Uptake and accumulation and oxidative stress in garlic (Allium sativum L.) under lead phytotoxicity.

The effects of different concentrations of Pb on growth of Allium sativum L, Pb uptake and accumulation, antioxidant enzyme activity and malondialdehyde content were investigated. The results indicated that shoot growth at high concentration of Pb (10(-3) M) and roots growth at 10(-3) M and 10(-4) M Pb were significantly inhibited. Lead ions were accumulated mainly in the roots and only small amounts were translocated to bulbs and shoots. SOD activities in shoot and roots exposed to 10(-3) M Pb were observed to be high. Plants exposed to 10(-3) M Pb showed a significant increase in POD activity in roots versus the control and other Pb treatments. In roots, CAT activity and MDA concentration at 10(-3) M Pb is high significantly. The mechanisms of Pb toxicity and tolerance in garlic are briefly discussed.