Morphological and Physiological Effects of Lead Application on Peanut (Arachis hypogaea L.)

Abstract

This study was carried out to etermine some morphological and hysiological effects of lead heavy metal on peanut (Arachis hypogaea L.). The study was conducted in a climate chamber, under controlled conditions, and in soilless culture according to randomized complete blocks design. Lead concentrations of 0, 10, 100, and 1000 mg L-1 were applied to peanut (A. hypogeae L. cv. Sultan). According to the results of the study, the Pb content of the root, stem, and leaves of the peanut seedlings increased due to the increasing Pb concentration. Lead content in seedlings followed a pattern of root>stem>leaf. Plant root and stem lengths as well as fresh weights of root, stem, and leaf decreased as lead concentrations increased. In addition, Pb concentrations reduced phenolic compounds in root, stem, and leaf. Also, the photosynthetic pigment amounts of the leaves decreased under Pb toxicity. It was determined that the applied lead concentrations caused oxidative stress in the cell membranes of peanut seedlings and the amount of malondialdehyde increased in the root, stem, and leaves. In general, reductions in protein amounts were determined in all parts of seedlings. The amount of proline amino acid in the root and stem was generally decreased compared to the control group, while it was increased in the leaves, especially at 100 and 1000 mg L-1 concentrations, ndicating that this amino acid may have some role against Pb toxicity in the leaves. As a result, it was determined that high doses of lead have toxic effects on peanut seedlings.

Keywords

• arachis hypogeae
• lead
• heavy metal
• phenolic compounds
• proline
• toxic effect