JPH0433408B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention promotes plant growth by applying alginic acid oligosaccharide to plants or soil,
The present invention provides a method that enables efficient production of agricultural products. [Conventional techniques and their problems] It is an important issue in agricultural production to increase yield by promoting the growth of agricultural crops, increasing the yield per unit area, and increasing the number of plantings. Plant hormones such as gibberellins and auxins have been reported as plant growth-promoting substances, but the effects of these plant hormones are multifaceted and have many effects on plants at the same time. Even if one effect is beneficial, another effect may be harmful, and its practical use is limited. On the other hand, in recent years, it has been reported that oligosaccharides obtained through the decomposition of polysaccharides that constitute the cell walls of plants play an important role as regulators of the plant's own biological defense responses and induction of differentiation. I've come to feel that way. For example, when applied to soybean, oligogalacturonic acid prepared from plant cell walls promotes the synthesis of certain antibacterial substances (phytoalexins) and enhances resistance to pathogenic bacteria; It has been reported that oligosaccharides (xylo-oligosaccharides) produced by peas have the effect of suppressing the growth-promoting effect of auxin on pea sprouting. The actions of such oligosaccharides are different from those of plant hormones, and their actions are said to be specific rather than pleiotropic. [Means for Solving the Problems] The purpose of the present invention is to discover sugars that promote the growth of agricultural crops from among various oligosaccharides, apply these oligosaccharides to agricultural production, and improve the efficiency of agricultural production. The goal is to make the world more popular. In order to achieve the above object, the present inventors extensively searched for oligosaccharides that have the effect of promoting the growth of agricultural crops, and obtained oligosaccharides obtained by decomposing alginic acid (hereinafter referred to as alginic acid oligosaccharides).
The present invention has been completed based on the new discovery that this has the effect of promoting the growth of roots and above-ground parts of agricultural crops.
That is, the present invention provides (a) an oligosaccharide having a degree of polymerization of 2 to 20 and composed only of guluronic acid, and (b) a degree of polymerization of 2 to 20.
Oligosaccharides composed only of mannuronic acid and
(C) An oligosaccharide obtained by decomposing alginic acid, which has a degree of polymerization of 2 to 20 and is a mixture of oligosaccharides composed of guluronic acid and mannuronic acid, or the oligosaccharide.
This is a method of cultivating agricultural products characterized by using crops obtained by heat treatment for 15 minutes to 180 minutes under conditions of pH 1 to 3 and 100 to 130°C. The constituent sugars of alginic acid are mannuronic acid and guluronic acid, and the oligosaccharides obtained by decomposing these polysaccharides have a completely different chemical structure from the previously reported oligogalacturonic acids and xylooligosaccharides. It is also a new fact that oligosaccharides have the effect of promoting the growth of roots and above-ground parts of agricultural crops. In the present invention, alginate oligosaccharide is defined as follows. An oligosaccharide composition obtained by decomposing alginic acid, sodium alginate, and polysaccharides originating from microorganisms and algae such as kelp containing alginic acid with an enzyme such as alginate lyase, or by hydrolyzing with an acid such as hydrochloric acid. The main constituent sugar components of sugar are guluronic acid and mannuronic acid. It is a mixture of oligosaccharides having a degree of polymerization of 2 to 20 and composed of only guluronic acid, only mannuronic acid, or a combination of guluronic acid and mannuronic acid. Furthermore, this mixture has a pH of 1
~3. A heat-treated product obtained by heating for 15 minutes to 180 minutes under conditions of 100 to 130°C can also be used in the same manner. means. Such a composition is prepared, for example, as follows. All alginic acid-containing raw materials can be used as raw materials, including commercially available alginic acid, sodium alginate, alginic acid-containing seaweeds such as kelp, kajime, lesonia, and dulberia, and alginic acid-like polysaccharides produced by microorganisms such as Pseudomonas. can. As a means of decomposing alginic acid, a method of hydrolyzing it with an acid such as hydrochloric acid or sulfuric acid, and a method of decomposing it with an enzyme such as alginate lyase can be applied. When hydrolyzing with acid, for example, add 100 parts of water to 5 parts of sodium alginate to dissolve the alginic acid, then add 3 parts of concentrated hydrochloric acid and heat at 90 to 100°C for 2 to 4 hours.
After a period of hydrolysis, the alginate oligosaccharide can be prepared by filtering, neutralizing the solution with caustic soda, and concentrating. In addition, when decomposing with alginate lyase, add 100 parts of water to 5 parts of sodium alginate to dissolve alginic acid, then
Prepare alginate oligosaccharides by adjusting the pH to the optimum pH for enzyme action, adding 100 to 4000 units of enzyme per gram of sodium alginate, and reacting for 24 to 48 hours at the optimum temperature for enzyme action. I can do it. When an abalone gastrointestinal enzyme (trade name: Avalon Acetone Powder, manufactured by Merck) is used as alginate lyase, the optimum action pH is 7 to 8 and the optimum action temperature is 20 to 35°C. Enzyme activity of alginate lyase is PH7.0, 30℃
When an enzyme is applied to a 0.2% sodium alginate solution, the enzyme power that increases the absorbance at 230 nm by 0.01 in 30 minutes is expressed as one unit. In addition, when obtaining oligosaccharides directly from seaweed,
For example, add 1,300 parts of water to 40 parts of dried kelp to bring the pH to 11, grind it with a homogenizer, treat it at 60°C for 3 hours, then bring the pH to 5.5, and add cellulase (product name: Meicelase, Meiji Seika Co., Ltd.) was added at a solid content of 0.5%, and after reacting at 40℃ for 20 hours, the pH was adjusted to 7.0.
1000% alginate lyase per 1g of solid content.
Alginate oligosaccharides can be produced directly from kelp by adding units and reacting at 30°C for 48 hours. The alginic acid oligosaccharide obtained in this way has mannuronic acid and guluronic acid as its main sugar components, and contains only guluronic acid with a degree of polymerization of 2 to 20, only mannuronic acid, or guluronic acid and mannuronic acid. It is a mixture containing oligosaccharides composed of a combination of acids. The content of alginate oligosaccharide in the decomposition product obtained as described above takes various values depending on the decomposition raw material, but for example, when prepared by an enzymatic decomposition method using sodium alginate as the raw material, solid Monochu 40
Reach ~100%. In addition, when seaweed such as kelp is used as a raw material, it accounts for 10 to 25% of the solid material. The alginic acid oligosaccharide thus obtained can be applied to seeds, etc., added to soil as a 0.25 to 0.00025% aqueous solution, sprayed on leaves, and even added to liquid fertilizer for hydroponic cultivation. When applied to agricultural crops by adding and mixing with the composition, it promotes the growth of the roots and above-ground parts of the crops, resulting in improved yields. ~3, preferably PH2.0
~3.0. It has become clear that heat treatment can be further promoted by performing heat treatment for 15 to 180 minutes at a temperature of 100 to 120°C. It should be noted that undecomposed alginic acid or sodium alginate had no growth-promoting effect on agricultural crops, as shown in Example 1 below, for example. [Example] Next, the present invention will be explained in detail with reference to Examples. Example 1 Alginate lyase (Avalon Acetone Powder) was added to alginic acid at a rate of 4000 u/g alginic acid, and reacted at pH 7.0 and 40°C for 48 hours to prepare oligosaccharides. ℃2
Heat treatment was performed for a period of time. After heat treatment, the reaction solution
The pH was neutralized to 7.0, and the plant growth promoting effect of alginate oligosaccharides before and after heating was investigated using daikon radish. That is, 36 Kaiware radish seeds were sown in a glass container set with a synthetic resin wool mat, 70 ml of tap water was added, and the mixture was heated at 23°C.
The seeds were cultivated for 6 days (4 days in the dark and the following 2 days under irradiation conditions of 5000 lux). Alginate oligosaccharide was added at a rate of 2.5 to 0.000025% based on tap water. The results are shown in Table 1. Alginate oligosaccharide promotes the growth of both shoot and root length compared to the control plot without alginate oligosaccharide under any concentration condition, but the effect is enhanced in the PH3.0, 120℃, 2-hour heating section. There was a tendency to

