Comparison of iron localization in wild plants and hydroponic cultures of Imperata cylindrica (L.) P. Beauv.

A complete study of the distribution and localization of metals, especially iron, in the Fe hypertolerant, Imperata cylindrica, in its natural habitat from Rio Tinto riverbeds and in controlled laboratory conditions has been carried out. Different analytical (ICP-MS (inductive coupled plasma mass spectrometry) and microscopic techniques such as OM (optical microscopy) with histochemical staining (Prussian Blue stain formation for iron staining), SEM and TEM (scanning and transmission electronic microscopy) coupled with EDX (energy dispersive X-ray) have been used to analyze the plant organs and tissues. The Fe accumulation and biomineralization capacities of I. cylindrica are corroborated in both wild and controlled laboratory conditions. Fe accumulation was found in the cell walls and intercellular spaces of most of the tissues, excluding sclerenchyma cells, of every plant vegetative organ and endodermis of root cells. Jarosite and Fe-oxides were observed in both wild and treated samples. Moreover greenhouse treated plants have the same Fe distribution pattern as wild plants, though differences in their nutrient and metal concentrations are observed. The Prussian blue staining combined with the microscopic techniques here used is an effective method for the analysis of Fe in hypertolerant plants.