Power supply device and method for establishing rice nano-silicon defense barrier before transplanting

Abstract

The present invention discloses an energized device and method for establishing a rice nano-silicon defense barrier before transplanting. When using the device, the rice roots can be immersed in an energized nutrient solution containing nano-silicon before transplanting, and a silicon barrier can be formed at the roots after 30 minutes. The present invention significantly improves the growth of rice under heavy metal stress and inhibits the absorption of heavy metals in the aboveground part. In a 5-day stress experiment, the effect of electrically stimulated nano-silicon polymerization was better than that of traditional matrix-applied nano-silicon. In addition, transcriptional analysis further revealed that the gene regulatory effect of electrically stimulated nano-silicon was significantly different from that of simple electrical stimulation. The present invention provides a convenient treatment method for improving the stress resistance of rice before transplanting.

Description

Technical Field

[0001] The present invention belongs to the field of agricultural pre-transplantation treatment, and more specifically, relates to a device and method for establishing an anti-heavy metal defense barrier for rice before transplanting by electrifying a solution containing nano-silicon. Background Art

[0002] Heavy metal pollution in soil caused by industrial emissions, agricultural fertilization, and urban waste has become an increasingly serious environmental problem worldwide. The accumulation of chromium, lead, cadmium, mercury, arsenic, etc. in the soil can lead to a decline in soil quality and damage to the ecosystem. With the exception of a few hyperaccumulators, most plants do not require heavy metals themselves and therefore have not evolved corresponding transport proteins. Heavy metals enter plants mainly through the apoplast pathway, and a few enter through shared transport proteins due to their similar properties to other essential elements. Heavy metals in crops not only affect plant growth, development, and yield, but also pose a threat to human health through the food chain. Therefore, it is particularly important to block heavy metals in the roots and prevent them from entering the edible above-ground parts of plants to ensure food security.

[0003] Rice cultivation requires transplanting. Compared to plants at other stages after transplanting, rice seedlings have the lowest stress resistance. Furthermore, the flooded environment of rice fields increases the bioavailability of many heavy metals. Developing methods to help rice roots quickly establish a silicon defense barrier before transplanting would not only aid the growth and stress resistance of the seedlings but also lay a good foundation for subsequent growth.

[0004] Silicon has been shown to enhance plant resistance to heavy metal stress. Silicon reduces heavy metal absorption by forming a physical barrier and enhances plant antioxidant capacity by increasing antioxidant enzyme activity and promoting the synthesis of secondary metabolites. Silicon can also improve water and nutrient absorption in plants. In recent years, nano-silicon has shown promise in enhancing plant stress resistance in agriculture due to its smaller particle size, greater surface area, and improved absorption compared to traditional fertilizers. However, nano-silicon fertilizers are currently primarily applied to the soil and foliage. Effective methods for using nano-silicon to establish a heavy metal defense barrier in rice plants before transplanting are still lacking. Summary of the Invention

[0005] The purpose of the present invention is to quickly establish a nano-silicon defense barrier for rice and evaluate the role of the barrier in plant resistance to heavy metal stress.

[0006] The technical solutions specifically adopted in the present invention are as follows:

[0007] In a first aspect, the present invention provides an energizing device for establishing a rice nano-silicon defense barrier before transplanting, comprising a power supply device and a lidless container made of a non-conductive material;

[0008] The uncovered container is divided into three interconnected chambers by two perforated partitions. The plant chamber for placing rice seedlings is located between the two perforated partitions, and two power supply chambers are located on both sides of the plant chamber. The entire uncovered container stores a nutrient solution containing nano-silicon, and the height of the nutrient solution should be sufficient to immerse the roots of the rice seedlings.

[0009] The power supply device includes a battery and positive and negative electrode plates connected to the positive and negative poles of the battery respectively. The positive electrode plate and the negative electrode plate are respectively arranged below the nutrient solution level in two power-on chambers, and are used to apply a voltage to both sides of the roots of rice seedlings immersed in the nutrient solution to induce the roots to form a nano-silicon barrier.

[0010] As a preferred embodiment of the first aspect, both the positive electrode plate and the negative electrode plate are made of nickel sheets.

[0011] As a preferred embodiment of the first aspect, in the power supply device, the positive and negative electrodes of the battery are connected to two metal clips via wires, and the positive electrode plate and the negative electrode plate are conductively clamped and fixed by the metal clips.

