Phenotyping 60 populations of Noccaea caerulescens provides a broader knowledge of variation in traits of interest for phytoextraction

Abstract

Noccaea caerulescens is a model plant for understanding metal hyperaccumulation as well as being a potential source of cultivars for phytoextraction. Sixty populations from non-metallicolous (NM), calamine (CAL) and serpentine (SER) edaphic groups were phenotyped in order to more extensively characterise the species and to detect candidates for cultivar selection. 15 plants per population were grown until fruit maturity in a greenhouse on a homogeneous soil spiked with Cd, Ni and Zn. Development, growth and ionome variables were measured. NM and SER edaphic groups seem to be similar, with plants producing fewer inflorescences and shoot biomass, flowering later, reaching maturity sooner and accumulating more transition metals than CAL plants. Three geographically structured CAL subgroups could be distinguished according to their shoot Cd/Zn ratio. Only CAL populations from the south east of the Massif Central were observed to hyperaccumulate Cd. At the species level, the Ni and Zn contents were strongly correlated. Nickel accumulation was also closely associated to that of Mg and Ca. The NM and SER edaphic groups both hyperaccumulated Ni and Zn. Biomass production was not correlated to metal contents, suggesting no trade-off between these traits. The high natural variability of N. caerulescens’ traits and its accumulation potential could be exploited for the production of phytoextraction cultivars.