Effect Of Various Herbicides Research Articles

Bio-efficacy of various herbicides and their mixtures on weeds and yield of wheat (Triticum aestivum) under subtropical agro-ecosystem

A field experiment was conducted during the winter (rabi) season of 2004-05 and 2005-06 to study the effect of various herbicides and their mixtures on weed growth, yield attribute and yield of wheat (Triticum aestivum L. emend. Fiori & Paol.) under irrigated conditions of subtropical agro-ecosystem of Jammu region. The weed flora observed at site were Anagallis arvensis, Poa annua, Phalaris minor, Trachyspermum and Euphorbia helioscopia, of which the relative density of individual weed species out of total weeds corresponds to 1.1 1 to 4.69 per cent on application of fenoxaprop+metribuzin (120+100 g ailha) at 60 days after sowing (DAS). Among the weed-control treatments, fenoxaprop+metribuzin (120+100 g ailha), though on a par with either tank mix ap- plication of sulfosulfuron + 2,4-D (25+500 g ailha), clodinafop + metsulfuron (60+2 g ailha), isoproturon+2,4-D (750+500 g ailha) or alone application of sulfosulfuron (25 g ailha), metribuzin (175 or 200 g ailha) and isoproturon (1,000 g ailha), reduced the dry weight of weeds significantly than weedy check and other herbicide treatments. It led to significant increase in the yield attributes, viz. effective tillerslm, grainslear and 1,000-grain weight, and the yield of wheat than the rest of the treatments, during both the years of experimentation. Maximum grain yield and yield attributes were recorded in weed-free plots, and reduction of 42.29 and 38.27 per cent in yield was observed in weedy check plots during 2004-05 and 2005-06 respectively.

Herbicides for Reduced Tillage Production in Peanut (Arachis hypogaea) in the Southwest

Field studies were conducted in 1988 and 1989 under dryland and irrigated conditions to determine effects of various herbicides for use in peanuts on weed control and peanut yield under a reduced tillage system. Under dryland and irrigated conditions, sethoxydim + acifluorfen consistently controlled Texas panicum. Paraquat + bentazon controlled Texas panicum poorly under dryland conditions. Pendimethalin + metolachlor provided ≥ 80% Texas panicum control under irrigated conditions.

Conjugation between twoEscherichia colistrains and betweenEscherichia coli(donor) andAzospirillum brasilense(recipient) in the presence of various herbicides

The effects of various herbicides on conjugation (transfer of RP4 plasmid) between two strains of Escherichia coli and between E. coli (donor) and Azospirillum brasilense (recipient) were studied. Prior to the conjugation experiment, the growth of these bacteria in the presence of herbicides was examined. It was observed that except methyl viologen none of these herbicides exert any inhibitory effect on growth. In the presence of methyl viologen the growth of both E. coli strains was completely and the growth of A. brasilense partially inhibited. The conjugation ability of these strains was studied in liquid media and in soil. In liquid media it was observed that except ethiozin all tested herbicides did not affect the conjugation between the E. coli strains. In the presence of ethiozin the formation of transconjugants was partially inhibited. Ethiozin also affected the transfer of the RP4 plasmid between E. coli and A. brasilense. On the other hand, in liquid media atrazine and isoproturon promoted the c...

Behaviour of Herbicides in Dicotyledonous Roots Transformed byAgrobacterium rhizogenes

Mugnier, J. 1988. Behaviour of herbicides in dicotyledonous roots transformed by Agrobacterium rhizogenes. I. Selectivity.—J. exp. Bot. 39: 1045-1056. The effect of various herbicides on the growth of dicotyledonous roots transformed by the root-inducing transferred DNA of Agrobacterium rhizogenes was studied. When a compound affected the growth of different root species differentially, the difference might be attributed to root uptake and metabolism of the herbicide. In general, metabolism of the herbicide led to inactivation (clopyralid, linuron, phenmedipham), but in certain instances, the change resulted in activation (quizalofop-ethyl). Visible effects on the root morphology were observed: dinitroanilines and certain carbamates led to remarkable swelling of the root tips; norflurazon and diflufenican were effective bleaching agents in greening root cultures in Murashige and Skoog medium, whereas the presence of sucrose in the medium antagonized the effect of triazine herbicides. Growth inhibition by sulphonylureas can be antagonized by addition of valine and leucine; asulam inhibition was antagonized by addition of folic acid but glyphosate inhibition was not significantly reversed by aromatic amino acids. Bipyridinium and diphenyl ether herbicides, with certain exceptions, have rapid and devastating phytotoxic effects on root growth. The phytotoxic effects of the herbicides on transformed root growth is discussed with particular reference to their mode of action in intact plants. Key words—Agrobacterium rhizogenes, herbicides, root organ cultures. Correspondence to: Rhone-Poulenc Agrochimie, 69263 Lyon Cedex 09, France.

