Method for planting rice with high glucan content

Abstract

The invention relates to the technical field of rice planting, and particularly provides a planting method of rice with high glucan content. The method comprises the following steps: step 1, preparing a nutrient solution containing beta-glucan after enzymolysis; 2, foliage spraying is conducted in stages according to the rice growth cycle, wherein the spraying stages comprise the tillering stage, the booting stage, the heading stage and the milk-ripe stage; wherein the spraying time is controlled from sunrise to 10 a.m.. According to the method, natural beta-glucan is precisely cut into active fragments through a beta-1, 3-glucanase and cellulase sequential enzymolysis process, the particle size of the active fragments is perfectly matched with the pore diameter of rice pores, and the leaf surface absorption efficiency is improved by combining a growth-period gradient spraying strategy and a pore rhythm spraying window.

Description

Technical Field

[0001] The invention relates to the technical field of rice planting, and in particular to a method for planting rice with high glucan content. Background Art

[0002] β-glucan, an active polysaccharide with immunomodulatory properties, has significant benefits in cancer prevention, blood sugar reduction, and skin repair. Traditionally, its extraction relies on rare fungi such as Ganoderma lucidum and Agaricus blazei, which is costly and has low bioavailability. Rice, a staple food crop, naturally contains β-glucan in its endosperm cell walls, but the content in regular rice is only 0.3-0.5%, insufficient to meet the demand for functional foods.

[0003] Existing technologies attempt to increase the content through microbial fermentation, gene editing or physical treatment, but have different defects. For example, the microbial seed soaking method relies on multiple sprayings of bacterial liquid fertilizer, which prolongs the cycle and results in insufficient biological activity of β-glucan in the resulting rice; the magnetic additive-assisted method requires gradient spraying, which is complicated to operate and easily brings the risk of excessive chemical residues.

[0004] In response to the above technical pain points, a simpler rice cultivation method with better β-glucan enrichment effect is urgently needed. Summary of the Invention

[0005] In view of this, the present invention proposes a method for growing rice with high glucan content.

[0006] The technical solution of the present invention is achieved as follows: The present invention provides a method for growing rice with high glucan content, comprising the following steps:

[0007] Step 1: preparing a nutrient solution containing active fragments of β-glucan after enzymatic hydrolysis;

[0008] Step 2: spraying the rice leaves in stages according to the rice growth cycle, including the tillering stage, booting stage, heading stage, and milky stage;

[0009] The spraying time is controlled from sunrise to 10 am.

[0010] Active fragments obtained after enzymatic hydrolysis of β-glucan can overcome foliar absorption barriers. Foliar spraying from the tillering to milky stages precisely matches the carbon metabolic flux from photosynthate to grain. Spraying during the stomatal opening window from sunrise to 10:00 a.m. maximizes the active stomatal absorption pathway. Compared to traditional root spraying, this method increases the β-glucan content in rice, maintains a complete natural glycosidic bond structure, enhances biological activity, and improves functionality and ecological benefits.

[0011] In some embodiments, the spraying environment temperature is 20-28° C., and the relative humidity is not less than 65%.

[0012] Rice leaves' stomata open optimally between 20 and 28°C. At this temperature, cell membrane permeability increases, allowing macromolecular active substances like β-glucan to enter the leaves through active absorption pathways through the stomata. This temperature range closely matches the optimum temperature for rice photosynthesis, simultaneously promoting the transport of photosynthetic products to the grain. At this temperature, the droplet evaporation rate is moderate, extending its retention time on the leaf surface while preventing the excessively thick liquid film caused by low temperatures from hindering nutrient penetration.

[0013] In some embodiments, the enzymatic hydrolysis method comprises: first treating with β-1,3-glucanase at pH 5.5 and 50° C. for 3 hours, and then treating with cellulase at pH 4.8 and 45° C. for 1 hour.

