Planting method for reducing antimony content in rice grains

Abstract

The invention relates to a planting method for reducing the antimony content in rice grains. The method comprises the following steps that sepiolite is applied to soil in a planting pot and fully stirred, and then rice is transplanted into the planting pot; in the rice growth period, nutrients are regularly added into the soil, and a proper amount of accumulated water is kept on the surface of the soil; harvesting when rice ears are golden yellow and full, so as to obtain rice grains with lower antimony content. The method can safely and effectively reduce the antimony content in the rice growing in the antimony-polluted soil, has the advantages of being easy to operate, low in cost and free of pollution, and meets the green and environment-friendly requirements.

Description

Technical Field

[0001] The invention relates to the field of improving heavy metal pollution of rice, and in particular to a planting method for reducing the antimony content in rice grains. Background Art

[0002] Sb (antimony) and its compounds have been confirmed to be a class of genotoxic substances. Due to human activities and the widespread use of Sb compounds, the Sb pollution problem has become increasingly serious. In view of the potential chronic toxicity and carcinogenicity of Sb to animals, plants and humans, foreign countries have paid more and more attention to the research on Sb pollution. Sb has been listed as a priority pollutant by the US Environmental Protection Agency and the Council of the European Community, and is also a pollutant closely monitored by the Japanese Environment Agency. However, although China is an important Sb reserve and production country, there is relatively little research on environmental Sb pollution, especially research on the improvement of rice field pollution is not comprehensive.

[0003] As one of the main food crops in my country, rice is often reported to contain excessive amounts of heavy metals. Therefore, repairing heavy metal-contaminated soil and reducing heavy metal enrichment in rice are crucial to ensuring safe food production in farmland. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] The technical problem to be solved by the present invention is to improve the influence of antimony-contaminated soil on rice growth and reduce the antimony content of rice grains.

[0006] (II) Technical solution

[0007] In order to solve the above technical problems, the present invention provides a planting method for reducing the antimony content in rice grains. The planting soil is antimony-contaminated soil and the rice planting method in pots is adopted, which comprises the following steps: firstly applying sepiolite to the planting soil in the planting pot, stirring evenly, and then transplanting the rice into the planting pot; during the rice planting, applying nutrients to the soil and keeping water on the soil surface; harvesting when the rice ears are golden and full, so as to obtain rice grains with low antimony content.

[0008] Preferably, the concentration of antimony in the antimony-contaminated soil is 100-400 mg / kg.

[0009] Preferably, the antimony in the antimony-contaminated soil is trivalent antimony.

[0010] Preferably, the planting pot has a size of 29 cm×20 cm and a height of 18 cm, and each planting pot is used to plant two rice plants with a spacing of 9 cm.

[0011] Preferably, the application amount of the sepiolite is 1% to 5% of the dry weight of the planting soil.

[0012] Preferably, sepiolite is applied to the planting soil in the planting pot for 30 days or more before transplanting the rice into the planting pot.

[0013] Preferably, the sepiolite is natural sepiolite with a mesh size of 200.

[0014] Preferably, the nutrients include at least one of quick-acting nitrogen fertilizer, quick-acting phosphorus fertilizer, and quick-acting potassium fertilizer.

[0015] Preferably, the depth of water accumulation on the soil surface is 2 to 3 cm.

[0016] Preferably, the antimony content in the rice grains is 0.056-0.073 mg / kg.

