RAPD Researches On Genomic DNA Damages Of Cucumber Seeds During Artificial Aging And Its Osmoprimed Repairment With Peg

With the rapid development of molecular biology, RAPD (Random Amplified Polymorphic DNA) has been widely applied in biological fields. In this paper, RAPD was applied to DNA polymorphism analysis of artificially aged and PEG osmoprimed artificially aged seeds of cucumber, and the fingerprints of RAPD were established genomic DNA damages of cucumber seeds during artificial aging and its osmoprimed repairment with PEG.The paper discussed the most appropriate factors that influenced RAPD. The results showed that the suitable template DNA quantity was 40-80ng in each reaction; the best Mg2+concentration for RAPD was 2.5-3.5 mmol. L-1; the suitable quantity of Taq polymerase was 1.0-2.0U; the best dNTPs concentration was 100-200 mol. L-1 and the best concentration of random primer was 1.0-1.8 mol. L-1.Primer screening. The results showed that 92 primers were screened from 103 primers that could result in stable and clear DNA bands. In addition, the effects of PEG of different molecular weights, different treatment concentration, and different treatment times on the vigor of cucumber seeds were evaluated. The results showed that the best choice was the treatment of 25% PEG6000 for 24 hours.The primers, which were suitable for the study of genomic DNA damages of cucumber during artificial aging and its osmoprimed repairment with PEG, were screened and thefingerprints of RAPD were established among the cucumber seeds with artificial aging and PEG treatment. 22 from 92 primers were suitable for cucumber seeds of artificial aging and 16 from 92 primers were suitable for cucumber seeds treated by PEG.A comparative study was made on DNA bands of cucumber seeds of artificial aging and PEG osmoprimed repairment with seven primers S190, S200, S300, S359, S475, S1 140 and S2144. The results showed that DNA bands of artificial aging seeds were dilute and even disappeared completely, but new DNA bands were amplified and were like as compared with control from PEG osmoprimed artificial aged seeds. Therefore, the fingerprint of RAPD was established with regard to genomic DNA damages of cucumber seeds during artificial aging and its osmoprimed repairment with PEG.The conductivity and seed germination of cucumber seeds of artificial aging and PEG treatment were tested. It could be concluded that seed vigor was closely related to genomic DNA damage and repairment.As a result, the paper shows that RAPD can be applied to DNA polymorphism analysis of artificially aged and PEG osmoprimed artificially aged seeds of cucumber and RAPD has good reliability and accuracy if the reaction system and the reaction procedure are established.