A method to increase the polysaccharide content of Polygonatum sibiricum

Abstract

This invention provides a method for increasing the polysaccharide content of Polygonatum sibiricum, belonging to the field of plant cultivation technology. The method involves applying selenium fertilizer to the leaves of Polygonatum sibiricum 1-2 times via foliar spraying during April-June of the first, second, and third years after planting; and applying selenium fertilizer to the soil of the planting area 1-2 times via root application during September-October of the third year. Harvesting can begin in the same year after the fruit matures and the stems loom. This invention not only provides a new pathway for selenium supplementation in the human body but also improves the quality of Polygonatum sibiricum, thus enhancing its medicinal efficacy.

Description

Technical Field

[0001] This invention belongs to the field of plant cultivation technology and relates to a method for increasing the polysaccharide content of Polygonatum odoratum using selenium fertilizer. Specifically, it relates to a method for increasing the polysaccharide content of Polygonatum odoratum using a selenium fertilizer formed by combining sodium selenite, D-galacturonic acid, galactose and glucose. Background Technology

[0002] Polygonatum cyrtonema Hua is a perennial herb belonging to the genus Polygonatum in the family Liliaceae. Its rhizome is used medicinally and is a traditional Chinese medicine with both medicinal and edible properties. Polygonatum is also considered a promising new high-quality coarse grain that does not require much farmland. Polysaccharides are the main active ingredients in Polygonatum, possessing pharmacological effects such as immune regulation, antioxidation, antitumor activity, and lowering blood sugar and lipids. Appropriate amounts of selenium (Se) can promote photosynthesis and nutrient absorption, thus benefiting plant growth and the accumulation of polysaccharides, the main active ingredients in medicinal plants such as Astragalus membranaceus, Codonopsis pilosula, Dendrobium nobile, and Panax notoginseng. Therefore, artificially increasing the polysaccharide content of Polygonatum cyrtonema rhizomes through Se injection is beneficial for enhancing its medicinal value.

[0003] Meanwhile, selenium (Se), as an essential micronutrient for the human body, has functions such as enhancing immunity, preventing cardiovascular diseases, and fighting cancer. In my country, 72% of the population is deficient in selenium, and edible plant parts are the main dietary source for meeting human selenium needs. Therefore, exogenous selenium application not only helps increase the content of Polygonatum polysaccharides and enhance its medicinal value, but also provides a new way for the human body to supplement selenium. However, current technology does not yet disclose a method for increasing the content of Polygonatum polysaccharides through selenium. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a method for increasing the polysaccharide content of Polygonatum sibiricum using selenium fertilizer. Se not only increases the polysaccharide content of medicinal plants but also combines with polysaccharides to form selenium polysaccharides, which generally exhibit higher bioactivity than both Se and polysaccharides, and possess low toxicity and high bioavailability. Therefore, exogenous Se can increase polysaccharide content and promote the formation of selenium polysaccharides, which is beneficial for enhancing the medicinal value of Polygonatum sibiricum and can also provide a theoretical basis for the development of related functional foods and pharmaceuticals.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A method to increase the polysaccharide content of Polygonatum sibiricum involves applying selenium fertilizer to the leaves of Polygonatum sibiricum by foliar spraying 1-2 times each from April to June in the first, second, and third years after planting; and applying selenium fertilizer to the soil of Polygonatum sibiricum by root application 1-2 times from September to October in the third year after planting. The fruit can be harvested after it matures and the stems fall over in the same year.

[0007] Considering the dose-dependent nature of selenium's beneficial biological effects, exogenous selenium application is carried out through foliar spraying during the leaf growth period of *Polygonatum sibiricum* from April to June each year. This not only effectively controls the selenium intake of *Polygonatum sibiricum* but also fully utilizes the technical advantages of selenium in promoting photosynthesis in *Polygonatum sibiricum* leaves, promoting plant growth, and providing a carbon source for *Polygonatum sibiricum* synthesis. Simultaneously, combined with root application of selenium in the final year before harvest, close to the harvest period, this effectively increases the selenium content of the rhizomes and provides conditions for selenium polysaccharide synthesis, thus contributing to improved quality of *Polygonatum sibiricum*.

