SURVIVAL OF ACER-PSEUDOPLATANUS L (SYCAMORE) SEEDLINGS ON METALLIFEROUS SOILS

Seeds and seedlings of Acer pseudoplatanus L. (sycamore) were collecte d at sites contaminated by metals, originating either from mining spoi l or from aerial deposition from metal processing industry, and at a n umber of relatively uncontaminated sites. Seedling growth was examined in relation to site of origin, both in nutrient solutions with elevat ed metal concentrations and in reciprocal transplant experiments in so ils from the sites. Metal tolerance was not detected and there was no significant difference between plants from the different sites of orig in. It was found, however, that roots could proliferate in uncontamina ted zones of the soil and that, even in contaminated soils, most seedl ings used in growth tests survived for at least three years despite im paired growth. Seedlings growing at the contaminated sites showed phyt otoxic symptoms associated with high metal levels, but apparently heal thy seedlings and saplings of different ages were also found. Some for m of low level innate tolerance may be involved but it is suggested th at phenotypic plasticity is more important than previously thought, po tentially allowing survival until favourable conditions are encountere d either temporally or spatially.