The present study investigated the allelopathic effects of various black mustard ( Brassica nigra L.) plant parts on alfalfa germination and seedling growth. Aqueous extracts of black mustard ( Brassica nigra L.) leaf, stem, flower and root plant parts were made to determine their effects on germination and dry weights of hypocotyl, and radicle length of 5-day-old alfalfa seedlings over a range of extract concentrations. All aqueous extracts significantly inhibited alfalfa seed germination and seedling growth when compared with the distilled water control. Increasing the aqueous extract concentrations of separated Brassica nigra plant parts significantly inhibited alfalfa germination, seedling length and weight. Based on significant radicle length reactions to aqueous extracts, the toxicity may be classified in the following order of decreasing inhibition: flower, leaf, mixture of all plant parts, root, and stem. Increasing the concentration of aqueous flower extracts significantly inhibited the water uptake by germinated alfalfa seeds. The greatest inhibition in water uptake occurred at a 12 g kg -1 extract concentration for seeds soaked for 8 h.

Growth and micronutrient acquisition of some apple (Malus dometsica Borkh) varieties (Galla, MM 111, MM I06, M 26, and M6 York) were studied under gradually in vitro induced NaCl (from 0, 50 to 100 mM) salinity. Microshoot dry weight tended to increase with increasing salinity level in all varieties except in M 26 and M6 York as some decline was obtained at 100 mM NaCl. Shoot proliferation was decreased significantly in Galla at 100 mM NaCl and at both salinity levels in M 26 compared to the control (0 mM). A significant decrease in shoot zinc (Zn) acquisition with increasing salinity level was obtained in all varieties except MM 111. M6 York and MM 111 decreased their copper (Cu) acquisition significantly at 50 mM NaCl and then increased at 100 mM salinity level. Meanwhile, a significant decrease in Cu acquisition with increasing NaCl concentration was obtained in Galla and M 26. Galla, MM 106, and M 26 showed a significant increase in manganese (Mn) acquisition at 50 mM NaCl followed by a decrease at 100 mM salinity level. On the other hand, Mn acquisition continued to decrease significantly in MM 111 while M6 York increased its Mn acquisition with increasing salinity. M 1209 SHIBLIETAL. 111 and M6 York showed a significant decrease in iron (Fe) acquisition at 50 mMNaCl followed by an increase at 100mM NaCl. Galla and M 26 continued to decrease Fe acquisition with elevated salinity level, whereas Fe in MM 106 increased with salinity.

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Paronchia argentea is traditionally being used for medicinal purposes in Jordan. The current investigation was designed to check the in vitro efficacy of in vitro and ex vitro P. argentea against selected bacterial and fungal strains. The antimicrobial properties of in vitro plantlets and field (ex vitro) plant extracts of P. argentea were investigated against both bacteria and fungi, after and before heavy metals stress used. In this study, four bacterial species were used: Listeria monocytogen and Staphylococcus aureus (Gram positive bacteria) Salmonella typhimurum and Coronobacter sakazakii (Gram negative bacteria) and Calvularia lunata as a mold. The obtained results revealed that the in vitro grown plantlets with the supplemented of lead (Pb), copper (Cu) or Cobalt (Co) with methanol and aqueous extract showed significant inhibitory activities within zones of inhibition ranging between 6.7-30.0 mm. All extracts of P. argentea had activity against the fungi and bacteria tested. The maximum inhibition zone was found in Staphylococcus aureus (30 mm inhibition zone) in medium supplemented with 0.3 mg/L Cu followed by Calvularia lunata (30.0 mm inhibition zone). The methanolic and aqueous P. argentea extract indicate that the solvent plays an important role in the solubility of the antimicrobial substance and also affects the activity of the microbe. Both field (ex vitro) and tissue culture plant extract showed similar antimicrobial activity. The present study could be used as an approach for the development of new, alternative and cheap antimicrobial drugs, particularly against the infections caused by the tested microbes through the tissue culture technology.

<p class="042abstractstekst"><em>Tetragonolobus palaestinus</em> Bioss (Aljalaton) is one of the Jordanian medicinal plants that can be used to treat stomach pain and some infections. This study was done in order to establish optimal <em>in vitro </em>propagation method for <em>T. palaestinus</em>. Factors of <em>in vitro</em> shooting, rooting, and acclimatization of the <em>in vitro</em> <em>Tetragonolobus palaestinus</em> seedlings were studied using different growth regulators. For <em>in vitro</em> shooting, different cytokinins including benzylamino purine (BAP), kinetin, TDZ, and zeatin were used in increasing concentrations (0.0, 0.3, 0.6, 0.9, 1.2, 1.5, and 2.0 mg l^-1). Using benzylamino purine (BAP produced a maximum of 2.0 shoots/explants on Murashige and Skoog (MS) medium supplemented with 0.3 mg l^-1. Moreover, the effect of different concentrations of IBA (indole-3-butyric acid), IAA (indole-3-acetic acid), andnaphthalene acetic acid (NAA) was evaluated for <em>in vitro</em> rooting. The highest number of roots (4.06 roots/explant) was obtained on MS medium supplemented with 0.3 mg l^-1IBA. All of the plants (100 %) were grown normally after the acclimatization process. Based on these results simple protocol of <em>T. palaestinus</em> <em>in vitro</em> culture was optimized for the first time which can be utilized to do more studies on cell culture and production of active secondary metabolites.</p>