[0017] (III) Beneficial effects

[0018] The above technical solution of the present invention has the following advantages:

[0019] The present invention uses sepiolite to change the activity of heavy metals through its surface adsorption, ion exchange, coprecipitation and chemical adsorption mechanisms, so as to passivate heavy metals and reduce the enrichment of Sb by animals and plants, thereby reducing the toxic effects of Sb. The sepiolite used in the present invention is a clay mineral, which has the advantages of being fast, cheap and easy to operate in the passivation and remediation of heavy metal-contaminated soil, and can also improve the soil's granular structure and make the soil looser. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a diagram showing the effect of the present invention on the aboveground biomass of rice in soils contaminated with antimony at different concentrations;

[0021] Figure 2 This is a diagram showing the effect of the present invention on rice underground biomass in soils contaminated with antimony at different concentrations;

[0022] Figure 3 This is a graph showing the effect of the present invention on the MDA content of rice roots in soils contaminated with antimony at different concentrations;

[0023] Figure 4 This is a graph showing the effect of the present invention on the SOD content of rice roots in soils contaminated with antimony at different concentrations;

[0024] Figure 5 This is a graph showing the effect of the present invention on the POD content of rice roots in soils contaminated with antimony at different concentrations;

[0025] Figure 6 This is a graph showing the effect of the present invention on the CAT content of rice roots in soils contaminated with antimony at different concentrations;

[0026] Figure 7 This is a graph showing the effect of the present invention on the antimony content of rice grains in soils contaminated with antimony at different concentrations. DETAILED DESCRIPTION

[0027] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0028] Example 1

[0029] This embodiment provides a planting method for reducing the antimony content in rice grains. The antimony treatment concentration is set to 100 mg / kg (that is, the concentration of trivalent antimony in the soil is set to 100 mg / kg), and the amount of sepiolite applied is 10 g / kg (1% of the dry weight of the soil), which is recorded as H10. The specific steps are:

[0030] First, the uncontaminated soil (taken from Jiuer Modern Agricultural Industrial Park, Loudi City, Hunan Province) was naturally air-dried and sieved (4mm) before being placed in plastic basins (size 29cm×20cm, height 18cm), with 7kg of soil in each basin. A small amount of soil was taken to measure the soil physical and chemical indicators. Then, potassium antimony tartrate (Sb 3+ , analytically pure) solid powder, the concentration of trivalent antimony in the soil after application was 100 mg / kg; after aging for 30 days, sepiolite with a mesh size of 200 was applied, and 3 repetitions were set up, with a total of 3 pots; after applying the sepiolite, it was aged for another 30 days for use.

[0031] After 30 days of rice seedling cultivation, select healthy and uniform seedlings and transplant them into plastic pots, with 2 plants in each pot. Grow them under natural light and temperature conditions, and supplement water with distilled water every day. Apply 0.12 g / kg of urea to each pot during the tillering and heading stages to ensure consistent water and fertilizer, keep the soil surface water at 2 cm, and manage the rest normally. Harvest when the rice ears are golden and full to obtain rice grains with low antimony content.

[0032] Example 2

[0033] This embodiment provides a planting method for reducing the antimony content in rice grains. The antimony treatment concentration is set to 100 mg / kg (that is, the concentration of trivalent antimony in the soil is set to 100 mg / kg), and the amount of sepiolite applied is 30 g / kg (3% of the dry weight of the soil), recorded as H30. The specific steps are consistent with those in Example 1. The rice ears are harvested when they are golden and full, and rice grains with low antimony content are obtained.

[0034] Example 3

[0035] This embodiment provides a planting method for reducing the antimony content in rice grains. The antimony treatment concentration is set to 100 mg / kg (that is, the concentration of trivalent antimony in the soil is set to 100 mg / kg), and the amount of sepiolite applied is 50 g / kg (5% of the dry weight of the soil), which is recorded as H50. The specific steps are consistent with those in Example 1. The rice ears are harvested when they are golden and full, and rice grains with low antimony content are obtained.

[0036] Example 4

[0037] This embodiment provides a planting method for reducing the antimony content in rice grains. The antimony treatment concentration is set to 200 mg / kg (that is, the concentration of trivalent antimony in the soil is set to 200 mg / kg), and the amount of sepiolite applied is 10 g / kg (1% of the dry weight of the soil), which is recorded as H10. The specific steps are consistent with those in Example 1. The rice ears are harvested when they are golden and full, and rice grains with low antimony content are obtained.

