Ion uptake of marigold under saline growth conditions

Salinity is one of most significant environmental stresses. Marigold is moderately tolerant to salinity stress. Therefore, in this study, the fresh weights of roots and shoots, root(FW)/shoot(FW) ratio, moisture content of shoots, micronutrient and macronutrient concentrations and ratios of K+/Na+ and Ca2+/Na+ in the roots and shoots of marigold were determined under salinity stress. Five salinity treatments (0, 50, 100, 150, and 200 mM NaCl) were maintained. In the current study, salinity affected the biomass of marigold. An increase of more than 100 mM in salt concentrations significantly reduced the shoot fresh weight. Increasing salinity stress increased the ratios of root(FW)/shoot(FW), which were more significant under high salt levels (150 and 200 mM NaCl). Wet basis moisture contents of the shoots were reduced when salinity stress increased above 100 mM. In this study, salinity stress affected micronutrient and macronutrient uptake. Increases in the salt concentration and decreases in the concentration of Cu2+ and Zn2+ in the roots and Mn2+ and Fe2+ in the shoots were significant. Based on an increase in salinity stress, while the Ca2+, Mg2+, and Na+ concentrations increased, the K+ concentration decreased in the roots and shoots. Moreover, the K+/Na+ and Ca2+/Na+ ratios of the roots and shoots were significantly lower than those of the control in all of the salinity treatments. As a result, under increasing salinity stress, the Ca2+, Mg2+, K+, and Na+ uptakes in marigold were significant, revealing the effects of stress.