CN115368290A

CN115368290A - Plant growth regulator and preparation method thereof

Info

Publication number: CN115368290A
Application number: CN202210812652.XA
Authority: CN
Inventors: 陈颖; 刘鑫; 柳娴
Original assignee: Hunan University of Technology
Current assignee: Hunan University of Technology
Priority date: 2022-07-12
Filing date: 2022-07-12
Publication date: 2022-11-22

Abstract

The invention provides a plant growth regulator and a preparation method thereof, belonging to the technical field of plant growth regulators, and the structure of the plant growth regulator is shown as follows, wherein n =1-3. The plant growth regulator has excellent effects of promoting cell division and growth, inducing cell differentiation andthe effect of inducing the growth and rooting of the shoots plays an important role in the plant resistance to external stress, and can mobilize the stress resistance of the plant and the content of various endogenous hormones, change the content of chemical components of tissue cells, induce the activity of various enzymes, and the like. The compound has better sterilization and antibacterial effects, can improve the disease resistance and insect resistance of crops, has better effects of promoting growth, resisting diseases, insects and bacteria compared with single auxin plant growth regulators such as indoleacetic acid and the like, improves the crop yield, is easy to degrade, does not cause environmental pollution, has simple synthesis method, wide raw material source and convenient use, and has good application prospect.

Description

Plant growth regulator and preparation method thereof

Technical Field

The invention relates to the technical field of plant growth regulators, in particular to a plant growth regulator and a preparation method thereof.

Background

Plant hormones, also called plant natural hormones or plant endogenous hormones, are organic substances produced by plants themselves and directly or indirectly act on target organs or target tissues to regulate plant growth, and the physiological actions of plant hormones are very complex and can affect division, growth and differentiation of plant roots, plant germination, flowering, fruiting, sex differentiation and the like. Since the naturally synthesized plant hormones have a very small content, it is costly to extract a large amount of plant hormones to increase the yield of crops, and thus, scientists have studied a lot of times and finally found that an organic compound having a structure and an action similar to those of the naturally synthesized plant hormones, i.e., a plant growth regulator, can be synthesized by a chemical synthesis method.

A plant growth regulator is a kind of agricultural chemicals for regulating plant growth and development, including artificially synthesized compound with similar action of natural plant hormone and natural plant hormone extracted from living beings. The plant growth regulator can promote the combined action of various active enzyme substances in the plant body after being absorbed, thereby influencing the physicochemical process of the plant. Plant growth regulators are a general term and generally classified into three main groups according to their effects on plant growth, namely, plant growth promoters including auxin, cytokinin, gibberellin and brassinosteroid, plant growth inhibitors represented by cinnamic acid, coumarin, abscisic acid, salicylic acid and the like, and plant growth retardants including chlormequat chloride, paclobutrazol (PP 333) and uniconazole.

With the increasing decrease of arable land area and the increasing increase of population on the earth and the frequent occurrence of natural disasters, the plant growth regulator is more and more concerned about the aspects of guaranteeing the grain safety and improving the yield. The traditional plant growth regulator has high liquid medicine residue, great pollution, poor use safety, low utilization rate and poor regulating effect, and does not meet the development requirements of ecological agriculture.

Disclosure of Invention

The invention aims to provide a plant growth regulator and a preparation method thereof, which have excellent effects of promoting cell division and growth, inducing cell differentiation and inducing growth and rooting of buds, play an important role in resisting external stress of plants, can regulate the stress resistance of the plants and the content of multiple endogenous hormones, change the content of chemical components of tissue cells, induce the activity of various enzymes and the like. Meanwhile, the compound has good bactericidal and antibacterial effects, can improve the disease resistance and insect resistance of crops, and has better effects of promoting growth, resisting diseases, insects and bacteria and improving the crop yield compared with a single auxin plant growth regulator such as indoleacetic acid and the like.

The technical scheme of the invention is realized as follows:

the invention provides a plant growth regulator, which has a structure shown as a formula I and contains a fluorine-containing indolurea compound;

wherein n =1-3.

