Response to cadmium in carrot in vitro plants and cell suspension cultures

In vitro grown plants and cell suspension cultures of carrot (Daucus carota L.) were treated with various Cd concentrations. Stress ethylene production in carrot plants was highly stimulated by 1 mM Cd. A pre-treatment with buthionine sulfoximine (BSO) did not further increase ethylene production. After being treated with Cd, both plants and cell suspensions produced phytochelatins, and no lipid peroxidation was detected. In cell cultures, the in vitro activity of phytochelatin synthase was assayed in the presence of Cd and glutathione: the first product (PC2) was detected in less than 30 min. Absence of ethylene (after treatment with aminoethoxyvinylglycine (AVG), an inhibitor of ethylene-biosynthesis, or use of ethylene traps) caused both a decrease in the phytochelatin synthase activity of cell suspensions and a strong lowering in the Cd-induced SH groups in plants. However 1-aminocyclopropane-1-carboxylic acid (ACC) supply did not increase either phytochelatin synthase activity or total SH level. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.