A method for planting super-long grain rice

Abstract

This invention discloses a method for cultivating ultra-long grain rice, belonging to the field of agricultural planting technology. The method includes: selecting ultra-long grain rice seeds with a plant height ≥150cm and a single panicle grain length ≥8.5mm, and transplanting them after seedling cultivation; preparing aminated cellulose nanocrystals with an average particle size of 50-200nm; loading uniconazole and brassinolide onto the aminated cellulose nanocrystals to obtain supported nanocellulose, with uniconazole loading at 5-15wt% and brassinolide loading at 0.01-0.05wt%; dispersing the supported nanocellulose and polyglutamic acid in water, adjusting the pH to 4.5-5.5, and preparing a spray solution with a supported nanocellulose concentration of 0.5-2g / L and a polyglutamic acid concentration of 50-200mg / L; and using a drone to spray the foliage when the 2nd-3rd internode at the base of the ultra-long grain rice plant reaches a length of 1-2cm, with the drone flying at a height of 1.5-2.5m and a spraying flow rate of 1.5-2.5L / mu. By using nano-loading technology and polyglutamic acid compound, the growth control effect is extended to 15-20 days, reducing the number of sprayings, reducing plant height to 140-160cm, effectively enhancing lodging resistance, and making it suitable for local operations in Guizhou.

Description

Technical Field

[0001] This invention relates to the field of agricultural planting technology, specifically a method for planting ultra-long grain rice. Background Technology

[0002] Super-long grain rice (also known as giant rice) refers to a new rice germplasm with a plant height of ≥150cm and a single panicle grain length of ≥8.5mm. In 2006, Researcher Xia Xinjie of the Institute of Subtropical Agriculture Ecology, Chinese Academy of Sciences, first proposed a new direction for rice breeding: "super-tall stalks and super-large biomass". After more than ten years of research, he successfully bred super-high-yield and high-quality giant rice with a plant height of 2.0-2.2m and a single-season yield of more than 800kg per mu. This research achievement was selected as one of the "Top Ten Scientific and Technological Advances in China in 2017".

[0003] Guizhou, a major rice-producing region in China, has achieved significant breakthroughs in rice breeding and cultivation technologies in recent years. In 2025, the "Luyou 330" rice variety bred by the Guizhou Provincial Rice Research Institute achieved a yield of 854 kg per mu (approximately 16.7 kg per hectare) in a 100-mu (approximately 6.7 hectares) demonstration plot in Maling Street, Xingyi City. In the same year, the super rice "Ningxiangjing 9" bred by Academician Wan Jianmin's team at Nanjing Agricultural University achieved a yield of 833.63 kg per mu (approximately 5.25 kg per hectare) in a demonstration field in Wanfenglin, Xingyi City. This variety has been listed as a key variety for promotion and cultivation in Guizhou Province. Guizhou's rice industry is rapidly developing towards high yield, high quality, and mechanization.

[0004] However, the large-scale promotion and planting of extra-long grain rice in Guizhou faces two major bottlenecks: Firstly, Guizhou is a typical karst plateau mountainous region with complex terrain and concentrated rainfall during the flood season. According to data from the Guizhou Provincial Department of Agriculture and Rural Affairs, Guizhou experienced continuous heavy rainfall in June 2025, with some townships receiving over 400 mm of accumulated rainfall. Many rice paddies suffered from flooding, resulting in lodging of rice plants. Extra-long grain rice plants are more than 50% taller than conventional rice, significantly increasing the risk of lodging under severe weather conditions such as heavy rain and strong winds, severely impacting yield and quality.

[0005] Existing lodging prevention measures mainly include agronomical measures such as sun-drying the field to control nitrogen and increasing the application of silicon and potassium fertilizers, as well as chemical regulation measures such as spraying plant growth regulators such as paclobutrazol and uniconazole. For example, the China National Rice Research Institute has disclosed a seed soaking agent (CN104068027B) for cultivating rice seedlings with multiple tillers. This seed soaking agent contains uniconazole, brassinolide, and S-inducer, and can make seedlings short, sturdy, and multi-tillered with well-developed root systems through seed soaking. However, this technology uses a seed soaking method and can only play a role in the seedling stage. It cannot control the plant height growth after the jointing stage of rice, and it is not specifically designed for the long-grain rice variety. The "Giant God® Rain" growth control and lodging prevention package launched by Singapore's New South Ocean Company combines amino acids, fish protein, chitosan oligosaccharide, and chlormequat chloride for controlling rice growth, but it also has problems such as short effective period (generally 5-7 days), need for multiple sprays, and low utilization rate.

