Allelopathic Effects of Oldeania alpina (K. Schum.) Leaves Aqueous Extract on Seed Germination and Initial Seedling Growth of two selected crops

Abstract This study aimed to investigate the allelopathic effects of Oldeania alpina leaves aqueous extract on germination and initial growth of barley (Hordeum vulgare L.) and wheat (Triticum aestivum L.) test crops in a laboratory experiment. To this end, different aqueous extract concentrations (0%, 2.5%, 5%, 7.5%, and 10%) were prepared and used to irrigate seeds of test crops. The effect of the extract was tested by placing a set of 50 seeds of barley and wheat separately in six replicates of Petri dishes using a completely randomized design. Besides, four different solvents (hexane, ethyl acetate, methanol, and water) were used to prepare O. alpina leaves extracts and subjected to qualitative analysis of nine selected allelochemical compounds namely; flavonoids, phenols, tannins, terpenoids, steroids, quinones, coumarins, saponin and, anthraquinones. Data were analyzed using both descriptive and inferential statistics by SPSS software version 27. The study results showed a significant (p < 0.05) concentrations-based inhibitory effect of O. alpina leaves extract on germination parameters and initial growth of the two tested crops. In addition, it showed the presence of all tested allelochemicals except Anthraquinones in O. alpina leaves extracts. However, further field study would be necessary to evaluate and confirm the findings on a natural soil condition.