Optimised techniques for mitotic studies in sweet cherry (P. avium L.)

ABSTRACT: Sweet cherry (Prunus avium L.) is one of the Prunoideae subfamily of Rosaceae, which is characterized by small chromosomes and the preparation its cells for studying of mitotic chromosomes is difficult. Different methods at each stage of slide preparation, from collecting root tips to chromosome staining, were applied to determine the best method, for studying its chromosomes and karyotype preparation. Results showed root tips which were collected from germinating seeds were better than those from young seedlings. Optimized technique consisted of placing samples in 0.002 molar 8-hydroxy quinoline for 4 hours at 4 °C. After washing by distilled water, they were fixed in pinar solution (6 ethanol: 3 chloroform: 2 propionic acid) for 48-72 hours at 4 °C and stored in fresh pinar at -18 °C. Chromosomes then were hydrolyzed by 1N HCl at 60 °C and stained with feulgen and squashed in 2% aceto-carmine. This improved protocol allowed the identification of chromosomes in mitosis division.