CN111418592B

CN111418592B - Low-temperature-resistant seed soaking agent for rice in germination stage, preparation method and application thereof

Info

Publication number: CN111418592B
Application number: CN202010205749.5A
Authority: CN
Inventors: 张桂莲; 张嘉伟; 唐文帮; 邹正
Original assignee: Hunan Agricultural University
Current assignee: Hunan Agricultural University
Priority date: 2020-03-23
Filing date: 2020-03-23
Publication date: 2021-07-02
Anticipated expiration: 2040-03-23
Also published as: CN111418592A

Abstract

The invention provides a low-temperature resistant seed soaking agent for a rice germination stage, a preparation method and application thereof, wherein the low-temperature resistant seed soaking agent for the rice germination stage is formed by mixing an abscisic acid solution with the mass concentration of 9-11 mg/L, a potassium dihydrogen phosphate solution with the mass concentration of 5-7 g/L and an uniconazole solution with the mass concentration of 29-31 mg/L, and the volume ratio of the abscisic acid solution, the potassium dihydrogen phosphate solution and the uniconazole solution is 2-4: 1-3: 0.5-1.5. The low-temperature resistant seed soaking agent for the rice in the germination stage can effectively improve the seedling rate and the strong seedling rate of rice seedlings at low temperature, reduce the damage of low temperature to the rice seedlings and achieve the effect of improving the low-temperature resistance of the rice seedlings.

Description

Low-temperature-resistant seed soaking agent for rice in germination stage, preparation method and application thereof

Technical Field

The invention relates to a low-temperature-resistant seed soaking agent for rice in a germination period, a preparation method and application thereof, and belongs to the technical field of agricultural production.

Background

In recent years, with the development of rural economy and the adjustment of industrial structure in China, a large number of rural young and middle-aged labor population enters cities, rural labor is greatly reduced and severely aged, so that a simplified rice cultivation technology capable of reducing labor consumption and labor intensity becomes a focus of general attention of modern rice and urgent needs of social development. Direct seeding is a simplified cultivation mode, is more and more favored by rice farmers due to the advantages of labor saving, cost saving, high efficiency, mechanization adaptation and the like, enlarges the double direct seeding area of early and late rice year by year, becomes a simplified and large-scale efficient planting mode in double cropping rice areas in south, and has important significance for promoting agricultural production mode transformation and ensuring national grain safety. The rice belongs to a short-day thermophilic crop, originates from tropical and subtropical regions, has higher temperature requirement compared with crops such as wheat, soybean and the like, and is not beneficial to the normal growth and development of the rice if the temperature is too low. The low-temperature cold damage occurs in each period of the growth and development of the rice, and influences of different degrees can be caused, so that the yield and the quality of the rice are reduced, and even grains are not harvested in severe cases, and the grain safety of China faces very serious challenges. According to statistics, the loss of paddy rice caused by low-temperature cold damage in China is nearly 50-100 hundred million kg every year. In double cropping rice regions in south China, the early rice sowing season often meets low-temperature rainy days, so that the emergence rate of direct seeding early rice is low, the emergence is irregular, and even large-area seed rotting buds appear, so that the yield of early rice is seriously influenced, and the late rice planting is influenced due to the delay of the growth period, so that the yield of late rice is reduced. The low seedling rate and irregular seedling emergence in the actual production are main limiting factors for limiting the high and stable yield of the direct-seeding early rice, and become bottlenecks for limiting the large-area popularization of the double direct seeding in double-cropping rice regions in south China. Therefore, the research on the cold resistance of the rice in the bud stage is developed, the emergence rate of the direct-seeding early rice is improved, the full-seedling sowing is realized, and the method has important significance for the safe production of the early indica rice in the middle and lower reaches of Yangtze river.