Stimulation of Glutathione Synthesis in Photorespiring Plants by Catalase Inhibitors

The effect of various herbicides on glutathione levels in barley (Hordeum vulgare L.), tobacco (Nicotiana tabacum L.), soybean (Glycine max [L.] Merr.), and corn (Zea mays L.) was examined. Illumination of excised barley, tobacco, and soybean plants for 8 hours in solution containing 2 millimolar aminotriazole (a catalase inhibitor) resulted in an increase in leaf glutathione from 250 to 400 nanomoles per gram fresh weight to 600 to 1800 nanomoles per gram fresh weight, depending on the species tested. All of this increase could be accounted for as oxidized glutathione. Between 25 and 50% of this oxidized glutathione was reduced when plants were darkened for 16 hours, but there was no significant decline in total glutathione. Another catalase inhibitor, thiosemicarbazide, was as effective as aminotriazole in elevating glutathione in soybean but was less effective in barley and tobacco. Glyphosate, an inhibitor of aromatic amino acid biosynthesis, had no significant effect on glutathione levels in any of the plants examined. Whereas methyl viologen (paraquat), which is a sink for photosystem I electrons, caused oxidation of leaf glutathione in all of the plants but did not increase the total amount of glutathione present.

Effects of Herbicides on in vitro Growth of Mycorrhizae of Pine (Pinus spp.)

Effects of various herbicides on growth of ectotropic mycorrhizal fungi were determined over a 3-week period on modified Melin-Norcrans agar amended with the herbicides at rates of 0, 1, 3, 5, 10, 40, 80, 100, and 500 μg active ingredients/ml. Considerable variation in effect was observed among the herbicides for certain fungi and among the fungi for certain herbicides. All of the test fungi grew in the presence of each of the test herbicides at a rate of 80 μg/ml, and some growth was observed at the 500 μdg/ml rate in a majority of the herbicide-fungus combinations. Significant decreases (P = 0.05) in growth were observed for specific herbicide-fungus combinations at herbicide rates of 1 and 3 μg/ml; however, 50% or greater decreases in fungal colony areas were observed in only 12 of 112 of the combinations at such low rates. The herbicides, in decreasing order of activity against the fungi, were: diphenylethers > dinitroanilines > s-triazines > substituted amides > perfluidone [1,1,1-trifluoro-N-[2-methyl-4-(phenylsulfonyl)phenyl] methanesulfonamide]. With few exceptions, the herbicide concentrations necessary to affect fungal growth significantly were considerably higher than would be expected to occur in soil treated with the test herbicides at recommended application rates.

Effects of Certain Herbicides and Their Combinations on Nitrate and Nitrite Reduction

A study was made concerning the effect of various herbicides, when used alone or in combination, on nitrite accumulation in excised leaves of wheat (Triticum aestivum L., var. ;Centurk'). Treatment of leaves with photosynthetic inhibitor herbicides, known to interfere with the transfer of light energy, caused accumulation of nitrite under illuminated, aerobic conditions. When certain other herbicides, which do not interfere with the photosynthetic process, were applied to leaves and incubated under dark, aerobic conditions, nitrite accumulations were enhanced over those treated with photosynthetic inhibitors or the controls. The combination of photosynthetic inhibitor herbicides and certain other "nonphotosynthetic inhibitor" herbicides caused relatively large amounts of nitrite to accumulate in light or in darkness. Nitrite accumulation occurs when nitrate and nitrite reduction are not in balance. The proposed actions of the herbicides used in this study are discussed. This discussion provides a rationale for the accumulation of nitrite by the herbicide-treated leaves.

The effects of some herbicides and pesticides on sodium uptake by isolated perfused gills from the carp Cyprinus Carpio

1. 1. The isolated perfused gill system was used to examine the effects of various herbicides and pesticides on sodium uptake and branchial vascular resistance. 2. 2. The pesticide, p, p′-DDT, significantly increased sodium uptake and flow rate at the concentration tested. 3. 3. The pesticide, aldrin, and the herbicides, atrazine and trifluralin, significantly decreased sodium uptake, but had no effects on flow rate at the concentrations tested.

The effects of herbicides on the ultrastructure of plant cells.

To single technique has provided an exact means for ascertaining now herbicides modify or inhibit plant growth and development. Electron microscopic studies also have limitations: for example, the amount of tissue that can be examined even in one’s lifetime is exceedingly small. Electron microscopic studies are essentially limited to changes induced by the herbicides in structural components of the cell. The structure of the tissue observed represents only that which is preserved at the time of fixation and an adequate sampling of the normal range of variation in the tissue is difficult. Also, some fixatives (potassium permanganate) destroy organelles such as ribosomes. Although ultrastructural examination may not ultimately provide an exact diagnostic tool, such studies correlated with biochemical investigations provide insight into possible mechanisms of herbicidal action that the latter alone could not provide. Thus, it is the purpose of this review to compare and evaluate the reported effects of various herbicides on plant ultrastructure with particular emphasis on those aspects which differ significantly from normal senescence. Further, an attempt will be made to establish correlations, wherever possible, between herbicidal-induced alterations in ultrastructure with known changes in physiology and growth. The danger that such correlations may be between secondary effects which can mask the primary treatment effects is recognized.

