Dry seeds of Hordeum vulgare cv. Zafer-160 were surface sterilized by rapid immersion, first treated with 95% eth-anol and then 20% sodium hypochlorite for 15 min and rinsed three times with sterile water. Ten seeds were ger-minated at dark, on plates between filter papers embedded in 0.1, 0.5 and 1.0 lM HBR-supplemented distilled water for 48 h with their control. Total two plates of HBR for each concentration with three separate experiments were used. All cultures were kept at dark in a controlled growth chamber (25?C). The number of germinated roots (primary and seminal roots) (Hochholdinger et al. 2007) was recorded after 48 h. About 1 mg of HBR (H1267, Sigma) was dissolved in ethanol to yield a 10 mM stock solution.
Cytological analyses
HBR treated and untreated control group roots were fixed in 1:3 aceto-alcohol. After fixation, roots were hydrolized in 1 mol/l HCl for 3 min and stained in 2% aceto-orcein for 1 h. Densely stained regions of the root tips were separated for preparation. In squash preparations mitosis were investigated and mitotic index and abnormalities were
calculated. About 1,200 cells were counted for each serial of treatments and control materials.