[0038] Example 5

[0039] This embodiment provides a planting method for reducing the antimony content in rice grains. The antimony treatment concentration is set to 200 mg / kg (that is, the concentration of trivalent antimony in the soil is set to 200 mg / kg), and the amount of sepiolite applied is 30 g / kg (3% of the dry weight of the soil), recorded as H30. The specific steps are consistent with those in Example 1. The rice ears are harvested when they are golden and full, and rice grains with low antimony content are obtained.

[0040] Example 6

[0041] This embodiment provides a planting method for reducing the antimony content in rice grains. The antimony treatment concentration is set to 200 mg / kg (that is, the concentration of trivalent antimony in the soil is set to 200 mg / kg), and the amount of sepiolite applied is 50 g / kg (5% of the dry weight of the soil), which is recorded as H50. The specific steps are consistent with those in Example 1. The rice ears are harvested when they are golden and full, and rice grains with low antimony content are obtained.

[0042] Example 7

[0043] This embodiment provides a planting method for reducing the antimony content in rice grains. The antimony treatment concentration is set to 400 mg / kg (that is, the concentration of trivalent antimony in the soil is set to 400 mg / kg), and the amount of sepiolite applied is 10 g / kg (1% of the dry weight of the soil), which is recorded as H10. The specific steps are consistent with those in Example 1. The rice ears are harvested when they are golden and full, and rice grains with low antimony content are obtained.

[0044] Example 8

[0045] This embodiment provides a planting method for reducing the antimony content in rice grains. The antimony treatment concentration is set to 400 mg / kg (that is, the concentration of trivalent antimony in the soil is set to 400 mg / kg), and the amount of sepiolite applied is 30 g / kg (3% of the dry weight of the soil), recorded as H30. The specific steps are consistent with those in Example 1. The rice ears are harvested when they are golden and full, and rice grains with low antimony content are obtained.

[0046] Example 9

[0047] This embodiment provides a planting method for reducing the antimony content in rice grains. The antimony treatment concentration is set to 400 mg / kg (that is, the concentration of trivalent antimony in the soil is set to 400 mg / kg), and the amount of sepiolite applied is 50 g / kg (5% of the dry weight of the soil), which is recorded as H50. The specific steps are consistent with those in Example 1. The rice ears are harvested when they are golden and full, and rice grains with low antimony content are obtained.

[0048] Comparative Example 1

[0049] This comparative example provides a rice planting method, in which the antimony treatment concentration is set to CK mg / kg (no potassium antimony tartrate is applied), the amount of sepiolite applied is 0, recorded as H0, and the specific steps are consistent with those in Example 1. The rice ears are harvested when they are golden and full to obtain rice grains.

[0050] Comparative Example 2

[0051] This comparative example provides a planting method for reducing the antimony content in rice grains. The antimony treatment concentration is set to CK mg / kg (no potassium antimony tartrate is applied), and the amount of sepiolite applied is 10 g / kg (1% of the dry weight of the soil), which is recorded as H10. The specific steps are consistent with those in Example 1. The rice ears are harvested when they are golden and full to obtain rice grains.

[0052] Comparative Example 3

[0053] This comparative example provides a planting method for reducing the antimony content in rice grains. The antimony treatment concentration is set to CK mg / kg (no potassium antimony tartrate is applied), and the amount of sepiolite applied is 30 g / kg (3% of the dry weight of the soil), recorded as H30. The specific steps are consistent with those in Example 1. The rice ears are harvested when they are golden and full to obtain rice grains.

[0054] Comparative Example 4

[0055] This comparative example provides a rice planting method, in which the antimony treatment concentration is set to CK mg / kg (no potassium antimony tartrate is applied), the amount of sepiolite applied is 50 g / kg (5% of the dry weight of the soil), recorded as H50, and the specific steps are consistent with those in Example 1. The rice ears are harvested when they are golden and full to obtain rice grains.

