DE2619841A1 - Plant growth regulant compsns. - contg. (2)-nitro-phenyl-phosphonic acids and their esters and sodium salts - Google Patents

Abstract

New agents for regulating plant growth contain phenyl-phosphonic acid deriv. of formula (I) in which R is H or C2H5; R1 is H, C2H5 or Na; and R2 is H or Cl. (I) interfere with the metabolism of plants and can be used as plant growth regulators. They can be used e.g. for inhibiting plant growth (e.g. of grasses in lawns or of grasses and other plants on roadside verges), for shortening stem growth of cereals to prevent lodging, for inhibiting vegetative growth so as to permit denser planting of crops, for increasing blossoming and fruit formation at the expense of vegetative growth, for promoting vegetative growth where the vegetative parts of plants re used for crop purposes, for increasing crop yields by altering plant metabolism (e.g. to increase sugar content of beet or protein content of soya), for forming parthenocarpic fruits, for influencing the sex of flowers, for increasing the formation of plant products (e.g. stimulating latex flow in rubber trees), for increasing lateral branching by breaking apical dominance, for inhibiting suckering (e.g. of tobacco plants), for effecting defoliation, for preventing premature fruit drop, for accelerating fruit abscission, for accelerating or retarding ripening, for influencing dormancy, for inducing halophilic properties in plants and/or for inducing frost and drought resistance. Specific (I) include 2-nitrophenylphosphonic acid.

Description

Means for regulating plant growth

The present invention relates to the use of some known Phenylphosphonic acid derivatives as active ingredients for regulating plant growth.

The use of 2-nitrophenylphosphonic acid as a bactericide is already in place previously known compare z. B. G. O.

Doak et al. Antibiotics + Chemotherapy "8, 342-348 (195827.

It is also known that succinic acid-2,2-dimethylhydrazide has plant growth-regulating properties (see R. Wegler "Chemie der Plant protection and pesticides ", Volume 2, page 265).

It is also known that the unsubstituted phenylphosphonic acid is a Has plant growth-regulating effectiveness (see German Offenlegungsschrift 1 916 147). So can the succinic acid-2,2-dimethylhydrazide and the unsubstituted Phenylphosphonic acid to inhibit the vegetative growth of cereals, such as. B. Barley or wheat, can be used. The effect of these substances is, however, before especially with low active ingredient concentrations and expenditures, not always completely satisfactory.

It has now been found that the partially known phenylphosphonic acid derivatives of the formula in which R stands for hydrogen or ethyl, R1 stands for hydrogen, ethyl or a sodium atom and R2 stands for hydrogen or chlorine, have strong plant growth-regulating properties.

The phenylphosphonic acid derivatives which can be used according to the invention surprisingly show a better plant growth regulating effect than that from the prior art well-known succinic acid-2,2-dimethylhydrazide and the well-known unsubstituted one Phenylphosphonic acid, which is recognized as having a good effect and has the same effect are. The substances that can be used according to the invention are therefore a valuable asset Technology.

The phenylphosphonic acid derivatives to be used according to the invention are generally defined by the formula (I).

Examples of the compounds of the formula (I) are specifically called: 2-nitrophenylphosphonic acid 2-nitrophenylphosphonic acid monosodium salt 2-Nitro-4-chlorophenylphosphonic acid diethyl ester. 2-Nitro-5-chlorophenylphosphonic acid diethyl ester 2-Nitro-phenylphosphonic acid diethyl ester The phenylphosphonic acid derivatives which can be used according to the invention of the formula (I) are partly known.

Tetrahedron Letters 1967 (21), 1987-89 and Antibiotics + Chemotherapy 8, 342-348 (1958) /. Their use is to regulate plant growth however new.

Some of the phenylphosphonic acid derivatives which can be used according to the invention have not yet been described above; however, they can be produced in a simple manner by known T 11 17 1 processes (cf., for example, the publications mentioned above). They are obtained, for example, if one uses a benzene derivative of the formula in which R2 has the meaning given above, in the presence of an inert solvent, such as. B.

Acetonitrile, reacted with triethyl phosphite. The resulting Esters can be converted into the free acids by customary methods. From the latter the sodium salts can be prepared by known methods, e.g. B. by that the free acid is reacted in warm water with sodium hydrogen carbonate. the Active ingredients which can be used according to the invention intervene in the metabolism of plants and can therefore be used as growth regulators.

