Response On Physiological And Biochemical Characteristics And Genomic During Artificial Aging Of Three Varieties Elymus Dahuricus Seeds

A study on three varieties Elymus L. seeds was conducted to discuss the changesof physiological and biochemical characteristics and the damage of DNA as testingmaterial under artificial accelerated aging with high temperature (45℃) and highhumidity(RH100%).we expected to find the physiological index that influence seedsvigor and explore the specific strips of ISSR in aging seeds′DNA.The results willhelp us to realize the reason of seeds aging,to provide the scientific basis forexploring the method that determine Elymus L.seeds vigor,to search theoretical basisfor Tibetan Plateau′germplasm storage and production. Test conclusion wereshowed:1.Under the aging time continuing,The germination rate,germinationenergy,vigor index and germination index of three varieties Elymus L. seeds weredeclined and the rate of declining of germination energy was faster than others.Afteraging treatment, the vigor index of Elymus sibiricus seed is faster than Elymusnutans and Elymus atratus under rate of declining.This showed that the strongestresistance to aging is Elymus sibiricus, Elymus nutans is weaker, Elymus atratus isthe weakest.2.The correlation between seed vigor and electrical conductivity were negativecorrelation,there is no obvious rising in Elymus atratus and Elymus atratus, Elymussibiricus′electrical conductivity did not change.3.The early aging treatment, protective enzyme activity (POD,SODactivity)were markedly decreased, which leads to increased reactive oxygen and free radicals,with the extension of aging time, the declining trend gently and slowly, which isprobably active adapt for aging. Elymus sibiricus decline is faster than Elymusnutans and Elymus atratus, this indicate Elymus nutans and Elymus atratus seedswere stronger than Elymus sibiricus in aging resistance 4.The content of MDA was increased with aging time in seeds, The early agingwas rising early and the later period was slowly. The increasing of content of MDAaggravated accumulation of toxic substances, which inhibit the POD、 SODactivity.So the lipid peroxidation is an important reason for the aging of the seeds.5.With the aging time increasing, the content of soluble sugar increased, contentof soluble protein decreased,which may be due to the internal metabolic systemdamage and enzyme activity degradation.6.The results correlation analyze that the between vigor index and electricalconductivity were no significant and negative correlation in the three varieties, thecontent of MDA and soluble sugar were significant and negative correlation;The seedvigor index and SOD, POD activity and soluble protein content were significant andpositive correlation.7.The results of principal component anylysis showed vigor index,SOD,PODactivity, soluble sugarand MDA were reliable index for three varieties Elymus L.seeds′quality, electrical conductivity was not.8.Three varieties Elymus L. seeds ISSR primers were screened in ordor toestablishing ISSR-PCR optimization system. The seed DNA was amplified by tenprimers,the resulta showed with the aging time increasing, DNA′damage occursrandomly,and the range of the damage was in200-500bp and1000bp-1500bp that ismolecular weight, which showed to reduce the strips and some specific bandsincreased.The bands that was serious damage disappeared.