Research On Physiological And Biochemical Characteristics And Differential Expression Gene During Artificial Aging In Elymus Sibiricus L.

Elymus sibiricus L.is a high-quality forage widely distributed in the northwest region of China.But in the process of seed preservation,the seed of this species may be aged because of the lack of regeneration and poor preservation of the environment.The seeds of Elymus sibiricus L.cv.Nongmu were treated in the artificial aging conditions at high –temperature(40?)and high-humidity(100%RH)of aging method to obtain different relative Germination rate(75.21%,54.00%,36.00%)by taking the seeds with 100% relative Germination rate with no aging treatment as a contro in the study,the corresponding aging time was 0 h,24 h,72 h and 144 h.Seed vigor,physiological and biochemical characteristics,and differential expression gene were discussed after artificial aging.The possible reason for its aging is revealed,which provides a theoretical basis for its seed production and long-term preservation,and lays the foundation for the aging mechanism and physiological and molecular mechanisms of the resistance of the Elymus Sibiricus germplasm.The main results were showed as follows:(1)The germination potential,relative germination rate,relative germination index,relative vigor index,antioxidant enzyme activity and the content of soluble protein were decreased gradually along with the aging time in Elymus sibiricus Lcv.Nongmu.Conductivity and the content of malondialdehyde,Proline,soluble sugar gradually increased.Aging treatment inhibits the germination of Elymus sibiricus Lcv.Nongmu.The structure and function of cell membranes were destroyed gradually along with the aging time.(2)The correlation analysis showed that the activity of Superoxide dismutase,Peroxidase,Catalase and soluble protein showed extremely significant positive correlation with activity index,and the electrical conductivity,malondialdehyde,proline and soluble sugar had significant or extremely significant negative correlation with activity index.The results showed that the above metabolic regulators and related enzyme activities could be used as an index for judging the degree of aging of the seeds of of Elymus sibiricus L.cv.Nongmu.(3)256 pairs of primer combinations were used to analyze the four aging gradients of cDNA-AFLP,and 136 pairs of polymorphic primers with clear bands were screened out 2720 items were obtained,and 50 up-regulated pairs expressed in the aging process were recovered.(4)The recovered 50 differential fragments were re-amplified subjected to 22 brighter bands were sent for sequencing.The blast sequences of 19 sequences were sequenced by NCBI.The 19 differentially expressed fragments were homologous to the known sequences.Their functions mainly involve cell growth,energy metabolism,defense and repair mechanisms.6 other differentially expressed fragments have not found homologous sequences in the database for the time being,and they may be the unknown gene sequence associated with aging.