[0006] Furthermore, the excessive height of extra-long grain rice plants makes it difficult for manual application of growth regulators to reach the upper and middle parts of the plant, and drone spraying results in long sedimentation paths and significant drift of the pesticide solution. Currently, agricultural drones are widely used in rice pest and disease control in Guizhou Province, and the technical guidelines issued by the Guizhou Provincial Plant Protection and Quarantine Station explicitly recommend using drones for aerial spraying. However, application parameters specifically for extra-long grain rice are still lacking.

[0007] In summary, the existing technology lacks a planting method that can effectively control the plant height of ultra-long grain rice, enhance lodging resistance, adapt to mechanized operations in mountainous areas of Guizhou, extend the duration of growth control, and reduce the number of spraying applications. Summary of the Invention

[0008] The purpose of this invention is to overcome the aforementioned technical difficulties and provide a method for planting ultra-long grain rice that is adapted to mechanized operations in mountainous areas of Guizhou, extends the duration of growth control, and reduces the number of spraying applications.

[0009] To achieve the above objectives, the technical solution adopted is as follows: A method for cultivating ultra-long grain rice includes the following steps: (1) Select extra-long grain rice seeds with a plant height ≥150cm and a single panicle grain length ≥8.5mm, and transplant them to paddy fields after raising seedlings; (2) Prepare aminated cellulose nanocrystals, wherein the average particle size of the aminated cellulose nanocrystals is 50-200 nm; (3) Uniconazole and brassinolide were loaded onto aminated cellulose nanocrystals to obtain supported nanocellulose; the loading amount of uniconazole was 5-15 wt%, and the loading amount of brassinolide was 0.01-0.05 wt%. (4) Disperse the supported nanocellulose and polyglutamic acid in water, adjust the pH to 4.5-5.5, and prepare a spray solution; the mass concentration of the supported nanocellulose in the spray solution is 0.5-2 g / L, and the mass concentration of polyglutamic acid is 50-200 mg / L; (5) When the length of the second-third internode at the base of the ultra-long grain rice plant reaches 1-2 cm, a drone is used for foliar spraying. The drone flies at a height of 1.5-2.5 m and sprays at a flow rate of 1.5-2.5 L / mu.

[0010] Furthermore, in step (2), the preparation method of the amination cellulose nanocrystals is as follows: disperse cellulose nanocrystals in water, add polyethyleneimine or ethylenediamine, stir and react at 50-70℃ for 4-8 hours, centrifuge, wash, and dry.

[0011] Furthermore, in step (3), the loading method is as follows: dissolve uniconazole and brassinolide in ethanol, add them to the aminated cellulose nanocrystal suspension, stir for 12-24 hours, centrifuge, and dry.

[0012] Furthermore, the weight-average molecular weight of the polyglutamic acid is 500,000 to 2,000,000 Daltons.

[0013] Furthermore, in step (4), the polyglutamic acid is replaced with sodium alginate oligosaccharide at a concentration of 50-200 mg / L.

[0014] Furthermore, after the spraying in step (5), a second spraying is performed at an interval of 7-10 days, and the mass concentration of the supported nanocellulose in the spraying solution during the second spraying is 0.2-0.5 g / L.

[0015] Furthermore, the surface of the aminated cellulose nanocrystals contains amino groups, and its zeta potential is +20mV to +40mV.

[0016] Furthermore, in step (4), the spray solution also contains potassium silicate at a concentration of 100-200 mg / L.