The following applies to the mode of action of plant growth regulators previous experience that an active ingredient is one or more different types Can have effects on plants.

The effects of the substances essentially depend on the point in time the application, based on the development stage of the seed or the plant as well as of the amounts of active ingredient applied to the plants or their environment and of the type of application. In any case, the crop plants should be growth regulators have a positive influence in the desired manner.

Substances regulating plant growth can be used, for example, to inhibit the vegetative plant growth can be used. Such inhibition of growth is Among other things, in the case of grasses of economic interest, because by damping of grass growth can e.g. the frequency of grass cuttings in ornamental gardens, parks and Sports facilities or roadsides are reduced. That is also important Inhibition of the growth of herbaceous and woody plants on roadsides and in near overhead power lines or, more generally, in areas where a strong Vegetation is undesirable.

The use of growth regulators for inhibition is also important the increase in length in grain, because through a stalk.

shortening the risk of twisting ("storage") of the plants reduced or eliminated before harvest. You can also use growth regulators cause a stalk reinforcement in grain, which also counteracts storage.

Inhibition of vegetative growth is possible in many cultivated plants a denser planting of the culture, so that an increased yield based on the soil area can be achieved.

Another mechanism of increasing yield is based on growth inhibitors ensure that the nutrients benefit to a greater extent the bloom and fruit formation come while vegetative growth is restricted.

Growth regulators can often also be used to promote the achieve vegetative growth. This is of great use when the vegetative Plant parts are harvested. However, vegetative growth can be promoted also at the same time lead to a promotion of generative growth, so that e.g.

more or larger fruits come to the training.

In some cases, increases in yield can also be achieved through an intervention in the vegetable metabolism can be achieved without any changes in the vegetative Make growth noticeable.

Growth regulators can also change the composition of the plants in order to bring about a better quality of the harvested products. For example, it is possible to determine the sugar content in sugar beet, sugar cane, Pineapples as well as citrus fruits increase or the protein content in soy or cereals to increase.

Under the influence of growth regulators it can lead to training parthenocarpic fruits come. The sex of the flowers can also be influenced will.

With growth regulators the production or the outflow can also be controlled positive influence of secondary plant substances. An example is stimulation called the latex flow in rubber trees.

During the growth of the plant can through the use of growth regulators also the lateral branching through a chemical breaking of the apical dominance be increased. There is interest in this, for example, when propagating plants from cuttings. However, it is also possible to inhibit the growth of the side shoots, e.g. in order to To prevent the formation of side shoots after decapitating tobacco plants and thus to promote leaf growth.

Under the influence of growth regulators, the leaf population of Plants are controlled so that a defoliation of the plants to a desired one Time is reached. Such defoliation is of interest to mechanical To facilitate harvesting, e.g. for wine or cotton, or to facilitate transpiration at a time when the plant is to be transplanted.

The premature fall of fruit can be prevented by using growth regulators impede. However, it is also possible to drop the fruit, for example in the case of fruit - to promote chemical thinning to a certain extent. Growth regulators can also be used to control crops at the time the harvest to reduce the force required to detach the fruit, so that mechanical or manual harvesting of the plants is possible Harvesting is facilitated.

Growth regulators can also be used to accelerate or also achieve a delay in the ripeness of the crop before or after the harvest. This is of particular advantage because it results in an optimal adaptation bring about the needs of the market. Furthermore, growth regulators can be used in some cases improve the color of the fruit.

In addition, with the help of growth regulators, a temporal Concentration of maturity can be achieved. This creates the prerequisites for this created that e.g. with tobacco, tomatoes or coffee, a complete mechanical or manual harvesting can be carried out in just one operation.

By using growth regulators, the seeds or Bud rest of the plants, i.e. the endogenous annual rhythm, can be influenced, see above that the plants, such as pineapples or ornamental plants in nurseries, at a time germinate, sprout or bloom when they are normally unwilling to do so demonstrate.

With growth regulators can also be achieved that the budding of buds or the germination of seeds is delayed, e.g.

in order to avoid damage from late frosts in areas at risk of frost avoid.

Growth regulators can also cause halophilia in crops produce. This creates the conditions for cultivation can be carried out by plants on salty soils.

With growth regulators, frost and drought resistance can also be achieved induced in plants.

