Stimulation of Growth of Peppermint (Mentha piperita) by Phosfon, a Growth Retardant

Abstract The shoot growth and fresh weight of Mentha piperita grown in soil were stimulated at concentrations of 1.26 × 10 −5 M to 7.77 × 10 −4 M phosfon (2,4‐dichlorobenzyl tributyl phosphonium chloride) while higher concentrations resulted in retardation of growth. Concentrations of 6.30 × 10 −7 M to 3.78 × 10 −5 M caused retardation of growth in mineral nutrient solution, and even death at the highest concentrations. However, when the M. piperita plants were grown in mineral nutrient solutions at concentrations of phosfon which had been sequentially lowered from 2.52 × 10 −8 M to 2.52 × 10 −12 M , the shoot growth and fresh weight were stimulated as in the case of plants grown in phosfon treated soil.