Boron Tolerance and Accumulation of Three Freshwater Phytoplankton Species
Boron (B) is an essential element for plant, but it may become toxic when present excessively. Abundant study on boron the toxicity, tolerance, and accumulation has been done with advanced plants, however little has been reported on freshwater phytoplankton. To explore these mechanisms, we cultured three typical freshwater phytoplankton species (Microcystis aeruginosa, Scenedesmus obliquus, and Chlorella spp.) under different boron concentrations. After 96 to 120-hour treatment, we tested the growth rate, boron accumulation amount, boron removal rate, and enzyme activities of the three species. Our results showed all these three species can tolerate up to 20 mg B/L. Their boron tolerant abilities are shown as: Chlorella spp.>M aeruginosa>S obliquus. Under the 10-40 mg B/L treatments, M aeruginosa and Chlorella spp. showed high boron accumulation rates (cell boron concentrations reached around 1 μg/ml). But S obliquus only showed high accumulation when the medium boron was 10-30 μg/L. Under the 10 mg B /L treatments, the boron removal rates of the three species were ranged from 57.6-68.7%. But the removal rates decreased with the increase of boron concentration, which means all the three species have the potential to be applied in the low boron-laden wastewater treatment. The superoxide dismutase (SOD) and nitrate reductase (NR) enzymes of the three species all increased under their half maximal boron concentrations (EC50) relatively, thus suggesting that their self-protective mechanism is triggered under excess boron stress.
Chunguang Liu Xiufen Jia Chen Tong
Key Laboratory of Pollution Processes and Environmental Criteria, Ministry of Education, College of Environmental Science and Engineering, Nankai University,Tianjin 300071, China
国际会议
武汉
英文
55
2011-04-05（万方平台首次上网日期，不代表论文的发表时间）