A method and cold-resistant agent for improving the cold resistance of peach trees under extreme low temperatures.

Abstract

This invention provides a method and cold-resistant agent for improving the cold resistance of peach trees under extreme low temperatures, belonging to the field of peach tree stress-resistant cultivation technology. By optimizing the application concentration of exogenous salicylic acid (SA) and applying it before peach dormancy, this invention can resist chilling injury caused by extreme low temperatures, reducing the relative conductivity of cell membranes in peach trees by more than 25% and the malondialdehyde content by more than 36%. Simultaneously, it significantly increases the activity of antioxidant enzymes and the accumulation of osmotic regulators, effectively reducing the rate of frost damage to branches. This invention is simple to operate, environmentally friendly, and low in cost, suitable for cold-resistant cultivation of peach trees in northern regions, effectively solving the problem of winter frost damage to peach trees and providing technical support for improving the quality and efficiency of the peach industry.

Description

Technical Field

[0001] This application belongs to the field of peach tree stress-resistant cultivation technology, specifically relating to a method and cold-resistant agent for improving the cold resistance of peach trees under extreme low temperatures. Background Technology

[0002] Northern China, located in the temperate and cold-temperate zones, is significantly influenced by the continental monsoon climate. Winters in this region are characterized by prolonged periods of low temperatures, rapid temperature drops, large diurnal temperature variations, and frequent extreme low temperatures. Furthermore, low precipitation and dry air in winter exacerbate the stress of low temperatures on peach tree growth. Extreme winter temperatures in northern China can reach below -30°C, and these low temperatures can last for 1-3 months. This prolonged extreme cold environment disrupts the physiological balance of peach trees. Frost damage during winter has always been a core bottleneck restricting the high-quality development of the peach industry in northern China. It not only leads to a significant decrease in peach yield and deterioration in fruit quality, but in severe cases, it can cause frost damage, rot, and even death of the entire tree, resulting in huge economic losses for fruit farmers and limiting the large-scale and standardized development of peach cultivation in northern China.

[0003] Conventional physical protection methods are unsuitable for peach trees overwintering due to the difficulty in predicting and responding in advance. Spraying chemical cold-resistant agents can lead to problems such as pesticide residues and environmental pollution, and their short-term effects make long-term effective cold protection difficult. Furthermore, they lack specificity, failing to provide customized solutions based on the cold-resistance needs of different peach varieties, resulting in inconsistent cold-resistance effects. Salicylic acid (SA) is an environmentally friendly endogenous plant signaling molecule that can enhance cold resistance by activating the plant's antioxidant defense system, regulating the accumulation of osmotic substances, and modulating hormone signaling networks. Therefore, salicylic acid is often used in combination with other cold-resistant agents, but its cold-resistance range is limited to 0–15°C, and its effectiveness in extreme low-temperature conditions (-30–-20°C) has not been reported. Summary of the Invention

[0004] The purpose of this invention is to provide a cold-resistant agent for peach trees suitable for extreme low-temperature conditions. By optimizing the working concentration of exogenous salicylic acid, the resistance of peach trees to extreme low temperatures can be effectively improved.

[0005] This invention provides a cold-resistant agent for peach trees, the active ingredient of which is exogenous salicylic acid; the application concentration of the exogenous salicylic acid is 55~65 mg / L.

[0006] Preferably, the concentration of the exogenous salicylic acid is 60 mg / L.

[0007] Preferably, it also includes an adhesive or a surfactant.

[0008] This invention provides the application of the peach tree cold-resistant agent in the cold resistance of peach trees under extreme low temperatures, including -30 to -6°C.

[0009] Preferably, the extreme low temperature includes -24 to -12°C.

[0010] Preferably, the extreme low temperature includes -22 to -18°C.

[0011] This invention provides a method for improving the cold resistance of peach trees under extreme low temperatures, comprising the following steps: Apply the aforementioned peach tree anti-cold agent before the peach trees go dormant.

[0012] Preferably, the method of applying the peach tree cold-resistant agent includes spraying; The spraying is performed 2 to 3 times, with an interval of 7 to 15 days between two consecutive sprayings.

