Effects of glutathione concentration in the root zone and glutathione treatment period on cadmium partitioning in oilseed rape plants

Nakamura, Shinichi*; Kondo, Hikari*; Suzui, Nobuo; Yin, Y.-G.; Ishii, Satomi; Kawachi, Naoki; Rai, Hiroki*; Hattori, Hiroyuki*; Fujimaki, Shu

Glutathione is a sulfur-containing peptide involved in various aspects of plant metabolism. Glutathione is also known to have effects on heavy metal responses in plants. In our previous work, we have found glutathione, applied to roots site- specifically, inhibited cadmium (Cd) translocation from roots to shoots and Cd accumulation in shoots in oilseed rape plants. In addition, we succeeded in visualizing inhibition of root-to-shoot translocation of Cd by using a positron-emitting tracer imaging system (PETIS). In this work, the effects of glutathione concentration in the root zone (hydroponic solution) and the glutathione treatment period on Cd partitioning in oilseed rape plants were investigated. Our experimental results demonstrated that glutathione, exceeding a certain concentration in the root zone, is needed to trigger inhibition of Cd translocation, and that treatment time from the start of glutathione application had different effects on Cd partitioning in oilseed rape plants.