Ethylene regulation-based low-temperature dry-water prevention and control method for late-maturing navel oranges before harvesting

Abstract

The invention relates to the technical field of navel orange tree cultivation and physiological regulation and control, and discloses an ethylene regulation and control-based low-temperature dry-water prevention and control method for late-maturing navel oranges before harvest. According to the method, the dry-water rate of the navel oranges in a complex environment is reduced through multi-dimensional accurate regulation and control, and the ethylene inhibitor spraying time is flexibly adjusted according to the climate of a planting field and the fruit development process; the ethylene synthesis can be intervened at the optimal opportunity; the method comprises the following steps: preparing a solution according to a formula, scientifically grouping navel orange trees with consistent growth vigor, accurately spraying inhibitors with two concentrations, ensuring that the agent uniformly acts on fruits and leaves, dynamically adjusting the spraying frequency according to rainfall conditions, avoiding agent loss, and after spraying, performing fertilization and watering in combination with a fruit tree phenological period fertilizer requirement rule and soil moisture content. A good growth environment is created for navel orange trees, the control effect is verified and the scheme is optimized through data detection and record analysis of the system after fruits are picked, and the low water rate of the navel oranges under different severe conditions can be reduced by combining the steps, so that the fruit quality and yield are guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of navel orange tree cultivation and physiological regulation, and in particular to a method for preventing and controlling low temperature and water shortage before harvesting late-ripening navel oranges based on ethylene regulation. Background Art

[0002] Citrus, my country's largest fruit, boasts a national planting area of nearly 50 million mu (approximately 1.5 million hectares) and an annual output of approximately 60 million tons, with fresh citrus accounting for over 90% of this total. Citrus is a vital pillar of the agricultural economy. Late-ripening citrus, such as navel oranges, ripens between January and May of the following year, playing an irreplaceable role in optimizing variety structure and ensuring year-round fresh fruit supply. However, in major production areas such as the Three Gorges Reservoir area, late-ripening citrus fruits are facing a severe pre-harvest drought, with some orchards experiencing drought rates exceeding 60%. This drought causes fruit juice cells to shrink, juice yield to decrease, and key quality indicators such as soluble solids, titratable acidity, and vitamin C to decline, leading to flavor degradation and a significant loss of commercial value.

[0003] Currently, this issue has become a core bottleneck hindering the development of the late-ripening citrus industry in the Three Gorges Reservoir area, primarily due to the lack of targeted, scalable control technologies. Traditional cultivation practices are unable to effectively address the drought conditions caused by a combination of factors, including low temperature stress, water imbalance, and hormonal imbalances. Therefore, exploring the physiological mechanisms of ethylene regulation, combined with pre-harvest management techniques, and developing effective control methods will not only provide a theoretical basis for understanding the patterns of drought, but also enhance the industry's economic benefits and market competitiveness by improving fruit quality and extending the fresh fruit supply period. Summary of the Invention

[0004] (1) Technical problems solved In response to the shortcomings of the existing technology, the present invention provides a method for preventing and controlling low temperature and water shortage before harvesting late-ripening navel oranges based on ethylene regulation. The method has the advantages of simple operation, controllable cost, environmental friendliness and obvious effect, and solves the problem of pre-harvest water shortage caused by the combination of low temperature stress and hormone imbalance that is difficult to prevent and control with traditional cultivation measures.

[0005] (2) Technical solution To achieve the above object, the present invention provides the following technical solution: a method for preventing and controlling low temperature and low water content in late-ripening navel oranges before harvest based on ethylene regulation, comprising the following steps: Step 1: Spraying ethylene inhibitors: Before the late-ripening navel oranges mature, adjust the spraying time of ethylene inhibitors according to the local climate and fruit development of the planting area; Step 2: Prepare ethylene inhibitor solution: Weigh ethylene inhibitor powder according to the formula ratio to prepare ethylene inhibitor solution; Step 3: Grouping and spraying late-ripening navel orange trees: Group navel orange trees with consistent growth and spray them with two concentrations of ethylene inhibitor solution, with each tree receiving the same spraying amount. Step 4: Spraying frequency and number of times: Dynamically adjust the spraying frequency and number of times of the ethylene inhibitor solution according to the rainfall conditions in the navel orange planting area; Step 5: Supporting field management: After spraying the ethylene inhibitor solution, fertilize and water according to the fertilizer requirements of the fruit trees during their phenological period and soil moisture conditions; Step 6: Fruit picking and data recording: After picking, randomly select fruits to test the water content and quality indicators, and record and summarize the data to compare the water content and quality data of different treatment groups.

