The response of Amaranthaceae halophytes to various hydroponic solution salinities

Interest in the ecological and nutritional significance of halophytes has led researchers to explore their cultivation under different salinity levels. To assess the potential and adaptive strategies of halophytes in the Amaranthaceae family, hydroponic cultivation provides an effective method for growing these plants as alternative crops in a controlled environment. This study aimed to examine the effect of hydroponic solution salinity (0, 150, and 300 mM NaCl) on the growth responses of three Amaranthaceae halophytes, including A. lividus, A. passion, and A. red Aztec, and their suitability for cultivation in controlled environments. The environmental conditions, Blue/Red/Far-Red LED spectrum at 22:65:13, an intensity of 250 µmol m^-²s^-¹, and a temperature of 18/22±2°C, were maintained in a walk-in growth chamber throughout the experiment. A strong negative correlation between hydroponic solution salinity and survival rate, height, fresh weight, root length, leaf area, and antioxidant activity in all tested Amaranthaceae species was detected, except for a strong positive correlation between salinity and total phenolic compounds in A. passion. Based on survival rate, shoot and root biomass, and an antioxidant assay, the hydroponic solution salinity of 150 mM NaCl seems to be the salt tolerance level for the tested Amaranthaceae halophytes. However, further investigations of osmotically active metabolites, specific proteins, and scavenging of oxygen radicals under salt stress conditions are needed.