[0056] Comparative Example 5

[0057] This comparative example provides a rice planting method, in which the antimony treatment concentration is set to 100 mg / kg, the amount of sepiolite applied is 0, recorded as H0, and the specific steps are consistent with those in Example 1. The rice ears are harvested when they are golden and full to obtain rice grains.

[0058] Comparative Example 6

[0059] This comparative example provides a rice planting method, in which the antimony treatment concentration is set to 200 mg / kg, the amount of sepiolite applied is 0, recorded as H0, and the specific steps are consistent with those in Example 1. The rice ears are harvested when they are golden and full to obtain rice grains.

[0060] Comparative Example 7

[0061] This comparative example provides a rice planting method, in which the antimony treatment concentration is set to 400 mg / kg, the amount of sepiolite applied is 0, recorded as H0, and the specific steps are consistent with those in Example 1. The rice ears are harvested when they are golden and full to obtain rice grains.

[0062] The rice and rice grains obtained in the above embodiments and comparative examples were sampled and tested after growing for 120 days to maturity. The test method is as follows:

[0063] Agronomic traits and biomass determination: The plant height, number of stalks, leaf area and main root length of rice were determined by conventional methods. The root volume was measured according to the Archimedean principle. Fresh samples of each organ were taken and fixed at 105°C for 0.5 h, then dried at 80°C to constant weight, and the dry weight of each part was measured using an electronic balance.

[0064] Yield indicators: The number of ears per pot, the number of grains per ear, the fruit setting rate, the thousand-grain weight, the yield per pot and other indicators were measured at maturity and weighed using an electronic balance (accuracy 0.001g).

[0065] Determination of photosynthetic indexes: The iFL portable photosynthetic fluorescence composite measurement system was used to measure the photosynthetic rate (A), evaporation rate (E), intercellular CO2 concentration (Ci) and stomatal conductance (Gs) of rice flag leaves between 9:00 and 11:00 a.m. on sunny days.

[0066] Chlorophyll determination: Use a SPAD portable chlorophyll fluorescence meter to select rice flag leaves, measure 2 sample leaves each, repeat the measurement 3 times for each leaf, take the average, and use the SPAD value to express the relative chlorophyll content.

[0067] Physiological index determination: Cut the tender roots at the bottom of rice, weigh 0.1g of fresh weight roots respectively, add 1mL of extract to treat the samples, ice bath homogenize, centrifuge at 8000g for 10min at 4℃, take the supernatant and place it on ice for testing various indicators. The malondialdehyde (MDA) content was determined by thiobarbituric acid (TBA) method, and the unit was nmol / g. The superoxide dismutase (SOD) activity was determined by the nitroblue tetrazolium method (NBT) at 560nm absorbance, and the unit was U / g; the peroxidase (POD) activity was determined by the guaiacol method through the change of absorbance at 470nm, and the unit was U / g; the catalase (CAT) activity was determined by the ammonium molybdate colorimetric method at 405nm absorbance, and the unit was U / g.

[0068] Determination of antimony content in seeds: pressure tank digestion method was used, referring to GB5009.268-2016 National Food Safety Standard Determination of Multiple Elements in Food.

[0069] The results of the effect of the sepiolite of the present invention on the agronomic traits of rice under antimony stress are shown in Table 1, the results of the effect of the sepiolite of the present invention on the yield traits of rice under antimony stress are shown in Table 2, and the results of the effect of the sepiolite of the present invention on the SPAD value and photosynthesis of rice leaves under antimony stress are shown in Table 3.

[0070] The effect of the present invention on the aboveground biomass of rice in soils contaminated with antimony at different concentrations is shown in Figure 1 The effect of the present invention on the underground biomass of rice in soils contaminated with antimony at different concentrations is shown in Figure 2 The effect of the present invention on the MDA content of rice roots in soils contaminated with antimony at different concentrations is shown in Figure 3 The effect of the present invention on the SOD content of rice roots in soils contaminated with antimony at different concentrations is shown in Figure 4 The effect of the present invention on the POD content of rice roots in soils contaminated with antimony at different concentrations is shown in Figure 5 The effect of the present invention on the CAT content of rice roots in soils contaminated with different concentrations of antimony is shown in Figure 6 The effect of the present invention on the antimony content of rice grains under different concentrations of antimony contaminated soil is shown in Figure 7 .

