Fe nutrition demand and utilization by the green alga Dunaliella bardawil

The Fe nutritional demands, requirements and mechanisms of uptake by Dunaliella bardawil as well as potential Fe sources were studied. A comparison between Fe uptake from bacterial siderophores and from synthetic ferric chelates revealed algal growth response and chlorophyll synthesis to increasing concentrations and availability at a range of 0.01 μM-5 μM, as well as differences in efficiency. Furthermore, chloroplast ultrastructure, as observed by TEM, was affected by Fe deficiency, as was chlorophyll content. Ferric reduction is involved in the Fe uptake mechanism of Fe-stressed D. bardawil. Nutrient solution with controlled levels of free Fe²⁺ as well as spectrophotometric 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.