[0012] As a preferred embodiment of the first aspect, the battery is a storage battery with a supply voltage of 8 to 12V.

[0013] As a preferred embodiment of the first aspect, the coverless container is a coverless acrylic plastic box.

[0014] As a preferred embodiment of the first aspect, the nutrient solution is 1 / 4 Kimura B nutrient solution.

[0015] As a preferred embodiment of the first aspect, the concentration of nano-silicon in the nutrient solution is 8-12 mM, and the particle size of nano-silicon is 25-35 nm.

[0016] In a second aspect, the present invention provides a method for establishing a rice nano-silicon defense barrier in front of the rice seedlings using the power-on device described in any of the schemes of the first aspect above, characterized in that the rice seedlings to be planted are placed in the plant chamber with their leaves facing upward and their roots facing downward, and their roots are kept immersed in a nutrient solution containing nano-silicon; then the power supply device is used to apply a voltage of 8 to 12 V to both sides of the roots of the rice seedlings immersed in the nutrient solution for electrical stimulation, and after the nano-silicon defense barrier is formed at the roots for at least 30 minutes, the rice seedlings are taken out.

[0017] As a preference of the second aspect above, the voltage of the electrical stimulation is preferably 12V.

[0018] As a preference of the second aspect above, the electrical stimulation is preferably maintained for 30 minutes.

[0019] In a third aspect, the present invention provides a method for growing rice in heavy metal contaminated soil, which comprises: electrically stimulating the rice seedlings to be planted according to the method described in the second aspect above, and then transplanting them into heavy metal contaminated soil after forming a nano-silicon defense barrier at the roots to enhance the rice's ability to resist heavy metal stress.

[0020] Compared with the prior art, the present invention has the following beneficial effects: currently, nano-silicon is mainly supplied to plants through leaf spraying or matrix application, but much of the nano-silicon applied to the soil is fixed by the soil and is not absorbed by the plants. In addition, the process of nano-silicon in the soil being deposited in the roots to form a defense barrier is relatively slow, while silicon sprayed from leaves is difficult to be transported to the root system to help the roots establish a defense barrier. The present invention can quickly induce the roots to form a nano-silicon defense barrier within half an hour. Secondly, although nano-silicon can help plants improve their stress resistance, there are also hidden dangers in terms of biosafety and ecological risks. The present invention only requires adding nano-silicon to the device and does not require large-scale application to the environment, which not only improves the fertilizer efficiency but also reduces pollution and potential ecological risks. In addition, matrix application of silicon requires a large amount of manpower and material resources, while the device of the present invention is light, easy to operate, requires little manpower investment, and has safe voltage, which is conducive to promotion to farmers. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the structure of the device for inducing the establishment of a nano-silicon defense barrier for rice roots by electrical induction in the present invention;

[0022] Figure 2 This is a diagram showing the effect of the root nano-silicon defense barrier established by powering on in an embodiment of the present invention;

[0023] Figure 3 The effect of establishing a root nano-silicon defense barrier by electrification on the hexavalent chromium stress resistance of rice in the embodiment of the present invention; a is the plant height under different treatments, and b is the chromium concentration in the aboveground part under different treatments;

[0024] Figure 4 This is a comparison of the effects of the electrical induction to form a nano-silicon defense barrier and the substrate application of nano-silicon in an embodiment of the present invention; a is the plant height under different treatments, and b is the chromium concentration in the aboveground part under different treatments;

[0025] Figure 5 The main gene enrichment pathway for the formation of nano-silicon defense barrier induced by electrical stimulation compared with normal rice and pure electrical stimulation rice. DETAILED DESCRIPTION

[0026] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below. The technical features in the various embodiments of the present invention can be combined accordingly without conflicting with each other.

[0027] In the description of the present invention, it should be understood that when an element is considered to be "connected" to another element, it can be directly connected to the other element or indirectly connected, that is, there are intermediate elements. On the contrary, when an element is said to be "directly" connected to another element, there are no intermediate elements.

