PARENT SESSION
70 - Metal Pollution: From Exposure to Ecological Effects
8:00 AM to 6:30 PM, Wednesday, 15 May 2002
Exhibition Area

(70-46) Micro-PIXE elemental mapping in the chrysomelid beetle (Chrysolina pardalina) from Ni- hyperaccumulating plant (Berkheya coddii).

Przybylowicz, Wojciech^*,1,2, Mesjasz-Przybylowicz, Jolanta¹, Migula, Pawel³, Glowacka, Elzbieta⁴, Augustyniak, Maria³, Nakonieczny, Miroslaw³, ¹ Materials Research Group, National Accelerator Centre, Somerset West, South Africa² Academy of Mining and Metallurgy, Krakow, Poland³ Department of Animal Physiology and Ecotoxicology, University of Silesia, ul. Bankowa 9, Katowice, Poland⁴ Department of Zoology,, University of Silesia, ul. Bankowa 9, Katowice, Poland

ABSTRACT- Ch. pardalina has been recognised as a potent pest, able to control distribution of Ni hyperaccumulating Berkheya coddii. Elemental maps were used here as a tool, in a search for possible mechanisms allowing Ch. pardalina a successful development under metal stress. Beetles were collected in Agnes Mine and Groenvaly (Mpumalanga, South Africa) and fed with fresh B. coddii leaves. Analyses were performed with 6 MeV protons using the nuclear microprobe at the National Accelerator Centre, SA. Beam sizes were 1-2 m for proton currents of 100 pA. Elemental maps and determinations of Ni, Cl, K, Ca, Ti, Cr, Mn, Fe, Fe, Co, Cu, Zn, Br, Rb, Rb and Sr were done in freeze-dried dissections of adult beetles with emptied digestive tract: gut, Malpighian tubules, neural ganglia and nerves, brain, ovaries, testes, seminal duct, oviduct, haemolymph, cuticle, eggs, and larval/pupal exuviae. Ch. pardalina is able to utilise plant material due to effective Ni elimination from their gut. The BAF for Ni in adult beetles was 0.009 (431 ±81g Ni g^-1 body weight). Majority of Ni was found in Malpighian tubules, the structures responsible for the elimination of excess nickel from the haemolymph. There was also differentiation in its content in the gut, with the highest concentration in the intestine. A uniform distribution pattern for Ni and other bivalent elements characterised reproductive organs and neural structures, indicating a strong protection of these structures against excess of Ni. Elemental maps showed a series positive correlations between bivalent metals (e.g. Ni and Zn), especially in the Malpighian tubules and in the gut. Exocuticle maps demonstrated also its importance in Ni-elimination during consecutive phases of larval development.

Key words: Nuclear microprobe, Chrysolina pardalina, Hyperaccumulation, Nickel