Ecological and Physiological Studies on Some Medicinal plants

Concerning the biological activities, the methanolic extract of Nicotiana glauca showed the highest antioxidant activity, while the extract of Calligomum polygnoidessubsp. comosum exhibited the weakest antioxidant activity. While the methanolic extract of Pulicaria undulatAsubsp.undulata showed the highest antimicrobial activity, followed by the extracts of Hyoscyamus muticus , Nicotiana glauca and finally by Calligomum polygnoidessubsp. comosum. On the other hand, the aqueous extract of Nicotiana glauca showed the highest inhibition precentages of seed germination, radical growth and plumale growth of summer weed Portulaca oleracea, followed by the extracts of Pulicaria undulata subsp.undulata , Hyoscyamus muticus and finally by Calligomum polygnoidessubsp. comosum. Therefore, it can be concluded that, the selected plant species in the present study are obviously considered as tolerant species against extreme drought and salinity. These species could be also used as natural renewable resources in numerous beneficial purposes such as medicine industry, natural antioxidants, antimicrobial agents and allelopathic potential for biological control of weeds.