Preliminary Studies Of Space Ionizing Radiation Induced Mutations In Plants

With the application and development of space science and technology,space mutation breeding of plants,as an important branch,is playing an increasingly prominent role.Space environment,featured by high vacuum,microgravity,geomagnetic field and charged particle radiation,is proved to be an irreplaceable condition for the research and development of space biological breeding.A large number of application researches have been done effectively,but rare in theoretical,experimental and application research about genetic variation of plants through ionizing radiation.In this research,the author attempts to explore the plant variation induced by space environment in the aspects of geomagnetic field and charged particle radiation in space,which are precisely the urgent problems in the field.For these purposes,this research was designed,taking flower plants of mealycup sage(salvia farinacea benth.)and cyclamen as the object,closely combining space ionizing radiation test and ground molecular biological experiment with field planting,as well as theoretical and experiment research with application research.Some innovative ideas were obtained:Theoretical research: with Shieldose2 model,radiation dose in orbit of "Shenzhou 8",quantitative "discontinuous" and "cyclical" radiation spectrum of spacecraft in anomaly zone of the South Atlantics and average energy flux of the main charged particles in the orbit,radiation shield dose and features of particle energy distribution in reverse back were obtained.Experiment research: molecular biological experiment showed that DNA molecules of all plants carried in space changed,and according to the planting experiment,flower shape,color,flower yield,height and apparent characters of the space plants changed significantly,showing that the results obtained from the RAPD dendrogram agreed well with phenotypic traits of the experimental plants.These findings suggest that DNA molecular variation and changes in apparent characters were directly resulted in by ionizing radiation in space.Application research: through screening out the useful variant strains for apparent characters of the two kinds of plants,the variant strains including "triple buds" of cyclamen that are beneficial for genetic stability were obtained for the first time,which is of promotional value for further cultivation of new varieties of the plant.