JP2022024682A - Method for cultivating cassava and plant vitalizer for cassava cultivation - Google Patents

Abstract

The present invention provides a method for improving the yield of cassava crops. The present invention relates to a method for cultivating cassava, the method comprising administering a plant vitalizing agent containing an exogenous elicitor and an endogenous elicitor to a seedling at least once.

Description

The present invention relates to a method for cultivating cassava using an exogenous elicitor and an endogenous elicitor, and a plant vitalizing agent for cultivating cassava.

The yield of plants decreases due to abiotic stress such as sunshine hours, temperature and rainfall, and biological stress such as pests. For example, cassava prefers abundant solar radiation and well-drained land, requires a cultivation temperature of 20 to 40 ° C, and a temperature of at least 15 ° C or higher, and if it falls below this range, growth will be poor. In addition, under excessive humidity conditions, adverse effects such as susceptibility to disease occur. Various fertilizers and pesticides have been used so far, especially to increase the yield of agricultural crops. Fertilizer is a nutrient source required for plant growth, but it does not have the function of relieving stress. Pesticides directly exterminate pests that parasitize plants and eliminate biological stress, but when pesticides are used, although their safety has been sufficiently confirmed, the effects on the human body and the environment due to overdose. In particular, pesticides and other chemicals produced by the chemical synthesis method may remain in the soil for a long period of time once sprayed, and if possible, other methods may be used to make them resistant to biological stress. It was desired. For this reason, in recent years, in addition to these, the use of biostimulants as substances that are safe for both the human body and the environment has attracted attention.

"Biostimulant" is also called "biological stimulant" or "plant vitalizer", contains any substance group / microorganism, and is in a natural state when applied to a plant or its root system. By stimulating a series of processes that are also occurring in the crop body, it is possible to improve nutrient absorption, fertilization efficiency, stress tolerance, and quality improvement, against pests. Those that do not show direct action and are therefore not classified as any insecticidal or bactericidal agent. That is, it refers to a substance (including microorganisms) that exists in nature, not a plant hormone or a nutrient, but stimulates the vitality of a plant and promotes its growth even in a very small amount. It is said that the application of biostimulant to plants enhances the nutrient absorption and nutrient utilization rate of plants, promotes their growth, and improves the yield and quality of crops. Agricultural biostimulants include a variety of formulations such as compounds, substances and other products applied to plants or soils to control and enhance the physiological processes of crops. Biostimulants act on plant physiology through a pathway different from nutrients to improve crop vitality, yield, quality and post-harvest shelf life.
Thus, biostimulants can stimulate the plant's inherent abilities and promote its growth without the problems of conventional pesticides and fertilizers.

As related to such biostimulants, so far, a plant vitalizing agent (Patent Document 1) in which chitin oligosaccharide and chitosan having antibacterial activity are combined, oligosaccharide and plant extract component are blended in vinegar. Plants using a plant vitalizer (Patent Document 2), a plant growth promoter containing cellulose (Patent Document 3), a plant growth regulator containing a hexoflanose derivative (Patent Document 4), and low-molecular-weight chitin and chitosan. (Patent Document 5) and a fertilizer containing chitin and / or chitosan (Patent Document 6) have been reported.

Japanese Unexamined Patent Publication No. 9-143013 Japanese Unexamined Patent Publication No. 2001-64112 Japanese Unexamined Patent Publication No. 2002-114610. Japanese Unexamined Patent Publication No. 2013-151438 JP-A-2015-48436 JP-A-2017-95352 International Publication No. 2017/10467

However, in the cultivation of plants, no study has been made so far to enhance the expression of the effect by adjusting the method of giving the plant vitalizer according to the plant species. In particular, how to give a plant vitalizer suitable for cassava was not known.

The present invention has been made in view of the above circumstances, and in the cultivation of cassava, a method of giving a plant vitalizing agent has been enthusiastically studied. As a result, it was found that the yield of the harvested product was remarkably improved by giving the seedlings of cassava a plant vitalizing agent containing an exogenous elicitor and an endogenous elicitor, and completed the present invention.