[0071] The analysis of the test results is as follows:

[0072] 1. Effect of the present invention on agronomic traits of rice

[0073] As shown in Table 1, when sepiolite was not added, the plant height, leaf area, root length and root volume of rice decreased with the increase of Sb concentration, while the number of tillers increased first and then decreased. In CK soil, with the increase of sepiolite application, the agronomic traits of rice were improved to varying degrees, and reached a significant difference level when the sepiolite application amount was H50. In soils treated with different concentrations of Sb, the application of sepiolite increased the plant height, tiller number, root length and root volume of rice to varying degrees. Except for the leaf area, which increased first and then decreased, the other agronomic traits increased with the increase of sepiolite, and the difference was significant when the sepiolite application amount was H50. Compared with no application of sepiolite, under Sb100 treatment, the application of different masses of sepiolite increased the plant height, tiller number, root length and root volume of rice by 1% to 7.1%, 1% to 12.6%, 1% to 2.1% and 4.4% to 14.7%, respectively; under Sb200 treatment, the above four traits increased by 1% to 5.6%, 5.2% to 30.2%, 1% to 22% and 23.6% to 33.5%, respectively; under Sb400 treatment, the above traits increased by 3.5% to 6.1%, 16.2% to 94.8%, 11.8% to 29% and 30.1% to 65.5%, respectively.

[0074]

[0075] 2. Impact of the present invention on rice biomass

[0076] Depend on Figure 1 and Figure 2It can be seen that when no sepiolite was added, the biomass of rice decreased with the increase of Sb treatment concentration. Compared with the control, the aboveground biomass decreased by 4.3% to 43.3%, and the underground biomass decreased by 8.2% to 40.2%. In CK soil, with the increase of sepiolite application, the aboveground biomass of rice increased to varying degrees, and reached a maximum of 201g when H10 was applied, an increase of 7.2% compared with the control. The underground biomass also increased to varying degrees, reaching a maximum of 23.6g when H50 was applied, an increase of 25.7% compared with the control. In soils with different Sb treatment concentrations, the application of sepiolite can increase the aboveground and underground biomass of rice. Except for the underground biomass under Sb100 treatment, which did not reach a significant difference, the rice biomass increased with the increase of sepiolite application under other Sb treatments, and reached a significant level when the sepiolite application amount was H30 and H50. Compared with the treatment without sepiolite, under the Sb100, Sb200 and Sb400 treatments, the application of H50 sepiolite increased the biomass of the aboveground part of rice to 201.8g, 192.6g and 173.3g, with an increase rate of 16.6%, 78.9% and 63%, and the biomass of the underground part increased to 18.1g, 19g and 18.5g, with an increase rate of 4.6%, 18.7% and 60.3%.

