Uranium accumulation and tolerance in Arabidopsis halleri under native versus hydroponic conditions

Comparisons of uranium (U) accumulation and tolerance were conducted in terrestrial versus laboratory trials using an endemic, on a former U mining site growing Arabidopsis halleri.
Sequential extractions combined with ICP-MS measurements were used for determining the soil content of different metals and the U accumulation in plants, respectively. Root elongation tests, investigations of photosynthetic traits via absorption and fluorescence spectroscopy enabled estimations of U tolerance.
Hydroponically grown plants accumulated 100 fold more U in roots and 10 fold more in shoots compared with plants growing in their native habitat. Despite this elevated U uptake, the root elongation was not affected. However, impairments of the photosynthetic machinery could clearly be proven.
These facts are important indications for a pronounced decreasing U tolerance under laboratory conditions. The occasional different bioavailability of U and essential metals such as iron in the two approaches is one of the key factors affecting U accumulation, transport, tolerance or toxicity development. The described “uranophyte” Arabidopsis halleri could be a versatile tool for such unequal objects.