That is, the present invention includes the following [1] to [20].
[1] A method for cultivating cassava, which comprises giving seedlings at least once a plant vitalizing agent containing an exogenous elicitor and an endogenous elicitor.
[2] The method for cultivating cassava according to [1], which comprises giving the plant vitalizing agent to seedlings 2 to 15 days after germination at least once.
[3] The method for cultivating cassava according to [1] or [2], which comprises giving the plant vitalizing agent to the plant body after the seedling stage at least once.
[4] The above-mentioned one of [1] to [3], wherein the exogenous elicitor is a chitin oligosaccharide, and the endogenous elicitor is at least one oligosaccharide selected from a cellooligosaccharide and a xylooligosaccharide. How to grow cassava.
[5] The method for cultivating cassava according to any one of [1] to [4], wherein the mass ratio of the exogenous elicitor to the endogenous elicitor in the plant vitalizing agent is 0.1 to 5.
[6] The method for cultivating cassava according to any one of [1] to [5], which comprises xylooligosaccharide as the endogenous elicitor.
[7] The method for cultivating cassava according to [6], which comprises both sero-oligosaccharide and xylooligosaccharide as the endogenous elicitor.
[8] The method for cultivating cassava according to [7], wherein the mass ratio of the cellooligosaccharide to the xylooligosaccharide in the plant vitalizing agent is 0.2 to 5.
[9] Described in any one of [1] to [8], wherein the plant vitalizer is given to a plant at a concentration such that the total content of the exogenous elicitor and the endogenous elicitor is 0.1 to 500 mass ppm. How to grow cassava.
[10] The method for cultivating cassava according to any one of [1] to [9], wherein the plant vitalizer is given to a plant by foliar spraying.
[11] A plant revitalizing agent containing exogenous elicitor and endogenous elicitor used in the cultivation of cassava, which is applied to seedlings at least once.
[12] The plant vitalizer according to [11], which is applied at least once to seedlings 2 to 15 days after germination.
[13] The plant vitalizing agent according to [11] or [12], which is further applied to the plant body after the seedling stage at least once.
[14] The above-mentioned one of [11] to [13], wherein the exogenous elicitor is a chitin oligosaccharide, and the endogenous elicitor is at least one oligosaccharide selected from a cellooligosaccharide and a xylooligosaccharide. Plant vitalizer.
[15] The plant vitalizer according to any one of [11] to [14], wherein the mass ratio of the exogenous elicitor to the endogenous elicitor in the plant vitalizer is 0.1 to 5.
[16] The plant vitalizing agent according to any one of [11] to [15], which comprises xylooligosaccharide as the endogenous elicitor.
[17] The plant vitalizing agent according to [16], which comprises both cellooligosaccharide and xylooligosaccharide as the endogenous elicitor.
[18] The plant vitalizing agent according to [17], wherein the mass ratio of the cellooligosaccharide to the xylooligosaccharide in the plant vitalizing agent is 0.2 to 5.
[19] The plant vitalizing agent according to any one of [11] to [18], which is applied to a plant at a concentration such that the total content of the exogenous elicitor and the endogenous elicitor is 0.1 to 500 mass ppm. ..
[20] The plant vitalizing agent according to any one of [11] to [19], which is applied to a plant by foliar spraying.

In the method for cultivating cassava of the present invention, the yield of the harvested product can be improved by feeding the seedlings of cassava with a plant vitalizing agent containing an exogenous elicitor and an endogenous elicitor.

Hereinafter, embodiments of the present invention will be described. The embodiments described below show typical examples of the present invention, and are not limited thereto.

The method for cultivating cassava of the present embodiment includes feeding a plant energizing agent containing an exogenous elicitor and an endogenous elicitor to a cassava seedling. The "plant vitalizer" includes not only those having an abiotic stress-relieving effect such as temperature, light, water, and salt related to plant growth, but also those having an abiotic stress-relieving effect such as pests. ..