[0077] III. Effect of the present invention on rice yield traits

[0078] Table 2 shows that when no sepiolite was added, in soils contaminated with different concentrations of Sb, except for the number of grains per panicle, which was higher than the control and increased with the increase of Sb concentration, other yield traits were lower than the control and decreased with the increase of Sb concentration. In CK soil, with the increase of sepiolite application, the number of panicles per pot of rice showed an upward trend, the fruit setting rate, 1000-grain weight and yield per pot showed a downward trend, and the number of grains per panicle first increased and then decreased, and reached the maximum value when the sepiolite application amount was H30. Under the treatments of Sb100, Sb200 and Sb400, with the increase of sepiolite application, the number of panicles per pot of rice, the fruit setting rate, 1000-grain weight and yield per pot increased to varying degrees, and reached the maximum value when the sepiolite application amount was H50, with significant differences. Under the treatments of Sb100 and 200, the number of grains per panicle showed an upward trend first and then decreased with the increase of sepiolite application, and showed a downward trend under the treatment of Sb400. Compared with the treatment without application of sepiolite, under the Sb100 treatment, the application of different masses of sepiolite increased the number of rice ears per pot, fruit setting rate, 1000-grain weight and yield per pot by 15.6%-25.1%, 3.2%-7.3%, 0.5%-0.6% and 5.8%-11.8%, respectively, among which the increase of 1000-grain weight was not large; under the Sb200 treatment, the above indicators increased by 1%-33.5%, 3.1%-7.3%, 6.3%-7.5% and 14.7%-40.3%, respectively; under the Sb400 treatment, the above indicators increased by 28.7%-88%, 9.2%-16.3%, 5.9%-12.3% and 39.3%-64.7%, respectively.

[0079]

[0080] IV. Effects of the present invention on SPAD values ​​and photosynthesis of rice leaves under antimony stress 1. Effects of the present invention on SPAD values

[0081] As shown in Table 3, when no sepiolite was added, the SPAD value of rice decreased with the increase of Sb concentration. When different masses of sepiolite were applied in CK soil, the SPAD value of rice decreased to varying degrees compared with the control, and there were significant differences when the sepiolite application amount was H30 and H50. In the Sb100 treated soil, with the increase of the application amount of sepiolite, the SPAD value of rice showed a trend of first increasing and then decreasing. Compared with the treatment without sepiolite, the SPAD value of rice was significantly increased when the application amount of sepiolite was H10, with an increase of 5.1%, and it was significantly reduced when the application amount was H50, with a decrease of 7.4%; in Sb200 and 400 soils, with the increase of the application amount of sepiolite, the SPAD value of rice showed an upward trend, and there were significant differences when the application amount of sepiolite was H30 and H50, with the increase rates of 5.3% to 7.9% and 1.1% to 6.7%, respectively.

[0082] 2. The impact of the present invention on photosynthesis

[0083] Table 3 shows that when no sepiolite was added, the net photosynthetic rate (A), transpiration rate (E), intercellular CO2 concentration (Ci) and stomatal conductance (Gs) of rice leaves decreased with the increase of Sb treatment concentration. In CK soil, the application of different masses of sepiolite reduced the A, E, Ci and Gs of leaves to varying degrees. Compared with the treatment without sepiolite, in the soil treated with Sb100, with the increase of sepiolite application, the A, E, Ci and Gs of the leaves showed a trend of first increasing and then decreasing, among which the A, Ci and Gs of the leaves were lower than those of the control when the sepiolite application amount was H50; in the soil treated with Sb200, with the increase of sepiolite application, the A of the leaves showed an upward trend, while E, Ci and Gs showed a trend of first increasing and then decreasing, and reached the maximum value when the sepiolite application amount was H30, with significant difference; in the soil treated with Sb400, with the increase of sepiolite application, the A, E, Ci and Gs of the leaves showed an upward trend, and reached a significant difference level when the sepiolite application amount was H50, with the increase rates of 4%-20.8%, 6.8%-26.9%, 1%-5.1% and 7.6%-23%, respectively.

[0084]

[0085] V. Effect of the present invention on MDA content and antioxidant enzyme activity in rice roots under antimony stress 1. Effect of the present invention on MDA content

[0086] Depend on Figure 3 It can be seen that when no sepiolite was added, the MDA content of rice roots increased with the increase of Sb concentration, from 10nmol / g to 12.9nmol / g. In CK soil, with the increase of sepiolite application, the MDA content of the roots gradually decreased. When the sepiolite application amount was H50, the MDA content of the roots decreased significantly, from 10nmol / g to 7.6nmol / g. In the Sb100 and 200 soils, with the increase of the amount of sepiolite applied, the MDA content of the roots showed a downward trend. Compared with the treatment without sepiolite application, it was significantly reduced when the sepiolite application amount was 50g / kg, from 10.5nmol / g and 11.2nmol / g to 8.6nmol / g and 8.5nmol / g, respectively, with a decrease of 19% and 24.1%; in the Sb400 treated soil, with the increase of the amount of sepiolite applied, the MDA content of the roots showed a downward trend, reaching the minimum value when the sepiolite application amount was H50, decreasing from 12.9nmol / g to 11.6nmol / g, with a decrease of 10%, which did not reach the significant difference level.

