Competitive Adsorption of Phenoxy Herbicide Chemicals in Soil

1992 ◽  
Vol 26 (9-11) ◽  
pp. 2121-2124 ◽  
Author(s):  
S. Susarla ◽  
G. V. Bhaskar ◽  
S. M. Rao Bhamidimarri
Keyword(s):  
Competitive Adsorption ◽  
Pure Component ◽  
The Other ◽  
Dichlorophenoxyacetic Acid ◽  
Volcanic Soil ◽  
Adsorption Capacities ◽  
Phenoxy Herbicide ◽  
Chlorophenoxyacetic Acid ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
Component Adsorption

A modified Freundlich-type bicomponent adsorption isotherm proposed by Sheindorf et al. (1981) was used to describe the competitive adsorption of 2,4-dichlorophenoxyacetic acid (2,4-D) and 2-methyl-4-chlorophenoxyacetic acid (MCPA) onto volcanic soil. The adsorption capacities of 2,4-D and MCPA reduced in presence of the other component compared to pure component adsorption capacities.

scholarly journals Competitive Adsorption and Desorption of 2,4-D and PCOC in a Volcanic Soil

1991 ◽  
Vol 8 (4) ◽  
pp. 184-195
Author(s):  
Sridhar Susarla ◽  
G.V. Bhaskar ◽  
S.M. Rao Bhamidimarri
Keyword(s):  
Competitive Adsorption ◽  
Single Component ◽  
Volcanic Soil ◽  
Adsorption And Desorption ◽  
Initial Concentration ◽  
Adsorption Capacities ◽  
Phenoxy Herbicide

The competitive adsorption and desorption of 2,4-D and PCOC, two of the commonly used phenoxy herbicide chemicals, in a volcanic soil has been examined. A Freundlich-type isotherm incorporating competition between the solutes was used to analyze the adsorption and desorption data. The competition coefficients for 2,4-D and PCOC were linearly dependent on the initial concentration for adsorption and on the amount adsorbed for desorption. The adsorption capacities of 2,4-D and PCOC in a bicomponent system were reduced by 10% and 8%, respectively, in comparison to their single-component values. The desorption studies showed that both 2,4-D and PCOC were difficult to desorb in a bicomponent system.

The role of a metabolic intermediate in the biodegradation of inhibitory substrates

1997 ◽  
Vol 36 (10) ◽  
pp. 27-36 ◽  
Author(s):  
P. Mungkarndee ◽  
S. M. Rao Bhamidimarri ◽  
A. J. Mawson ◽  
R. Chong
Keyword(s):  
The Other ◽  
Metabolic Product ◽  
Dichlorophenoxyacetic Acid ◽  
Mutual Inhibition ◽  
Metabolic Intermediate ◽  
Batch Cultures ◽  
Ortho Cresol ◽  
2,4 Dichlorophenoxyacetic Acid

Biodegradation of the mixed inhibitory substrates, 2,4-dichlorophenoxyacetic acid (2,4-D) and para-chloro-ortho-cresol (PCOC) was studied in aerobic batch cultures. Each substrate added beyond certain concentrations inhibited the degradation of the other. This mutual inhibition was found to be enhanced by 2,4-dichlorophenol (2,4-DCP) which is an intermediate metabolic product of 2,4-D. When 2,4-DCP accumulated to approximatelY 40 mg/l degradation of all compounds in the mixed 2,4-D and PCOC substrate system was completely inhibited. The degradation of 2,4-D and PCOC individually was also found to be inhibited by elevated concentrations of 2,4-DCP added externally, while PCOC inhibited the utilization of the intermediate.

