ON THE MECHANISM OF RESISTANCE TO PARAQUAT IN HORDEUM-GLAUCUM AND H LEPORINUM - DELAYED INHIBITION OF PHOTOSYNTHETIC O-2 EVOLUTION AFTER PARAQUAT APPLICATION

C Preston, JAM Holtum, Stephen Powles

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    Abstract

    The mechanism of resistance to paraquat was investigated in biotypes of Hordeum glaucum Steud. and H. leporinum Link. with high levels of resistance. Inhibition of photosynthetic O2 evolution after herbicide application was used to monitor the presence of paraquat at the active site. Inhibition of photosynthetic O2 evolution after paraquat application was delayed in both resistant biotypes compared with the susceptible biotypes; however, this differential was more pronounced in the case of H. glaucum than in H. leporinum. Similar results could be obtained with the related herbicide diquat. Examination of the concentration dependence of paraquat-induced inhibition of O2 evolution showed that the resistant H. glaucum biotype was less affected by herbicide compared with the susceptible biotype 3 h after treatment at most rates. The resistant H. leporinum biotype, in contrast, was as inhibited as the susceptible biotype except at the higher rates. In all cases photosynthetic O2 evolution was dramatically inhibited 24 h after treatment. Measurement of the amount of paraquat transported to the young tissue of these plants 24 h after treatment showed 57% and 53% reductions in the amount of herbicide transported in the case of the resistant H. glaucum and H. leporinum biotypes, respectively, compared with the susceptible biotypes. This was associated with 62% and 66% decreases in photosynthetic O2 evolution of young leaves in the susceptible H. glaucum and H. leporinum biotypes, respectively, a 39% decrease in activity for the resistant H. leporinum biotype, but no change in the resistant H. glaucum biotype. Photosynthetic O2 evolution of leaf slices from resistant H. glaucum was not as inhibited by paraquat compared with the susceptible biotype; however, those of resistant and susceptible biotypes of H. leporinum were equally inhibited by paraquat. Paraquat resistance in these two biotypes appears to be a consequence of reduced movement of the herbicide in the resistant plants; however, the mechanism involved is not the same in H. glaucum as in H. leporinum.
    Original languageEnglish
    Pages (from-to)630-636
    JournalPlant Physiology
    Volume100
    DOIs
    Publication statusPublished - 1992

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    Hordeum murinum subsp. glaucum
    Paraquat
    paraquat
    Hordeum
    resistance mechanisms
    biotypes
    Herbicides
    herbicides
    Diquat
    Hordeum murinum subsp. leporinum
    Catalytic Domain
    diquat

    Cite this

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    title = "ON THE MECHANISM OF RESISTANCE TO PARAQUAT IN HORDEUM-GLAUCUM AND H LEPORINUM - DELAYED INHIBITION OF PHOTOSYNTHETIC O-2 EVOLUTION AFTER PARAQUAT APPLICATION",
    abstract = "The mechanism of resistance to paraquat was investigated in biotypes of Hordeum glaucum Steud. and H. leporinum Link. with high levels of resistance. Inhibition of photosynthetic O2 evolution after herbicide application was used to monitor the presence of paraquat at the active site. Inhibition of photosynthetic O2 evolution after paraquat application was delayed in both resistant biotypes compared with the susceptible biotypes; however, this differential was more pronounced in the case of H. glaucum than in H. leporinum. Similar results could be obtained with the related herbicide diquat. Examination of the concentration dependence of paraquat-induced inhibition of O2 evolution showed that the resistant H. glaucum biotype was less affected by herbicide compared with the susceptible biotype 3 h after treatment at most rates. The resistant H. leporinum biotype, in contrast, was as inhibited as the susceptible biotype except at the higher rates. In all cases photosynthetic O2 evolution was dramatically inhibited 24 h after treatment. Measurement of the amount of paraquat transported to the young tissue of these plants 24 h after treatment showed 57{\%} and 53{\%} reductions in the amount of herbicide transported in the case of the resistant H. glaucum and H. leporinum biotypes, respectively, compared with the susceptible biotypes. This was associated with 62{\%} and 66{\%} decreases in photosynthetic O2 evolution of young leaves in the susceptible H. glaucum and H. leporinum biotypes, respectively, a 39{\%} decrease in activity for the resistant H. leporinum biotype, but no change in the resistant H. glaucum biotype. Photosynthetic O2 evolution of leaf slices from resistant H. glaucum was not as inhibited by paraquat compared with the susceptible biotype; however, those of resistant and susceptible biotypes of H. leporinum were equally inhibited by paraquat. Paraquat resistance in these two biotypes appears to be a consequence of reduced movement of the herbicide in the resistant plants; however, the mechanism involved is not the same in H. glaucum as in H. leporinum.",
    author = "C Preston and JAM Holtum and Stephen Powles",
    year = "1992",
    doi = "10.1104/pp.100.2.630",
    language = "English",
    volume = "100",
    pages = "630--636",
    journal = "Plant Physiology (Online)",
    issn = "0032-0889",
    publisher = "American Society of Plant Biologists",

