PLANT GROWTH REGULATOR AND METHOD FOR PROMOTING PLANT GROWTH

Abstract

In order to provide a plant growth regulator with an excellent plant growth promoting effect, the plant growth regulator of the present invention includes a compound represented by Formula (I) or its tautomer, or an agrochemically acceptable salt thereof.

##STR00001##

where R.sup.1 and R.sup.2 each independently represent a hydrogen atom or an alkyl group having from 1 to 4 carbon atoms, and R.sup.3 to R.sup.5 each independently represent an alkyl group having from 1 to 4 carbon atoms.

Claims

1-8. (canceled)

9. A plant growth promoter comprising a compound represented by Formula (I) or its tautomer, or an agrochemically acceptable salt thereof as an active ingredient: ##STR00006## where in Formula (I), R.sup.1 and R.sup.2 each independently represent a hydrogen atom or an alkyl group having from 1 to 4 carbon atoms, and R.sup.3 to R.sup.5 each independently represent an alkyl group having from 1 to 4 carbon atoms.

10. The plant growth promoter according to claim 9, comprising a compound represented by Formula (I) or an agrochemically acceptable salt thereof as an active ingredient.

11. The plant growth promoter according to claim 9, wherein in Formula (I), at least one of R.sup.1 and R.sup.2 is a hydrogen atom.

12. The plant growth promoter according to claim 9, wherein in Formula (I), R.sup.1 and R.sup.2 are hydrogen atoms, and R.sup.3 to R.sup.5 are methyl groups.

13. The plant growth promoter according to claim 9, wherein the compound represented by Formula (I) is L-(+)-ergothioneine.

14. A method for promoting plant growth comprising treating a plant with a compound represented by Formula (I) or its tautomer, or an agrochemically acceptable salt thereof: ##STR00007## where in Formula (I), R.sup.1 and R.sup.2 each independently represent a hydrogen atom or an alkyl group having from 1 to 4 carbon atoms, and R.sup.3 to R.sup.5 each independently represent an alkyl group having from 1 to 4 carbon atoms.

15. An agent for increasing seed yield comprising a compound represented by Formula (I) or its tautomer, or an agrochemically acceptable salt thereof as an active ingredient: ##STR00008## where in Formula (I), R.sup.1 and R.sup.2 each independently represent a hydrogen atom or an alkyl group having from 1 to 4 carbon atoms, and R.sup.3 to R.sup.5 each independently represent an alkyl group having from 1 to 4 carbon atoms.

16. An agent for increasing the number of flowers comprising a compound represented by Formula (I) or its tautomer, or an agrochemically acceptable salt thereof as an active ingredient: ##STR00009## where in Formula (I), R.sup.1 and R.sup.2 each independently represent a hydrogen atom or an alkyl group having from 1 to 4 carbon atoms, and R.sup.3 to R.sup.5 each independently represent an alkyl group having from 1 to 4 carbon atoms.

Description

EXAMPLES

Example 1

Sample

[0093] Arabidopsis thaliana (Col-O) was sown in plastic pots having a width of 65 mm, a depth of 65 mm, and a height of 70 mm, three individuals per pot. Plastic deep dishes each having a diameter of 160 mm and a height of 28 mm were prepared, and three pots were respectively placed therein. As soil, 100 mL of vermiculite, 50 mL of granular soil (JA Granular Kumiai Synthetic Soil No. 3), and 50 mL of vermiculite were placed in each pot in this order.

Control Conditions

[0094] In a thermostatic chamber set at room temperature of 25° C., the light period was 16 hours and the dark period was 8 hours. The light conditions were set using a fluorescent lamp (PLANT FLEC, 40 W LED fluorescent lamp for plant growth, electric bulb color, available from Nippon Medical and Chemical Instruments Co., Ltd.) so that the light intensity was 5000 lx in the central part under the fluorescent lamp irradiation. Water supply was done from the bottom, and the water level was set at about 5 mm. Ergothioneine treatment was started 4 weeks after seeding. More specifically, on the 21st, 23rd, 25th, and 27th days after seeding, 50 mL of a 1 mM L-(+)-ergothioneine (available from Cayman Chemical) aqueous solution was added instead of water supply.

Verification

[0095] On the 37th day after seeding, the plant height (cm) and the number of flowers and fruits per Arabidopsis thalianawere measured. The results are shown in Table 1.

Comparative Example 1

[0096] The same operation as in Example 1 was carried out except that L-(+)-ergothioneine in the aqueous solution was replaced with oxidized glutathione (available from Wako Pure Chemical Industries, Ltd.).

Comparative Example 2

[0097] The same operation as in Example 1 was carried out except that the L-(+)-ergothioneine aqueous solution was replaced with distilled water.

