Assessing the salinity effects on mineral composition and nutritional quality of green and red ‘Baby’ lettuce

Abstract

The work focuses on the responses of two baby lettuce (Lactuca sativa L.) cultivars (green “P aris I sland” and red “S anguine”) to different NaCl solutions (0, 5, 10 and 20 mM). Plant mineral composition (N, P, K, Ca, Mg, Fe, Mn, Zn, Cu, B, C l and Na) and nutritional quality (nitrates, ascorbic acid, phenolics, flavonoids and antioxidant activity) were determined. Salinity was found to be able to reduce the concentration of K; while, it was able to enhance Zn and Cu concentrations in baby leaves of both cultivars. Salinity was even able to decrease Ca concentration in green lettuce, and to increase the concentrations of Fe, Mn and B in red lettuce. Moreover, salinity was connected to the accumulation of Cl and Na in baby leaves. However, the use of saline waters enhanced health‐beneficial phenolic compounds in baby leaves in some instances. Practical Applications: In recent years, baby vegetables are becoming more and more popular as they are easy to prepare for the market (fast food, ready‐to‐eat salads), with a low degree of injury, as in the case of fresh‐cut vegetables. Salinity is one of the most important factors limiting yield of several horticultural crops worldwide. Although lettuce is considered moderately sensitive to salinity, literature reveals that salinity is connected with biosynthesis of nutritional compounds. The present study may serve as a tool to better understand baby lettuce mineral nutrition and the consequent management of fertilizers, which is of value in the baby vegetable production industry and is critical in improving yield and quality. In addition, enhancement of phenolic compounds, induced by salinity in some instances, may be of importance in a diet rich in antioxidants.