The research on the low-temperature cold damage reduction of the rice in the bud stage is carried out in the aspects of low-temperature resistant variety screening, water regulation, mulching film covering, seed initiation and the like at home and abroad. In the screening of low-temperature resistant varieties in the rice germination period, the screened low-temperature resistant varieties often have obvious regional differences and even have obvious differences among years. In production, no rice variety can be widely used for low-temperature environment production at home and abroad; the water regulation and control reduces the low-temperature cold damage of rice through reasonable irrigation, but for direct seeding early rice, the early stage seedling bed flooding irrigation is not favorable for rice germination and seedling emergence, so the heat preservation through the irrigation is not feasible. The mulching is adopted to cover the rice seedling, so that the low-temperature defense in the bud stage is facilitated, but the direct seeding of the early rice and the large-area covering film are not practical, and meanwhile, the rice photosynthesis can be seriously influenced by the mulching, and the rice growth is seriously damaged. Seed initiation can improve the low-temperature tolerance of rice, but improper use has the problems of phytotoxicity and high cost, and no universal, effective and applicable method is practically applied to reducing the low-temperature cold injury of rice in the bud stage in actual production so far.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a low-temperature resistant seed soaking agent in the rice germination period so as to effectively reduce the low-temperature cold damage of the rice in the rice germination period; the second purpose of the invention is to provide a preparation method of the low-temperature resistant seed soaking agent in the rice germination period; the invention also aims to provide the application of the low-temperature resistant seed soaking agent in the rice germination stage in reducing the low-temperature cold damage of the rice germination stage.

In order to solve the technical problems, the technical scheme of the invention is as follows:

a low-temperature-resistant seed soaking agent for rice in a germination stage is formed by mixing 9-11 mg/L of abscisic acid solution, 5-7 g/L of potassium dihydrogen phosphate solution and 29-31 mg/L of uniconazole solution, wherein the volume ratio of the abscisic acid solution to the potassium dihydrogen phosphate solution to the uniconazole solution is 2-4: 1-3: 0.5-1.5.

Further, the concentration of the abscisic acid solution is 10mg/L, the concentration of the potassium dihydrogen phosphate solution is 6g/L, the concentration of the uniconazole solution is 30mg/L, and the volume ratio of the abscisic acid solution to the potassium dihydrogen phosphate solution to the uniconazole solution is 2:1:0.5 or 3:2:1 or 4:3: 1.5. .

Based on the same inventive concept, the invention also provides: before use, an abscisic acid solution with the mass concentration of 9-11 mg/L, a potassium dihydrogen phosphate solution with the mass concentration of 5-7 g/L and an uniconazole solution with the mass concentration of 29-31 mg/L are prepared according to the volume ratio of 2-4: 1-3: 0.5-1.5 to form a mixed solution, and the low-temperature resistant seed soaking agent in the rice bud stage is obtained.

Preferably, the low-temperature resistant seed soaking agent in the rice germination period is prepared just in use, so that the effect is better; before blending, the abscisic acid solution is stored at low temperature, and the uniconazole solution and the potassium dihydrogen phosphate solution are stored away from light.

Further, the concentration of the abscisic acid solution is 10mg/L, the concentration of the potassium dihydrogen phosphate solution is 6g/L, and the concentration of uniconazole is 30 mg/L.

More preferably, the volume ratio of the abscisic acid solution, the potassium dihydrogen phosphate solution and the uniconazole solution is 2:1:0.5 or 3:2:1 or 4:3:1.5, preferably 3:2: 1.

Based on the same inventive concept, the invention also provides: the low-temperature resistant seed soaking agent for the rice sprout period or the low-temperature resistant seed soaking agent for the rice sprout period prepared by the preparation method is applied to reducing the low-temperature cold damage of the rice sprout period.

Further, soaking rice seeds in the low-temperature-resistant seed soaking agent at the rice germination stage for 47-49h at room temperature (25 ℃) or for 23-25h at 30 ℃, washing with water, accelerating germination and sowing; preferably, the ratio of the mass of the rice seeds to the volume of the low-temperature resistant seed soaking agent in the rice germination stage is 1:2.5-3.5, and further preferably 1: 3; preferably, the rice is direct-seeding early rice. Optionally, the sample is rinsed clean with tap water.

