The amount of cadmium associated with Cd-binding protein in roots of Agrostis gigantea, Maize and tomato

Abstract

Roots retained a major portion of the Cd in seedlings exposed to 0.5–6 μM Cd in nutrient solutions. The Cd-binding (CdBP) protein of tomato did not account for the early retention of Cd by roots, since the protein only appeared at 7 days. The percentage of root Cd in CdBP increased over 7 days to 11–34% in Agrostis gigantea clone 4 and to 28–71% in maize. Cd toxicity occurred in both species. Clone 6 of A. gigantea sequestered 21–68% of the root Cd in CdBP protein after 1 day of excess Cd and maintained a high percentage through to day 7. No Cd toxicity was manifested. Only the specific response pattern observed in plants of clone 6, the rapid, early and sustained production of CdBP, was consistent with a detoxification role for CdBP.