Research On The Resistance Of Maize Irradiated With Different Doses Of Heavy Ions

Drought is an important factor that affects the growth and yield of maize.This paper studies the physiological,morphological and gene expression levels of M5 generation of Yong 19 maize inbred lines with different doses of 7Li heavy ion irradiation.The main results are as follows:(I)The photosynthetic rate of Maize under drought stress was decreased with the increasing dealing time.Compared with Maize of 0Gy,Maize of M5 generation of 30 Gy and 50 Gy irradiated by 7Li had a higher photosynthetic rate after drought stress.Maize of 30 Gy had different degrees of changes that benefit the growth of corn in leaf number,stem diameter,plant height and leaf area.Study on photosynthetic rate and morphological observation show that Maize of 30 Gy had a higher drought resistance,then Maize of 50 Gy.(II)The mRNA expression levels of ZmMnSOD,ZmPLC,ZmPPDK and ZmAtg8 were studied before and after drought stress.The results show that the expression of the resistance related genes in different doses of maize presents complex expression changes with the increase of stress time.After drought stress,the expression levels of photosynthesis related gene,ZmPPDK,antioxidant related gene,ZmMnSOD,and signal transduction related gene,ZmPLC,in M5 generation of Maize of Yong 19 maize inbred lines irradiated by 7Li with 30 Gy and 50 Gy were in some degree of higher.Among them,the results of ZmPPDK were consistent with the results of photosynthetic rate.Study on the physiological and morphological observation and the expression of the resistance-related genes show that Maize of 30 Gy and 50 Gy had the higher ability of photosynthesis and strong drought resistance after drought stress.The results of mutagenic effects of Zinnia elegans Jacq.by irradiation show as follows: compared with control,the germination rate of Zinnia irradiated by fast neutron of 1Gy increased.The radiation can cause variation of phenotypic traits of zinnia such as leaf type,phyllotaxy and color of the flower.1Gy can be used as a reference irradiation dose of fast neutron.Fast neutron radiation and space radiation could individually induce M1 generation of Zinnia apparent properties and DNA variation.However,it also needs further cultivation and research of mutant strains to make sure if the variation of phenotypic traits is stable.