EVIDENCE AGAINST A ROLE FOR PHYTOCHELATINS IN NATURALLY SELECTED INCREASED CADMIUM TOLERANCE IN SILENE-VULGARIS (MOENCH) GARCKE

The production of phytochelatins in roots of both cadmium-sensitive and cadmium-tolerant plants of Silene vulgaris (Moench) Garcke in response to Cd supply was recorded over a 7-day growth period. At the same level of Cd, sensitive plants produced more phytochelatins than tolerant ones. In sensitive roots this higher production of PCs was associated with a higher Cd content within one day. From the third day, however, Cd contents were similar, but the difference in PC production persisted. Exposure to buthionine sulphoximine strongly inhibited the production of phytochelatins in roots during cadmium treatment in both sensitive and tolerant plants, but only affected root growth of sensitive plants. Sensitive plants exhibited a higher Cd uptake, which was manifested in a higher Cd accumulation in the shoot. It is concluded that differential cadmium tolerance mechanism in Silene vulgaris is not due to differential production of phytochelatins.