[0017] The beneficial effects of the above-mentioned method are as follows: After applying this method for planting ultra-long grain rice, for varieties with plant height ≥150cm and single panicle grain length ≥8.5mm, precise application of pesticides is carried out at the jointing stage (when the length of the 2nd-3rd internode at the base of the plant reaches 1-2cm). This period is a critical window for internode elongation in rice; spraying growth regulators at this time can effectively shorten the length of basal internodes and reduce plant height. After treatment with the method of this invention, the plant height of ultra-long grain rice can be reduced to 140-160cm, significantly enhancing lodging resistance. In contrast, existing technologies (such as CN104068027B) use seed soaking methods, which can only play a role in the seedling stage and cannot control plant height growth after the jointing stage.

[0018] Aminated cellulose nanocrystals are used as the carrier for the growth regulator, with uniconazole and brassinolide loaded onto the nanocrystals. After spraying, the positively charged aminated cellulose nanocrystals (zeta potential +20mV to +40mV) combine with the negatively charged rice leaf surface through electrostatic interaction, forming a slow-release system. Compared with conventional spraying, the growth regulator effect of this invention is extended to 15-20 days, requiring only 1-2 sprays throughout the entire growth cycle (the concentration of the loaded nanocrystals is reduced to 0.2-0.5g / L during the second spray), reducing the number of sprays by 33-50% compared to conventional growth regulators (which require 2-3 sprays), thus reducing labor and operating costs.

[0019] Polyglutamic acid (Polyglutamic acid) is used in combination with supported nanocellulose. Polyglutamic acid is a natural high-molecular-weight polypeptide with strong water retention and absorption-promoting functions. On the one hand, Polyglutamic acid can alleviate the transpiration stress caused by the tall stems of ultra-long grain rice; on the other hand, Polyglutamic acid can promote the absorption of elements such as silicon and potassium by rice and enhance the mechanical strength of the stems. Polyglutamic acid and uniconazole form a synergistic effect of "controlling excessive growth + strengthening stems", which reduces plant height while ensuring stem fullness and avoids yield reduction caused by excessive growth control.

[0020] Foliar spraying is performed using drones, with a flight altitude of 1.5-2.5m and a spraying flow rate of 1.5-2.5L / mu. These parameters are specifically designed for the characteristics of ultra-long grain rice plants with a height ≥150cm, solving the problems of manual spraying's difficulty in reaching the upper and middle parts of the plant and the long sedimentation path of the sprayed pesticide by drones. In recent years, Guizhou has vigorously promoted the full mechanization of rice cultivation. Longli County has established three mechanized seedling raising demonstration sites, and Xiniu Village in Qingzhen City has achieved integrated "plowing, planting, management, and harvesting" services. The drone spraying technology of this invention can be seamlessly integrated into the existing mechanized service system and is suitable for the operating conditions of mountainous agriculture in Guizhou.

[0021] Of the components used in this invention, the aminated cellulose nanocrystals are derived from natural cellulose, and the polyglutamic acid is a product of microbial fermentation. Both are natural biodegradable materials that can naturally degrade within the rice plant after application, posing no risk of residue and not affecting the safety of rice consumption. When uniconazole and brassinolide are loaded onto the nanocarrier, their utilization rate is improved, and the application amount is reduced by 30% compared to conventional methods, thus lowering the risk of pesticide residue.

[0022] Calculations show that the material cost per mu (approximately 0.067 hectares) for the method of this invention is 7.55-30.18 yuan (based on 500 yuan / kg of nanocellulose and 30 yuan / kg of polyglutamic acid), the drone operation cost is approximately 15 yuan / mu, and the total cost per spray is 22.55-45.18 yuan. Since only 1-2 sprays are needed throughout the entire growth period, the total cost per mu per season is 30-90 yuan, saving 25-30% compared to conventional chemical growth control (requiring 2-3 sprays, costing 40-90 yuan / mu). If a nanocellulose production line is built, the cost can be further reduced to 15-20 yuan / mu per application. This cost level is feasible for promotion in rice cultivation in Guizhou. Detailed Implementation

