Collection of plant materials
Donor species (O. vaginalis) has been collected during the vegetative and flowering stages at summer from sand dunes habitat in the northwest of Egypt in Matruh governorate. The plant materials were air dried then ground. Seeds of the crop species (V. faba) were purchased from the International Research Center, El-Dokki, Giza, Egypt. Healthy uniform seeds of R. dentatus were collected from broad bean fields at El-Bihara province during June 2021. The formal identification of the plant materials was identified by Prof. Dr. Salama El-Darier, and confirmed by Herbarium of Faculty of science, Alexandria University.
Preparation of donor species aqueous extracts
Stock aqueous extracts and subsequent dilutions were obtained by extracting 100 g of dried powder of donor species with 1000 ml distilled water. this would be full strength concentration (100%). The extracts were prepared no more than 48 h in advance and were kept in a refrigerator at 5oC until used and the purified extract was adjusted to pH 6.8 with 1M HCl. Under such an optimal pH, no significant growth inhibition occurs (Macias et al., 2000; Singh et al., 2003). Subsequent series of dilutions were prepared from the stock solutions (5, 10, 20 and 40% besides the control) (Hemada and El-Darier, 2015).
General Phytochemical Screening of the Donor Species
Qualitative phytochemical screening to determine sterols or terpenes (Harborne, 1998), carbohydrates or glycosides (Lewis and Smith, 1967), tannins (Harborne, 1998), flavonoids (Harborne, 1998), saponins (Farnsworth, 1966), alkaloids (Harborne, 1999) and High-performance liquid chromatography was performed by using the analytical HPLC system by (Boligon and Athayde, 2014).
Germination bioassay
Petri-dish experiment was applied to investigate the biological activity of O. vaginalis shoot aqueous extract (OVSAE) on germination percentage (GP), plumule (PL) and radicle (RL) lengths of both crop and weed species. To accomplish this experiment, ten seeds of each of the weed and crop species were arranged in 9-cm diameter Petri-dishes lined with two discs of Whatman No.1 filter paper under normal laboratory conditions with day temperature ranging from 22-27oC and night temperature from 14-18oC. Fifteen ml of the respective donor species aqueous extracts (5, 10, 20 and 40%) or distilled water as control were added daily to 3 replicates in a randomized complete block design. Before sowing, the seeds of the two-recipient species were immersed in 2% CHLOREX for 2 minutes then rinsed four times with distilled water (El-Kenany et al., 2017).
Inhibition percentage (IP) of the donor species extracts were expressed as a percentage of growth (germination) of the test species in different concentration levels with respect to water control. using formula described by Sundra and Pote (1978). IP%= 100 – (E2×100/E1) Where, IP = % inhibition. E1 = Response of control plant. E2 = Response of treatment plant
Growth bioassay
Pot experiment was performed to test the effect of different levels (1, 2, 5 and 10 %) of O. vaginalis shoot crude powder (OVSCP) on some growth parameters [(seedling shoot and root lengths (cm), seedling fresh and dry weights (g)], physiological parameters (total proteins, carbohydrates, phenolics and flavonoids) of crop species as well as weed species was also expert.
Ten seeds of the two-recipient species were sown in plastic pots (16 cm in diameter and 15 cm height) with about 1000 g of clay loam soil. Treatments were arranged in a completely randomized block design with three replicates. The plants were watered every two days on the average with filtered tap water. The amount of water corresponding to average soil–plant evapotranspiration calculated from weight loss over a 24 h interval. The experiment was performed under normal laboratory conditions (22±2°C temperature, 75±2% relative humidity, and 12/10 h light/dark photoperiod). After 21 days, the homogenous seedlings were harvested (El-Kenany et al., 2017).
Determination of some physiological parameters
Extraction and estimation of total available carbohydrates (TAC) described by Murata et al. (1968). Total protein fraction was extracted by adding 10 ml of 0.5 N NaOH to about 100mg of the oven-dry plant material which was left over night. The extract was completed to volume with distilled water (Rausch, 1981). Estimation of total protein was done as the method described by Hartree (1972). Also, Preparation of methanolic extract to Determine total phenolics described by Demiray et al. (2009) and flavonoids by Krishna et al. (2010)
Statistical analysis
The data was subjected to a one-way analysis of variance (Zar, 1984). Pairwise comparisons of means were performed using least significant differences (LSD) at probability 0.05. figures illustrated using Tukey’s test at 5% of probability