Method for relieving high-temperature heat damage to rice

Abstract

The invention discloses a method for relieving high-temperature heat damage to rice, and relates to the technical field of rice cultivation. The method for relieving the high-temperature heat damage to the rice comprises the steps that when the rice suffers from high-temperature heat damage stress in the heading and flowering period, a first conditioning agent is sprayed to rice plants, and a second conditioning agent is sprayed before the first conditioning agent is applied; the first conditioning agent contains methyl jasmonate with the concentration of 1-4 mmol / L, tannic acid with the concentration of 10-40 mg / L, calcium nitrate with the concentration of 6-20 mg / L and betaine with the concentration of 12-30 mg / L; the second conditioning agent is mainly formed by mixing propylene glycol and humic acid according to the weight ratio of 1: (10-20). The problems that the effect of relieving high-temperature heat damage by independently using methyl jasmonate is unstable and the efficiency is not high are solved.

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. It has developed a certain degree of adaptability to high temperature environments during its long evolution. However, when the external temperature is too high and exceeds the critical value for the optimal growth of rice, it will have an extremely adverse effect on the normal growth process of rice. Studies have found that high temperatures above 35°C during the reproductive growth period of rice will cause harm to rice, and every 1°C increase in temperature during this period will eventually lead to a 10% loss in yield. In recent years, frequent high temperature heat damage has seriously affected the yield and quality of rice.

[0003] The current methods for alleviating heat damage to rice mainly include planting heat-resistant rice varieties, sowing in stages, and applying plant growth regulators. However, there are few heat-resistant rice varieties, and different heat-resistant varieties have different heat-resistant periods. Some varieties are more heat-resistant during the flowering period, but poorly heat-resistant during the filling period, which is difficult to meet the use needs. In addition, the breeding cycle and time are long, making it difficult to use them quickly. Plant growth regulators are the most commonly used method. Many studies have disclosed the use of plant growth regulators to alleviate rice heat damage. These plant growth regulators include ABA, salicylic acid, 6-BA, 2,4-epibrassinolide, exogenous KT, etc. (CN 105210748B, CN 112385496 B, CN 116584268 A). The applicant discovered in previous studies 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 when 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 the 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 scheme is as follows:

[0006] A method for alleviating high temperature heat damage to rice, comprising spraying a first regulator on rice plants when the rice plants are subjected to high temperature heat damage stress during 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 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 sprayed evenly on the rice plants.

[0011] Furthermore, the first regulator also contains 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 is used as a developing agent to better disperse the raw materials in the first regulator.

[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 sprayed evenly 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 keep the field watered.

[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 in combination with plant growth regulator methyl jasmonate, thereby solving the problem that the effect of methyl jasmonate alone in alleviating high temperature heat damage is unstable and inefficient.

[0018] 2. Before applying the first regulator, the second regulator is sprayed first. The second regulator can enhance the efficacy 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 promote rice to resist high temperature stress, tannic acid can absorb part of the light, and can protect methyl jasmonate from being decomposed by light during use, resulting in reduced effect, calcium nitrate can be converted into nitric oxide by the plant body, and participate in the heat damage resistance reaction, betaine can stabilize the cell structure, and protect the enzyme activity, and tannic acid, calcium nitrate and betaine jointly improve the use effect of methyl jasmonate. Therefore, the joint action of tannic acid, calcium nitrate, betaine and methyl jasmonate improves the tolerance of rice to high temperature. 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, when the rice suffers from high temperature heat damage during heading and flowering period, spraying a first regulator on the rice plants, and spraying a second regulator 1 hour before applying the first regulator. The first regulator is sprayed continuously for 3 days, once a day, and the spraying amount is 60kg / mu each time, and the rice plants are evenly sprayed during the spraying. The second regulator is sprayed at a rate of 20kg / mu, and is diluted with water 1000 times the total weight of propylene glycol and humic acid before spraying, and is evenly sprayed on the rice plants during the spraying. At the same time, water is irrigated during the period when the rice suffers from high temperature heat damage to keep the rice plants in a water state.

[0024] The first regulator contains 4 mmol / L methyl jasmonate, 40 mg / L tannic acid, 20 mg / L calcium nitrate and 30 mg / L betaine, and contains 40% ethanol solution by mass, the ethanol solution accounts for 0.4% of the total weight of the methyl jasmonate, tannic acid, calcium nitrate and betaine, and the ethanol solution is used as a developing agent to better disperse the raw materials in the first regulator. The second regulator is a mixture of propylene glycol and humic acid in a weight ratio of 1:20.

