Does Fe accumulation in durum wheat seeds benefit from improved whole-plant sulfur nutrition?

Sulphur (S) and iron (Fe) are an essential macro- and micronutrients for plant growth and development. A balanced supply of S and Fe for plants is of major importance since it has been demonstrated that plant capability to take up and accumulate Fe is strongly dependent on S availability in the growth medium and vice versa. In fact, that Fe deficiency adaptation requires the adjustment of S uptake and assimilation rate. Furthermore, it has been demonstrated that providing S above adequate concentrations may result in the improvement of Fe use efficiency in wheat plants and this S nutritional effect seems to be especially advantageous for plants grown under severe Fe limitation. Aim of this study was to evaluate whether and to what extent the changes in S nutrition affect Fe accumulation into grains and whether grain Fe concentrations are significantly correlated with the concentration of Fe in the vegetative tissue. This approach might represent an important tool to realize the improvement of the nutritional value of food crops by increasing Fe content (agronomic biofortification) through soil and crop management strategies which allow to may prevent Fe deficiency in crops without additional input of Fe fertilizers. Durum wheat plants were grown on sand/perlite mixture with sufficient (1.2 mM) and high (2.5 mM) S supplies and with 10 or 80 M Fe-EDTA during the life cycle. In particular, we will discuss the effect of S supply on plant growth parameters (fresh and dry weight and chlorophyll content) and on total S accumulation rate at both leaf and seed level. In addition, the relative changes of the leaf and seed ionome induced by different nutritional conditions were evaluated by using inductively coupled plasma-optical emission spectroscopy (ICP-OES). Finally, whole seeds and seed sections were subjected toinvestigated with micro-focused X-ray fluorescence (XRF) imaging to clarify the elemental distribution maps.of several elements, including S and Fe. Significant differences in the concentration and distribution of a number of elements could be observed according to the different treatments.