A preliminary study of the role of nickel in enhancing flowering of the nickel hyperaccumulating plant Alyssum inflatum Nyár. (Brassicaceae)

• We investigated if reproductive fitness in A. inflatum is enhanced by Ni.
• We documented survival and the proportion of individuals that flowered.
• We also quantified flower production as an indicator of plant fitness.
• Survival was not affected by the presence of Ni.
• Ni, however, stimulated flowering and may contribute to greater fitness.

Alyssum inflatum is a native of serpentine soils and is able to hyperaccumulate nickel (Ni), but the importance of Ni to reproduction in the species is unknown. We investigated if reproductive fitness is enhanced by Ni in the growth medium, and included a treatment involving a relatively high level of Mg to provide a comparison with elevated levels of another metal. Seedlings were grown in a modified Hoagland solution culture in an inert medium of Perlite and were treated with Ni (100 μM), a high concentration of Mg (5 mM), or under control conditions (solution culture without Ni or the addition of high Mg) for 14 months. We documented survival, as well as the proportion of individuals that flowered. We also quantified flower production as an indicator of plant fitness. Survival was not affected by treatment (87–90% for all treatments), but significantly more Ni-treated plants (63%) flowered compared with Mg-treated (19%) or control plants (12%). In addition, inflorescences per plant, inflorescence length, and number of open flowers per inflorescence were all significantly greater for Ni-treated plants relative to plants from the other treatments. Although high levels of Ni are not essential for growth and reproduction of the species, we suggest that Ni stimulates flowering in A. inflatum and may result in greater fitness for the species on serpentine soils.