[0028] like Figure 1 As shown, in an embodiment of the present invention, an energizing device for establishing a rice nano-silicon defense barrier before transplanting is provided. The device includes two main components, namely a power supply device 1 and a lidless container made of non-conductive material. The lidless container is a watertight container made of non-conductive material, and the specific material is not limited. In this embodiment, the lidless container is a lidless rectangular plastic box made of acrylic material, with a thickness of 0.2 mm, and a length, width and height of 20 cm, 10 cm and 8 cm respectively. In addition, the lidless container is divided into three interconnected chambers by two perforated partitions. The plant chamber 3 for placing rice seedlings is located between the two perforated partitions, and two energizing chambers 2 are located on both sides of the plant chamber 3. In this embodiment, a rectangular PP plastic plate with circular holes can be inserted into the rectangular plastic box at 5 cm and 15 cm in the length direction. The length of the rectangular PP plastic plate is 10 cm and the width is 8 cm. The plant chamber 3 is located between the two plastic panels. Because the PP panels are evenly perforated with a series of circular holes, nutrient solution can flow freely between the plant chamber 3 and the power supply chambers 2 on either side. The entire uncovered container stores a nutrient solution containing nanosilicon, and the height of the nutrient solution should be high enough to submerge the roots of the rice seedlings. The specific height should be adjusted based on the specific rice seedlings being treated. The plant chamber 3 provides temporary storage for rice seedlings. In actual use, rice seedlings can be placed in bundles within the plant chamber 3, keeping their roots submerged in the nutrient solution. No external fixtures are required, making it easy to carry and use.

[0029] In addition, the formula of the nutrient solution stored in the above-mentioned uncovered container should meet the growth requirements of rice, but the specific ingredients can be configured according to actual needs. In an embodiment of the present invention, the nutrient solution can use 1 / 4 Kimura B nutrient solution. In addition, the nutrient solution should also be added with nano-silicon required to establish a nano-silicon barrier for the root system. The concentration of nano-silicon in the nutrient solution is preferably 8-12mM, more preferably 10mM, and the nano-silicon particle size is preferably 25-35nm, more preferably 30nm.

[0030] The power supply device 1 includes a battery and positive and negative electrode plates connected to the positive and negative poles of the battery respectively. The positive electrode plate and the negative electrode plate are respectively arranged below the level of the nutrient solution in the two power-on chambers 2, and are used to apply a voltage to both sides of the roots of the rice seedlings immersed in the nutrient solution to induce the roots to form a nano-silicon barrier.

[0031] In the power supply device 1 of this embodiment, both the positive electrode plate and the negative electrode plate are made of nickel sheets. The positive and negative poles of the power supply are connected to two metal clips through wires, and the positive electrode plate and the negative electrode plate are respectively fixed by the metal clips for conductive clamping. The introduction of the metal clip is to facilitate the replacement and fixation of the nickel sheet. In theory, it is also feasible to directly connect the wire to the metal clip. The power supply device 1 can be powered by a portable battery as a power source, and its output voltage is generally controlled at 8 to 12V, preferably 12V (reference standard GB / T8897.2). In this embodiment, the power supply device 1 connects the current output by the power supply to the power supply chamber 2 through two wires with metal alligator clips. Two nickel sheets are clamped on the alligator clips to expand the contact area. The electrical stimulation applied to the rice root system will accelerate the deposition of nano-silicon in the nutrient solution on the root surface to form a nano-silicon barrier.

[0032] Therefore, the present invention is based on the above Figure 1 The device shown further provides a method for establishing a nano-silicon defense barrier for rice seedlings before they are planted. The method involves placing rice seedlings to be planted in the plant chamber 3 with their leaves facing upward and their roots facing downward, with their roots submerged in a nutrient solution containing nano-silicon. The power supply device 1 then applies an 8-12V voltage to both sides of the rice seedlings' roots, which are immersed in the nutrient solution. This voltage is maintained for at least 30 minutes until the nano-silicon defense barrier forms on the roots, and the rice seedlings are removed. At this point, the rice seedlings' roots have formed a nano-silicon barrier, which helps maintain normal growth under heavy metal stress, increases fresh weight, and reduces heavy metal concentrations in the aboveground areas.

[0033] In the above method, the voltage of electrical stimulation is preferably 12V, and the duration of electrical stimulation is preferably 30 minutes.

[0034] Therefore, the above-mentioned power supply device is portable. When planting rice in heavy metal contaminated soil, the rice seedlings can be treated directly at the planting site. That is, the rice seedlings to be planted are first electrically stimulated according to the above-mentioned method, and then transplanted into heavy metal contaminated soil after a nano-silicon defense barrier is formed at the roots, so as to enhance the rice's ability to resist heavy metal stress.