Further, the seed was soaked at room temperature (25 ℃) for 48 hours, or at 30 ℃ for 24 hours.

Further, the washed rice seeds are subjected to pregermination for 2-3d at 32 ℃ so that the sprouts are about 5mm long and the roots are about 2.5mm long.

Optionally, dry direct seeding or wet direct seeding is carried out on the sprouted grain obtained by germination acceleration, optionally, the seed consumption per mu is 3-6kg, and mechanical direct seeding or manual broadcasting, drill seeding or hole seeding modes can be adopted.

Generally, the low temperature of the invention refers to the low-temperature weather with the natural environment temperature of 6-10 ℃ and the duration of 3-12 days.

Abscisic acid is a relatively good cold-resistant agent which is generally accepted at present, but is not practical in actual large-area production due to high price. The inventor of the invention finds that abscisic acid and KH₂PO₄The seed soaking agent formed by ternary compounding with uniconazole in a specific ratio can obviously improve the low-temperature resistance regulation and control effect of the direct-seeded early rice. Experiments prove that the seed soaking agent has very obvious low-temperature resistance regulation and control effects on the rice germination stage, and shows a remarkable synergistic induction effect. Specifically, the uniconazole has the general effects of inhibiting cell elongation, shortening internodes and cultivating strong and short seedlings on crops; the potassium dihydrogen phosphate belongs to a high-efficiency phosphorus-potassium compound fertilizer, can provide P element and K element for seedling growth, can also improve the chlorophyll content, enhance photosynthesis and effectively promoteAnd (5) growing and developing the root system. In conventional studies, the low temperature induction resistant effects of the two on crops are not significant. The inventor of the invention finds that KH₂PO₄Shows unexpected low temperature control effect on a special object of the rice sprouting period, and has uniconazole and KH₂PO₄The seed soaking agent and the abscisic acid are compounded according to the proportion of the invention, so that the low temperature resistance regulation effect of the seed soaking agent on the rice germination period can be obviously improved. Test results show that the seedling rate of the rice in the bud stage regulated and controlled by the seed soaking agent is 87.99 percent, and the abscisic acid, the uniconazole, the abscisic acid and the KH are₂PO₄The survival rates of the binary compound regulation and control are respectively 50.66 percent and 49.34 percent, and the difference is obvious. The uniconazole, the monopotassium phosphate and the ABA have a synergistic cold-resistant regulation effect, the stem base width, the total root number, the root dry weight and the protective enzyme activity of the buds can be obviously improved, the malonaldehyde content and the relative conductivity are reduced, and the cell membrane structure and the cell membrane function are relatively stable, so that the cold-resistant synergistic regulation effect is obviously superior to that of abscisic acid and uniconazole, and abscisic acid and KH₂PO₄The binary compound agent has the regulation and control effect.

Compared with the prior art, the invention has the following advantages:

1. the low-temperature resistant seed soaking agent for the rice in the germination period can obviously improve the activity of rice seedling protective enzyme, reduce the content of malonaldehyde and relative conductivity, and maintain the structure and function of a cell membrane relatively stable; the growth of root systems can be promoted, the thickness and the total number of main roots are increased, the activity of the root systems of the seedlings is improved, and the normal supply of water on the overground parts of the seedlings is maintained; in addition, the stem base thickness of the seedling can be increased, so that the seedling is short and strong, the seedling rate of the rice seedling at low temperature is increased, the damage of the low temperature to the rice seedling is reduced, and the effect of improving the low temperature resistance of the rice seedling is achieved.

2. Experiments prove that for direct-seeding early rice varieties, the low-temperature seed soaking agent for the rice in the germination period is used for accelerating germination after seed soaking before direct seeding, so that the damage of the low temperature in the germination period to rice germination and seedling emergence can be reduced to the greatest extent; for early rice varieties which are raised in seedling trays or raised in fields, the low-temperature seed soaking agent for the rice in the germination period is used for soaking seeds before accelerating germination, so that the damage of the low temperature in the germination period to the germination and seedling emergence of the rice can be reduced to the greatest extent. Meanwhile, under the condition of low temperature in the later seedling stage, the harm of the low temperature in the seedling stage to the rice seedlings can be reduced.