Elicitor is a general term for substances that induce a biological defense reaction in tissues or cultured cells of higher plants, and induces disease resistance in the immune system of plants. Plants sense elicitors with receptors present on the leaf surface and induce pathogen resistance reactions. This causes a biological defense action (immunity) in which various compounds are secreted against various pathogens. When elicitor acts on plants, defense reactions such as phytoalexin and pathogenesis-specific protein synthesis / accumulation, reactive oxygen species production, active nitrogen production, hypersensitive reactive cell death, and gene expression changes are induced, and these reactions induce defense reactions. Plants are thought to protect themselves from pathogens and increase disease resistance.
Phytoalexin is an antibacterial compound synthesized and accumulated in a plant by the action of elicitor, and the antibacterial compound produced differs depending on the plant species. Typical phytoalexins include flavonoids, terpenoids, fatty acid derivatives and the like. Reactive oxygen has the effect of killing pathogenic microorganisms, and active oxygen and active nitrogen function as signals to trigger various defense reactions alone or in cooperation. Disease resistance due to such an elicitor effect is expected to be used in agriculture because it enhances resistance to a wide range of diseases.

[Exogeny Elicitor]
As used herein, the term "exogenous elicitor" means an elicitor of a component derived from a biological substance other than a plant, such as a fungus, an insect, or a shellfish, and is not particularly limited as long as it has an elicitor effect, but is typically not limited. , Chitin, chitosan, and their oligosaccharides, various biomolecules derived from insects, and the like.
The plant vitalizer used in the method for cultivating cassava of the present embodiment preferably contains chitin oligosaccharide as an exogenous elicitor.

The chitin oligosaccharide contains a partially deacetylated chitosan oligosaccharide and is an oligosaccharide in which several N-acetylglucosamines are linked. Generally, it is obtained by hydrolyzing chitin derived from shellfish or the like. Also referred to as oligo-N-acetylglucosamine.
That is, the chitin oligosaccharide is obtained by chemically or enzymatically partially hydrolyzing chitin prepared by a conventional method from the shells of crustaceans such as crabs and shrimp. Examples of chitin oligosaccharides include N-acetylchitobiose, N-acetylchitotriose, N-acetylchitotetraose, N-acetylchitopentaose, N-acetylchitohexaose, N-acetylchitoheptaose, and N-. One or more mixtures selected from acetylchitooctaose and the like are preferably used. Among these, N-acetylchitopentaose, N-acetylchitohexaose, and N-acetylchitoheptaose have a particularly high elicitor effect.

なお、式中のアセチル基（－ＣＯＣＨ₃）が一部脱落して、－ＮＨＣＯＣＨ₃が－ＮＨ₂になっているものも含まれる。 The chitin oligosaccharide used in this embodiment is particularly preferably one having the following chemical structure.

It should be noted that some of the acetyl groups (-COCH ₃ ) in the formula have been removed to make -NHCOCH ₃ -NH ₂ .

[Internal Elicitor]
As used herein, the term "endogenous elicitor" means an elicitor of a plant-derived substance, and is not particularly limited as long as it has an elicitor effect, but typically, cellulose, xylan and their oligosaccharides produced from plants. And so on.
The plant vitalizer used in the method for cultivating cassava of the present embodiment preferably contains at least one oligosaccharide selected from cellooligosaccharides and xylooligosaccharides as an endogenous elicitor.

Cellooligosaccharides are oligosaccharides in which multiple glucoses are polymerized by β-glycosidic bonds, and have recently been found to have functionality such as moisturizing properties, stickiness suppression, taste-imparting, starch aging reduction, and protein denaturation suppression. , Expected to be used in the food and feed fields. In particular, sero-oligosaccharides having a glucose polymerization degree of 3 or more are expected to have higher functionality in terms of increasing the above-mentioned functionality and imparting new functionality. Cellooligosaccharides currently industrially used are produced by an enzymatic reaction, but their main components are glucose and dimeric cellobiose, and they contain almost no oligomers higher than the trimer cellobiose. However, in recent years, in the hydrolysis reaction of vegetable biomass using a carbon catalyst, the applicants have controlled the temperature rise rate, the cooling rate, the reaction temperature, and the reaction time to carry out a hydrothermal reaction to carry out the degree of polymerization of glucose. A method for producing a cellooligosaccharide containing 3 to 6 oligomers has been reported (Patent Document 7).

