COMPOSITIONS AND METHOD FOR REGULATING SOYBEAN PLANT GROWTH UTILIZING SUBSTITUTED BENZAZOLYLTHIOALKANOIC ACIDS

Abstract: This invention relates to a method of regulating the growth of leguminous plants which comprises applying to the plant locus a plant growth regulating effective amount of a compound having the general formula wherein X is selected from the group consisting of oxygen, sulfur and -NH; R is hydrogen, halogen or lower alkyl; R₁ is selected from the group consisting of and CN; R₂ is selected from the group consisting of hydrogen, lower alkyl and agriculturally acceptable cations; R₃ and R₄ are independently selected from the group consisting of hydro­ gen and lower alkyl; and n is an integer from 1 to 3, with the proviso that when R₁ is n cannot be 2. This invention also relates to a plant growth regulat­ ing composition which comprises from about 5 to about 95 parts by weight of a compound having the above general formula, the remaining parts being comprised of one or more suitable adjuvants, carriers and/or diluents.

Description: SUBSTITUTED BENZAZOLYLTHIOALKANOIC ACIDS AS PLANT GROWTH REGULANTS This invention relates to the use of certain 2-benzothiazolylthioalkanoic acids, 2-benzoxazolylthioalkanoic acids and 2-benzimidazolylthioalkanoic acids and derivatives thereof to regulate the growth of leguminous plants. More specifically, this invention relates to a method of regulating the growth of leguminous plants which comprises applying to the plant locus a plant growth regulating effective amount of a compound characterized in that the said compound has the general formula EMI1.1 wherein X is selected from the group consisting of oxygen, sulfur and -NH; R is hydrogen, halogen or lower alkyl; R1 is selected from the group consisting of EMI1.2 R2 is selected from the group consisting of hydrogen, lower alkyl and agriculturally acceptable cations; R3 and R4 are independently selected from the group consisting of hydrogen and lower alkyl; and n is an integer from 1 to 3, with the proviso that when R1 is EMI1.3 n cannot be 2. The invention also provides a plant growth regulating composition which comprises from about 5 to about 95 parts by weight of a compound, the remaining parts being comprised of one or more suitable adjuvants, carriers and/or diluents, characterized in that said compound has the general formula EMI2.1 wherein X is selected from the group consisting of oxygen, sulfur and -NH; R is hydrogen, halogen or lower alkyl; R1 is selected from the group consisting of EMI2.2 R2 is selected from the group consisting of hydrogen, lower alkyl and agriculturally acceptable cations; R3 and R4 are independently selected from the group consisting of hydrogen and lower alkyl; and n is an integer from 1 to 3, with the proviso that when R7 is EMI2.3 n cannot be 21. Preferred are those compounds in which R is hydrogen or chloro, especially hydrogen. R2 is preferably methyl or ethyl and R3 is preferably hydrogen. As used herein, the term "lower alkyl" means those alkyl groups, branched as well as unbranched, having up to 5 carbon atoms. The term "agriculturally acceptable cations" is understood to mean those cations normally used to form the salt of the free acid and include, but are not limited to, alkali metal, alkaline earth, ammonium and substituted ammonium cat ions. Illustrative of the plant growth regulating compounds of the present invention are 2-benzothiazolylthioacetic acid; 5-chloro-2-benzothiazolylthioacetic acid; 2-benzoxazolylthioacetic acid; 2-benzimidazolylthioacetic acid; ethyl 2-benzothiazolylthioacetate; ethyl 2-benzimidazolylthioacetate; ethyl 2-benzoxazolylthioacetate; methyl 2-benzothiazolylthioacetate; methyl 2 -benzoxazolylthioacetate; methyl 2-benzimidazolylthioacetate; 2-benzothiazolylthioacetamide; 5-chloro-2-benzothiazolylthioacetamide; 2 benz oxaz olylt hioacet amid e; 5-chloro-N-methyl-2-benzothiazolylthioacetamide; N-methyl-2-benzimidazolylthioacetamide; 2-benzoxazolylthioacetonitrile; 2-benzothiazolylthioacetonitrile; 2-benzimidazolylthioacet6nitrlle; 2-benzothiazolylthiobutyronitrile; 