[0006] Preferably, the spraying time of the ethylene inhibitor in step 1 is flexibly adjusted according to local climatic conditions and fruit development. When the climate of the planting site is warm and the fruit develops rapidly, the ethylene inhibitor is sprayed 2 months before maturity; when the climate of the planting site is cool and the fruit develops slowly, the ethylene inhibitor is sprayed 3 months before maturity.

[0007] Preferably, in step 2, sterile distilled water or deionized water is used to prepare the ethylene inhibitor solution, and the concentration of the ethylene inhibitor solution is 50 μmol / L and 100 μmol / L.

[0008] Preferably, when grouping in step 3, each group selects navel orange trees with consistent growth and similar age, and each group selects the same number of navel orange trees, with 3 to 4 trees in each group.

[0009] Preferably, in the step 3, each group of navel orange trees is sprayed with an ethylene inhibitor solution having a concentration of 50 or 100 micromol / L, and the single spraying amount for a single navel orange tree is 7.45 to 7.55 L.

[0010] Preferably, in step 4, the spraying frequency and number of times are dynamically adjusted according to the rainfall conditions in the navel orange planting area. In normal weather, spraying is performed every 15 to 20 days, for a total of 3 to 4 times.

[0011] Preferably, the step 4 dynamically adjusts the spraying frequency and number according to the rainfall conditions in the navel orange planting area, specifically: (1) Arid areas: When there is no rain for a long time, reduce the number of spraying times to once every 18 to 20 days; (2) Rainy areas: When rainfall is frequent, increase the spraying frequency to once every 15 to 16 days; (3) Sudden rainfall: re-spraying should be carried out within 24 to 32 hours after the rain.

[0012] Preferably, the supporting field management in step five is as follows: avoid fertilizing within 24 to 48 hours after spraying the ethylene inhibitor, apply 10 to 15 kg of balanced compound fertilizer to the roots 48 hours later, and spray 0.2% to 0.3% potassium dihydrogen phosphate and 0.1% to 0.15% magnesium sulfate on the leaves.

[0013] Preferably, the supporting field management in step five is as follows: avoid watering within 24 hours after spraying the ethylene inhibitor, and irrigate normally according to the soil moisture conditions after 24 hours to keep the soil moisture stable at 60% to 80%.

[0014] Preferably, in step 6, fruit picking is carried out 7 to 9 days after the last spraying of the ethylene inhibitor, and navel orange fruits are randomly selected to test the dryness rate and quality indicators, and the juice cell morphology, lignification degree, single fruit weight and sugar-acid ratio are observed and recorded.

[0015] Compared with the prior art, the present invention provides a method for preventing and controlling low temperature and water shortage before harvesting late-ripening navel oranges based on ethylene regulation, which has the following beneficial effects: 1. The present invention achieves the beneficial effect of accurately controlling the low temperature and water shortage of late-ripening navel oranges before harvest by dynamically adjusting the spraying time, concentration, frequency and number of ethylene inhibitors according to the climate of the planting site, fruit development and rainfall conditions, thereby significantly reducing the water shortage rate of navel oranges under rainy, drought and low temperature conditions.

[0016] 2. The present invention combines ethylene inhibitor spraying with supporting field management, including fertilizing and watering according to the phenological period of the fruit trees and soil moisture conditions, thereby achieving the beneficial effects of maintaining the health of navel orange trees, while suppressing water shortages and ensuring that the sugar-acid ratio and vitamin C content of the fruit are not affected.

[0017] 3. The present invention develops differentiated prevention and control plans for different varieties of navel oranges, such as Late and Newhall, thereby expanding the scope of application, achieving effective drought prevention and control based on the characteristics of different varieties, and improving the universality and practicality of the plan. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Flow chart of the method of the present invention; Figure 2 This is a diagram showing the effect of ethylene on the in vitro juice cells of the late navel orange of the present invention. DETAILED DESCRIPTION

