PHYSIOLOGICAL AND ANTIOXIDANT RESPONSES OF ASPLENIUM SCOLOPENDRIUM TO ELEVATED AMOUNTS OF LEAD IN SOIL.

The heavy metal lead is a persistent environmental pollutant. Our studies were carried out to evaluate physiological response and defensive potential of Asplenium scolopendrium exposed to different concentrations of lead added in soil as lead acetate. Plants were exposed to 0, 250, 500, 1000 and 1500 mg Kg-1 Pb+2 for 3 months. Plants possessed efficient enzymatic antioxidant defense mechanism that played important role in limiting stress. The physiological response of Asplenium scolopendrium was investigated by photosynthesis rate and assimilatory pigments (chlorophyll and carotenoids), while the antioxidant defense was evaluated by catalase activity. After 3 months of influencing, the photosynthesis rate is significantly inhibited by high concentration of lead (1500 mg Kg-1 Pb+2). Lower concentrations of lead not produced significant changes in the intensity of photosynthesis. Chlorophyll and carotenoid contents were not affected significantly by Pb treatment. The activity of catalase noted an increase with increasing amount of lead in the soil (an increase of 30.86% in V4 plants, in presence of 1500 mg Kg-1 Pb+2, compared to the control plants). [ABSTRACT FROM AUTHOR]