2-benzoxazolylthiobutyronitrile; 2-benzimidazolylthiobutyronitrile; and 5-chloro-2-benzothiazolylthiobutyronitrile. In accordance with the novel aspects of the present invention, the compounds of the foregoing formula are effective plant growth regulants, especially in the regulation of leguminous plants. The term "plant regulant" or "plant growth regulant", as employed in this application, connotes a material which serves to modify the normal sequential development of a treated plant to agricultural maturity. Such modification may result from the effect of material on the physiological processes of the plant or from the effect of said material on the morphology of the plant. It should additionally be recognized that mod.ifications may also result from a combination or sequence of both physiological and morphological factors. Modifying effects of a plant regulant are probably most readily observed as changes in the size, shape, color or texture of the treated plant or any of its parts. Similarly, changes in the quantity of the plant fruit or flowers are also quite apparent from simple, visual inspection. The above changes may be characterized as an acceleration or retardation of plant growth, such as an increase or decrease in dry weight accumulation, stature reduction, leaf or canopy alteration, increased branc.hing, terminal inhibition, increased flowering or fruit set. Modifications in the normal sequential development of a treated plant to agricultural maturity may also be manifested by reduced transpiration or increased carbohydrate deposition or protein content. It is to be understood that each response may occur in conjunction with other responses, but may occur separately. For example, depending upon various factors realized by those skilled in the art to effect activity, the data illustrated below demonstrates that the compounds of the present invention sometimes alter the leaf morphology even though the plants are not reduced in stature. Alteration of the leaf morphology of leguminous plants is important because leguminous plants have canopies that effectively inhibit sunlight from reaching the lower leaves. For example, only about 50% of a soybean plant's leaves intercept light for photosynthesis. Approximately 85% of the light is absorbed by the outer layer of leaves. Many researchers feel that by altering the morphology of the leaves such that the canopy is altered, light may fall more deeply into the canopy, and yields could be increased. (veer, in "Field Crop Abstracts", Volume 21, No. 4, pages 313-317, states that "greater light penetration, resulting in greater amount of the [soybean] plant canopy having a light intensity above 150 f.c., generally led to higher seed yields." Johnson et al, in "Crop Science", Volume 9, pages 577-581, states that "adding light increased the yields of bottom, middle and top canopy positions of [soybean] plants 30, 20 and 2%, respectively." Thus, it would be highly beneficial if a method was found whereby the leaves of such plants could be altered such that a greater number of leaves could be nlluminated. The regulation of plants in accordance with the instant invention does not include the total inhibition or the killing of such plants. Although phytotoxic amounts of the materials disclosed herein might be employed to exert a herbicidal (killing) action, it is contemplated herein to employ only plant regulating amounts of such materials in order to modify the normal sequential development of the treated plant to agricultural maturity. The application of a plant regulating amount may be applied to plants in sequence at various stages of the plants' development to obtain various desirable responses. As may be expected, and as is apparent to those skilled in the art, such plant regulating amount will vary, not only with the material selected, but also with the modifying effect desired, the species of plant and its stage of development, the plant growth medium and whether a permanent or transitory effect is sought. The acids of the foregoing formula (I) may prepared by