[0013] This invention provides a peach tree cold-resistant agent, which has the following beneficial effects: Significant cold resistance: This invention uses exogenous salicylic acid as the sole active ingredient and specifies the application concentration of exogenous salicylic acid, which enables peach trees to maintain high cell membrane stability, antioxidant capacity and water retention capacity even at extreme low temperatures (-30℃), and significantly reduces the frost damage rate of branches; Environmentally friendly and safe: SA is an endogenous signaling substance in plants. It is used in low amounts and leaves no residue, so it will not pollute the environment and meets the needs of green agricultural development. Wide range of applications: Applicable to peach varieties in the north, especially effective for varieties with high economic value. Simple to operate, low cost, and easy to promote and apply on a large scale.

[0014] This invention provides a method for improving the cold resistance of peach trees under extreme low temperatures by applying a peach tree cold-resistant agent during the peach tree's dormancy. By clearly defining the application period of the peach tree cold-resistant agent, this invention avoids the problem of unstable application effects caused by ambiguous parameters in existing technologies. It can be directly applied to field production, is simple to operate, and reduces the need for winter preparation measures for peach tree cultivation in northern my country, thus reducing manpower and material resources. Attached Figure Description

[0015] Figure 1 The effect of different concentrations of SA treatment on the malondialdehyde (MDA) content in the branches of *Prunus cerasifera*. Figure 2 The results show the effect of different concentrations of SA treatment on the SOD activity of Prunus japonica branches; Figure 3 The effect of different concentrations of SA treatment on the endogenous ABA content of Jiuqing peach. Detailed Implementation

[0016] This invention provides a peach tree cold-resistant agent, the active ingredient of which includes exogenous salicylic acid; the concentration of the exogenous salicylic acid is 55~65 mg / L.

[0017] In this invention, the concentration of exogenous salicylic acid is preferably 58-62 mg / L, and can be 60 mg / L. In this embodiment, the exogenous salicylic acid was purchased from Shanghai Yi'en Chemical Technology Co., Ltd. A suitable concentration of exogenous salicylic acid is beneficial for resisting the stress of extreme low temperatures on peach trees. The core technical principle is a cold-resistance regulatory pathway of "SA signaling - hormone network - multi-system synergy": First, exogenous salicylic acid activates hormone network regulation: 60 mg / L SA can significantly induce the accumulation of endogenous abscisic acid (ABA) (more than 4 times higher than the control), constructing an "SA-ABA" synergistic signaling network and initiating downstream cold-resistance responses; second, exogenous salicylic acid activates the antioxidant system: through hormone signaling, superoxide dismutase (SOD) activity is significantly increased, with SOD activity at -30℃ increasing by 91.7% compared to the control, effectively inhibiting membrane lipid peroxidation. In addition, exogenous salicylic acid also plays a role in cell membrane protection: through the above-mentioned multi-system synergistic effect, it reduces electrolyte leakage, and at -30℃, the relative conductivity of branches is reduced by 25.3% compared with the control, and the malondialdehyde content is reduced by 36.4%, which significantly reduces cell membrane damage.

[0018] In this invention, the cold-resistant agent preferably also includes an adhesive or surfactant, which helps to improve the adhesion of the active ingredients in peach trees, increase the drug utilization rate of the active ingredients, and reduce the application amount while achieving the cold-resistant effect, thus lowering planting costs. The adhesive preferably includes natural polymeric adhesives, synthetic polymeric adhesives, and natural adhesives. The natural polymeric adhesives preferably include polysaccharides (starch, cellulose, chitosan, etc.) and proteins (gelatin, casein, etc.). The synthetic polymeric adhesives preferably include polyacrylamide and its derivatives, polyvinyl alcohol, carboxymethyl cellulose, etc. The natural adhesives preferably include mineral oil, animal and vegetable oils, soybean flour, gum, waste molasses, etc. The surfactant preferably includes 0.1% of a nonionic surfactant (such as Tween-80).

[0019] This invention provides the application of the peach tree cold-resistant agent in the cold resistance of peach trees under extreme low temperatures, including -30 to -6°C.

[0020] In this invention, the extreme low temperature preferably includes -24 to -12°C, but can be -22 to -18°C or -20°C. In this embodiment of the invention, the cold resistance effect of the peach tree anti-cold agent on peach trees under extreme low temperatures is illustrated using a peach tree (Jiuqing peach) as an example.

[0021] This invention provides a method for improving the cold resistance of peach trees under extreme low temperatures, comprising the following steps: Apply the aforementioned peach tree anti-cold agent before the peach trees go dormant.