[0008] Furthermore, the intercropping method described herein follows these steps:

[0009] (1) Site selection: Select open areas or forest edges of fir, pine, bamboo and other trees at an altitude of 250m-1000m, with a canopy density of 0.5-0.6 and a slope of <25°.

[0010] (2) Land preparation: Apply 1000-1500 kg / mu of well-rotted farmyard manure and 20-25 kg / mu of calcium magnesium phosphate as base fertilizer. Then, deep plow in horizontal strips along the contour lines to a depth of 20-30 cm, harrow finely, and mix the fertilizer and soil thoroughly.

[0011] (3) Planting: The rhizomes of Polygonatum are planted in winter, from October to November. The rhizome seedlings and seedlings are planted in early spring after they emerge, with a plant spacing of 30-40cm.

[0012] (4) Selenium fertilizer preparation: a solution formed by mixing sodium selenite, galactose, D-galacturonic acid and glucose in a certain proportion.

[0013] Acidic conditions are conducive to improving the bioavailability of Se. For example, the pH of D-galacturonic acid solution is usually 5.0-6.0, and the combination of the two will promote the absorption of Se by Polygonatum. At the same time, D-galacturonic acid is rich in hydroxyl and carboxyl groups, which easily bind with Se, thus helping to maintain the stability of Se's valence state. In addition, D-galacturonic acid, galactose, and glucose are all precursors of Polygonatum polysaccharides. The introduction of these substances will provide more raw materials for the synthesis of Polygonatum polysaccharides, which is beneficial to the biosynthesis of Polygonatum polysaccharides.

[0014] (5) Selenium fertilizer application: In the first, second and third years of planting, apply selenium fertilizer to the leaves of Polygonatum 1-2 times by foliar spraying in April-June each year; in the third year of planting, apply selenium fertilizer to the soil of Polygonatum 1-2 times by root application in October-December.

[0015] (6) Harvesting: In the third year of planting, after the fruit is ripe and the stems have fallen over, the underground rhizomes are dug up.

[0016] Furthermore, the soil in the area should be red or yellow soil with a pH of 5.5-6.5, and the soil texture should be loam, clay loam, or light sandy loam.

[0017] Furthermore, the selenium fertilizer is made by compounding sodium selenite and D-galacturonic acid to form a solution with a Se concentration of 10-200 mg / L and a D-galacturonic acid concentration of 10-200 mg / L. After stabilizing for 2-8 hours, galactose is added at a mass concentration of 0.1-1%, and after stabilizing for 1-2 hours, glucose is added at a mass concentration of 0.5-8%, and after stabilizing for 1-2 hours.

[0018] Furthermore, the root application method is as follows: lightly scrape off 2-5cm of topsoil and evenly spray selenium fertilizer solution within a 5-15cm range around the rhizome; the amount of selenium fertilizer applied to the roots is 0.2-0.8L / plant of Polygonatum.

[0019] Furthermore, the foliar spraying method is as follows: the selenium fertilizer solution is evenly sprayed onto the front and back of the Polygonatum leaves; the amount of selenium fertilizer used for foliar spraying is 0.4-1.0L / Polygonatum plant.

[0020] The beneficial effects of this invention are:

[0021] (1) By scientifically and rationally determining the formulation method of selenium fertilizer, a stable Se complex is formed under acidic conditions, thereby improving the bioavailability of Se and increasing the application efficiency of Se fertilizer.

[0022] (2) By scientifically and rationally determining the concentration, dosage and application period of selenium fertilizer, the Se content in the rhizome of Polygonatum odoratum can be increased, thereby providing a new way for the human body to supplement selenium.

[0023] (3) By scientifically and rationally determining the concentration, dosage and application period of selenium fertilizer, not only can more precursor substances be provided for the synthesis of Polygonatum polysaccharide, but also Se can be used to promote the accumulation of polysaccharide in rhizomes, thereby increasing the polysaccharide content in Polygonatum rhizomes and enhancing its efficacy.

[0024] (4) Because Polygonatum is rich in polysaccharides, it provides favorable conditions for the formation of Se polysaccharides in the rhizome, which promotes the improvement of Polygonatum quality. Detailed Implementation

[0025] To explain in detail the technical content, objectives, and effects of the technical solution, the following detailed description is provided in conjunction with specific embodiments.

