Physiological and biochemical responses of Limonium tetragonum to NaCl concentrations in hydroponic solution.

The increase in the NaCl concentration resulted in the decrease in the water potential of the leaves. The Na content accumulated in the aerial part increased rapidly and the content of K, which acts as an antagonist, decreased with the increase in NaCl concentrations in hydroponics. The total amino acid content of decreased compared to the 0-mM NaCl, and most of the amino acid content decreased as the NaCl concentration increased. In contrast, the content of urea, proline (Pro), β-alanine, ornithine, and arginine was increased with an increase in NaCl concentration. The Pro content at 100-mM NaCl accounted for 60% of the total amino acids and was found to be a major osmoregulator as an important component of the salt defense mechanisms. The top five compounds identified in the were classified as flavonoids while the flavanone compound was detected only in the NaCl treatments. A total of four myricetin glycosides were increased in comparison to the 0-mM NaCl. Among the differentially expressed genes, a significantly large change in Gene ontology was seen in the circadian rhythm. NaCl treatment enhanced the flavonoid-based substances of . The optimum NaCl concentration for the enhancement of secondary metabolites of the in the vertical farm-hydroponic cultivation system was 75-mM NaCl.