Effects Of Alfalfa Seed Moisture Content On Mutagenic Of Satellite Carrying

Under the impact of the complexity of outer space factors, including microgravity, vacuum, ionizing radiation and zero-magnetic field, the significant changes occurs after flight in orbit at all biological endpoints. Seeds with different moisture content (9%, 11%, 13%, 15%, 17%) of alfalfa variety Zhongmu No.1 were boarded on Shijian-8 satellite.Study on the seed germination, field observation and agronomic traits, chlorophyll content and characteristics of plant photosynthesis, the differences of cell microstructure and ultrastructural were analysised to probe into the effect of space flight factors and seed's moisture content mutagenic effects and interaction mechanism.1 Moisture content of seeds have certain impact on seeds vigor and plant growth. The seeds germination rate, the number of branches, leaf area and plant height significantly increased by the space mutagenesis treatments under the moisture content of 13% and 15%, 17% compared to 9%(nature moisture content); High moisture content of Alfalfa seeds can increase the variation efficiency. After carrying, the seeds germination rate, the number of branches, leaf area and plant height of 13%, 15% and 17% carrying group higher than the untreated control respectively.2 There are some change in photosynthesis and chlorophyll content of different moisture content of alfalfa; 9%,11% group's net photosynthes and chlorophyll content performance negative variation; 13%, 15 %, 17% group are positive variation; But the degrees of variation different. High moisture content variate margin larger groups; satellite carrying the net photosynthetic efficiency of plant photosynthesis and the effects of radiation effective than other obvious indicators of photosynthesis.3 There are some diversities in cell microstructure of carrying groups, but are not significantly. Various groups of moisture content after space flight its cell ultrastructure change, the impact of chloroplasts is greater, the phenomenon of mitochondria empty and crack overflow is also obvious. 15% and 17% carrying group's starch grains of chloroplast is significant, more and biger.4 Moisture content of 13%~17% of Alfalfa seeds incline to high yields variation, variate margin is larger. So moisture content of 13%~17% of alfalfa seeds is appropriate for satellite carrying.