[0026] Example 1

[0027] 1. Experimental Methods

[0028] (1) Site selection: Select an open area under a bamboo forest at an altitude of 250m, with a canopy density of 0.6 and a slope of 10°. The soil should be yellow soil with a pH of 5.5 and a loam texture.

[0029] (2) Land preparation: Apply 1000 kg / mu of well-rotted farmyard manure and 20 kg / mu of calcium magnesium phosphate as base fertilizer. Then, deep plow in horizontal strips to a depth of 20 cm along the contour lines, harrow finely, and mix the fertilizer with the soil thoroughly.

[0030] (3) Planting: The rhizomes of Polygonatum are planted in October, with a plant spacing of 30cm.

[0031] (4) Selenium fertilizer preparation: Prepare selenium fertilizer solutions according to the following formulas and conduct tests.

[0032] Selenium fertilizer solution 1: Sodium selenite solution with a Se concentration of 200 mg / L.

[0033] Selenium fertilizer solution 2: A solution with a Se concentration of 200 mg / L and a D-galacturonic acid concentration of 200 mg / L is prepared by combining sodium selenite and D-galacturonic acid and is stable for 8 hours.

[0034] Selenium fertilizer solution 3: A solution with a Se concentration of 200 mg / L and a D-galacturonic acid concentration of 200 mg / L is formed by compounding sodium selenite and D-galacturonic acid. After stabilizing for 8 hours, galactose is added at a mass concentration of 1%. After stabilizing for 2 hours, glucose is added at a mass concentration of 8%. After stabilizing for 2 hours, the solution is stabilized for another 2 hours.

[0035] Control solution: Use water as a control.

[0036] (5) Selenium fertilizer application: In May of the first, second and third years of planting Polygonatum, foliar spraying is used to evenly spray 0.2L of the above four solutions on the front and back of the leaves once; in October of the third year of planting Polygonatum, root application is used to lightly scrape the topsoil 5cm and evenly spray 0.4L of the above solutions once within a 10cm range around the rhizome.

[0037] (6) Harvesting: In the third year of planting, after the fruit is ripe and the stems have fallen over, the underground rhizomes are dug up.

[0038] 2. Experimental Results

[0039] The effects of applying the above four solutions to Polygonatum were compared. Polysaccharide content was determined by the H2SO4-anthrone method; after digestion with HNO3-HClO4, the selenium content in the rhizome was determined by atomic absorption spectrometry (AA-7000, Shimadzu, Japan). The experimental results of Polygonatum yield, polysaccharide content in rhizomes, and selenium content are shown in Table 1.

[0040] Table 1 Comparison of Polygonatum yield, rhizome polysaccharide, and Se content after application of different selenium fertilizer solutions.

[0041] Solution type Polygonatum yield (kg / mu) Polysaccharide content (%) Selenium content (mg / kg) Selenium fertilizer solution 1 1833 10.77 0.1073 Selenium fertilizer solution 2 1951 11.65 0.1139 Selenium fertilizer solution 3 2290 16.95 0.1978 control solution 1652 9.83 0.0878

[0042] By scientifically and rationally determining the configuration, concentration, and dosage of selenium fertilizer, the yield of Polygonatum sibiricum increased by 10.96-38.62%, the content of polysaccharides in roots and stems increased by 9.56-72.43%, and the selenium content increased by 0.22-1.25 times after root application and foliar spraying of selenium fertilizer.

[0043] Example 2

[0044] The specific steps of a method to increase the polysaccharide content of Polygonatum are as follows:

[0045] (1) Site selection: Select an open area under a Chinese fir forest at an altitude of 1000m, with a canopy density of 0.5 and a slope of 15°. The soil should be red soil with a pH of 6.1 and a clay loam texture.

[0046] (2) Land preparation: Apply 1200 kg / mu of well-rotted farmyard manure and 25 kg / mu of calcium magnesium phosphate as base fertilizer. Then, deep plow in horizontal strips to a depth of 30 cm along the contour lines, harrow finely, and mix the fertilizer with the soil thoroughly.

