Evaluation of root growth, antioxidant enzyme activity and mineral absorbability of carnation (Dianthus caryophyllus “Express golem”) plantlets cultured in two culture systems supplemented with iron nanoparticles

Abstract

In this study, different concentrations (0, 0.025, 0.05, 0.075, 0.1 and 0.2 mM) of iron nanoparticles (FeNPs) were used to replace 0.1 mM Fe-EDTA in half-strength MS medium to assess their effect on root growth, antioxidant enzyme activity and mineral absorbability of carnation plantlets cultured in in vitro system (MO) and microponic system (MP). The results showed that MP supplemented with 0.075 mM FeNPs was the most optimal culture condition for not only rooting stage, but also antioxidant activities and mineral absorption of carnation. The 3-week-old shoots cultured in this condition obtained the highest growth values with plant height (6.67 cm), root number (9.00 roots/plantlet), average root length (1.80 cm), fresh weight (70.33 mg), dry weight (5.67 mg), dry mass ratio (8.05 %), chlorophyll a (1.96 mg g−1 FW) and chlorophyll b (0.87 mg g−1 FW). Furthermore, the antioxidant activity analysis results showed that the activity of superoxide dismutase (28.52 U g-1 prot), catalase (540.98 U g-1 prot), and ascorbate peroxidase (0.55 U g-1 prot) in plantlets grown in MP system supplemented with 0.075 mM FeNPs were higher than those in MO system (14.15, 426.66 and 0.46 U g-1 prot; respectively) and also in the control (7.84, 309.08, 0.35 U g-1 prot; respectively). In addition, the absorption of potassium (205.51 mg g−1 DW), calcium (27.70 mg g−1 DW), magnesium (25.55 mg g−1 DW) and the iron-uptake rate (79.37 %) were highest in the MP system added with 0.075 mM FeNPs, as compared with those of the others. Plantlets derived from culture in MP system supplemented with FeNPs gave higher survival rate, better growth and development than that of the control treatment (used 0.1 mM Fe-EDTA). The plantlets were investigated after six weeks transplanting into the greenhouse.