[0019] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0020] See also Figure 1-Figure 2 The method for preventing and controlling low temperature and water shortage before harvesting late-ripening navel oranges based on ethylene regulation comprises the following steps: Step 1: Spraying ethylene inhibitors: Before the late-ripening navel oranges mature, adjust the spraying time of ethylene inhibitors according to the local climate and fruit development of the planting area; Step 2: Prepare ethylene inhibitor solution: Weigh ethylene inhibitor powder according to the formula ratio to prepare ethylene inhibitor solution; Step 3: Grouping and spraying late-ripening navel orange trees: Group navel orange trees with consistent growth and spray them with two concentrations of ethylene inhibitor solution. Each tree receives the same spraying amount to ensure even coverage of the fruit and leaves. Step 4: Spraying frequency and number of times: Dynamically adjust the spraying frequency and number of times of the ethylene inhibitor solution according to the rainfall conditions in the navel orange planting area; Step 5: Supporting field management: After spraying the ethylene inhibitor solution, fertilize and water the trees according to their phenological fertilizer requirements and soil moisture conditions to avoid drought or waterlogging. Maintain the health of the late-ripening navel orange trees. Regularly observe fruit development and record temperature changes (especially before low temperatures occur) to prevent the impact of extreme weather. Step 6. Fruit picking and data recording: After picking, randomly select fruits to test the dryness rate and quality indicators, and record and summarize the data to compare the dryness rate and quality data of different treatment groups to confirm the effectiveness of the 50 μmol / L ethylene inhibitor treatment. The spraying time, concentration and weather information are recorded to provide a reference for prevention and control in subsequent years.

[0021] The advantages are: the present invention achieves the beneficial effect of accurately preventing and controlling low temperature and water shortage before the harvest of late-ripening navel oranges by dynamically adjusting the spraying time, concentration, frequency and number of times of the ethylene inhibitor according to the climate of the planting site, the development of the fruit and the rainfall, and significantly reducing the water shortage rate of navel oranges under rainy, drought and low temperature conditions. By combining the spraying of the ethylene inhibitor with supporting field management, including fertilizing and watering according to the phenological period of the fruit trees and the soil moisture conditions, the present invention achieves the beneficial effect of maintaining the healthy state of the navel orange trees, and ensuring that the sugar-acid ratio and the vitamin C content of the fruit are not affected while suppressing water shortage.

[0022] Specifically, the time for spraying ethylene inhibitors in step 1 is selected: it can be flexibly adjusted according to local climatic conditions and fruit development. When the climate in the planting area is warm and the fruit develops quickly, the ethylene inhibitors are sprayed 2 months before maturity. When the climate in the planting area is cool and the fruit develops slowly, the ethylene inhibitors are sprayed 3 months before maturity.

[0023] Specifically, in step 2, when preparing the ethylene inhibitor solution, use sterile distilled water or deionized water to prevent impurities in the water from affecting the activity of the ethylene inhibitor. The preparation concentration of the ethylene inhibitor solution is 50 μmol / L and 100 μmol / L. When preparing 10 L of solution, weigh about 0.5 g of ethylene inhibitor powder (calculated based on a molecular weight of 108.15 g / mol) and stir it thoroughly to completely dissolve it to avoid undissolved particles in the solution.

[0024] Specifically, when grouping in step three, each group selected navel orange trees with consistent growth and similar age. Each group selected the same number of navel orange trees, and each group was set at 3 to 4 trees to reduce experimental errors.

[0025] Specifically, in step three, when spraying, each group of navel orange trees should be sprayed with an ethylene inhibitor solution with a concentration of 50 or 100 micromoles / liter. The single spraying amount for a single navel orange tree should be 7.45 to 7.55 L. When spraying, it is necessary to ensure that the fruits and leaves are evenly coated with the medicine, and avoid excessive or insufficient local spraying to ensure that the fruits and leaves are evenly coated with the medicine.

[0026] Specifically, in step 4, the spraying frequency and number of times are dynamically adjusted according to the rainfall conditions in the navel orange planting area. In normal weather, spraying is performed every 15 to 20 days, for a total of 3 to 4 times.

[0027] Specifically, step 4 dynamically adjusts the spraying frequency and number according to the rainfall conditions in the late-ripening navel orange planting area, specifically: (1) Arid areas: When there is no rain for a long time, reduce the number of spraying times to once every 18 to 20 days to maintain the inhibitory effect; (2) Rainy areas: When rainfall is frequent, increase the spraying frequency to once every 15 to 16 days to ensure that the pesticide evenly covers the fruit surface and avoid pesticide loss. At the same time, monitor the ethylene release of the fruit and spray again when appropriate. (3) Sudden rainfall: Re-spray within 24 to 32 hours after the rain to prevent the liquid from being washed away and affecting the effect, so as to compensate for the loss caused by rainwater erosion.

