Fig. 10.

Sulphate (1), phosphate (2), glutathione (3), and sucrose (4) contents in xylem sap (A) and phloem exudates (B) of poplars treated with sulphur depletion and of control plants (day 0). Data presented are the means ±SD of five replicates where each replicate consisted of two pooled plants. Lower case letters indicate significant differences at P < 0.05 between different time points within one tissue. Contents were related to litres of xylem sap or bark fresh weight (fw) of the bark piece used for phloem exudation, respectively. n.d., not detected