聚生角毛藻、小球藻对砷和磷的分辨

THE ABILITY OF CHAETOCEROS SOCIALJS LAUDERS AND CHLORELLA SP. TO DISCRIMINATE BETWEEN PHOSPHATE AND ARSENATE

通过藻类培养实验,表明福建九龙江河口藻类优势种聚生角毛藻(Chaetoceros socialis Lauders)和广盐种小球藻(chlorella sp.)对砷酸盐和磷酸盐具有分辨能力。用^(14)C和^(32)P示踪方法测得不同浓度砷(5—40μg/L)对这两种藻类的光合作用和吸收磷的速率均不产生影响。即使在磷几乎耗尽的情况下,该浓度范围砷对两种藻既不产生毒性效应,也不能代替磷酸盐维持藻细胞的生命活动。

Based on the laboratory culture experiments, it was found that Chaetoceros socialis Lauders and Chlorella sp. were capable of discriminating between phosphate and arsenate ions in seawater medium. Neither reduced nor methylated arsenic species were detected in the medium during the culture experiments. The arsenate levels remained essentially constant even when the phosphate levels became depleted. The degree of phosphate/arsenate discrimination factor D varied from 4 to 16 with external arsenate concentrations 5-35μg/L, and a linear correlation between discrimination factor D and arsenate concentration was obtained. It was found that the external arsenate concentrations (5-40μg/L) had no significant effect on the growth, photosynthesis rate and uptake rate of phosphate of Chaetoceros socialis Lauders and Chlorella sp,. whereas the photosynthesis rate and uptake rate of phosphate were determined by 14C and 32P radiotracers. These gave further evidence indicating that Chaetoceros socialis Lauders and Chlorella sp. were capable of discriminating between phosphate and arsenate ions in seawater. Therefore, it is important to assess the differences in arsenic metabolism by different phyto-plankton species in localized study.