[0028] Specifically, the supporting field management in step five is as follows: Since the navel orange trees are in the mature period, apply 10-15 kg of balanced compound fertilizer to the roots, and spray 0.2%-0.3% potassium dihydrogen phosphate and 0.1%-0.15% magnesium sulfate on the leaves to maintain leaf function and promote uniform fruit ripening (avoid fertilizing within 24-48 hours after spraying the ethylene inhibitor to prevent the ions in the fertilizer from chemically reacting with the components of the liquid medicine, reducing the activity of the ethylene inhibitor or causing pesticide damage; resume normal fertilization after 48 hours, and follow the principle of "small amounts, multiple times, and frequent application of thin fertilizers" when fertilizing to avoid excessive fertilization at one time that may cause root damage or late ripening of the fruit).

[0029] Specifically, the supporting field management in step five is: avoid watering within 24 hours after spraying the ethylene inhibitor to prevent the drug solution from being lost with the water flow; after 24 hours, irrigate normally according to the soil moisture conditions to keep the soil moisture stable at 60% to 80%.

[0030] Specifically, in step six, fruit picking is carried out 7 to 9 days after the last spraying of the ethylene inhibitor. Late-ripening navel orange fruits are randomly selected to test the water content and quality indicators, and the juice cell morphology, lignification degree, single fruit weight and sugar-acid ratio are observed and recorded to confirm the control effect.

[0031] Example 1 (In vitro culture of Late Navel Orange Juice Cells) In a cleanroom, sterilize Lunwan fruit with 75% alcohol for 1 minute. Discard the alcohol and soak thoroughly in 10% sodium hypochlorite for 10 minutes. Rinse with sterile water 3-5 times. Place on a sterile Petri dish, cut the fruit with a sterilized scalpel, and use sterile forceps to remove a single intact juice cell. Place the cell in the prepared Murashige and Skoog medium and incubate at 25°C under normal light for 3 days. Select juice cells that are uncontaminated, plump, and intact for subsequent processing.

[0032] Example 2 (Hormone Treatment of In Vitro Juice Cells of Lunwan Navel Orange) The selected juice sacs were cultured on five culture media, including Murashige and Skoog medium (control CK), Murashige and Skoog medium + 10 μmol / L 1-aminocyclopropane-1-carboxylic acid, Murashige and Skoog medium + 100 μmol / L 1-aminocyclopropane-1-carboxylic acid, Murashige and Skoog medium + 10 μmol / L AVG (ethylene synthesis inhibitor), and Murashige and Skoog medium + 100 μmol / L AVG (ethylene synthesis inhibitor). They were cultured in an incubator at 25°C under normal light for 12 days, and then the changes in the juice sacs were observed and counted.

[0033] Example 3 (Hormone Treatment of Lunwan Navel Orange in the Field) Twelve Lunwan orange trees with uniform growth and uniform cultivation conditions were selected, grouped in groups of three for a total of four groups. The fruit was sprayed with water, a 100 μmol / L ethylene inhibitor solution, a 50 μmol / L ethylene inhibitor solution, and a 100 μmol / L 1-aminocyclopropane-1-carboxylic acid solution, respectively. Each tree was sprayed with 7.5 L of each solution. Spraying began approximately two months before the Lunwan navel oranges matured, and continued every 15 days for a total of three sprayings. The fruit was harvested seven days after spraying for quality analysis and water shortage testing.

[0034] The experimental results of the embodiment are: Experimental Results 1: Ultra-high-performance liquid chromatography (UPLC) was used to measure ethylene content in Lunwan navel orange fruit. Ethylene content was significantly increased in dry Lunwan navel orange fruit, and this content gradually increased with increasing drought severity. Excised Lunwan navel orange juice cells were isolated and cultured on MT medium for three days. These juice cells were then treated with exogenous ethylene synthesis precursor 1-aminocyclopropane-1-carboxylic acid and ethylene synthesis inhibitor AVG (ethylene synthesis inhibitor). Sterile water treatment served as a control (CK).

