三角褐指藻对不同形态铁的吸收和利用

Absorption and Utilization of Different Forms of Iron by Phaeodactylum tricornutum

分别向天然海水中添加不同浓度的FeCl_3、铁的乙二胺四乙酸络合物(Fe-EDTA)和铁的去铁胺络合物(FeDFO),对三角褐指藻(Phaeodactylum tricornutum)进行培养,研究其对不同形态铁的吸收和利用.每天测定藻细胞密度及体系液相中和藻细胞内外的铁浓度.结果表明:不同浓度的FeCl3和Fe-EDTA均可促进三角褐指藻生长,不同浓度的Fe-DFO均会抑制其生长.FeCl_3培养体系中,铁主要分布在藻细胞外;Fe-EDTA和Fe-DFO的培养体系中,铁主要存在于液相中.液相铁浓度均随培养时间的增加而减少,细胞内外铁浓度均随培养时间的增加而增加.3种形态铁的三角褐指藻生物可利用性由高到低依次为FeCl_3>Fe-EDTA>Fe-DFO.该结果可为海水中铁的生物可利用性研究提供参考.

To investigate the bioavailability and effect of different iron species on the growth of Phaeodactylum tricornutum, different concentrations of FeCl3, Fe-EDTA and Fe-deferoxamine （Fe-DFO） were added into natural seawater to serve as the iron sources.Cell population and iron concentration in different culture systems were measured every day.The results showed that FeCl3 and Fe-EDTA at all the test concentrations promoted the growth of P. tricornuturn, while Fe-DFO at all concentrations inhibited the growth.When FeCl3 was added to the culture system,iron was mainly distributed on the surface of the algae cells. However, with Fe- EDTA or Fe-DFO in the culture system the iron was mainly in the liquid phase.As the incubation time increased, the concentration of iron in liquid phase decreased,while that of intracellular and extracellutar iron increased.In summary, our results demonstrated that the bioavailability of the three forms of iron to P. tricornutum was in the order of FeCl3〉 Fe-EDTA〉Fe-DFO,which provides references for further study on the bioavailability of iron in the seawater.