INDUCTION OF PHYTOCHELATIN (CLASS-III METALLOTHIONEIN) AND INCORPORATION OF COPPER IN TRANSFORMED HAIRY ROOTS OF RUBIA-TINCTORUM EXPOSED TOCADMIUM

Hairy roots of Rubia tinctorum L. were cultured in Murashige-Skoog liq uid medium containing cadmium (Cd) chloride (100 mu mol/L), and the in duction of phytochelatin including desglycyl type (PC) was studied usi ng a high performance liquid chromatograph connected with an inductive ly coupled plasma-atomic emission spectrometer. The total Cd concentra tion in the hairy roots was kept almost constant from days 1 to 14 dur ing Cd exposure, but the portion that was recovered from the supernata nt fraction increased with time. The increase reflected the induction of Cd-binding PC. The PC also contained copper as a metal constituent. When the metal composition in PC induced by Cd was compared in the ha iry roots and the normal root cultures of R. tinctorum, the latter sho wed a notably higher Cu/Cd ratio, mainly due to a lower Cd level.