JPH0355445B2 - - Google Patents

Description

[Detailed description of the invention]

This invention relates to a plant growth regulator. A group of compounds called gibberellins are known as substances that have plant growth regulating effects. This group of compounds includes those produced by microorganisms, such as Gibberella Fujikuroi, and those obtained from higher plants.
Among these, when comparing those with 20 carbon atoms, microbial gibberellin has the following entogiberellin skeleton.
One notable difference is that gibberellins from higher plants have a hydroxyl group at the 13th position, whereas gibberellins do not have a hydroxyl group at the 13th position. On the other hand, as a biosynthetic pathway for gibberellin, microbial gibberellin is an enzyme that does not have a hydroxyl group.
It is thought that gibberellins of higher plants are biosynthesized from kaurene or ento-kaurene-19-acid via steviol having a hydroxyl group. R=H Ento-kaurene-19-acid R=OH Steviol According to JP-A No. 55-120794, even if microorganisms are cultured by adding steviol, which is a precursor of the above-mentioned higher plant gibberellin, to the medium, higher plant gibberellin is generally not produced. However, it is said that gibberellins from higher plants can only be obtained by culturing Gibberella fujikuroi, a microbial gibberellin-producing bacterium, in the presence of an inhibitor of gibberellin biosynthesis. However, the inventors found that when Fusarium bacteria, which are not gibberellin-producing bacteria, were cultured in a medium supplemented with a glycoside containing steviol as a true aglycone (hereinafter referred to as steviol glycoside), a plant growth-regulating effect was observed in the medium. They discovered that a substance having the following properties was accumulated and completed this invention. That is, the present invention relates to a culture solution obtained by culturing steviol glycoside-metabolizing bacteria belonging to the genus Fusarium in a medium supplemented with steviol glycosides, a culture solution from which bacterial cells have been removed, and a concentrate or extract thereof. It is a plant growth regulator consisting of The steviol glycoside metabolizing bacteria belonging to the genus Fusarium used in this invention include Fusarium Oxysporum, Fusarium Lini, Fusarium Mori (F.
Mori) etc. are used. Furthermore, steviol glycosides include stevioside, rebaudioside A, dulcoside A, steviolobioside, and the like. The culture method is basically similar to that of general microorganisms, but deep culture using a liquid medium is usually advantageous. A synthetic medium, a semi-synthetic medium, or a natural medium is used as the medium, and its composition includes glucose, starch, glycerin, etc. as a carbon source, and meat extract, peptone, cotton meal, soybean flour, and corn steep liquor as a nitrogen source. , urea, etc. In addition, metal salts and phosphates may be added. Steviol glycosides may be present in the medium from the beginning or may be added during the cultivation. The culture temperature is around 30℃ or appropriate.
As the culture capacity increases, seed culture is performed and inoculated as appropriate. Generally, a suitable culture time is about 20 to 200 hours. The culture solution obtained in this way can be sterilized as it is and used as a plant growth regulator.
It can also be used after removing the bacterial cells. It can also be used as an extract obtained by concentrating the culture solution, lyophilizing it, or extracting it with an organic solvent and distilling off the solvent.
Furthermore, the active ingredients therein may be separated, collected, and purified by utilizing, for example, differences in solubility to solvents, differences in affinity to adsorbents, and the like. Since the plant growth regulator of the present invention has an effect of promoting or inhibiting plant growth, it can be used for the purposes of promoting cultivation, suppressing elongated branches, preventing lodging, etc. of various plants. The method of use varies depending on the purpose of use and the target plant, but foliar spraying or soil treatment is generally appropriate. When used, it can be mixed with various carriers depending on the usage situation and used as powders, granules, tablets, wettable powders, emulsions, etc. In addition, spreading agents, insecticides, fungicides,
It may be used by mixing with fertilizer etc. Next, Examples of the plant growth regulator according to the present invention will be shown, and the effects of the present invention will be clarified through test examples. Example 1 Cut 200g of yam into small pieces and add 30g of yams with 1 part of water.
After boiling for a minute, strain and add glucose to the resulting liquid.
g was added to prepare a basic medium. 50ml of this basic medium
The mixture was placed in a 250 ml Erlenmeyer flask, capped with a cotton stopper, and sterilized under high pressure in an autoclave. On the other hand, the cells of Fusarium oxysporum IFO5942 cultured for 5 days on the slope of a test tube using the same medium were collected in 10 ml of sterile water, centrifuged, and the precipitate was collected in 10 ml of sterile water.
1 ml of the suspension was inoculated into the medium in the Erlenmeyer flask. Stevioside is used as the steviol glycoside, and 100,
A predetermined amount of 250 or 500 ppm was added to the medium before inoculation. After inoculation and shaking culture at 27℃ for 6 days,
A culture solution from which bacterial cells were removed was obtained. Example 2 A culture solution without bacterial cells was obtained in the same manner as in Example 1 except that Fusarium linii IFO5880 was used as the bacteria. Example 3 A culture solution without bacterial cells was obtained in the same manner as in Example 1, except that Fusarium mori Hypomyces solani IFO7707 was used as the bacteria. Example 4 A culture solution from which bacterial cells were removed was obtained in the same manner as in Example 1, except that steviol bioside was used as the steviol glycoside. Example 5 Freeze-dried product of the culture solution obtained in Example 1 2 parts Talc 98 parts The above ingredients were mixed to form a powder. Example 6 Freeze-dried product of the culture solution obtained in Example 2 20 parts Sodium ligninsulfonate 2 parts Polyoxyethylene alkyl ether 2 parts Clay 76 parts The above ingredients were mixed to prepare a wettable powder. Test Example 1 Rice seeds (variety: Tanginbozu) were immersed in running water at 25°C for 30 hours to germinate. Ten germinated seeds were placed in a test tube with an inner diameter of 3 cm and a length of 14 cm lined with a disc-shaped paper. 2 ml of the culture solution obtained in Example 1 was injected into this, and the mixture was heated at 30°C under irradiation of 2500 lux for 6 hours.
The seedlings were grown for days, and the lengths of the second leaf sheath and radicle of each seedling were measured. As a control, a culture solution obtained without adding stevioside was used, and for comparison, distilled water and an aqueous stevioside solution were used in the same manner. The results are shown in Table 1. Test Example 2 Test Example 1 except that the culture solution obtained in Example 2 was used.
operated in the same way. The results are shown in Table 1. In Table 1, C1 and C2 are the culture solutions obtained without adding stevioside, E1 and E2 are the culture solutions obtained in Examples 1 and 2, respectively, DW is distilled water, ST is the stevioside aqueous solution, and is the average value. shows.

