Jornal de Biorremediação e Biodegradação

Abstrato

Estimation of the Seedling Vigor Index of Sunflowers Treated with Various Heavy Metals

Xin Zhao, Jin Chul Joo, Dongwook Kim, Jung-Kul Lee and Jae Young Kim

In order to quantitatively describe the relative effect of the concentrations of heavy metals (i.e., Cd, Pb, Zn, and Ni) on the germination and seedling growth of plants, the seed germination tests were conducted using sunflower seeds treated with various heavy metals, and a mathematical model to estimate the seedling vigor index (SVI) is proposed. From the results of germination tests, a decrease in the seed germination percentage with an increase in the heavy metal concentration was observed, and the inhibitions of seedling growth were clearly detectable above certain critical concentrations (e.g., 50 mg-Cd/l, 50 mg-Ni/l, 100 mg-Zn/l, and 1,000 mg-Pb/l). According to both the IC50 and a1 values, the resulting order of phytotoxicity for the heavy metals on sunflower seed germination was Cd>Ni>Zn>Pb. The SVI estimation model developed in this study rigorously explained the relationship between the heavy metal concentration and the SVI values. Thus, SVI values for a certain plants can be, a priori, obtained, with the heavy metal concentrations in the aqueous phase without performing the germination tests. Although the coefficients of SVI estimation model changed from different species of plants, the empirical SVI estimation model derived from theoretical background can be utilized for other species of plants.