Effect of NaCl concentration on the growth and phytochemicals of hydroponically grown Limonium tetragonum in a vertical farm

Abstract

Limonium (L.) tetragonum is a halophyte that has a tolerance to salt and is all over the southwest coast of Korea. The halophytes will be potential materials for a medicinal crop because it has various enzymatic and non-enzymatic components. This experiment was conducted to determine the effect of sodium chloride (NaCl) on growth and metabolome in L. tetragonum in the vertical farm. Germinated seeds were transplanted in a deep flow technique system using a hoagland nutrient solution (HNS; pH 6.5, EC 1.1 dS cm-1) for 1 week. After then, NaCl concentrations of HNS were set at 0 (Control), 50, 100, 200, and 400 mM. The environmental conditions were maintained at a temperature of 25±3°C, relative humidity of 70±10%, and 160±10 μmol m-2s-1(photosynthetic photon flux density; PPFD, white LED, 12h photoperiod). As a result, the shoot of fresh weight, the number of leaves, and the leaf area were reduced at a concentration of 100 mM or higher. The chlorophyll fluorescence (Fv/Fm) of the NaCl treatments showed no difference except that it was decreased at 100 mM, indicating that the L. tetragonum has resistance to the saline environment. As a result of analysis by LC-MS HPLC, myricetin-3-O-β-D-galactoside and 5,7,2',5'-tetrahydroxy flavanone-3-O-β-D-galactoside contents were increased compared to the control. Myricitrin has stronger antioxidant activity, content was at least 1.6 times higher at 50, 100, and 200 mM compared to the control. Flavanone is a class of flavonoids and was highest at 50, 200, and 400 mM. Flavanone showed contents that were at least 3.8 times higher than that of the control, showing an increase compared to the control in all NaCl treatments. In conclusion, the lower the NaCl concentration, the better the growth, but the production of substances increases in the NaCl environment, suggesting the need for NaCl for the production of L. tetragonum. © 2023 International Society for Horticultural Science. All rights reserved.