[0014] The enzymatic hydrolysis products are inactivated at high temperature, purified and concentrated to obtain the active fragments after enzymatic hydrolysis, which are used to prepare the nutrient solution. Through the sequential treatment of β-1,3-glucanase and cellulase, the β-glucan main chain and side chain are precisely cut to generate a 5×10 4 ~1×10 5 The active fragment of Da, with a particle size highly compatible with rice stomata, significantly improves foliar absorption efficiency. After enzymatic hydrolysis, heat inactivation combined with ultrafiltration purification removes over 99% of residual enzymes and buffers, ensuring only the active fragment remains in the spray solution. This ultimately increases the β-glucan content in the grain while maintaining the natural β-1,3 / 1,6 bond ratio (3:1±0.2), resulting in high retention of biological activity.

[0015] In some embodiments, the β-glucan-containing nutrient solution comprises, by weight percentage, 0.1-0.3% of enzymatically hydrolyzed β-glucan fragments, 0.1-0.3% of polyoxyethylene castor oil, 5-10% of nano-silica sol, and the balance water.

[0016] The β-glucan nutrient solution achieves efficient foliar absorption and targeted enrichment through the synergistic effect of its functional ingredients. It consists of enzymatically active fragments, polyoxyethylene castor oil, nano-silica sol, and the balance water. The polyoxyethylene castor oil reduces the droplet surface tension to 28-32 mN / m, enhancing droplet spreadability. The nano-silica sol forms a porous network through hydrogen bonding, extending the active fragment's foliar retention time to over 45 minutes. Its pH-responsive sustained-release properties enable precise controlled release during the stomatal absorption window.

[0017] In some embodiments, the spraying rate during the tillering stage is 100-150 ml / mu, the spraying rate during the booting stage is 150-200 ml / mu, the spraying rate during the heading stage is 180-200 ml / mu, and the spraying rate during the milky stage is 200 ml / mu.

[0018] A gradient spraying strategy across growth stages precisely matches the physiological needs of rice: low-dose spraying during the tillering stage promotes tiller primordium differentiation, avoiding redundant carbon metabolism; increased spraying during the booting stage activates spikelet differentiation enzymes, increasing grain number per ear; heading, combined with the need to extend the flag leaf functional period, strengthens the transport of photosynthetic products to the ear; and high-dose spraying during the milky stage targets endosperm cell wall thickening, improving β-glucan deposition efficiency. This gradient approach, combined with stomatal rhythm spraying and nano-silica sol slow-release technology, achieves higher effective β-glucan absorption per mu compared to the equal-dose spraying method, and increases nutrient solution utilization to , while simultaneously reducing the risk of pesticide residues.

[0019] In some embodiments, the mass percentage of β-glucan fragments after enzymatic hydrolysis in the nutrient solution sprayed during the tillering stage is 0.1%, the mass percentage of β-glucan fragments after enzymatic hydrolysis in the nutrient solution sprayed during the booting stage is 0.15%, the mass percentage of β-glucan fragments after enzymatic hydrolysis in the nutrient solution sprayed during the heading stage is 0.18%, and the mass percentage of β-glucan fragments after enzymatic hydrolysis in the nutrient solution sprayed during the milky stage is 0.2%.

[0020] By dynamically adjusting the concentration of β-glucan active fragments in the nutrient solution according to the growth stage (0.1% in the tillering stage → 0.2% in the milky stage), the direction of rice carbon metabolism flow and organ development needs can be precisely adapted. A low concentration (0.1%) in the tillering stage promotes the differentiation of tiller primordia and avoids the inhibition of polar transport of auxin (IAA) by high concentrations; increasing it to 0.15% in the booting stage activates spikelet differentiation enzymes and increases the number of grains per ear; 0.18% in the heading stage strengthens the photosynthetic capacity of the flag leaf and prolongs the functional period; a high concentration of 0.2% in the milky stage targets and regulates the endosperm PCD process, thereby improving the efficiency of β-glucan deposition. This gradient design combines stomatal rhythm spraying (6:00-10:00 in the morning) with the slow release of nano-silica sol to achieve an increase in the effective absorption per mu, with the grain β-glucan content reaching 6.3-8.5% (dry weight), and the stability of the glycosidic bond structure is better than that of the physical extraction method.