The invention further protects a preparation method of the plant growth regulator, which comprises the following steps:

s1, dissolving indole acid in a first solvent, and adding a first base and thionyl chloride to prepare an intermediate A; the chemical reaction formula is as follows:

the first solvent is at least one selected from dichloromethane, trichloromethane, carbon tetrachloride, tetrahydrofuran and acetonitrile; the first alkali is at least one selected from triethylamine, sodium carbonate, diethylamine, DMAP and potassium carbonate;

the mass ratio of the indole acid, the first base and the thionyl chloride is 1: (3-5): (1.2-1.5);

s2, dissolving the intermediate A in a second solvent, and adding a second alkali and fluorophenylurea to prepare a plant growth regulator; the chemical reaction formula is as follows:

the second solvent is at least one selected from dichloromethane, trichloromethane, carbon tetrachloride, tetrahydrofuran, acetonitrile, ethyl acetate and diethyl ether; the second base is at least one selected from triethylamine, sodium carbonate, diethylamine, potassium bicarbonate, sodium bicarbonate, potassium carbonate and ethylenediamine;

the mass ratio of the intermediate A, the second base and the florfenicol is (1.1-1.2): (3-5): 1.

as a further improvement of the present invention, in step S1, the indole acid is selected from at least one of indole acetic acid, indole propionic acid and indole butyric acid; the first solvent is chloroform; the first base is diethylamine.

As a further improvement of the present invention, the ratio of the amounts of the substances of the indole acid, the first base and thionyl chloride in step S1 is 1:5:1.5.

as a further improvement of the present invention, in step S2, the second solvent is chloroform; the second base is diethylamine.

As a further improvement of the present invention, the ratio of the amounts of said intermediate a, second base and florfenicol species in step S2 is 1.2:5:1.

as a further improvement of the invention, the method specifically comprises the following steps:

s1, dissolving indoleacid in a first solvent, adding a first base and thionyl chloride under the condition of 0-room temperature, stirring and reacting for 1-2 hours, adding a saturated sodium bicarbonate solution after the reaction is finished, and filtering to obtain an intermediate A; the first solvent is at least one selected from dichloromethane, trichloromethane, carbon tetrachloride, tetrahydrofuran and acetonitrile; the first alkali is at least one selected from triethylamine, sodium carbonate, diethylamine, DMAP and potassium carbonate;

the mass ratio of the intermediate A, the second base and the fluorophenylurea is (1.1-1.2): (3-5): 1;

s2, dissolving the intermediate A in a second solvent, adding a second alkali and fluorophenylurea at room temperature to 40 ℃, stirring for reaction for 3-5h, and filtering to obtain a plant growth regulator; the second solvent is at least one selected from dichloromethane, trichloromethane, carbon tetrachloride, tetrahydrofuran, acetonitrile, ethyl acetate and diethyl ether; the second base is at least one of triethylamine, sodium carbonate, diethylamine, potassium bicarbonate, sodium bicarbonate, potassium carbonate and ethylenediamine;

the mass ratio of the intermediate A, the second base and the fluorophenylurea is (1.1-1.2): (3-5): 1.

the invention further protects a plant growth regulator composition, which contains the fluorine-containing indoxyl urea compound shown in the formula I as an active component and an agriculturally or forestry acceptable carrier.

Further, the active component also comprises other active components, and the other active components comprise at least one of plant growth regulators such as naphthylacetic acid, sodium naphthylacetate, gibberellin, cytokinin, brassinosteroids and the like.

Furthermore, the plant growth regulator composition can also be added with components such as a nutrient, an insecticide, a film-forming agent and the like. The film forming agent comprises at least one of seaweed powder, sodium carboxymethylcellulose and chitin; the pesticide comprises at least one of imidacloprid, dimehypo, acephate, carbosulfan and monocrotophos; the vitamin, the amino acid and the inorganic salt are contained; the vitamins include at least one of vitamin C, vitamin B1, vitamin B2, vitamin A, vitamin K, vitamin B12, vitamin D and vitamin E; the inorganic salt comprises at least one of sodium chloride, potassium chloride, calcium chloride, magnesium sulfate, ferric chloride, zinc sulfate, copper sulfate, manganese sulfate, zinc chloride, copper chloride and manganese chloride; the amino acid includes at least one of glycine, serine, threonine, valine, tryptophan, leucine, alanine, cysteine, methionine, lysine, isoleucine, and phenylalanine.

