BIOCHEMICAL ALTERATIONS IN WHEAT SEEDLINGS AND SOME WEEDS RELATED TO ALLELOPATHIC POTENTIAL OF SOME MEDICINAL PLANTS

M. A. Balah, H. H. Latif

Abstract: The present study was conducted to investigate the allelopathic effects of some selected medicinal plants (Thymus vulgaris, Salvia officnalis and Calendula officinalis) on seeds germination and seedling total biomass of wheat (Triticum aestivum L.) and their associated weeds, Lolium. multiflorum and Phalaris paradoxa by aqueous extracts at (0, 20, 40, 60 mg DW ml-1) concentrations under laboratory conditions. The extracts of C. officinalis subterranean parts had ED50 values for L. Multiflorum by (20 mg ml-1) root length, P. paradoxa by (15 mg ml-1) dry weight, T. aestivum by (23 mg ml-1) root length. T. vulgaris vegetative extracts had ED50 values for L. multiflorum by (30 mg ml-1) and P. paradoxa by (30.5 mg ml-1) root length. The change in mineral content increase by C. officinalis and T. vulgaris than S. officnalis aqueous extracts as compared with untreated control. The highest reduction in IAA content of T. aestivum seedling achieved from T. vulgaris subterranean parts extract by (81.8 %), ABA and GA content from C. officnalis vegetative extracts by (78.3 and 421%) at concentration 60 mg ml-1 than the untreated control. The addition of C. officnalis and T. vulgaris vegetative extracts at 20 mg ml-1 increased T. aestivum seedlings anthocyanin contents by (21.8 and 20.0%) and total proteins by (23.2 and 28.5)%, respectively, than its control. The highest inhibitory effect achieved from C. officinalis and T. vulgaris vegetative and subterranean parts extract at 40 mg ml-1 reduced tyrosine biosynthesis of T. aestivum seedlings by (92.2, 92.2, 86.2 and 89.6%) respectively compared to the control. The obtained results proposed that C. officinalis and T. vulgaris extracts have herbicidal properties that may provide an alternative to synthetic herbicides for their ability to suppress weed germination and seedling growth in wheat field, but in a limited use especially the highest dose and its prefer to use this extracts in pre emergence stage to prevent weeds emergence and to avoid the adverse effect of allelopathic compounds on wheat seedling and yields.

Keywords: allelopathy; anthocyanin and amino acids; mineral content; phytohormones

Date published: 2019-01-17