Figure 3.

[³⁵S]sulfate uptake and partitioning in Flaveria species. Twenty-day-old seedlings of five Flaveria species were resupplied for 4 h with 0.2 mm [³⁵S]sulfate nutrient solution after 6 d exposure to low sulfate (20 µm sulfate; S20) or adequate sulfate (750 µm sulfate; S750). Sulfate uptake (A) and root-to-shoot translocation (B) were determined by scintillation counting after tissue solubilization. C, Incorporation of [³⁵S]sulfate into sulfate, GSH, Cys, and other compounds was determined by HPLC analysis. Relative [³⁵S] partitioning into shoot sulfate, GSH, Cys, proteins, and other compounds after 4 h of resupply is shown, n = 4. Different letters represent values significantly different at P < 0.05 (Student’s t test).