[0035] The specific implementation and technical effects of the above-mentioned energizing device for electrically stimulating and inducing the formation of a root nano-silicon defense barrier before transplanting are described in detail below through several embodiments.

[0036] Example 1

[0037] In this embodiment, the above Figure 1 The energized device shown builds a nano-silicon defense barrier on the root system and detects the formed silicon barrier.

[0038] Rice seeds (Oryza sativa L. cv. Nipponbare) were sterilized with 10% hydrogen peroxide for 10 minutes, washed three times with deionized water, and placed on damp filter paper. They were germinated in the dark at 30°C for five days. The rice seedlings were then transferred to a 1 / 4 concentration of Kimura B nutrient solution (pH adjusted to 6), which was changed every seven days. The temperature in the artificial climate chamber was 30°C, the humidity was 55%, and the light and dark periods were 14 and 10 hours, respectively. Fourteen-day-old rice seedlings were used for the electrical stimulation experiment.

[0039] In this example, three treatments were set up, with different nutrient solution compositions and electrical stimulation methods within the uncovered containers. Specifically, the control group (CK) immersed the rice roots in a 1 / 4 concentration Kimura B nutrient solution for 30 minutes; the silicon-treated group (NanoSi) immersed the rice roots in a 1 / 4 concentration Kimura B nutrient solution containing 10mM nanosilicon (particle size 30nm) without electricity for 30 minutes; and the electrical-treated group (ENanoSi) immersed the rice roots in a 1 / 4 concentration Kimura B nutrient solution containing 10mM nanosilicon, with electricity applied to the nutrient solution for 30 minutes (i.e., a 12V voltage was applied between the positive and negative electrodes in the electrification chamber 2). The root surface was then cleaned with a 10% EDTA solution and deionized water. After each group completed the 30-minute treatment, fresh root segments of a portion of the seedlings were excised, immediately attached to carbon glue, and freeze-dried in a freeze dryer. Prior to testing, the roots were sprayed with gold. Silicon deposition on the root surfaces of rice plants subjected to different treatments was observed using SEM-EDS and photographed. Another portion of the roots was dried and then digested with HNO₃, H₂O₂, and HF. The volume was adjusted to 20 ml with 4% boric acid (to remove residual HF), and Si concentration was determined using ICP-OES. Three biological replicates were included for each treatment.

[0040] The results of SEM showed that the surface of rice roots not soaked in nano-silicon was very smooth, with no obvious silicon particle deposition ( Figure 2 However, a large amount of nano-silicon was deposited on the surface of rice roots after being electrified in nano-silicon for 30 minutes, which was much more than that of rice roots that were immersed in nano-silicon for 30 minutes ( Figure 2 b and c). The roots of each treatment were digested and measured by ICP-OES. It was found that the root silicon concentration of the NanoSi group was 8.6 times that of the CK group, and the root silicon concentration of the ENanoSi group was 2.1 times that of the NanoSi group ( Figure 2 (d) This indicates that the method used in this study can quickly establish a nano-silicon barrier in the rice root system.

[0041] Example 2

[0042] Example 1 has demonstrated the effectiveness of this method in rapidly establishing a nano-silicon barrier in the root system, but the impact of this method on the stress resistance of rice has not yet been evaluated. Chromium (Cr) is an important industrial mineral resource. However, it is a toxic and mutagenic environmental heavy metal pollutant and is listed as one of the top carcinogens by the International Agency for Research on Cancer. In this example, hexavalent chromium stress was used as an example to verify the effectiveness of the nano-silicon barrier established by the root system induced by electricity in resisting heavy metal stress.

[0043] Rice was still selected as the plant material, and the seed germination and seedling growth conditions were the same as in Example 1. Three treatments were set up: CK group: 14-day-old rice that had not been treated in advance was planted in a nutrient solution that did not contain chromium; Cr group: rice that had not been treated in advance was planted in a 1 / 4 Kimura B nutrient solution containing 50 μM hexavalent chromium (prepared with potassium dichromate, calculated as chromium); Cr+ENanoSi (i.e., a method of electrical stimulation using the energizing device of the present invention): 12V voltage was applied between the positive electrode plate and the negative electrode plate in the energizing chamber 2, and the rice was soaked in the energized nutrient solution containing 10 mM nano-silicon for 30 minutes, and then planted in a 1 / 4 Kimura B nutrient solution containing 50 μM hexavalent chromium. Three pots were used for each treatment, and four rice plants were planted in each pot. One plant was randomly selected from each pot during the measurement, with a total of three replicates.

