Effect of Structurally Different Plant Growth Regulators (PGRs) on the Concentration, Yield, and Constituents of Peppermint Essential Oil

Abstract

ABSTRACTA study was designed to study the effect of structurally different plant growth regulators (PGRs) and to establish the most potent PGR(s) for maximizing the yield and quality attributes of peppermint (Mentha piperita) oil. The foliage was sprayed with 5 × 10−6 M of 6-benzylaminopurine (BAP), chloromequat (CCC), gibberellic acid (GA3), indole-3-acetic acid (IAA), and indole-3-butyric acid (IBA), kinetin (Kn), methyl jasmonate (MJ), salicylic acid (SA), and triacontanol (Tria) at 60 d after transplant (DAT). Concentration, yield, and active constituents of M. piperita oil were studied at 90 DAT. The data showed varied effects of the PGRs on parameters studied. SA proved to be the best for increasing oil content, oil yield, menthol concentration, and menthol yield in M. piperita. However, BAP proved to be the best for menthone content; GA3, for menthyl acetate content; Tria, for menthone yield; and SA, for menthyl acetate yield. The effect in terms of the menthol content was SA > GA3 > IBA > IAA > Kn > Tria > MJ > BAP > CCC.