Allelopathic effect of Euphorbia guyoniana aqueous extract and their potential uses as natural herbicides

The aim of the present study was to investigate the potential allelopathic effects of Euphorbia guyoniana (donor species) aqueous extract on germination efficiency of two weeds (Bromus tectorum and Melilotus indica) and one crop species (Triticum aestivum) under laboratory conditions. The germination efficiency, plumule and radicle length of Bromus was completely inhibited at the highest concentration of aqueous extracts of the donor species level (10%). The two recipient species exerted weak measures as affected by the highest concentration level of the donor. This inhibition was markedly obvious in B. tectorum than in M. indica indicating that B. tectorum is more sensitive to the tested donor, while the M. indica is more adapted to the aqueous extract than the B. tectorum

Assessment of natural radioactivity levels and radiation hazard indices for soil samples from Abha, Saudi Arabia

The natural level of radioactivity in the soil is one of the main causes of external gamma exposure. It was considered necessary to measure concentrations of gamma ray activity due to naturally occurring, potentially hazardous radionuclides from, 226Ra, 232Th and 40K for soil samples collected from different locations (Abha, Khamis Mushait and Muhail Asir) in Asir region. The samples were analyzed for its naturally occurring radionuclides by gamma-ray spectrometry using NaI (Tl). The results show that the average values of activity for 226Ra, 232Th and 40K in range of 38.2 ± 0.1–44.1 ± 0.1, 23.49 ± 0.20–41.9 ± 0.2 and from 182.5 ± 1.0 to 251.5 ± 1.3 Bq Kg−1 respectively. Also the frequency distribution for all radioactive variables in soil was analyzed. Additionally evaluations have been made of the radiological hazards and it's diagramed by Surfer program in maps. These data will serve as the baseline level of radionuclides that occur naturally in the study area and will be useful for tracking and assessing any pollution inventory in the environment of this region. Keywords: Frequency distribution, Server 7, Abha, Khamis Mushait, Muhail Asi