reaction of the appropriate 2-mercaptobenzoxazole, 2mercaptobenzothiazole or 2-mercaptobenzimidazole with a brominated carboxylic acid and sodium hydroxide. For sake of clarity, the above reaction procedure is illustrated by the reaction scheme below: EMI5.1 The compounds identified in Table I, below, were prepared in accordance with the above reaction scheme as follows. To a stirred solution contain;n.g 35 g (0.25 mole) of bromoacetic acid in 100 ml. of water, 18.6 g !0.125 mole) of potassium carbonate is added in small portions until a pH of 8 is obtained. This solution is added to a stirred solution containing 0.25 moles of the appropriate mercaptan, 20 g (".25 mole) of 50% aqueous sodium hydroxide and 200 ml. of water. The stirred solution is heated at reflux for 6 hours. After cooling to 250C., 30 g (0.3 mole) of concentrated hydrochloric acid in 500 ml. of water is added dropwise until pH of 2 is obtained. After stirring at 25-300C for 15 minutes, the solid is collected by filtration, washed with water until neutral to litmus and air-dried at 500C. The data are summarized in Table I. Table I EMI7.1 Compound Percent Percent N Percent S Number R X n m.p. C. Yield Calc d. Found Calc'd. Found 1 H S 1 153-5 99 6.22 6.10 28.47 28.57 2 5-Cl S 1 168-170 95 5,39 5.26 24.69 24.52 3 H O 1 164-5(a) 99 6.70 6.61 15.33 15.59 4 H NH -1 204-6 93 13.45 13.44 15.40 15.30 (a) Recrystallization from isopropyl alcohol. Esters are prepared in accordance with the reaction scheme below by reacting the appropriate 2-mercaptobenzoxazole, 2-mercaptobenzothiazole or 2-mercaptobenzimidazole with the appropriate brominated ester under basic conditions as follows: EMI8.1 The compounds identified in Tables II and III, below, were prepared in accordance with the above reaction scheme as follows. To a stirred solution containing 0.1 mole of the appropriate mercaptan, 6.6 g (0.1 mole) of 858 potassium hydroxide, and 200 ml. of ethanol, 17.8 g (0.1 mole) of 94% ethyl bromoacetate is added in one portion. The stirred reaction mixture is heated at reflux for 24 hours. After cooling to 5 C., 800 grams of ice water is added and stirring continued at 0-100C. for one hour. The solid is collected by filtration, washed with cold water until neutral to litmus and airdried at 25-30 C. The data are summarized in Table II. Table II EMI9.1 Compound Percent Percent C Percent H Percent N Percent S No. X R2 n m.p. C. Yield Calc'd. Found Calc'd. Found Calc'd. Found Calc'd. Found 5 S -C2H5 1 39-40 95 52.15 52.10 4,38 4,38 5.53 5.56 25.31 25.36 6 NH -C2H5 1 92-3(a) 85 55.91 55.73 5.12 5.18 11.86 11.77 13.57 13.45 7 O -C2H5 1 32 93 55.68 55.84 4,67 4.68 5.90 5.90 13.51 13.47 (a) Recrystallization from heptane-ethyl alcohol. To a stirred solution containing (0.1 mole) of the appropriate mercaptan, 21.6 g (0.1 mole) of 25% sodium methylate in methyl alcohol and 200 ml. of methyl alcohol, 16.8 g (0.1 mole) of methyl bromoacetate is added in one portion. The stirred reaction mixture is heated at reflux for 24 hours. The rest of the procedure is identical as that described above to prepare the ethyl esters. The data are summarized in Table III. Table III EMI11.1 Compound Percent Percent C Percent H Percent N Percent S No. X R2 n m.p. C. Yield Calc'd. Found Calc'd. Found Calc'd. Found Calc'd. Found 8 S -C2H5 1 73-4(a) 99 50.19 50.27 3,79 3,80 5.85 5.85 26.80 26.68 9 O -C2H5 1 53-4 81 53.80 53.66 4.06 4.10 6.27 6.27 14.36 14.32 10 NH -C2H5 1 110-11(a) 87 54.04 54.16 4,54 4.61 12.60 12.60 14.43 14.40 (a) Recrystallization from heptane-ethyl alcohol. Am ides of the foregoing formula are prepared by reaction of the appropriate 2-mercaptobenzoxazole, 2 mercaptobenz othiaz ol e or 2mercaptobenz imidaz ol e with the appropriate chlorinated amide and potassium hydroxide in accordance with the following reaction scheme: EMI12.1 The compounds identified in Table IV, below, have been prepared in accordance with the above procedure as follows. To a stirred solution containing 0.2 mole of the appropriate mercaptan, 13.2 g (0.2 mole) of 85% potassium hydroxide, 300 ml. of acetone and 20 