Example 2

Sample

[0098] One individual Arabidopsis thaliana (Col-O) was sown in a plastic pot having a diameter of 60 mm and a height of 55 mm. Plastic deep dishes each having a diameter of 160 mm and a height of 28 mm were prepared, and six pots were respectively placed therein. As soil, 45 mL of vermiculite, 22.5 mL of granular soil (JA Granular Kumiai Synthetic Soil No. 3), and 22.5 mL of vermiculite were placed in each pot in this order.

Control Conditions

[0099] The procedure was the same as in Example 1, except that the room temperature was set to 22° C.

Verification

[0100] On the 85th day after seeding, seeds were harvested, and the seed yield (mg/plant) was measured. The results are shown in Table 2.

Example 3

[0101] The same operation as in Example 2 was carried out except that the concentration of L-(+)-ergothioneine aqueous solution was set to 0.1 mM.

Example 4

[0102] The same operation as in Example 2 was carried out except that the concentration of L-(+)-ergothioneine aqueous solution was set to 0.01 mM.

Comparative Example 3

[0103] The same operation as in Example 2 was carried out except that L-(+)-ergothioneine in the aqueous solution was replaced with oxidized glutathione (available from Wako Pure Chemical Industries, Ltd.).

Comparative Example 4

[0104] The same operation as in Example 2 was carried out except that L-(+)-ergothioneine in the aqueous solution was replaced with L-glutamic acid (available from Wako Pure Chemical Industries, Ltd.).

Comparative Example 5

[0105] The same operation as in Example 2 was carried out except that L-(+)-ergothioneine in the aqueous solution was replaced with L-proline (available from Wako Pure Chemical Industries, Ltd.).

Comparative Example 6

[0106] The same operation as in Example 2 was carried out except that the L-(+)-ergothioneine aqueous solution was replaced with distilled water.

Example 5

Sample

[0107] The same operation as in Example 2 was carried out.

Control Conditions

[0108] The same operation as in Example 1 was carried out except that the room temperature was set at 22° C. and L-(+)-ergothioneine was added 2 weeks after seeding, more specifically on the 8th, 10th, 12th, and 14th days.

Verification

[0109] On the 82nd day after seeding, seeds were harvested, and the seed yield (mg/plant) was measured. The results are shown in Table 3.

Example 6

[0110] The same operation as in Example 5 was carried out except that L-(+)-ergothioneine was added 4 weeks after seeding, more specifically on the 22nd, 24th, 26th, and 28th days.

Comparative Example 7

[0111] The same operation as in Example 5 was carried out except that oxidized glutathione was used in place of L-(+)-ergothioneine in the aqueous solution and added 4 weeks after seeding, more specifically on the 22nd, 24th, 26th, and 28th days.

Comparative Example 8

[0112] The same operation as in Example 5 was carried out except that the L-(+)-ergothioneine aqueous solution was replaced with distilled water.

Analysis

[0113] The ratio of “grass height” and “flowers and fruits” for Example 1, Comparative Example 1, and Comparative Example 2 to the results of Comparative Example 2 are shown in Table 1 as “Ratio”, respectively. The “seed yield” for Examples 2 to 4 and Comparative Examples 3 to 6 are shown as “Ratio” in Table 2, where the value for Comparative Example 6 is set to 1. The “seed yield” for Examples 5 and 6 and Comparative Examples 7 and 8 are shown as “Ratio” in Table 3, where the value for Comparative Example 8 is set to 1.

TABLE-US-00001 TABLE 1 Plant height Flower and Fruit Test compound (cm) Ratio (Number/plant) Ratio Example 1 L-(+)-ergothioneine 29 1.3 26 1.7 Comparative Oxidized glutathione 24 1.1 22 1.5 Example 1 Comparative — 22 1.0 15 1.0 Example 2

TABLE-US-00002 TABLE 2 Compound concentration Seed yield Test compound (mM) (mg/plant) Ratio Example 2 L-(+)-ergothioneine 1 142 1.7 Example 3 L-(+)-ergothioneine 0.1 130 1.5 Example 4 L-(+)-ergothioneine 0.01 109 1.3 Comparative Oxidized glutathione 1 100 1.2 Example 3 Comparative L-glutamic acid 1 90 1.0 Example 4 Comparative L-proline 1 102 1.2 Example 5 Comparative — — 86 1.0 Example 6

TABLE-US-00003 TABLE 3 Time of treatment Seed yield Test compound (Week) (mg/plant) Ratio Example 5 L-(+)-ergothioneine 2 140 2.0 Example 6 L-(+)-ergothioneine 4 114 1.7 Comparative Oxidized glutathione 4 92 1.3 Example 7 Comparative — — 69 1.0 Example 8