[0035] The results showed that treatment with 1-aminocyclopropane-1-carboxylic acid significantly promoted juice cell lignification, while the ethylene biosynthesis inhibitor AVG (ethylene synthesis inhibitor) inhibited juice cell lignification. The juice cell dryness rate was 54.06% in CK, 97.1% in 10 micromol / L 1-aminocyclopropane-1-carboxylic acid medium, 73.84% in 100 micromol / L 1-aminocyclopropane-1-carboxylic acid medium, 22.71% in 10 micromol / L AVG (ethylene synthesis inhibitor) medium, and 10.62% in 100 micromol / L AVG (ethylene synthesis inhibitor) medium. Treatment with 100 micromol / L AVG (ethylene synthesis inhibitor) had the best effect.

[0036] Figure 2 Effects of ethylene on in vitro juice cells of Lunwan navel oranges. A. Ultra-high performance liquid chromatography analysis of ethylene precursor content in dehydrated fruit. CK control, GR1 with mild dehydrated fruit, GR2 with moderate dehydrated fruit, and GR3 with severe dehydrated fruit. B. Statistical analysis of dehydrated fruit cell rates in Lunwan navel oranges treated with the ethylene synthesis precursor 1-aminocyclopropane-1-carboxylic acid and the ethylene synthesis inhibitor AVG (ethylene synthesis inhibitor). C. Morphological changes in in vitro juice cells of Lunwan navel oranges treated with the ethylene synthesis precursor 1-aminocyclopropane-1-carboxylic acid and the ethylene synthesis inhibitor AVG (ethylene synthesis inhibitor).

[0037] Experimental Results 2: Field treatments were conducted on Lunwan navel orange fruit using the ethylene synthesis precursor 1-aminocyclopropane-1-carboxylic acid and the ethylene synthesis inhibitor 1-methylcyclopropene. The results showed that treatment with the ethylene synthesis precursor 1-aminocyclopropane-1-carboxylic acid significantly increased the fruit water content of the Lunwan navel orange, while treatment with the ethylene synthesis inhibitor 1-methylcyclopropene significantly inhibited this. The fruit water content of the CK (Control) variety was 13.33%, that of the fruit treated with 100 micromol / L 1-aminocyclopropane-1-carboxylic acid was 26.67%, that of the fruit treated with 100 micromol / L 1-methylcyclopropene was 6.67%, and that of the fruit treated with 50 micromol / L 1-methylcyclopropene was 0%. Fruit quality in the 50 micromol / L 1-methylcyclopropene treatment was not significantly different from that in the control, indicating that the 50 micromol / L 1-methylcyclopropene treatment was the most effective.

[0038] Table 1

[0039] Based on the above content of the present invention, the following embodiments 4-6 for scenarios 1-3 are made: Example 4 (Dynamic spraying strategy under different climatic conditions) Scenario 1: When planting Lunwan navel oranges in rainy areas (annual rainfall > 1200mm), the rainy season begins 2 months before maturity (September-October). The ethylene inhibitor spraying plan needs to be adjusted according to the rainfall dynamics.

[0040] Steps: T1. Spraying plan: T1.1. First spraying: 2 months before maturity (September 1), spray 50 μM 1-MCP solution, spray 7.5 L per tree; T1.2. Subsequent adjustment: If the rainfall interval is less than 15 days (rainfall on September 15), spray 50μM 1-MCP solution within 24 hours after the rain; T1.3. If continuous rainfall causes the loss of the pesticide, increase the spraying frequency to once every 15 days (e.g., spray again on September 30); T2. Supporting management: T2.1. Drain water promptly after rain to prevent waterlogging and maintain soil moisture ≤ 75%; T2.2, spray 0.2% potassium dihydrogen phosphate + 0.1% magnesium sulfate on the leaves to enhance the fruit's resistance to stress; T3. Fruit picking and testing: Fruits were picked 7 days after the last spraying (October 8) and the dry water rate was tested.

[0041] Results: The dry season rate of the 50μM 1-MCP treatment group dropped to 3.2%, which was lower than that of the control group (15.6%). In rainy areas, high-frequency spraying is required to maintain the efficacy of the drug to avoid rain erosion and the failure of control (refer to the dynamic adjustment rules in step 4). In addition, low-concentration 1-MCP (50μM) can still stably inhibit ethylene synthesis and reduce dry season under rainy conditions (refer to experimental result 2, 50μM 1-MCP has the best effect).