ml. of water, 0.2 mole of 2-chloroacetamide or 2-chloro N-methylacet.lmide is added in one portion. The stirred reaction mixture is heated at reflux for eight hours and at 25-300C. for 18 hours. After the addition of 800 ml. of water, the reaction mixture is stirred at 25-30 C. for 30 minutes. The solid is collected by filtration, washed with water until neutral to litmus and air-dried at 25-300C. The data are summarized in Table IV. Table IV EMI13.1 Com- Perpound cent Percent C Percent H Percent N Percent S No. R X n R3 R4 m.p. C. Yield Calc'd. Found Calc'd. Found Calc'd. Found Calc'd. Found 11 H S 1 H -H 147-8(a) 83 --- --- --- --- 12.49 12.10 --- -- 12 5-Cl S 1 H -H 187-8(b) 91 41.78 41.62 2,73 2.69 --- --- --- -- 13 H O 1 H -H 163-4(a) 80 --- --- --- --- 13.45 13.59 15.40 15.58 14 5-Cl S 1 H -CH3 138-9(c) 78 44.03 44.05 3.33 3.36 10.27 10.29 23.51 23.45 15 H NH 1 H -CH3 178-9(a) 69 54.28 54.25 5.01 5.07 18,99 18.96 14.49 14.40 (a) Recrystallization from isopropyl alcohol. (b) Rectystallization from methyl alcohol. (c) Rectystallization from isopropyl alcohol - heptane. Nitriles of the foregoing formula are prepared by reacting the appropriate 2-mercaptobenzoxazole, 2mercaptobenzothiazole or 2-mercaptobenz imidazole with potassium hydroxide and chloroacetonitrile, chloropropionitrile or chlorobutyronitrile in accordance with the following reaction scheme: EMI14.1 In accordance with the above procedure, 2-benzoxazolethioacetonitrile (Compound No. 16) has been prepared by adding 8.4 g (0.11 mole) of chloroacetonitrile in one portion to a stirred solution containing 0.1 mole of 2-mercaptobenzoxazole, 6.6 g (0.1 mole) of 85% potassium hydroxide, 200 ml. of acetone and 10 ml. of water. An exothermic reaction set in causing a temperature rise from 25 to 500C. The stirred reaction mixture is heated at reflux for six hours. After cooling to 50C., 800 grams of ice water is added and stirring continued at 0-100C. for 30 minutes. The solid is collected by filtration, washed with water until neutral to litmus and air-dried at 25-30 C. Compound No. 16 having the structure EMI14.2 was obtained in 92% yield, m.p. 97-980C. from isopropyl alcohol. Anal. Calc'd: C, 56.83; H, 3.18; N, 14.73; S, 16.86. Found: C, 56.80; H, 3.19; N, 14.70; S, 16.86. Similarly, the compounds identified in Table V have been prepared. To a stirred solution containing 0.2 mole of 2-mercaptobenzothiazoie or 2 ercaptobenz imidazole, 13.2 grams (0.2 mole) of potassium hydroxide and 500 ml. of water, 15.2 grams (0.2 mole) of chloroacetonitrile is added in one portion. After stirring at 25-300C. for three hours, the solid is collected by filtration, washed with water until neutral to litmus and air-dried at 25-300C. The data are summarized in Table V. Table V EMI16.1 Com- Perpound cent Percent C Percent H Percent N Percent S No. R n X m.p. C. Yield Calc'd. Found Calc'd. Found Calc'd. Found Calc'd. Found 17 H 1 S 81-2(b) 95 --- --- --- --- 13.58 13.51 31.09 31.38 18 H 1 NH 160-1(a) 90 57.12 57.07 3.73 3.74 22.21 22.19 16.94 16.97 (a) Recrystallization from isopropyl alcohol. (b) Recrystallization from heptane. In a similar manner, the compounds identified in Table VI have been prepared. To a stirred solution containing 0.2 mole of the appropriate mercaptan, 13.2 g (0.2 mole) of 85% potassium hydroxide, 200 ml. of dimethyl formamide and 20 ml. of water, 20.7 grams (0.2 mole) of 4-chlorobutyronitrile is added in one portion. The stirred reaction mixture is heated at 90-1000C. for six hours and at 25-30 C. for 18 hours. To prepare Compound Nos. 19 and 20, 500 ml. of water and 600 ml. of ethyl ether are added and stirring continued at 25-30 C. for 15 minutes. The separated ether layer is washed with water until neutral to litmus and dried over sodium sulfate. The ether is removed in vacuo at a maximum temperature of 80-90"C. at 1-2 zm. To prepare Compound Nos. 21 and 22, 800 grams of ice water is added and stirring continued at 10-200C. for 30 minutes. The solid is collected by filtration, washed with water until neutral to litmus and air-dried at 25-300C. The data are