Inorganic markers profiling in wild type and genetically modified plants subjected to abiotic stresses

Nicotiana is a well characterized genus of Solanaceae. It is widely studied in literature in different research fields, such as biology, environmental chemistry, etc. In this study Nicotiana langsdorffii wilde type plants and transgenic for the rat glucocorticoid receptor gene (GR) or Agrobacterium rhizogenes rolC gene were used to value the effect of exposure to chemical compounds (Cr) and to harsh physical conditions (dryness, heat stress) on the inorganic compositions in plants. Four markers were selected, namely Na, K, Cl− and NO3−. Different procedures of extraction were tested: water permitted to obtain the best conditions for the determination of four selected markers. The analysis was carried out by atomic emission spectroscopy for the determination of the cations; the anions were determined both by ion chromatography and potentiometry: the results obtained by these two techniques and their potentiality were compared. The total cation content (Al, Ca, Cr, Fe, K, Mg, Mn, Na, P, Si and Zn) was also determined. The effect of the genetic modifications on the capacity of the plant to contrast the stress stimuli was valued: the introduction of GR gene seems to greatly reduce the effect caused by the stresses and the adsorption of the inorganic pollutants. The modification with rolC increases the absorption capacity of the plant toward Cr and at the same time reduces its release: this behavior can be exploited in phytoremediation applications.