3. The low-temperature seed soaking agent for the rice in the germination period is prepared by compounding common raw materials, is low in price and is simple and convenient to operate.

Drawings

FIG. 1 is a graph showing the effect of different seed soaking patterns on the seedling rate at room temperature;

note: the seed soaking agent is used for soaking seeds for 48h, namely, the seed soaking agent solution is used for directly soaking the seeds for 48 h; the step of soaking the seeds in water for 24h + the seed soaking agent for 24h means that the seeds are soaked in water for 24h, and then the seeds are soaked in the seed soaking agent solution for 24 h; the seed soaking agent is used for 24h + the water is used for 24h, namely, the seed is soaked by the seed soaking agent solution for 24h, and then the seed is soaked by the water for 24 h; soaking the seeds in water for 48h means soaking the seeds in water directly for 48 h.

FIG. 2 is a graph showing the effect of different seed soaking times on the seedling rate at room temperature.

FIG. 3 is a graph showing the effect of different cold treatment days on the seedling rate.

FIG. 4 is a photograph of shoots before cryogenic treatment, viewed from above, with the first row being a control group and the second row being a seed-soaking group.

FIG. 5 is a photograph of sprouts obtained at day 7 of the low-temperature treatment, wherein the first row is a seed-soaking group using a seed-soaking agent, and the second row is a control group, as viewed from above.

FIG. 6 is a photograph of sprouts recovered for 5 days after the low-temperature treatment for 7 days, wherein the first row is a seed-soaking group by the seed-soaking agent and the second row is a control group, as viewed from above.

Detailed Description

The invention is further described below with reference to specific preferred embodiments, without thereby limiting the scope of protection of the invention.

1. Selection of rice varieties

In the double-cropping rice region in Yangtze river valley, in order to ensure normal heading and maturity of late rice, early rice varieties with short growth period, high yield, high quality and strong stress resistance, such as Xiang early indica No. 45, Xiang early indica No. 6, Zhongjia early 17, Huanghuazhan and the like, should be selected, and the variety selected in the test is Xiang early indica No. 45 which is widely popularized in the current production.

2. Selection of seed soaking agent dosage and formula

(1) Single agent low temperature resistance test

The method comprises the steps of selecting full and healthy rice seeds, soaking the seeds for 24 hours at the temperature of 30 ℃ by using potassium dihydrogen phosphate, uniconazole and abscisic acid solutions with different concentrations, soaking the seeds by using clear water as a control, washing the seeds clean by using distilled water after soaking the seeds, accelerating germination for 2-3 days in a constant temperature box at the temperature of 32 ℃, and transferring the seeds to an illumination incubator at the temperature of 5 ℃ for low-temperature treatment for 7 days when the seeds are about 5mm in length and the roots are about 2.5mm in length. After the treatment, the temperature of the incubator is adjusted to 25 ℃, so that the rice sprouts can recover normal growth for 7d, then the number of surviving seedlings is investigated, the seedling rate is calculated, and the process is repeated for 4 times. The seedling rate is used as the evaluation index of the cold resistance in the bud stage. The seedling formation rate (%) × (number of surviving seedlings/total number of germinated seeds) × 100%. The results are shown in Table 1.

TABLE 1 results of single agent low temperature resistance experiments

Note: the data in the table are the average of 4 replicates. The lower case letters a, b, c, d, etc. following the data in the table are statistically used to indicate whether the inter-treatment differences are significant, different lower case letters indicate that the inter-treatment differences are significant at a level of 5%, and the same letters indicate that the inter-treatment differences are not significant at a level of 5%, which is a commonly used representation method in natural science research.