[0047] (3) Planting: The rhizomes of Polygonatum are planted in November with a spacing of 40cm between plants.

[0048] (4) Selenium fertilizer preparation: Sodium selenite and D-galacturonic acid are combined to form a solution with a Se concentration of 10 mg / L and a D-galacturonic acid concentration of 10 mg / L. After stabilizing for 2 hours, galactose is added at a mass concentration of 0.1%. After stabilizing for 1 hour, glucose is added at a mass concentration of 0.5%. After stabilizing for 1 hour, the solution is stabilized for 1 hour.

[0049] (5) Selenium fertilizer application: In June of the first, second and third years of planting Polygonatum, 0.8L of selenium fertilizer solution is sprayed evenly on the front and back of Polygonatum leaves once by foliar spraying; in November of the third year of planting Polygonatum, 1.0L of selenium fertilizer solution is sprayed evenly on the roots by lightly scraping the topsoil 2cm and spraying 1.0L of selenium fertilizer solution evenly twice within a 15cm range around the rhizome.

[0050] (6) Harvesting: In the third year of planting, after the fruit is ripe and the stems have fallen over, the underground rhizomes are dug up.

[0051] Using this method, the yield of Polygonatum can reach 2082 kg / mu, with a root and stem polysaccharide content of 12.88% and a selenium content of 0.1652 mg / kg.

[0052] Example 3

[0053] 1. Experimental Methods

[0054] (1) Site selection: Select an open area under a pine forest at an altitude of 800m, with a canopy density of 0.55 and a slope of 10°. The soil should be yellow soil with a pH of 6.0 and a loam texture.

[0055] (2) Land preparation: Apply 1200 kg / mu of well-rotted farmyard manure and 22 kg / mu of calcium magnesium phosphate as base fertilizer. Then, deep plow in horizontal strips to a depth of 25 cm along the contour lines, harrow finely, and mix the fertilizer with the soil thoroughly.

[0056] (3) Planting: The rhizomes of Polygonatum are planted in October with a spacing of 35cm between plants.

[0057] (4) Selenium fertilizer preparation: Sodium selenite and D-galacturonic acid are combined to form a solution with a Se concentration of 50 mg / L and a D-galacturonic acid concentration of 50 mg / L. After stabilizing for 2 hours, galactose is added at a mass concentration of 0.4%. After stabilizing for 1 hour, glucose is added at a mass concentration of 2%. After stabilizing for 1 hour, glucose is added.

[0058] (5) Selenium fertilizer application: Selenium fertilizer shall be applied according to the following methods.

[0059] Selenium fertilizer application method 1: In April of the first, second and third years after planting, apply 0.4L of selenium fertilizer solution evenly to the front and back of the leaves of Polygonatum odoratum once by foliar spraying.

[0060] Selenium fertilizer application method 2: In April of the first and second years after planting, apply 0.4L of selenium fertilizer solution evenly to the front and back of the leaves of Polygonatum sibiricum once by foliar spraying; in December of the third year after planting, apply 0.8L of selenium fertilizer solution evenly to the roots by lightly scraping away 4cm of topsoil and spraying 0.8L of selenium fertilizer solution evenly within a 5cm radius around the rhizome twice.

[0061] Selenium fertilizer application 3: In April of the first, second and third years of planting, apply 0.8L of selenium fertilizer solution evenly to the front and back of the leaves of Polygonatum sibiricum once by foliar spraying; in December of the third year of planting, apply 0.8L of selenium fertilizer solution evenly to the roots by lightly scraping the top 4cm of soil and spraying 0.8L of selenium fertilizer solution evenly within a 5cm range around the rhizome twice by root application.

[0062] No selenium fertilizer applied: The control group was treated with root application of water.

[0063] (6) Harvesting: In the third year of planting, after the fruit is ripe and the stems have fallen over, the underground rhizomes are dug up.

[0064] 2. Experimental Results

[0065] The effects of the above four application methods on Polygonatum cultivation were compared. The experimental results regarding Polygonatum yield, polysaccharide content in rhizomes, and selenium content are shown in Table 2.

[0066] Table 2 Comparison of Polygonatum yield, rhizome polysaccharide, and Se content after application of different selenium fertilizer solutions.

