Reaction norms of life history traits in response to zinc in Thlaspi caerulescens from metalliferous and nonmetalliferous sites

Summary•  We examined phenotypic plasticity of fitness components in response to zinc (Zn) in the Zn hyperaccumulator, Thlaspi caerulescens . •  Two populations from Zn‐enriched soils (M) and two populations from normal soils (NM) were grown in pots at three Zn concentrations (0, 1000 and 8000 mg kg −1 Zn), for an entire life cycle. Growth, Zn accumulation and fitness components were assessed. •  Based on vegetative growth, M and NM populations had similar Zn tolerance at 1000 mg kg −1  Zn. However, reproductive output was markedly decreased in NM at 1000 and 8000 mg kg −1  Zn. In M populations, Zn did not affect fitness. However, low Zn status enhanced reproductive output in year 1 compared with year 2 and decreased survival after the first flowering season. •  M populations are able to achieve equal fitness across a broad range of Zn concentrations in soil by different combinations of fecundity and longevity. No cost of higher tolerance was demonstrated in M populations. Reproductive traits appeared to be a more sensitive indicator of tolerance than vegetative growth.