Assessment of Arsenite, Arsenate, and Chromate Phytotoxicity Based on the Activity of Seed Germination and Growth (Root & Shoot) of Various Plant Seeds

ABSTRACT

Effects of different concentrations of arsenite, arsenate, and chromate on seed germination, root length (RL), and shoot length (SL) in four seed types, chosen from preliminary tests with eight seed types, were investigated to assess the toxicity of the tested metals. The sensitivities of the four different seed types toward germination, relative RL (RRL), and relative SL (RSL) varied with each metal. In a comparison, the germination of the seeds was more sensitive to the tested metals than the other chosen endpoints (RL and SL). Arsenite was generally more restrictive to all the endpoints (germination, root, and shoot growth) than arsenate and chromate. Lactuca (garden lettuce) was also generally more sensitive to the tested metals than the other seed types. The correlation between RRL and RSL varied depending on the seed type and metal tested. However, significant correlations (r² > 0.85) of these were observed with Lactuca seeds, which appeared to be an optimal plant with respect to the tolerance of the tested metals. The differences in the toxicities of metals toward different plant species should be taken into account in the bioassessment of metals-contaminated sites. Thus, this study encourages the need to combine the three endpoints of various seeds in the evaluation of toxicities of metals.

Key Words:

• metals
• seed germination
• toxicity
• relative root length
• relative shoot length

ACKNOWLEDGMENTS

This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2011-0026754). Also this research was partly supported by the Basic Research Project of the Korea Institute of Geoscience and Mineral Resources (KIGAM) funded by the Ministry of Knowledge and Economy.