summarized in Table VI. Table VI EMI18.1 Compound Percent Percent N Percent S Percent Cl No. R X n m.p. C. Yield ND25 Calc'd. Found Calc'd. Found Calc'd. Found 19 H S 3 amber 90 1.6405 11.96 11.85 27.37 17.16 --- -- liquid 20 H O 3 amber 94 1.5903 12.84 12.93 14.69 14.84 --- -- liquid 21 H NH 3 137-8(a) 83 --- 19.34 19.43 14.76 14.87 --- --22 5-Cl S 3 74-5(b) 98 --- 10.42 10.52 23.86 24.05 13.19 13.09 (a) Recrystallization from ethyl acetate. (b) Recrystallization from heptane-isopropyl alcohol. To illustrate the variety of regulatory responses observed, the compounds of the invention were tested in accordance with the following procedure. A number of soybean plants are grown from seeds in plastic pots in the greenhouse for a period of one week at which time the plants are thinned to one plant per pot. When the second trifoliate leaf is fully expanded, the plants are treated with a solution of the active ingredient in acetone and water. Aqueous Tween 20 is used as a surfactant. When the fifth trifoliate leaf of the control is fully expanded, the treated plants are compared with the nontreated control plants and the observations recorded. The following observations were made when soybeans were treated at the indicated rates with the compounds of the foregoing formula. Compound Rate Number (kg/ha) Observations 1 2.8 Stature reduction, inhibition of dry weight, slight leaf burn, leaf distor tion, leaf alteration, leaf inhibition, altered canopy. 0.56 Leaf alteration, leaf inhibition, altered canopy. 0.112 No response. 5 2.8 Stature reduction, inhibition of dry weight, slight leaf burn, leaf altera tion of old and new growth, leaf inhi bit ion, altered canopy. 0. 56 Stature reduction, inhibition of dry weight, leaf alteration of old and new growth, leaf inhibition, altered canopy. 0.112 Leaf alteration of new growth. 11 2.8 Stature reduction, inhibition of dry weight, leaf alteration, slight leaf burn, leaf distortion, leaf inhibition, altered canopy. 0.56 Leaf alteration, leaf inhibition, altered canopy. 0.112 No response. Compound Rate Number (kg/ha) Observations 4 2.8 Stature reduction, leaf alteration of old and new growth, leaf inhibition, altered canopy. 0.56 Stimulation of dry weight. 0.112 No response. 3 2.8 Inhibition of dry weight, slight leaf burn, leaf distortion, leaf alteration. 0.56 No response. 0.112 No response. 17 2.8 Inhibition of dry weight, slight leaf burn, stem distortion, leaf distortion, leaf alteration, leaf inhibition, inhi bition of apical development. 0.56 Inhibition of dry weight, stem distortion, leaf inhibition, leaf alteration of new growth. 0.112 Inhibition of dry weight. 22 2.8 Stature reduction, inhibition of dry weight, moderate leaf burn, chlorosis, leaf alteration, altered canopy. 0.56 Inhibition of dry weight, slight leaf burn, chlorosis. 0.112 Inhibition of dry weight. 8 2.8 Stature reduction, inhibition of dry weight, moderate leaf burn, stem distor tion, leaf distortion, leaf alteration, inhibition of apical growth. 0.56 Stature reduction, inhibition of dry weight, slight leaf burn, stem distortion, leaf alteration, leaf inhibition, inhi bition of apical development. 0.112 Inhibition of dry weight. Compound Rate Number (kg/ha) Observations 9 2.8 Stature reduction, inhibition of dry weight, slight leaf burn, leaf distor tion, leaf inhibition, altered canopy, inhibition of apical development. 0.56 No response. 0.112 No response. 10 2.8 Stature reduction, inhibition of dry weight, slight leaf burn, leaf altera tion, leaf inhibition, altered canopy, inhibition of apical development. 0.56 No response. 0.112 No response. 6 2.8 Stature reduction, inhibition of dry weight, leaf alteration of old and new growth, leaf inhibition, altered canopy. 0.56 Inhibition of dry weight, leaf altera tion of old and new growth. 0.112 Leaf alteration of old and rew growth. 15 2.8 Stature reduction, inhibition of dry weight, slight leaf burn, leaf distor tion, leaf alteration of old and new growth, leaf inhibition. 0.56 Inhibition of dry weight, leaf alteration of old and new growth, altered canopy. 