[Table] The values in Table 1 are the stem and leaf lengths (cm) grown under conditions without additives such as alginate oligosaccharides.
Or, it is expressed as an index when the average value of root length (cm) is set as 100. (n=36) Example 2 Two seeds of Mitsuba (white-stem Mitsuba) were sown in a 4 cm square synthetic resin wool pine and immersed in a liquid fertilizer containing Otsuka House Fertilizer No. 1 0.15% and Otsuka House Fertilizer No. 2 0.1%. After that, they were cultivated for 10 days at 23℃ and 5,000 lux to germinate and raise seedlings, and then planted in a hydroponic cultivation device at 8,000 lux. It was cultivated for 2.5 months under the condition of 23-24℃. The experimental areas are as follows. Control group: Seedlings were raised with liquid fertilizer without addition of oligosaccharide alginate, and then cultivated with liquid fertilizer without additives. Alginate oligosaccharide added area: Alginate oligosaccharide
After raising seedlings with liquid fertilizer containing 0.025%, they were subsequently cultivated with liquid fertilizer containing 0.025% oligosaccharide alginate. In addition, alginate oligosaccharides are prepared by adding alginate lyase to a 5% sodium alginate solution (PH7.0).
Added at a rate of 4000u/g alginic acid, 40℃,
After reacting for 48 hours, the pH of the reaction solution was adjusted to 3.0 and 120
The mixture was heat-treated at ℃ for 2 hours, cooled, and then neutralized to pH 7.0. The test results are shown in Table 2. An increase in the yield of Mitsuba was observed with the addition of alginate oligosaccharide.