The cellooligosaccharide used in this embodiment is particularly preferably one having the following chemical structure.

Xylooligosaccharides are oligosaccharides in which several xyloses are polymerized by β-glycosidic bonds, and are generally obtained by hydrolysis of xylan, which is the main component of hemicellulose, and are mainly sold for food use.

The xylooligosaccharide used in this embodiment is particularly preferably one having the following chemical structure.

[Plant vitality agent]
The plant vitalizer used in the method for cultivating cassava of the present embodiment contains at least the exogenous elicitor and the endogenous elicitor as active ingredients. The mass ratio of the exogenous elicitor to the endogenous elicitor in the plant vitalizer (ie, exogenous elicitor content / endogenous elicitor content) is preferably 0.1 to 5, more preferably. It is 0.2 to 2, and more preferably 0.3 to 0.6.

Plant energizers more preferably contain xylooligosaccharides as endogenous elicitors, and optimally contain both cellooligosaccharides and xylooligosaccharides. The mass ratio of the cellooligosaccharide to the xylooligosaccharide in the plant vitalizer (that is, the cellooligosaccharide content / xylooligosaccharide content) is preferably 0.2 to 5, more preferably 0.3 to 3. It is more preferably 0.4 to 1.2.

When the plant vitalizer contains chitin oligosaccharides as exogenous elicitors and both cellooligosaccharides and xylooligosaccharides as endogenous elicitors, the ratio of each oligosaccharide to the total content of chitin oligosaccharides, cellooligosaccharides and xylooligosaccharides is , Chitin oligosaccharides are preferably 10 to 50% by mass, cellooligosaccharides are preferably 10 to 50% by mass, and xylooligosaccharides are preferably 10 to 60% by mass. The ratio of each oligosaccharide is more preferably 20 to 40% by mass of chitin oligosaccharide, 20 to 40% by mass of cellooligosaccharide, and 20 to 55% by mass of xylooligosaccharide.

The plant vitalizer may further contain other components other than the active ingredients exogenous elicitor and endogenous elicitor, such as preservatives, spreading agents, anti-precipitants, thickeners, excipients and solvents. Examples of the preservative include potassium sorbate, paraoxybenzoic acid ester, benzoin, sodium dehydroacetate, hinokitiol, phenoxyethanol, polyaminopropyl biguanide, polylysine and the like. The spreading agent is a viscous liquid containing a surfactant as a main component, and is not particularly limited as long as it can be used as a spreading agent for plant vitalizing agents. For example, polyoxyethylene nonylphenyl ether, sorbitan fatty acid ester, and polyoxy. Examples thereof include ethylene hextan fatty acid ester. Examples of the anti-precipitation agent include polyphosphoric acid or salts of polyphosphoric acid, polycarboxylic acid type polymer surfactants, and the like. Examples of the thickener include water-soluble polymers such as carboxymethyl cellulose (CMC), polyacrylamide, and starch, molasses, alcohol fermentation concentrated waste liquid, amino acid fermentation concentrated waste liquid, and the like. Examples of the excipient include lactose and starch. The solvent is used for the purpose of diluting the active ingredient to an appropriate concentration to make it liquid, and for the purpose of facilitating spraying on plants. Water is preferable as the solvent.

The plant vitalizing agent used in the method for cultivating cassava of the present embodiment may be powdery, granular, liquid or the like, but in general, it is preferably liquid that is easy to spray. When a liquid plant energizer is used, the concentration of the active ingredient in the plant energizer at the time of spraying on the plant is preferably 0.1 to 500 mass ppm, more preferably 0.5 to 200 mass ppm. More preferably, it is 1 to 100 mass ppm. The concentration of the active ingredient in the plant vitalizer is the total content of the exogenous elicitor and the endogenous elicitor in the plant vitalizer. When the spraying concentration is 0.1% by mass or more, the effect as a plant vitalizing agent is efficiently exhibited. When the spraying concentration is 500 mass ppm or less, disease resistance can be developed without causing plant growth inhibition.

