Panagiotis Panagopoulos

The cultivation of tolerant species with low-quality irrigation water is one of the main strategies to address the lack of availability of irrigation water. In this work, the effect of salinity on plant growth, nutritional composition, and quality features of Hedypnois cretica and Urospermum picroides was tested. Fresh yield of leaves and roots of both species were severely decreased under high salinity, while the mineral profile of leaves and roots also showed a decrease in most minerals. The recorded values of K/Na and Ca/Na ratios indicate that H. cretica has a higher susceptibility to salt stress due to a higher decrease in the values of the respective ratios compared to U. picroides. Leaf pigments and total phenolic compounds content were not significantly affected by salinity, while total soluble solids and titratable acidity increased under increasing salinity in most cases. Moreover, free proline content increased with increasing salinity, while the opposite trend was recorded for nitrates’ content. In conclusion, our findings indicate that tailor-made nutrient solutions could allow the use of irrigation water of a low quality for the commercial cultivation of H. cretica and U. picroides, thus allowing their domestication and integration in cropping systems where the cultivation of conventional crops is compromised.

Soil salinization is one of the major environmental factors responsible for limited crop production throughout the world. Therefore, there is urgent need to find tolerant/resistant species to exploit in commercial cultivation systems. In this context, the valorization of wild edible greens for human consumption and/or medicinal purposes is gaining more and more interest. The aim of the present work was to study the effect of salinity, e.g., electrical conductivity: 2 mS cm⁻¹ (nutrient solution EC), 6 mS cm⁻¹ and 10 mS cm⁻¹ on plant growth and chemical composition of Reichardia picroides and Taraxacum officinale plants grown in a floating hydroponic system. The results showed that R. picroides is a moderately salt-tolerant species, as the majority of plant growth parameters determined were not negatively affected under the treatment of 6 mS cm⁻¹. On the other hand, the growth parameters of T. officinale plants were severely affected under the same conditions. Moreover, high salinity levels (EC at 10 mS cm⁻¹) impaired the growth of both species. The content of leaves in chlorophylls (a, b and total), carotenoids+xanthophylls and total soluble solids was not significantly affected by the tested EC levels in both species, whereas the titratable acidity increased under the treatment of 10 mS cm⁻¹. Moreover, R. picroides exhibited a more effective adaptation mechanism against saline conditions than T. officinale, as evidenced by the higher accumulation of osmolytes such as proline and the higher shoot K content, probably through a more efficient K/Na selectivity. In conclusion, both species were severely affected by high salinity; however, R. picroides showed promising results regarding its commercial cultivation under moderate salinity levels, especially in regions where resources of high-quality irrigation water are limited.