Poster: Ecophysiology

Abs # 11: Intraspecific Variation in the Cellular Partitioning of Metals in the Zn/Cd Hyperaccumulator Thlaspi caerulescens

Presenter:	Krasnyanski, Sergei F, ksergei@siu.edu
Authors	Krasnyanski, Sergei F (A)   Ebbs, Stephen  (A)
Affiliations:	(A): Southern Illinois University

A relatively understudied aspect with respect to hyperaccumulators is the natural variation in metal hyperaccumulation and tolerance observed between populations within a species. The inherent variability in hyperaccumulation of Zn and Cd displayed by natural populations of Thlaspi caerulescens and their unique patterns of metal distribution (e.g. – epidermal and vacuolar sequestration) in leaves provide a natural model system in which to examine the leaf-level mechanisms involved in metal allocation and hyperaccumulation. Understanding the basis of this variation will provide information that can be incorporated into ongoing efforts to develop more efficient hyperaccumulators for metal phytoremediation and metal “bio-mining”. The current research is examining the contribution of mesophyll cell-level tolerance mechanisms and apoplastic loading to hyperaccumulation. A proteomic approach is also being utilized to search for novel proteins involved in hyperaccumulation and tolerance in hyperaccumulators. Concurrent efforts are underway to clone and characterize genes encoding various membrane transport proteins in these species to relate the physiological results to their underlying genetic mechanism. Together the results of this study will add to our understanding of the relationship between metal distribution in leaves and the extent to which different populations of T. caerulescens hyperaccumulate Cd and Zn. This unique insight into the metal dynamics in leaves will be instrumental in the development of higher biomass plants for phytoremediation.