Studies On Physiological And Biochemical Changes And Genomic DNA Damages By ISSR Of Two Kinds Of Caragana Seeds During Artificial Aging

A study on deterioration of seeds of Caragana.korshinskii.Kom and Caragana.Micro -phlla.Lam was conducted to analyze the physiological and biochemical changes, and the ISSR fingerprints of genomic DNA damages of seeds were established during artificial aging under 50% methanol solution and 40℃, 100%RH treatment. Understan -ding the changes involved in this process would enable to selection of better vigor test for the evaluation seed quality of C.korshinskii.Kom and C.microphlla.Lam, The research on the mechanism of seed deterioration will help to provide instruction for the preservation and storage germplasm of seeds. The results showed:The seed germination percentage and germination index of two Caragana species decreased significantly with seed aging time. Under the much similar aging conditions, the germination percentage is the similar to the result of short-lived grass aging seed, which indicated that seeds vigor of two Caragana species easily to be deteriorated with time. At the same germination rate level, the soaking liquid conductivity of seeds treated by high temperature and high humidity aging was significantly higher than that of seed with methanol treatment. The reason probably is due to more serious damage of plasma membrane under the high temperature and high humidity aging treatment.The decrease contents of soluble protein and activity of acid phosphoesterase were noticed during artificial aging, which indcated that metabolic system was destroied in ageing seeds. This is probably the another reason of responsible for seed vigor degradation C.korshinskii.Kom and C.microphlla.Lam.The seed vigor of C.microphlla.Lam is generally higher than that of C.korshinskii. -Kom in this experiment, such as the germination percentage, the content of souble protein, the ACP activity and the POD activity.Results of the principal component analysis of the seven indexes showed that the ACP and SOD activity are the main factors related to the seeds vigor change, and the reliable indexes for the examination of seed vigor.The suitable primers were screened suitable for the study of genomic DNA damages of C.korshinskii.Kom and C.microphlla.Lam during artificial aging, and the fingerprints of ISSR were established for the two Caragana species seeds with artificial aging. A comparative study was made on changes of ISSR bands of artificial aging seeds with six primers U835, U857, U808, U811, U834 and U868. The results showed the damages of genomic DNA of the two Caragana species seeds is randomic. The binding sites of the randomic primer in genomic DNA were start to be destroyed and the ISSR amplified bands of artificial aging seeds were dilute and even disappeared completely with the increased degree of artificial aging.The results indicated that DNA quality is very important to the ISSR research of aging seeds, and the SDS is a simple and affective method of DNA extraction for the study of aging seeds.