The active compounds according to the invention can be used in the customary formulations such as solutions, emulsions, suspensions, powders, pastes and granulates. These are made in a known manner, e.g. B. by mixing the active ingredients liquefied pressurized liquids with extenders, i.e. liquid solvents Gases and / or solid carriers, optionally using surface-active substances Agents, that is to say emulsifiers and / or dispersants and / or foam-generating agents Means. In the case of the use of water as an extender, z. B. also organic Solvents can be used as co-solvents. As a liquid solvent are essentially: aromatics, such as xylene, toluene, benzene or alkylnaphthalenes, chlorinated aromatics or chlorinated aliphatic hydrocarbons, such as chlorobenzenes, Chlorethylene or methylene chloride, aliphatic hydrocarbons such as cyclohexane or paraffins, e.g. B. petroleum fractions, alcohols such as butanol or glycol and their Ethers and esters, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone or Cyclohexanone, strongly polar solvents such as dimethylformamide and dimethyl sulfoxide, as well as water; with liquefied gaseous extenders or carriers such liquids are meant which are at normal temperature and under normal pressure are gaseous, e.g. B. aerosol propellants such as dichlorodifluoromethane or trichlorofluoromethane; as solid carrier materials: natural stone powders such as kaolins, clays, talc, Chalk, quartz, attapulgite, montmorillonite or diatomaceous earth and synthetic rock flour, such as finely divided silica, aluminum oxide and silicates; as emulsifier: non-ionic and anionic emulsifiers, such as polyoxyethylene fatty acid esters, polyoxyethylene fatty alcohol ethers, e.g. alkylaryl polyglycol ethers, alkyl sulfonates, alkyl sulfates, aryl sulfonates and Protein hydrolysates; as a dispersant: e.g. B. Lignin sulphite liquors and methyl cellulose.

The active compounds according to the invention can be mixed in the formulations with other known active ingredients, such as fungicides, insecticides, acaricides and herbicides, as well as mixed with fertilizers.

The formulations generally contain between 0.1 and 95 percent by weight Active ingredient, preferably between 0.1 and 90 percent by weight.

The active ingredients can be used as such, in the form of their formulations or the use forms prepared therefrom, such as ready-to-use solutions, emulsifiable Concentrates, emulsions, foams, suspensions, wettable powders, pastes, soluble powders, Dusts and granules. The application happens in the usual Way, e.g. by pouring, spraying, atomizing, scattering, dusting, foaming, Gassing, etc. It is also possible to use the active ingredients using the ultra-low-volume method to apply plants or parts of plants with the active ingredient preparation or the To coat the active ingredient itself or the Wiristoffpreparation or the active ingredient inject yourself into the ground. It can also treat the seeds of the plant will.

The amount of active ingredient used can vary within a relatively wide range will. In general, between 0.01 and 50 per hectare of land is used kg, preferably between 0.05 and 10 kg of active ingredient.

For the application time, the use of the growth regulators applies is carried out in a preferred period, the exact delimitation of which is based on the climatic and vegetative conditions.

In the following examples, the activity of the invention Substances presented as growth regulators without the possibility of further application to exclude as growth regulators.

Example A Growth inhibition / Gers te solvent: 10 parts by weight of methanol Emulsifier: 2 parts by weight of polyethylene sorbitan monolaurate Appropriate active ingredient preparation is mixed 1 part by weight of active ingredient with the specified amounts of solvent and emulsifier and fill up with water to the desired Concentration on.

Young barley plants are treated with the preparation of the active compound in the 2-leaf stage sprayed dripping wet. After the untreated control plants have reached a height of have reached about 60 cm, the increment is measured for all plants and the Growth inhibition calculated in * of the growth of the control plants. It means 100 % the standstill of the growth and 0 * a growth corresponding to that of the control plants.

Active ingredients, active ingredient concentrations and results are based on the following Table.

Table A Inhibition of growth / barley Active ingredient active ingredient con- growth inhibition centering in% in% (Control) O OH 3 OH 0.05 5 (known) CH2 CH3 0 CB, -CO-NH-N, 0.05 CH, CHZ-COOH (known) 0.05 40 2 102 (4) Tab 1 le A (continued) Inhibition of growth / barley Active ingredient active ingredient con- I growth inhibition centering in% in% 0 II P s0 | 0.05 1 30 Cl a S 5 (1) Example B Growth inhibition / wheat Solvent: 10 parts by weight of methanol Emulsifier: 2 parts by weight of polyethylene sorbitan monolaurate To produce an appropriate active ingredient preparation, 1 part by weight of active ingredient is mixed with the stated amounts of solvent and emulsifier and made up to the desired concentration with water.

