Effects of Heavy Metal (Pb) Stress on Some Growth Parameters and Chemical Changes in the Soybean Plant (Glycine Max L.)

Abstract

Heavy metals are very important abiotic stress factors that can induce different response mechanisms in plant bodies. These response mechanisms include modifying membrane compositions, generating small molecules and free radicals, and altering antioxidant enzyme activities. In this study, we aimed to determine the effect of lead (Pb), an important heavy metal, on some growth parameters and some important enzyme levels. This study was launched to determine the effects of lead (0, 25, 50, 75, 100 mg L-1) on soybean (Glycine max L.) growth parameters and biochemical responses in a fully controlled aeroponic climate chamber. Growth and biochemical enzyme activity parameters of soybean plants changed under heavy metal stress. The lead content of soybeans increased with high concentrations of the metal in the environment. Lead stress negatively affected plant growth, photosynthetic activity, and chlorophyll content. The negative effect of the heavy metal was greater with increasing Pb doses. Lead application significantly increased antioxidant enzyme activities. In addition, more malondialdehyde (MDA), ascorbate peroxidase (APX), and proline were observed in plants experiencing lead stress compared to control plants. In this study, conditions of tolerance of this species to lead were determined and enzyme activity values were determined.