Method for alleviating high temperature heat damage of rice

Abstract

The application discloses a method for relieving high-temperature heat damage of rice, and relates to the technical field of rice cultivation. The method for relieving high-temperature heat damage of rice is characterized by spraying a first adjusting agent on rice plants when the rice suffers from high-temperature heat damage stress during the heading and flowering period, and spraying a second adjusting agent before the first adjusting agent is applied. The first adjusting agent contains methyl jasmonate with a concentration of 1-4 mmol / L, tannic acid with a concentration of 10-40 mg / L, calcium nitrate with a concentration of 6-20 mg / L and betaine with a concentration of 12-30 mg / L. The second adjusting agent is mainly mixed by propylene glycol and humic acid with a weight ratio of 1:10-20. The application solves the problems of unstable effect and low efficiency of using methyl jasmonate alone to relieve high-temperature heat damage.

Description

Technical Field

[0001] The invention relates to the technical field of rice cultivation, and in particular to a method for alleviating high-temperature heat damage to rice. Background Art

[0002] Rice (Oryza sativa L.) is a thermophilic, short-day crop that has developed a degree of adaptability to high temperatures over its long evolutionary history. However, when ambient temperatures exceed the critical threshold for optimal growth, they can negatively impact normal rice growth. Studies have shown that exposure to temperatures above 35°C during the reproductive phase can harm rice plants, with each 1°C increase in temperature resulting in a 10% yield loss. Frequent heat damage in recent years has severely impacted rice yield and quality.

[0003] Current methods for mitigating heat damage in rice include planting heat-tolerant rice varieties, staggered sowing, and applying plant growth regulators. However, heat-tolerant rice varieties are relatively rare, and different varieties have varying heat tolerance periods. Some varieties are relatively heat-tolerant during the flowering phase, but less so during the grain-filling phase, making it difficult to meet demand. Furthermore, the long breeding cycle and aging time make rapid utilization difficult. Plant growth regulators are the most commonly used method, and numerous studies have reported using them to mitigate heat damage in rice. These include ABA, salicylic acid, 6-BA, 2,4-epibrassinolide, and exogenous KT (CN 105210748B, CN 112385496 B, and CN 116584268 A). In previous studies, the applicant discovered that methyl jasmonate (MeJA) is an important plant signal transduction substance that plays an important role in regulating stress resistance. Spraying a certain concentration of MeJA on rice panicles can significantly alleviate high temperature heat damage and increase the fruit set rate. However, its effect is not significant if used alone or at an inappropriate time. In addition, the effect of plant growth regulators is easily affected by the environment and the effect is unstable. Therefore, it is necessary to improve the use of plant growth regulators to improve their effect.

[0004] In summary, the purpose of the present invention is to provide a method for alleviating high temperature heat damage to rice, so as to effectively alleviate the damage caused by high temperature stress to rice, which has important practical significance for ensuring high and stable yield of rice. Summary of the Invention

[0005] In view of the above shortcomings, the present invention provides a method for alleviating high temperature heat damage to rice, which solves the problem that the effect of using methyl jasmonate alone to alleviate high temperature heat damage is unstable and inefficient. The specific technical solution is as follows:

[0006] A method for alleviating high-temperature heat damage to rice comprises spraying a first regulator on the rice plants when the rice plants are under high-temperature heat stress during the heading and flowering stages, and spraying a second regulator before applying the first regulator;

[0007] The first regulator contains methyl jasmonate at a concentration of 1-4 mmol / L, tannic acid at a concentration of 10-40 mg / L, calcium nitrate at a concentration of 6-20 mg / L, and betaine at a concentration of 12-30 mg / L;

[0008] The second regulator is mainly composed of a mixture of propylene glycol and humic acid in a weight ratio of 1:10-20.

[0009] Furthermore, the high temperature heat stress refers to daytime temperatures exceeding 35°C for more than three consecutive days.

[0010] Furthermore, the first regulator is sprayed continuously for 3-5 days, once a day, with a spraying amount of 40-60 kg / mu each time, and is evenly sprayed on the rice plants during spraying.

[0011] Furthermore, the first conditioning agent further comprises an auxiliary agent, which is an ethanol solution with a mass concentration of 30-40%, and the auxiliary agent accounts for 0.1-0.4% of the total weight of the methyl jasmonate, tannic acid, calcium nitrate and betaine. The ethanol solution serves as a developing agent to better disperse the raw materials in the first conditioning agent.

[0012] Furthermore, the second regulator is sprayed 1-3 hours before the first regulator is applied.