As the plant vitalizer, a commercially available product whose active ingredient concentration is prepared in advance to the above concentration may be used, but usually, a plant vitalizer stock solution containing a high concentration of exogenous elicitor and endogenous elicitor is diluted with water. And use it. When the plant vitalizer stock solution is diluted (for example, diluted 1000 times) and used, the total content of exogenous elicitor and endogenous elicitor in the plant vitalizer stock solution is preferably 0.05 to 10% by mass. It is more preferably 0.1 to 8% by mass, and even more preferably 0.5 to 6% by mass.

[Cassava]
The types of cassava cultivated by the cultivation method of the present embodiment include varieties such as bittersweet varieties and sweet varieties, and are not particularly limited.

[Cultivation method]
The cultivation form of cassava is not particularly limited, and examples thereof include sowing cultivation and cutting cultivation, but cutting cultivation is preferable.

As an example, in the case of cuttings cultivation, the following methods can be mentioned.
It is preferable to select a subtropical and tropical field that does not become over-humidified with an average temperature of 20 to 35 ° C and plant it from March to May. One week before planting, the field is cultivated deeply by applying a modest amount of fertilizer, about 30 to 50% of the specified amount, to make ridges. Since drainage is important for cassava cultivation, the ridge height is preferably as high as 20 to 30 cm. The ridge width is preferably 80 to 100 cm, and the ridge spacing is preferably about 90 to 120 cm. A stem for cuttings cut to about 8 to 15 cm is planted in a hole dug at a depth of about 80 to 120 cm and a depth of about 8 to 15 cm, covered with soil, and lightly pressed. It germinates in about one week after planting, but it is preferable to manage topdressing, soil gathering, irrigation, etc. until harvest according to the conventional farming method. 9 to 11 months after planting, the plants are removed and the root potatoes are harvested.

The method for cultivating cassava of the present embodiment includes feeding the seedlings with the plant vitalizing agent. As used herein, the term "seedling" of cassava refers to seedlings from germination to the third week.

In one embodiment, it is preferable to use the plant vitalizer at least once for seedlings 2 to 15 days after germination. It is more preferable to use the plant vitalizer at least once for seedlings 2 to 10 days after germination, and it is further preferable to use the plant vitalizer at least once for seedlings 2 to 5 days after germination. In order to obtain more fulfilling seedlings, the plant vitalizer is used at least once for the seedlings 2 to 15 days after germination, and at least once for the subsequent seedlings once every 5 to 10 days. It is particularly preferred to use.

As another embodiment of the method for cultivating cassava of the present embodiment, it is preferable to further give the plant vitalizing agent to the plant body after the seedling stage. In the present specification, the "plant body after the seedling stage" of cassava means a plant body after the period of the above "seedling", that is, a plant body after 3 weeks from germination.

In one embodiment, it is preferable to use the plant vitalizer at least once on the plant after the seedling stage. It is more preferable to use it 5 to 12 times at a rate of once every 2 to 4 weeks until about 8 months after planting.

(Application of plant vitalizer)
The application of the plant vitalizer to cassava can be carried out by a method customary in the art, and the method of spraying is not particularly limited. It may be either a method of spraying in soil, a method of blending with fertilizer or the like and spraying in a culture group or soil. When blended in fertilizer, the types of fertilizer include chemical fertilizers containing nitrogen, phosphoric acid, and potassium, oil residue, fish residue, bone powder, seaweed powder, amino acids, sugars, and organic fertilizers such as vitamins. Not limited. As a spraying method, it is particularly preferable to carry out by foliar spraying in order to effectively express the elicitor activity. Foliar spraying can be performed by techniques customary in the art, such as power sprayers, shoulder sprayers, broadcasters, sprayers, manned or unmanned helicopters, fumes, hand sprays and the like.