As a further improvement of the invention, the health-care food is prepared from the following raw materials in parts by weight: 5-10 parts of a compound shown in a formula I, 1-2 parts of vitamin B and 2-4 parts of brassinolide.

The formulation of the composition of the present invention may be a suspension, an emulsion, a microemulsion, a wettable powder, a water dispersible granule, etc., and in order to improve the utilization rate of the effective components, 1 to 2wt% of a surfactant is usually added when the composition is added into water to prepare a preparation.

The invention further protects the use of the compounds of formula I as defined above for controlling crop pests.

The invention has the following beneficial effects: the compound shown in the formula I is a synthetic plant growth regulator which has bactericidal activity and growth and rooting promotion, has excellent effects of promoting cell division and growth, inducing cell differentiation and inducing growth and rooting of buds, plays an important role in resisting external stress of plants, and can regulate the stress resistance of the plants and the level content of various endogenous hormones, change the content of chemical components of tissue cells, induce the activity of various enzymes and the like. Meanwhile, the compound has good bactericidal and antibacterial effects, can improve the disease resistance and insect resistance of crops, has better effects of promoting growth, resisting diseases, insects and bacteria and improving crop yield compared with a single auxin plant growth regulator such as indoleacetic acid and the like, is easy to degrade, cannot cause environmental pollution, is simple in synthesis method, wide in raw material source, convenient to use and has good application prospect.

The plant growth regulator composition comprises a compound shown as a formula I, vitamin B1 and brassinolide which are used in a synergistic manner, the brassinolide can play a role in the whole growth period of a plant, has the effects of promoting growth, fertilization and fruit enlargement on the plant, can also play a good role in increasing yield, coordinating plant nutrient balance and strongly rooting, accelerates plant growth metabolism, and improves stress resistance of the plant such as drought resistance, cold resistance, salt and alkali resistance and the like; the vitamin B1 can promote the activity of growth synthetase in plants, thereby improving the growth speed of the plants, promoting the growth of the plants and improving the yield, and the vitamin B1 and the vitamin E have good synergistic effect by virtue of the synergy of the two. The plant growth regulator composition can improve the germination rate of seeds, is beneficial to aligning and strengthening seedlings, enhances the drought resistance and disease resistance, improves the effects of disease resistance, insect resistance and bacteria resistance, obviously improves the crop yield, and has the function of synergy.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

This example provides a process for the preparation of a compound of formula I, comprising the steps of:

s1, dissolving 17.5g (0.1 mol) of indoleacetic acid in 200mL of dichloromethane, adding 41.5mL (0.3 mol) of triethylamine at 0 ℃, uniformly stirring and mixing, dropwise adding 50mL of dichloromethane solution containing 8.7mL (0.12 mol) of thionyl chloride, stirring and reacting for 1h at room temperature, after the reaction is finished, adding an equal volume of saturated sodium bicarbonate solution, filtering, washing the solid with 20mL of dichloromethane for 3 times respectively, and drying at 70 ℃ for 2h to obtain 17.5g of yellow powdery intermediate A, wherein the yield is 90.7%; of intermediate A ¹ HNMR(400MHz，DMSO-d6)，δ(ppm)：10.21(b，1H)，7.84(dd，J＝12.0，2.2Hz，4H)，6.82(s，1H)，3.97(s，2H)。

The synthetic route is as follows:

s2, dissolving 21.2g (0.11 mol) of the intermediate A in 200mL of dichloromethane, adding 41.5mL (0.3 mol) of triethylamine and 15.4g (0.1 mol) of fluorophenylurea at room temperature, heating to 40 ℃, stirring for reaction for 3 hours, after the reaction is finished, adding an equal volume of saturated sodium bicarbonate solution, filtering, washing the solid with 20mL of dichloromethane for 3 times respectively, and drying at 55 ℃ for 3 hours to obtain 24.4g of white solid, wherein a sample can be purified by adopting column chromatography to be a plant growth regulator, and the yield is 78.5%. The melting point of the compound of the formula I is 210.4-211.7 ℃. Process for preparing compounds of formula I ¹ HNMR(400MHz，DMSO-d6)，δ(ppm)：10.22(b，1H)，10.12(b，1H)，7.67(d，J＝6.5，2H)，7.18(dd，J＝11.7，3.2Hz，4H)，6.92(d，J＝6.4，2H)，6.72(s，1H)，6.02(b，1H)，3.32(s，2H)。