[0013] Furthermore, the second regulator is diluted with water in an amount of 800-1000 times the total weight of propylene glycol and humic acid before spraying.

[0014] Furthermore, the second regulator is sprayed at a rate of 10-20 kg / mu and is evenly sprayed onto the rice plants.

[0015] Furthermore, the method for alleviating high-temperature heat damage to rice also includes irrigating the field during the period when the rice is subjected to high-temperature heat stress to maintain water in the field.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. The present invention sprays the second regulator before applying the first regulator, and the first regulator is tannic acid, calcium nitrate and betaine combined with the plant growth regulator methyl jasmonate, thereby solving the problem that the use of methyl jasmonate alone in alleviating high temperature heat damage is unstable and inefficient.

[0018] 2. Before applying the first regulator of the present invention, the second regulator is sprayed first. The second regulator can enhance the efficiency of the first regulator. Specifically, the propylene glycol in the second regulator can absorb water vapor, increase the humidity of the leaf surface, and improve the adsorption strength and absorption rate of the leaves to the first regulator, so that the first regulator can play a stable role; humic acid can adjust the pH environment on the leaf surface and in the cells, activate the internal defense mechanism of the plant, and create more suitable conditions for the physiological process of the first regulator. Therefore, spraying propylene glycol and humic acid before applying the first regulator can provide better environmental conditions for the first regulator and prevent the first regulator from being unstable due to environmental influences.

[0019] 3. The methyl jasmonate in the first regulator of the present invention can help rice resist high temperature stress. Tannic acid absorbs some light, protecting methyl jasmonate from photolysis and reduced effectiveness during use. Calcium nitrate can be converted into nitric oxide by the plant, participating in heat damage resistance reactions. Betaine stabilizes cell structure and protects enzyme activity. Tannic acid, calcium nitrate, and betaine collectively enhance the effectiveness of methyl jasmonate. Therefore, the combined effects of tannic acid, calcium nitrate, betaine, and methyl jasmonate improve rice's tolerance to high temperatures. DETAILED DESCRIPTION

[0020] The specific embodiments of the present invention are described in detail below, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments.

[0021] The following methyl jasmonate, salicylic acid, tannic acid, betaine, humic acid, calcium nitrate and propylene glycol are all produced by Sigma.

[0022] Example 1

[0023] A method for alleviating high-temperature heat damage to rice comprises spraying a first regulator on the rice plants during the heading and flowering stages when the rice plants are experiencing high-temperature heat stress. A second regulator is sprayed one hour before the first regulator is applied. The first regulator is sprayed once daily for three consecutive days at a rate of 60 kg per mu (approximately 1.5 acre) and evenly applied to the rice plants. The second regulator is applied at a rate of 20 kg per mu (approximately 1.000 times the total weight of propylene glycol and humic acid) before spraying and evenly applied to the rice plants. Simultaneously, irrigation is performed during the period of high-temperature heat stress to maintain a water-rich state.

[0024] The first conditioning agent comprises 4 mmol / L methyl jasmonate, 40 mg / L tannic acid, 20 mg / L calcium nitrate, and 30 mg / L betaine, as well as a 40% ethanol solution, where the ethanol solution accounts for 0.4% of the total weight of the methyl jasmonate, tannic acid, calcium nitrate, and betaine. The ethanol solution serves as a developing agent to better disperse the ingredients in the first conditioning agent. The second conditioning agent is a mixture of propylene glycol and humic acid in a weight ratio of 1:20.

[0025] Example 2

[0026] A method for alleviating heat damage to rice comprises spraying a first regulator on the rice plants during the heading and flowering stages when the rice plants are exposed to heat stress. A second regulator is sprayed 3 hours prior to the first regulator. The first regulator is sprayed daily for 5 consecutive days at a rate of 40 kg per mu (approximately 1.5 acre) and evenly applied to the rice plants. The second regulator is applied at a rate of 10 kg per mu (approximately 1.5 acre) and diluted with water (800 times the total weight of propylene glycol and humic acid) before spraying. The second regulator is evenly applied to the rice plants. Simultaneously, irrigation is performed during the heat stress period to maintain the rice plants hydrated.

[0027] The first conditioning agent comprises 1 mmol / L methyl jasmonate, 10 mg / L tannic acid, 6 mg / L calcium nitrate, and 12 mg / L betaine, as well as a 30% ethanol solution, where the ethanol solution accounts for 0.1% of the total weight of the methyl jasmonate, tannic acid, calcium nitrate, and betaine. The ethanol solution serves as a developing agent to better disperse the ingredients in the first conditioning agent. The second conditioning agent is a mixture of propylene glycol and humic acid in a weight ratio of 1:10.

