Chlorate‐resistant rose cells: influx, efflux and reduction of [³⁶Cl]‐chlorate

Abstract

Clones of Rosa damascena Mill. cv. Gloire de Guillan, selected for growth in solid medium containing 56 mM NaClO3, were studied to determine the reason for their resistance to this toxic salt. The cells grew on medium containing nitrate as the only nitrogen source, and they synthesized nitrate reductase (EC 1.6.6.2) in the presence of nitrate. The cells were resistant in the presence of nitrate. However, their resistance was greatly increased by the presence of glutamate in the medium. The cells took up [36Cl]‐ClO3‐ and reduced it to ClO2−, but the fraction of ClO3− that they reduced under our experimental conditions was less than that reduced by wild type. The slower production of ClO2− apparently accounted for the resistance of the cells to ClO3−. We suggest several possible reasons for the low rate of reduction of ClO3−.

Anion uptake in maize roots: Interactions between chlorate and nitrate

“…Characterization of chlorate-resistant mutants has primarily focused on those which are nitrate reductase-deficient. Chlorate-resistant mutants which possess nitrate reductase activity have been identified, and a number of alternative mechanisms of resistance have been discussed (Oostindier-Braaksma and Feenstra 1973, Cove 1979, Murphy et al 1985), There appears to be, however, only two published reports characterizing chlorate uptake mutants. Doddema and Telkamp (1979) reported that a chlorate-resistant, CIO; uptake mutant of Arabidopsis thaliana was impaired in NO; uptake relative to the wild type at higher nitrate concentration ranges.…”