Toxic Effects of Lead on Growth and Some Biochemical and Ionic Parameters of Sunflower (Helianthus annuus L.) Seedlings

Abstract: Lead (Pb) is one of the non essential and toxic heavy metals which can cause oxidative stress in plants. The effects of Pb(NO 3 ) 2 toxicity on growth and some biochemical parameters of record cultivars of Helianthus annuus L. were studied under hydroponic condition. Different treatments of Pb(NO 3 ) 2 [control (0), 200, 400, 600 and 800 :M] were used in order to consider changes in dry weight, proline and Pb accumulation in roots and shoots; Total chlorophyll, enzyme activity (catalase and peroxidase) and K + , Ca 2+ amounts of leaves. Compared with the control, Pb treatment caused a significant decrease in roots and shoots dry weight, leaves chlorophyll, catalase activity and K + , Ca 2+ amounts. In contrast, a significant increase in proline and Pb accumulation of roots and shoots and peroxidase activity of leaves was observed in Pb treatments

The Effects of NaCl Stress on the Physiological and Oxidative Situation of Maize (Zea mayz L.) Plants in Hydroponic Culture

Abstract: The effects of NaCl salinity on biomass, Malondialdehyde (MDA), peroxidase (POD), Catalase (CAT), Na + , K + , Ca 2+ and proline in Zea mays L. seedlings were investigated under hydroponic condition. Seedlings were subjected to NaCl stress (0, 50, 100, 150 and 200 mM) for 14 days. A completely randomized design with four replicates for each treatment was used. Salinity stress affected on the growth and caused a reduction in root and shoot biomass. NaCl treatment caused a significant increase in root MDA content. NaCl at 100 mM and higher increased also the shoot MDA content significantly. Catalase activity of leaf was significantly increased at 100, 150 and 200 mM NaCl in comparison with the control. Peroxidase activity in leaf started to significant increase with the rise of NaCl content at 150 and 200 mM. The leaf Na + content, root and shoot proline concentrations increased with the increase in salinity stress. The leaf K + and Ca 2+ amounts were significantly decreased with the rise of salinity stress in comparison with control