Sunflower (Heliantus annuus L.) foliar extract inhibited the germination of mustard (Sinapis alba L.) seeds. It was accompanied by increased membrane deterioration and enhanced H2O2 production. ABA concentration increased in seeds imbibed in the presence of sunflower phytotoxins, whereas ethylene production was inhibited. Activity of key enzymes of ethylene biosynthetic pathway: ACC synthase and ACC oxidase in seeds treated by sunflower extract was decreased. Sunflower phytotoxins seems to disturb the hormonal balance between ABA and ethylene, which is regarded as the factor controlling the germination of seeds and growth of young seedlings.
ABA, ACC oxydase, ACC synthase, ethylene, germination, mustard seeds, sunflower phytotoxins
