Fullerenol affects maize plants depending on their iron status

Abstract

Although fullerene (C60) has attracted great interest as a carbon-based nanomaterial with unique properties, today, little is known about the interaction of its water-soluble derivates, including fullerenol with higher plants. Here, we investigated how fullerenol [C60(OH)22-24] affects Zea mays, as a Strategy II plant, depending on its iron status. Iron deficiency chlorosis is a common nutritional disorder affecting plants. Maize plants were grown hydroponically, either with [+FeII (ferrous) or +FeIII (ferric)] or in Fe-free (-FeII and -FeIII) nutrient solution and with or without a fullerenol supply. Fullerenol affected plants differently depending on their Fe status. The beneficial effects of fullerenol were observed in the FeII-deprived plants, including successful suppression of plant Fe-deficiency chlorosis mainly in the younger (basal and middle) region of the leaf blade. This region expressed more severe chlorosis as compared with the older (apical) region of the leaf blade. These changes were accompanied by a significant increase in leaf active Fe and lowering the root apoplastic Fe, suggesting that fullerenol may enhance Fe mobilization in the roots, helping to alleviate Fe deficiency chlorosis. By contrast, there were no observable effects in the FeIII-deprived plants being significantly lower in the root apoplastic Fe as compared with the FeII-deficient plants. Additionally, fullerenol did not affect the Fe-sufficient plants, irrespective of the Fe species (FeIII-EDTA or FeII-EDTA) used as Fe-sources. Our results provide new evidence for the beneficial role of Fe-fullerenol interactions in the enhancement of gramineous plant tolerance to Fe deficiency conditions, which are one of the major limiting factors for crop production all over the world.