The effect of different concentrations of lead on some physiological parameters in two populations of Harmal (Peganum harmala L.)

Aim: The aim of the present study was to investigate the effect of lead concentrations on the growth, antocyanin, chlorophyll, carotenoid, total soluble sugars, reducing sugars and free amino acids of harmal (Peganum harmala L.) populations.
Material and Plants of two different Peganum harmala populations (metallicolous and non metallicolous) were grown in hydroponic condition. Then plants were exposed to 0, 5, 10, 25 and 50 ppm Pb for 14 days. Finally, parameters were measured and calculated by spectrophotometer.
Results showed that the increase of Pb concentrations in the nutrient solution reduced root length and there were significant difference between two populations. Chlorophylls and carotenoid pigments were generally decreased by Pb concentrations, especially under the highest Pb treatment (50 ppm) in both populations. Anthocyanin, total soluble sugars and free amino acids were increased in both populations.
The higher amounts of anthocyanin, total soluble sugars and free amino acids in metallicolous population reflecting the higher degree of tolerance to Pb in this population.