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    T1 - ON THE MECHANISM OF RESISTANCE TO PARAQUAT IN HORDEUM-GLAUCUM AND H LEPORINUM - DELAYED INHIBITION OF PHOTOSYNTHETIC O-2 EVOLUTION AFTER PARAQUAT APPLICATION

    AU - Preston, C

    AU - Holtum, JAM

    AU - Powles, Stephen

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    N2 - The mechanism of resistance to paraquat was investigated in biotypes of Hordeum glaucum Steud. and H. leporinum Link. with high levels of resistance. Inhibition of photosynthetic O2 evolution after herbicide application was used to monitor the presence of paraquat at the active site. Inhibition of photosynthetic O2 evolution after paraquat application was delayed in both resistant biotypes compared with the susceptible biotypes; however, this differential was more pronounced in the case of H. glaucum than in H. leporinum. Similar results could be obtained with the related herbicide diquat. Examination of the concentration dependence of paraquat-induced inhibition of O2 evolution showed that the resistant H. glaucum biotype was less affected by herbicide compared with the susceptible biotype 3 h after treatment at most rates. The resistant H. leporinum biotype, in contrast, was as inhibited as the susceptible biotype except at the higher rates. In all cases photosynthetic O2 evolution was dramatically inhibited 24 h after treatment. Measurement of the amount of paraquat transported to the young tissue of these plants 24 h after treatment showed 57% and 53% reductions in the amount of herbicide transported in the case of the resistant H. glaucum and H. leporinum biotypes, respectively, compared with the susceptible biotypes. This was associated with 62% and 66% decreases in photosynthetic O2 evolution of young leaves in the susceptible H. glaucum and H. leporinum biotypes, respectively, a 39% decrease in activity for the resistant H. leporinum biotype, but no change in the resistant H. glaucum biotype. Photosynthetic O2 evolution of leaf slices from resistant H. glaucum was not as inhibited by paraquat compared with the susceptible biotype; however, those of resistant and susceptible biotypes of H. leporinum were equally inhibited by paraquat. Paraquat resistance in these two biotypes appears to be a consequence of reduced movement of the herbicide in the resistant plants; however, the mechanism involved is not the same in H. glaucum as in H. leporinum.

    AB - The mechanism of resistance to paraquat was investigated in biotypes of Hordeum glaucum Steud. and H. leporinum Link. with high levels of resistance. Inhibition of photosynthetic O2 evolution after herbicide application was used to monitor the presence of paraquat at the active site. Inhibition of photosynthetic O2 evolution after paraquat application was delayed in both resistant biotypes compared with the susceptible biotypes; however, this differential was more pronounced in the case of H. glaucum than in H. leporinum. Similar results could be obtained with the related herbicide diquat. Examination of the concentration dependence of paraquat-induced inhibition of O2 evolution showed that the resistant H. glaucum biotype was less affected by herbicide compared with the susceptible biotype 3 h after treatment at most rates. The resistant H. leporinum biotype, in contrast, was as inhibited as the susceptible biotype except at the higher rates. In all cases photosynthetic O2 evolution was dramatically inhibited 24 h after treatment. Measurement of the amount of paraquat transported to the young tissue of these plants 24 h after treatment showed 57% and 53% reductions in the amount of herbicide transported in the case of the resistant H. glaucum and H. leporinum biotypes, respectively, compared with the susceptible biotypes. This was associated with 62% and 66% decreases in photosynthetic O2 evolution of young leaves in the susceptible H. glaucum and H. leporinum biotypes, respectively, a 39% decrease in activity for the resistant H. leporinum biotype, but no change in the resistant H. glaucum biotype. Photosynthetic O2 evolution of leaf slices from resistant H. glaucum was not as inhibited by paraquat compared with the susceptible biotype; however, those of resistant and susceptible biotypes of H. leporinum were equally inhibited by paraquat. Paraquat resistance in these two biotypes appears to be a consequence of reduced movement of the herbicide in the resistant plants; however, the mechanism involved is not the same in H. glaucum as in H. leporinum.

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    DO - 10.1104/pp.100.2.630

    M3 - Article

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    JO - Plant Physiology (Online)

    JF - Plant Physiology (Online)

    SN - 0032-0889

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