The amount of the plant vitalizing agent sprayed is preferably such that the amount of the active ingredient sprayed per 1 cm ² of the leaf surface is 0.1 ng to 100 ng, and the amount of the active ingredient sprayed per 1 cm ² of the leaf surface is 1 ng or more. It is more preferable that the amount is 20 ng. In an actual field, it is difficult to selectively spray only on the leaf surface and to attach all the sprayed material to the leaf surface, so 0.01 g to 20 g of active ingredient per 100 m ² of cultivated area is used. It is preferable to dilute the concentration in the plant vitalizer to 1% by mass to 100% by mass and spray it evenly on the plant body. More preferably, it is preferable to dilute the active ingredient of 0.1 g to 10 g per 100 m ² of the cultivated area so that the concentration in the plant vitalizer is 10 mass ppm to 500 mass ppm.

In the cassava cultivation method of the present embodiment, it is preferable that soil management is carried out by a conventional farming method.

(Effect of plant vitalizer)
The method for cultivating cassava of the present embodiment includes feeding a plant energizing agent containing an exogenous elicitor and an endogenous elicitor to a cassava seedling. In addition, it is preferable to continue to give a plant energizing agent containing an exogenous elicitor and an endogenous elicitor to the plant body after the seedling stage of cassava. The reason why the effect is exhibited by giving the plant vitalizer having such a composition at this time is not completely elucidated. By giving an exogenous elicitor (for example, derived from chitin oligosaccharide), the plant is imparted with disease resistance derived from a herbivore, etc., but it is considered that growth inhibition occurs if it acts excessively. On the other hand, by giving endogenous elicitors (for example, derived from cellooligosaccharides and xylooligosaccharides), plants are made to recognize their own cell damage and crushing components (DAMPs: damage-associated molecular patterns), and acquire immunity and cells. It can be expected to promote growth by itself for restoration. In the method for cultivating cassava of the present embodiment, a tough seedling that has been imparted with disease resistance while suppressing growth inhibition is obtained by giving a plant vitalizing agent containing an exogenous elicitor and an endogenous elicitor, especially in the early seedling stage. It is thought that it can be nurtured. By continuing to use the plant vitalizer on the strong plants raised in this way, the growth promoting action of the endogenous elicitor is utilized without being strongly affected by the growth inhibitory action of the exogenous elicitor, and finally. It seems that a high growth effect can be realized in which both act in a complementary manner. Therefore, when cultivating cassava, by giving the plant vitalizer at least once to the seedlings and at least once to the plants after the seedling stage, the plants grow strongly and the yield of the harvest is improved. Can be estimated.

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.

[1. Preparation of oligosaccharides]
(1) Chitin oligosaccharide 10 g of chitin powder (manufactured by Wako Pure Chemical Industries, Ltd., purified chitin) was dispersed in 30 mL of water containing 1.2 g of 85% phosphoric acid (manufactured by Wako Pure Chemical Industries, Ltd., a special grade reagent), and then the powder was dried under reduced pressure. It was placed in an alumina pot having a capacity of 250 mL together with 100 g of alumina balls having a diameter of 5 mm, set in a planetary ball mill (PULVERISETTE 6 manufactured by Fritsch), and treated continuously at 500 rpm for 6 hours to obtain a reactant. The temperature was started at room temperature, and the temperature rise due to shear heat generation was left to the discretion.
Subsequently, the slurry liquid in which the reaction product was suspended in water and neutralized with calcium hydroxide was filtered through a Nutche filter using 5B filter paper, and the recovered filtrate was freeze-dried to obtain chitin oligosaccharide powder. did.

(2) Cellooligosaccharide Cotton linter pulp (Toko Kosen Co., Ltd., cellulose content 97%) 271 g (moisture content 1.8%, dry mass 266 g) using a food blender (model number: HBF500S, manufactured by Hamilton Beach). It was mixed with 38 g of 85 mass% phosphoric acid (special grade reagent manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) to obtain 309 g of reaction raw material (moisture content 3.4%, phosphoric acid content 10.4%).
Subsequently, 309 g of the reaction raw material was put into a vibration mill (device name: MB-1 type, manufactured by Chuo Kakoki Co., Ltd., pot size 5 L) together with 13 kg of φ3/4 inch carbon steel balls, and the total amplitude was 8 mm and the frequency. A hydrolysis reaction was carried out by dry pulverization for 24 hours under the conditions of 16.2 Hz and a jacket circulating water temperature of 75 ° C., and then the reaction powder was recovered.
10 g of this reaction powder and 90 g of ion-exchanged water were placed in a 200 L beaker and stirred at 25 ° C. for 1 hour using a magnetic stirrer to obtain an extract of a cellulose hydrolyzate.
Subsequently, 1.3 g of a 40 mass% calcium hydroxide aqueous solution was added to the extract, and the supernatant was recovered from the neutralized solution prepared by stirring at 25 ° C. for 1 hour using a magnetic stirrer by a centrifuge. Then, it was freeze-dried to obtain a cellooligosaccharide powder.