As can be seen from the table 1, the abscisic acid, the monopotassium phosphate and the uniconazole solution can improve the seedling rate of the sprouts subjected to low-temperature stress, the ABA solution with the best overall effect can improve the seedling rate of the sprouts subjected to low-temperature stress in the early indica No. 45 bud stage by more than 40% through concentration treatment; wherein, the treatment effect is best with 10mg/L abscisic acid solution, and the promotion is up to 60%. Now, 10mg/LABA solution and 6g/L KH solution are selected₂PO₄The solution and 30mg/L uniconazole solution are subjected to the next step of screening mixed control agents.

(2) Low temperature resistance test of mixed agent

Selecting full and healthy rice seeds, adding 10mg/L ABA solution and 6g/L KH₂PO₄Solution, 30mg/L uniconazole solution (A, B, C instead of the above solution, respectively.) per solutionPreparing different mixing agents for 2 and 3 seeds according to a certain volume ratio, soaking the seeds for 24 hours at the temperature of 30 ℃, soaking the seeds with clear water as a contrast, washing the seeds clean with distilled water after soaking, accelerating germination for 2-3 days in a constant temperature box at the temperature of 32 ℃, and transferring the seeds to a light incubator at the temperature of 5 ℃ for low-temperature treatment for 7 days when the sprouts are about 5mm long and the roots are about 2.5mm long. After the treatment, the temperature of the incubator is adjusted to 25 ℃, so that the rice sprouts can recover normal growth for 7d, then the number of surviving seedlings is investigated, the seedling rate is calculated, and the process is repeated for 4 times. The seedling rate is used as the evaluation index of the cold resistance in the bud stage. The seedling formation rate (%) × (number of surviving seedlings/total number of germinated seeds) × 100%. The results are shown in Table 2.

TABLE 2 Low temperature resistance test results for the blends

Note: the lower case letters a, b, c, d, etc. following the data in table 2 are statistically used to indicate whether the inter-treatment differences were significant, different lower case letters indicate that the inter-treatment differences were significant at a level of 5%, and the same letters indicate that the inter-treatment differences were not significant at a level of 5%, which is a commonly used representation in natural science research.

As can be seen from Table 2, compared with the control group, the mixed solutions with different proportions can significantly improve the seedling rate of the early indica Xiang No. 45 after suffering from low-temperature stress in the bud stage, wherein the mixed solvent with the best effect is ABC mixed solution (10mg/L ABA solution, 6g/L KH solution)₂PO₄The mixed solution of the solution and 30mg/L uniconazole solution prepared according to the volume ratio of 3:2: 1) has the seedling rate of 87.99 percent, has larger amplitude of improving the seedling rate than the single-agent spraying and other mixed solutions with the mixture ratio and has good effect.

3. Seed soaking mode of seed soaking agent and seed soaking time selection experiment

Based on the above results, a seed-soaking agent solution (10mg/L ABA solution, 6g/L KH) was selected for the full and healthy rice seeds₂PO₄Mixed solution prepared by the solution and 30mg/L uniconazole solution according to the volume ratio of 3:2: 1) is used for seed soaking, the seed soaking mode is set as seed soaking based on completely submerging seedsDirectly soaking seeds in the seed soaking agent solution for 48 hours, soaking the seeds in water for 24 hours, soaking the seeds in the seed soaking agent solution for 24 hours, soaking the seeds in water for 24 hours, and soaking the seeds in water for 48 hours, wherein the seed soaking time is set to be 12 hours, 24 hours, 36 hours, 48 hours, 60 hours and 72 hours, soaking the seeds in clear water as a control, washing the seeds clean with distilled water after soaking the seeds, accelerating germination in a constant temperature box at 32 ℃ for 2-3 days, and transferring the seeds to a light culture box at 5 ℃ for low-temperature treatment for 7 days when the sprouts are about 5mm in length and the roots are about 2.5mm in length. After the treatment, the temperature of the incubator is adjusted to 25 ℃, so that the rice sprouts can recover normal growth for 7d, then the number of surviving seedlings is investigated, the seedling rate is calculated, and the process is repeated for 4 times. The seedling rate is used as the evaluation index of the cold resistance in the bud stage. The seedling formation rate (%) × (number of surviving seedlings/total number of germinated seeds) × 100%. The results are shown in FIGS. 1 and 2.

