Effect of cadmium and magnesium on free amino acids, polyamines and peroxidase enzyme activity in wheat seedlings

The effect of cadmium and combined cadmium and magnesium was examined on wheat seedlings (Triticum aestivum L. cv. Alföld-90). The one-week-old hydroponically-grown seedlings of wheat were exposed to Cd2+ (10−7 M, 10−3 M) and Cd2+ (10−7 M, 10−3 M) + 1 % MgCl2 stresses. The stress effects were followed by changes in free amino acid, polyamine contents and peroxidase enzyme activity in roots and shoots. Free amino acid content was determined by ion-exchange liquid chromatography. Polyamine content was identified by OPLC (overpressured layer chromatography). Peroxidase activity (U/mg protein) was measured by spectrophotometric method. The results showed significant differences between the two organs of the plant (root and shoot) with respect to the biochemical response to the applied stress. The cadmium stress caused the accumulation of proline in both shoots and roots. Magnesium reduced the proline content in the samples treated with cadmium. The magnesium treatment seemed to reduce the negative effects of cadmium in wheat seedlings.