The synthetic route is as follows:

example 2

s1, dissolving 18.9g (0.1 mol) of indole propionic acid in 200mL of trichloromethane, adding 51.4mL (0.5 mol) of diethylamine at 0 ℃, stirring and mixing uniformly, dropwise adding 50mL of trichloromethane solution containing 10.9mL (0.15 mol) of thionyl chloride, stirring and reacting for 2 hours at room temperature, after the reaction is finished, adding an equal volume of saturated sodium bicarbonate solution, filtering, washing the solid with 20mL of trichloromethane for 3 times, and drying to obtain 18.6g of light yellow powdery intermediate A, wherein the yield is 89.9%; of intermediate A ¹ HNMR(400MHz，DMSO-d6)，δ(ppm)：10.22(b，1H)，7.82(dd，J＝12.4，2.1Hz，4H)，6.80(s，1H)，3.98(t，J＝4.8Hz，2H)，3.94(t，J＝5.0Hz，2H)。

The synthetic route is as follows:

s2, dissolving 24.8g (0.12 mol) of the intermediate A in 200mL of trichloromethane, adding 51.4mL (0.5 mol) of diethylamine and 15.4g (0.1 mol) of fluorophenylurea at room temperature, heating to 40 ℃, stirring for reaction for 5 hours, after the reaction is finished, adding an equal volume of saturated sodium bicarbonate solution, filtering, washing the solid with 20mL of trichloromethane for 3 times respectively, and drying to obtain 24.4g of milky white solid, wherein a sample can be purified by adopting column chromatography to serve as a plant growth regulator, and the yield is 75.1%. The melting point of the compounds of the formula I is 214.7-216.1 ℃. Of the compound of formula I ¹ HNMR(400MHz，DMSO-d6)，δ(ppm)：10.22(b，1H)，10.12(b，1H)，7.67(d，J＝6.5，2H)，7.18(dd，J＝11.7，3.2Hz，4H)，6.92(d，J＝6.4，2H)，6.72(s，1H)，6.02(b，1H)，3.30(t，J＝4.2Hz，2H)，3.27(t，J＝4.0Hz，2H)。

The synthetic route is as follows:

example 3

Weighing 5g of the compound of the formula I prepared in example 1 and 1g of sodium dodecyl benzene sulfonate, mixing and ball milling for 1 hour, sieving by a 500-mesh sieve, adding into 94g of water, stirring uniformly, and homogenizing at 10000r/min for 3min to obtain the suspending agent.

Example 4

Weighing 5g of the compound of the formula I prepared in example 2 and 1g of sodium dodecyl benzene sulfonate, mixing and ball milling for 1h, sieving with a 500-mesh sieve, adding into 94g of water, stirring uniformly, and homogenizing at 10000r/min for 3min to obtain the suspending agent.

Example 5

Weighing 5g of the compound of the formula I prepared in example 2, 1g of vitamin B1, 2g of brassinolide and 1g of sodium dodecyl benzene sulfonate, mixing, ball-milling for 1h, sieving with a 500-mesh sieve, adding 91g of water, stirring uniformly, and homogenizing at 10000r/min for 3min to obtain the suspending agent.

Comparative example 1

Compared to example 5, no vitamin B1 was added, and other conditions were unchanged.

Weighing 5g of the compound of the formula I prepared in the example 2, 3g of brassinolide and 1g of sodium dodecyl benzene sulfonate, mixing, ball-milling for 1h, sieving with a 500-mesh sieve, adding 91g of water, uniformly stirring, and homogenizing at 10000r/min for 3min to obtain the suspending agent.

Comparative example 2

Compared with example 5, brassinolide was not added, and other conditions were not changed.

Weighing 5g of the compound of the formula I prepared in example 2, 3g of vitamin B1 and 1g of sodium dodecyl benzene sulfonate, mixing, ball-milling for 1h, sieving with a 500-mesh sieve, adding 91g of water, stirring uniformly, and homogenizing at 10000r/min for 3min to obtain the suspending agent.

