Pogostemon benghalensis essential oil inhibited the weed growth via causing oxidative damage

Abstract

The present study was conducted to evaluate the phytotoxic potential of Pogostemon oil in terms of oxidative stress on two weeds, viz. Avena fatua L. and Phalaris minor Retz. GC–MS analysis revealed that Pogostemon oil is rich in sesquiterpenes with azulen-2-ol, 1,4-dimethyl-7-(1-methyl ethyl)-as the major component of the oil with maximum % area (28.2%). For the laboratory bioassay, oil emulsion of different concentrations, ranging from 0.25 to 2.5 mg mL−1, was prepared. The effect of oil treatment was studied on per cent germination, seedling length, chlorophyll content and dry weight of the test plants. The inhibitory effect of Pogostemon oil was much pronounced on Avena fatua as compared to Phalaris minor. Roots were adversely affected due to oxidative damage. Consequently, oxidative damage, IC30, IC50 and IC70 values for A. fatua were calculated. Pogostemon oil treatment induced excessive generation of ROS leading to oxidative stress in test plant. ROS further disintegrated membrane integrity as evident from the increased level of MDA, REL and decreased level of CDs. Further exposure to Pogostemon oil enhanced the activities of antioxidant enzymes, thus indicating the activation of ROS scavenging mechanism. Thus, Pogostemon oil inhibits the growth of test plant via inducing oxidative stress and therefore shows potential towards weed management.