between stress resistance and growth under low temperature conditions, and promoted cell elongation and division while alleviating stress. This indicates that the application of exogenous growth regulators can promote seedling growth and the construction of new tissues while resisting cold.

[0040] In summary, spraying three different exogenous growth regulators improved the low-temperature resistance of chili seedlings during winter by employing different induction mechanisms. Based on comprehensive physiological, biochemical, and plant morphological analysis, the foliar spraying of 15 mg / L aminoethyl ester in Example 1 was superior to other treatments, promoting robust seedling growth, mitigating the damage of low temperatures to seedlings, and effectively improving the low-temperature tolerance of chili seedlings.

[0041] As can be seen from the above embodiments, the present invention provides a method for overwintering seedling cultivation to improve the low-temperature resistance of chili peppers; this method adopts a segmented seedling cultivation method combining plug trays and nutrient pots to promote the development of chili pepper seedlings, adjust plant metabolism, and enhance adaptability to adverse environments; this method does not require physical heating measures such as electric heating wires and heating furnaces, saving energy, improving the low-temperature resistance of chili pepper seedlings, and promoting seedling growth and development.

[0042] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for overwintering seedling cultivation to improve the low-temperature tolerance of chili peppers, characterized in that, Includes the following steps: (1) Build a three-layer shed, cover it with film, and dig seedbeds inside the shed; (2) After sowing the chili seeds into the seedling trays, cover them with film and place the seedling trays on the seedbed for seedling cultivation; after the chili seedlings emerge, remove the film and continue seedling cultivation; (3) When the peppers have grown to 2 true leaves, transplant them into nutrient pots and place the nutrient pots on the seedbed for seedling cultivation; (4) During the seedling cultivation process, spray amino acid ester when the temperature inside the innermost layer of the greenhouse reaches 8~10℃.

2. The overwintering seedling raising method according to claim 1, characterized in that, The three-tiered greenhouse structure includes a large greenhouse, a medium greenhouse, and a small arched greenhouse. The greenhouse is 8-10m wide and 40-50m long; The width of the central shed is 6-8m and the length is 25-35m; The shed is 1.2-1.4m wide and 10-15m long.

3. The overwintering seedling raising method according to claim 1, characterized in that, The seedbed is 1.2-1.4m wide, 10-15m long, and 5-10cm deep; The seedbed needs to be covered with black non-woven fabric.

4. The overwintering seedling raising method according to claim 1, characterized in that, In step (2), the chili seeds need to be soaked and germinated before sowing; The soaking temperature is 55~60℃; the soaking time is 5~7 hours. The germination temperature is 26~30℃; the germination time is 40~56h.

5. The overwintering seedling raising method according to claim 1, characterized in that, In step (2), the seeding depth is 0.5~1cm.

6. The overwintering seedling raising method according to claim 1, characterized in that, In step (3), the nutrient pot contains mixed soil; the mixed soil includes the following mass percentages of soil: 55-65% fine field soil, 25-35% nutrient soil, and 5-15% bio-organic fertilizer.

7. The overwintering seedling raising method according to claim 1, characterized in that, In step (3), carbendazim needs to be added to the nutrient pot; the amount of carbendazim added is... .

8. The overwintering seedling raising method according to claim 1, characterized in that, In step (4), the concentration of the amino ester is 12~18 mg / L.

9. The overwintering seedling raising method according to claim 2, characterized in that, During the seedling cultivation process, the daytime temperature of the small arched shed is 20~26℃ and the nighttime temperature is 15~18℃; during the seedling division cultivation process, the daytime temperature of the small arched shed is 18~25℃ and the nighttime temperature is 8~14℃.

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