CA1127858A - Reduction in the transpiration of crop plants - Google Patents

Abstract

O.Z. 33,049 ABSTRACT OF THE DISCLOSURE: Process for reducing transpiration in monocotyledonous crop plants, especially Indian corn, by treating the plants with prior art pyridazone derivatives, especially 1-phenyl-4-dimethylamino-5-chloropyridazone-(6).

Description

O.Z. 33,049 REDUCTION IN THE TRANSPIRATION OF CROP PLANTS
The present invention relates to the use of prior art pyridazone derivatives, especially l~phenyl-4-dimethylamino-5-chloropyridazone-(6)~ for reducing transpiration in mono-1~ cotyledonous crop plants, especially Indian corn.
Influencing water regulation in crop plants, especially under arid growth conditions, is of considerablQ economic importance. The aim of many prior art agricultural measures under the said conditions is to economize on the ~ater con-sumption of the crop plants.
In addition to Xno~n agricultural techniques, ~.g., the dry farming system, attempts have also been made to save water by in~luencing the transpiration OI' crop plants. Transpiration can be reduced particularly in broadleaved plants, e.g., vines, by spraying them with film-forming substances (polymers, paraf-fin) (U,S. 3,676,102 and U.S. 3,339,373). However, as in this process the ~unction of the stomata, which are essential for gas exchange, îs inhibited, the formation of greQn material by the crop plants often drops because their growth is hindered.
Apart from this, narrow-leaf plants are not so suitable for such a treatment because the surface area o~ the leaves is less than that of broadleaved ~lants and because only a small amount of ~Z7~5~

- 2 - O.Z. 33,049 film-forming material adheres to the narrow leaves.
~ e have now found that prior art pyrldazone derivatives of the formula CH}~ CH3 ,~
N~
R

where R denotes unsubstituted phenyl, phenyl mono- or polysub-stituted by halogen or al~Jl of 1 to 3 carbon atoms, unsubstltuted cyclohexyl9 or cyclohexyl mono- or polysubstituted by halogen or alkyl of 1 to 3 carbon atoms and R denotes chlorine or bromine, are suitable for reducing transpiration in Indian corn and panic grass.
Halogen is preferably chlorine or bromine, and alkyl of 1 to 3 carbon atoms is preferably methyl, ethyl, propyl or isopropyl.
These compounds have been disclosed as herbicides for the selective control o~ weeds in beets or cotton (German 1,105,232 and 1,123,510). The compound 1-phenyl-4-dimethylamino-5-chloro-pyridazone-(6) is particularly important.
By 'reduction in transpiration', we mean a reduction in the evaporation of water through the surface of crop plants.
When the active ingredients are applied at appropriate rates, no negative effects on growth and yield occur. The active ingredients exert t.heir action not only ~Ihen applied to the soil (root take-up - ~ree~ergQnce treatment~ but also when 3o ~ :1 278~

- 3 - o.z. 33,oL~g applied to the leaves (postemergence treatment); seed treatment may also have the desired effect. ~.lhereas preemergence treat-ment is particularly advisable in areas with a permanent lack of water, postemergence treatment is suitable especially where, in the event of temporary periods o~ drought, it is preferred to apply the active ingredients only if and when required.
Examples of active ingredients are 1-phenyl-4-dimethyl-amino 5-chloropyridazone-t6), 1-phenyl-4-dimethylamino-5-bromo-pyridazone-(6), 1-cyclohexyl-4-dimethylamino-5-chloropyrida-zone-(6), 1-p-chlorophenyl-4-dimethylamino-5-chloropyridazone-(6), and 1-p-methylphenyl-4-dimethylamino-5-chloropyridazone-(6).
The active ingredients may be applied for instance in the form of directly sprayable solutions, powders, suspen~
sions (including high-percentage aqueous, oily or other suspensions), dispersions, emulsions, oil dispersions, pastes, dusts, broadcasting agents, or granules by spraying, atomizing~
dusting, broadcasting or watering. The forms of application depend entirely on the purpose for which the agents are being used; in any case they should ensure a ~ine distribution of the active ingredients.
For the preparation of solutions~ emulsions, pastes and oil dispersions to be sprayed direct, mlneral oil fractions of medium to high boiling point, such as kerosene or diesel oil, further coal-tar oils, and oils of vegetable or ani~al origin, aliphatic, cyclic and aromatic hydrocarbons such as benzene, toluene, xylene, oaraffin, tetrahydronaphthalene, alkylated