0.112 Inhibition of dry weight, leaf alteration of old and new growth. Compound Rate Number (kg/ha) Observations 19 2.8 Stature reduction, inhibition of dry weight, slight leaf burn, leaf distor tion, leaf alteration, altered canopy. 0.56 No response. 0.112 No response. 12 2.8 Inhibition of dry weight. 0.56 Inhibition of dry weight. 0.112 inhibition of dry weight. The compounds of the invention were further tested as follows. A number of soybean plants are grown from seeds in aluminum pans in the greenhouse for a period of approximately 1 week to the primary leaf stage. The plants are thinned to three uniform plants in each pan and the height of each plant in the pan is measured to the terminal bud and the average height is noted. One pan containing three soybean plants is used for each chemical treatment and three pans are not treated and used as a control. The composition formulated with acetone and Tween 20 as a surfactant is then applied to the pan of growing plants by overhead spray at a rate equivalent to the desired rate of active ingredient per acre. The treated pans, along with the control pans, are maintained in a greenhouse and watered from below on a sand bench and fertilized with a uniform portion of a water-soluble balanced fertilizer. Two weeks after application of the chemical, the average height of the soybean plants in the treated pan is again measured as above and the difference in the average height before and 2 weeks after application represents the increase in the development of the treated pans. This development in growth of the treated plants is compared to the average increase in growth of the plants in the control pans during the sam period of time. A variation of 25% or more in the development of at least two-thirds of the treated plants when compared to the development of the control plants demonstrates that the chemical is an effective plant regulant. Thus, a chemical is considered active when the treated plants manifest a decrease in growth of at least 25% less than that of the control plants, i.e., stature reduction, or an increase in growth in excess of 25% of that of the control plants, i.e., growth stimulation. The following results and observations were made when the benzothiazolines of the invention were utilized as the active ingredient at several rates. Compound Rate Number (kg/ha) Observations 11 6.72 Stature reduction, stem distortion, slight leaf burn, altered canopy, stimulation of axillary buds. 3.36 Stature reduction, leaf alteration, altered canopy, stimulation of axillary buds. 3.36 Stature reduction, stem distortion, altered canopy, stimulation of axillary buds. 1.34 Leaf alteration. 0.67 Leaf alteration. 17 6.72 Stature reduction, slight leaf burn, stimulation of axillary buds, inhibition of apical development. 3.36 Stature reduction, slight leaf burn, stimulation of axillary buds, inhibition of apical development. 1.34 No response. ;8 6.72 Stature reduction, slight leaf burn, leaf alteration. 3.36 No response. Compound Rate Number (kg/ha) Observations - 13 6.72 Chlorosis, leaf alteration, altered canopy, stimulation of axillary buds. 6.72 Chlorosis, leaf alteration, altered canopy, stimulation of axillary buds, slight leaf burn. 3.36 Leaf alteration, altered canopy, stimulation of axillary buds. 1.34 Stimulation of axillary buds. 20 6.72 Slight leaf burn, leaf distortion, stimulation of axillary buds. 21 6.72 Slight leaf burn, leaf distortion. 2 6.72 Stature reduction, slight leaf burn, defoliation, altered canopy. 3.36 Stature reduction, slight leaf burn, defoliation, leaf inhibition. 1.34 Stature reduction, slight leaf burn, stimulation of axillary buds. 0.67 Stature reduction, altered canopy, stimulation of axillary buds. 0.67 Stature reduction, altered canopy, stimulation of axillary buds, slight leaf burn. 0.36 Altered canopy, slight leaf burn. 0.112 No response. 22 6.72 No response. 16 6.72 Altered canopy, leaf alteration, stimu lation of axillary buds. 6.72 Stature reduction, slight leaf burn, inhibition of apical development, stimu lation of axillary buds. 3.3 6 Altered canopy, leaf alteration, stimu lation of axillary buds. 1.34 Leaf alteration. Compound Rate Number (kg/ha) Observations 19 6.72 Stature reduction, slight leaf burn, defoliation. 