Zinc tolerance and hyperaccumulation in F-1 and F-2 offspring from intra and interecotype crosses of Thlaspi caerulescens

International audienceThe relationship between zinc (Zn) tolerance and hyperaccumulation in Thlaspi caerulescens was investigated from F-1 and F-2 crosses within and among metallicolous and nonmetallicolous Mediterranean populations. F-1 offspring were grown on increasingly Zn-enriched soils to test Zn enrichment effects, and many families of F-2 offspring were grown on a Zn-rich soil. Tolerance of F-1 offspring depended on stress intensity. Tolerance of interecotype crosses was intermediate between that of the intraecotype crosses. No difference in Zn accumulation appeared among the F-1 offspring from the three crosses involving metallicolous parents. Otherwise, none of these offspring exceeded the Zn hyperaccumulation threshold (10 000 mg kg(-1)), unlike the nonmetallicolous ones. The latter also showed the highest mortality. In some F-2 families from interecotype crosses, hyperaccumulation values exceeded 15 000 mg kg(-1) in nontolerant offspring, whereas tolerant offspring displayed lower values (c. 10 000 mg kg(-1)). There was no difference between tolerant and nontolerant offspring when they showed low hyperaccumulation. Therefore, the relationship between tolerance and hyperaccumulation in F-1 and F-2 crosses depended on the hyperaccumulation level of plants