Nuclei were released from 1 cm2 of leaf tissue. For FCM analysis, rose (Rosa hybrid a
cv. Akito 2n=4x=28) (khosravi et al., 2008) and untreated Ocimum basilicum nuclei were
used as an internal standard, by chopping with a sharp razor blade simultaneously in the
petri dish in 400 μl of extraction buffer (CyStain-UV precise Partec). For removing the
phenolic impurities, PVP-40 was added to the buffer. Then the suspension was filtered into
small tubes through a 30 μm Celltris disposable nylon filter and were kept on ice for 10
min. For the coloration of these samples, 1.6 ml of DAPI staining solution (4´, 6-diamino-2-
phenylindole) added and samples were put into the flow cytometer and the DNA
histograms were created. The DNA content of each sample was evaluated in 10000 nuclei.
Ten leaf samples of diploid control plants and putative tetraploids were analyzed
alternately.