Domestication of Wild Edible Species: The Response of Scolymus hispanicus Plants to Different Fertigation Regimes

Scolymus hispanicus L. is a wild edible species with wide distribution in the Mediterranean area. Recent research has focused on the domestication of wild edible greens, which is essential for the preservation of agroecosystems and the increase in biodiversity, especially under the adversely changing climate conditions. In the present work, the aim was to evaluate the response of S. hispanicus plants to different fertilization regimes that varied in the amounts of nitrogen, phosphorus and potassium in regard to plant growth and chemical composition of leaves. For this purpose, plants were grown in pots within an unheated greenhouse. Seven experimental treatments were used, including six fertigation regimes (SH1-SH6) and the control treatment (SHC), where no fertilizers were added. Fresh yield was beneficially affected by the treatments that included a high content of P and K (e.g., SH3 and SH5), while lesser amounts of these macronutrients (e.g., SH1 and SH4) resulted in higher chlorophyll content (SPAD index) and leaf area. In terms of mineral profile, high amounts of P and K improved dietary fiber and carbohydrates content, whereas the untreated plants had the highest content of ash, fat and crude protein. Oxalic and quinic acid were the major organic acids detected, with fertigation regimes significantly reducing their content compared to the control treatment. alpha-tocopherol was the only isoform of vitamin E detected in all the samples, while glucose and fructose were the most abundant sugars, with their highest content detected in control and SH4 treatments, respectively. Scolymus hispanicus leaves were rich in macro and micro minerals, while their contents varied depending on the fertigation regime. Finally, alpha-linolenic, palmitic, and linoleic acid were the major fatty acids detected, while their contents were beneficially affected by low nutrient inputs (e.g., untreated plants and SH1 and SH2 treatments). In conclusion, the regulation of nutrient solution seems to be an effective practice to increase fresh yield in S. hispanicus without compromising the nutritional profile of the edible product, while low inputs of macronutrients such as P and K may improve the chemical composition of the species, especially in terms of n-fatty acids.