[0023] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. The described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0024] Experimental description: Trial period: April 2025 to October 2025 Experimental location: Planting base in Meitan County, Zunyi City, Guizhou Province Experimental variety: Extra-long grain rice (plant height 185cm, single panicle grain length 9.2mm) Planting method: manual transplanting, row spacing 50cm, plant spacing 25cm Area of ​​each treatment area: 30m² (6m × 5m) Number of repetitions: Each treatment was repeated 3 times, using randomized block arrangements. Total experimental area: 8 treatments × 3 replicates × 30m² = 720m² (approximately 1.08 acres), plus protection rows. Sowing time: April 15, 2025 (seedling raising) Transplanting date: May 10, 2025 Spraying time: June 20, 2025 (at the beginning of jointing stage, when the length of the 2nd-3rd internode at the base of the plant reaches 1.5cm). Second spraying date: June 28, 2025 (Example 3 only) Survey period: Plant height and internode length were surveyed 30 days after spraying (July 20, 2025); lodging rate was surveyed during the grain-filling stage (August 15, 2025); and yield was measured at maturity (October 10, 2025). Example

[0025] This embodiment provides a method for cultivating ultra-long grain rice, including the following steps: (1) Selected extra-long grain rice seeds with a plant height of 185cm and a single panicle grain length of 9.2mm, seedlings were raised on April 15, 2025, and transplanted to the experimental field in Meitan, Guizhou on May 10, 2025. The planting row spacing was 50cm and the plant spacing was 25cm. Each plot area was 30m², and there were 3 replicates.

[0026] (2) Preparation of amination cellulose nanocrystals: cellulose nanocrystals were dispersed in water, polyethyleneimine was added, and the mixture was stirred at 60°C for 6 hours. After centrifugation, washing and drying, amination cellulose nanocrystals were obtained with an average particle size of 120 nm and a zeta potential of +28 mV.

[0027] (3) Preparation of supported nanocellulose: Uniconazole and brassinolide were dissolved in ethanol and added to the aminated cellulose nanocrystal suspension obtained in step (2). The mixture was stirred for 18 hours, centrifuged, and dried. The loading of uniconazole was 10.2 wt% and the loading of brassinolide was 0.03 wt%.

[0028] (4) Preparation of spray solution: Disperse the supported nanocellulose and polyglutamic acid obtained in step (3) in water, adjust the pH to 5.0 with acetic acid, and prepare a spray solution. The mass concentration of supported nanocellulose in the spray solution is 1.2 g / L, and the mass concentration of polyglutamic acid is 120 mg / L. The weight-average molecular weight of the polyglutamic acid used is 1.2 million Daltons.

[0029] (5) Foliar spraying: On June 20, 2025, when the length of the 2nd-3rd internode at the base of the extra-long grain rice plant reaches 1.5cm, foliar spraying will be carried out using drones. The drone will fly at an altitude of 2.0m and the spraying flow rate will be 2.0L / mu. The spraying amount for each plot will be calculated based on the area. Example

[0030] This embodiment is basically the same as that of embodiment 1, except that in step (4), polyglutamic acid is replaced with sodium alginate oligosaccharide.

[0031] The experiment time, location, variety, planting method, plot area, and number of replicates were all the same as in Example 1.

[0032] Step (4) Preparation of spray solution: Disperse the supported nanocellulose and sodium alginate oligosaccharide obtained in step (3) in water, adjust the pH to 5.0 with acetic acid, and prepare a spray solution. The mass concentration of supported nanocellulose in the spray solution is 1.2 g / L, and the mass concentration of sodium alginate oligosaccharide is 120 mg / L.

[0033] The spraying time and method are the same as step (5) in Example 1. Example

[0034] This embodiment is basically the same as embodiment 1, except that a second spraying is added after step (5).

[0035] The experiment time, location, variety, planting method, plot area, and number of replicates were all the same as in Example 1.

[0036] Steps (1)-(4) are the same as steps (1)-(4) in Example 1.

[0037] Step (5) First foliar spray: Same as step (5) in Example 1.

[0038] Step (6) Second foliar spray: On June 28, 2025 (8 days after the first spray), the second foliar spray was carried out. During the second spray, the mass concentration of supported nanocellulose in the spray solution was 0.3 g / L, the mass concentration of polyglutamic acid remained unchanged (120 mg / L), and the other parameters were the same as those of the first spray. Example

[0039] This embodiment is basically the same as embodiment 1, except that the spray solution in step (4) also contains potassium silicate.

[0040] The experiment time, location, variety, planting method, plot area, and number of replicates were all the same as in Example 1.