【table】

[Table] From the above results, the culture solutions obtained in Examples 1 and 2 promoted the growth of leaves or roots of rice plants compared to culture solutions obtained without adding stevioside, distilled water, and stevioside aqueous solutions. I found out what to do. Test Example 3 Test Example 1 except that the culture solution obtained in Example 3 was used.
operated in the same way. The results are shown in Table 2. In Table 2, C3 is the culture solution obtained without adding stevioside, E3 is the culture solution obtained in Example 3, and GA
represents gibberellin A, DW, ST and has the same meaning as in Table 1.

【table】

[Table] From the above results, it was found that the culture solution obtained in Example 3 inhibited the growth of roots of grass, contrary to gibberellin. Test Example 4 Lettuce seeds (variety: Great Lakes) were placed on absorbent cotton placed in a shear dish with an inner diameter of 3 cm, 10 seeds per shear dish, 2 ml of the culture solution obtained in Example 4 was injected, and the seeds were incubated at 21°C under light conditions. The seedlings were grown for 6 days, and the hypocotyl length, root length, and leaf length of each seedling were measured. As a control, a culture solution obtained without adding steviolobioside was used, and for comparison, the same procedure was carried out using distilled water and an aqueous solution of steviolobioside. The results (average values) are shown in Table 3. In Table 3, C4 indicates the culture solution obtained without adding steviolobioside, E4 indicates the culture solution obtained in Example 4, DW indicates distilled water, and SB indicates steviolobioside.

[Table] From the above results, it was found that the culture solution obtained in Example 4 had a tendency to suppress the germination and growth of lettuce, contrary to steviolobioside. Reference Test Example Gibberella fujikuroi IFO5268 was cultured in the same manner as in Example 1, and the same test as in Test Example 4 was conducted using the obtained culture solution. The results (average values) are shown in Table 4. In Table 4, CR indicates a culture solution obtained without the addition of stevioside, RE indicates a culture solution obtained with the addition of stevioside, DW indicates distilled water, and ST indicates stevioside.

[Table] From the above results, it was found that when Gibberella fujikuroi was cultured, unlike the case of Fusarium genus bacteria, there was almost no production of substances having a plant growth regulating effect.

Claims (1)

[Claims] 1. A culture solution obtained by culturing steviol glycoside-metabolizing bacteria belonging to the genus Fusarium in a medium supplemented with steviol glycosides, a culture solution from which bacterial cells have been removed,
Plant growth regulators consisting of concentrates or extracts thereof.