Toxic effect of tetracycline exposure on growth, antioxidative and genetic indices of wheat (Triticum aestivum L.).

ABSTRACT

INTRODUCTION: More attention has been paid to tetracycline contamination in view of its rapid increasing concentration in the environment. Therefore, it is important to set up rapid, simple, and accurate methods for monitoring tetracycline ecotoxicity. METHODS: In the present study, a hydroponics experiment was conducted to examine toxic effects of tetracycline at the concentration range of 0.5 to 300 mg L(-1) on growth, antioxidative, and genetic indices of wheat (Triticum aestivum L.). RESULTS: The results indicated that tetracycline at 0.5-10 mg L(-1) could stimulate seed germination, cell mitotic division, and growth of wheat seedlings and did not induce a significant increase in the activity of antioxidative enzymes. However, tetracycline at the high concentrations (10-300 mg L(-1)) could significantly inhibit these parameters in the concentration-dependent manner, including germination percentage (≥100 mg L(-1)), shoot height (≥100 mg L(-1)), root length (≥50 mg L(-1)), and mitotic index (≥50 mg L(-1)), and increased the activity of antioxidative enzymes (≥25 mg L(-1)) in the dose-dependent manner, including superoxide dismutase, catalase, and peroxidase. Tetracycline at 5 mg L(-1) and above significantly augmented chromosome aberration frequency and malondialdehyde (MDA) content. On the other hand, MDA has positive correlation with the inhibition rates of seed germination, root length, shoot length, mitotic index, and antioxidative enzyme activities. CONCLUSION: Tetracycline may have potential physiological, biochemical, and genetic toxicity to plant cells, and chromosome aberration and MDA might be sensitive bioindicators for tetracycline contamination than the other plant characteristics.