Effects Of Priming Agents On Seed Vigor And Physiological And Biochemical Characteristics Of Naturally Aging Sugar Beet

The ageing of plant seeds over a long period of time can lead to a reduction in seed germination,seedling growth and resistance,and even plant death.Seed priming can repair the damage caused by aging to a certain extent,improve the germination rate of seeds and improve the stress resistance of seedlings,which is beneficial to agricultural production and preservation of germplasm resources.In this experiment,Sugar beet Seeds"FASI No.1"and the second generation of expanded seeds stored under natural conditions for 12years were used as experimental materials.Seven priming agents such as PEG-6000 and chitosan were used to initiate the seeds,and the seed vigor and the physiological and bio-chemical indexes of Young Seedling Cotyledon stage were measured after initiation.While exploring the aging mechanism of Sugar beet Seeds,the appropriate initiation treatment methods were screened,It will lay a theoretical foundation for the conservation and reju-venation of Sugar beet Germplasm Resources in the future and provide some application references.The test results are as follows:1.Aging can have a detrimental effect on seeds and can even affect their second gen-eration seed viability.After 12 years of storage under natural conditions,the germination rate of CK₁was 11.11%,far below the germination rate required for actual production,while its physiological and biochemical indicators decreased significantly,and the germi-nation rate of the second generation seeds（CK₂）harvested for its expansion was 41.11%,and the seedlings were not resistant to stress,and the germination rate did not reach the required for field sowing standard（more than 85%germination rate）.2.Seven priming agents,H₂O,H₂O₂,PEG-6000,chitosan,Ca Cl₂,GA₃ and As A,were used to initiate natural aging seeds（CK₁）.The results showed that all different initiation treatments could improve seed vigor and germination rate,but the initiation effects were different.among them,the 12 h pure water soaking,1.0%chitosan,250 mg·L^-1 GA₃,0.6%H₂O₂,25%PEG-6000,1.5%Ca Cl₂ and 80 mg·L^-1 As A were the best treatments for each initiator,and the renovation effect of the aging seeds was the most obvious among all rea-gents.3.Seedling cotyledon stage,some physiological and biochemical indicators related to germination and resistance and seed vigour were significantly correlated.1.0%chitosan triggered the best results,and the germination rate and seed vigor were significantly im-proved,which could increase the germination rate from 11.11%to 67.78%,seed vigor in-creased from 61.38 to 599.85;soluble protein and soluble sugar content increased by 91.06%and 94.81%,respectively,andα-amylase activity increased by 240%compared to CK₁;CAT,POD and SOD activities increased by 72.93%,216.10%and 105.05%,respectively.COX and MDH activities increased by 128.37%and 97.18%,respectively;seedling con-ductivity,MDA content and O₂·^-content decreased by 46.12%,75.10%and 42.29%,re-spectively,compared with CK₁.4.Of all the initiating treatments,250 mg·L^-1 GA₃ was the most effective in increas-ing cellular osmoregulatory substances,α-amylase activity and mitochondrial key enzyme activity.It increased soluble protein content from 7.61 mg·L^-1 to 16.43 mg·L^-1,soluble sugar content from 5.40 mg·L^-1 to 10.61 mg·L^-1,α-amylase activity from 4.30 U·g^-1 to26.70 U·g^-1.COX activity from 4.37 U·g^-1 to 11.06 U·g^-1,MDH activity increased from0.71 U·g^-1 to 1.57 U·g^-1.