Test example 1 seed soaking rooting promotion test

After the suspending agents prepared in examples 3-5 and comparative examples 1-2 of the invention are diluted to have the content of effective substances (the compound of formula I prepared in example 1 or example 2) of 30 mug/mL, wheat seeds with full grains and uniform size are selected, the seeds are respectively soaked in hypochlorous acid solution for 10min for sterilization, the diluted solution is used for soaking and culturing the seeds for 7h in a beaker, 10 grains of wheat are treated in each group, the steps are repeated for 3 times, the wheat seeds are uniformly placed on a wet paper bed after treatment, the distance of 2cm is kept between the seeds, the seeds are ensured to fully absorb moisture, then the seeds are subjected to germination acceleration treatment for 24h, and distilled water is added periodically during the germination acceleration treatment to keep the paper bed wet. After the main root of the wheat is exposed about 2mm, the main root of the wheat is planted in a solid culture medium and then is cultured in a full-intelligent climatic chamber. After 42h, the height of the main root and stem was measured with calipers. The promotion rate of the main root, lateral root and stem height was calculated by treating with gibberellin 30. Mu.g/mL, indoleacetic acid 30. Mu.g/mL and clear water as controls, and the results are shown in Table 1.

Promotion rate (%) of main root, lateral root or stem height = (main root length, lateral root length or stem height of the group-main root length, lateral root length or stem height of the clear water group)/main root length, lateral root length or stem height of the clear water group × 100%.

TABLE 1

As shown in the table, the compound of the formula I prepared by the invention has the technical effect of promoting the rooting of wheat seeds, and is superior to indoleacetic acid and gibberellin. In example 5, the compound plant regulator composition is adopted, which can obviously promote the rooting of seeds.

Test example 2 seed germination acceleration test

After diluting the suspending agent prepared in examples 3-5 and comparative examples 1-2 of the present invention to a content of an effective substance (the compound of formula i prepared in example 1 or example 2) of 30 μ g/mL, wheat seeds with full grains and uniform size were selected, the seeds were soaked in hypochlorous acid solution for 10min for sterilization, and then soaked in the above diluent solution in a beaker for 24h, each group was treated with 100 grains of wheat, and the treatment was repeated for 3 times, and then the wheat seeds were placed on a clean culture dish uniformly with a distance of 0.5cm between the seeds, and then cultured in a fully intelligent climate box at 25 ℃ under a humidity of 50%, during which time water was continuously supplemented, and the germination of each group was observed, and the germination of each group was judged as germination when the length of the embryo was about half of the length of the seed, and the germination of each group of wheat seeds was counted after 24 h. The germination acceleration rate was calculated by using gibberellin at 30. Mu.g/mL, indoleacetic acid at 30. Mu.g/mL and clear water as controls, and the results are shown in Table 2.

Germination promotion rate (%) = (average germination rate of the group-average germination rate of clear water group)/average germination rate of clear water group × 100%.

TABLE 2

Group of	Average germination percentage (%)	Germination acceleration Rate (%)
			Example 3	90.2	44.32
Example 4	91.5	46.40
			Example 5	94.7	51.52
Comparative example 1	90.5	44.80
			Comparative example 2	90.9	45.44
Gibberellins	81.4	30.24
			Indoleacetic acid	83.7	33.92
Clean water	62.5	/

As shown in the table, the compound shown in the formula I has good activity of promoting wheat seed germination, and is superior to indoleacetic acid and gibberellin. In example 5, the compound plant regulator composition is adopted, so that the germination activity can be obviously improved.

Test example 3 cucumber leaf expansion test

Soaking cucumber of Jinzhang No. 1, sowing in a container with a cover and containing 1% agar, culturing at 25 + -2 deg.C in dark for 72 hr, and selecting out leaves with uniform size. The suspending agents prepared in examples 3-5 and comparative examples 1-2 of the invention are diluted to have the content of active substances (the compound of formula I prepared in example 1 or example 2) of 10 mug/mL, thidiazuron and indoleacetic acid are dissolved in DMF, a control solution with the content of 10 mug/mL is prepared by using 1wt% sodium dodecyl benzene sulfonate solution, clear water is set as a blank control group, the 8 solutions are respectively added into 8 groups of culture dishes, 10 cotyledons with similar sizes are randomly placed in each group of culture dishes and cultured under the light intensity environment of 25 +/-2 ℃,3000 +/-200 Lx, and the fresh weight of each 10 cotyledons is measured after 72 hours. Each treatment group was repeated 3 times and the results averaged. The results are shown in Table 3.

