Effect of Iron on cell division and intracellular beta-carotene and chlorophyll synthesis in unicellular green alga Dunaliella

the aim of this study was to investigate the effect of iron on cell division، interacellular beta-carotene and chlorophyll synthesis in unicellular green alga Dunaliella. In this study 4، 32، 64، 128، 256 and 512µM concentrations of iron was applied on D. bardawil and D. salina. The culture media were kept in a growth chamber in a light/ dark regime of 16/8 hours at 26±2 °C. Then beta-carotene، chlorophyll content and cell divisions were determined. In both species the maximum cell growth was observed in 4 µM and the amount of chlorophyll as well as cell growth decreased by the increase of iron concentration in the medium. The maximum reduction of the chlorophyll and cell growth was observed in 512 µM، where as the maximum intracellular beta-carotene content was shown in 128 µM. Results showed that probably free radicals contents of both species have been increased in presence of iron. Iron treatment decreased the chlorophyll content to reduce the free radicals produced due to excitation of chlorophyll molecules. Moreover، the cells produced high amount of beta-carotene as an antioxidant against free radicals in presence of Iron. It seems D. salina has better performance in presence of high concentration of iron than D. bardawil due to less synthesis of beta-carotene and more production of other antioxidants as well as reduction of chlorophyll production.