As can be seen from FIG. 1, different seed soaking modes have influence on the seedling rate under low temperature stress in the bud stage, the seedling rate is the highest when the seed soaking agent directly soaks the seeds for 48h, and the seedling rate is the lowest when the seeds are soaked in the water for 48h in a mode that the seeds are soaked in clear water for 24h and then the seed soaking agent is used for soaking the seeds for 24 h. As can be seen from figure 2, the early indica Xiang No. 45 seeds are soaked in the seed soaking agent at room temperature for different times, the seedling rate is different after low-temperature stress, and the seedling rate is the highest and the best effect is achieved by directly soaking the seeds in the seed soaking agent for 48 hours.

4. Selection experiment of low temperature treatment time

Based on the above results, a seed-soaking agent solution (10mg/L ABA solution, 6g/L KH) was selected for the full and healthy rice seeds₂PO₄Mixed solution prepared by mixing the solution and 30mg/L uniconazole solution according to a ratio of 3:2: 1) for 48 hours, taking the seeds completely submerged, taking clear water for seed soaking as a reference, washing the seeds completely by using distilled water after seed soaking, accelerating germination in a constant temperature box at 32 ℃ for 2-3 days, transferring the seeds to a light incubator at 5 ℃ for low-temperature treatment when the sprouts are about 5mm long and the roots are about 2.5mm long, setting the low-temperature treatment time to be 3d, 5d, 7d and 10d, adjusting the temperature of the incubator to 25 ℃ after the treatment is finished, restoring the normal growth of the rice sprouts for 7d, investigating the number of survival seedlings, calculating the seedling rate, and repeating for 4 times. The seedling rate is used as the evaluation index of the cold resistance in the bud stage. The seedling formation rate (%) × (number of surviving seedlings/total number of germinated seeds) × 100%. The results can be seen from FIG. 3, with lowThe number of days of warm stress is increased, the seedling rate of Xiangzaixuan No. 45 is gradually reduced, the low-temperature stress is 7 days, the seedling rate of Xiangzaixuan No. 45 of seed soaking by the seed soaking agent is 88 percent, the seedling rate of contrast water soaking is 10.68 percent, the low-temperature stress is 10 days, the seedling rate of Xiangzaixuan No. 45 of seed soaking by the seed soaking agent is 80 percent, the seedling rate of contrast water soaking is 0, and the difference reaches an extremely obvious level.

5. Artificially simulated low-temperature and seed soaking agent treatment experiment

(1) Influence of seed soaking agents with different proportions on rice seedling rate under low-temperature stress in bud stage

Selecting healthy and plump early indica Xiang No. 45 seeds, adding 10mg/L ABA solution and 6g/L KH₂PO₄Soaking seeds for 48 hours by using three mixed solutions prepared by 30mg/L uniconazole solution according to the volume ratio of 2:1:0.5, 3:2:1 and 4:3:1.5, taking the seeds completely submerged as the standard, soaking the seeds by using clear water as a control, washing the seeds by using distilled water after soaking the seeds, accelerating germination for 2-3d in a constant temperature box at 32 ℃, transferring the seeds to a lighting incubator at 5 ℃ for low-temperature treatment for 10d when the sprouts are about 5mm in length and about 2.5mm in root length, adjusting the temperature of the incubator to 25 ℃ after the treatment is finished, restoring the normal growth of the rice sprouts for 7d, investigating the number of seedlings, calculating the seedling rate and repeating for 4 times. The seedling rate is used as the evaluation index of the cold resistance in the bud stage. The seedling formation rate (%) × (number of surviving seedlings/total number of germinated seeds) × 100%. The results are shown in Table 3.

TABLE 3 influence of seed soaking agent of different proportions on the seedling rate of rice seedlings at low temperature

Reagent collocation	Ratio of	Percent seedling rate (%)
			ABC	2:1:0.5	85.34a
ABC	3:2:1	87.99a
			ABC	4:3:1.5	86.89a
Distilled water (CK)		10.53b

Note: ABC represents 10mg/L ABA solution and 6g/L KH solution₂PO₄Solution, 30mg/L uniconazole solution.

