Irradiated sodium alginate improves plant growth, physiological activities and active constituents in Mentha arvensis L

Sodium alginate, irradiated by Co-60 gamma rays in solid state, elicits plant growth promoting responses in various plants. Irradiated sodium alginate (ISA) was applied as a foliar spray on mint (Mentha arvensis L.) to investigate its effect on plant growth, physiological attributes and herbage yield as well as on content and yield of essential oil and its components (menthol, L-menthone, isomenthone and methyl acetate). A simple pot experiment was conducted applying five concentrations of ISA, viz. 25, 50, 75, 100 and 125 mg L, as foliar sprays. GPC study revealed formation of lower molecular weight oligomer fractions in irradiated samples which could be responsible for plant growth promotion in the present work. Of the five ISA concentrations, 100 mg L proved the best. As compared to the control, the ISA applied at 100 mg L resulted in the highest values of all physiological parameters at 100 and 120 days after planting.