(3) Xylooligosaccharide Acremonium Cellulolyticti
cus) TN strain (FERM P-18508) in a liquid medium (Abisel 50 g / L, KH ₂ O ₄ 24 g / L, ammonium sulfate 5 g / L, potassium tartrate 1 / 2H ₂ O 4.7 g / L, urea 4 g / L) , _Tween80 1g / L, _{Л4.7H 2} O _1.2g / L, ZnSO _{4.7H 2} O 10mg / L, MnSO 4.5H ₂ O 10mg / L, CuSO 4.5H ₂ O 10mg / L) 100mL In a 500 mL flask containing the mixture, the cells were shake-cultured at 30 ° C. for 6 days. 5 g of corn cob powder was suspended in 50 mL of the centrifugal supernatant of the obtained culture solution, and the mixture was stirred and reacted at 50 ° C. and 72 hours. The obtained centrifugal supernatant of the reaction solution was freeze-dried to obtain the bulk powder of xylooligosaccharide.

[2. Cultivation of cassava]
(1) Preparation of plant vitalizer [1. Preparation of oligosaccharides] so that each oligosaccharide is 1000 times the concentration of the active ingredient (mass ppm) in the plant vitalizers shown in Examples 1 to 11 and Comparative Examples 1 to 5 in Table 1. Stirrer was stirred at each composition ratio, dissolved in water, and then sterilized with a 0.45 μm filter to obtain a plant vitalizer stock solution. This undiluted solution was diluted 1000-fold with water and used in the following cultivation test. Hereinafter, the plant vitalizing agent after diluting the undiluted solution 1000 times may be referred to as "plant vitalizing agent diluted solution". The composition ratio of each oligosaccharide in the table represents mass%.

(2) Cultivation test 1 (Examples 1 to 11, Comparative Examples 1 to 5)
The field cultivation of cassava was carried out in a greenhouse using a field of 240 m ² in total. Two weeks before the planting schedule, the field was cultivated and mixed with humus. In the field prepared in the middle of March, ridges with a ridge width of 80 cm, a ridge of 100 cm, and a ridge height of 25 cm are made, and cassava (sweet seed) cuttings (around 10 cm in length) are planted at 100 cm intervals to a depth of 10 to 12 cm. rice field. After the soil was covered, the soil was lightly suppressed, and when the water was sufficiently sprinkled, germination occurred sequentially after 8 to 10 days. The conventional farming method was carried out by dividing them into 20 plots of 5 shares / ward each.
The germinated cassava seedlings and the plants after the seedling stage were sprayed with a diluted solution of plant vitalizer to the extent that the leaves and soil were moistened under the conditions shown in Table 1.
Prepare an aqueous solution (diluted plant vitalizer) prepared to the concentration of the active ingredient of the plant vitalizer under each condition at 1 kg / plot until the seedling stage and 2 months after planting, and 2 kg / plot after 3 months after planting, and watering can. The operation of foliar spraying and irrigation of the soil near the root was performed as shown in Table 1. Harvesting was carried out 10 months after planting, and the average yield of each plot (5 strains) was measured and compared under each condition.
The yield was measured by cutting the potatoes (edible parts) at the roots of the plants and measuring the average weight per plant. The test results are shown in Table 1.