Cucumber cotyledon expansion (%) = (fresh weight of 10 cotyledons after treatment-fresh weight of 10 cotyledons before treatment)/fresh weight of 10 cotyledons before treatment × 100%.

TABLE 3

Group of	Expansion of cucumber cotyledon (%)
		Example 3	87.5
Example 4	88.7
		Example 5	93.2
Comparative example 1	89.2
		Comparative example 2	89.5
Thidiazuron	70.2
		Indoleacetic acid	68.3
Blank control group	45.2

As can be seen from the table, the compound of formula I prepared by the invention has good cell division activity, and the cucumber leaf expansion activity is superior to that of indolylacetic acid and thidiazuron. In example 5, the compound plant regulator composition is adopted, which can obviously improve the cell division activity.

Test example 4 measurement of bactericidal Activity

1g of the compound of the formula I prepared in example 1 or example 2 is dissolved in 20mL of dimethyl sulphoxide (DMSO) and then diluted with a 0.2% by weight aqueous solution of Tween-80 emulsifier. The pathogenic bacteria to be tested include rice bacterial blight (Xanthomonas oryzae pv. Oryzae), tomato leaf mold (Fulvia fulva), xanthomonas graminis (Xanthomonas campestris pv. Idulosa), watermelon anthracnose (Colletotrichum orbiculare), and corn northern leaf blight (Exserohilum turcicum).

The test method comprises the following steps: according to the experimental criteria of indoor bioassay of pesticides, namely bactericide, an in-vitro plate method is adopted, a blank group is a mixed solution of DMSO and 0.2wt% of Tween-80 aqueous solution, and the content of the DMSO is not more than 2%. Sucking 1mL of liquid medicine under aseptic condition, adding into a culture dish, adding 9mL of PDA culture medium, shaking to obtain a medicine-containing plate, and replacing the liquid medicine with 1mL of sterile water in blank control. Cutting the plate along the outer edge of the hyphae with a 4mm diameter punch, transferring to a medicated plate, repeating each group for 3 times, keeping the temperature at 25 + -1 deg.C and humidity at 70%, and making 5% CO ₂ Culturing for 72h under the condition, measuring the average bacteria disc expansion diameter, and calculating the control effect. The concentration of the compound of formula I prepared in example 1 or example 2 was 100. Mu.g/mL when tested.

The test results are shown in Table 4.

Control effect (%) = (blank colony diameter-treated colony diameter)/(blank colony diameter-4) × 100%

TABLE 4

As can be seen from the above table, the compounds of formula I prepared by the present invention exhibit certain fungicidal activity.

Test example 5 prevention and control test for yellowing disease of betel nut

The suspending agents prepared in examples 3 to 5 and comparative examples 1 to 2 of the present invention were diluted to have an active substance (the compound of formula i prepared in example 1 or example 2) content of 100mg/mL to obtain test solutions, and 7 cells including 5 test zones, 1 blank control zone and 1 control zone were selected on a betel nut field (betel nut variety No. 1), each cell having about 30 betel nut plants, a row spacing of 2m and a row spacing of 2.2m. The test zones were sprayed with the test solutions prepared above, the blank control zone was sprayed with an equal amount of clear water, and the control zone was sprayed with an equal amount of 1.8% sodium nitrophenolate aqueous solution (using a 3000-fold solution, purchased from Jiang Tan agro-chemical Co., ltd., jiangsu). The spraying time is that the first time of spraying is started in the initial period of areca-nut yellowing disease, and then the spraying is carried out for 1 time every 15 days for 5 times in total. Investigating the disease condition of all areca nuts 60 days after the last application of the medicine, taking the total plant number and each stage of disease plant number as a unit, and calculating the disease index and the prevention and control effect. The disease grading standard is as follows: grade 0 (normal plant, green leaf, extended); level 1 (leaf spreading, yellowing of 1-2 leaves in the canopy); 2-stage (the leaves become smaller, and 3-5 leaves in the canopy are yellowed); grade 3 (the whole leaf is yellowed, the crown width is reduced by less than 1/2, and the result capability is obviously reduced); grade 4 (yellowing and even withering of the whole plant, reduction of crown width by more than 1/2 and loss of economic value).

