Selenium biofortification and grafting modulate plant performance and functional features of cherry tomato grown in a soilless system

Selenium (Se) is an essential trace element for humans due to its importance in a number of enzymes. Vegetable grafting is a valuable tool to overcome biotic and/or abiotic issues and to increase vigour, yield traits and fruit quality. The present work aimed at testing both different Se concentrations (0.0, 1.0, 2.0 and 4.0 μmol Se L−1) supplied via fertigation and grafting on cherry tomato in soilless culture. Se at 2.0 μmol L−1 improved total fruit yield by 60.0 % and 31.4 % in ungrafted and grafted plants, respectively as compared to the control. Marketable yield was positively affected by Se-biofortification and grafting. Se at 2.0 μmol L−1 improved N use efficiency by 60.3 % and 31.5 % in ungrafted and grafted plants, respectively. Furthermore, Se at 4.0 μmol L−1 and grafting enhanced fruit firmness, SSC, polyphenol content and total carotenoids. Ascorbic acid and lycopene were enhanced by Se-doses and grafting. Fruit Se concentration in ungrafted plants varied from 0.1 mg kg−1 of dry weight (DW) in the control to 8.9 mg kg−1 DW in plants treated with 4.0 μmol Se L−1. Se fruits concentration in grafted plants ranged from 0.08 in the control to 9.8 mg kg−1 DW in plants treated at 4.0 μmol L−1. Non-grafted and grafted plants manifested an increment in the hazard quotient (HQgv) in reaction to Se. HQgv fluctuated from 0.002 to 0.353, with a daily intake for Se below the recommended value. Finally, Se-biofortification (at 2.0 or 4.0 μmol L−1) and grafting succeeded in improving tomato plant performance, nutritional and health-promoting compounds.