Variation of polyphenolic composition, antioxidants and physiological characteristics of dill (Anethum graveolens L.) as affected by bicarbonate-induced iron deficiency conditions

This study aimed to investigate the effects of bicarbonate-induced iron deficiency on growth, photosynthetic performance, secondary metabolite content, and related antioxidant capacity in seedlings of Anethum graveolens (L.) grown under controlled conditions in the presence of iron (+Fe) or in induced-iron deficient (+Fe + Bic) media. The main results have shown that dill shoot and plant biomass production significantly decreased under Fe deficiency conditions, whereas that of roots was not affected by such constraint. Moreover, Fe deficiency resulted in a significant reduction of chlorophyll and Fe concentration. Interestingly, when grown under Fe deficiency conditions, A. graveolens was able to increase its shoot iron use efficiency (FeUE). In addition, levels of individual and of total phenolic compounds were shown to be raised in roots as well in leaves. This fact was accompanied by an increased antioxidant activity, as measured through distinct in vitro methods (ABTS(center dot+), O-2(center dot-), HO center dot, FRAP and ORAC). The overall data suggests that A. graveolens was able to maintain plant growth and to preserve adequate chlorophyll synthesis under iron-limiting conditions, probably due to its better Fe-use efficiency. The species was also able to modulate secondary metabolites metabolism and its antioxidant capacity, in order to minimize the deleterious effects of reactive oxygen species.