Screening Of Artificial Aging Conditions And Effects Of Ultrasound And Ascorbic Acid Treatment On The Vigor Of The Aged Haloxylon Ammodendron Seeds

Seeds may undergo irreversible aging during long-term storage,causing a decline in seed quality and seed yield.It is an important problem for agriculture,forestry and animal husbandry production and germplasm resource conservation to Improving storage conditions to delay seed aging or to repair the damage of aging seeds with appropriate restoration measures.The seed vigor and seedling quality can be improved by using reasonable repairing methods,such as physical,chemical and biological methods.At present,there are many studies on the effect of one or several restoration measures on the vigor of aged seeds,but few studies on the combined effect of two restoration methods on aged seeds.In order to discover the rule of Haloxylon ammodendron seed aging and to explore a reasonable seed repair technology,the following two groups of experiments were conducted on Haloxylon ammodendron seeds:（1）Selection of suitable aging temperature and time for Haloxylon ammodendron seeds:Artificial accelerated aging was adopted to simulate natural aging,The seeds were aged for 24、36、48、60、72、84 and 96 h at 39、41、43 and 45℃,respectively.The average germination rate of seeds at different temperature and time were analyzed,and the suitable aging temperature and time of Haloxylon ammodendron seeds were screened out.（2）Orthogonal matrix test method is used to study the influence of ultrasound temperature,ultrasound time,ascorbic acid（AsA）concentration and AsA soaking time on the seeding germination and physiological characteristics of artificially aged Haloxylon ammodendron seeds,and to study whether there was a repair effect on the seeds and select the optimal treatment condition.The conclusions of this study are as follows:（1）germination percentage at different aging temperature and aging time can reflect the difference of Haloxylon ammodendron seed vigor level,Aging temperature and aging time have significant effects（P<0.05）on Haloxylon ammodendron seed germination rate.Seed germination rate decreased gradually with the increase of aging temperature and time,Low aging temperature or short aging time had little effect on seed production,and high aging temperature or long aging time can causing a too much seed damage.In this study,the aging temperature of 41℃and aging time of 36 h can be used as the suitable aging conditions for Haloxylon ammodendron seeds.（2）Treatment of aged Haloxylon ammodendron seeds with appropriate doses of ultrasound and AsA can Significantly increased（P<0.05）the seed germination rate,germination potential,germination index and seedling length,decreased the soaking liquid conductivity,the malondialdehyde（MDA）content and the proline content,increased the soluble protein content,and increased the superoxide dismutase（SOD）,peroxidase（POD）and the catalase（CAT）activity.It is obtained by orthogonal range analysis that ultrasonic temperature is one of the most important factors that influence seed germination and seed vigor.Principal component analysis shows that the optimal treatment condition of aged Haloxylon ammodendron seeds were an ultrasound temperature of 25℃,an ultrasound time of 20 min,an AsA concentration of 300 mg·L^-1and an AsA soaking time 24 h.