Abstract
Cadmium (Cd) is one of toxic heavy metals. To reduce Cd accumulation in crop plants, it is necessary to elucidate mechanisms of Cd transport and accumulation in plants. However, these mechanisms are not fully understood so far. Glutathione (GSH), a low weight tripeptide, is involved in many aspects of metabolism. In our previous work, GSH concentration in the phloem sap increased by Cd treatment. These results suggested that GSH might be playing important roles in controlling Cd transport and accumulation. In this work, we investigated effects of GSH which was administered to specific organs of plants.
Oilseed rape plants were grown hydroponically in a green house for four weeks. After treatment, plants were harvested and Cd contents were measured using an ICP spectrometer. We also employed PETIS (Position Emitting Tracer Imaging System) to visualize Cd distribution in the plants. Time-series images of 107Cd distribution were obtained. Cd content in shoots was drastically reduced when their roots were treated with GSH. However, Cd content in roots did not change. Reduction of Cd transport and accumulation by GSH, administered to roots, was also confirmed by PETIS.
