Ecotypic differentiation in the ultramafic flora of the South Island, New Zealand

Abstract

Abstract Fifteen species were investigated for ultramafic tolerance. Seven showed evidence of ecotypes including 4 indigenous species (Luzula crinita var. petriana, Poa colensoi, Neopaxia australasica, and Cotula pyrethrifolia) and 3 widely naturalised grasses (Agrostis tenuis, Anthoxanthum odoratum, and Lolium perenne). Plants from ultramafic populations achieved higher shoot calcium concentrations on ultramafic soil and John Innes Potting Compost, and maintained lower shoot/root ratios on ultramafic soil than plants from non-ultramafic populations. High residual nickel concentrations in shoots of ultramafic clones grown for up to 15 months on non-ultramafic soil suggest that for some species, a preconditioning period longer than the normal 6–8 weeks is required. No evidence of edaphic ecotypes was found in the woody species Nothofagus solandri var. cliffortioides, Griselinia littoralis, or Leprospermum scoparium.