The physiological analysis of cadmium binding compound in the stem of reed

Abstract

Reed ( Phagmites communis ) is highly tolerant to cadmium. The cadmium concentration of leaf was one-third of that of stem after 7 d exposure to 100μM CdCl₂. Half of the total cadmium in the stem localized in cell wall and another half in subcellular. These results suggest that the stem of reed has detoxication mechanism to intracellular cadmium. Cadmium in the stem was found in the fraction of MW < 3000 and 10000 to 50000, and the cadmium complexes in MW 10000 to 50000 fraction were not thiol compounds. On the other hand, the sugar content of MW 10000 to 50000 was increased in response to cadmium stress. These results suggest that the stem of reed produce non-thiol sugar compound binding to cadmium in response to cadmium stress, thus reed could accumulate cadmium in stem and keep low concentration in leaf.