Figure 6.

[³⁵S]sulfate uptake and partitioning in interspecies grafts of F. robusta and F. bidentis in dependence on the nutrient regime. Seedlings of F. robusta (C₃) and F. bidentis (C₄) were grafted 5 d after germination. 35 d after grafting, the grafted plants were resupplied for 4 h with 0.2 mm [³⁵S]sulfate nutrient solution after 6 d exposure to low sulfate (20 µm; S20) or adequate sulfate (750 µm; S750). A, Total [³⁵S]sulfate uptake. B, Total shoot GSH concentration in S-starved (S20), resupplied, and fully nourished (S750) grafts. Data are shown as box plot (25–75%); the line represents median, and the whiskers represent 1.5 IQR, n = 4. C, Relative [³⁵S]sulfate partitioning into shoot sulfate, GSH, Cys, proteins, and other compounds after 3 h of resupply. Different letters represent values significantly different at P < 0.05 (Student’s t test), n = 4.