TRACE ELEMENTS IN A NEW ZEALAND SERPENTINE FLORA

The trace element content of ashed specimens of a New Zealand serpentine flora and the associated soils was investigated. Six species (Myosotis monroi Cheesem., Notothlaspi australe Hook. f., Pimelea suteri Kirk, Cassinia vauvilliersii (Homb. et Jacq.) Hook. f. var serpentina Ckn. et Allan, Hebe odora (Hook, f.) Ckn. and Leptospermum scoparium J. R. et G. Forst.) were analysed for cobalt, chromium, copper and nickel by emission spectroscopy. The significance of the experimental data was evaluated by calculation of the correlation coefficients by a computer. C. vauvilliersii showed highly significant correlation between plant ash and soil concentration for chromium, cobalt and nickel. H. odora and L. scoparium showed similar but less pronounced correlations. Relative concentrations varied considerably among the species studied. P. suteri is a strong accumulator of nickel and cobalt and L. scoparium of chromium. Good correlations were observed for certain pairs of elements in the plant ash of individual species and in the soils alone. Data for uptake by plants were compared with soil extractabilities. Calcium-magnesium ratios were also determined, and were found to be much lower than in the same species growing on non-serpentinized soils. It was concluded that the above species, particularly C. vauvilliersii will be useful in biogeochemical prospecting.