[0022] In this invention, the method of applying the peach tree cold-resistant agent preferably includes spraying. The number of sprayings is preferably 2-3 times, but can be 2 times. The interval between two consecutive sprays is preferably 7-15 days, but can be 10 days. The spraying dosage is based on the amount of water dripping from the leaves. The application of the agent before the peach tree enters dormancy is preferably 10-30 days before leaf fall, but can be 15-20 days before leaf fall.

[0023] In this invention, the cold resistance is manifested in maintaining low cell membrane stability, reducing membrane lipid peroxidation, decreasing antioxidant activity, and increasing endogenous hormone levels. Cell membrane stability is characterized by relative conductivity (REC). Experiments show that the REC of 60 mg / L exogenous salicylic acid at -30°C is approximately 35.5% (approximately 28% lower than the 47.5% in the control group). Membrane lipid peroxidation is characterized by MDA content. The MDA content of 60 mg / L exogenous salicylic acid is significantly lower than that of the control group at -24°C to -30°C, reaching approximately 5.0 μmol / g at -30°C (approximately 35% lower than the 7.7 μmol / g in the control group). The SOD activity of 60 mg / L exogenous salicylic acid reaches its peak at -6°C (approximately 8.5 U / g FW), significantly higher than that of the control group (approximately 4.0 U / g FW), and remains at a high level at -24°C to -30°C. Endogenous hormones were characterized using ABA as an example. ABA accumulation is a key mechanism for enhancing cold resistance. Exogenous salicylic acid at 0 mg / L resulted in an ABA content of approximately 3.3 × 10⁻⁶ in peach trees. 4 pg / 10000g, compared to the CK group (approximately 0.5×10 pg / 10000g). 4 The SA concentration (pg / 10000g) increased by approximately four times, significantly higher than other treatment groups. The results indicated that the 60 mg / L SA treatment had the best effect on improving the cold resistance of Jiuqing peach, while the high concentration of 120 mg / L SA treatment led to hormonal network disruption and a significant decrease in cold resistance. Further field validation showed that after extreme winter temperatures (-28℃), the SA-treated group had a frost damage rate of 12.5% ​​(compared to 38.2% in the control group), a budding rate of 89.6% (compared to 65.3% in the control group), and a fruit set rate of 78.3% (compared to 52.6% in the control group), significantly better than the control group.

[0024] The spraying period described in this invention is 10-30 days (15-20 days) before the peach trees shed their leaves. The specific timing can be adjusted according to local climate differences, starting when the local minimum temperature is 0-2℃. Adhesives or nonionic surfactants can be added to the SA solution to improve adhesion, but small-scale trials must be conducted beforehand to ensure no phytotoxicity. This invention activates the peach tree's own cold-resistance mechanism through precise concentration and timing control, rather than relying on direct protection from exogenous chemical agents, resulting in a long-lasting and stable cold-resistance effect.

[0025] The following detailed description, in conjunction with embodiments, illustrates a method and cold-resistant agent for improving the cold resistance of peach trees under extreme low temperatures provided by the present invention. However, these descriptions should not be construed as limiting the scope of protection of the present invention.

[0026] Example 1 Effects of different concentrations of SA on the cold resistance of Jiuqing peach 1. Experimental materials: Eighteen Jiuqing peach trees of uniform age, moderate growth vigor, and free from pests and diseases were selected from the peach germplasm resource nursery of a base of Hebei University of Science and Technology. They were divided into 6 groups, with 3 trees in each group and 1 tree between groups.

[0027] 2. Experimental treatment: On the afternoon of October 28, 2024 (sunny and windless), six groups of plants were sprayed with different concentrations of SA solution: CK (0 mg / L, water), T1 (5 mg / L), T2 (15 mg / L), T3 (30 mg / L), T4 (60 mg / L), and T5 (120 mg / L). The amount of spraying was such that the leaves dripped water.

[0028] 3. Low temperature treatment: After spraying, wait for the peach trees to enter dormancy, collect one-year-old branches (0.3~0.6cm in diameter) from the outer canopy of each group, and subject them to gradient low temperature treatments of 4℃, -6℃, -12℃, -18℃, -24℃ and -30℃ respectively. Each temperature is maintained for 12 hours. After treatment, the branches are restored in a 4℃ refrigerator for 9 hours, and physiological indicators are measured.

