Effects of sunflower artificial aging on seed vigor and physiological characteristics.

[Objective] The aim was to study the effects of sunflower artificial aging on seed vigor and physiological characteristics.[Method]The varieties of seed germination capacity,vigor of germination,germination index,vigor index,peroxidase (POD) activity,superoxide dismutase (SOD) activity and malondialdehyde (MDA) content for four sunflower germplasms Such as 'SunM 20','Deep Purple Minle','Da San Kui Hua 4' and 'Ji Kui 24' were studied under high temperature and high humidity conditions(100% RH,45 ℃) for different days(0,2,4,6,8,10 d).[Result]The result showed that the germination capacity,vigor of germination,germination index,vigor index,POD activity,SOD activity declined gradually with the increase of seed aging days,whereas MDA content enhanced by degrees; The differences of resistance to artifical aging existed among the four accessions,'SunM 20' was the most resistant one,and exhibited the strongest seed vigor,highest activities of two protective enzyme(POD,SOD) and lowest content of MDA at the uniform condition,moreover,the seed vigor and protective enzyme activities of 'SunM 20' changed slowest among the four materials during the aging process. [Conclusion]The distinct reduction of POD,SOD activities maybe the main reasons for the decrease of sunflower seed vigor at the artificial aging,and the gradual accumulation of a few MDA accelerated seeds aging.