Figure 6.

Correlation between the sulfate to glutathione (GSH) ratio in phloem exudates and the sulfate uptake or the xylem loading of sulfate. The mean value of the sulfate/glutathione ratio in phloem exudates from one poplar line and treatment is plotted against the corresponding mean value of the sulfate uptake rate (A) and rate of xylem loading of sulfate (B). The exponential fits y = −0.22 + 13e^{(−(x − 57)/50)} with χ² = 6.5 and r² = 0.795 (A) and y = 1.9 + 10.9e^{(−(x − 1.1)/1.7)} with χ² = 9.2 and r² = 0.709 were performed with the data from three independent experiments, first wild type plus line ggs28 (▪), second wild type and line ggs 11 (□), and an additional experiment performed with the first wild type (○). FW, Fresh weight.