The prevention effect calculation formula is as follows:

control effect (%) = [1- (CK) ₀ ×DT ₁ )/(CK ₁ ×DT ₀ )]×100％

In the formula, CK ₀ The disease index before drug administration is a blank control area; CK (CK) ₁ The disease index after drug administration is a blank control area; DT ₀ The disease index before drug application in the test area; DT ₁ Is the disease index after the drug is applied to the test area.

The results are shown in Table 5.

TABLE 5

Group of	Index of pre-drug condition	Index of disease after administration	Control effect (%)
				Example 3	10.17	11.17	54.79
Example 4	10.04	10.35	57.56
				Example 5	10.20	9.57	61.38
Comparative example 1	10.25	12.16	51.16
				Comparative example 2	10.18	11.35	54.10
Compound sodium nitrophenolate	10.34	15.12	39.80
				Clear water	10.02	24.34	/

As can be seen from the above table, the compound of formula I prepared in example 1 or 2 has a better effect of preventing and controlling betel nut yellowing. In the embodiment 5, the compound plant regulator composition is adopted, so that the prevention and control effect can be obviously improved.

In comparative examples 1 and 2, compared with example 5, the effects of promoting rooting, sprouting, cotyledon expansion, disease resistance, and the like were reduced without adding vitamin B1 or brassinolide, respectively. The brassinolide can play a role in the whole growth cycle of the plant, has the effects of promoting growth, fertilization and fruit enlargement on the plant, also has the functions of increasing yield, coordinating the nutrition balance of the plant and strongly rooting, accelerates the growth and metabolism of the plant, and improves the stress resistance of the plant such as drought resistance, cold resistance, salt and alkali resistance and the like; the vitamin B1 can promote the activity of growth synthetase in plants, thereby improving the growth speed of the plants, promoting the growth of the plants and improving the yield, and the vitamin B1 and the vitamin E have good synergistic effect by virtue of the synergy of the two. The plant growth regulator composition disclosed by the invention comprises the compound shown as the formula I, vitamin B1 and brassinolide which are used cooperatively, so that the germination rate of seeds can be improved, seedlings can be aligned and strong, the drought resistance and the disease resistance are enhanced, the effects of disease resistance, insect resistance and bacterium resistance are improved, the crop yield is obviously improved, and the synergistic effect is realized.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims

1. A plant growth regulator is characterized in that the structure of the plant growth regulator is a fluorine-containing indolurea compound shown as a formula I;

formula I;

wherein n =1-3.

2. A method for preparing a plant growth regulator according to claim 1, comprising the steps of:

s1, dissolving indoleacid in a first solvent, and adding a first base and thionyl chloride to prepare an intermediate A; the chemical reaction formula is as follows:

；

；

the second solvent is at least one selected from dichloromethane, trichloromethane, carbon tetrachloride, tetrahydrofuran, acetonitrile, ethyl acetate and diethyl ether; the second base is at least one of triethylamine, sodium carbonate, diethylamine, potassium bicarbonate, sodium bicarbonate, potassium carbonate and ethylenediamine;

3. the method according to claim 2, wherein the indole acid in step S1 is at least one selected from the group consisting of indoleacetic acid, indolepropionic acid, and indolebutyric acid; the first solvent is trichloromethane; the first base is diethylamine.

4. The method according to claim 2, wherein the ratio of the amounts of the indole acid, the first base and thionyl chloride in step S1 is 1:5:1.5.

5. the method according to claim 2, wherein the second solvent in step S2 is chloroform; the second base is diethylamine.

6. The process according to claim 2, characterized in that the ratio of the quantities of said intermediate a, of second base and of florfenicol substance in step S2 is 1.2:5:1.

7. the preparation method according to claim 2, comprising the steps of:

8. a plant growth regulator composition comprising a compound of formula i as defined in claim 1 as an active ingredient and an agriculturally or forestry acceptable carrier.

9. The plant growth regulator composition according to claim 8, which is prepared from the following raw materials in parts by weight: 5-10 parts of a compound shown in a formula I, 1-2 parts of vitamin B and 2-4 parts of brassinolide.

10. The use of a compound of formula i as claimed in claim 1 for controlling crop pests.