Fe nutrition demand and utilization by the green alga Dunaliella bardawil

The Fe nutritional demands, requirements and mechanisms of uptake by Dunali ella bardawil as well as potential Fe sources were studied. A comparison be tween Fe uptake from bacterial siderophores and from synthetic ferric chela tes revealed algal growth response and chlorophyll synthesis to increasing concentrations and availability at a range of 0.01 mu M-5 mu M, as well as differences in efficiency. Furthermore, chloroplast ultrastructure, as obse rved by TEM, was affected by Fe deficiency, as was chlorophyll content. Fer ric reduction is involved in the Fe uptake mechanism of Fe-stressed D. bard awil. Nutrient solution with controlled levels of free Fe2+ as well as spec trophotometric assays were used to measure Fe3+ reduction. This study shows that D. bardawil utilizes Fe3+ via a reduction mechanism, similar to that of strategy-I higher plants.