[0021] In some embodiments, the β-glucan nutrient solution further comprises 0.05-0.1% humic acid, calculated as 100% by weight.

[0022] By adding 0.05-0.1% humic acid to the β-glucan nutrient solution, multiple synergistic effects are achieved: activating the NPR1 signaling pathway and the pattern recognition receptors LYK5 / CERK1, increasing rice disease resistance by 58%. Its carboxyl groups form a pH-responsive slow-release network with nano-silica sol, prolonging leaf retention and precisely matching stomatal rhythms. Ultimately, the β-glucan content in indica rice grains reaches 8.5% (dry weight), with a stable bond ratio of 3:1±0.05. This increases nitrogen, phosphorus, and potassium utilization, while reducing the incidence of ear rot.

[0023] By precisely controlling the particle size of nutrient solution droplets at 50-150μm, the leaf absorption efficiency is maximized: this particle size range balances the defects of coarse droplets that are easy to drift (>200μm) and fine droplets that are difficult to retain (<50μm), combined with nano-silica sol (5-10%) to form a porous carrier network, and the "microcapsule rupture effect" is used to evenly distribute the active fragments of β-glucan around the stomata; combined with polyoxyethylene castor oil to reduce surface tension, under a fan nozzle pressure of 0.3-0.5MPa, the droplet evaporation rate decreases and the leaf retention time is prolonged.

[0024] In some embodiments, when spraying, the droplet size of the nutrient solution is 50-150 μm.

[0025] In some embodiments, the planting method is used for growing Indica rice.

[0026] In some embodiments, the β-glucan content in the rice grown by the planting method is not less than 6.3% (dry weight).

[0027] The present invention has the following beneficial effects compared to the prior art:

[0028] The present invention uses a sequential enzymatic hydrolysis process of β-1,3-glucanase and cellulase to accurately cut natural β-glucan into active fragments. The particle size of the active fragments is perfectly adapted to the stomatal aperture of rice. Combined with the gradient spraying strategy of different growth stages and the stomatal rhythm spraying window, the leaf absorption efficiency is improved. Combined with the pH-responsive sustained-release properties of nano-silica sol and the metabolic regulation function of humic acid, the β-glucan content in indica rice grains is increased, and the β-1,3 / 1,6 bond ratio is stabilized at 3:1±0.05, while the risk of pesticide residues is simultaneously reduced, achieving dual breakthroughs of functional enhancement and eco-friendliness. DETAILED DESCRIPTION

[0029] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which embodiments of the present invention belong. If the definitions set forth in this section are contrary to or otherwise inconsistent with definitions set forth in the patents, patent applications, published patent applications, and other publications incorporated herein by reference, the definitions listed in this section take precedence over the definitions incorporated herein by reference.

[0031] Unless otherwise specified, the methods used in the following examples are conventional methods. The materials, reagents, and instruments used are conventional materials, reagents, and instruments in the art, unless otherwise specified, and can be obtained commercially by those skilled in the art.

[0032] When an amount, concentration or other value or parameter is expressed as a range, a preferred range or a range defined by a series of upper preferred values and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pairing of any upper range limit or preferred value with any lower range limit or preferred value, regardless of whether the range is disclosed alone. For example, when a range "1 to 5" is disclosed, the described range should be interpreted as including the ranges "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5", etc. When a numerical range is described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within the range. In the present specification and claims, range definitions may be combined and / or interchanged, and if not otherwise stated, such ranges include all subranges contained therein.

[0033] The following examples and comparative examples were all conducted in the same experimental rice field, using the Keyou 21 variety.

