Allelopathic potential of weed Neanotis lancifolia (Hook.f.) W.H. Lewis on seed germination and metabolism of mungbean and rice

Abstract

In Laboratory and Field bioassays, the higher concentrations of shoot aqueous extracts of Neanotis lancifolia (Hook. f.) W.H. Lewis proved inhibitory to mungbean and rice. The highest concentration (10 %) of aqueous extract reduced the plumule and radicle length of both test crops. From the N. Lancifolia extracts, 15- allelochemicals (Phenols, alkaloids, flavonoids, flavonols and glycerol) were identified by GC-MS. Of these 5 were major allelochemicals [Oleic acid, Glycidyl oleate, Linoleic acid, Palmitic acid and 18-Nonadecenoic acid]. These compounds at 5 DAS (days after sowing) significantly inhibited the seed germination in mungbean (58.38 %) and rice (57.48 %) at 5 DAS. The inhibitory effects of allelochemicals on seeds germination followed the order: Oleic acid> Glycidyl oleate >Linoleic acid > Palmitic acid > 18-Nonadecenoic acid. The radicle and plumule growth at 11 DAS also followed the same trend. The metabolic changes in both mungbean and rice crops revealed that the aqueous extract reduced the protein, carbohydrates, phenols, tannins and flavonoids contents and the reductions were concentration dependent. We found that the allelopathic potential of N. lancifolia (Hook.f.) W.H. Lewis was due to the presence of 15 inhibitory compounds identified in its extract.