title: The possible role of metallothioneins in copper tolerance of Silene cucubalus.
abstract: Growth and copper-binding of a copper-tolerant and a copper-sensitive population of Silene cucubalus (L.) Wib. have been studied. The copper-tolerant plants showed a much lower uptake and a proportionally higher transport of copper from root to shoot. A copper-binding protein with an apparent Mr of 8500 resembling metallothionein has been isolated from the roots of copper-treated plants of the tolerant population. After 20 d, the protein was observed to be inducible upon copper supply in the copper-tolerant plants, but not yet in the sensitive ones. This could be an indication of a difference in metalregulated synthesis of the protein. Ion-exchange chromatography of the 8500 protein yielded a major copper-containing fraction eluting at high ionic strength. Other characteristics such as UV absorption and amino-acid composition resembled strongly those of metallothioneins. The involvement of metallothioneins in the detoxification of copper within Cu-tolerant plants is discussed in relation to other mechanisms.
authors.affiliation: Department of Ecology, Biological Laboratory, Free University, P.O. Box 7161, NL-1007 MC, Amsterdam, The Netherlands.
authors.forename: P C
authors.initials: PC
authors.lastname: Lolkema
authors.forename: M H
authors.initials: MH
authors.lastname: Donker
authors.forename: A J
authors.initials: AJ
authors.lastname: Schouten
authors.forename: W H
authors.initials: WH
authors.lastname: Ernst