[0067] Solution type Polygonatum yield (kg / mu) Polysaccharide content (%) Selenium content (mg / kg) Selenium fertilizer application 1 1814 13.56 0.1296 Selenium fertilizer application 2 2048 14.40 0.1452 Selenium fertilizer application 3 2327 16.61 0.1731 No selenium fertilizer applied 1652 9.83 0.0878

[0068] By scientifically and rationally determining the application method of selenium fertilizer, the yield of Polygonatum increased by 9.81-40.86%, the content of polysaccharides in roots and stems increased by 37.95-68.97%, and the selenium content increased by 47.61-97.15% after root application and foliar spraying of selenium fertilizer.

[0069] In summary, through years of multi-location field trials, the rational application of selenium significantly increased the polysaccharide content in the rhizomes of Polygonatum odoratum, as well as the selenium content in the rhizomes. This not only provides a new way for the human body to supplement selenium, but also improves the quality of Polygonatum odoratum and helps to enhance its medicinal efficacy.

[0070] It should be noted that although the above embodiments have been described herein, this does not limit the scope of patent protection for this invention. Therefore, any changes and modifications made to the embodiments described herein based on the innovative concept of this invention, or any equivalent structural or procedural transformations made using the content of this specification, directly or indirectly applying the above technical solutions to other related technical fields, are all included within the scope of patent protection for this invention.

Claims

1. A method for increasing the polysaccharide content of Polygonatum sibiricum, characterized in that: The method involves applying selenium fertilizer to the leaves of *Polygonatum sibiricum* 1-2 times via foliar spraying during April-June of the first, second, and third years of cultivation. The foliar spraying method involves evenly spraying the selenium fertilizer solution onto both the upper and lower surfaces of the leaves, using a dosage of 0.4-1.0 g / L. L / plant of Polygonatum sibiricum; In September-October of the third year of Polygonatum sibiricum planting, apply selenium fertilizer to the soil of the planted Polygonatum sibiricum 1-2 times by root application. The root application method is to lightly scrape the topsoil 2-5cm and evenly spray the selenium fertilizer solution within a 5-15cm range around the rhizome. The amount of selenium fertilizer is 0.2-0.8L / plant of Polygonatum sibiricum. The fruit can be harvested after the stems have matured and fallen over in the same year. The selenium fertilizer is a compound of sodium selenite and D-galacturonic acid to form a solution with a selenium concentration of 10-200mg / L and a D-galacturonic acid concentration of 10-200mg / L. After stabilizing for 2-8 hours, add galactose at a mass concentration of 0.1-1%, stabilize for 1-2 hours, and then add glucose at a mass concentration of 0.5-8%, stabilize for 1-2 hours.

2. The method for increasing the polysaccharide content of Polygonatum sibiricum according to claim 1, characterized in that, The specific steps are as follows: Site selection: Choose an open area under the forest or forest edge at an altitude of 250m-1000m, with a canopy cover of 0.5-0.6 and a slope of <25°; Land preparation: Apply 1000-1500 kg / mu of well-rotted farmyard manure and 20-25 kg / mu of calcium magnesium phosphate as base fertilizer, then deep plow in horizontal strips 20-30 cm along the contour lines, harrow finely, and mix the fertilizer and soil thoroughly. Planting: Rhizome of Polygonatum is planted in winter, from October to November. Rhizome seedlings and seedlings are planted in early spring after they emerge, with a plant spacing of 30-40cm. Selenium fertilizer preparation: Sodium selenite, galactose, D-galacturonic acid and glucose are mixed into a solution; Selenium fertilizer application: In the first, second and third years of planting, apply selenium fertilizer to the leaves of Polygonatum 1-2 times by foliar spraying from April to June each year; in the third year of planting, apply selenium fertilizer to the soil of Polygonatum 1-2 times by root application from October to December. Harvesting: In the third year of planting, after the fruit is ripe and the stems have fallen over, the underground rhizomes are dug up.

3. The method for increasing the polysaccharide content of Polygonatum sibiricum according to claim 2, characterized in that: The soil in the area should be red or yellow soil with a pH of 5.5-6.5, and the soil texture should be loam, clay loam, or light sandy loam.