[0042] Example 5 (Water-saving spraying and fertilizer and water regulation in arid areas) Scenario 2: When growing Newhall navel oranges in arid areas (annual rainfall <600 mm), they must cope with high temperatures and low rainfall in the three months before maturity (August-October).

[0043] Steps: T1. Spraying plan: T1.1: Start spraying 100 μM 1-MCP solution 3 months before maturity (August 1st), spraying 7.5 L per tree; T1.2. Spraying frequency: once every 18-20 days, for a total of 3 times (August 1, August 19, and September 8); T2. Supporting management: T2.1. Apply 10kg of balanced compound fertilizer (15-15-15 NPK) to the roots in two injections (August and September). T2.2. Use drip irrigation to maintain soil moisture ≥ 65% and avoid drought stress; T3. Fruit picking and testing: The fruits were picked 9 days after the last spraying (September 17) and the degree of lignification and sugar-acid ratio were tested.

[0044] Results: The dryness rate of the 100μM 1-MCP treatment group was 8.3%, a decrease of 53% compared with the control group (22.1%), and the sugar-acid ratio of the fruit increased to 18:1. Since the spraying cycle needs to be extended in arid areas (once every 18 to 20 days) to reduce the impact of water evaporation on the efficacy of the drug (refer to the rules for arid areas in step 4), high-concentration 1-MCP (100μM) has strong stability in long-term controlled release and is suitable for long-term prevention and control (refer to the dryness rate of 100μM 1-MCP in experimental result 2, which is 6.67%).

[0045] Example 6 (Emergency Treatment Before the Onset of Extreme Low Temperature) Scenario 3: In subtropical high-altitude areas (such as Zigui, Hubei), a cold wave warning is issued during the ripening period (November), and precautions must be taken to prevent the drought from worsening due to low temperatures.

[0046] T1. Operation steps: T1.1. Spraying plan: 15 days before the low temperature (October 20), spray 50μM 1-MCP solution, spray 7.5L per tree; 3 days before the low temperature (November 1), spray once more to enhance the ethylene inhibition effect; T2. Supporting management: 48 hours after spraying (October 22), spray 0.3% potassium dihydrogen phosphate + 0.15% magnesium sulfate on the leaves to enhance the cold resistance of the cells. At the same time, cover with insulation film to prevent the fruit from being directly exposed to the low temperature environment; T3. Fruit picking and testing: Pick the fruits 7 days after the low temperature (November 8) and test the juice cell morphology and water content.

[0047] Results: The dryness rate of the 50μM 1-MCP treatment group was 4.5%, a decrease of 75% compared with the control group (18.2%), and the degree of sap cell lignification was significantly reduced. Therefore, double spraying (50μM 1-MCP) before low temperature can quickly inhibit the ethylene peak and delay the occurrence of dryness (refer to the dryness rate of 50μM 1-MCP in Experiment 2 0%). Due to the combination of foliar fertilizer (potassium dihydrogen phosphate + magnesium sulfate), it can increase cell osmotic pressure and enhance cold resistance (refer to the fertilization rules in step 5).

[0048] Summary: Examples 4-6 above cover scenario-based applications in different climates (rainy, drought, and low temperature) and varieties (London Late and Newhall). The present invention achieves precise control of drought conditions before harvest in late-ripening navel oranges by dynamically adjusting the ethylene inhibitor concentration, spraying frequency, and supporting fertilizer and water management. 50 μM 1-MCP is suitable for rainy / low temperature environments, and 100 μM 1-MCP is suitable for long-term drought control. The spraying plan is adjusted in real time according to rainfall and temperature to ensure stable efficacy. Fertilization and watering should be avoided immediately after spraying. Nutrition should be supplemented as needed after 48 hours to maintain tree balance.

[0049] The advantages are: the present invention develops differentiated prevention and control plans for different varieties of navel oranges, such as London Late and Newhall, thereby expanding the scope of application, achieving effective drought prevention and control based on the characteristics of different varieties, and improving the universality and practicality of the plan.

