Study On Mutagenic Effects Of Space Environment On Wheat Seed

The mutation of wheat were induced by space environment and ⁶⁰Coγ-ray, differences of cytology effect and protect enzyme activities were compared with the control. At the same time, the effects of chlorophyll fluorescence, Photosynthesis characteristics, Agronomic characteristics were studied on pot-culture experiment in several important growth periods of wheat M₁ generation of mutation. The results will help to explore effects of vegetation growth in Space Environment, provide mutagenic mechanisms of space environment for spaceflisht mutation breeding in crops.The main results are as follows :1. The Wheat seeds were boarded on return satellite, M₁ index of mitosis of tip cells rise, the result showed that space treatment could stimulated mitosis of tip cells on the"Xinong1043"and"Shaan253"two wheat varieties. The main effects of cytology could be observed in M 1were many types of chromosomal aberration and nuclear aberration in root tip cells. For in stance ,we could saw:sticky chromosome,fragments chromosome,bridge chromosome,multi- bridge chromosome and Micronucleus. Chromosoma aberration rate and rate of micronucleus of space treatment were high than control markedly, which showed that wheat chromosome has a certain degree of injury on the space environment. M₁ of space treatment have same effect with lower dosage ⁶⁰Coγ-ray treatment, and more differently with higher dosage ⁶⁰Coγ-ray treatment. All these showed that irradiation taked an important role in mitosis of tip cells.2. The SOD, POD and CAT activities in wheat seedling leaves of M₁ trentent by spaceflisht mutation increased obviously, content of MDA and souble protein were not significant differences than that of control. It's suggested that gene expression of wheat changed thought space environment, thus protecting enzyme systems were stimulated, high protection activities was advantageous to repair mutagenic damage, so maintained balance on metabolism of reactive oxygen species in cell membrane and protected the normal growth of plants.3. The effects of the space shuttle carrying on the chlorophyll fluorescence parameters and photosynthesis characteristics of wheats cultlvars Xinong No.1043 M₁ and Shaan No.253 M₁ were studied.The results showes that the decrement of contents of PSâ…¡primary photochemical efficiency(Fv/Fm),potential activity (Fv/F0),photochemical quenching...