Fig. 3.

GSH contents in the six different root fractions of 8-week-old poplar plants girdled for different periods of time at the transition between stem and root. c_120 indicates an additional control harvested at day 5 after starting the experiment. Data given are mean values ±SD from three plants at the time indicated. (a) Indices indicate significant differences between the six root fractions during one harvest time at P <0.05; (A) indicates significant differences between sampling dates along one root fraction at P <0.05. The absence of indices indicated that significant differences were not found.