[0028] Example 3

[0029] A method for alleviating high-temperature heat damage to rice comprises spraying a first regulator onto the rice plants during the heading and flowering stages when the rice plants are experiencing high-temperature heat stress. A second regulator is sprayed 2 hours prior to the first regulator. The first regulator is sprayed daily for four consecutive days at a rate of 50 kg per mu (approximately 1.5 acre) and evenly applied to the rice plants. The second regulator is applied at a rate of 15 kg per mu (approximately 1.5 acre) and diluted with water (900 times the total weight of propylene glycol and humic acid) before spraying. The second regulator is evenly applied to the rice plants. Simultaneously, irrigation is performed during the period of high-temperature heat stress to maintain a watered state.

[0030] The first conditioning agent comprises 3 mmol / L methyl jasmonate, 25 mg / L tannic acid, 18 mg / L calcium nitrate, and 20 mg / L betaine, as well as a 35% ethanol solution, where the ethanol solution accounts for 0.3% of the total weight of the methyl jasmonate, tannic acid, calcium nitrate, and betaine. The ethanol solution serves as a developing agent to better disperse the ingredients in the first conditioning agent. The second conditioning agent is a mixture of propylene glycol and humic acid in a weight ratio of 1:15.

[0031] Comparative Example 1

[0032] The first conditioning agent does not contain tannic acid, and the other treatment methods are the same as those in Example 1.

[0033] Comparative Example 2

[0034] The first conditioning agent does not contain calcium nitrate, and the other treatment methods are the same as in Example 1.

[0035] Comparative Example 3

[0036] The first conditioning agent does not contain betaine, and other treatment methods are the same as in Example 1.

[0037] Comparative Example 4

[0038] The second conditioning agent does not contain humic acid, and the other treatment methods are the same as those in Example 1.

[0039] Comparative Example 5

[0040] The second conditioning agent does not contain propylene glycol, and the other treatment methods are the same as in Example 1.

[0041] Comparative Example 6

[0042] The first regulator and the second regulator were used simultaneously without a 1-hour interval. Other treatment methods were the same as in Example 1.

[0043] Comparative Example 7

[0044] Methyl jasmonate was used alone for treatment, that is, when the rice suffered from high temperature heat stress during the heading and flowering period, methyl jasmonate with a concentration of 1 mmol / L (containing 0.1% ethanol as a developing agent) was sprayed on the rice plants for 5 consecutive days, once a day, with a spraying amount of 40 kg / mu each time, and the rice plants were evenly sprayed during the spraying. At the same time, water was irrigated during the period when the rice suffered from high temperature heat stress to keep the rice plants in a watered state.

[0045] Comparative Example 8

[0046] Salicylic acid was used instead of methyl jasmonate, and other treatment methods were the same as in Example 1.

[0047] In order to illustrate the effect of the method of the present invention, the applicant conducted the following comparative test. The test was completed at the Rice Research Institute of Guangxi Academy of Agricultural Sciences. The heat-sensitive variety 9311 was selected as the test material. The seedlings with consistent growth were transplanted into barrels, with 3 holes in each barrel and 1 plant in each hole. Water and fertilizer management was carried out according to conventional cultivation methods, and treatment began when the seeds grew to the heading and flowering stage. The experiment was divided into 11 treatments and 1 blank group, with 5 pots in each treatment and 3 repetitions. The blank group was not treated at room temperature; each treatment was set at a high temperature of 38°C from 9:30 to 15:30 every day, with a temperature fluctuation of about 0.5°C, and was treated for 6 hours every day for 4 consecutive days. After 4 days, the material was moved outdoors to continue growing, and the pollen germination rate was measured during the peak flowering period of rice. The fruit set rate and 1000-grain weight were investigated and counted during the maturity period. The results are shown in Table 1.

[0048] The pollen germination rate was determined with reference to the article “Effects of high temperature stress during flowering on physiological characteristics of rice anthers and pollen traits” (Zhang Guilian, Zhang Shuntang, Xiao Langtao, Wu Xiaojin, Xiao Yinghui, Chen Liyun. Effects of high temperature stress during flowering on physiological characteristics of rice anthers and pollen traits [J]. Acta Agronomica Sinica, 2013, 39(1): 177-183). Liquid culture medium was prepared in advance, and pollen was collected for smearing on the morning of the 1st, 2nd and 3rd day after treatment. The slides were placed in culture dishes and kept moist at 30°C for 15 minutes. The pollen germination rate was detected under a microscope and the average value was calculated.

