Sensitivity to herbicides

Each one-point mutant was prepared from the two-point mutant by PCR and the self-polymerase reaction. Recombinant ALS s from these ALS genes were expressed in Eschericia coli as GST-flised proteins (Fig. 11) and the proteins were examined for their sensitivities to herbicides. 

Selection of maize tissue cultures for resistance to lethal herbicide concentrations resulted in at least six independent mutations for resistance to one or both herbicide families [2,3]. These mutants are inherited as single partially dominant genes and most mutations behave as alleles of the same genetic locus. ACCase I activity in mutant leaves and embryos was significantly less sensitive to herbicide inhibition indicating that the plastid-localized form had been altered [4]. ... 

Herbicides also inhibit 5- (9/-pymvylshikiniate synthase, a susceptible en2yme in the pathway to the aromatic amino acids, phenylalanine, tyrosine and tryptophan, and to the phenylpropanes. Acetolactate synthase, or acetohydroxy acid synthase, a key en2yme in the synthesis of the branched-chain amino acids isoleucine and valine, is also sensitive to some herbicides. Glyphosate (26), the sulfonylureas (136), and the imida2oles (137) all inhibit specific en2ymes in amino acid synthesis pathways. 

The structure-selective, electron-capture detector (ECD) is the second aost widely used ionization detector [115-118]. It owes Buch of its popularity to its unsurpassed sensitivity to a wide range of toxic and biologically active coapounds. Consequently, it is widely used in trace analysis for the detemination of pesticides, herbicides and industrial chemicals in the... 

The hydrilla 2-node explants were also sensitive to the herbicides chlorsulfuron. One part per billion chlorsulfuron (ca. 3 X 10 M reduced growth of new shoots by almost 80% but had no effect on new shoot initiation (Table XI). when the herbicide was removed after 14 days, new shoots began to elongate. 

Thus it is significant that for such si/m-triazine herbicides as simazine, atrazine, etc., the health and hygiene MPC (toxicity to warm-blooded animals, including humans) and phytotoxic MPC (toxicity to plants) differ by more than an order of magnitude 0.2-0.5 mg/kg for warm-blooded animals, and 0.01 mg/ kg for plants [89]. Warm-blooded animals and arthropods have a difference in sensitivity to many pyretroids that can reach tens of thousands of times [90]. 

Furthermore, the use of Ralstonia eutropha JMP134-containing sensors for the determination of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) has been described [118,121]. This sensor was sensitive to 2,4-D and 2,4,5-T (2,4,5-trichlorophenoxyacetic acid) with a detection Emit of 40 mg 1 with a response time of 15 s. Moreover, catechol, benzoic acid, and sahcylaldehyde caused higher signals, but no or very little signal was obtained for phenol, biphenyl, and the usual substrates such as glucose, fructose, ethanol, and acetate. 

Paul, E., Johnson, S. and Skinner, K.M. (2006) Fish and invertebrate sensitivity to the aquatic herbicide AquaKleen . J Freshw Ecol, 21, 163—168. 

Phenoxyalkanoic acid herbicides are not amenable to direct gas chromatographic determination because of the high polarity or low volatility of the compounds and must be converted to their more volatile derivatives. The sensitivity of the electron capture detector towards alkyl esters of 4-chloro-2-methylphenoxy acetic acid, 4-chloro-2-methylphenoxy butyric acid, etc., is very poor. The methyl ester of 4-chloro-2-methylphenoxy acetic acid was 100 times less sensitive to electron affinity detection than the 2,4-D-methyl ester [396]. 

In contrast, Ernst et al, (1996) have shown that a substitution at Ser264 does not necessarily lead to herbicide resistance. They found both Ser and Gly at position 264 in various sensitive and resistant biotypes of common groundsel. However, all resistant biotypes of black nightshade had Gly at position 264, but some of the sensitive biotypes also had Gly at this position. They suggested that the effect of this mutation in sensitive biotypes was overcome by two additional mutations in these biotypes alanine at position 251 (Ala25i) to arginine (Arg) and valine at position 280 (Val280) to leucine (Leu). In sensitive common lambsquarters, only Ser was present at position 264 either Ser or Gly were detected at position 264 in different atrazine-resistant plants (Ernst et al, 1996). 

For example, kochia is normally very sensitive to atrazine and can often be controlled with l.lkg/ha (llb/A) along railroads and on farm lands. However, Burnside et al. (1979) reported that after 13 years of atrazine use, Union Pacific personnel were applying up to 15 kg/ha (13 lb/A) with poor control. These high rates are no longer allowed for atrazine uses. The use of mixtures of triazines and herbicides with alternate modes of action has been an effective management strategy to control weeds resistant to triazines. 

Target site cross-resistance, in which a change at the site of action of one herbicide also confers resistance to herbicides from a different class (e.g., selection by triazine-resistant D1 protein that is also less sensitive to triazinones). 

The term negative cross-resistance is used when a herbicide-resistant biotype is more sensitive to and more easily controlled by classes of herbicides other than the class to which it is resistant. 

Aquatic animals were less sensitive to the triazines than were aquatic plants. Toxicity to fish and arthropods varied, with fish or crustaceans sharing the position of most sensitive aquatic animal, depending on the herbicide. In the case of atrazine, arthropods were generally more sensitive than fish. Ratios of the 10th centiles between animals and plants were varied. The animal/plant ratio for atrazine (arthropods) was 24, while hexazinone was 202800. The hexazinone data were from a small data set, and the atrazine data were for arthropods and could not be compared to data for the other triazines. However, the ratios for the other triazines also varied over an order of magnitude, from 176 for prometon to 1688 for prometryn. Since the molecular weights of the triazines are similar, one would expect their... 

In later phases of my illness I became sensitive to more substances first paint, then amalgam, pesticides, herbicides and car exhaust. The last sensitivities to join the list were perfumes and other scent substances. You can try to avoid many things, but unfortunately these scents substances are found almost everywhere and there is barely any sympathy for this kind of problem. 

I use soil solarization for crops like carrots that are the most sensitive to weed competition, and the most labor intensive to weed. Since experiential learning is the teaching style of the class, (the students learn concepts by putting their bodies to work), to answer Katie s question I ask the class to follow me back into the heat so we can get to work using this method of controlling weeds without herbicides. 

Uses Picloram belongs to the pyridine family of compounds. It is a systemic herbicide used for the control of woody plants and a range of broadleaf weeds. Most grasses are resistant to picloram. It is classified by the USEPA as RUP because of its mobility in water, combined with extreme sensitivity to many important crop plants.2,12,13,37... 

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