[0025] Example 2

[0026] A method for alleviating high temperature heat damage to rice, when the rice suffers from high temperature heat damage during heading and flowering period, spraying a first regulator on the rice plants, and spraying a second regulator 3 hours before applying the first regulator. The first regulator is sprayed continuously for 5 days, sprayed once a day, and the spraying amount is 40kg / mu each time, and is evenly sprayed on the rice plants during spraying. The second regulator is sprayed at a rate of 10kg / mu, and is diluted with water 800 times the total weight of propylene glycol and humic acid before spraying, and is evenly sprayed on the rice plants during spraying. At the same time, irrigation is performed during the period when the rice suffers from high temperature heat damage to maintain a water state.

[0027] The first regulator contains 1 mmol / L methyl jasmonate, 10 mg / L tannic acid, 6 mg / L calcium nitrate and 12 mg / L betaine, and contains 30% ethanol solution by mass, the ethanol solution accounts for 0.1% of the total weight of the methyl jasmonate, tannic acid, calcium nitrate and betaine, and the ethanol solution is used as a developing agent to better disperse the raw materials in the first regulator. The second regulator 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, when the rice suffers from high temperature heat damage during heading and flowering period, spraying a first regulator on the rice plants, and spraying a second regulator 2 hours before applying the first regulator. The first regulator is sprayed continuously for 4 days, once a day, and the spraying amount is 50 kg / mu each time, and the rice plants are evenly sprayed during spraying. The second regulator is sprayed at a rate of 15 kg / mu, and is diluted with 900 times the total weight of propylene glycol and humic acid before spraying, and is evenly sprayed on the rice plants during spraying. At the same time, water is irrigated during the period when the rice suffers from high temperature heat damage to keep the rice plants in a water state.

[0030] The first regulator contains 3mmol / L methyl jasmonate, 25mg / L tannic acid, 18mg / L calcium nitrate and 20mg / L betaine, and contains 35% ethanol solution by mass, the ethanol solution accounts for 0.3% of the total weight of the methyl jasmonate, tannic acid, calcium nitrate and betaine, and the ethanol solution is used as a developing agent to better disperse the raw materials in the first regulator. The second regulator 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 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 other treatment methods are the same as those in Example 1.

[0035] Comparative Example 3

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

[0037] Comparative Example 4

[0038] The second regulator does not contain humic acid, and 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 processing methods are the same as those in Example 1.

[0041] Comparative Example 6

[0042] The first regulator and the second regulator are used simultaneously without an interval of 1 hour. Other treatment methods are the same as those in Example 1.

[0043] Comparative Example 7

[0044] Methyl jasmonate treatment was used alone, 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, and the spraying amount each time was 40 kg / mu, 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 it 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] To illustrate the effect of the method of the present invention, the applicant conducted the following comparative test, which was completed at the Rice Research Institute of Guangxi Academy of Agricultural Sciences. The heat-sensitive variety 9311 was selected as the test material, and 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 the treatment began when the seeds grew to the heading and flowering period. 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 38°C at 9:30-15:30 every day, with a temperature fluctuation of about 0.5°C, and treated for 6 hours every day, and the high temperature treatment was continued for 4 days. After 4 days, the material was moved outdoors for continued growth, and the pollen germination rate was measured during the peak flowering period of rice, and the fruit set rate and thousand-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 smear in the morning of the 1st, 2nd and 3rd day after treatment. The slides were placed in culture dishes and kept moisturized 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 embodiment and the blank group in the above table shows that the pollen germination rate, fruit setting rate and 1000-grain weight of rice treated by 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 better alleviate high temperature heat damage to rice.

[0055] The data comparison between 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 their joint use can improve the heat resistance of rice. The data comparison between 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. The data comparison between Example 1 and Comparative Example 7 shows that the heat resistance of rice treated with methyl jasmonate alone is not significantly improved. The data comparison between 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 second regulator is sprayed before the first regulator is applied in the present invention, and the first regulator is tannic acid, calcium nitrate and betaine used in combination with plant growth regulator methyl jasmonate, which solves the problem that the effect 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 the purpose of illustration and demonstration. These descriptions are not intended to limit the present invention to the precise form disclosed, and it is clear that many changes and variations can be made in accordance with the above teachings. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present invention and its practical application, so that those skilled in the art can realize and utilize various different exemplary embodiments of the present invention and various different selections and changes. The scope of the present invention is intended to be limited 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 period, the first regulator is sprayed on the rice plants, and the 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 propylene glycol and humic acid in a weight ratio of 1:10-20.

2. A 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 sprayed evenly 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%, and 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 sprayed evenly onto 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 also includes irrigating the field during the period when the rice is subjected to high temperature heat damage stress to keep the field watered.

Images