ISSN:
1399-3054
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
Notes:
Paraquat resistance in the grass weed Hordeum glaucum Steud. has been proposed to result from herbicide sequestration away from the growing points. In the present study, we used roots as a model system to investigate cellular transport of paraquat in resistant (R) and susceptible (S) H. glaucum biotypes. Both time- and concentration-dependent kinetics of paraquat influx across the root cell plasma membrane were similar in the S and R biotype. However, compartmentation analysis indicated greater herbicide accumulation in root vacuoles of the R seedlings. In contrast, the amount of paraquat accumulated in the cytoplasm of S was double that found in R biotype. While paraquat efflux from the cytoplasm back into the external solution was similar in the two biotypes, efflux across the tonoplast from the vacuole back into the cytoplasm was 5 times slower in the R than in the S biotype. At the end of a 48-h efflux period, nearly 7-fold more herbicide was retained in the roots of the R compared with those of the S biotype. These results suggest that paraquat resistance in H. glaucum may be due to the herbicide sequestration in the vacuole.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1399-3054.1997.tb05410.x
Permalink