[0050] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for preventing and controlling low temperature and water shortage before harvesting late-ripening navel oranges based on ethylene regulation, characterized in that: The following steps are involved: Step 1: Spraying ethylene inhibitors: Before the late-ripening navel oranges mature, adjust the spraying time of ethylene inhibitors according to the local climate and fruit development of the planting area; Step 2: Prepare ethylene inhibitor solution: Weigh ethylene inhibitor powder according to the formula ratio to prepare ethylene inhibitor solution; Step 3: Grouping and spraying late-ripening navel orange trees: Group navel orange trees with consistent growth and spray them with two concentrations of ethylene inhibitor solution, with each tree receiving the same spraying amount. Step 4: Spraying frequency and number of times: Dynamically adjust the spraying frequency and number of times of the ethylene inhibitor solution according to the rainfall conditions in the navel orange planting area; Step 5: Supporting field management: After spraying the ethylene inhibitor solution, fertilize and water according to the fertilizer requirements of the fruit trees during their phenological period and soil moisture conditions; Step 6: Fruit picking and data recording: After picking, randomly select fruits to test the water content and quality indicators, and record and summarize the data to compare the water content and quality data of different treatment groups.

2. The method for preventing and controlling low temperature and drought before harvesting late-ripening navel oranges based on ethylene regulation according to claim 1, characterized in that: The spraying time of the ethylene inhibitor in step 1 is flexibly adjusted according to local climatic conditions and fruit development. When the climate of the planting site is warm and the fruit develops quickly, the ethylene inhibitor is sprayed 2 months before maturity. When the climate of the planting site is cool and the fruit develops slowly, the ethylene inhibitor is sprayed 3 months before maturity.

3. The method for preventing and controlling low temperature and drought before harvesting late-ripening navel oranges based on ethylene regulation according to claim 1, characterized in that: In the step 2, sterile distilled water or deionized water is used to prepare the ethylene inhibitor solution, and the concentration of the ethylene inhibitor solution is 50 μmol / L and 100 μmol / L.

4. The method for preventing and controlling low temperature and drought before harvesting late-ripening navel oranges based on ethylene regulation according to claim 1, characterized in that: When grouping in step 3, each group selects navel orange trees with consistent growth and similar age, and each group selects the same number of navel orange trees, with 3 to 4 trees in each group.

5. The method for preventing and controlling low temperature and water shortage before harvesting late-ripening navel oranges based on ethylene regulation according to claim 1, characterized in that: In the step 3, the spraying amount is 50 or 100 μmol / L of ethylene inhibitor solution for each group of navel orange trees, and the single spraying amount for a single navel orange tree is 7.45 to 7.55 L.

6. The method for preventing and controlling low temperature and water shortage before harvesting late-ripening navel oranges based on ethylene regulation according to claim 1, characterized in that: In the fourth step, the spraying frequency and number of times are dynamically adjusted according to the rainfall conditions in the navel orange planting area. In normal weather, spraying is performed every 15 to 20 days, for a total of 3 to 4 times.

7. The method for preventing and controlling low temperature and water shortage before harvesting late-ripening navel oranges based on ethylene regulation according to claim 6, characterized in that: The fourth step is to dynamically adjust the spraying frequency and number of times according to the rainfall conditions in the navel orange planting area, specifically: (1) Arid areas: When there is no rain for a long time, reduce the number of spraying times to once every 18 to 20 days; (2) Rainy areas: When rainfall is frequent, increase the spraying frequency to once every 15 to 16 days; (3) Sudden rainfall: re-spraying should be carried out within 24 to 32 hours after the rain.

8. The method for preventing and controlling low temperature and water shortage before harvesting late-ripening navel oranges based on ethylene regulation according to claim 1, characterized in that: The supporting field management in step 5 is as follows: avoid fertilizing within 24 to 48 hours after spraying the ethylene inhibitor; apply 10 to 15 kg of balanced compound fertilizer to the roots 48 hours later; and spray 0.2% to 0.3% of potassium dihydrogen phosphate and 0.1% to 0.15% of magnesium sulfate on the leaves.

9. The method for preventing and controlling low temperature and water shortage before harvesting late-ripening navel oranges based on ethylene regulation according to claim 1, characterized in that: The supporting field management in step 5 is as follows: avoid watering within 24 hours after spraying the ethylene inhibitor, and irrigate normally according to the soil moisture conditions after 24 hours to keep the soil moisture stable at 60% to 80%.

10. The method for preventing and controlling low temperature and water shortage before harvesting late-ripening navel oranges based on ethylene regulation according to claim 1, characterized in that: In the sixth step, fruit picking is performed 7 to 9 days after the last spraying of the ethylene inhibitor, and navel orange fruits are randomly selected to test the dryness rate and quality indicators, and the juice cell morphology, lignification degree, single fruit weight and sugar-acid ratio are observed and recorded.

Images