Cell synchronization and isolation of chromosomes from Chinese fir root tips for flow cytometric analysis.

OBJECTIVES: To optimize treatment parameters to synchronize the cell cycle of Chinese fir root tip meristem cells. RESULTS: Optimal mitotic indices were achieved by treating seedlings with 1.25 mM hydroxyurea for 10 h, incubating for 7 h without chemical treatment to release the hydroxyurea block, and then treating emerging roots with 0.05 % colchicine for 16 h. The mitotic index of synchronized Chinese fir root tips was over 30 %. Suspensions of intact chromosomes were prepared using a simple slicing procedure. CONCLUSIONS: The chromosome preparations were suitable for flow cytometric characterization and sorting. The chromosome peaks of the observed flow karyotype resembled the predicted flow karyotype calculated from the Chinese fir chromosome size.