3.36 Stature reduction, slight leaf burn, defoliation. 1.34 Stimulation of axillary buds, slight leaf burn. 12 6.72 Altered canopy, stimulation of axillary buds. 6.72 Leaf distortion, slight leaf burn, stimulation of axillary buds. 3.36 Stimulation of axillary buds. 1.34 No response. Further tests were conducted as follows. Individual soybean plants are grown from seed in 6-inch pots containing a good grade of top soil. Two pots of 6-week old plants (5-6 trifoliate stage) are used for each application oi the chemical. An overhead spray of an aqueous composition of the chemical is applied to the pots at an equivalent rate as indicated below. Two to four sets of plants which received no chemical application are included and serve as controls. All of the pots are maintained under good growing conditions and are watered and are fertilized with a uniform amount of water-soluble balanced fertilizer. Two weeks after the application of the chemical, the growth responses of the treated plants are compared with that of the control plants. The total height of the plant is measured to the tip of the terminal bud. A variation of 15% in the average total height of the treated plants, when compared to the average total height of the control plants, demonstrate that the chemical is an effective plant growth requlator. Observations made utilizing this proceaure are summarized as follows. Compound Rate Number (kg/ha) Observations 11 2.8 Stature reduction, leaf distortion. 1.12 Stature reduction, leaf distortion, leaf alteration. 16 2.8 Leaf distortion, leaf alteration, delayed pod set, inhibited pod set. 1.12 Stature reduction, leaf alteration. 0.56 No response. From the above data, it can be seen that the compounds of the present invention are especially effective in reducing the stature of the soybean plant as well as altering the leaf morphology. In practicing the plant growth regulating methods of this invention, the active ingredient can be used alone or in combination with a material referred to in the art as an adjuvant in liquid or solid form. The plant growth regulating compositions of this invention are prepared by admixing the active ingredient with an adjuvant including diluents, extenders, carriers and conditioning agents to provide composit ions in the form of inely-divided particulate solids, granules, pellets, wettable powd rs, dusts, solutions and aqueous dispersions or emulsions. Thus, the active ingredient can be used with an adjuvant such as a finely-divided parts culate solid, a solvent liquid of organic origin, water, a wetting agent, dispersing agent, or emulsifying agent or any suitable combination of these. When applying the active ingredient to leguminous plants, useful finelydivided solid carriers and extenders include, for example, the talcs, clays, pumice, silica, diatomaceous earth, quartz, Fullers earth, sulfur, powdered cork, powdered woos, walnut flour, chalk, tobacco dust, charcoal and the 1 uke. Typical liquid diluents u.seful in applying the active ingredient to leguminous plants include, for example, Stoddard solvent, acetone, alcohols, glycols, ethyl acetate, benzene and the like. Such leguminous plant growth regulating compositions, particularly liquids and wettable powders, usually contain as a conditioning agent one or more surface-active agents in amounts sufficient to render a given composition readily dispersible in water or in oil. By the term "surface-active agent", it is understood that wetting agents, dispersing agents, suspending agents and emulsifying agents are included therein. Such surface-active agents are well known and reference is made to U.S. Patent No. 2,547,724, columns 3 and 4, for detailed examples of the same. Compositions of this invention generally contain from about 5 to 95 parts active ingredient, about 1 to 50 parts surface-active agent and about 4 to 94 parts solvent, all parts being by weight based on