EFFECTS OF LEAD ACCUMULATION ON PHYSIOLOGICAL PARAMETERS AND NUTRITIONAL ELEMENTS IN SAFFLOWER (Carthamus tinctorius L.) SEEDLINGS

Abstract

Lead, one of the toxic metals with no biological function, is a widely dispersed heavy metal found in many forms in natural resources on earth, and anthropogenic activities continue to increase the concentration of Pb in the environment. In this study, it was aimed to determine the effects of different Pb concentrations (0, 5, 25, and 50 mg/L) on physiological parameters and mineral contents of safflower seedlings grown hydroponically under controlled conditions. After two weeks of Pb application, Pb and macro- (K, Ca, Mg) and micro- (Zn, Fe, Cu) element contents of the seedling parts, as well as photosynthetic pigments, total carbohydrate, total phenolic compound, and malondialdehyde (MDA) contents were determined. There was a dose-dependent increase in the Pb contents of the seedling organs. The highest Pb content was found in the roots and the lowest in the leaves. Lead toxicity has been found to impair nutrient uptake and transport, causing nutrient imbalance. In addition, it was shown that Pb toxicity from the changes in photosynthetic pigment, carbohydrate, and phenolic compound contents caused physiological changes in the seedling tissues. Besides, it clearly revealed that the increase in the amount of MDA triggers oxidative stress, which is the secondary stress caused by Pb toxicity.