Fig. 7.

Non-protein thiols, total sulphur, and free sulphate content in the mutants versus the wild type. (A, B) 7-d-old sue4 and the wild type were transplanted from MS hydroponic medium (Normal) to sulphate-free hydroponic medium (Sulphur-free) for 48 h before tissue extracts were prepared for quantification of GSH and cysteine. Three replicate experiments were conducted for each treatment. Error bars represent SEM. *0.05<P <0.01, **P <0.01, ***P <0.001. (C) Total sulphur content of seedlings and seeds. Seeds of the wild type and the mutants were germinated on the MS or low-sulphur medium (75 μM sulphate) for 4 d, then transplanted into MS medium (Normal) or sulphur-free medium (Sulphur-free) for 10 d before quantifying total sulphur content. Air-dry wild-type and mutant seeds were directly quantified for total sulphur content (Seed). For each treatment, three replica experiments were used and error bars represent SEM. *0.05<P <0.01, **P <0.01, ***P <0.001. (D) Free sulphate content. Seeds of the wild type and the mutants were germinated on the MS or low-sulphur medium (75 μM sulphate) for 7 d, respectively. MS medium-germinated seedlings were transferred to soil and grew for 42 d before free sulphate quantification (Normal). Low-sulphur medium-germinated seedlings were transferred to sulphur-free hydroponic medium and grew for 42 d before free sulphate quantification (Sulphur-free). For each treatment, three replica experiments were used and error bars represent SEM. *0.05< P < 0.01, **P <0.01, ***P <0.001.