Effects of salt stress on micropropagation of potato (Solanum tuberosum L.)

Six cultivars of potato (Solanum tuberosum L.) Bartina, Spunta, Cardinal, Desirée, Timate and Fabula were assayed in vitro for salinity (NaCl) tolerance. A modified single-node cuttiang bioassay was used in which cultivars were exposed to a range of NaCl levels (0, 40, 80 and 120 Mm), in a Murashige and Skoog medium, for 1 month. Evaluations were performed twice for each cultivar at each salt level. Six vegetative growth parameters (shoot and root length, fresh and dry weights) were measured at the time of harvest and corrected for differences in cultivar vigor. Fresh weight of shoot and length of shoot decreased by given range levels of NaCl. The effect of all treatments was very drastic on length and weight of root. The cultivar Bartina exhibited greater tolerance to the highest salt doses. Plants of this cultivar had greater shoot length than other cultivars at all salt concentrations tested. The results indicated that cultivar "Bartina" is more salt tolerant than other cultivars studied.Key words: Potato, Solanum tuberosum L, salinity, in vitro, micropropagation

Regeneration of Algerian

Stigma/style somatic embryogenesis is one of the efficient methods in plant regeneration of most Citrus ssp., without inducing somaclonal variations. Furthermore, somatic embryogenesis from style/stigma proved to be effective in the elimination of the main citrus virus and virus-like diseases. This technique was applied on Algerian citrus collection. Different Citrus species [Citrus sinensis (L.) Osbeck, C. limon (L.) Burm, C. reticulata Blanco, C. paradisi Macfad, C. reshni Hort. ex Tan., C. jambhiri Lush and C. maxima (Burm.) Merrill] were chosen and tested for the presence of the main virus and virus-like agents. Most of the genotypes showed to be infected, mainly by viroid agents. Closed flowers were collected and in vitro cultured on a Murashige and Skoog (MS) medium supplemented with 6- benzylaminopurine. All explants produced callus about 4 to 9 days after culture initiation, whereas embryogenesis occurred after 38 to 150 days in most of the cultured genotypes. Formed embryos were cultured in a single tube before in vivo acclimatization. After sanitary assays, regenerated plants were shown to be free from the agents detected in the mother trees.Key words: Algeria, citrus germplasm, plant regeneration, sanitation, somatic embryogenesis

Essential oil of Thymus munbyanus subsp. coloratus from Algeria: chemotypification and in vitro biological activities

Thymus munbyanus subsp. coloratus (Lamiaceae) is a small shrub endemic to Algeria and Morocco where is found in lawns, rockeries and mountainous regions. From a phytochemical point of view this taxon has never been characterized. In this work we have analysed the chemical compositions of the essential oils obtained from inflorescences and vegetative parts by GC-MS. A new chemotype, i.e. borneol-chemotype, was characterized for the first time in the species. Furthermore, we assessed the biological activities of essential oils, namely the antioxidant, antimicrobial and cytotoxicity on tumor cells that were evaluated by the DPPH, ABTS and FRAP, disc diffusion, and MTT methods, respectively. Biological assays highlighted a moderate inhibitory effect on S. aureus, E. coli and C. albicans (IZD in the range 9-10 mm), and noteworthy cytotoxicity on A375 human melanoma cells (IC50 of 46.95 g/ml)

Rosmarinus eriocalyx: An alternative to Rosmarinus officinalis as a source of antioxidant compounds

Rosmarinus eriocalyx is an aromatic evergreen bush endemic to Algeria where it is used as a condiment to flavour soups and meat and as a traditional remedy. In the present work we have analyzed for the first time the phenolic composition of polar extracts obtained from stems, leaves and flowers of R. eriocalyx by HPLC, and determined the antioxidant and antimicrobial effects by DPPH, ABTS, FRAP, ORAC and agar disc diffusion methods, respectively. Results showed that ethanolic extracts of leaves and flowers are a rich source of phenolic compounds, mainly rosmarinic acid, carnosic acid and carnosol that are the main responsible for the noteworthy antioxidant activity observed in the assays. This study showed that R. eri- ocalyx might be a spice to be included in the European food additive list and used as a preservative agent besides R. officinalis