Salvadora persica is an endangered medicinal plant due to difficulties in its traditional propagation. It is rich in bioactive compounds that possess many pharmaceutical, antimicrobial activities and widely used in folk medicine. The current study aims at in vitro propagation of Salvadora persica and the application of different nanoparticles (NPs) to induce the synthesis of bioactive and secondary metabolites within the plant. The cellular and genetic responses to the application of different NPs were evaluated. The impact of nanoparticles NPs (ZnO, SiO2, and Fe3O4) on callus growth of Salvadora persica and the production of its active constituent benzyl isothiocyanate was examined, regarding some oxidative stress markers, antioxidant enzymes, and genetic variabilities. An encouraging impact of 0.5 mg/l ZnO NPs on benzyl isothiocyanate production was shown reaching up to 0.905 mg/g callus fresh weight in comparison to 0.539 mg/g in control callus. This was associated with decreasing hydrogen peroxide content and increasing superoxide dismutase and peroxidase activities. The deposition of the NPs on cellular organelles was detected using a transmission microscope. Fifteen Inter-Simple Sequence Repeats (ISSR) primers detected an overall, 79.1% polymorphism among different treatments. A reduction in genomic DNA template stability (GTS) was made and was more pronounced in higher doses of different NPs. This study is a stepping stone in developing a productive protocol for in vitro production of benzyl isothiocyanate from Salvadora persica using NPs as a valuable anticancer compound.

Anthropogenic activity, climate change, pollution, and exploitation of natural resources are some reasons that cause threatening of plant diversity. Silene schimperiana is an endangered plant species in Egypt and is endemic to the high mountain of Saint Katherine Protected Area in southern Sinai. The purpose of the study was the ex situ conservation of Silene schimperiana through in vitro propagation and DNA barcode analysis. To develop an efficient ex situ conservation program of the plant, in vitro propagation protocol has been achieved from shoot tip and stem nodal segment explants of in vitro germinated seedlings. Explants were established in vitro on Murashige and Skoog (MS) medium supplemented with 2.89 μM gibberellic acid (GA3), 1.08 μM α-naphthaleneacetic acid (NAA), and 1.16 μM kinetin (Kin). The highest number of axillary shoots (9.27) was obtained when they were transferred to MS medium supplemented with 4.48 μM 6-benzyl adenine (BA). Hundred percent of multiple axillary shoots were rooted on quarter-strength MS medium supplemented with 4.92 μM indole-3-butyric acid (IBA) and 10.75 μM NAA. Rooted plants were transferred to pots containing a soil-peat mixture (1: 2 v/v) and successfully acclimatized in the greenhouse. Plant identification is a crucial aspect to understand and conserve plant diversity from extinction. DNA barcode analysis of Silene schimperiana was carried out using two chloroplast DNA markers (cpDNA): 1,5-bisphosphate carboxylase/oxygenase large subunit (rbcL) and RNA polymerase subunit (rpoC1) and a nuclear ribosome DNA marker (ncDNA), internal transcribed spacer (ITS). Phylogenetic analysis revealed a successful identification of Silene schimperiana on the species and genus levels and supported the inclusion of Silene schimperiana in genus Silene. In this study, a relevant in vitro propagation method was established to facilitate the recovery of Silene schimperiana, in addition to DNA barcoding of the plant as a tool for effective management and conservation of plant genetic resources.

Background: Asparagus (Asparagus officinalis) is a perennial vegetable of economic importance for its high nutritional and medicinal value. Male plants are more desirable because of their higher spear yield. Therefore, the aim of this study was to evaluate the efficiency of the gibberellin inhibitors; paclobutrazol (PBZ) and cycocel (CCC) for in vitro preservation by encapsulation of in vitro-derived shoot tips of the superior germplasm of the first generation of asparagus male hybrid; cultivar Mary Washington 500W. Methods: An efficient technique for synthetic seeds production was achieved, consisting of 3% (w/v) Na-alginate dissolved in water, Murashige and Skoog (MS) medium, MS medium with the growth inhibitors; PBZ and CCC at different concentrations, and 0.1 M calcium chloride (CaCl₂.2H₂O). Synthetic seeds were stored at 4 ℃ and then cultured after different storage durations (0, 2, 4, 8, 12, 16, 20 and 24 weeks) on MS medium supplemented with 1 mg l⁻¹ kinetin, 0.2 mg l⁻¹ naphthalene acetic acid and 0.5 mg l⁻¹ gibberellic acid for shoot tip multiplication; then, recovered shoots were transferred to MS medium supplemented with 1 mg l⁻¹ indole butyric acid and 0.5 mg l⁻¹ PBZ for rooting. Results: The beads containing 1 mg l⁻¹ PBZ considered the optimum for producing complete well-developed plantlets of Asparagus officinalis from recovered shoot tips after 24 weeks of storage that successfully acclimatized in the greenhouse. Conclusions: This protocol is efficient for in vitro preservation by encapsulation of shoot tips and regeneration of Asparagus officinalis F1 male hybrid (Mary Washington 500w), using anti-gibberellin plant growth regulators within the beads to prolong the duration of storage and provide a continuous supply of the plant.

Stevia rebaudiana Bert. is a non-caloric sweetener plant of medicinal and commercial values. This study was performed to micropropagate Stevia and improve its ability to withstand the sudden shocks of the environmental changes during acclimatization by using endomycorrhizae and/or Pseudomonas fluorescens. In vitro establishment of Stevia was superior by culturing shoot tips and nodal segments of mature plants on Murashige and Skoog medium supplemented with 0.5 mg/l 6-benzyl adenine and 1 mg/l β-naphthalene acetic acid, and nodal segments gave better response when compared to shoot tips. While 6-benzyl adenine alone at 1 mg/l was found to be the most promising concentration for shoots multiplication for four successive subculturing. The best rooting response was obtained on half strength Murashige and Skoog medium supplemented with 1 mg/l β-naphthalene acetic acid. Adding 8 ml/l mycorrhizal root extract gave 100% rooting with the highest mean number and length of roots and shoot height. Inoculation of plantlets with endomycorrhizal spores alone in non-sterilized soil increased the survival percentage to 90% and gave the highest mean number and length of both shoots and roots, as well as leaves number. Moreover, they recorded the highest values of total chlorophyll, NPK and relative water contents. Key words: Stevia, micropropagation, mycorrhizae, mycorrhization helper bacteria.

Silymarin and phenolic compounds have great pharmaceutical applications, particularly as hepatoprotective agents. Silymarin content in Silybum marianum wild populations is low with significant differences between the individuals and the areas of these populations decreased due to the increasing interest in the plant. Therefore, cell suspension culture technique is an alternative and sustainable procedure for the bioproduction and conservation of the plant. The aim of the present study was the production of silymarin and certain phenolic compounds from Silybum marianum cell suspension cultures by the supplementation of the precursor amino acid; L-phenylalanine. Seeds were collected from wild plants at Alexandria desert road and germinated in vitro. Seedlings root segments were cultured on Murashige and Skoog medium supplemented with 4.55 μM 2,4-dichlorophenoxy acetic acid and 4.44 μM 6-benzyladenine for the induction and proliferation of callus. Cell suspension cultures were established in the same medium supplemented with L-phenylalanine at different concentrations (302.68, 605.36 and 908.05 μM). L-Phenylalanine elevated the cells biomass and the accumulation of silymarin and some phenolic compounds. The significantly highest silymarin accumulation reached 66.33% increase compared to the control. This study highlights the potential of L-phenylalanine for the in vitro production of silymarin-rich extracts and protecting the environment by preventing the overcollection of the plant.