Effect of Various Herbicides on the Respiration of Soil Microorganisms

The effect of Ametryne, Atrazine, Bromacil, Diuron, Fluometuron, Linuron, Prometryne, Terbacil, Trifluralin, and 2,4-D on soil respiration was studied employing the Warburg apparatus. These compounds were used in various concentrations, i.e., 0, 10, 100, and 250 p.p.m. The 10 compounds fell into three categories with regard to their effect on respiration of soil microorganisms: 1. A significant inhibitory effect on oxygen uptake was brought about by adding 2,4-D and Trifluralin to Coto and Fraternidad soils. 2. A weak inhibitory effect on oxygen uptake was noted for low concentrations of Bromacil, Diuron, Trifluralin, and 2,4-D, and for high concentrations of Ametryne, Bromacil, Linuron, and Diuron in soils. 3. A weak to moderate stimulatory effect on oxygen uptake was recorded with low concentrations of Ametryne, Diuron, Fluometuron, 2,4-D and for high concentrations of Atrazine, Linuron, and Terbacil in soils.

Influence of herbicides on photosynthetic activity and transpiration rate of intact plants

AbstractThe effect of various herbicides on photosynthesis, respiration and transpiration of intact plants has been studied in a routine assembly. Simultaneous measurements were made under different experimental conditions in four small plant chambers, in which the shoots of various plant species can be accommodated.The herbicide is applied during measurement, so that the effect can be related to the photosynthetic activity of the same plants before treatment.The selectivity of various herbicides was studied by determining the capacity of a plant species to inactivate a herbicide absorbed by the roots. These and other differential effects of various herbicides on photosynthetic activity of different plant species coincide with the selective properties in the field. Such differences are also observed after leaf sprayings. The duration of the experiments is kept short.Bean plants were studied under various experimental conditions of air humidity, light intensity and temperature resulting in different transpiration rates. The decrease in photosynthetic activity owing to the presence of a herbicide in the nutrient solution at a standard concentration was more rapid at the higher transpiration rates. The total transpiration during treatment up to 50% inhibition of photosynthesis was constant under the various experimental conditions.Specific inhibitors of the photosynthetic process had a more pronounced effect on the photosynthetic activity than on transpiration rate. Some other herbicides affect transpiration as well as photosynthesis.

Red Pine Needle Structure

READERS of the recent article by Kozlowski and Clausen1 on the anatomical responses of the needles of red pine (Pinus resinosa Ait.) to herbicides may have been confused by the extreme variations in needle structure which these authors described and illustrated. Kozlowski and Clausen attributed many of the anatomical differences between “needles” shown in their Fig. 1 to the effects of various herbicides applied to the soil in which the seedlings were grown. From what is known of the leaf structure of pine seedlings2, however, we concluded that they had illustrated and described three different kinds of foliar appendages of red pine. Their Fig. 1A, a transection of a “needle” from a non-treated seedling, seems to be a primary leaf, as is Fig. 1D from a treated plant. Their Figs. 1B, C and E are cotyledons, and F resembles a shrivelled secondary leaf.

A survey of herbicides for their effect upon protein synthesis.

The means by which many herbicides kill susceptible plants are presently unknown (1, 3). Although it is not essential to know the mode of action in order to develop and use a herbicide efficiently, the screening processes by which herbicides are discovered are based upon comparative biochemistry. Selective herbicides with low mammalian toxicity (2) must take advantage of differences in metabolism between plants and animals, and between plant species, just as therapeutically effective antibiotics take advantage of differences between bacterial and mammalian biochemistry. Knowledge of herbicide effects may prove useful for other areas within plant physiology. A screening technique has been used in the present study to determine the effect of various herbicides on the incorporation of leucine into protein. The restilts show differences between those herbicides which, more or less directly, inhibit protein synthesis, and those which act upon quite unrelated pathways. This approach is designed to indicate the areas that should be studied more intensively for each herbicide.

Effect of Various Herbicides on Glucose Metabolism in Root Tissue of Garden Peas. II. Plant Growth Regulators and Other Herbicides

Effect of Various Herbicides on Glucose Metabolism in Root Tissue of Garden Peas. II. Plant Growth Regulators and Other Herbicides

Herbicide Control of Coppicing in Teak

1. The effectiveness of various herbicides on repressing growth of coppice shoots of teak (Tectona grandis L.) stumps was studied, since such control is important following thinning operations in teak plantations in Trinidad. 2. The sodium salt of 2,4-dichlorophenoxyacetic acid (2,4-D) in water, the butyl ester of 2,4-D in water, the sodium salt of trichloroacetic acid (TCA), and sodium tetraborate were only partially effective. The butyl ester of 2,4-D in a dieseline oil carrier, the butyl ester of trichlorophenoxyacetic acid (2,4,5-T) in both a water carrier and a dieseline oil carrier, and the triethanolamine salt of 2,4-D were completely effective in repressing growth of coppice shoots. 3. It is suggested that, in order to control coppicing of teak stumps, either a 2% solution of 2,4,5-T in an oil carrier or a concentrated solution of the triethanolamine salt of 2,4-D should be sprayed on the cut surface and sides of teak stumps by knapsack sprayer during the first week after the trees have been cut.