[0034] Preparation Example 1

[0035] Preparation of β-glucan active fragments:

[0036] For the β-glucan substrate, birchwood β-glucan was treated with β-1,3-glucanase (5000 U / g activity) at pH 5.5 and 50°C for 3 hours. Cellulase (8000 U / g activity) was then treated at pH 4.8 and 45°C for 1 hour. After heat inactivation at 120°C for 15 minutes, the target fragment was retained using a 100 kDa ultrafiltration membrane and concentrated to a solids content of 15%.

[0037] Preparation Example 2

[0038] Preparation of β-glucan active fragments:

[0039] For the β-glucan substrate, birchwood β-glucan was treated with β-1,3-glucanase (5000 U / g activity) at pH 5.5 and 50°C for 4 hours. Cellulase (8000 U / g activity) was then treated at pH 4.8 and 45°C for 1 hour. After heat inactivation at 120°C for 15 minutes, the target fragment was retained using a 100 kDa ultrafiltration membrane and concentrated to a solids content of 15%.

[0040] Preparation Example 3

[0041] Preparation of β-glucan active fragments:

[0042] For the β-glucan substrate, birchwood β-glucan was treated with β-1,3-glucanase (enzyme activity 5000 U / g) at pH 5.5 and 50°C for 3 h. After heat inactivation at 120°C for 15 min, the target fragment was retained using a 100 kDa ultrafiltration membrane and concentrated to a solid content of 15%.

[0043] Example 1

[0044] Nutrient solution formula:

[0045] Preparation Example 1 β-glucan active fragment: 0.2% (molecular weight 8.2×10 4 Da);

[0046] Humic acid: 0.08% (carboxyl content 12.5mmol / g)

[0047] Nano-silica sol: 8% (particle size 5-8nm, specific surface area 320m 2 / g)

[0048] Polyoxyethylene castor oil: 0.2%.

[0049] Application method:

[0050] Tillering period: 06:00-08:00, spray 0.1% solution on leaves (median droplet size 110 μm), dosage 120 ml / mu.

[0051] Booting stage: spray 0.15% solution on leaves (median droplet size 90 μm) from 06:00 to 09:00, with a dosage of 180 ml / mu.

[0052] Heading period: spray 0.18% solution on leaves (median droplet size 85 μm) from 05:30 to 09:30, with a dosage of 200 ml / mu.

[0053] Milky stage: spray 0.2% solution on leaves (median droplet size 95μm) from 06:00 to 10:00, with a dosage of 200ml / mu.

[0054] Example 2

[0055] Nutrient solution formula:

[0056] Preparation Example 2 β-glucan active fragment: 0.2% (molecular weight 6.5×10 4 Da);

[0057] Humic acid: 0.08% (carboxyl content 12.5mmol / g)

[0058] Nano-silica sol: 8% (particle size 5-8nm, specific surface area 320m 2 / g)

[0059] Polyoxyethylene castor oil: 0.2%.

[0060] Application method:

[0061] Tillering period: 06:00-08:00, spray 0.1% solution on leaves (median droplet size 110 μm), dosage 120 ml / mu.

[0062] Booting stage: spray 0.15% solution on leaves (median droplet size 90 μm) from 06:00 to 09:00, with a dosage of 180 ml / mu.

[0063] Heading period: spray 0.18% solution on leaves (median droplet size 85 μm) from 05:30 to 09:30, with a dosage of 200 ml / mu.

[0064] Milky stage: spray 0.2% solution on leaves (median droplet size 95μm) from 06:00 to 10:00, with a dosage of 200ml / mu.

[0065] Example 3

[0066] Nutrient solution formula:

[0067] Preparation Example 1 β-glucan active fragment: 0.2% (molecular weight 8.2×10 4 Da);

[0068] Nano-silica sol: 8% (particle size 5-8nm, specific surface area 320m 2 / g)

[0069] Polyoxyethylene castor oil: 0.2%.