[3. Cultivation of Brassicaceae plants (Reference Examples 1-3)]
A test was conducted using Komatsuna, a Brassicaceae.
In the field where the compost was plowed and cultivated, the rows were ridged with a space of about 15 to 20 cm, and the seeds of Komatsuna (Inamura seeds) were sown at intervals of 1 to 1.5 cm and lightly covered with soil. After squeezing, it was thoroughly irrigated. The germinated Japanese mustard spinach was thinned out as appropriate, and the diluted solution of plant vitalizer was sprayed to the extent that it was moistened on the leaf surface and soil under the conditions shown in Table 2. Harvesting was carried out when the plant height reached 20 to 25 cm, and the harvest weight per plant was compared with respect to 20 seedlings. The test results are shown in Table 2.

From the results in Table 1, it was confirmed that in the cultivation of cassava, the yield was significantly improved by using a plant vitalizer containing both exogenous elicitor and endogenous elicitor for seedlings. On the other hand, from the results in Table 2, in the cultivation of Komatsuna, which is a Brassicaceae plant, even if a plant vitalizer containing both exogenous elicitor and endogenous elicitor is used for seedlings in addition to the pre-harvest growth period. No significant improvement in weight per share was confirmed.

Claims (20)

A method for cultivating cassava comprising feeding seedlings at least once with a plant energizer comprising exogenous elicitor and endogenous elicitor. The method for cultivating cassava according to claim 1, wherein the plant vitalizer is given to the seedlings 2 to 15 days after germination at least once. The method for cultivating cassava according to claim 1 or 2, wherein the plant vitalizing agent is further applied to the plant body after the seedling stage at least once. Cultivation of cassava according to any one of claims 1 to 3, wherein the exogenous elicitor is a chitin oligosaccharide, and the endogenous elicitor is at least one oligosaccharide selected from a cellooligosaccharide and a xylooligosaccharide. Method. The method for cultivating cassava according to any one of claims 1 to 4, wherein the mass ratio of the exogenous elicitor to the endogenous elicitor in the plant vitalizing agent is 0.1 to 5. The method for cultivating cassava according to any one of claims 1 to 5, which comprises xylooligosaccharide as the endogenous elicitor. The method for cultivating cassava according to claim 6, which comprises both sero-oligosaccharide and xylooligosaccharide as the endogenous elicitor. The method for cultivating cassava according to claim 7, wherein the mass ratio of the cellooligosaccharide to the xylooligosaccharide in the plant vitalizing agent is 0.2 to 5. The cassava according to any one of claims 1 to 8, wherein the plant vitalizer is given to the plant at a concentration such that the total content of the exogenous elicitor and the endogenous elicitor is 0.1 to 500 mass ppm. Cultivation method. The method for cultivating cassava according to any one of claims 1 to 9, wherein the plant vitalizer is given to a plant by foliar spraying. A plant revitalizer containing exogenous elicitor and endogenous elicitor used in the cultivation of cassava, which is applied to seedlings at least once. The plant vitalizer according to claim 11, which is applied at least once to seedlings 2 to 15 days after germination. The plant vitalizer according to claim 11 or 12, further applied at least once to the plant after the seedling stage. The plant vitalizing agent according to any one of claims 11 to 13, wherein the exogenous elicitor is a chitin oligosaccharide, and the endogenous elicitor is at least one oligosaccharide selected from a cellooligosaccharide and a xylooligosaccharide. .. The plant vitalizer according to any one of claims 11 to 14, wherein the mass ratio of the exogenous elicitor to the endogenous elicitor in the plant vitalizer is 0.1 to 5. The plant vitalizing agent according to any one of claims 11 to 15, which comprises xylooligosaccharide as the endogenous elicitor. The plant vitalizing agent according to claim 16, which comprises both cellooligosaccharide and xylooligosaccharide as the endogenous elicitor. The plant vitalizing agent according to claim 17, wherein the mass ratio of the cellooligosaccharide to the xylooligosaccharide in the plant vitalizing agent is 0.2 to 5. The plant vitalizer according to any one of claims 11 to 18, which is applied to a plant at a concentration such that the total content of the exogenous elicitor and the endogenous elicitor is 0.1 to 500 mass ppm. The plant vitalizer according to any one of claims 11 to 19, which is applied to plants by foliar spraying.