The lower case letters a, b following the data in table 3 are statistically used to indicate whether the inter-treatment difference is significant, different lower case letters indicate that the inter-treatment difference is significant at a level of 5%, and the same letter indicates that the inter-treatment difference is not significant at a level of 5%, which is a commonly used representation method in natural science research.

As can be seen from table 3, the difference between the 3 seed soaking agents and distilled water (CK) reaches a significant level of 5%, and the difference between the 3 seed soaking agents is not significant.

(2) Influence of seed soaking agent on physiological characteristics of rice sprouts under low-temperature stress in bud stage

Selecting healthy and plump early indica Xiang No. 45 seeds, adding 10mg/L ABA solution and 6g/L KH₂PO₄Soaking seeds for 48 hours at room temperature (25 ℃) by a seed soaking agent solution prepared by a 30mg/L uniconazole solution according to a ratio of 3:2:1, taking the seeds completely submerged, taking clear water for soaking the seeds as a control, washing the seeds clean by distilled water after soaking the seeds, accelerating germination in a constant temperature box at 32 ℃ for 2-3 days until the length of the buds is about 5mm and the length of the roots is about 2.5mmTransferring the rice seedlings to a 5 ℃ illumination incubator for low-temperature treatment for 7d, adjusting the incubator temperature to 25 ℃ after the treatment to enable the rice seedlings to recover to normal growth for 7d, sampling the rice seedlings for detection of Malondialdehyde (MDA) content, relative conductivity, SOD activity, soluble sugar content and amylase activity before the low-temperature treatment, at the 7 th d of the low-temperature treatment and at the 5d of the recovery after the treatment, and investigating seedling rate, stem base width, bud fresh weight, bud dry weight, root fresh weight, root dry weight, total root number and longest root length after the treatment for 5d, wherein the results are shown in figures 4-6, tables 4 and 5.

TABLE 4 influence of seed soaking agent seed soaking on growth of rice sprouts under Low temperature stress

TABLE 5 influence of seed soaking agent seed soaking on physiological characteristics of rice shoots under Low temperature stress

Note: the lower case letters a, b following the data in table 4 are statistically used to indicate whether the inter-treatment difference is significant, different lower case letters indicate that the inter-treatment difference is significant at a level of 5%, and the same letter indicates that the inter-treatment difference is not significant at a level of 5%, which is a commonly used representation method in natural science research.

As can be seen from fig. 4 to 6, the shoot buds of the seed-soaking agent soaked seeds are shorter but stronger than those of the control before the low-temperature treatment; on day 7 of the low temperature treatment, there was no significant change compared to before treatment; the seedlings are recovered for 5 days after being treated at low temperature for 7 days, and compared with a control, the difference is obvious, the seedling rate of the seedlings soaked by the seed soaking agent is high, the seedlings are high in height, thick in stem and large in total number.

As can be seen from table 4, after 7 days of low-temperature treatment and 5 days of recovery, compared with the control, the seed soaking agent can improve the height of the young sprout, the width of the stem base, the leaf age, the fresh weight of the sprout, the dry weight of the sprout, the fresh weight of the root, the dry weight of the root, the total number of the roots, the longest length of the roots and the seedling rate, particularly the plant height, the width of the stem base, the total number of the roots, the fresh weight of the roots, the dry weight of the roots, the seedling rate and other indexes are obviously improved, and the stem base width, the total number of the roots, the fresh weight of the roots, the dry weight of the roots and the seedling rate are respectively improved by 67%, 117.41%.