[0087] 2. The influence of the present invention on the content of SOD

[0088] Depend on Figure 4 It can be seen that when no sepiolite was added, the SOD content of the rice root system showed a trend of first increasing, then decreasing, and then increasing with the increase of Sb concentration, from 56U / g to 164.7U / g and then decreasing to 66.3U / g. In CK soil, with the increase of sepiolite application, the SOD content of the root system first increased and then decreased, reaching the maximum value when the sepiolite application amount was H30, increasing from 56U / g to 205.7U / g, an increase of 267%, reaching a very significant difference level. In the soils treated with Sb100, 200 and 400, with the increase of the amount of sepiolite applied, the SOD content of the roots showed a trend of first increasing and then decreasing. Compared with the treatment without sepiolite application, they all increased to varying degrees, with increases of 5.6% to 22.9%, 53% to 167.7% and 10.9% to 121.6%, respectively. When the amount of sepiolite applied was H30, it reached the maximum value, which was 202.5U / g, 177.5U / g and 205.9U / g, respectively, with significant differences.

[0089] VI. Effect of the present invention on the activity of antioxidant enzymes POD and CAT

[0090] Depend on Figure 5 It can be seen that when no sepiolite was added, the POD content of rice roots increased with the increase of Sb concentration, from 7893.3U / g to 11786.7U / g. In CK soil, with the increase of sepiolite application, the POD content of the root system gradually increased, and reached a significant difference level when the sepiolite application amount was H50. Compared with the treatment without sepiolite application, in the Sb100 treated soil, the POD content of the root system showed an upward trend with the increase of sepiolite application, and reached a maximum value of 17337.7U / g when the sepiolite application concentration was H50, an increase of 76.6%, and the difference was significant; in the Sb200 treated soil, the POD content of the root system showed a trend of first increasing and then decreasing with the increase of sepiolite application, and there was a small increase when the sepiolite application amount was H10 and 30, which were 14 and 15 respectively. 391U / g and 11791U / g. When the application amount was H50, the POD content of the roots reached a minimum of 6120U / g, which was 92.1% lower than the control. In the soil treated with Sb400, the POD content of the roots first increased and then decreased with the increase of the application amount of sepiolite. Compared with the treatment without sepiolite application, it increased by 20.3% to 47.0%, and reached a maximum of 17333.3U / g when the application amount of sepiolite was H30, with significant difference.

[0091] Depend on Figure 6It can be seen that when no sepiolite was added, the CAT content of the root system increased with the increase of Sb concentration, which was similar to the POD value of rice roots, rising from 134.7U / g to 484U / g. In CK soil, with the increase of sepiolite application, the CAT content of the root system showed an upward trend, and when the sepiolite application amount was H30 and 50, it reached a very significant difference level, which was 279.8U / g and 283.7U / g, respectively. Compared with the treatment without sepiolite, in the soil treated with Sb100, the CAT content of the roots first increased and then decreased with the increase of the amount of sepiolite applied, and reached a maximum value of 351.7U / g when the sepiolite concentration was H30, with an increase of 32.5%, and the difference was significant; in the soil treated with Sb200, the CAT content of the roots first increased and then decreased with the increase of the amount of sepiolite applied, among which it increased significantly when the amount of sepiolite applied was H10, from 440.6U / g to 478.2U / g, and decreased significantly when the amount of sepiolite applied was H30 and 50, from 440.6 to 387.3U / g and 418.6U / g, respectively, which were 12% and 5% lower than the control; in the soil treated with Sb400, the CAT content of the roots decreased to varying degrees with the increase of the amount of sepiolite applied, with the maximum decrease of 3.2%.

