Study On Mutagenic Effects Of Space Flight And Gamma Rays On Turfgrass

In order to inquire the mutagenic effects of space flight and gamma rays radiation on turfgrass, the dry seeds of perennial ryegrass(Lolium perenne L.) variety Derby Supreme were flied in space carried by SZ-4 spaceship and radiated by 60~Co gamma rays with different doses in this paper. The treated and CK's seeds were germinated indoors and planted in fields, respectively, to learn their differences in seeds germination and seedlings growth, then POD and EST isozymes of plants were analyzed through PAGE, and the DNA mutation effects of plants were checked by AFLP fingerprintings. That was, the mutation effects of space flight and gamma rays radiation on seeds of perennial ryegrass were probed through four aspects, including seeds germination, seedlings growth, isozymes and DNA level.The results of seeds germination showed that space flight could improve seeds germination power and seeds vigor, but seeds germination rate declined. With regard to the radiation, low dose of gamma rays had no obvious effects on the seeds germination. With the increase of radiation dose, the seeds germination was depressed.The plants height and tillers number were measured and investigated after planting 30 days in fields. The results showed that the height of plants that seeds flied in space were taller than CK plants in general, and the variation of plants height was broader and there were more tillers in plants. The distribution interval of tillers number of 50Gy gamma rays plants was similar to CK plants, but there were more tillers than CK. Also, with the increase of radiation dose, the plants height and tillers number descended.The isozymes analysis showed that there were some differences among different treated materials in zymogram patterns of POD isozymes. Comparing to CK plants, there were 2 POD bands more in plants that seeds flied in space and a special band in plants of 150Gy gamma rays radiation. The results of EST analysis showed that EST patterns of plants that seeds flied in space and radiated by 150Gy gamma rays were similar to CK, but there were some differences in the vigor of isozymes. The EST bands were added or absent in other treated materials compared to CK.The analysis of AFLP fingerprinting showed that there were more differences among different treated materials in DNA level. The highest average mutation percentage was 27.8% in the plants that seeds radiated with 150Gy Gamma rays, the next was the plants that seeds flied in space, which the average mutation percentage was 24.97%, and the lowest one was 18.19% in the plants that seeds radiated with l00Gy Gamma rays. The genetic distance of all materials ranged between 0.109 and 0.226. Regard to the radiation,the seeds germination and seedling growth were depressed with the increase of Gamma rays dose, however, this trend were not approved by the DNA mutation percentage. According to the AFLP fingerprinting, 7 materials could be clustered to 4 groups, that was, CK, materials that seeds radiated by Gamma rays with 50Gy, lOOGy and 300Gy doses were in the same group, other materials including seeds radiated by Gamma rays with 200Gy, 150Gy doses and flied in space were in different groups, respectively.Based on the analysis of seeds germination, seedlings growth, isozymes and DNA mutation, mutagenic effects of space flight and Gamma rays radiation on dry seeds of perennial ryegrass Derby Supreme were proved, which provided the theoretic proofs for the applications of space flight and gamma rays radiation on perennial ryegrass breeding.