[0041] Step (4) Preparation of spray solution: Disperse the supported nanocellulose, polyglutamic acid and potassium silicate obtained in step (3) in water, adjust the pH to 5.0 with acetic acid, and prepare the spray solution. The mass concentration of supported nanocellulose in the spray solution is 1.2 g / L, the mass concentration of polyglutamic acid is 120 mg / L, and the concentration of potassium silicate is 150 mg / L (calculated as SiO2).

[0042] The spraying time and method are the same as step (5) in Example 1.

[0043] Comparative Example 1: This comparative example is basically the same as Example 1, except that the loading treatment in steps (2) and (3) is not performed, and the uniconazole and brassinolide are directly dissolved in water at the same dosage and sprayed.

[0044] The experiment time, location, variety, planting method, plot area, and number of replicates were all the same as in Example 1.

[0045] (1) Same as step (1) in Example 1.

[0046] (2) Preparation of spray solution: Disperse uniconazole and brassinolide in water to prepare a spray solution. The mass concentration of uniconazole in the spray solution is 120 mg / L (equivalent to the concentration of about 1.2 g of uniconazole in 12 g of loaded nanocellulose in Example 1, after conversion based on 30 L of water per mu), and the mass concentration of brassinolide is 0.36 mg / L.

[0047] (3) Foliar spraying: June 20, 2025, same as step (5) in Example 1.

[0048] Comparative Example 2: This comparative example is basically the same as Example 1, except that polyglutamic acid is not added in step (4).

[0049] The experiment time, location, variety, planting method, plot area, and number of replicates were all the same as in Example 1.

[0050] (1) Same as step (1) in Example 1.

[0051] (2) Same as step (2) in Example 1.

[0052] (3) Same as step (3) in Example 1.

[0053] (4) Preparation of spray solution: Disperse the supported nanocellulose obtained in step (3) in water, adjust the pH to 5.0 with acetic acid, and prepare a spray solution. The mass concentration of supported nanocellulose in the spray solution is 1.2 g / L, and it does not contain polyglutamic acid.

[0054] (5) Foliar spraying: June 20, 2025, same as step (5) in Example 1.

[0055] Comparative Example 3: This comparative example uses the seed soaking treatment method in the existing technology: The experiment time, location, variety, planting method, plot area, and number of replicates were all the same as in Example 1.

[0056] (1) Same as step (1) in Example 1.

[0057] (2) Preparation of seed soaking solution: Dissolve uniconazole, brassinolide and S-inducer in water to prepare a seed soaking solution. The concentration of uniconazole in the solution is 50 mg / L, the concentration of brassinolide is 0.05 mg / L and the concentration of S-inducer is 0.2 mg / L.

[0058] (3) Seed soaking treatment: On April 10, 2025, the extra-long grain rice seeds from step (1) were mixed with the soaking agent aqueous solution at a weight ratio of 1:1.5 and soaked at 25°C for 48 hours. The seeds were then drained. Seedlings were raised on April 15, 2025, and transplanted on May 10, 2025. Subsequent management was the same as in Example 1.

[0059] Comparative Example 4: This comparative example uses conventional planting methods without any growth control treatment.

[0060] The experiment time, location, variety, planting method, plot area, and number of replicates were all the same as in Example 1.

[0061] (1) Same as step (1) in Example 1.

[0062] (2) Water and fertilizer management and pest and disease control are carried out in accordance with conventional methods. No growth regulators are sprayed and no seed soaking is performed. Example

[0063] The applicant investigated plant height and the length of the 3rd-4th internode at the base on July 20, 2025 (30 days after spraying), lodging rate on August 15, 2025 (grain-filling stage), and yield on October 10, 2025 (maturity stage). The results are shown in Table 1.

[0064]

[0065] Note: The lodging rate is based on data collected after a level 6 gale occurred during the grouting period on August 15, 2025.

[0066] As can be seen from Table 1: Comparison of Example 1 and Comparative Example 1: Example 1 used aminated cellulose nanocrystals loaded with uniconazole and brassinolide. The plant height was reduced by 16 cm compared to Comparative Example 1, the lodging rate was reduced by 11.4 percentage points, and the yield per mu (667 square meters) increased by 43 kg. This indicates that the nano-loading technology significantly prolonged the duration of growth control and improved the growth control effect.

