JPS624389B2 - - Google Patents

Description

[Detailed description of the invention]

(a) Technical Field of the Invention The present invention relates to a novel α-pyrone derivative or a salt thereof and a plant growth regulator containing the same as an active ingredient. (b) Prior Art Many compounds have been discovered and put into practical use for regulating the growth of plants, particularly grains, fruits, and vegetables. In particular, growth inhibitors such as
There are substances isolated from plants such as oxy derivatives such as benzoic acid and cinnamic acid, and phenolic compounds such as flavonoids, as well as certain aromatic compounds, terpenic alicyclic compounds, amino acids, and peptides. Pathogens or their metabolites are known. (c) Structure of the Invention The present inventors have conducted intensive research on the toxins produced by various fungi that occur on plants, their structures, and their physiologically active effects. Among the various compounds produced by this plant, we have been able to isolate some of them, elucidate their structures, and investigate their activities, which have shown that they have growth-regulating effects, such as growth-inhibiting effects, on plants. It turned out that I was doing it. The present invention has been achieved based on such knowledge, and is based on the following general formula [] [However, in the formula, R ₁ represents -CH ₂ OH or -CHO, and R ₂ represents H or -CH ₃ . ] An α-pyrone derivative represented by the above and its salt, and a plant growth regulator containing the same as an active ingredient. The pyrone derivative of the present invention is included in various compounds produced by Alternaria solani, and therefore can be isolated from its products. In order to obtain an effective and certain amount, the above-mentioned Potato Phytophthora blight bacteria may be cultured in a medium, and operations such as extraction, concentration, and crystallization from the culture solution may be performed. For example, Potato Phytophthora blight is placed in a potato decoction medium, cultured at approximately 25°C for several weeks, the resulting culture solution is extracted with chloroform, the extract is fractionated with a packed column (silica gel column), and the resulting culture solution is extracted with chloroform. It can be isolated from fractions. The present inventors fractionated the above-mentioned extract into 13 fractions and investigated the physiological activity of lettuce seeds for each fraction, and found that a certain fraction had 70% or more activity in roots and hypocotyls. It was found that it had an elongation inhibitory effect. As α-pyrone derivatives represented by the above general formula [] of the present invention, the following compounds have particularly good plant growth inhibiting activity and are preferred compounds. R ₁ R ₂ -a -CHO -H -b -CH ₂ OH -H -c -CHO -CH ₃ -d -CH ₂ OH -CH _3These compounds -a to -d are Germination inhibition and elongation inhibition were observed;
In addition, necrosis was observed on potato leaves, and -c was particularly effective in necrosis. Therefore, the compounds of the general formula [] of the present invention can be used as growth regulators, especially growth inhibitors, for various plants. The α-pyrone derivative of the present invention is conveniently represented by the above general formula [], but its tautomer is naturally included in the present invention. Particularly preferred are those having the structure of the following general formula. In order to use the compound [ ] of the present invention for the purpose of regulating plant growth, it can be used as it is on crops, etc., but depending on the place of use, purpose of use, type of target plant, etc., water etc. It may be dissolved or dispersed in a medium and sprayed, or it may be impregnated into soil. Direct application is preferred. In addition, as used in general plant growth regulators, it can be used not only in solutions but also in liquid form such as wettable powders, emulsions, oils, and suspensions; Although it is possible to use it in solid form such as granules, it is preferable to use it in solution or suspension form. When the plant growth regulator of the present invention is used in the form of a solution or suspension, its concentration can be varied over a wide range depending on the type of target plant and the situation, but is generally 1 to 100,000 ppm, preferably 5 to 100,000 ppm.
A range of 10000ppm is appropriate. The present invention will be described in detail below with reference to Examples. (d) Examples Example 1 (Culture of bacteria and separation of products) Potato summer blight (Alternaria solani) was grown in a potato decoction medium (150 c.c. of decoction was placed in a 500 c.c. Erlenmeyer flask). Inoculate the seeds in a dark place at a constant temperature of 25℃ for 25 minutes.
It was statically cultured for 1 day. One hundred bottles of this medium were prepared and cultured simultaneously under the same conditions. The resulting culture media were combined (15) and filtered through gauze to separate 760 g of bacterial cells, and the culture solution was concentrated to obtain a 1.5 concentrate. Add hydrochloric acid to this concentrate to adjust the pH to 3.5, add chloroform 5, separate the chloroform layer, and remove chloroform from the chloroform layer to obtain 2.741
g of a cloudy red oil was obtained. Add this oil (2.741g) to 120g of silica gel.
Fractionation was performed by column chromatography using (WAKOgelC-200). Benzene and ethyl acetate mixtures (9:1 and 1:
1), ethyl acetate and methanol were used. The above oily substance was fractionated into 13 fractions A to M, and the weight of each fraction was as follows. Unit is mg
It was expressed as A (80), B (19), C (171), D (41), E
(155), F (30), G (50), H (259), I
(225), J (104), K (419), L (183), M
(98), Example 2 (Measurement of germination inhibition and elongation inhibition) A 7 cm diameter filter paper (Toyo Paper) was placed in a 9 cm diameter shear dish.
No. 2), and each of the fractions A to M obtained in Example 1 above was dissolved in ethyl acetate (reagent special grade).
1 ml of it was soaked into filter paper. After air-drying, dry under reduced pressure in a desiccator to thoroughly remove the solvent, and add 3 ml of an aqueous solution (concentration 100 ppm) of surfactant (Tween 80).
Added ml. At this time, the concentration of each fraction was adjusted to be 500 ppm when dissolved in the aqueous solution of surfactant. On the other hand, as a comparative example, the above paper was impregnated with only ethyl acetate, air-dried, and then impregnated with an aqueous surfactant solution. Twelve lettuce seeds were sown in each of the shears obtained as described above, and the seeds were left in the dark at 23°C for 3 days. The germination state was observed after 24 hours, 48 hours and 72 hours, and the germination inhibition rate was calculated according to the following formula. Germination inhibition rate (%) = 100 - number of germination of reagent (average) / number of germination of control (average) The average value of the length of the hypocotyls and roots of 10 grains was determined, and the elongation inhibition rate was calculated according to the following formula. Elongation inhibition rate (%) = 100 - Sample hypocotyl (or root) length (average) / Control example hypocotyl (or root) length (average) x 100 Lettuce at 500 ppm concentration of each fraction The germination inhibition rate and elongation inhibition rate for seeds were as shown in Table 1 below.