Young 'icing plants are in the 2-leaf stage with the active compound preparation sprayed dripping wet. After the untreated control plants had an axial height of have reached about 60 cm, the increment is measured for all plants and the Inhibition of growth in where the growth of the control plants is calculated. It means 100 % the stagnation of the growth and 0 / o a growth corresponding to that of the untreated Control plants.

Active ingredients, active ingredient concentrations and results are based on the following Table.

Table B Inhibition of growth / wheat Active ingredient active ingredient con- growth inhibition centering in% in% (Control) O OH 3 CH2-CO-WH-IDw 0.05 0 CH3 CH2-COGH (known) OH Ir 0.05 40 NO2 (3) Example C Influencing growth / chrysanthemums Solvent: 10 parts by weight of methanol Emulsifier: 2 parts by weight of polyethylene sorbitan monolaurate To produce an appropriate preparation of active ingredient, 1 part by weight of active ingredient is mixed with the stated amounts of solvent and emulsifier and made up to the desired concentration with water.

10 cm high chrysanthemum cuttings are prepared with the active ingredient sprayed dripping wet. After 3 weeks, the increment is measured and the influence on the growth calculated in% of the growth of the control plants. O% means growth, which corresponds to that of the control plants. Positive values indicate one Promotion of growth compared to the control plants while negative values correspond accordingly indicate an inhibition of growth.

Active ingredients, active ingredient concentrations and results are based on the following Table.

Table C Growth control / chrysanthemums Active ingredient active ingredient centering in% sung in% (Control) O 0 II OH P (oH 0.1 +30 ° 2 (3) 0 II OC2H5 Cl <OC2H5 N ° 2 0.1 -60 (1) Preparation examples Example 1 A mixture of 202.5 g (1 mol) of 4-chloro-1,2-dinitrobenzene, 1 liter of acetonitrile and 225 g (1.65 mol) of triethyl phosphite is refluxed until no more ethyl nitrite escapes (about 5 hours). The solvent is then distilled off in vacuo. The remaining residue is distilled in vacuo. In this way, 250 g (86% of theory) of a mixture of 4-chloro- and 5-chloro-2-nitrophenylphosphonic acid diethyl ester are obtained in the form of yellow crystals with a melting point of 560.degree. The boiling point is 158-161 ° C / 0.11 Torr.

Example 2 According to the information in Example 1, the 2-nitrophenylphosphonic acid diethyl ester is obtained by reacting triethyl phosphite with 1,2-dinitrobenzene.

Yield: 68% of theory Melting point: 49 ° C. Example 3 200 g of diethyl 2-nitrophenylphosphonate are refluxed in 1 liter of concentrated hydrochloric acid for 5 hours. The water is then distilled off in vacuo, the residue is triturated with ether and filtered off with suction. 122 g (78% of theory) of 2-nitrophenylphosphonic acid are thus obtained in the form of colorless crystals with a melting point of 199-2000C.

Example 4 20.3 g (0.1 mol) of 2-nitrophenylphosphonic acid are dissolved together with 8.4 g (0.1 mol) of sodium hydrogen carbonate in 200 ml of warm water. After filtration, the solvent is distilled off in vacuo. 22.5 g (calculated amount) of 2-nitrophenylphosphonic acid monosodium salt remain in the form of colorless crystals with a melting point of 2500C.

Claims (5)

Claims 1. Agent for regulating plant growth, characterized by a content of at least one phenylphosphonic acid derivative of the formula in which R stands for hydrogen or ethyl, R1 stands for hydrogen, ethyl or a sodium atom and R2 stands for hydrogen or chlorine. 2. Means for inhibiting growth and for influencing the habitus of higher plants, characterized in that there is at least one phenylphosphonic acid derivative according to claim 1 contains. 3. A method for regulating plant growth, characterized in that that one phenylphosphonic acid derivatives according to claim 1 on the plants or their Lets living space act. 4. Use of phenylphosphonic acid derivatives according to claim 1 for Regulation of plant growth. 5. Process for the production of plant growth regulators, characterized in that one phenylphosphonic acid derivatives according to claim 1 with Diluents and / or surfactants mixed together.