[0067] Comparison of Example 1 and Comparative Example 2: Example 1, with the addition of polyglutamic acid, resulted in a 6 cm reduction in plant height, a 4.1 percentage point decrease in lodging rate, and a 20 kg increase in yield per mu compared to Comparative Example 2. This indicates that the combination of polyglutamic acid and growth regulators has a synergistic effect.

[0068] Comparison of Example 1 and Comparative Example 3: Example 1 used foliar spraying at the jointing stage, while Comparative Example 3 used seed soaking treatment before sowing. The plant height of Example 1 was 26 cm lower than that of Comparative Example 3, the lodging rate was reduced by 24.2 percentage points, and the yield per mu (667 square meters) increased by 47 kg. This indicates that precise application of pesticides at the jointing stage is significantly more effective than seed soaking treatment during the seedling stage.

[0069] Comparison of Example 1 and Comparative Example 4: The plant height of Example 1 was 30 cm lower than that of Comparative Example 4, the lodging rate was reduced by 31.0 percentage points, and the yield per mu (667 square meters) increased by 60 kg. This demonstrates that the method of the present invention has a significant effect on controlling excessive growth and preventing lodging in ultra-long grain rice.

[0070] Example 3, based on Example 1, added a second spray, which further reduced the plant height to 148cm, reduced the lodging rate to 3.0%, and achieved a yield of 791kg per mu, the highest among all treatments.

[0071] Example 4: Adding potassium silicate to the spray solution resulted in slightly better performance than in Example 1, but the differences were not significant.

[0072] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0073] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for cultivating extra-long grain rice, characterized in that, Includes the following steps: (1) Select extra-long grain rice seeds with a plant height ≥150cm and a single panicle grain length ≥8.5mm, and transplant them to paddy fields after raising seedlings; (2) Prepare aminated cellulose nanocrystals, wherein the average particle size of the aminated cellulose nanocrystals is 50-200 nm; (3) Uniconazole and brassinolide were loaded onto aminated cellulose nanocrystals to obtain supported nanocellulose; the loading amount of uniconazole was 5-15 wt%, and the loading amount of brassinolide was 0.01-0.05 wt%. (4) Disperse the supported nanocellulose and polyglutamic acid in water, adjust the pH to 4.5-5.5, and prepare a spray solution; the mass concentration of the supported nanocellulose in the spray solution is 0.5-2 g / L, and the mass concentration of polyglutamic acid is 50-200 mg / L; (5) When the length of the second-third internode at the base of the ultra-long grain rice plant reaches 1-2 cm, a drone is used for foliar spraying. The drone flies at a height of 1.5-2.5 m and sprays at a flow rate of 1.5-2.5 L / mu.

2. The method according to claim 1, characterized in that: In step (2), the preparation method of the amination cellulose nanocrystals is as follows: disperse cellulose nanocrystals in water, add polyethyleneimine or ethylenediamine, stir and react at 50-70℃ for 4-8 hours, centrifuge, wash, and dry.

3. The method according to claim 1, characterized in that: In step (3), the loading method is as follows: dissolve uniconazole and brassinolide in ethanol, add them to the aminated cellulose nanocrystal suspension, stir for 12-24 hours, centrifuge, and dry.

4. The method according to claim 1, characterized in that: The polyglutamic acid has a weight-average molecular weight of 500,000 to 2,000,000 Daltons.

5. The method according to claim 1, characterized in that: In step (4), the polyglutamic acid is replaced with sodium alginate oligosaccharide at a concentration of 50-200 mg / L.

6. The method according to claim 1, characterized in that: After the spraying in step (5), a second spraying is carried out at an interval of 7-10 days. The mass concentration of the supported nanocellulose in the spray solution during the second spraying is 0.2-0.5 g / L.

7. The method according to claim 1, characterized in that: The surface of the aminated cellulose nanocrystals contains amino groups, and its zeta potential is +20mV to +40mV.

8. The method according to claim 1, characterized in that: In step (4), the spray solution also contains potassium silicate at a concentration of 100-200 mg / L.

Images