【table】

[Table] Example 3 (Confirmation of compounds) In Table 1 above, the structures of the compounds were confirmed for fractions H, I, and J, which had relatively good germination inhibition rate and elongation inhibition rate, and the following compounds were respectively It turned out to be. It was also found that fractions I and J were the same compound. Compound (Fraction H) This compound was confirmed to have the following structural formula from the analysis results below.

【table】

【table】

[Table] ｜
173.84 = C −
｜
176.37 = C −
186.39 −CHO
Compound (Fractions I and J) This compound was confirmed to have the following structural formula from the analysis results below.

【table】

【table】

[Table] ｜
166.20 =C−
｜
168.44 =C−
｜
180.83 =C−
Example 4 (Physiological activity on potato) Each of the above-mentioned compounds and the other compounds were applied to leaves of potato (Norin No. 1) and their activity was examined. That is, each compound was dissolved in methanol to a concentration of 1 μg/1 μ to prepare a solution.
Meanwhile, cut a potato leaf from the stem, insert it into a container filled with deionized water, make two holes in the middle on both sides of the leaf with a needle, and fill the holes on one side with the above solution.
It was applied at a concentration of 100 μg/100 μ and allowed to dry slowly. The hole on the other side is filled with methanol.
100μ was slowly applied in the same manner. As a result, necrosis (necrosis) was observed in the pores of the leaves, and the degree of necrosis was as follows.

[Table] In the table, +++ indicates very large and ++ indicates large.
In the table, +++ indicates very large and ++ indicates large. Example 5 This example demonstrates that a compound is produced by reducing the compound and selectively converting its aldehyde groups to hydroxymethyl groups. 6 mg of the above compound was added to 0.5 mg of tetrahydrofuran.
cc and then 0.8 mg of NaBH ₄ at room temperature after N ₂ substitution
was added for 2.5 hours. As a result of separating and analyzing the compound thus obtained, it was confirmed that a compound (ie, a compound) having the following structure was obtained as a result of the following reaction. Confirmation data for the compound obtained in the above reaction were as follows.

【table】

【table】

【table】

Claims (1)

[Claims] 1. The following general formula [] [However, in the formula, R ₁ represents -CH ₂ OH or -CHO, and R ₂ represents H or -CH ₃ . ] An α-pyrone derivative and a salt thereof. 2 General formula below [However, in the formula, R ₁ represents -CH ₂ OH or -CHO, and R ₂ represents H or -CH ₃ . ] A plant growth regulator containing an α-pyrone derivative or a salt thereof as an active ingredient.