[Table] Example 3 1 part by weight of an aqueous solution containing 0.25% alginate oligosaccharide and 0.75% sodium alginate was sprayed onto 1 part by weight of radish seeds, dried in an air stream at 40 to 50°C, and the alginate oligosaccharide was Seed coated seeds were prepared. 50 alginic acid oligosaccharide-coated seeds thus obtained were sown in a glass container equipped with a synthetic resin wool mat, and 70 ml of tap water was added.
The plants were grown for 6 days at 23°C in the dark for 4 days and then under irradiation at 5000 lux for the next 2 days. As a control, seeds without seed coating were sown in the same manner and cultivated under the same cultivation conditions. The results are shown in Table 3.

[Table] As is clear from Table 3, when coated seeds coated with 2.5 mg of alginate oligosaccharide per gram of seeds were used, an elongation of 118% in stem and leaf length and 164% in root length was observed. Example 4 9 kg of black soil was added to a 17 cm x 60 cm x 15 cm pot, 40 seeds of Komatsuna (cultivar name: Misugi Komatsuna) were sown, and the pot was cultivated under natural conditions from June 15th to July 4th. . The experimental areas are as follows. Control group: Alginic acid oligosaccharide-free additive area: 22 g of alginic acid oligosaccharide was made into a 3.6 aqueous solution, and the entire amount was added to black soil to make soil in which 0.25% alginic acid oligosaccharide was added to the black soil, and cultivation was performed. Note that the alginate oligosaccharide prepared by the method described in Example 2 was used. The results are shown in Table 4.

[Table] A 20% increase in yield was observed by adding alginate oligosaccharide to soil. Example 5 36 corn seeds were sown per 33 m ² and cultivated for 3.5 months under natural conditions. The experimental areas are as follows. Control group: Oligosaccharide alginate untreated group Addition group: After germination, when the length of the leaves reached 8 to 12 cm, 6 g of oligosaccharide alginate was applied as a 0.05% aqueous solution around the roots. moreover,
After 1.5 months, 6 g of alginate oligosaccharide was additionally applied in the same manner. Note that the alginate oligosaccharide prepared according to the method described in Example 2 was used. The results are shown in Table 5.

[Table] A 26% increase in corn yield was observed by applying alginate oligosaccharide. Example 6 100 cucumber seeds (variety name, Lady) were sown in a tray for raising seedlings, cultivated for one week at 20 to 23°C, and then planted in three-inch pots, and the seedlings were raised for another two weeks.
The seedlings thus obtained were planted in soil at intervals of 80 cm and cultivated under natural conditions for 3 months. The experimental areas are as follows. Control group: Alginate oligosaccharide untreated and added group: Three-inch pots After planting, on the third day, alginate oligosaccharide was dissolved in 50 ml of water at a rate of 25 mg per pot and applied. Further, 50 mg of the solution was dissolved in 500 ml of water and applied additionally 3 weeks after planting. Note that alginic acid oligosaccharide was prepared in the same manner as in Example 2. The results are shown in Table 6.

〔Effect of the invention〕

By using alginic acid oligosaccharides according to the present invention, it is possible to promote the growth of useful plants and increase their yield.

Claims (1)

[Scope of Claims] 1 (a) An oligosaccharide with a degree of polymerization of 2 to 20 and composed only of guluronic acid, (b) an oligosaccharide with a degree of polymerization of 2 to 20 and composed only of mannuronic acid, and (C) Degree of polymerization is 2~
The oligosaccharide obtained by decomposing alginic acid, which is a mixture of oligosaccharides composed of guluronic acid and mannuronic acid, or the oligosaccharide at pH 1 to 3, 100
A method for cultivating agricultural products characterized by using products obtained by heat treatment for 15 minutes to 180 minutes under conditions of ~130°C. 2. The method according to claim 1, wherein an oligosaccharide obtained by decomposing alginic acid or a heat-treated product thereof is applied to seeds of agricultural crops. 3. The method according to claim 1, wherein the oligosaccharide obtained by decomposing alginic acid or a heat-treated product thereof is sprayed on the leaves of agricultural crops. 4. The method according to claim 1, in which an oligosaccharide obtained by decomposing alginic acid or a heat-treated product thereof is added to and mixed with fertilizer. 5. The method according to claim 1, wherein the oligosaccharide obtained by decomposing alginic acid or a heat-treated product thereof is mixed with soil in advance, and the soil is used. 6. The method according to claim 1, wherein an oligosaccharide obtained by decomposing alginic acid or a heat-treated product thereof is made into an aqueous solution, and the soil is sprinkled with this solution.