As can be seen from Table 5, the MDA content, the relative conductivity, the SOD activity, the soluble sugar content and the amylase activity of the sprouts soaked by the seed soaking agent are not obviously changed compared with the control before the low-temperature treatment; on the 7 th day of low-temperature treatment, compared with a control, the MDA content and the relative conductivity of the sprouts soaked by the seed soaking agent are reduced by 29.31 percent and 15.28 percent respectively; and the SOD activity, the content of soluble sugar and the amylase activity are respectively increased by 24.56 percent, 53.71 percent and 79.75 percent compared with the control. Recovering for 5 days after low-temperature treatment for 7 days, and reducing the MDA content and the relative conductivity of the sprouts soaked by the seed soaking agent by 27.38 percent and 16.76 percent compared with those of the control; and the SOD activity, the content of soluble sugar and the amylase activity are respectively increased by 17.23 percent, 26 percent, 53 percent and 50.56 percent compared with the control.

As can be seen, under the condition of low temperature stress in the bud stage, 6g/L KH is added with 10mg/L ABA solution₂PO₄The seed soaking agent solution prepared by the solution and 30mg/L uniconazole solution according to the proportion of 3:2:1 is used for soaking seeds, so that the MDA content and the relative conductivity of the sprouts can be reduced, the SOD activity, the soluble sugar content and the amylase activity of the sprouts can be increased, the seedling rate of the sprouts can be improved, and the harm of low temperature in the sprouting period to the rice sprouts can be reduced.

In the test, an ABA solution containing 10mg/L and KH containing 6g/L was used₂PO₄The seed soaking agent solution is prepared by the solution and 30mg/L uniconazole solution according to the proportion of 3:2:1 for seed soaking, and if the germination period does not meet low temperature weather, but the seedling period meets low temperature, the effect of improving the low temperature resistance of the rice in the seedling period can be achieved. Simultaneously, for seedling tray seedling raising and field seedling raising, 10mg/L ABA solution and 6g/L KH solution are used₂PO₄The seed soaking agent solution prepared by the solution and 30mg/L uniconazole solution according to the proportion of 3:2:1 is used for soaking seeds, and the effect of improving the low temperature resistance of rice in the bud stage and the seedling stage in low temperature weather can be achieved.

The above description is only for the preferred embodiment of the present application and should not be taken as limiting the present application in any way, and although the present application has been disclosed in the preferred embodiment, it is not intended to limit the present application, and those skilled in the art should understand that they can make various changes and modifications within the technical scope of the present application without departing from the scope of the present application, and therefore all the changes and modifications can be made within the technical scope of the present application.

Claims

1. The low-temperature-resistant seed soaking agent for the rice in the germination stage is characterized by being prepared by mixing 10mg/L of abscisic acid solution, 6g/L of potassium dihydrogen phosphate solution and 30mg/L of uniconazole solution, wherein the volume ratio of the abscisic acid solution to the potassium dihydrogen phosphate solution to the uniconazole solution is 3:2: 1.

2. A preparation method of a low-temperature resistant seed soaking agent for a rice germination stage is characterized in that before use, a mixed solution is formed by preparing 10mg/L abscisic acid solution, 6g/L potassium dihydrogen phosphate solution and 30mg/L uniconazole solution according to the volume ratio of 3:2:1, and the low-temperature resistant seed soaking agent for the rice germination stage is obtained.

3. The use of the cold-resistant seed soaking agent for rice sprout period according to claim 1 or the cold-resistant seed soaking agent for rice sprout period prepared by the preparation method according to any one of claim 2 for reducing cold damage of rice sprout period.

4. The use as claimed in claim 3, wherein the rice seeds are immersed in the low temperature resistant seed soaking agent at the rice germination stage, soaked for 47-49h at room temperature or soaked for 23-25h at 30 ℃, washed with water, pregerminated, and sowed; the ratio of the mass of the rice seeds to the volume of the low-temperature resistant seed soaking agent in the rice germination stage is 1: 2.5-3.5.

5. The use of claim 4, wherein the ratio of the mass of the rice seed to the volume of the cold resistant seed soaking agent at the rice germination stage is 1: 3.

6. The use according to claim 4, wherein the seed is soaked for 48h at room temperature or for 24h at 30 ℃.

7. The use of claim 4, wherein the washed rice seeds are pregerminated at 32 ℃ for 2-3 days.

8. The use according to claim 4, wherein the rice is direct-seeded early rice.