Two Enzyme Immunoassays to Screen for 2,4-Dichlorophenoxyacetic Acid in Water

1987 ◽  
Vol 70 (5) ◽  
pp. 874-878 ◽  
Author(s):  
James Fleeker
Keyword(s):  
Limit Of Detection ◽  
Solid Phase ◽  
Dichlorophenoxyacetic Acid ◽  
Carrier Protein ◽  
Similar Response ◽  
Enzyme Immunoassays ◽  
Concentration Step ◽  
Chlorophenoxyacetic Acid ◽  
Phenoxy Herbicides ◽  
2,4 Dichlorophenoxyacetic Acid

Abstract Two solid-phase enzyme immunoassays were developed to measure 2,4-dichlorophenoxyacetic acid (2,4-D), using 2 sets of structurally distinct immunogens and enzyme ligands. The 2,4-D analog, 2-methyl- 4-chlorophenoxyacetic acid (MCPA), gave a similar response with both methods, whereas other phenoxy herbicides cross-reacted differently. In method A, the aromatic moiety of 2,4-D was distal from the carrier protein and labeled enzyme, whereas in method B, the acetic acid portion of the herbicide was distal. The use of both methods to screen for this herbicide in ground water and municipal and river water reduced the number of false-positive responses. Water sources having a low background response could be monitored with either method alone. When a concentration step, with disposable C18 extraction columns, was used, the limit of sensitivity was 5 ng/L,. Method A was the more sensitive of the 2 methods with a limit of detection of 10 j*g/L without the concentration step

EXPERIMENTS ON THE RELATIVE SUSCEPTIBILITY OF WEEDS TO AUXIN HERBICIDES

1962 ◽  
Vol 40 (11) ◽  
pp. 1401-1409 ◽  
Author(s):  
J. R. Hay
Keyword(s):  
Phaseolus Vulgaris ◽  
Root Formation ◽  
Effective Control ◽  
Inorganic Salts ◽  
Dichlorophenoxyacetic Acid ◽  
Functional Importance ◽  
Molecular Configuration ◽  
Auxin Herbicides ◽  
Chlorophenoxyacetic Acid ◽  
2,4 Dichlorophenoxyacetic Acid

Sections of stems of Silene cucubalus, Galeopsis tetrahit, and Phaseolus vulgaris were cultured under sterile conditions in media containing inorganic salts, sucrose, agar, and the herbicides 2-methyl, 4-chlorophenoxyacetic acid, 2,4-dichlorophenoxyacetic acid, or 2-(2,4,5-trichlorophenoxy)propionic acid. The herbicide which gave the most effective control of a species under field conditions was also the most active in inducing root formation and proliferation on stem sections of that species. The response of the sections to these auxin herbicides diminished as the plants from which the sections were taken became more mature. The amount of herbicide recovered from treated shoots of these species was not correlated with susceptibility. It is postulated that susceptibility to these materials depends upon (i) the affinity of the species for the molecular configuration of the herbicide and (ii) the relative amount and functional importance of the susceptible tissues at the time of treatment.

scholarly journals Characterization of Hapten-Protein Conjugates: Antibody Generation and Immunoassay Development for Chlorophenoxyacetic Acid Pesticides

2009 ◽  
Vol 92 (6) ◽  
pp. 1773-1779 ◽  
Author(s):  
Robin C Boro ◽  
K Vikas Singh ◽  
C Raman Suri
Keyword(s):  
Inhibitory Concentration ◽  
Dichlorophenoxyacetic Acid ◽  
Protein Conjugation ◽  
Protein Conjugates ◽  
Highly Sensitive ◽  
Ic50 Values ◽  
Chlorophenoxyacetic Acid ◽  
2,4 Dichlorophenoxyacetic Acid

Abstract The generation of specific and sensitive antibodies against small molecules is greatly dependent upon the characteristics of the hapten-protein conjugates. In this study, we report a new fluorescence-based method for the characterization of hapten-protein conjugates. The method is based on an effect promoted by hapten-protein conjugation density upon the fluorescence intensity of the intrinsic tryptophan chromophore molecules of the protein. The proposed methodology is applied to quantify the hapten-protein conjugation density for two different chlorophenoxyacetic acid pesticides, 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4-dichlorophenoxybutyric acid (2,4-DB), coupled to carrier protein. Highly sensitive anti-2,4-D and anti-2,4-DB antibodies were obtained using these well-characterized hapten-protein conjugates. The generated antibodies were used in an immunoassay format demonstrating inhibitory concentration (IC50) values equal to 30 and 7 ng/mL for 2,4-D and 2,4-DB, respectively. Linearity was observed in the concentration range between 0.1500 ng/mL with LODs around 4 and 3 ng/mL for 2,4-D and 2,4-DB, respectively, in standard water samples. The proposed method was successfully applied for the determination of the extent of hapten-protein conjugation to produce specific antibodies for immunoassay development against pesticides.