[0070] Application method:

[0071] Tillering period: 06:00-08:00, spray 0.1% solution on leaves (median droplet size 110 μm), dosage 120 ml / mu.

[0072] Booting stage: spray 0.15% solution on leaves (median droplet size 90 μm) from 06:00 to 09:00, with a dosage of 180 ml / mu.

[0073] Heading period: spray 0.18% solution on leaves (median droplet size 85 μm) from 05:30 to 09:30, with a dosage of 200 ml / mu.

[0074] Milky stage: spray 0.2% solution on leaves (median droplet size 95μm) from 06:00 to 10:00, with a dosage of 200ml / mu.

[0075] Comparative Example 1

[0076] Nutrient solution formula:

[0077] Preparation Example 1 β-glucan active fragment: 0.2% (molecular weight 8.2×10 4 Da);

[0078] Humic acid: 0.08% (carboxyl content 12.5mmol / g)

[0079] Nano-silica sol: 8% (particle size 5-8nm, specific surface area 320m 2 / g)

[0080] Polyoxyethylene castor oil: 0.2%.

[0081] Application method:

[0082] Tillering period: 06:00-08:00, spray 0.1% solution on leaves (median droplet size 210 μm), dosage 120 ml / mu.

[0083] Booting stage: spray 0.15% solution on leaves (median droplet size 200 μm) from 06:00 to 09:00, with a dosage of 180 ml / mu.

[0084] Heading period: spray 0.18% solution on leaves (median droplet size 210 μm) from 05:30 to 09:30, with a dosage of 200 ml / mu.

[0085] Milky stage: spray 0.2% solution on leaves (median droplet size 220 μm) from 06:00 to 10:00, with a dosage of 200 ml / mu.

[0086] Comparative Example 2

[0087] Nutrient solution formula:

[0088] Preparation Example 3 β-glucan active fragment: 0.2% (molecular weight 2×10 5 Da);

[0089] Humic acid: 0.08% (carboxyl content 12.5mmol / g)

[0090] Nano-silica sol: 8% (particle size 5-8nm, specific surface area 320m 2 / g)

[0091] Polyoxyethylene castor oil: 0.2%.

[0092] Application method:

[0093] Tillering period: 06:00-08:00, spray 0.1% solution on leaves (median droplet size 110 μm), dosage 120 ml / mu.

[0094] Booting stage: spray 0.15% solution on leaves (median droplet size 90 μm) from 06:00 to 09:00, with a dosage of 180 ml / mu.

[0095] Heading period: spray 0.18% solution on leaves (median droplet size 85 μm) from 05:30 to 09:30, with a dosage of 200 ml / mu.

[0096] Milky stage: spray 0.2% solution on leaves (median droplet size 95μm) from 06:00 to 10:00, with a dosage of 200ml / mu.

[0097] Comparative Example 3

[0098] Use traditional planting methods.

[0099] Comparative Example 4

[0100] The only difference between this comparative example and Example 1 is that the compound is sprayed on the soil.

[0101] The rice obtained from the above different examples and comparative examples was statistically analyzed for indicators including β-glucan content (dry weight), yield per mu, nitrogen, phosphorus and potassium utilization, rice blast incidence, and organophosphorus residue.

[0102] The β-glucan content (dry weight) was determined by enzyme-colorimetry. The sample was hydrolyzed by β-glucanase and β-glucosidase to generate glucose. Glucose oxidase was then reacted with a color developer to generate red quinone compounds. The absorbance was measured at a wavelength of 510 nm to calculate the content.

[0103] Nitrogen, phosphorus and potassium utilization rate, by marking nitrogen (such as 15 N), phosphorus ( 32 P), potassium ( 42 K) isotopes, which measure the ratio of crop absorption to the amount of fertilizer applied.

[0104] Organophosphorus residues were detected by gas chromatography.

