Distinctive effects of cadmium on glucosinolate profiles in Cd hyperaccumulator Thlaspi praecox and non-hyperaccumulator Thlaspi arvense

The influence of Cd on growth, Cd accumulation and glucosinolate (GS) contents was investigated in Thlaspi praecox in comparison to Thlaspi arvense. Accumulation of up to 2,700 mu g Cd g(-1) dry weight in shoots of T. praecox, growing in nutrient solution with 50 mu M Cd without growth inhibition, confirmed this species as a Cd-hyperaccumulator. Cadmium increased the level of total GS in T praecox without a statistically significant influence on total sulphur. This increase in GS was due to the enhancement of benzyl-GS, mainly sinalbin. In the Cd sensitive T arvense Cd caused a shift from alkenyl-GS, mainly sinigrin, to indolyl-GS. The Cd-induced increase of total GS in T. praecox indicates that in this species Cd hyperaccumulation is not linked to trade-off of organic defences. The distinctive influence of Cd on GS profiles in Cd-sensitive T arvense and Cd-tolerant T. praecox favouring indolyl-GS and benzyl-GS, respectively, is discussed in relation to jasmonate and salicylate as possible key molecules in Cd-stress transduction in these contrasting Thlaspi species.