[0029] 4. Measurement indicators: relative conductivity (REC), malondialdehyde (MDA) content, antioxidant enzyme (SOD) activity, and endogenous hormone (ABA) content.

[0030] The results above indicate that (1) cell membrane stability (relative conductivity): the T4 group maintained the lowest relative conductivity under each temperature gradient, with REC of approximately 35.5% at -30℃ (approximately 28% lower than the 47.5% of the CK group); the T5 group (120 mg / L) had the highest conductivity, indicating that high concentrations of SA exacerbated cell membrane damage (Table 1).

[0031] Table 1. Effects of different SA concentrations on the relative conductivity of *Prunus japonica* branches.

[0032] (2) Degree of membrane lipid peroxidation (MDA content): The MDA content of group T4 was significantly lower than that of group CK at -24℃ to -30℃, and the MDA content at -30℃ was about 5.0 μmol / g (about 35% lower than that of group CK, which was 7.7 μmol / g); group T5 had the highest MDA content and the most severe membrane lipid peroxidation. Figure 1 ).

[0033] (3) Antioxidant enzyme activity (SOD): The SOD activity in the T4 group reached its peak at -6℃ (approximately 8.5 U / g FW), which was significantly higher than that in the CK group (approximately 4.0 U / g FW); it also maintained a high level at -24℃ to -30℃. Figure 2 ).

[0034] (4) Endogenous hormones (ABA content): The ABA content in group T4 was approximately 3.3 × 10⁻⁶. 4 pg / 10000g, compared to the CK group (approximately 0.5×10 pg / 10000g). 4 The concentration of ABA increased by approximately 4 times, significantly higher than other treatment groups, indicating that SA-induced ABA accumulation is a key mechanism for enhancing cold resistance. Figure 3 ).

[0035] The above results indicate that 60 mg / L SA treatment has the best effect on improving the cold resistance of Jiuqing peach, while 120 mg / L SA treatment leads to hormone network disorder and significantly reduces the cold resistance effect.

[0036] Example 2 Field application effect verification of optimal concentration of SA 1. Experimental Design: Sixty Jiuqing peach trees from a peach orchard in a county of Qinhuangdao City, Hebei Province, were randomly divided into two groups of 30 trees each, with isolation rows between the groups. The experimental group was sprayed with a 60 mg / L SA solution, with the amount sprayed just enough to wet the branches and trunk. The control group was sprayed with water. The spraying time and method were the same as in Example 1.

[0037] 2. Field management: Both groups of plants were managed using the same field management measures, including fertilization, watering, and pest and disease control.

[0038] 3. Effect survey: After the extreme low temperature in winter (-28℃), the frost damage rate of branches, budding rate and fruit setting rate were investigated.

[0039] Results: The frost damage rate of branches in the experimental group was 12.5% ​​(compared to 38.2% in the control group), the budding rate was 89.6% (compared to 65.3% in the control group), and the fruit setting rate was 78.3% (compared to 52.6% in the control group), which were significantly better than those in the control group, confirming that the field application effect of the method of the present invention is stable.

[0040] 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 cold-resistant agent for peach trees, characterized in that, The active ingredient includes exogenous salicylic acid; the concentration of the exogenous salicylic acid is 55~65 mg / L.

2. The peach tree cold-resistant agent according to claim 1, characterized in that, The concentration of the exogenous salicylic acid is 60 mg / L.

3. The peach tree cold-resistant agent according to claim 1 or 2, characterized in that, It also includes adhesives or surfactants.

4. The application of the peach tree cold-resistant agent according to any one of claims 1 to 3 in the cold resistance of peach trees under extreme low temperatures, wherein the extreme low temperatures include -30 to -6°C.

5. The application according to claim 4, characterized in that, The extreme low temperatures range from -24 to -12°C.

6. The application according to claim 4, characterized in that, The extreme low temperatures range from -22 to -18°C.

7. A method for improving the cold resistance of peach trees under extreme low temperatures, characterized in that, Includes the following steps: Before the peach trees go dormant, apply the peach tree cold-resistant agent according to any one of claims 1 to 3.

8. The method according to claim 7, characterized in that, The method of applying the peach tree cold-resistant agent includes spraying.

9. The method according to claim 8, characterized in that, The spraying is performed 2 to 3 times.

10. The method according to claim 9, characterized in that, The interval between two consecutive sprayings should be 7 to 15 days.

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