Regulating effect of salicylic acid on the metabolism of active oxygen species and its relation to ethylene biosynthesis in wheat leaves

The regulating effects of salicylic acid(SA)on the metabolism of active oxygen species(AOS) and the relationship between SA inhibiting ethylene biosynthesis and AOS metabolism in wheat leaves were studied.Wheat seedlings were treated by SA solution of different concentrations as follows:in one group the above ground parts of seedling were soaked separately in sets of SA solution for 45min ,in another group the root parts were soaked in SA solution.The second leaves of the two groups were measured after 8h under sunlight. The results showed that H 2O 2 contents,superoxide dismutase (SOD) and phenol specific peroxidase (PPOD)activities increased first and then decreased.Catalase(CAT) activities decreased apparently. Measurement of ethylene production rate showed that there was a significant decrease after slight increase.The results indicated that SA might be involved in the regulation of AOS metabolism,rate of ethylene production was sensitive to exogenous SA treatments,and increasing of O 2 - production rate in leaves could not raise the rate of ethylene production.