[0049] Treatment 1 adopts the method of Example 1, Treatment 2 adopts the method of Example 2, Treatment 3 adopts the method of Example 3, Treatment 4 adopts the method of Comparative Example 1, Treatment 5 adopts the method of Comparative Example 2, Treatment 6 adopts the method of Comparative Example 3, Treatment 7 adopts the method of Comparative Example 4, Treatment 8 adopts the method of Comparative Example 5, Treatment 9 adopts the method of Comparative Example 6, Treatment 10 adopts the method of Comparative Example 7, and Treatment 11 adopts the method of Comparative Example 8.

[0050] Table 1 Comparison of the effects of each group

[0051]

[0052]

[0053] Note: Different letters in each column indicate significant differences at the 5% level.

[0054] Comparison of the data of the examples and the blank group in the above table shows that the pollen germination rate, seed setting rate and 1000-grain weight of rice treated with the method of the present invention are not significantly different from those of rice grown under normal conditions, indicating that the method of the present invention can effectively alleviate high temperature heat damage to rice.

[0055] Comparison of the data in Example 1 and Comparative Examples 1 to 5 shows that tannic acid, calcium nitrate, betaine, propylene glycol, and humic acid have a synergistic effect and can be used together to improve the heat resistance of rice. Comparison of the data in Example 1 and Comparative Example 6 shows that spraying the second regulator before applying the first regulator can further improve the heat resistance of rice. Comparison of the data in Example 1 and Comparative Example 7 shows that the heat resistance of rice treated with methyl jasmonate alone does not significantly improve. Comparison of the data in Example 1 and Comparative Example 8 shows that the combination of tannic acid, calcium nitrate, betaine, propylene glycol, and humic acid is more suitable for the synergistic effect of methyl jasmonate, but not for the synergistic effect of salicylic acid.

[0056] In summary, the present invention sprays the second regulator before applying the first regulator, and the first regulator is tannic acid, calcium nitrate and betaine combined with the plant growth regulator methyl jasmonate, thereby solving the problem that the use of methyl jasmonate alone in alleviating high-temperature heat damage is unstable and inefficient.

[0057] Conclusion The foregoing description of specific exemplary embodiments of the present invention is for purposes of illustration and description. These descriptions are not intended to limit the invention to the precise forms disclosed, and it is apparent that many modifications and variations are possible in light of the foregoing teachings. The exemplary embodiments have been selected and described for the purpose of explaining the specific principles of the invention and their practical application, thereby enabling those skilled in the art to make and utilize a variety of exemplary embodiments of the invention and various options and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A method for alleviating high temperature heat damage to rice, characterized in that: When rice plants are subjected to high temperature heat stress during heading and flowering stages, a first regulator is sprayed on the rice plants, and a second regulator is sprayed before the first regulator is applied; The first regulator contains methyl jasmonate at a concentration of 1-4 mmol / L, tannic acid at a concentration of 10-40 mg / L, calcium nitrate at a concentration of 6-20 mg / L, and betaine at a concentration of 12-30 mg / L; The second regulator is mainly composed of a mixture of propylene glycol and humic acid in a weight ratio of 1:10-20.

2. The method for alleviating high temperature heat damage to rice according to claim 1, characterized in that: The high temperature heat stress refers to daytime temperatures exceeding 35°C for more than three consecutive days.

3. The method for alleviating high temperature heat damage to rice according to claim 1, characterized in that: The first regulator is sprayed continuously for 3-5 days, once a day, with a spraying amount of 40-60 kg / mu each time, and is evenly sprayed on the rice plants.

4. The method for alleviating high temperature heat damage to rice according to claim 1, characterized in that: The first regulator also contains an auxiliary agent, which is an ethanol solution with a mass concentration of 30-40%. The auxiliary agent accounts for 0.1-0.4% of the total weight of the methyl jasmonate, tannic acid, calcium nitrate and betaine.

5. The method for alleviating high temperature heat damage to rice according to claim 1, characterized in that: The second regulator is sprayed 1-3 hours before the first regulator is applied.

6. The method for alleviating high temperature heat damage to rice according to claim 1, characterized in that: The second regulator is diluted with water in an amount of 800-1000 times the total weight of propylene glycol and humic acid before spraying.

7. The method for alleviating high temperature heat damage to rice according to claim 1, characterized in that: The second regulator is sprayed at a rate of 10-20 kg / mu and is evenly sprayed on the rice plants.

8. The method for alleviating high temperature heat damage to rice according to claim 1, characterized in that: The method for alleviating high-temperature heat damage to rice further comprises irrigating the field during the period when the rice suffers from high-temperature heat damage stress to keep the field watered.

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