[0092] VII. Effect of the present invention on antimony concentration in rice grains under antimony stress

[0093] Depend on Figure 7 It can be seen that when no sepiolite was added, the Sb content of rice grains increased to varying degrees with the increase of Sb concentration. In CK soil, the Sb content of grains increased with the increase of sepiolite application, from 0.015 mg / kg to 0.051 mg / kg, and reached a significant difference level when the sepiolite application amount was H30 and 50. In the soils treated with Sb100, 200 and 400, the Sb content of grains showed a downward trend with the increase of sepiolite application, and all reached the minimum value when the sepiolite application amount was H50. Compared with the treatment without sepiolite, in the soil treated with Sb100, the Sb content of the grain decreased from 0.106 mg / kg to 0.073 mg / kg, with a reduction rate of 31.1%, which was significant; in the soil treated with Sb200, the Sb content of the grain decreased from 0.072 mg / kg to 0.056 mg / kg, with a reduction rate of 22.2%, reaching an extremely significant difference level; in the soil treated with Sb400, the Sb content of the grain decreased from 0.110 mg / kg to 0.073 mg / kg, with a reduction rate of 33.6%, reaching an extremely significant difference level.

[0094] In summary, under different Sb stress treatments, compared with no application of sepiolite (H0), the application of different amounts of sepiolite (H10, H30 and H50) can improve rice agronomic traits and photosynthesis, alleviate root peroxidation damage, and reduce the Sb content of rice grains. The overall performance of each treatment is H0<H10<H30<H50, and the application of 50g / kg sepiolite has the best effect. The present invention provides a theoretical basis for further solving the Sb pollution of rice fields. In the future, the Sb content of brown rice can meet the national food safety standards by modifying and compounding sepiolite to ensure food production safety.

[0095] It should be clear that the various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. For the embodiments of the method, the relevant parts can refer to the partial description of the device embodiment (adopted according to the writing situation). In addition, for the sake of brevity, the detailed description of the known method technology is omitted here.

[0096] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A planting method for reducing the antimony content in rice grains, characterized in that: The invention discloses a rice planting method in pots when the planting soil is antimony-contaminated soil, comprising the steps of: first applying sepiolite to the planting soil in the planting pot, stirring evenly, and then transplanting the rice into the planting pot; during the rice planting, applying nutrients to the soil and keeping water on the soil surface; harvesting when the rice ears are golden and full, so as to obtain rice grains with low antimony content.

2. The planting method according to claim 1, characterized in that: The concentration of antimony in the antimony-contaminated soil is 100-400 mg / kg.

3. The planting method according to claim 1 or 2, characterized in that: The antimony in the antimony-contaminated soil is trivalent antimony.

4. The planting method according to claim 1, characterized in that: The planting pot has a size of 29 cm×20 cm and a height of 18 cm. Two rice plants are planted in each planting pot, and the spacing between the plants is 9 cm.

5. The planting method according to claim 1, characterized in that: The application amount of the sepiolite is 1% to 5% of the dry weight of the planting soil.

6. The planting method according to claim 1, characterized in that: Sepiolite is applied to the planting soil in the planting pot for 30 days or more, and then the rice is transplanted into the planting pot.

7. The planting method according to claim 1, characterized in that: The sepiolite is natural sepiolite with a mesh size of 200.

8. The planting method according to claim 1, characterized in that: The nutrients include at least one of nitrogen fertilizer, phosphorus fertilizer and potassium fertilizer.

9. The planting method according to claim 1, characterized in that: The depth of water accumulation on the soil surface is 2 to 3 cm.

10. The planting method according to any one of claims 1 to 9, characterized in that: The antimony content in the rice grains is 0.056-0.073 mg / kg.

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