4 - 0.~. 33,049 naphthalenes and their derivatives such as methanol, ethanol, propanol, butanol, chloroform, carbon tetrachloride, cyclo-hexanol, cyclohexanone, chlorobenzene~ isophorone, etc. and strongly polar solvents such as dimethylformamide, dimethyl-sulfoxide, ~-methylpyrrolidone, water, etc. are suitable.
~ queous formulations may be prepared from emulsion con-centrates, pastes, oil dispersions or wettable powders by adding water. To prepare emulsions, pastes and oil dispersions the ingredients as such or dissolved in an oil or solvent may be homogenized in water by means of wetting or dispersing agents, adherents or emulsifiers. Concentrates which are suit-able for dilution with T,~rater may be prepared from active in-gredient, wetting agent, adherent, emulsifying or dispersing agent and possibly solvent or oil.
Examples of surfactants are: alkali metal, alkaline earth ;
metal and ammonium salts of ligninsu:Lfonic acid, naphthalene-sulfonic acids, phenolsulfonic acids, alkylaryl su].fonates, alkyl sulfates, and alkyl sulfonates, alkali metal and alkaline earth metal salts of dibutylnaphthalenesulfonic acid, lauryl ether sul~ate, ~atty alcohol sul~ates~ al!~ali metal and alkaline earth metal salts of fatty acids, salts of sulfated hexadecanols, heptadecanols, and octadecanols, salts of sul-fated fatty alcohol glycoL ethers, condensation products of sulfonated naphthalene and naphthalene derivatives ~lith formaldehyde, condensation products of naphthalene or naphthalene-sulfonic acids with phenol and formaldehyde, polyoxyethylene

- 5 -octylphenol ethers, ethoxylated isooctylphenol, etho~Jlated octylphenol and ethoxylated nonylphenol, alkylphenol poly-glycol ethers, tributylphenol polyglycol ethers, alkylaryl pol~Jester alcohols, isotridecyl alcohols, fatty alcohol ethylene oxide condensates, ethoxylated castor oil, poly-oxyethylene alk~Jl ethers, ethox~Jlated polyoxypropylene, lauryl alcohol polyglycol ether acetal, sorbitol esters3 lignin, sulfite waste liquors and methyl cellulose.
Powders, dusts and broadcasting agents may be prepared by mixing or grinding the active ingredients with a solid carrier.
Granules, e.g., coated, impregnated or homogeneous gra-nules, may be ~repared by bonding the active ingrsdients to solid carriers. Examples of solid carriers are mineral earths such as silicic acid, silica ~els, silicates, talc, kaolin3 Attaclay,*limestone, lime, chalk, bole, loess, clay, dolomite, diatomaceous earth, calcium sulfate, magnesium sulfate, magnesium oxide, ground plastics, fertilizers such as ammonium sulfate, ammonium phosphate, ammonium nitrate, and ureas, and vegetable products such as grain ~lours, bar~ meal, wood meal, and nutshell meal, cellulosic powders, etc.
The formulations contain from 0.1 to 95, and preferably 0.5 to 90, % by weight of active ingredient. Application rates are ~rom 0 1 to 10 kg of active ingredient per hectare.
The following examples illustrate the action of the active ingredients. The active ingredient used was 1-phenyl-4-dimethyl-amino-5-chloropyridazone-(6) (hereinafter designated A).

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- 6 - O.Z. 33,049 EXAr~PLE 1 The roots of 7 young Indian corn plants were dipped through a gastight glass plate into a nutrient solution. The active ingredient was introduced into the nutrient solution when the plants had reached a height of ~6 cm. The concen-trations of the active ingredient in the nutrient solution were 1~ 2 and 4 mg/l, equivalent to an application rate in the open of 1.5, 3 and 6 kg/ha. The plants were then placed in gastight cylindrical glass vessels and connected to the water vapor measuring unit. The results were recorded by multiple recorders and calculated as grams of water per vessel. For 8 days after the active ingredient had been introduced into the nutrient solution, the transpiration of the plants was measured day and night during the periods of light and darkness at 20 to 23C. The influence on transpiration is given in Tables 1 and 2.

