Abstract: An improved method based on CTAB was used to extract the total DNA from dry leaves of endangered plant Populus euphratica and P.pruinosa, and to research their reaction system of RAPD-PCR. The results showed that the total DNA extracted by the improved CTAB method could be fit for the RAPD analysis of P.euphratica and P.pruinosa. A suitable RAPD-PCR system for P.euphratica and P.pruinosa was developed as follows: 20 μL PCR solution, including 2.5 mmol·L^-1 Mg²⁺, 0.15 mmol·L^-1 dNTP, 0.2 μmol·L^-1 primer, 100 ng DNA template and 1.5 U Taq DNA polymerase. By testing the stability of the system with 6 polymorphic primer pairs, the results indicated that the developed system could amplify stably and keep a rich polymorphism. These results provided a reference for the further research on both P.euphratica and P.pruinosa at molecular level.

Key words: Populus euphratica, P.pruinosa, DNA extraction, RAPD optimization