scholarly journals 116 Somatic Embryogenesis and Organogenesis in Cowpeas

HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 461D-461 ◽  
Author(s):  
Lurline Marsh
Keyword(s):  
Somatic Embryogenesis ◽  
Indoleacetic Acid ◽  
Casein Hydrolysate ◽  
The Other ◽  
Dichlorophenoxyacetic Acid ◽  
Embryonic Axes ◽  
Embryo Formation ◽  
Stage Embryo ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
Cotyledonary Stage

Four cowpea [Vigna unguiculata (L). Walp] genotypes; IT 82E-18, IT 82E-16, Pinkeye Purple Hull, and Coronet were tested for somatic embryo formation and embryogenesis. Explants were 3-week-old cotyledons from which the embryonic axes were removed. Cotyledons were cultured in eight media combinations representing modifications of two media, one containing Murashige and Skoog Basal salt with B5 vitamins (MSB), 500 mg/L casein-hydrolysate (CS), 500 mg/L sodium chloride, 3% sucrose, 0.7% agar, 2mg/L 2,4-dichlorophenoxyacetic acid (2,4-D) and 0.5 mg/L benzylamino purine, and the other containing (MSB), 3% sucrose, 40 mg/L 2-4-D and 0.2% gellan gum. After 1 month, 40% to 100% of explants produced calli and few produced shoots. Subcultured shoots in MS with 0.1 mg/L indole-3-butyric acid (IBA) or with IBA and 0.5mg/L kinetin (KT) failed to produced roots. The only green cotyledonary stage embryo was produced on this latter medium. Subculture of calli in MSB containing CS, mannitol, sucrose, agar, indoleacetic acid, and KT produced cream-colored globular embryos, roots, and a few leaves.

Control of Acacia flavescens with herbicides

1972 ◽  
Vol 12 (57) ◽  
pp. 441 ◽  
Author(s):  
DR Bailey
Keyword(s):  
Dibutyl Phthalate ◽  
The Other ◽  
Dichlorophenoxyacetic Acid ◽  
Panicum Maximum ◽  
Other Hand ◽  
Discernible Effect ◽  
Guinea Grass ◽  
Survival And Growth ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
Pasture Legume

Acacia flavescens seedlings and suckers were effectively controlled with 2,4,5-trichlorophenoxyacetic acid (2,4,5-T). When water was used as the herbicide carrier, seedling control improved with 2,4,5-T rates up to 2.24 kg of acid equivalent (a.e.) ha-1. However, the control of root shoots (suckers) did not improve with dosages above 1.12 kg a.e. ha-1. Diesel distillate was superior to water when used as a 2,4,5-T carrier for seedling control, but there was no difference between the two for sucker control. 2,4-dichlorophenoxyacetic acid (2,4-D) was not effective on A. flavescens seedlings. At equivalent rates 4-amino-3,5,6-trichloropicolinic acid (picloram) was as effective on A. flavescens seedlings as 2,4,5-T. Picloram was more damaging to the pasture legume Stylosanthes guyanensis ssp. gayanensis than was 2,4,5-T. Bioassay did not detect picloram in the top 96 cm of soil 15 months after applying 1.12 kg a.e. ha-1 of picloram. It is possible that loss through leaching was substantial because the soil was sandy and approximately 375 cm of rain had fallen. Addition of dibutyl phthalate (DP) at 5 per cent V/V to a diesel distillate-2,4,5-T mixture had no discernible effect on the control of A. flavescens seedlings. However, DP at 20 per cent V/V impaired 2,4,5-T activity. Acacia seedling numbers were reduced in a newly sown pasture through the application of superphosphate containing 9.6 per cent P at 570 kg ha-1. On the other hand, the survival and growth of Panicum maximum (guinea grass) was appreciably improved, which suggested that increased competition from guinea grass was responsible for Acacia suppression.

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