[0105] The results are shown in the following table:

[0106]

[0107] Comparison between Preparation Example 1 and Preparation Example 2: The difference in β-1,3-glucanase treatment time resulted in a difference in molecular weight, verifying the regulatory effect of enzymatic hydrolysis time on the molecular weight of the active fragment.

[0108] Comparison between Preparation Example 1 and Preparation Example 3: Preparation Example 3 did not use secondary treatment with cellulase, resulting in a significant increase in molecular weight, demonstrating the importance of cellulase in further hydrolysis of β-glucan fragments.

[0109] Comparison between Example 1 and Example 3: After humic acid was removed from Example 3, the utilization rate of nitrogen, phosphorus and potassium decreased by 15%-17%, indicating the synergistic effect of humic acid on nutrient absorption.

[0110] Comparison between Example 1 and Comparative Example 1: When the droplet size increases to above 200 μm, the nutrient utilization rate decreases by 5%-10%, verifying the direct effect of the droplet size on the leaf absorption efficiency.

[0111] Comparison between Example 1 and Comparative Example 4: Compared with foliar spraying, soil spraying reduced the β-glucan content by 38.8%, and the utilization rate of nitrogen, phosphorus and potassium decreased by 7%-13%, indicating that foliar spraying has a significant advantage in the absorption of active ingredients.

[0112] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for growing rice with high glucan content, characterized in that: The steps include: Step 1: preparing a nutrient solution containing active fragments of β-glucan after enzymatic hydrolysis; Step 2: spraying the rice leaves in stages according to the rice growth cycle, including the tillering stage, booting stage, heading stage, and milky stage; The spraying time is controlled from sunrise to 10 am.

2. The method for growing rice with high glucan content according to claim 1, wherein: The spraying environment temperature is 20-28℃ and the relative humidity is not less than 65%.

3. The method for growing rice with high glucan content according to claim 1, wherein: The enzymatic hydrolysis method includes: first treating with β-1,3-glucanase at pH 5.5 and 50°C for 3 hours, and then treating with cellulase at pH 4.8 and 45°C for 1 hour.

4. The method for growing rice with high glucan content according to claim 3, wherein: The beta-glucan-containing nutrient solution comprises, by weight percentage, 0.1-0.3% of enzymatically hydrolyzed beta-glucan fragments, 0.1-0.3% of polyoxyethylene castor oil, 5-10% of nano-silica sol and the balance of water.

5. The method for growing rice with high glucan content according to claim 4, wherein: The spraying amount during the tillering stage is 100-150ml / mu, the spraying amount during the booting stage is 150-200ml / mu, the spraying amount during the heading stage is 180-200ml / mu, and the spraying amount during the milky stage is 200ml / mu.

6. The method for growing rice with high glucan content according to claim 5, wherein: In the nutrient solution sprayed during the tillering stage, the mass percentage of β-glucan fragments after enzymatic hydrolysis was 0.1%, in the nutrient solution sprayed during the booting stage, the mass percentage of β-glucan fragments after enzymatic hydrolysis was 0.15%, in the nutrient solution sprayed during the heading stage, the mass percentage of β-glucan fragments after enzymatic hydrolysis was 0.18%, and in the nutrient solution sprayed during the milky stage, the mass percentage of β-glucan fragments after enzymatic hydrolysis was 0.2%.

7. The method for growing rice with high glucan content according to claim 4, wherein: The beta-glucan nutrient solution further comprises 0.05-0.1% humic acid, calculated based on 100% by weight.

8. The method for growing rice with high glucan content according to claim 1, wherein: When spraying, the droplet size of the nutrient solution is 50-150μm.

9. The method for growing rice with high glucan content according to claim 1, wherein: The planting method is used for planting indica rice.

10. The method for growing rice with high glucan content according to claim 1, wherein: The beta-glucan content in the rice grown by the planting method is not less than 6.3% (dry weight).

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