[0044] After 5 days, the plant height of each rice group was measured. The aboveground rice was digested with HNO3, H2O2, and HF. The volume was adjusted to 20 ml with 4% boric acid (to remove residual HF), and the Cr concentration was determined by ICP-OES.

[0045] The results showed that hexavalent chromium stress inhibited the normal growth of rice, while Cr+ENanoSi improved the growth of rice under hexavalent chromium stress, with the plant height being 30% higher than that of the Cr group ( Figure 3 In a), the chromium concentration in the aboveground part decreased by 70% ( Figure 3 b). This indicates that the method of the present invention can improve the resistance of rice to hexavalent chromium stress.

[0046] Example 3

[0047] In this example, hexavalent chromium stress is taken as an example to compare the effects of the method of the present invention and the traditional matrix application of nano-silicon in enhancing the resistance of rice to heavy metal stress.

[0048] Rice was still selected as the plant material, and the seed germination and seedling growth conditions were the same as in Example 1. Two treatments were set up: Cr+NanoSi group (simulating the application of nano-silicon to the matrix), in which the rice that had not been treated in advance was planted in a 1 / 4 Kimura B nutrient solution containing 50μM hexavalent chromium, and nano-silicon at a concentration of 1mM was added (this concentration has been proven to be the best for promoting rice growth and stress resistance); Cr+ENanoSi group (i.e., a method of electrical stimulation using the energizing device of the present invention): a 12V voltage was applied between the positive electrode plate and the negative electrode plate in the energizing chamber 2, and the rice was soaked in the energized nutrient solution containing 10mM nano-silicon for 30 minutes, and then planted in a 1 / 4 Kimura B nutrient solution containing 50μM hexavalent chromium. Three pots were used for each treatment, and four rice plants were planted in each pot. One plant was randomly selected from each pot during the measurement, with a total of three replicates.

[0049] After 5 days, the plant height of each rice group was measured. The aboveground rice was digested with HNO3, H2O2, and HF. The volume was adjusted to 20 ml with 4% boric acid (to remove residual HF), and the Cr concentration was determined by ICP-OES.

[0050] The results showed that the rice growth condition of Cr+ENanoSi group was better than that of Cr+NanoSi group, and the plant height was 8% higher than that of Cr+NanoSi group ( Figure 4 In a), the chromium concentration in the aboveground part was 48% lower than that in the Cr+NanoSi group ( Figure 4 b). This indicates that the method of the present invention outperforms the traditional matrix-applied nano-silicon in a 5-day hexavalent chromium stress experiment.

[0051] Example 4

[0052] In this example, the effect of rapid establishment of rice root nano-silicon barrier by electrification on rice gene expression will be investigated, and the different effects of simple electrification and electrified nano-silicon will be distinguished.

[0053] Rice was still selected as the plant material, and the seed germination and seedling growth conditions were the same as in Example 1. Three treatments were set up, namely: CK group: normal 14-day-old rice was soaked in a non-electric device for 30 minutes; E group: 14-day-old rice was electrified in a nutrient solution for 30 minutes; ENanoSi group (i.e., a method of electrical stimulation using the electrification device of the present invention): 12V voltage was applied between the positive electrode plate and the negative electrode plate in the electrification chamber 2, and 14-day-old rice was electrified in a nutrient solution containing 10mM nano-silicon for 30 minutes. Four seedlings were used as a group, and each treatment contained 3 groups. The buds of the seedlings were cut off, quickly frozen in liquid nitrogen, and stored at -80°C for transcriptome analysis. Total RNA from each sample was extracted using an RNA extraction kit, and the concentration and integrity of the RNA were detected by Agilent 2100 Bioanalyzer (California, USA) and Qubit 2.0 fluorometer (Massachusetts, USA). Subsequently, the mRNA obtained from the sample was synthesized into double-stranded cDNA by reverse transcription. After the double-stranded cDNA was processed and purified, the cDNA library was enriched by PCR. After testing the library quality, sequencing was performed using the Illumina Novasek 6000 system platform. The sequencing data was then filtered using fastp software version 0.19.3 to obtain clean reads. FPKM (fragments per kilobase of transcript per million map fragments) was used to measure transcript or gene expression levels. DESeq2 was used to identify differentially expressed genes (|log2 fold change| ≥ 2, p < 0.05). A Venn diagram was used to display the common and unique differentially expressed genes between E and ENanoSi. The KEGG database was used to annotate gene pathways, and pathways with significant differences were displayed (p < 0.05).

