Amaranthus hybridus

Amaranthus hybridus slim amaranth smooth amaranth... 

Hirschberg, J. and L. McIntosh (1983). Molecular basis of herbicide resistance in Amaranthus hybridus. Science, 222 1346-1349. Hirschberg, J., A.B. Yehuda, I. Packer, and N. Ohad (1987). Mutations resistant to photosystems II herbicides. NATO ASI Series A (Plant Mol. Biol.), 140 357-366. 

De Prado, R., M. Sanchez, J. Jorrin, and C. Dominiguez (1992). Negetive cross-resistance to betazone and pyridate in atrazine-resistant Amaranthus cruentus and Amaranthus hybridus Biotypes. Pestic. Sci., 35 131-136. 

Amaranthus hybridus (also A. chlorostachys) Amaranthus lividus Amaranthus palmeri Amaranthus powellii Amaranthus retroflexus Amaranthus rudis Amaranthus tuberculatuf Ambrosia artemisiifolia Arenaria serpyllifolia Atriplex patulad Bidens tripartita... 

Birschbach, E.D., M.G. Myers, and R.G. Harvey (1993). Triazine-resistant smooth pigweed (Amaranthus hybridus) control in field corn (Zea mays L.). Weed Technol., 1 431-436. 

Foy, C.L. and H.L. Witt (1997). SAN 582, alachlor, and metolachlor control of triazine-resistant (TR) smooth pigweed (Amaranthus hybridus) in no-till com (Zea mays). Weed Technol., 11 623-625. 

Manley, B.S., H.P. Wilson, and T.E. Hines (1998). Characterization of imidazolinone-resistant smooth pigweed (Amaranthus hybridus). 

Schmenk, R.E., M. Barrett, and W.W. Witt (1996). A smooth pigweed (Amaranthus hybridus L.) population resistant to ALS-inhibiting herbicides. Proceedings South Weed Science Society, p. 17. 

Hirschberg, J. and L. Macintosh. 1983. Molecular basis of atrazine resistance in Amaranthus hybridus. Science, 222 1346-1349. 

Amaranthus cruentus L. or A. hybridus L. var. patulus (Bertol.) Amaranthus hybridus L. or A. chlorostachys Willd. Amaranthus lividus L. 

Chenopodium album Senecio vulgaris Amaranthus hybridus Leaf discs buoyancy technique40... 

Resistant biotypes sometimes grow better in the presence of the herbicide than without the herbicide. For instance, Lipecki (pers. comm.) found that a triazine-resistant biotype of Amaranthus hybridus had double the dry weight per plant at 5 kg/ha simazine than without the herbicide. It would be useful to have more such quantitative experiments. This lower resistant biotype productivity when the herbicide is not present results in a stronger lack of competitive fitness in the off years. 

Triazlne-reslstant weeds have appeared In fields where trlazine herbicides have been continuously used. At least 38 resistant weed species have been Identified (2). The weed biotypes are resistant to a number of trlazine herbicides, including atrazlne and terbutryn, and have a characteristic, altered spectrum of sensitivity to other herbicides (1). Resistance in Amaranthus hybridus (J) and Solanum nigrum ( ) has been attributed to a mutation in the chloroplast psbA gene. The frequency of appearance of resistant blotypes has been calculated to be very low C ). It was therefore proposed that a nuclear-encoded chloroplast mutator gene was involved (1). 

Chloroplast Isolation. Chloroplasts of peas, spinach (Spin-acia oleracea L.), and biotypes of Amaranthus hybridus L. suscep-t1b1e or resistant to 2-triazines were isolated and stroma-free thylakoids prepared as previously described (17). Intact chloroplasts were obtained from pea leaves following the method of Blair and Ellis (18). 

We compared the membrane lipid composition of chloroplasts isolated from species of common groundsel (Senecio vulgaris L.), lambsquarters (Chenopodium album L.), and pigweed (Amaranthus hybridus L.) (Table VIII) (W. 

TWO-ELECTRON GATE IN TRIAZINE RESISTANT AND SUSCEPTIBLE AMARANTHUS HYBRIDUS... 

Seed was obtained from a triazine-resistant and a triazine-susceptible population of smooth pigweed ( Amaranthus hybridus ) generously gifted by Drs. D. Ort and R.A. Liebl. The growing condition of the plants and the chloroplast isolation are described in [1]. 

Two-Electron Gate in Triazine Resistant and Susceptible Amaranthus hybridus 547... 

Amaranthus hybridus Smooth amaranth Amaranthaceae Plant Encyclopedia (2012)... 

The appearance of weeds that showed considerable resistance to the triazine herbicides eventually led to detailed biochemical studies that identified resistance mechanisms at the level of a D1 protein amino acid change. Hirschberg and Mclntosh showed that in Amaranthus hybridus this was due to a replacement of serine 264 by glycine. Remarkably, this particular amino acid change did not greatly affect the inhibitory properties of the phenylurea diuron. Subsequent work has shown, however, that changes at amino acids 219 and 275 will give resistance to diuron but have... 

There are a number of factors which can contribute to herbicide selectivity, including soil placement, rates of absorption and subsequent translocation, localization (both within the plant and at the subcellular level), and transformation to products of modified phytotoxicity. In addition, the recent work on the elucidation of the modes of action of the aryloxyphenoxypropionate and cyclohexanedione groups of herbicides has highlighted the importance of species differences in sensitivity of the target site, in this case the enzyme acetyl-CoA carboxylase. The monocot and dicot enzymes studied to date show a remarkable difference in sensitivity to these herbicides which correlates very well with the high level of resistance among dicots. Biotypes of Chenopodium album and Amaranthus hybridus L. resistant to atrazine as a result of a mutation in the 32-kDa protein component of photosystem II would constitute a further example. 

---