Samih Tamimi

Silver nanoparticles (AgNPs) have numerous applications in plant biotechnology. The unique biological activities of AgNPs in reducing microbial contamination and promoting in vitro plant growth have encouraged their use in the development of novel culture systems for the in vitro cultivation of several plant species. In this study, the influence of (80 nm–100 nm) AgNPs on the micropropagation of banana was examined by incorporating AgNPs into shoot multiplication and rooting media at concentrations of 3 mg/L–15 mg/L. Biometric parameters for shoot multiplication (number of shoots/explant, shoot length and leaf surface area) and root development (number of roots/explant and root length) were analysed. In addition, shoot chlorophyll content, proline content and the possible impact of lipid peroxidation on membrane stability of plantlets were estimated. The results showed that all concentrations of AgNPs stimulated shoot growth and enhanced root development. The highest response was ob...

A high-performance protocol for callus induction was devised using germinating mature embryos of two local wheat (Triticum aestivum L.) landraces as explant. The results showed that callus development from germinating embryos was rapid starting one day after culture with an induction rate 20 to 25% higher than those of soaked embryos. In addition, the mean rate of growth of callus developed from germinating embryos was 60 to 70% higher than those cultured from soaked embryos. This study also demonstrated a higher frequency of green spots formation(48 to 56%)on callus derived from germinating embryos compared to their soaked counterpart (24 to 28%), suggesting a better differentiation potential of callus cultures derived from germinating embryo. These findings indicate that germinating mature embryo is more suitable explant for wheat callus induction and regeneration than the soaked mature embryo commonly employed for wheat callus culture.

ABSTRACT The nutritional characteristics of the seeds of 3 pea cultivars (Pisum sativum L.) namely; normal-leafed, semi-leafed (JI 1195) and leafless (JI 1198) have been compared regarding proximate analysis, vitamins and mineral content as well as organoleptic quality. Protein, ash, fat, crude fiber, nitrogen free extract (NFE), calcium, zinc, niacin and energy content were similar for the three cultivars. The content of iron, sodium potassium and phosphorous were significantly higher for the normal-leafed type than those of the other two types. However, the contents of vitamins B1, B2 and carotenes were significantly higher for the semi-leafed and the leafless cultivars. The organoleptic testing showed variations among the three cultivars regarding general appearance, flavour and overall acceptance. The leafless cultivar had the highest score for seed softness. The semi-leafed cultivar, however, had the highest score regarding the general appearance, flavour and overall acceptance. The results indicate that the new cultivars were as good as the normal leafed type in many aspects and were superior to it in some others. Thus, and because of their reported low irrigation needs, they are recommended for growth in arid and semi-arid areas like Jordan.

Uridine strongly stimulated adventitious root formation in stem cuttings of sunflower (Helianthus annuus L.), mung bean (Vigna radiata L.) and common bean (Phaseolus vulgaris L.). A dose response curve of uridine induced rooting showed that the optimum concentration of uridine was 0.1 µM. At all concentrations employed, uridine had no significant effect on root elongation. The rooting response of stem cuttings to the optimal concentration of indole-3-butyric acid (10 µM) in combination with 0.1 µM uridine did not significantly differ from their response to either of these compounds when applied alone. However, the rooting response of the cuttings to sub-optimal IBA (0.01 µM) was significantly stimulated by uridine. These findings suggested that uridine may have stimulated rooting by increasing the sensitivity of the rooting tissue to auxin.

The genetic diversity and the N2 fixation potential of 10 rhizobial isolates nodulating Phaseolus vulgaris in the soils of the Jordan valley was investigated. Random amplified polymorphic DNA (RAPD) analysis showed that isolates consisted of two major genetic groups and revealed a low level of diversity among the isolates. Significant differences existed in the symbiotic potential of the isolates examined.