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_ g _ O.Z. 33,049 In a ~urther experiment (also carried out at room tem-perature), Indian corn plants were grown in the same manner as in Example 1. The active ingredient was added to the nutrient solution when the plants were 23 cm high, in amounts of 1.3 and 4.0 mg/l (equivalent to 2 and 6 kg/ha). The comparative agent in this experiment was abscisic acid (ABA), the action of which on the stomata and thus on plant transpiration has been disclosed (K. Raschke, Ann. Rev. Plant Physiol., Palo Alto, Cal,, 26, 309-340, 1975). The results given in Tables 3 and 4 show that, under the conditions maintained, the desired effect was only achieved with active ingredient A.
Table 3 ~ranspiration in Indian corn during the period of light in g of H20/vessel; comparative experiment with A~A

Active Appln. rate 2nd day 4th day lst-5th day ingredient in kg/ha total absolute relative .
Control (nutrient solution untreate`d) 141.1 161.3 767.8100%

ABA 2 141.1 165.8 785.1102.3%

A 2 109.8 129.9 626.681.6 A 6 101.9 116.5 535.469 7%

3o 7~5~
- 10 - O.Z. 33,o4a Table 4 Transpiration in Indian corn durlng the ?eriod of darkness in g of H20/vessel; comparative experiment with ABA
Active Appln. rate 2nd night 4th night lst-5th night ingredient in kg/ha total absolute relative _ _ _ Control (untreated) 28.036.0 157.6 100%
ABA 2 28.0 40.0162.0 102.8%
A 2 19.6 16.098.8 62.7%
A 6 16.8 12.074.8 47.5%

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In the greenhouse, Indian corn plants were grown in pots in a mineral soil. After the seedlings had emerged and before the first lea~ had deve~oped, the pots were covered with a water vapor-proof sheeting in such a manner that each plant was able to grow through an opening in the sheeting. The active ingredient was applied upon sowing; :i.e., preemergence~ at rates o~ 1.5, 3 and 6 mgtvessel, equivalent to 1.5, 3 and 6 kg/ha.
The water supply was adjusted to 60% of the maximum water capa- -city. When the plants had reached a height of 15 cm, their water consumption was measured in the greenhouse at 20C and a relative humidity of 40%, and in an atmospheric laboratory at 35C and a relative humidity of 30%. It was found that the treated plants consumed less water than the untreated plants. The results are given in Tables 5 and 6.

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- 11 ~ 0~z~ 33~049 Table 5 In~luence on ~rater regulation in Indian corn under greenhouse conditions ( 20C ~ 40~ relative humidity) Active Appln. rate Water consumDtion ingredient in 24 hours in 36 hours g rel. g rel.
~r _ _ _ _ ..... . _ _ _ _ _ . _ _ . _ _.__ __ .. _ __ Control (untreated) 32~ 5 100% 41~ 7 10070 A 1,5 kg/ha 29~2 ~9~8% 38~3 91~8%
A 3 kg/ha 19~2 59~1% 27~7 66~4%
A 6 kg/ha 10. 4 32.0% 14 ~ 8 35. 5~
1 0 _ _ .. __ ... .. _ _ .

Table 6 Influence on water regulation in Indian corn under severe con-ditions in atmospheric laboratory (35 C and 30~ relative humidlty) Active Appln. rate l,~ater consumption ingredient - in 4 hours g rel.
. . _ _ Control (untreated) 34.C~ 100%
A 105 kg/ha 24.0 68.8%
A 3 k~/ha 20.0 57 ~ 3%
A 6 kg/ha 12.1 34. 7%

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Claims (2)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A process for reducing transpiration in Indian corn and panic grass, wherein the plants or the soil are treated with a pyridazone derivative of the formula , where R denotes unsubstituted phenyl, phenyl mono- or poly-substituted by halogen or alkyl of 1 to 3 carbon atoms, un-substituted cyclohexyl, or cyclohexyl mono- or polysubstituted by halogen or alkyl of 1 to 3 carbon atoms and R1 denotes chlorine or bromine.

2. A process as claimed in claim 1, wherein the plants or the soil are treated with 1-phenyl-4-dimethyl-amino-5-chloropyridazone-(6).