Golden thistle (Scolymus hispanicus L.) is a wild edible green of high nutritional value, used in the traditional Mediterranean diet. Nowadays, there is an increasing demand from consumers for golden thistle and concomitantly an increasing interest in integrating it into modern cultivation systems. Soilless culture is a promising cultivation option that can maximize yield and quality of golden thistle. The aim of this study was to examine the combined effect of electrical conductivity (EC) and nitrogen (N) supply level on growth and nutritional quality of golden thistle grown on a substrate in a soilless cropping system. The two experimental factors were examined in a 2-factorial experiment with two EC levels, a low (2.2 dS m⁻¹) and high (2.8 dS m⁻¹), combined with two total-N (NO₃⁻ + NH₄⁺) supply levels, low (13.30 mmol L⁻¹) and high (17.30 mmoL L⁻¹), in the supplied nutrient solution. Root fresh and dry weight (commercial yield) were unaffected by treatments; however, high EC significantly reduced shoot fresh and dry biomass by 21 and 28% compared to low EC. High EC increased K⁺ concentrations in shoots and roots but decreased shoot Ca²⁺ level. Nitrate concentration in the drainage solution and plant tissues was primarily driven by N supply, with high N increasing leaf NO₃⁻ by up to 45% without surpassing the regulatory safety limit. Water productivity did not differ among treatments, but low EC improved agronomic efficiency of K⁺, Ca²⁺, Mg²⁺, and S, while low N enhanced N agronomic efficiency by 44%. Overall, low EC promoted vegetative growth and nutrient use efficiency, while increasing N above 13.3 mmol L⁻¹ offered no yield benefit and raised tissue nitrate levels. For optimal yield and quality, a nutrient solution with low EC and N supply is recommended for the soilless cultivation of golden thistle.

The aim of this work was to study maize root phenotype under sulfur deficiency stress towards revealing potential correlations between the altered phenotypic traits and the corresponding dry mass, sulfur, and iron allocation within plants at the whole-plant level. The dynamics of root morphological and anatomical traits were monitored. These traits were then correlated with plant foliage traits along with dry mass and sulfur and iron allocation dynamics in the shoot versus root. Plants grown under sulfate deprivation did not seem to invest in new root axes. Crown roots presented anatomical differences in all parameters studied; e.g., more and larger xylem vessels in order to maximize water and nutrient transport in the xylem sap. In the root system of S-deficient plants, a reduced concentration of sulfur was observed, whilst organic sulfur predominated over sulfates. A reduction in total iron concentration was monitored, and differences in its subcellular localization were observed. As expected, S-deprivation negatively affected the total sulfur concentration in the aerial plant part, as well as greatly impacted iron allocation in the foliage. Phenotypic adaptation to sulfur deprivation in maize presented alterations mainly in the root anatomy; towards competent handling of the initial sulfur and the induced iron deficiencies.