Evaluation of Local Micromeria fruticosa and Its Essential Oil Effects on Weed Germination
Asmaa Mohammed Masharqa
اسماء محمد مشارقة
Micromeria fruticosa is an evergreen shrub aromatic plant and endemic to the eastern Mediterranean region including Palestine. There was no information found about the yield of the M. fruticosa aerial parts and its essential oil (EO). In order to evaluate that, 586 plants were grown at Al-arroub station of the National Agriculture Research Center “NARC” in Hebron. Thereafter, plants were harvested eight times within two years. Then after each harvest, the EO was extracted by steam-distillation from the fresh material. The GC-MS analysis was performed on interval hourly samples took during the EO extraction for the August/2018 and October/2018 harvests. Effect of seasonal and extraction time on the EO profile were evaluated. Also, the effect of the EO on weed germination was determined on soil samples infested by common weed species with three different concentrations (0.05, 0.1. and 0.2%). The results shown the average aerial parts production of M. fruticosa for every plant as fresh weight for the seasons of 2017 and 2018, were 0.20 and 0.22 Kg, respectively. The yearly yield of aerial parts for 2017 and 2018 was 680 and 748 Kg/dunam, respectively. Oil density was 0.9459 ± 0.00184 and percentage of average oil production as fresh matter basis was 0.82 and 0.80% for the season 2017 and 2018, respectively. Moreover, the results appeared that the late summer months (August-October) show the highest percentages of the EO extracted from M.fruticosa. A total of 191 compounds were identified in all samples with abundant of the monoterpene pulegone in all with varied proportions. The GC-MC analysis found that the EO got from August and October/2018 harvests reveal high percentages of pulegone (66.22 and 63.75%, respectively), which is the compound that causes inhibition of germination for weeds’ seeds, with 2 hours of extraction. The EO severely affected on the number of germinated weeds. It also observed that the inhibition rate was markedly increased with the increasing of the EO concentration, where the mean of the number of germinated weeds for the concentrations of 0.05, 0.1 and 0.2% was decreased by 24, 27 and 63% respectively compared to the control group P ≤ 0.001. The present study results showed that the EO of M. fruticosa could be used in biocontrol practices, especially in organic farms, as an anti-germination agent.