Salinity is one of the abiotic stresses that lead to an imbalance in the physiological processes of the plants and also affects potato growth and productivity in maınly semi-arid and growing areas. The accumulation of Na+ and Cl- ions in the cells is very toxic can influence all mechanisms and the enzymatic actions of the plants. In vitro screening of plant genotypes for osmotic stress represents a valuable tool as an alternative to field trials and can be applied based on osmotic stress tolerance. The main goal of this study was to reveal variability in salinity stress tolerance of potato varieties using in vitro screening. Stem cuttings consisting of a single node of different varieties were cultured on Murashige and Skoog (MS) medium supplemented with different concentrations of sodium chloride (NaCl) (0, 50, 100 and 150 mM). The differences among the plantlet length, number of branches, number of nodes, number of the leaflet, leaflet width, leaflet length, root length, number of the root, fresh plantlet weight, dry plantlet weight of all varieties were negatively influenced by all NaCl concentrations tested. Microtuberization and stolon growth of the varieties were also completely inhibited at high concentrations (100-150 mM). The Principal components analysis (PCA) was applied to the data matrix (15 morphological characteristics x 12 potato varieties) of the potato varieties. Also, a hierarchical cluster analysis (HCA) was used to identify the possible nearest and similarity of all morphological characteristics analyzed of the potato varieties. In grouping potato varieties, HCA and PCA results were found to be similar. We can speculate about the responses of morphological similarities of the potato varieties against salt stress. We concluded that Innovator and Kennebec are respectively the most salt-tolerant varieties. Hermes was moderately salt-tolerant and microtuberization capacity of Slaney was also high under salt stress conditions.

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IntroductionAgrobacterium tumefaciens is the most efficient way of introducing foreign genes into plants. Plants such as tobacco, potato, eggplant and other species of the family Solanaceae can easily be transformed by A. tumefaciens. However, cereals, legumes, and trees are recalcitrant to A. tumefaciens-mediated genetic transformation. Therefore, several strategies have been developed to increase genetic transformation frequency in recalcitrant plant species. These include the use of different bacterial density, inoculation and cocultivation methods, and explants (Kumar et al., 2002;Park, 2006;Sharma et al., 2009). In addition, the application of phenolic compounds to inoculation and cocultivation media also enhances transformation, even in recalcitrant plant species (Dutt and Grosser, 2009;Rashid et al., 2010).Squirting cucumber (Ecballium elaterium (L.) A.Rich.) is a poisonous plant that is used for medicinal purposes (Sezik, 1997). It contains different compounds, such as α-elaterin (cucurbitacin E), β-elaterin (cucurbitacin B), elatericine A (cucurbitacin D), and elatericine B (cucurbitacin I) in different plant organs. It also contains sterols, phenolic compounds, vitamins, flavonoids, alkaloids, resin, starch, amino acids, and fatty acids (Koç, 2002;Memişoğlu and Toker, 2002). Compounds found in leaves, stems, roots, and testa are poisonous and show antibacterial activities (Oskay and Sarı, 2007;Koca et al., 2010;Adwan et al., 2011). Similarly, Adwan et al. (2011) also reported antibacterial activity of ethanol extracts obtained from mature dried fruit of squirting cucumber, which exerted negative effects on the growth of Staphylococcus aureus and Candida albicans. However, in our unpublished preliminary studies, we found that the juice of mature fruits induced growth of E. coli and Staphylococcus aureus. Therefore, the present study was designed, for the first time, to check the effects of fresh juice of mature fruits of squirting cucumber on growth of A. tumefaciens and its gene transfer efficiency to tobacco and potato plants.

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Callus induction and proliferation of Alkanna orientalis var. orientalis and Alkanna sieheana containing valuable alkannin/shikonin (A/S) derivates were investigated using leaf base and stem segment explants. Stem segments and cotyledonary leaf base of both species were cultured on Murashige and Skoog medium fortified with different concentrations of BAP, Kn, NAA, IAA and IBA for callus induction and shoot regeneration. High frequency reproducible, prolific and compact calli formation was obtained from the stem segments of both species in all media tested. The frequency variations of callus induction and shoot regeneration were discussed in terms of different species, plant growth regulators and explant resources. A. orientalis and A. sieheana may be considered to be alternative plants for the A/S production in vitro.