Aims Thallium hyperaccumulation has previously been observed in the field but there are no laboratory confirmations for Biscutella laevigata. Tolerance and accumulation of thallium and its chemical analogue caesium were compared in one non-metallicolous and three metallicolous (calamine) populations of the candidate Tl hyperaccumulator species, B. laevigata. Methods Tolerance and accumulation were evaluated in hydroponics. Moreover, Tl and Cs accumulation were measured at different K concentrations in the nutrient solution. Seedlings were also grown in Tl contaminated calamine soil. Results Estimated from their root growth response, all the calamine populations showed hypertolerance to Tl, although to very different degrees. Foliar Tl hyperaccumulation from hydroponics and soil was apparent in two populations. In one of them, it was a highaffinity phenomenon, but it was only apparent at high Tl exposure levels, and not associated with enhanced root-to-shoot translocation in the other one. There was no considerable inter-population variation in Cs tolerance and accumulation, except that one population showed a relatively low Cs retention in its roots under low exposure. Conclusions Tl hyperaccumulation and hypertolerance are population-specific traits in B. laevigata. Cs accumulation and tolerance are less variable and largely uncorrelated with Tl accumulation and tolerance.
Hyperaccumulation of thallium is population-specific and uncorrelated with caesium accumulation in the thallium hyperaccumulator, Biscutella laevigata
MARCHIOL, Luca;
2013-01-01
Abstract
Aims Thallium hyperaccumulation has previously been observed in the field but there are no laboratory confirmations for Biscutella laevigata. Tolerance and accumulation of thallium and its chemical analogue caesium were compared in one non-metallicolous and three metallicolous (calamine) populations of the candidate Tl hyperaccumulator species, B. laevigata. Methods Tolerance and accumulation were evaluated in hydroponics. Moreover, Tl and Cs accumulation were measured at different K concentrations in the nutrient solution. Seedlings were also grown in Tl contaminated calamine soil. Results Estimated from their root growth response, all the calamine populations showed hypertolerance to Tl, although to very different degrees. Foliar Tl hyperaccumulation from hydroponics and soil was apparent in two populations. In one of them, it was a highaffinity phenomenon, but it was only apparent at high Tl exposure levels, and not associated with enhanced root-to-shoot translocation in the other one. There was no considerable inter-population variation in Cs tolerance and accumulation, except that one population showed a relatively low Cs retention in its roots under low exposure. Conclusions Tl hyperaccumulation and hypertolerance are population-specific traits in B. laevigata. Cs accumulation and tolerance are less variable and largely uncorrelated with Tl accumulation and tolerance.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