the total weight of the composition. Desirable modification of leguminous plants may be achieved by applying the above-described plant regulants to the plant locus. The term "plant locus" is understood herein to include the plant growing medium, such as the soil, as well as the seeds, emerging seedlings, roots, stems, leaves, flowers, fruits or other plant parts. The application of liquid and particulate solid compositions of the active ingredient can be carried out by conventional techniques utilizing, for example, spreaders, power dusters, boom and hand sprayers and spray dusters. The compositions can also be applied from airplanes as a dust or spray. If desired, application of the compositions of the invention to leguminous plants can be accomplished by incorporating the compositions in the soil or other media in the area where modification of the plants is desired. In selecting the appropriate non-toxic rate of application of the active ingredient to leguminous plants, it will be recognized that precise rates will also be dependent upon the mode of application, such as soil incorporation, band application, pre-plant seed treatment, result desired and various other factors known to those skilled in the art. In applications to the soil habitat of germinant seeds, emerging seedlings, and established vegetation for the regulation of plant growth, the active ingredients are applied in amounts of from about 0.056 to 22.4 kilos/hectare. Foliar application is particularly advantageous and is preferred especially from about 0.112 to about 6.7 kilos/hectare. Although this invention has been described with respect to specific modifications, the details thereof are not to be construed as limitations, for it will be apparent that various equivalents, changes and modifications may be resorted to without departing from the spirit and scope thereof and it is understood that such equivalent embodiments are intended to be included herein

Claims: CLAIMS. 1. A method of regulating the growth of leguminous plants which comprises applying to the plant locus a plant growth regulating effective amount of a compound characterized in that the said compound has the general formula EMI29.1 wherein X is selected from the group consisting of oxygen, sulfur and -NH; R is hydrogen, halogen or lower alkyl; R1 is selected from the group consisting of EMI29.2 R2 is selected from the group consisting of hydrogen, lower alkyl and agriculturally acceptable cat ions; R3 and R4 are independently selected from the group consisting of hydrogen and lower alkyl; and n is an integer from 1 to 3, with the proviso that when R, is EMI29.3 n cannot be 2. 2. A method according to Claim 1 wherein X is sulfur. 3. A method according to Claim 1 wherein X is oxygen. 4. A method according to Claim 1 wherein X is -NH. . 5. A method according to Claim 1 wherein n is 1 or 3. 6. A method according to Claim I wherein R1 is EMI30.1 7. A method according to Claim 6 whereir R2 is hydrogen. 8. A method according to Claim 1 wherein R1 is EMI30.2 9. A method according to Claim 8 wherein R3 is hydrogen. 10. A method according to Claim 9 wherein R4 is methyl. 11. A method according to Claim I wherein R1 is CN. 12. A plant growth regulating composition which comprises from about 5 to about 95 parts by weight of a compound, the remaining parts being comprised of one or more suitable adjuvants, carriers and/or diluents, characterized in that said compound has the general formula EMI31.1 wherein X is selected from the group consisting of oxygen, sulfur and -NH; R is hydrogen, halogen. or lower alkyl; R1 is selected from the group consistinq of EMI31.2 R2 is selected from the group consisting of hydrogen, lower alkyl and agriculturally acceptable cations; R3 and R4 are independently selected from the group consisting of hydrogen and lower alkyl; and n is an integer from 1 to 3, with the proviso that when R, is EMI31.3 n cannot be 2.

Inventors: D'AMICO, JOHN JOSEPH
Applicants: MONSANTO COMPANY
Application year: 1979
Main classification: A01N43
IPC codes: A01N43, C07D263, C07D235, C07D277