Nuclear microprobe studies of elemental distribution in seeds of Biscutella laevigata L. from zinc wastes in Olkusz, Poland

Biscutella laevigata L. (Brassicaceae), a rare perennial metallophyte plant species known mainly from Central and Southern Europe, has a very restrict ed distribution in Poland. This investigation focuses on one known Polish l owland location of B. laevigata on zinc dumps near Olkusz, Upper Silesia. T he results presented are a continuation of earlier studies, undertaken to u nderstand mechanisms of plant adaptation to a hostile environment, rich in heavy metals. The analyses were performed with 3.0 MeV protons, using the N ational Accelerator Centre (NAC) nuclear microprobe. Two complementary tech niques, proton-induced X-ray emission (PIXE) and proton backscattering spec trometry (BS), were simultaneously used. Quantitative elemental maps showed that seed tissue was defined by specific elemental allocation patterns. Th e highest concentration of Zn and other heavy metals was found in the endos perm. Within embryonic tissue, the highest amount of Zn was found in the ra dicle. Mapping artefacts, related to specimen shape, are discussed. The res ults show that plants strictly and actively select elements and their amoun ts taken up by different tissues. This mechanism is probably responsible fo r their survival. (C) 2001 Elsevier Science B.V. All rights reserved.