Identification and Measurement of Some Secondary Metabolites of Stems and Leaves of Euphorbia Heterophylla and Their Allelopathy Effects on Avena Ludoviciana L.

The use of allelopathic materials has been a favorite natural herbicide for plant scientists. The effect of these natural compounds is more than artificial compoundsdue to its water-soluble and halogen-free characteristics. Regarding the increasing resistance of weeds to herbicides, application ofallelopathic method can reduce the use of artificial herbicides and prevent environmental degradation. The purpose of this study was investigation of using Euphorbia heterophylla metabolites in growth and germination control of weed Avena Ludoviciana in farms In order to investigate the allelopathy effects of aqueous and alcohol extracts of (heterophylla Euphorbia), an experiment was conducted at Agricultural Research Center of Golestan (Gorgan city) Province during 2014 and 2015 with a completely randomized design under greenhouse condition on Avena ludoviciana with three replications. The treatments in this experiments were the plant species organs at 2 levels (dry powdered of leaf and stem), solvent type for preparing extracts at 2 levels (water and alcohol(methanol)) and the extract concentrations at 5 levels (0, 25, 50, 75 and 100 percentage).The measured traits included height, leaf wet weight, leaf dry weight, stem wet weight, stem dry weight and leaf area. The aqueous and alcoholic extract of Euphorbiaheterophylla were obtained by dipping of dried material in the special solvents in dark place at room temprature for three days and finally, filtration with muslin cloths. The prepared extracts was stored in 4 degree centigrad refrigerator. This extrat was considered as stock solution and the rest concentrations were preapared from this solution.The extracts sprayed on the target plant (Avenaludoviciana) as post-emergence at 3-4 leaved stages.Total phenolic content was measured using the Folin-Ciocalteu reagent method and the total flavonoid content of the extracts was surveyed by a colorometric method based on aluminum chloride.Finally, the relative recognition of the nature of plant compounds was done by chemical methods and colorimetry.The data were analyzed with SAS, 9.9 software and the means were compared to eache other using LSD (least significant difference) at (p < 0.05) and the graphes was drawn with Excel software. Based on the results of the analysis of variance, except for leaf area of Avena ludoviciana which was affected by the treatments at 95% confidence level (p < 0.05), all the measured traits were significantly affected by the treatments at 99% confidence level (p < 0.01). In general, the results of this study showed that the aqueous extracts of Euphorbia heterophylla stem and leaves had no inhibitory effects on the measured traits at zero levels (control treatment), but the growth and germination of Avena ludoviciana was inhibited by the leaf alcoholic extract and stem aqueous extract at 50 and 100% concentration. These extracts significantly decreased plant height, stem fresh weight, leaf fresh weight and leaf dry weight of Avena ludoviciana. The highest effect was observed on Avena ludoviciana leaf area at 100% concentration of leaf extract and the lowest effect was observed at 75% concentration of stem extract. The results of phytochemical experiments of the aqueous and alcoholic extract of the leaves indicated that the aqueous extract of leaves and stems followed by alcoholic extract of leaves had the highest phenolic compounds and also highest antioxidant properties, respectively. According to the results of this study, it is suggested that, further research must be carried out on the identification and mechanism of action of Euphorbia heterophylla allelopathic compound and their effects on Avena ludoviciana seedlings growth. Thus, it can be used as an alternative source of antioxidant compounds in the organic fertilizer industry. Based on the phytochemical experiments conducted in this study, the existence of secondary metabolites in the Euphorbiaheterophylla extracts was proved. The obtained results from the different extracts (aqueous extract of stem, aqueous extract of leaf, alcoholic extract of stem and alcoholic extract of leaf) showed thatthe alcoholic extracts of leaves significantly affected the growth traits of Avenaludovicianamore than the rest of extracts.It seems that attempting to accurately identify the chemical nature of the allelopathic compounds present in different organs of Euphorbiaheterophyllaand the factors that affecting these compounds can lead to the other studies based on biological weed management.