[0054] The results showed that ENanoSi and E affected 363 genes together, E affected 733 genes alone, and ENanoSi affected 567 genes alone ( Figure 5 (a) This indicates that the phenomenon of rice gene expression regulation by nanosilicon treatment is not only caused by electricity but also by nanosilicon. Compared with E nanoSi, the KEGG enriched pathways with significant differences are mainly concentrated in benzoxazine biosynthesis, circadian rhythm, plant-pathogen interaction, motor protein, glycosylphosphatidylinositol protein synthesis, and α-linolenic acid metabolism ( Figure 5 This further demonstrates that nano-silicon has a strong regulatory effect on rice growth and stress resistance.

[0055] The embodiments described above are merely some preferred embodiments of the present invention and are not intended to limit the present invention. Persons skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, any technical solution obtained by equivalent substitution or equivalent transformation falls within the scope of protection of the present invention.

Claims

1. An energizing device for establishing a rice nano-silicon defense barrier before transplanting, characterized in that: It comprises a power supply device (1) and a lidless container made of a non-conductive material; The lidless container is divided into three interconnected chambers by two perforated partitions. The plant chamber (3) for placing rice seedlings is located between the two perforated partitions. Two power supply chambers (2) are located on both sides of the plant chamber (3). A nutrient solution containing nano-silicon is stored inside the entire lidless container, and the height of the nutrient solution should be able to immerse the roots of the rice seedlings. The power supply device (1) comprises a battery and positive and negative electrode plates connected to the positive and negative electrodes of the battery respectively. The positive electrode plate and the negative electrode plate are respectively arranged below the surface of the nutrient solution in the two power supply chambers (2) and are used to apply a voltage to both sides of the root system of the rice seedling immersed in the nutrient solution to induce the roots to form a nano-silicon barrier.

2. The energizing device for establishing a rice nano-silicon defense barrier before transplanting as claimed in claim 1, characterized in that: The positive electrode plate and the negative electrode plate are both made of nickel sheets.

3. The energizing device for establishing a rice nano-silicon defense barrier before transplanting as claimed in claim 1, characterized in that: In the power supply device (1), the positive and negative electrodes of the battery are connected to two metal clips via wires, and the positive electrode plate and the negative electrode plate are conductively clamped and fixed by the metal clips.

4. The energizing device for establishing a rice nano-silicon defense barrier before transplanting as claimed in claim 1, characterized in that: The battery is a storage battery with a supply voltage of 8 to 12V.

5. The energizing device for establishing a rice nano-silicon defense barrier before transplanting as claimed in claim 1, characterized in that: The coverless container is a coverless acrylic plastic box.

6. The energizing device for establishing a rice nano-silicon defense barrier before transplanting as claimed in claim 1, characterized in that: The nutrient solution is 1 / 4 Kimura B nutrient solution.

7. The energizing device for establishing a rice nano-silicon defense barrier before transplanting as claimed in claim 1, characterized in that: The nano-silicon concentration in the nutrient solution is 8-12 mM, and the nano-silicon particle size is 25-35 nm.

8. A method for establishing a rice nano-silicon defense barrier in front of rice seedlings using the energizing device according to any one of claims 1 to 7, characterized in that: The rice seedlings to be planted are placed in the plant chamber (3) with their leaves facing upward and their roots facing downward, and their roots are kept immersed in the nutrient solution containing nano-silicon. Then, the power supply device (1) is used to apply a voltage of 8 to 12 V to both sides of the roots of the rice seedlings immersed in the nutrient solution for electrical stimulation. After the voltage is maintained for at least 30 minutes to form a nano-silicon defense barrier on the roots, the rice seedlings are removed.

9. The method for establishing a rice nano-silicon defense barrier before seedling emergence according to claim 8, wherein: The voltage of the electrical stimulation was 12 V, and the duration of the electrical stimulation was 30 min.

10. A method for growing rice in heavy metal contaminated soil, characterized in that: The rice seedlings to be planted are electrically stimulated according to the method as claimed in claim 8, and then transplanted into heavy metal contaminated soil after a nano-silicon defense barrier is formed on the roots, so as to enhance the rice's ability to resist heavy metal stress.

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